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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.1214 | Todd M. Tripp | Todd M. Tripp (1), Kenneth R. Sembach (2), David V. Bowen (3), Blair
D. Savage (4), Edward B. Jenkins (3), Nicolas Lehner (5), and Philipp Richter
(6); ((1) Univ. Massachusetts, (2) STScI, (3) Princeton Univ., (4) Univ.
Wisconsin, (5) Univ. Notre Dame, (6) Univ. Potsdam) | A High-Resolution Survey of Low-Redshift QSO Absorption Lines:
Statistics and Physical Conditions of O VI Absorbers | Accepted for publication in the Astrophysical Journal Supplements.
Substantially revised and improved based on comments from the referee and
other readers | 2008ApJS..177...39 | 10.1086/587486 | null | astro-ph | null | Using high-resolution UV spectra of 16 low-z QSOs, we study the physical
conditions and statistics of O VI absorption in the IGM at z < 0.5. We identify
51 intervening (z_{abs} << z_{QSO}) O VI systems comprised of 77 individual
components, and we find 14 "proximate" systems (z_{abs} ~ z_{QSO}) containing
34 components. For intervening systems [components] with rest-frame equivalent
width W_{r} > 30 mA, the number of O VI absorbers per unit redshift dN/dz =
15.6(+2.9/-2.4) [21.0(+3.2/-2.8)], and this decreases to dN/dz = 0.9(+1.0/-0.5)
[0.3(+0.7/-0.3)] for W_{r} > 300 mA. The number per redshift increases steeply
as z_{abs} approaches z_{QSO}, and some proximate absorbers have substantially
lower H I/O VI ratios. The lower proximate ratios could be partially due to
ionization effects but also require higher metallicities. We find that 37% of
the intervening O VI absorbers have velocity centroids that are well-aligned
with corresponding H I absorption. If the O VI and the H I trace the same gas,
the relatively small differences in line widths imply the absorbers are cool
with T < 10^{5} K. Most of these well-aligned absorbers have the
characteristics of metal-enriched photoionized gas. However, the O VI in the
apparently simple and cold systems could be associated with a hot phase with T
~ 10^{5.5} K if the metallicity is high enough to cause the associated broad Ly
alpha absorption to be too weak to detect. We show that 53% of the intervening
O VI systems are complex multiphase absorbers that can accommodate both lower
metallicity collisionally-ionized gas with T > 10^{5} K and cold photoionzed
gas.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 16:45:09 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Feb 2008 13:56:40 GMT"
}
] | 2009-07-14T00:00:00 | [
[
"Tripp",
"Todd M.",
""
],
[
"Sembach",
"Kenneth R.",
""
],
[
"Bowen",
"David V.",
""
],
[
"Savage",
"Blair D.",
""
],
[
"Jenkins",
"Edward B.",
""
],
[
"Lehner",
"Nicolas",
""
],
[
"Richter",
"Philipp",
""
],
[
";",
"",
""
]
] |
0706.1215 | Lars Kadison | Lars Kadison | Depth three towers and Jacobson-Bourbaki correspondence | 20 pp. (10 pp. supersede math.RA/0703328) | null | null | null | math.RA math.AC | null | We introduce a notion of depth three tower of three rings C < B < A as a
useful generalization of depth two ring extension. If A = End B_C and B | C is
a Frobenius extension, this also captures the notion of depth three for a
Frobenius extension in math.RA/0107064 and math.RA/0108067 such that if B | C
is depth three, then A | C is depth two (cf. math.QA/0001020). If A, B and C
correspond to a tower of subgroups G > H > K via the group algebra over a fixed
base ring, the depth three condition is the condition that subgroup K has
normal closure K^G contained in H. For a depth three tower of rings, there is a
pre-Galois theory for the ring End {}_BA_C and coring (A \otimes_B A)^C
involving Morita context bimodules and left coideal subrings. This is applied
in the last two sections to a specialization of a Jacobson-Bourbaki
correspondence theorem for augmented rings to depth two extensions with depth
three intermediate division rings.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:34:06 GMT"
}
] | 2007-06-11T00:00:00 | [
[
"Kadison",
"Lars",
""
]
] |
0706.1216 | Evgeny Akhmedov | Evgeny Akhmedov | Do charged leptons oscillate? | LaTeX, 15 pages, no figures. V3: discussion in secs. 4 and 7
expanded, references added. Results and conclusions unchanged | JHEP0709:116,2007 | 10.1088/1126-6708/2007/09/116 | null | hep-ph astro-ph hep-ex | null | The question of whether charged leptons oscillate is discussed in detail,
with a special emphasis on the coherence properties of the charged lepton
states created via weak interactions. This analysis allows one to clarify also
an important issue of the theory of neutrino oscillations.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:35:19 GMT"
},
{
"version": "v2",
"created": "Sun, 10 Jun 2007 09:54:17 GMT"
},
{
"version": "v3",
"created": "Fri, 27 Jul 2007 17:31:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Akhmedov",
"Evgeny",
""
]
] |
0706.1217 | N. J. A. Sloane | Chao Tian, Vinay A. Vaishampayan, N. J. A. Sloane | Constant Weight Codes: A Geometric Approach Based on Dissections | 9 pages, 6 figures | IEEE Trans. Inform. Theory 55 (2009), 1051-1060 | null | null | math.CO | null | We present a novel technique for encoding and decoding constant weight binary
codes that uses a geometric interpretation of the codebook. Our technique is
based on embedding the codebook in a Euclidean space of dimension equal to the
weight of the code. The encoder and decoder mappings are then interpreted as a
bijection between a certain hyper-rectangle and a polytope in this Euclidean
space. An inductive dissection algorithm is developed for constructing such a
bijection. We prove that the algorithm is correct and then analyze its
complexity. The complexity depends on the weight of the code, rather than on
the block length as in other algorithms. This approach is advantageous when the
weight is smaller than the square root of the block length.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:41:24 GMT"
}
] | 2014-09-17T00:00:00 | [
[
"Tian",
"Chao",
""
],
[
"Vaishampayan",
"Vinay A.",
""
],
[
"Sloane",
"N. J. A.",
""
]
] |
0706.1218 | S Brendle | S. Brendle | A general convergence result for the Ricci flow in higher dimensions | Final version, to appear in Duke Math Journal | null | null | null | math.DG math.AP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let (M,g_0) be a compact Riemannian manifold of dimension n \geq 4. We show
that the normalized Ricci flow deforms g_0 to a constant curvature metric
provided that (M,g_0) x R has positive isotropic curvature. This condition is
stronger than 2-positive flag curvature but weaker than 2-positive curvature
operator.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:43:59 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 18:09:49 GMT"
},
{
"version": "v3",
"created": "Sun, 20 Apr 2008 21:14:01 GMT"
},
{
"version": "v4",
"created": "Tue, 30 Sep 2008 14:46:59 GMT"
}
] | 2008-09-30T00:00:00 | [
[
"Brendle",
"S.",
""
]
] |
0706.1219 | Pawel Wocjan | Thomas Decker, Jan Draisma, Pawel Wocjan | Efficient Quantum Algorithm for Identifying Hidden Polynomials | 17 pages | null | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a natural generalization of an abelian Hidden Subgroup Problem
where the subgroups and their cosets correspond to graphs of linear functions
over a finite field F with d elements. The hidden functions of the generalized
problem are not restricted to be linear but can also be m-variate polynomial
functions of total degree n>=2.
The problem of identifying hidden m-variate polynomials of degree less or
equal to n for fixed n and m is hard on a classical computer since
Omega(sqrt{d}) black-box queries are required to guarantee a constant success
probability. In contrast, we present a quantum algorithm that correctly
identifies such hidden polynomials for all but a finite number of values of d
with constant probability and that has a running time that is only
polylogarithmic in d.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:44:20 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Apr 2008 17:41:14 GMT"
},
{
"version": "v3",
"created": "Tue, 2 Sep 2008 15:54:39 GMT"
}
] | 2008-09-02T00:00:00 | [
[
"Decker",
"Thomas",
""
],
[
"Draisma",
"Jan",
""
],
[
"Wocjan",
"Pawel",
""
]
] |
0706.1220 | Mark Voit | M. Sun, M. Donahue, G. M. Voit | H-alpha tail, intracluster HII regions and star-formation: ESO137-001 in
Abell 3627 | 16 pages, 1 table, 6 figures (4 in color), emulateapj5.sty, to appear
in ApJ, December 10, 2007, v671, n1. Spectroscopic data added; minor revision
and conclusions unchanged. Please read the paper with the full-resolution
figures at http://www.pa.msu.edu/~sunm/eso137_001_Ha_v1.3.ps.gz | null | 10.1086/522690 | null | astro-ph | null | We present the discovery of a 40 kpc H-alpha tail and at least 29
emission-line objects downstream of a star-forming galaxy ESO 137-001 in the
rich, nearby cluster A3627. The galaxy is known to possess a dramatic 70 kpc
X-ray tail. The detected H-alpha tail coincides positionally with the X-ray
tail. The H-alpha emission in the galaxy is sharply truncated on the front and
the sides near the nucleus, indicating significant ram pressure stripping. ESO
137-001 is thus the first cluster late-type galaxy known unambiguously with
both an X-ray tail and an H-alpha tail. The emission-line objects are all
distributed downstream of the galaxy, with projected distance up to 39 kpc from
the galaxy. From the analysis on the H-alpha_{off} frame and the estimate of
the background emission-line objects, we conclude that it is very likely all 29
emission-line objects are HII regions in A3627. The high surface number density
and luminosities of these HII regions (up to 10^40 ergs/s) dwarf the previously
known examples of isolated HII regions in clusters. We suggest that star
formation may proceed in the stripped ISM, in both the galactic halo and
intracluster space. The total mass of formed stars in the stripped ISM of ESO
137-001 may approach several times 10^7 solar masses. Therefore, stripping of
the ISM not only contributes to the ICM, but also adds to the intracluster
stellar light through subsequent star formation. The data also imply that ESO
137-001 is in an active stage of transformation, accompanied by the build-up of
a central bulge and depletion of the ISM.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:50:48 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 02:02:07 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Sun",
"M.",
""
],
[
"Donahue",
"M.",
""
],
[
"Voit",
"G. M.",
""
]
] |
0706.1221 | Tabetha Boyajian | T. S. Boyajian, D. R. Gies, E. K. Baines, P. Barai, E. D. Grundstrom,
M. V. McSwain, J. R. Parks, R. L. Riddle, W. T. Ryle, and D. W. Wingert | Radial Velocities of Six OB Stars | Accepted for publication in PASP July 2007 issue | null | 10.1086/520707 | null | astro-ph | null | We present new results from a radial velocity study of six bright OB stars
with little or no prior measurements. One of these, HD 45314, may be a
long-period binary, but the velocity variations of this Be star may be related
to changes in its circumstellar disk. Significant velocity variations were also
found for HD 60848 (possibly related to nonradial pulsations) and HD 61827
(related to wind variations). The other three targets, HD 46150, HD 54879, and
HD 206183, are constant velocity objects, but we note that HD 54879 has
H$\alpha$ emission that may originate from a binary companion. We illustrate
the average red spectrum of each target.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:56:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boyajian",
"T. S.",
""
],
[
"Gies",
"D. R.",
""
],
[
"Baines",
"E. K.",
""
],
[
"Barai",
"P.",
""
],
[
"Grundstrom",
"E. D.",
""
],
[
"McSwain",
"M. V.",
""
],
[
"Parks",
"J. R.",
""
],
[
"Riddle",
"R. L.",
""
],
[
"Ryle",
"W. T.",
""
],
[
"Wingert",
"D. W.",
""
]
] |
0706.1222 | Angela Bonaccorso | A. Garc\'ia-Camacho (Pisa), G. Blanchon (Pisa), A. Bonaccorso (Pisa),
D.M. Brink (Oxford) | All orders proton breakup from exotic nuclei | 5 latex pages, 3 figures, 2 tables. Accepted for publication in Phys.
Rev. C | Phys.Rev.C76:014607,2007 | 10.1103/PhysRevC.76.014607 | null | nucl-th nucl-ex | null | We present a semiclassical method to treat the proton breakup from a weakly
bound state in an exotic nucleus. The Coulomb interactions between the proton,
core and target are treated to all orders and including the full multipole
expansion of the Coulomb potential. The nuclear proton-target interaction is
also treated to all orders. The core-target interaction is included as an
absorption. The method is semi-analytical thus allowing for a detailed
understanding of the short range and long range effects of the interactions in
the reaction dynamics. It explains also the origin of possible asymmetries in
the core parallel momentum distributions when the full multipole expansion of
the Coulomb potential is used. Calculations are compared to results of other,
fully numerical, methods and to experimental data in order to establish the
accuracy and reliability of the method.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 17:59:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"García-Camacho",
"A.",
"",
"Pisa"
],
[
"Blanchon",
"G.",
"",
"Pisa"
],
[
"Bonaccorso",
"A.",
"",
"Pisa"
],
[
"Brink",
"D. M.",
"",
"Oxford"
]
] |
0706.1223 | Jos\'e Cleriston Campos de Souza Mr | Jose C. C. de Souza, Valerio Faraoni | The phase space view of f(R) gravity | 14 pages, 2 figures, published in Classical and Quantum Gravity;
references added | Class.Quant.Grav.24:3637-3648,2007 | 10.1088/0264-9381/24/14/006 | null | gr-qc astro-ph hep-th | null | We study the geometry of the phase space of spatially flat
Friedmann-Lemaitre-Robertson-Walker models in f(R) gravity, for a general form
of the function f(R). The equilibrium points (de Sitter spaces) and their
stability are discussed, and a comparison is made with the phase space of the
equivalent scalar-tensor theory. New effective Lagrangians and Hamiltonians are
also presented.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:09:57 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jul 2007 18:04:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"de Souza",
"Jose C. C.",
""
],
[
"Faraoni",
"Valerio",
""
]
] |
0706.1224 | Vincent Rivasseau | V. Rivasseau | Constructive Matrix Theory | 12 pages, 3 figures | JHEP 0709:008,2007 | 10.1088/1126-6708/2007/09/008 | null | hep-th | null | We extend the technique of constructive expansions to compute the connected
functions of matrix models in a uniform way as the size of the matrix
increases. This provides the main missing ingredient for a non-perturbative
construction of the $\phi^{\star 4}_4$ field theory on the Moyal four
dimensional space.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:12:15 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Rivasseau",
"V.",
""
]
] |
0706.1225 | Grazyna Stasinska | Grazyna Stasinska, Guillermo Tenorio-Tagle, Monica Rodriguez, William
J. Henney | Enrichment of the ISM by metal-rich droplets and the abundance bias in
HII regions | 14 pages, 5 figures, accepted in Astronomy and Astrophysics | null | 10.1051/0004-6361:20065675 | null | astro-ph | null | We critically examine a scenario for the enrichment of the interstellar
medium (ISM) in which supernova ejecta follow a long (10^8 yr) journey before
falling back onto the galactic disk in the form of metal-rich ``droplets'',
These droplets do not become fully mixed with the interstellar medium until
they become photoionized in HII regions. We investigate the hypothesis that the
photoionization of these highly metallic droplets can explain the observed
``abundance discrepancy factors'' (ADFs), which are found when comparing
abundances derived from recombination lines and from collisionally excited
lines, both in Galactic and extragalactic HII regions. We derive bounds of
10^{13}--10^{15} cm on the droplet sizes inside HII regions in order that (1)
they should not have already been detected by direct imaging of nearby nebulae,
and (2) they should not be too swiftly destroyed by diffusion in the ionized
gas. From photoionization modelling we find that, if this inhomogeneous
enrichment scenario holds, then the recombination lines strongly overestimate
the metallicities of the fully mixed HII regions. The abundances derived from
collisionally excited lines also suffer some bias, although to a much lesser
extent. In the absence of any recipe for correcting these biases, we recommend
the discarding of all objects showing large ADFs from studies of galactic
chemical evolution. These biases must also be kept in mind when comparing the
galactic abundance gradients for elements derived from recombination lines with
those derived from collisionally excited lines. Finally, we propose a set of
observations that could be undertaken to test our scenario and improve our
understanding of element mixing in the ISM.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:20:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stasinska",
"Grazyna",
""
],
[
"Tenorio-Tagle",
"Guillermo",
""
],
[
"Rodriguez",
"Monica",
""
],
[
"Henney",
"William J.",
""
]
] |
0706.1226 | Young-Heon Kim | Young-Heon Kim and Robert J. McCann | On the cost-subdifferentials of cost-convex functions | 16 pages | null | null | null | math.AP | null | We are interested in the cost-convex potentials in optimal mass transport
theory, and we show by direct and geometric arguments the equivalence between
cost-subdifferentials and ordinary subdifferentials of cost-convex functions,
under the assumptions A0, A1, A2, and A3W on cost functions introduced by Ma,
Trudinger, and Wang. The connectivity of contact sets of optimal transport maps
follows as a direct corollary. Our approach is quite different from the
previous result of Loeper which he obtained as the first step toward his
Hoelder regularity theory of potential functions, and which was based upon
approximation using the regularity theory of Ma, Trudinger, and Wang. The
result in this paper improves his result, by relaxing certain geometrical
assumptions on the domains and targets; it also completes his Hoelder
regularity theory of potential functions on the round sphere, by making it
self-contained.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:45:52 GMT"
}
] | 2007-06-11T00:00:00 | [
[
"Kim",
"Young-Heon",
""
],
[
"McCann",
"Robert J.",
""
]
] |
0706.1227 | C. A. de S. Pires | C. A. de S. Pires | Invisible Z decay width bounds on active-sterile neutrino mixing in the
(3+1) and (3+2) models | 10 pages, 5 figures | Mod.Phys.Lett.A24:475-483,2009 | 10.1142/S0217732309028345 | null | hep-ph | null | In this work we consider the standard model extended with singlet sterile
neutrinos with mass in the eV range and mixed with the active neutrinos. The
active-sterile neutrino mixing renders new contributions to the invisible Z
decay width which, in the case of light sterile neutrinos, depends on the
active-sterile mixing matrix elements only. We then use the current
experimental value of the invisible Z decay width to obtain bounds on these
mixing matrix elements for both (3+1) and (3+2) models.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:47:10 GMT"
}
] | 2009-03-31T00:00:00 | [
[
"Pires",
"C. A. de S.",
""
]
] |
0706.1228 | Rubens Ramos Viana | Wellington Alves de Brito and Rubens Viana Ramos | Quantum information technology with Sagnac interferometer:
Interaction-free measurement, quantum key distribution and quantum secret
sharing | 15 pages and 9 figures | null | 10.1080/09500340701633113 | null | quant-ph | null | The interferometry of single-photon pulses has been used to implement quantum
technology systems, like quantum key distribution, interaction-free measurement
and some other quantum communication protocols. In most of these
implementations, Mach-Zehnder, Michelson and Fabry-Perot interferometers are
the most used. In this work we present optical setups for interaction-free
measurement, quantum key distribution and quantum secret sharing using the
Sagnac interferometer. The proposed setups are described as well the quantum
protocols using them are explained.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:47:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"de Brito",
"Wellington Alves",
""
],
[
"Ramos",
"Rubens Viana",
""
]
] |
0706.1229 | Alexander Dolgov | A.D. Dolgov | Cosmological Charge Asymmetry and Rare Processes in Particle Physics | Presented at Les Rencontres de Physique de La Vallee d'Aoste, March,
4-10, 2007, La Thuile, Aosta Valley, Italy; 5 pages, 1 figure | null | null | null | hep-ph astro-ph | null | Two scenarios of low temperature baryogenesis in theories with TeV scale
gravity are discussed. It is argued that strong gravity at TeV energies is very
favorable for baryogenesis. In both scenarios the proton decay is either absent
or suppressed far below existing bounds. On the other hand, neutron-antineutron
oscillations are at the verge of discovery. Some other rare decays with
non-conservation of lepton or baryon numbers are predicted.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:53:46 GMT"
}
] | 2007-06-11T00:00:00 | [
[
"Dolgov",
"A. D.",
""
]
] |
0706.1230 | A. R. P. Rau | A. R. P. Rau | Three bodies bind even when two do not: Efimov states and Fano
resonances in atoms and nuclei | 2 figures | null | null | null | quant-ph | null | Efimov's prediction more than three decades ago that three-body bound states
can exist when the pairwise attractions do not bind or only support weakly
bound states of a pair, has remained unconfirmed till just the past year. This
lecture provides the pedagogical background for recent work on Efimov states in
neutron-rich nuclei done with I. Mazumdar (TIFR) and V. S. Bhasin (Delhi
University), and published in Phys. Rev. Lett. 97, 062503 (2006). Both these
nuclear systems and recent observations of cold cesium atoms provide the first
clear evidence for the existence of Efimov states.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 18:54:23 GMT"
}
] | 2007-06-11T00:00:00 | [
[
"Rau",
"A. R. P.",
""
]
] |
0706.1231 | Chethan Krishnan | Jarah Evslin, Chethan Krishnan | The Black Di-Ring: An Inverse Scattering Construction | v3: 2 subsections added, typos fixed, more refs, journal version. v4:
a transcription error in the ADM mass fixed | Class.Quant.Grav.26:125018,2009 | 10.1088/0264-9381/26/12/125018 | null | hep-th gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We use the inverse scattering method (ISM) to derive concentric
non-supersymmetric black rings. The approach used here is fully
five-dimensional, and has the modest advantage that it generalizes readily to
the construction of more general axi-symmetric solutions.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 19:48:12 GMT"
},
{
"version": "v2",
"created": "Sat, 30 Jun 2007 17:19:47 GMT"
},
{
"version": "v3",
"created": "Tue, 2 Jun 2009 10:54:56 GMT"
},
{
"version": "v4",
"created": "Tue, 15 Dec 2009 13:04:47 GMT"
}
] | 2009-12-15T00:00:00 | [
[
"Evslin",
"Jarah",
""
],
[
"Krishnan",
"Chethan",
""
]
] |
0706.1232 | Jeffrey Tollaksen Dr. | Yakir Aharonov and Jeff Tollaksen | New Insights on Time-Symmetry in Quantum Mechanics | null | VISIONS OF DISCOVERY: New Light on Physics, Cosmology, and
Consciousness, ed. R. Y. Chiao, M. L. Cohen, A. J. Leggett, W. D. Phillips,
and C. L. Harper, Jr. Cambridge: Cambridge University Press, 2007 | null | null | quant-ph | null | A review of new aspects concerning time-symmetry in Quantum Mechanics.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 19:36:29 GMT"
}
] | 2007-06-11T00:00:00 | [
[
"Aharonov",
"Yakir",
""
],
[
"Tollaksen",
"Jeff",
""
]
] |
0706.1233 | Stefano Ansoldi | Stefano Ansoldi and Eduardo I. Guendelman | Universes out of almost empty space | LaTeX (RevTeX), 4 pages, 1 figure. A few typos corrected and some
references added; structure streamlined (changes reflected in a slightly
modified abstract); small, non-substantial modifications in the figure | Prog.Theor.Phys.120:985-993,2008 | 10.1143/PTP.120.985 | KUNS-2095 | gr-qc hep-th | null | Baby universes (inflationary or non--inflationary) are regions of spacetime
that disconnect from the original ambient spacetime, which we take to be
asymptotically flat spacetime. A particular kind of baby universe solution,
involving string--like matter, is studied to show that it can be formed by
``investing'' an arbitrarily small amount of energy, i.e. it can appear from an
almost flat space at the classical level. Since this possibility has not yet
been clearly recognized in the literature, we then discuss in detail its
properties, relevance and possible generalizations.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 19:53:08 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Jun 2007 12:37:44 GMT"
},
{
"version": "v3",
"created": "Tue, 18 Sep 2007 02:03:15 GMT"
}
] | 2008-12-25T00:00:00 | [
[
"Ansoldi",
"Stefano",
""
],
[
"Guendelman",
"Eduardo I.",
""
]
] |
0706.1234 | Jorge Antezana | Jorge Antezana, Enrique Pujals and Demetrio Stojanoff | Convergence of iterated Aluthge transform sequence for diagonalizable
matrices II: $\lambda$-Aluthge transform | 24 pages | null | null | null | math.FA | null | Let $\lambda \in (0,1)$ and let $T$ be a $r\times r$ complex matrix with
polar decomposition $T=U|T|$. Then, the $\la$- Aluthge transform is defined by
$$ \Delta_\lambda (T )= |T|^{\lambda} U |T |^{1-\lambda}. $$ Let
$\Delta_\lambda^{n}(T)$ denote the n-times iterated Aluthge transform of $T$,
$n\in\mathbb{N}$. We prove that the sequence
$\{\Delta_\lambda^{n}(T)\}_{n\in\mathbb{N}}$ converges for every $r\times r$
{\bf diagonalizable} matrix $T$. We show regularity results for the two
parameter map $(\la, T) \mapsto \alulit{\infty}{T}$, and we study for which
matrices the map $(0,1)\ni \lambda \mapsto \Delta_\lambda^{\infty}(T)$ is
constant.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 19:53:37 GMT"
}
] | 2007-06-11T00:00:00 | [
[
"Antezana",
"Jorge",
""
],
[
"Pujals",
"Enrique",
""
],
[
"Stojanoff",
"Demetrio",
""
]
] |
0706.1235 | E. W. Thommes | Edward W. Thommes, Geoffrey Bryden, Yanqin Wu and Frederic A. Rasio | From mean-motion resonances to scattered planets: Producing the Solar
System, eccentric exoplanets and Late Heavy Bombardments | 12 pages, 7 figures, submitted to ApJ | null | 10.1086/525244 | null | astro-ph | null | We show that interaction with a gas disk may produce young planetary systems
with closely-spaced orbits, stabilized by mean-motion resonances between
neighbors. On longer timescales, after the gas is gone, interaction with a
remnant planetesimal disk tends to pull these configurations apart, eventually
inducing dynamical instability. We show that this can lead to a variety of
outcomes; some cases resemble the Solar System, while others end up with
high-eccentricity orbits reminiscent of the observed exoplanets. A similar
mechanism has been previously suggested as the cause of the lunar Late Heavy
Bombardment. Thus, it may be that a large-scale dynamical instability, with
more or less cataclysmic results, is an evolutionary step common to many
planetary systems, including our own.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 19:56:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Thommes",
"Edward W.",
""
],
[
"Bryden",
"Geoffrey",
""
],
[
"Wu",
"Yanqin",
""
],
[
"Rasio",
"Frederic A.",
""
]
] |
0706.1236 | Bruce Cohen I | B.I. Cohen, E. A. Williams and H. X. Vu | Kinetic-Ion Simulations Addressing Whether Ion Trapping Inflates
Stimulated Brillouin Backscattering Reflectivities | 56 pages, 20 figures | null | 10.1063/1.2784449 | UCRL-JRNL-231518 | physics.plasm-ph | null | An investigation of the possible inflation of stimulated Brillouin
backscattering (SBS) due to ion kinetic effects is presented using
electromagnetic particle simulations and integrations of three-wave
coupled-mode equations with linear and nonlinear models of the nonlinear ion
physics. Electrostatic simulations of linear ion Landau damping in an ion
acoustic wave, nonlinear reduction of damping due to ion trapping, and
nonlinear frequency shifts due to ion trapping establish a baseline for
modeling the electromagnetic SBS simulations. Systematic scans of the laser
intensity have been undertaken with both one-dimensional particle simulations
and coupled-mode-equations integrations, and two values of the electron-to-ion
temperature ratio (to vary the linear ion Landau damping) are considered. Three
of the four intensity scans have evidence of SBS inflation as determined by
observing more reflectivity in the particle simulations than in the
corresponding three-wave mode-coupling integrations with a linear ion-wave
model, and the particle simulations show evidence of ion trapping.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 19:43:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cohen",
"B. I.",
""
],
[
"Williams",
"E. A.",
""
],
[
"Vu",
"H. X.",
""
]
] |
0706.1237 | Bruno Barboza Uchoa | B. Uchoa, C.-Y. Lin, and A. H. Castro Neto | Tailoring Graphene with Metals on Top | 5 pages, 4 figures | Phys. Rev. B 77, 035420 (2008) | 10.1103/PhysRevB.77.035420 | null | cond-mat.mtrl-sci cond-mat.str-el | null | We study the effects of metallic doping on the electronic properties of
graphene using density functional theory in the local density approximation in
the presence of a local charging energy (LDA+U). The electronic properties are
sensitive to whether graphene is doped with alkali or transition metals. We
estimate the the charge transfer from a single layer of Potassium on top of
graphene in terms of the local charging energy of the graphene sheet. The
coating of graphene with a non-magnetic layer of Palladium, on the other hand,
can lead to a magnetic instability in coated graphene due to the hybridization
between the transition-metal and the carbon orbitals.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:00:00 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jun 2007 20:15:39 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Jan 2008 22:02:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Uchoa",
"B.",
""
],
[
"Lin",
"C. -Y.",
""
],
[
"Neto",
"A. H. Castro",
""
]
] |
0706.1238 | Alfonso V. Ramallo | Francesco Benini, Felipe Canoura, Stefano Cremonesi, Carlos Nunez,
Alfonso V. Ramallo | Backreacting Flavors in the Klebanov-Strassler Background | 33 pages, 2 figures;v2: typos corrected | JHEP 0709:109,2007 | 10.1088/1126-6708/2007/09/109 | null | hep-th | null | In this paper we present new analytic solutions of pure Type IIB supergravity
plus D7-branes describing the addition of an arbitrary number of flavors to the
Klebanov-Tseytlin and Klebanov-Strassler backgrounds. We provide a precise
field theory dual and a detailed analysis of the duality cascade which
describes its RG flow. Matchings of beta functions and anomalies between the
field theory and the string setup are presented. We give an understanding of
Seiberg duality as a large gauge transformation on the RR and NSNS potentials.
We also analyze the UV behavior of the field theory, that as suggested by the
string background can be associated with a duality wall.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 18:36:03 GMT"
},
{
"version": "v2",
"created": "Sat, 16 Jun 2007 17:21:36 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Benini",
"Francesco",
""
],
[
"Canoura",
"Felipe",
""
],
[
"Cremonesi",
"Stefano",
""
],
[
"Nunez",
"Carlos",
""
],
[
"Ramallo",
"Alfonso V.",
""
]
] |
0706.1239 | Joshua Eisner | J.A. Eisner | Water vapour and hydrogen in the terrestrial-planet-forming region of a
protoplanetary disk | 15 pages, 3 figures. Appeared in Nature May 31. Supplementary
information available at http://www.nature.com/nature | Nature 447:562-564,2007 | 10.1038/nature05867 | null | astro-ph | null | Planetary systems, ours included, are formed in disks of dust and gas around
young stars. Disks are an integral part of the star and planet formation
process, and knowledge of the distribution and temperature of inner disk
material is crucial for understanding terrestrial planet formation, giant
planet migration, and accretion onto the central star. While the inner regions
of protoplanetary disks in nearby star forming regions subtend only a few
nano-radians, near-IR interferometry has recently enabled the spatial
resolution of these terrestrial zones. Most observations have probed only dust,
which typically dominates the near-IR emission. Here I report spectrally
dispersed near-IR interferometric observations that probe gas (which dominates
the mass and dynamics of the inner disk), in addition to dust, within one
astronomical unit of the young star MWC 480. I resolve gas, including water
vapor and atomic hydrogen, interior to the edge of the dust disk; this
contrasts with results of previous spectrally dispersed interferometry
observations. Interactions of this accreting gas with migrating planets may
lead to short-period exoplanets like those detected around main-sequence stars.
The observed water vapor is likely produced by the sublimation of migrating icy
bodies, and provides a potential reservoir of water for terrestrial planets.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:00:09 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Eisner",
"J. A.",
""
]
] |
0706.1240 | Hiranya V. Peiris | Hiranya V. Peiris (U. Chicago), Daniel Baumann (Princeton), Brett
Friedman (UC Irvine), Asantha Cooray (UC Irvine) | Phenomenology of D-Brane Inflation with General Speed of Sound | 23 pages, 11 figures, v2: version accepted by PRD; minor
clarifications and references added to the text. Higher resolution figures
are available in the published version. v3: post-publication correction of
typo in Eq. 87. No results/conclusions changed | Phys.Rev.D76:103517,2007 | 10.1103/PhysRevD.76.103517 | null | astro-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A characteristic of D-brane inflation is that fluctuations in the inflaton
field can propagate at a speed significantly less than the speed of light. This
yields observable effects that are distinct from those of single-field slow
roll inflation, such as a modification of the inflationary consistency relation
and a potentially large level of non-Gaussianities. We present a numerical
algorithm that extends the inflationary flow formalism to models with general
speed of sound. For an ensemble of D-brane inflation models parameterized by
the Hubble parameter and the speed of sound as polynomial functions of the
inflaton field, we give qualitative predictions for the key inflationary
observables. We discuss various consistency relations for D-brane inflation,
and compare the qualitative shapes of the warp factors we derive from the
numerical models with analytical warp factors considered in the literature.
Finally, we derive and apply a generalized microphysical bound on the inflaton
field variation during brane inflation. While a large number of models are
consistent with current cosmological constraints, almost all of these models
violate the compactification constraint on the field range in four-dimensional
Planck units. If the field range bound is to hold, then models with a
detectable level of non-Gaussianity predict a blue scalar spectral index, and a
tensor component that is far below the detection limit of any future
experiment.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 05:17:18 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Nov 2007 22:27:07 GMT"
},
{
"version": "v3",
"created": "Mon, 24 Nov 2008 18:33:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Peiris",
"Hiranya V.",
"",
"U. Chicago"
],
[
"Baumann",
"Daniel",
"",
"Princeton"
],
[
"Friedman",
"Brett",
"",
"UC Irvine"
],
[
"Cooray",
"Asantha",
"",
"UC Irvine"
]
] |
0706.1241 | Eugene Chiang | Eugene I. Chiang and Ruth A. Murray-Clay | Inside-Out Evacuation of Transitional Protoplanetary Disks by the
Magneto-Rotational Instability | Accepted to Nature Physics June 7, 2007. The manuscript for
publication is embargoed per Nature policy. This arxiv.org version contains
more technical details and discussion, and is distributed with permission
from the editors. 10 pages, 4 figures | null | 10.1038/nphys661 | null | astro-ph | null | How do T Tauri disks accrete? The magneto-rotational instability (MRI)
supplies one means, but protoplanetary disk gas is typically too poorly ionized
to be magnetically active. Here we show that the MRI can, in fact, explain
observed accretion rates for the sub-class of T Tauri disks known as
transitional systems. Transitional disks are swept clean of dust inside rim
radii of ~10 AU. Stellar coronal X-rays ionize material in the disk rim,
activating the MRI there. Gas flows from the rim to the star, at a rate limited
by the depth to which X-rays ionize the rim wall. The wider the rim, the larger
the surface area that the rim wall exposes to X-rays, and the greater the
accretion rate. Interior to the rim, the MRI continues to transport gas; the
MRI is sustained even at the disk midplane by super-keV X-rays that Compton
scatter down from the disk surface. Accretion is therefore steady inside the
rim. Blown out by radiation pressure, dust largely fails to accrete with gas.
Contrary to what is usually assumed, ambipolar diffusion, not Ohmic
dissipation, limits how much gas is MRI-active. We infer values for the
transport parameter alpha on the order of 0.01 for GM Aur, TW Hyd, and DM Tau.
Because the MRI can only afflict a finite radial column of gas at the rim, disk
properties inside the rim are insensitive to those outside. Thus our picture
provides one robust setting for planet-disk interaction: a protoplanet interior
to the rim will interact with gas whose density, temperature, and transport
properties are definite and decoupled from uncertain initial conditions. Our
study also supplies half the answer to how disks dissipate: the inner disk
drains from the inside out by the MRI, while the outer disk photoevaporates by
stellar ultraviolet radiation.
| [
{
"version": "v1",
"created": "Sun, 10 Jun 2007 17:14:28 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Chiang",
"Eugene I.",
""
],
[
"Murray-Clay",
"Ruth A.",
""
]
] |
0706.1242 | Chieh-Jen Yang | C.-J. Yang, Ch. Elster, and D. R. Phillips | Subtractive renormalization of the NN scattering amplitude at leading
order in chiral effective theory | 16 pages, 11 figures | Phys.Rev.C77:014002,2008 | 10.1103/PhysRevC.77.014002 | null | nucl-th | null | The leading-order nucleon-nucleon (NN) potential derived from chiral
perturbation theory consists of one-pion exchange plus a short-distance contact
interaction. We show that in the 1S0 and 3S1-3D1 channels renormalization of
the Lippmann-Schwinger equation for this potential can be achieved by
performing one subtraction. This subtraction requires as its only input
knowledge of the NN scattering lengths. This procedure leads to a set of
integral equations for the partial-wave NN t-matrix which give
cutoff-independent results for the corresponding NN phase shifts. This
reformulation of the NN scattering equation offers practical advantages,
because only observable quantities appear in the integral equation. The
scattering equation may then be analytically continued to negative energies,
where information on bound-state energies and wave functions can be extracted.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:47:51 GMT"
},
{
"version": "v2",
"created": "Wed, 23 Jan 2008 21:17:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yang",
"C. -J.",
""
],
[
"Elster",
"Ch.",
""
],
[
"Phillips",
"D. R.",
""
]
] |
0706.1243 | Philip Hopkins | Philip F. Hopkins, Lars Hernquist, Thomas J. Cox, Dusan Keres
(Harvard/CfA) | A Cosmological Framework for the Co-Evolution of Quasars, Supermassive
Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity | 34 pages, 27 figures, submitted to ApJ. Fixed appearance of Figure 1 | Astrophys.J.Suppl. 175 (2008) 356-389 | 10.1086/524362 | null | astro-ph | null | (Abridged) We develop a model for the cosmological role of mergers in the
evolution of starbursts, quasars, and spheroidal galaxies. Combining halo mass
functions (MFs) with empirical halo occupation models, we calculate where major
galaxy-galaxy mergers occur and what kinds of galaxies merge, at all redshifts.
We compare with observed merger MFs, clustering, fractions, and small-scale
environments, and show that this yields robust estimates in good agreement with
observations. Making the simple ansatz that major, gas-rich mergers cause
quasar activity, we demonstrate that this naturally reproduces the observed
rise and fall of the quasar luminosity density from z=0-6, as well as quasar
LFs, fractions, host galaxy colors, and clustering as a function of redshift
and luminosity. The observed excess of quasar clustering on small scales is a
natural prediction of the model, as mergers preferentially occur in regions
with excess small-scale galaxy overdensities. We show that quasar environments
at all observed redshifts correspond closely to the empirically determined
small group scale, where mergers of gas-rich galaxies are most efficient. We
contrast with a secular model in which quasar activity is driven by bars/disk
instabilities, and show that while these modes probably dominate at Seyfert
luminosities, the constraints from clustering (large and small-scale),
pseudobulge populations, disk MFs, luminosity density evolution, and host
galaxy colors argue that they must be a small contributor to the z>1 quasar
luminosity density.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:05:34 GMT"
},
{
"version": "v2",
"created": "Mon, 18 Jun 2007 22:26:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hopkins",
"Philip F.",
"",
"Harvard/CfA"
],
[
"Hernquist",
"Lars",
"",
"Harvard/CfA"
],
[
"Cox",
"Thomas J.",
"",
"Harvard/CfA"
],
[
"Keres",
"Dusan",
"",
"Harvard/CfA"
]
] |
0706.1244 | Paul Koerber | Paul Koerber and Dimitrios Tsimpis | Supersymmetric sources, integrability and generalized-structure
compactifications | 32 pages, 1 table, v2: added references, v3: corrected mistake in
(4.1) leading to factor 2 mistake in (B.6), corrected (B.5), smaller typos | JHEP 0708:082,2007 | 10.1088/1126-6708/2007/08/082 | MPP-2007-66, LMU-ASC 37/07 | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the context of supersymmetric compactifications of type II supergravity to
four dimensions, we show that orientifold sources can be compatible with a
generalized SU(3) x SU(3)-structure that is neither strictly SU(3) nor static
SU(2). We illustrate this with explicit examples, obtained by suitably
T-dualizing known solutions on the six-torus. In addition we prove the
following integrability statements, valid under certain mild assumptions: (a)
for general type II supergravity backgrounds with orientifold and/or D-brane
generalized-calibrated sources, the source-corrected Einstein and dilaton
equations of motion follow automatically from the supersymmetry equations once
the likewise source-corrected form equations of motion and Bianchi identities
are imposed; (b) in the special case of supersymmetric compactifications to
four-dimensional Minkowski space, the equations of motion of all fields,
including the NSNS three-form, follow automatically once the supersymmetry and
the Bianchi identities of the forms are imposed. Both (a) and (b) are equally
valid whether the sources are smeared or localized. As a byproduct we obtain
the calibration form for a space-filling NS5-brane.
| [
{
"version": "v1",
"created": "Sun, 10 Jun 2007 12:33:38 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 14:36:27 GMT"
},
{
"version": "v3",
"created": "Fri, 11 Jul 2008 09:48:27 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Koerber",
"Paul",
""
],
[
"Tsimpis",
"Dimitrios",
""
]
] |
0706.1245 | A. de Visser | N.T. Huy, D.E. de Nijs, A. Gasparini, J.C.P. Klaasse, A. de Visser,
N.H. van Dijk | Evidence for a ferromagnetic quantum critical point in URhGe doped with
Ru | 2 pages, conference paper, submitted to the proceedings of SCES'07 | Physica B 403 (2008) 1260-1261. | 10.1016/j.physb.2007.10.139 | null | cond-mat.str-el | null | We have investigated the evolution of ferromagnetic order in the correlated
metal series URh_{1-x}Ru_{x}Ge. Magnetization, transport and specific heat
measurements provide convincing evidence for a ferromagnetic quantum critical
point at the critical concentration x_{c} = 0.38. Here we report
ac-susceptibility and magnetization measurements on selected samples with Ru
doping concentrations near the critical point.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:06:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Huy",
"N. T.",
""
],
[
"de Nijs",
"D. E.",
""
],
[
"Gasparini",
"A.",
""
],
[
"Klaasse",
"J. C. P.",
""
],
[
"de Visser",
"A.",
""
],
[
"van Dijk",
"N. H.",
""
]
] |
0706.1246 | Philip Hopkins | Philip F. Hopkins, Thomas J. Cox, Dusan Keres, Lars Hernquist
(Harvard/CfA) | A Cosmological Framework for the Co-Evolution of Quasars, Supermassive
Black Holes, and Elliptical Galaxies: II. Formation of Red Ellipticals | 29 pages, 21 figures, submitted to ApJ. Replacement fixes comparison
of models in Figures 6 & 9 | Astrophys.J.Suppl. 175 (2008) 390-422 | 10.1086/524363 | null | astro-ph | null | (Abridged) We develop and test a model for the cosmological role of mergers
in the formation and quenching of red, early-type galaxies. Making the ansatz
that star formation is quenched after a gas-rich, spheroid-forming major
merger, we demonstrate that this naturally predicts the turnover in the
efficiency of star formation at ~L_star, as well as the observed mass
functions/density of red galaxies as a function of redshift, the formation
times of spheroids as a function of mass, and the fraction of quenched galaxies
as a function of galaxy and halo mass, environment, and redshift. Comparing to
a variety of semi-analytic models in which quenching is primarily driven by
halo mass considerations or secular/disk instabilities, we demonstrate that our
model and different broad classes of models make unique and robust qualitative
predictions for a number of observables, including the red fraction as a
function of galaxy and halo mass, the density of passive galaxies and evolution
of the color-morphology-density relations at high z, and the fraction of
disky/boxy spheroids as a function of mass. In each case, the observations
favor a model in which galaxies quench after a major merger builds a massive
spheroid, and disfavor quenching via secular or pure halo processes. We discuss
a variety of physical possibilities for this quenching, and propose a mixed
scenario in which traditional quenching in hot, massive halos is supplemented
by the feedback associated with star formation and quasar activity in a major
merger, which temporarily suppress cooling and establish the conditions of a
dynamically hot halo in the central regions of the host, even in low mass
halos.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:06:22 GMT"
},
{
"version": "v2",
"created": "Mon, 18 Jun 2007 22:27:26 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hopkins",
"Philip F.",
"",
"Harvard/CfA"
],
[
"Cox",
"Thomas J.",
"",
"Harvard/CfA"
],
[
"Keres",
"Dusan",
"",
"Harvard/CfA"
],
[
"Hernquist",
"Lars",
"",
"Harvard/CfA"
]
] |
0706.1247 | S\'ilvio Duarte Queir\'os M. | Silvio M. Duarte Queiros | Are all highly liquid securities within the same class? | To be published in EPJB | Eur. Phys. J. B 60, 265-269 (2007) | 10.1140/epjb/e2007-00336-7 | null | q-fin.ST physics.data-an physics.soc-ph | null | In this manuscript we analyse the leading statistical properties of
fluctuations of (log) 3-month US Treasury bill quotation in the secondary
market, namely: probability density function, autocorrelation, absolute values
autocorrelation, and absolute values persistency. We verify that this financial
instrument, in spite of its high liquidity, shows very peculiar properties.
Particularly, we verify that log-fluctuations belong to the Levy class of
stochastic variables.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:10:08 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 12:20:08 GMT"
}
] | 2008-12-02T00:00:00 | [
[
"Queiros",
"Silvio M. Duarte",
""
]
] |
0706.1248 | Pierre Sokolsky | P. Sokolsky (University of Utah), G.B. Thomson (Rutgers University) | Highest Energy Cosmic Rays and results from the HiRes Experiment | 31 pages, 18 figures, submitted to Journal of Physics G | J.Phys.G34:R401,2007 | 10.1088/0954-3899/34/11/R01 | null | astro-ph | null | The status of the field of ultrahigh energy cosmic rays is summarized, from
the point of view of the latest results of the High Resolution Fly's Eye
(HiRes) Experiment. HiRes results are presented, and compared with those of the
Akeno Giant Air Shower Array (AGASA), plus the Telescope Array and Pierre Auger
experiments. The HiRes measurements of the cosmic ray spectrum, and the
observation of the GZK cutoff are presented. HiRes results on composition,
searches for anisotropy, measurement of the proton-air total cross section, and
shapes of shower profiles are presented.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:13:59 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Sokolsky",
"P.",
"",
"University of Utah"
],
[
"Thomson",
"G. B.",
"",
"Rutgers University"
]
] |
0706.1249 | Jaiyeola Temitope Gbolahan | Temitope Gbolahan Jaiyeola | On The Universality Of Central Loops | 11 pages, submitted for publication | Acta Universitatis Apulensis Mathematics-Informatics, Vol.
19(2009), 113-124. | null | null | math.GM | null | LC-loops, RC-loops and C-loops are collectively called central loops. It is
shown that an LC(RC)-loop is a left(right) universal loop. But an LC(RC)-loop
is a universal loop if and only if it is a right(left) universal loop. It is
observed that not all RC-loops or LC-loops or C-loops are universal loops. But
if an RC-loop(LC-loop, C-loop) is universal, then it is a right Bol loop(left
Bol loop, Moufang loop) respectively. If a loop and its right or left isotope
are commutative then the loop is a C-loop if and only if its right or left
isotope is a C-loop. If a C-loop is central square and its right or left
isotope is an alternative central square loop, then the latter is a C-loop.
Necessary and sufficient condition for an LC-loop(RC-loop) to be a
left(right)G-loop is established. Consequently, necessary and sufficient
conditions for an LC-loop, and an RC-loop to be a G-loop are established. A
necessary and sufficient condition for a C-loop to be a G-loop is established.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 14:03:20 GMT"
},
{
"version": "v2",
"created": "Mon, 11 Feb 2008 11:18:24 GMT"
}
] | 2010-03-05T00:00:00 | [
[
"Jaiyeola",
"Temitope Gbolahan",
""
]
] |
0706.1250 | Paulsamy Muruganandam | Paulsamy Muruganandam, Fernando F. Ferreira, Hassan F. El-Nashar,
Hilda A. Cerdeira | Analytical calculation of the transition to complete phase
synchronization in coupled oscillators | 5 pages, 3 figures | Pramana J. Phys. 70 (2008) 1143-1151 | 10.1007/s12043-008-0119-8 | null | nlin.CD | null | Here we present a system of coupled phase oscillators with nearest neighbors
coupling, which we study for different boundary conditions. We concentrate at
the transition to total synchronization. We are able to develop exact solutions
for the value of the coupling parameter when the system becomes completely
synchronized, for the case of periodic boundary conditions as well as for an
open chain with fixed ends. We compare the results with those calculated
numerically.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:25:42 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 01:05:22 GMT"
}
] | 2011-11-28T00:00:00 | [
[
"Muruganandam",
"Paulsamy",
""
],
[
"Ferreira",
"Fernando F.",
""
],
[
"El-Nashar",
"Hassan F.",
""
],
[
"Cerdeira",
"Hilda A.",
""
]
] |
0706.1251 | Javier L. Albacete | Javier L. Albacete | Multiplicities in Pb-Pb central collisions at the LHC from running
coupling evolution and RHIC data | 1 figure replaced. References updated | null | null | null | hep-ph | null | Predictions for the pseudorapidity density of charged particles produced in
Pb-Pb central collisions at $\sqrt{s_{NN}}=5.5$ TeV are presented. Particle
production in such collisions is computed in the framework of
k_t-factorization, using running coupling non-linear evolution to determine the
transverse momentum and rapidity dependence of the nuclear unintegrated gluon
distributions.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:31:10 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 16:04:02 GMT"
}
] | 2007-07-18T00:00:00 | [
[
"Albacete",
"Javier L.",
""
]
] |
0706.1252 | Jeffrey Sokoloff | J. B. Sokoloff | Theory of the Observed Ultra-Low Friction between Sliding
Polyelectrolyte Brushes | latex with 2 figures as eps files. Revised version has an improved
solution to the Poisson-Boltzmann equation | null | 10.1063/1.2948412 | null | cond-mat.mtrl-sci cond-mat.soft | null | It is shown using a method based on a modified version of the mean field
theory of Miklavic Marcelja that it should be possible for osmotic pressure due
to the counterions associated with the two polyelectrolyte polymer brush coated
surfaces to support a reasonable load (i.e., about $10^6 Pa$) with the brushes
held sufficiently far apart to prevent entanglement of polymers belonging to
the two brushes, thus avoiding what is believed to be the dominant mechanisms
for static and dry friction.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:31:48 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Dec 2007 17:11:26 GMT"
},
{
"version": "v3",
"created": "Wed, 28 May 2008 21:59:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sokoloff",
"J. B.",
""
]
] |
0706.1253 | Wei Zhang | Wei Zhang and L.-M. Duan | Finite temperature phase diagram of trapped Fermi gases with population
imbalance | 9 pages, 7 figures | Phys. Rev. A 76, 042710 (2007) | 10.1103/PhysRevA.76.042710 | null | cond-mat.str-el cond-mat.supr-con | null | We consider a trapped Fermi gas with population imbalance at finite
temperatures and map out the detailed phase diagram across a wide Feshbach
resonance. We take the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state into
consideration and minimize the thermodynamical potential to ensure stability.
Under the local density approximation, we conclude that a stable LOFF state is
present only on the BCS side of the Feshbach resonance, but not on the BEC side
or at unitarity. Furthermore, even on the BCS side, a LOFF state is restricted
at low temperatures and in a small region of the trap, which makes a direct
observation of LOFF state a challenging task.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:50:01 GMT"
},
{
"version": "v2",
"created": "Wed, 21 May 2008 16:42:17 GMT"
}
] | 2008-05-21T00:00:00 | [
[
"Zhang",
"Wei",
""
],
[
"Duan",
"L. -M.",
""
]
] |
0706.1254 | Andrea Zoia | A. Zoia, A. Rosso, M. Kardar | Fractional Laplacian in Bounded Domains | 11 pages, 11 figures | PHYSICAL REVIEW E 76, 021116 (2007) | 10.1103/PhysRevE.76.021116 | null | cond-mat.stat-mech | null | The fractional Laplacian operator, $-(-\triangle)^{\frac{\alpha}{2}}$,
appears in a wide class of physical systems, including L\'evy flights and
stochastic interfaces. In this paper, we provide a discretized version of this
operator which is well suited to deal with boundary conditions on a finite
interval. The implementation of boundary conditions is justified by appealing
to two physical models, namely hopping particles and elastic springs. The
eigenvalues and eigenfunctions in a bounded domain are then obtained
numerically for different boundary conditions. Some analytical results
concerning the structure of the eigenvalues spectrum are also obtained.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:51:47 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Zoia",
"A.",
""
],
[
"Rosso",
"A.",
""
],
[
"Kardar",
"M.",
""
]
] |
0706.1255 | Cynthia Aku-Leh | Cynthia Aku-Leh, Florent Perez, Bernard Jusserand, David Richards,
Wojciech Pacuski, Piotr Kossacki, Michel Menant and Grzegorz Karczewski | Measuring the spin polarization and Zeeman energy of a spin-polarized
electron gas: Comparison between Raman scattering and photoluminescence | 13 pages, 11 figures, 1 table, submitted to Phys. Rev. B | null | 10.1103/PhysRevB.76.155416 | null | cond-mat.other cond-mat.mtrl-sci | null | We compare resonant electronic Raman scattering and photoluminescence
measurements for the characterization of a spin-polarized two-dimensional
electron gas embedded in $\text{Cd}_{1-x}\text{Mn}_x\text{Te}$ single quantum
wells. From Raman scattering by single-particle excitations in a zero magnetic
field, we measure the Fermi velocity and then obtain the Fermi energy (as well
as the electron density), which is comparable to that extracted from
photoluminescence for moderate electron densities, assuming a bare band-edge
mass. At large electron densities, the Fermi energies derived from Raman
scattering and photoluminescence differ. For an applied in-plane magnetic field
and zero wave vector transferred to the electron gas, Raman scattering spectra
show peaks at both the Zeeman energy $Z$, resulting from collective excitations
of the spin-polarized electron gas, and the one electron spin-flip energy
$Z^*$. Magneto-photoluminescence spectra show conduction band splitting that
are equivalent to $Z$, suggesting that collective effects are present in the
photoluminescence spectra. Assuming (as before) an uncorrected mass, the degree
of spin polarization $\zeta$ determined from the magneto-photoluminescence
lineshape is found to differ from that derived from the magnetic field
dependent Raman scattering measurements for large electron densities. We
attribute the discrepancy in measuring $\zeta$ and the Fermi energy to the
renormalized mass resulting from many-body electron-electron interactions.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 20:58:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Aku-Leh",
"Cynthia",
""
],
[
"Perez",
"Florent",
""
],
[
"Jusserand",
"Bernard",
""
],
[
"Richards",
"David",
""
],
[
"Pacuski",
"Wojciech",
""
],
[
"Kossacki",
"Piotr",
""
],
[
"Menant",
"Michel",
""
],
[
"Karczewski",
"Grzegorz",
""
]
] |
0706.1256 | Xavier Bertou | X.Bertou (for the Pierre Auger Observatory) | Search for Gamma Ray Bursts using the single particle technique at the
Pierre Auger Observatory | 4 pages, 4 figures. To be published in Proceedings of the 30th
International Cosmic Ray Conference, July 3 - 11, 2007, Merida, Yucatan,
Mexico | null | null | null | astro-ph | null | The Pierre Auger Observatory, with an array of currently more than 1200
Cherenkov detectors filled with 12 m$^3$ of water, can detect the putative high
energy emission of a GRB (photons down to a few hundreds of MeV) by the
so-called ``single particle technique'', through a coherent increase in the
average background particle rates over the whole array, due to secondary
particles in the photon-induced showers. We present a search for bursts on data
collected since September 2005, as well as a search for excesses in coincidence
with bursts observed by satellites.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:00:32 GMT"
}
] | 2019-08-14T00:00:00 | [
[
"Bertou",
"X.",
"",
"for the Pierre Auger Observatory"
]
] |
0706.1257 | Alma Ruiz Velasco E. | A. E. Ruiz-Velasco, H. Swan, E. Troja, D. Malesani, J. P. U. Fynbo, R.
L. C. Starling, D. Xu, F. Aharonian, C. Akerlof, M. I. Andersen, M. C. B.
Ashley, S. D. Barthelmy, D. Bersier, J. M. Castro Cer\'on, A. J.
Castro-Tirado, N. Gehrels, E. G\"o\u{g}\"u\c{s}, J. Gorosabel, C. Guidorzi,
T. G\"uver, J. Hjorth, D. Horns, K. Y. Huang, P. Jakobsson, B. L. Jensen,
\"U. K{\i}z{\i}lo\v{g}lu, C. Kouveliotou, H. A. Krimm, C. Ledoux, A. J.
Levan, T. Marsh, T. McKay, A. Melandri, B. Milvang-Jensen, C. G. Mundell, P.
T. O'Brien, M. \"Ozel, A. Phillips, R. Quimby, G. Rowell, W. Rujopakarn, E.
S. Rykoff, B. E. Schaefer, J. Sollerman, N. R. Tanvir, C. C. Th\"one, Y.
Urata, W. T. Vestrand, P. M. Vreeswijk, D. Watson, J. C. Wheeler, R. A. M. J.
Wijers, J. Wren, S. A. Yost, F. Yuan, M. Zhai, W. K. Zheng | Detection of GRB 060927 at z = 5.47: Implications for the Use of
Gamma-Ray Bursts as Probes of the End of the Dark Ages | 15 pages, 6 figures, 2 tables, accepted for publication in ApJ, uses
emulateapj | Astrophys.J. 669 (2007) 1-9 | 10.1086/521546 | null | astro-ph | null | We report on follow-up observations of the GRB 060927 using the ROTSE-IIIa
telescope and a suite of larger aperture ground-based telescopes. An optical
afterglow was detected 20 s after the burst, the earliest rest-frame detection
of optical emission from any GRB. Spectroscopy performed with the VLT about 13
hours after the trigger shows a continuum break at lambda ~ 8070 A produced by
neutral hydrogen absorption at z~5.6. We also detect an absorption line at 8158
A which we interpret as SiII at z=5.467. Hence, GRB 060927 is the second most
distant GRB with a spectroscopically measured redshift. The shape of the red
wing of the spectral break can be fitted by a damped Lyalpha profile with a
column density with log(N_HI/cm^-2) ~ 22.5. We discuss the implications of this
work for the use of GRBs as probes of the end of the dark ages and draw three
main conclusions: i) GRB afterglows originating from z>6 should be relatively
easy to detect from the ground, but rapid NIR monitoring is necessary to ensure
that they are found; ii) The presence of large HI column densities in some GRBs
host galaxies at z>5 makes the use of GRBs to probe the reionization epoch via
spectroscopy of the red damping wing challenging; iii) GRBs appear crucial to
locate typical star-forming galaxies at z>5 and therefore the type of galaxies
responsible for the reionization of the universe.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 15:05:29 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 13:28:46 GMT"
}
] | 2008-04-14T00:00:00 | [
[
"Ruiz-Velasco",
"A. E.",
""
],
[
"Swan",
"H.",
""
],
[
"Troja",
"E.",
""
],
[
"Malesani",
"D.",
""
],
[
"Fynbo",
"J. P. U.",
""
],
[
"Starling",
"R. L. C.",
""
],
[
"Xu",
"D.",
""
],
[
"Aharonian",
"F.",
""
],
[
"Akerlof",
"C.",
""
],
[
"Andersen",
"M. I.",
""
],
[
"Ashley",
"M. C. B.",
""
],
[
"Barthelmy",
"S. D.",
""
],
[
"Bersier",
"D.",
""
],
[
"Cerón",
"J. M. Castro",
""
],
[
"Castro-Tirado",
"A. J.",
""
],
[
"Gehrels",
"N.",
""
],
[
"Göğüş",
"E.",
""
],
[
"Gorosabel",
"J.",
""
],
[
"Guidorzi",
"C.",
""
],
[
"Güver",
"T.",
""
],
[
"Hjorth",
"J.",
""
],
[
"Horns",
"D.",
""
],
[
"Huang",
"K. Y.",
""
],
[
"Jakobsson",
"P.",
""
],
[
"Jensen",
"B. L.",
""
],
[
"Kızıloǧlu",
"Ü.",
""
],
[
"Kouveliotou",
"C.",
""
],
[
"Krimm",
"H. A.",
""
],
[
"Ledoux",
"C.",
""
],
[
"Levan",
"A. J.",
""
],
[
"Marsh",
"T.",
""
],
[
"McKay",
"T.",
""
],
[
"Melandri",
"A.",
""
],
[
"Milvang-Jensen",
"B.",
""
],
[
"Mundell",
"C. G.",
""
],
[
"O'Brien",
"P. T.",
""
],
[
"Özel",
"M.",
""
],
[
"Phillips",
"A.",
""
],
[
"Quimby",
"R.",
""
],
[
"Rowell",
"G.",
""
],
[
"Rujopakarn",
"W.",
""
],
[
"Rykoff",
"E. S.",
""
],
[
"Schaefer",
"B. E.",
""
],
[
"Sollerman",
"J.",
""
],
[
"Tanvir",
"N. R.",
""
],
[
"Thöne",
"C. C.",
""
],
[
"Urata",
"Y.",
""
],
[
"Vestrand",
"W. T.",
""
],
[
"Vreeswijk",
"P. M.",
""
],
[
"Watson",
"D.",
""
],
[
"Wheeler",
"J. C.",
""
],
[
"Wijers",
"R. A. M. J.",
""
],
[
"Wren",
"J.",
""
],
[
"Yost",
"S. A.",
""
],
[
"Yuan",
"F.",
""
],
[
"Zhai",
"M.",
""
],
[
"Zheng",
"W. K.",
""
]
] |
0706.1258 | Frank Reifler | Frank Reifler and Randall Morris | Hestenes' Tetrad and Spin Connections | null | Int.J.Theor.Phys.44:1307-1324,2005 | 10.1007/s10773-005-4688-8 | null | gr-qc math-ph math.MP quant-ph | null | Defining a spin connection is necessary for formulating Dirac's bispinor
equation in a curved space-time. Hestenes has shown that a bispinor field is
equivalent to an orthonormal tetrad of vector fields together with a complex
scalar field. In this paper, we show that using Hestenes' tetrad for the spin
connection in a Riemannian space-time leads to a Yang-Mills formulation of the
Dirac Lagrangian in which the bispinor field is mapped to a set of Yang-Mills
gauge potentials and a complex scalar field. This result was previously proved
for a Minkowski space-time using Fierz identities. As an application we derive
several different non-Riemannian spin connections found in the literature
directly from an arbitrary linear connection acting on Hestenes' tetrad and
scalar fields. We also derive spin connections for which Dirac's bispinor
equation is form invariant. Previous work has not considered form invariance of
the Dirac equation as a criterion for defining a general spin connection.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:21:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Reifler",
"Frank",
""
],
[
"Morris",
"Randall",
""
]
] |
0706.1259 | Sang Jo | E. Akofor, A. P. Balachandran, S. G. Jo and A. Joseph | Quantum Fields on the Groenewold-Moyal Plane: C, P, T and CPT | 18 pages, 1 figure, revised, 2 references added | JHEP 0708:045,2007 | 10.1088/1126-6708/2007/08/045 | null | hep-th gr-qc hep-ph math.QA | null | We show that despite the inherent non-locality of quantum field theories on
the Groenewold-Moyal (GM) plane, one can find a class of ${\bf C}$, ${\bf P}$,
${\bf T}$ and ${\bf CPT}$ invariant theories. In particular, these are theories
without gauge fields or with just gauge fields and no matter fields. We also
show that in the presence of gauge fields, one can have a field theory where
the Hamiltonian is ${\bf C}$ and ${\bf T}$ invariant while the $S$-matrix
violates ${\bf P}$ and ${\bf CPT}$.
In non-abelian gauge theories with matter fields such as the electro-weak and
$QCD$ sectors of the standard model of particle physics, ${\bf C}$, ${\bf P}$,
${\bf T}$ and the product of any pair of them are broken while ${\bf CPT}$
remains intact for the case $\theta^{0i} =0$. (Here $x^{\mu} \star x^{\nu} -
x^{\nu} \star x^{\mu} = i \theta^{\mu \nu}$, $x^{\mu}$: coordinate functions,
$\theta^{\mu \nu} = -\theta^{\nu \mu}=$ constant.) When $\theta^{0i} \neq 0$,
it contributes to breaking also ${\bf P}$ and ${\bf CPT}$. It is known that the
$S$-matrix in a non-abelian theory depends on $\theta^{\mu \nu}$ only through
$\theta^{0i}$. The $S$-matrix is frame dependent. It breaks (the identity
component of the) Lorentz group. All the noncommutative effects vanish if the
scattering takes place in the center-of-mass frame, or any frame where
$\theta^{0i}P^{\textrm{in}}_{i} = 0$, but not otherwise. ${\bf P}$ and ${\bf
CPT}$ are good symmetries of the theory in this special case.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:27:32 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Jun 2007 14:43:18 GMT"
},
{
"version": "v3",
"created": "Tue, 24 Jul 2007 15:31:07 GMT"
},
{
"version": "v4",
"created": "Thu, 26 Jul 2007 16:08:47 GMT"
},
{
"version": "v5",
"created": "Thu, 4 Oct 2007 06:37:30 GMT"
}
] | 2009-05-20T00:00:00 | [
[
"Akofor",
"E.",
""
],
[
"Balachandran",
"A. P.",
""
],
[
"Jo",
"S. G.",
""
],
[
"Joseph",
"A.",
""
]
] |
0706.1260 | Rogerio de Sousa | Rogerio de Sousa and Joel E. Moore | Optical coupling to spin waves in the cycloidal multiferroic BiFeO3 | Final published version | Phys. Rev. B 77, 012406 (2008) | 10.1103/PhysRevB.77.012406 | null | cond-mat.str-el cond-mat.mtrl-sci cond-mat.stat-mech | null | The magnon and optical phonon spectrum of an incommensurate multiferroic such
as BiFeO3 is considered in the framework of a phenomenological Landau theory.
The resulting spin wave spectrum is quite distinct from commensurate substances
due to soft mode anisotropy and magnon zone folding. The former allows
electrical control of spin wave propagation via reorientation of the
spontaneous ferroelectric moment. The latter gives rise to multiple
magneto-dielectric resonances due to the coupling of optical phonons at zero
wavevector to magnons at integer multiples of the cycloid wavevector. These
results show that the optical response of a multiferroic reveals much more
about its magnetic excitations than previously anticipated on the basis of
simpler models.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:32:49 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 17:42:43 GMT"
},
{
"version": "v3",
"created": "Wed, 23 Jan 2008 22:17:27 GMT"
}
] | 2008-01-24T00:00:00 | [
[
"de Sousa",
"Rogerio",
""
],
[
"Moore",
"Joel E.",
""
]
] |
0706.1261 | Stefan Tsonchev | Stefan Tsonchev, Rob D. Coalson, and Anthony Duncan | Partitioning of a polymer chain between a confining cavity and a gel | 17 pages, 6 figures | null | 10.1103/PhysRevE.76.041804 | null | cond-mat.stat-mech cond-mat.soft | null | A lattice field theory approach to the statistical mechanics of charged
polymers in electrolyte solutions [S. Tsonchev, R. D. Coalson, and A. Duncan,
Phys. Rev. E 60, 4257, (1999)] is applied to the study of a polymer chain
contained in a spherical cavity but able to diffuse into a surrounding gel. The
distribution of the polymer chain between the cavity and the gel is described
by its partition coefficient, which is computed as a function of the number of
monomers in the chain, the monomer charge, and the ion concentrations in the
solution.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:34:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tsonchev",
"Stefan",
""
],
[
"Coalson",
"Rob D.",
""
],
[
"Duncan",
"Anthony",
""
]
] |
0706.1262 | Keh-Fei Liu | Keh-Fei Liu | Pattern of Light Scalar Mesons | 8 pages, 4 figures | Prog.Theor.Phys.Suppl.168:160-167,2007 | 10.1143/PTPS.168.160 | null | hep-ph hep-lat nucl-th | null | Combining the recent lattice calculation of $a_0(1450)$ and $\sigma(600)$
mesons with the overlap fermion in the chiral regime with the pion mass less
than $300 {\rm MeV}$, the quenched lattice calculation of the scalar glueball,
and the phenomenological study of the mixing of isoscalar scalar mesons
$f_0(1710)$, $f_0(1500)$, $f_0(1370)$ through their decays, a simple pattern
for the light scalar mesons begins to emerge. Below 1 GeV, the scalar mesons
form a nonet of tetraquark mesoniums. Above 1 GeV, the nonent $q\bar{q}$ mesons
are made of an octet with largely unbroken SU(3) symmetry and a fairly good
singlet which is $f_0(1370)$. $f_0(1710)$ is identified as an almost pure
scalar glueball with a $\sim 10%$ mixture of $q\bar{q}$.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:39:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liu",
"Keh-Fei",
""
]
] |
0706.1263 | Igor Nikolaev | Igor Nikolaev | Remark on the rank of elliptic curves | 13 pages, 2 figures; to appear Osaka J. Mathematics 46 (2009), No.2;
http://projecteuclid.org/euclid.ojm/1245415682 | Osaka J. Math. 46 (2009), 515--527 | null | null | math.NT math.OA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A covariant functor on the elliptic curves with complex multiplication is
constructed. The functor takes values in the noncommutative tori with real
multiplication. A conjecture on the rank of an elliptic curve is formulated.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 21:40:40 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 17:51:47 GMT"
},
{
"version": "v3",
"created": "Sun, 13 Apr 2008 20:18:58 GMT"
},
{
"version": "v4",
"created": "Thu, 8 Jan 2009 16:29:33 GMT"
}
] | 2009-06-22T00:00:00 | [
[
"Nikolaev",
"Igor",
""
]
] |
0706.1264 | Mark G. Jackson | Mark G. Jackson | Interactions of Cosmic Superstrings | 22 pages, 6 figures; v2: updated references | JHEP 0709:035,2007 | 10.1088/1126-6708/2007/09/035 | FERMILAB-PUB-07-187-A | hep-th astro-ph gr-qc | null | We develop methods by which cosmic superstring interactions can be studied in
detail. These include the reconnection probability and emission of radiation
such as gravitons or small string loops. Loop corrections to these are
discussed, as well as relationships to $(p,q)$-strings. These tools should
allow a phenomenological study of string models in anticipation of upcoming
experiments sensitive to cosmic string radiation.
| [
{
"version": "v1",
"created": "Sun, 10 Jun 2007 17:16:37 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Sep 2007 20:43:53 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Jackson",
"Mark G.",
""
]
] |
0706.1265 | Joseph Rhee | Joseph H. Rhee, Inseok Song, B. Zuckerman | EF Cha: Warm Dust Orbiting a Nearby 10 Myr Old Star | New Spitzer MIPS data added; 14 pages, 1 figure, ApJ in press | null | 10.1086/520760 | null | astro-ph | null | Most Vega-like stars have far-infrared excess (60micron or longward in IRAS,
ISO, or Spitzer MIPS bands) and contain cold dust (<~150K) analogous to the
Sun's Kuiper-Belt region. However, dust in a region more akin to our asteroid
belt and thus relevant to the terrestrial planet building process is warm and
produces excess emission in mid-infrared wavelengths. By cross-correlating
Hipparcos dwarfs with the MSX catalog, we found that EF Cha, a member of the
recently identified, ~10 Myr old, ``Cha-Near'' Moving Group, possesses
prominent mid-infrared excess. N-band spectroscopy reveals a strong emission
feature characterized by a mixture of small, warm, amorphous and possibly
crystalline silicate grains. Survival time of warm dust grains around this A9
star is <~ 1E5 yrs, much less than the age of the star. Thus, grains in this
extra-solar terrestrial planetary zone must be of "second generation" and not a
remnant of primodial dust and are suggestive of substantial planet formation
activity. Such second generation warm excess occurs around ~ 13% of the
early-type stars in nearby young stellar associations.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 22:05:08 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 23:05:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rhee",
"Joseph H.",
""
],
[
"Song",
"Inseok",
""
],
[
"Zuckerman",
"B.",
""
]
] |
0706.1266 | Jan Kurzyk | Jan Kurzyk, Jozef Spa{\l}ek, W{\l}odzimierz W\'ojcik | Lieb-Wu Solution, Gutzwiller-Wave-Function, and Gutzwiller-Ansatz
Approximation, with Adjustable Single-Particle Wave Function for the Hubbard
Chain | 17 pages, 8 figures, 2 tables | Acta Physica Polonica A 111, 603 (2007) | null | null | cond-mat.str-el | null | The optimized single-particle wave functions contained in the parameters of
the Hubbard model (t and U) were determined for an infinite atomic chain. In
effect, the electronic properties of the chain as a function of interatomic
distance R were obtained and compared for the Lieb - Wu exact solution (LW),
the Gutzwiller-Wave-Function approximation (GWF), and the Gutzwiller-ansatz
case (GA). The ground state energy and other characteristics for the infinite
chain were also compared with those obtained earlier for a nanoscopic chain
within the Exact Diagonalization combined with an Ab Initio adjustment of the
single-particle wave functions in the correlated state (EDABI method). For the
sake of completeness, we briefly characterize also each of the solutions. Our
approach completes the Lieb-Wu solution, as it provides the system electronic
properties evolution as a function of physically controllable parameter - the
interatomic distance.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 06:53:53 GMT"
}
] | 2007-06-25T00:00:00 | [
[
"Kurzyk",
"Jan",
""
],
[
"Spałek",
"Jozef",
""
],
[
"Wójcik",
"Włodzimierz",
""
]
] |
0706.1267 | Jan Soubusta | J. Soubusta, L. Bartuskova, A. Cernoch, J. Fiurasek, M. Dusek | Several experimental realizations of symmetric phase-covariant quantum
cloner of single-photon qubits | 8 pages, 11 figures | Phys. Rev. A 76, 042318 (2007) | 10.1103/PhysRevA.76.042318 | null | quant-ph | null | We compare several optical implementations of phase-covariant cloning
machines. The experiments are based on copying of the polarization state of a
single photon in bulk optics by special unbalanced beam splitter or by balanced
beam splitter accompanied by a state filtering. Also the all-fiber based setup
is discussed, where the information is encoded into spatial modes, i.e., the
photon can propagate through two optical fibers. Each of the four
implementations possesses some advantages and disadvantages that are discussed.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 22:32:58 GMT"
}
] | 2008-04-04T00:00:00 | [
[
"Soubusta",
"J.",
""
],
[
"Bartuskova",
"L.",
""
],
[
"Cernoch",
"A.",
""
],
[
"Fiurasek",
"J.",
""
],
[
"Dusek",
"M.",
""
]
] |
0706.1268 | Shashank Misra | S. Misra, N. C. Bishop, E. Tutuc, M. Shayegan | Tunneling between Dilute GaAs Hole Layers | Revised to include additional data, new discussions | null | 10.1103/PhysRevB.77.161301 | null | cond-mat.mes-hall | null | We report interlayer tunneling measurements between very dilute
two-dimensional GaAs hole layers. Surprisingly, the shape and
temperature-dependence of the tunneling spectrum can be explained with a Fermi
liquid-based tunneling model, but the peak amplitude is much larger than
expected from the available hole band parameters. Data as a function of
parallel magnetic field reveal additional anomalous features, including a
recurrence of a zero-bias tunneling peak at very large fields. In a
perpendicular magnetic field, we observe a robust and narrow tunneling peak at
total filling factor $\nu_T=1$, signaling the formation of a bilayer quantum
Hall ferromagnet.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 00:09:45 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Oct 2007 22:06:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Misra",
"S.",
""
],
[
"Bishop",
"N. C.",
""
],
[
"Tutuc",
"E.",
""
],
[
"Shayegan",
"M.",
""
]
] |
0706.1269 | Francesco Nitti | E. Dudas, J. Mourad, F. Nitti | Metastable Vacua in Brane Worlds | LaTeX, 24 pages | JHEP 0708:057,2007 | 10.1088/1126-6708/2007/08/057 | null | hep-th hep-ph | null | We analyze vacuum decay in brane world setups, where a free scalar field in
five dimensions has a localized potential admitting metastable vacua. We study
in particular the bounce solution and its properties in flat and warped spaces.
In the latter case, placing into a deeply warped region the term in the
potential that lifts the vacuum degeneracy, can increase indefinitely the
lifetime of the false vacuum. We discuss the application to metastable vacua in
supersymmetric brane-world constructions.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 22:57:48 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Dudas",
"E.",
""
],
[
"Mourad",
"J.",
""
],
[
"Nitti",
"F.",
""
]
] |
0706.1270 | Katrin Heitmann | Katrin Heitmann, Zarija Lukic, Patricia Fasel, Salman Habib, Michael
S. Warren, Martin White, James Ahrens, Lee Ankeny, Ryan Armstrong, Brian
O'Shea, Paul M. Ricker, Volker Springel, Joachim Stadel, Hy Trac | The Cosmic Code Comparison Project | 28 pages, 14 figures | Comput.Sci.Dis.1:015003,2008 | 10.1088/1749-4699/1/1/015003 | LA-UR-07-1953 | astro-ph | null | Current and upcoming cosmological observations allow us to probe structures
on smaller and smaller scales, entering highly nonlinear regimes. In order to
obtain theoretical predictions in these regimes, large cosmological simulations
have to be carried out. The promised high accuracy from observations make the
simulation task very demanding: the simulations have to be at least as accurate
as the observations. This requirement can only be fulfilled by carrying out an
extensive code validation program. The first step of such a program is the
comparison of different cosmology codes including gravitation interactions
only. In this paper we extend a recently carried out code comparison project to
include five more simulation codes. We restrict our analysis to a small
cosmological volume which allows us to investigate properties of halos. For the
matter power spectrum and the mass function, the previous results hold, with
the codes agreeing at the 10% level over wide dynamic ranges. We extend our
analysis to the comparison of halo profiles and investigate the halo count as a
function of local density. We introduce and discuss ParaView as a flexible
analysis tool for cosmological simulations, the use of which immensely
simplifies the code comparison task.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 22:43:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Heitmann",
"Katrin",
""
],
[
"Lukic",
"Zarija",
""
],
[
"Fasel",
"Patricia",
""
],
[
"Habib",
"Salman",
""
],
[
"Warren",
"Michael S.",
""
],
[
"White",
"Martin",
""
],
[
"Ahrens",
"James",
""
],
[
"Ankeny",
"Lee",
""
],
[
"Armstrong",
"Ryan",
""
],
[
"O'Shea",
"Brian",
""
],
[
"Ricker",
"Paul M.",
""
],
[
"Springel",
"Volker",
""
],
[
"Stadel",
"Joachim",
""
],
[
"Trac",
"Hy",
""
]
] |
0706.1271 | Eduard Alexis Larranaga Rubio | Alexis Larranaga | Agujeros de Gusano en Gravedad (2+1) | 22 pages, in Spanish | null | null | null | gr-qc | null | Traversable wormholes are objects that present a lot of interest in the last
years because of their geometric features and their relation with exotic
matter. In this paper we presnt a review of the principal characteristics of
traversable Morris-Thorne wormholes, their construction proccess and some
aspects about the exotic matter that is needed in order to mantain them. Then,
we use a junction proccess to obatin two specific wormhole solutions in the
(2+1) gravity formalism with negative cosmological constant. The obtained
solutions represent wormholes with an external spacetime correspondient to the
BTZ black hole solution. We also show that exotic matter is needed to mantain
these wormholes.
-----
Los agujeros de gusano atravesables son objetos que presentan un gran interes
en la actualidad debido a sus caracteristicas geometricas y a su relacion con
la materia exotica. En el presente trabajo se muestra una revision de las
caracteristicas de los agujeros de gusano atravesables al estilo de Morris y
Thorne, al igual que el proceso de construccion y aspectos de la materia
exotica necesaria para mantenerlos. Luego, se utiliza un proceso de juntura
para construir dos soluciones especificas tipo agujero de gusano en el
formalismo de la gravedad (2+1) con constante cosmologica negativa. Con esta
construccion, se obtienen agujeros atravesables que se encuentran unidos a un
espacio-tiempo externo correspondiente al agujero negro BTZ sin momento angular
y sin carga electrica. Ademas de esto, se muestra que para mantener este tipo
de solucion es necesaria la existencia de materia exotica, es decir, materia
que viole las condiciones de energia.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 22:47:30 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 13:30:44 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Larranaga",
"Alexis",
""
]
] |
0706.1272 | Katherine Kretke | Katherine A. Kretke, D. N. C. Lin | Grain Retention and Formation of Planetesimals near the Snow Line in
MRI-driven Turbulent Protoplanetary Disks | 12 pages in preprint format, 2 figures, accepted ApJ Letters | null | 10.1086/520718 | null | astro-ph | null | The first challenge in the formation of both terrestrial planets and the
cores of gas giants is the retention of grains in protoplanetary disks. In most
regions of these disks, gas attains sub-Keplerian speeds as a consequence of a
negative pressure gradient. Hydrodynamic drag leads to orbital decay and
depletion of the solid material in the disk, with characteristic timescales as
short as only a few hundred years for meter-sized objects at 1 AU. In this
paper, we suggest a particle retention mechanism which promotes the
accumulation of grains and the formation of planetesimals near the water
sublimation front or ``snow line.'' This model is based on the assumption that,
in the regions most interesting for planet formation, the viscous evolution of
the disk is due to turbulence driven by the magneto-rotational instability
(MRI) in the surface layers of the disk. The depth to which MRI effectively
generates turbulence is a strong function of the grain size and abundance. A
sharp increase in the grain-to-gas density ratio across the snow line reduces
the column depth of the active layer. As the disk evolves towards a
quasi-steady-state, this change in the active layer creates a local maximum in
radial distribution of the gas surface density and pressure, causing the gas to
rotate at super-Keplerian speed and halting the inward migration of grains.
This senario presents a robust process for grain retention which may aid in the
formation of proto-gas-giant cores preferentially near the snow line.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 22:54:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kretke",
"Katherine A.",
""
],
[
"Lin",
"D. N. C.",
""
]
] |
0706.1273 | Daniele Malesani | D. Malesani, S. Covino, P. D'Avanzo, V. D'Elia, D. Fugazza, S.
Piranomonte, L. Ballo, S. Campana, L. Stella, G. Tagliaferri, L. A.
Antonelli, G. Chincarini, M. Della Valle, P. Goldoni, C. Guidorzi, G. L.
Israel, D. Lazzati, A. Melandri, L. J. Pellizza, P. Romano, G. Stratta, S. D.
Vergani | Multicolor observations of the afterglow of the short/hard GRB 050724 | 8 pages, 5 figures, 4 tables, accepted for publication in A&A, typo
fixed | Astron.Astrophys. 473 (2007) 77-84 | 10.1051/0004-6361:20077868 | null | astro-ph | null | New information on short/hard gamma-ray bursts (GRBs) is being gathered
thanks to the discovery of their optical and X-ray afterglows. However, some
key aspects are still poorly understood, including the collimation level of the
outflow, the duration of the central engine activity, and the properties of the
progenitor systems. We want to constrain the physical properties of the short
GRB 050724 and of its host galaxy, and make some inferences on the global short
GRB population. We present optical observations of the afterglow of GRB 050724
and of its host galaxy, significantly expanding the existing dataset for this
event. We compare our results with models, complementing them with available
measurements from the literature. We study the afterglow light curve and
spectrum including X-ray data. We also present observations of the host galaxy.
The observed optical emission was likely related to the large flare observed in
the X-ray light curve. The apparent steep decay was therefore not due to the
jet effect. Available data are indeed consistent with low collimation, in turn
implying a large energy release, comparable to that of long GRBs. The flare
properties also constrain the internal shock mechanism, requiring a large
Lorentz factor contrast between the colliding shells. This implies that the
central engine was active at late times, rather than ejecting all shells
simultaneously. The host galaxy has red colors and no ongoing star formation,
consistent with previous findings on this GRB. However, it is not a pure
elliptical, and has some faint spiral structure. GRB 050724 provides the most
compelling case for association between a short burst and a galaxy with old
stellar population. It thus plays a pivotal role in constraining progenitors
models, which should allow for long delays between birth and explosion.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 23:08:14 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jul 2007 17:29:31 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Sep 2007 19:21:05 GMT"
}
] | 2007-10-03T00:00:00 | [
[
"Malesani",
"D.",
""
],
[
"Covino",
"S.",
""
],
[
"D'Avanzo",
"P.",
""
],
[
"D'Elia",
"V.",
""
],
[
"Fugazza",
"D.",
""
],
[
"Piranomonte",
"S.",
""
],
[
"Ballo",
"L.",
""
],
[
"Campana",
"S.",
""
],
[
"Stella",
"L.",
""
],
[
"Tagliaferri",
"G.",
""
],
[
"Antonelli",
"L. A.",
""
],
[
"Chincarini",
"G.",
""
],
[
"Della Valle",
"M.",
""
],
[
"Goldoni",
"P.",
""
],
[
"Guidorzi",
"C.",
""
],
[
"Israel",
"G. L.",
""
],
[
"Lazzati",
"D.",
""
],
[
"Melandri",
"A.",
""
],
[
"Pellizza",
"L. J.",
""
],
[
"Romano",
"P.",
""
],
[
"Stratta",
"G.",
""
],
[
"Vergani",
"S. D.",
""
]
] |
0706.1274 | Fulai Guo | Fulai Guo, S. Peng OH (UCSB) | Feedback Heating by Cosmic Rays in Clusters of Galaxies | Revised version accepted for publication in MNRAS. Significantly
expanded discussion and new simulations exploring parameter space/model
robustness; conclusions unchanged | null | 10.1111/j.1365-2966.2007.12692.x | null | astro-ph | null | Recent observations show that the cooling flows in the central regions of
galaxy clusters are highly suppressed. Observed AGN-induced cavities/bubbles
are a leading candidate for suppressing cooling, usually via some form of
mechanical heating. At the same time, observed X-ray cavities and synchrotron
emission point toward a significant non-thermal particle population. Previous
studies have focused on the dynamical effects of cosmic-ray pressure support,
but none have built successful models in which cosmic-ray heating is
significant. Here we investigate a new model of AGN heating, in which the
intracluster medium is efficiently heated by cosmic-rays, which are injected
into the ICM through diffusion or the shredding of the bubbles by
Rayleigh-Taylor or Kelvin-Helmholtz instabilities. We include thermal
conduction as well. Using numerical simulations, we show that the cooling
catastrophe is efficiently suppressed. The cluster quickly relaxes to a
quasi-equilibrium state with a highly reduced accretion rate and temperature
and density profiles which match observations. Unlike the conduction-only case,
no fine-tuning of the Spitzer conduction suppression factor f is needed. The
cosmic ray pressure, P_c/P_g <~ 0.1 and dP_c/dr <~ 0.1 \rho g, is well within
observational bounds. Cosmic ray heating is a very attractive alternative to
mechanical heating, and may become particularly compelling if GLAST detects the
gamma-ray signature of cosmic-rays in clusters.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 00:21:25 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Nov 2007 21:49:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Guo",
"Fulai",
"",
"UCSB"
],
[
"OH",
"S. Peng",
"",
"UCSB"
]
] |
0706.1275 | Nathaniel Butler | Nathaniel R. Butler, Daniel Kocevski, Joshua S. Bloom, and Jason L.
Curtis | A Complete Catalog of Swift GRB Spectra and Durations: Demise of a
Physical Origin for Pre-Swift High-Energy Correlations | 25 pages, 9 figures, 2 tables, Accepted to ApJ | null | 10.1086/522492 | null | astro-ph | null | We calculate durations and spectral paramaters for 218 Swift bursts detected
by the BAT instrument between and including GRBs 041220 and 070509, including
77 events with measured redshifts. Incorporating prior knowledge into the
spectral fits, we are able to measure the characteristic $\nu F_{\nu}$ spectral
peak energy $E_{\rm pk,obs}$ and the isotropic equivalent energy $E_{\rm iso}$
(1--$10^4$ keV) for all events. This complete and rather extensive catalog,
analyzed with a unified methodology, allows us to address the persistence and
origin of high-energy correlations suggested in pre-Swift observations. We find
that the $E_{\rm pk,obs}$-$E_{\rm iso}$ correlation is present in the Swift
sample; however, the best-fit powerlaw relation is inconsistent with the
best-fit pre-Swift relation at >5 sigma significance. Moreover, it has a factor
>~ 2 larger intrinsic scatter, after accounting for large errors on $E_{\rm
pk,obs}$. A large fraction of the Swift events are hard and subluminous
relative to (and inconsistent with) the pre-Swift relation, in agreement with
indications from BATSE GRBs without redshift. Moreover, we determine an
experimental threshold for the BAT detector and show how the $E_{\rm
pk,obs}$--$E_{\rm iso}$ correlation arises artificially due to partial
correlation with the threshold. We show that pre-Swift correlations found by
Amati et al.(2002), Yonetoku et al. (2004), Firmani et al.(2006) (and
independently by others) are likely unrelated to the physical properties of
GRBs and are likely useless for tests of cosmology. Also, an explanation of
these correlations in terms of a detector threshold provides a natural and
quantitative explanation for why short-duration GRBs and events at low redshift
tend to be outliers to the correlations.
| [
{
"version": "v1",
"created": "Sun, 10 Jun 2007 14:36:19 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jul 2007 18:49:45 GMT"
},
{
"version": "v3",
"created": "Sat, 11 Aug 2007 12:54:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Butler",
"Nathaniel R.",
""
],
[
"Kocevski",
"Daniel",
""
],
[
"Bloom",
"Joshua S.",
""
],
[
"Curtis",
"Jason L.",
""
]
] |
0706.1276 | Hirotaka Tamanoi | Hirotaka Tamanoi | Loop coproducts in string topology and triviality of higher genus TQFT
operations | Version 3: 15 pages, reorganizartion of the paper, part (2) added to
Theorem B, references added, improvement on exposition | null | null | null | math.AT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Cohen and Godin constructed positive boundary topological quantum field
theory (TQFT) structure on the homology of free loop spaces of oriented closed
smooth manifolds by associating a certain operations called string operations
to orientable surfaces with parametrized boundaries. We show that all TQFT
string operations associated to surfaces of genus at least one vanish
identically. This is a simple consequence of properties of the loop coproduct
which will be discussed in detail. One interesting property is that the loop
coproduct is nontrivial only on the degree $d$ homology group of the connected
component of $LM$ consisting of contractible loops, where $d=\dim M$, with
values in the degree 0 homology group of constant loops. Thus the loop
coproduct behaves in a dramatically simpler way than the loop product.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 23:44:01 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Sep 2008 07:16:02 GMT"
},
{
"version": "v3",
"created": "Sun, 16 Nov 2008 22:02:45 GMT"
}
] | 2008-11-17T00:00:00 | [
[
"Tamanoi",
"Hirotaka",
""
]
] |
0706.1277 | Hirotaka Tamanoi | Hirotaka Tamanoi | A Homotopy Theoretic Proof of the BV Identity in Loop Homology | 13 pages | null | null | null | math.AT | null | Chas and Sullivan proved the existence of a Batalin-Vilkovisky algebra
structure in the homology of free loop spaces on closed finite dimensional
smooth manifolds using chains and chain homotopies. This algebraic structure
involves an associative product called the loop product, a Lie bracket called
the loop bracket, and a square 0 operator called the BV operator. Cohen and
Jones gave a homotopy theoretic description of the loop product in terms of
spectra. In this paper, we give an explicit homotopy theoretic description of
the loop bracket and, using this description, we give a homological proof of
the BV identity connecting the loop product, the loop bracket, and the BV
operator. The proof is based on an observation that the loop bracket and the BV
derivation are given by the same cycle in the free loop space, except that they
differ by parametrization of loops.
| [
{
"version": "v1",
"created": "Fri, 8 Jun 2007 23:54:03 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Tamanoi",
"Hirotaka",
""
]
] |
0706.1278 | Krisztian Peters | Krisztian Peters | Higgs Searches at the Tevatron | 6 pages, 3 figures | null | null | null | hep-ex | null | Recent preliminary results obtained by the CDF and D0 Collaborations on
searches for the Higgs boson in proton anti-proton collisions at Sqrt(s)=1.96
TeV at the Fermilab Tevatron collider are discussed. The data, corresponding to
integrated luminosities of about 1 fb-1, show no excess of a signal above the
expected background in any of the decay channels examined. Instead, upper
limits at 95% Confidence Level on the cross section are established. Further, a
combined Standard Model Tevatron cross section limit is presented.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 00:07:40 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Peters",
"Krisztian",
""
]
] |
0706.1279 | Famaey Benoit | B. Famaey, G.W. Angus, G. Gentile, H.Y. Shan, H.S. Zhao | The wedding of modified dynamics and non-exotic dark matter in galaxy
clusters | to appear in World Scientific, proceedings of DARK 2007 | null | 10.1142/9789812814357_0039 | null | astro-ph | null | We summarize the status of Modified Newtonian Dynamics (MOND) in galaxy
clusters. The observed acceleration is typically larger than the acceleration
threshold of MOND in the central regions, implying that some dark matter is
necessary to explain the mass discrepancy there. A plausible resolution of this
issue is that the unseen mass in MOND is in the form of ordinary neutrinos with
masses just below the experimentally detectable limit. In particular, we show
that the lensing mass reconstructions of the clusters 1E0657-56 (the bullet
cluster) and Cl0024+17 (the ring) do not pose a new challenge to this scenario.
However, the mass discrepancy for cool X-ray emitting groups, in which
neutrinos cannot cluster, pose a more serious problem, meaning that dark
baryons could present a more satisfactory solution to the problem of unseen
mass in MOND clusters.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 10:03:15 GMT"
},
{
"version": "v2",
"created": "Mon, 26 Nov 2007 14:51:55 GMT"
}
] | 2017-08-23T00:00:00 | [
[
"Famaey",
"B.",
""
],
[
"Angus",
"G. W.",
""
],
[
"Gentile",
"G.",
""
],
[
"Shan",
"H. Y.",
""
],
[
"Zhao",
"H. S.",
""
]
] |
0706.1280 | Yi-Fang Chang | Yi-Fang Chang | The Extensive Special Relativity and Comment on Local Lorentz
Transformation in Varying Speed of Light Theory | 6 papers | null | null | null | physics.gen-ph | null | It is proved that local Lorentz transformations for different systems cannot
derive varying speed of light. Based on the special relativity principle, an
invariant speed is necessarily obtained. Therefore, the exact basic principles
of the special relativity should be redefined as: I. The special relativity
principle, which derives necessarily an invariant speed. II. Suppose that the
invariant speed in the theory is the speed of light in the vacuum c. If the
second principle does not hold, for example, the superluminal motions exist,
the theory will be still the extensive special relativity, in which the
formulations are the same, only c is replaced by the invariant speed. If the
invariant speed are various invariant velocities, the diversity of space-time
will correspond to many worlds. Varying speed of light theory is probably
connected only with the general relativity.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 00:51:08 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Chang",
"Yi-Fang",
""
]
] |
0706.1281 | Nausheen Shah | Anibal D. Medina, Nausheen R. Shah and Carlos E. M. Wagner | Gauge-Higgs Unification and Radiative Electroweak Symmetry Breaking in
Warped Extra Dimensions | 31 pages, 9 figures. Corrected typo in boundary condition for gauge
bosons and top mass equation. To appear in PRD | Phys.Rev.D76:095010,2007 | 10.1103/PhysRevD.76.095010 | null | hep-ph hep-ex hep-th | null | We compute the Coleman Weinberg effective potential for the Higgs field in RS
Gauge-Higgs unification scenarios based on a bulk SO(5) x U(1)_X gauge
symmetry, with gauge and fermion fields propagating in the bulk and a custodial
symmetry protecting the generation of large corrections to the T parameter and
the coupling of the Z to the bottom quark. We demonstrate that electroweak
symmetry breaking may be realized, with proper generation of the top and bottom
quark masses for the same region of bulk mass parameters that lead to good
agreement with precision electroweak data in the presence of a light Higgs. We
compute the Higgs mass and demonstrate that for the range of parameters for
which the Higgs boson has Standard Model-like properties, the Higgs mass is
naturally in a range that varies between values close to the LEP experimental
limit and about 160 GeV. This mass range may be probed at the Tevatron and at
the LHC. We analyze the KK spectrum and briefly discuss the phenomenology of
the light resonances arising in our model.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 02:11:56 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Sep 2007 14:13:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Medina",
"Anibal D.",
""
],
[
"Shah",
"Nausheen R.",
""
],
[
"Wagner",
"Carlos E. M.",
""
]
] |
0706.1282 | Dao Tien Khoa | Dao T. Khoa, Hoang Sy Than, and Do Cong Cuong | Folding model study of the isobaric analog excitation: isovector density
dependence, Lane potential and nuclear symmetry energy | Accepted for publication in Phys. Rev. C | Phys.Rev.C76:014603,2007 | 10.1103/PhysRevC.76.014603 | null | nucl-th nucl-ex | null | A consistent folding model analysis of the ($\Delta S=0, \Delta T=1$) charge
exchange \pn reaction measured with $^{48}$Ca, $^{90}$Zr, $^{120}$Sn and
$^{208}$Pb targets at the proton energies of 35 and 45 MeV is done within a
two-channel coupling formalism. The nuclear ground state densities given by the
Hartree-Fock-Bogoljubov formalism and the density dependent CDM3Y6 interaction
were used as inputs for the folding calculation of the nucleon optical
potential and \pn form factor. To have an accurate isospin dependence of the
interaction, a complex isovector density dependence of the CDM3Y6 interaction
has been carefully calibrated against the microscopic Brueckner-Hatree-Fock
calculation by Jeukenne, Lejeune and Mahaux before being used as folding input.
Since the isovector coupling was used to explicitly link the isovector part of
the nucleon optical potential to the cross section of \pn reaction exciting the
0$^+$ isobaric analog states in $^{48}$Sc, $^{90}$Nb, $^{120}$Sb and
$^{208}$Bi, the newly parameterized isovector density dependence could be well
tested in the folding model analysis of the \pn reaction. The isospin- and
density dependent CDM3Y6 interaction was further used in the Hartree-Fock
calculation of asymmetric nuclear matter, and a realistic estimation of the
nuclear symmetry energy has been made.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 01:37:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Khoa",
"Dao T.",
""
],
[
"Than",
"Hoang Sy",
""
],
[
"Cuong",
"Do Cong",
""
]
] |
0706.1283 | Ravi Kumar Kopparapu | Ravi Kumar Kopparapu, Chad R. Hanna, Vicky Kalogera, Richard
O'Shaughnessy, Gabriela Gonzalez, Patrick R. Brady, Stephen Fairhurst | Host Galaxies Catalog Used in LIGO Searches for Compact Binary
Coalescence Events | 29 pages, 7 figures, Accepted to Astrophysical Journal. To appear in
March 20 2008 Astrophysical Journal | null | 10.1086/527348 | null | astro-ph | null | An up-to-date catalog of nearby galaxies considered as hosts of binary
compact objects is provided with complete information about sky position,
distance, extinction-corrected blue luminosity and error estimates. With our
current understanding of binary evolution, rates of formation and coalescence
for binary compact objects scale with massive-star formation and hence the
(extinction-corrected) blue luminosity of host galaxies. Coalescence events in
binary compact objects are among the most promising gravitational-wave sources
for ground-based gravitational-wave detectors such as LIGO. Our catalog and
associated error estimates are important for the interpretation of analyses,
carried out for LIGO, to constrain the rates of compact binary coalescence,
given an astrophysical population model for the sources considered. We discuss
how the notion of effective distance, created to account for the antenna
pattern of a gravitational-wave detector, must be used in conjunction with our
catalog. We note that the catalog provided can be used on other astronomical
analysis of populations that scale with galaxy blue luminosity.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 02:31:04 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 15:33:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kopparapu",
"Ravi Kumar",
""
],
[
"Hanna",
"Chad R.",
""
],
[
"Kalogera",
"Vicky",
""
],
[
"O'Shaughnessy",
"Richard",
""
],
[
"Gonzalez",
"Gabriela",
""
],
[
"Brady",
"Patrick R.",
""
],
[
"Fairhurst",
"Stephen",
""
]
] |
0706.1284 | Yi Liao | Yi Liao (Nankai U.), Ji-Yuan Liu (Nankai U.) | Long-range Electron Spin-spin Interactions from Unparticle Exchange | v1: 10 pages, no figure, 1 table; v2: Proofread version for PRL. Main
changes: (1) Shortened considerably to meet the length limit by cutting some
calculational details. (2) Introduction paragraphs hopefully improved. (3)
Minor rewording in the text and title. There are no changes to numerical
results and conclusions | Phys.Rev.Lett.99:191804,2007 | 10.1103/PhysRevLett.99.191804 | null | hep-ph hep-ex | null | Unparticles as suggested by Georgi are identities that are not constrained by
dispersion relations but are governed by their scaling dimension, d. Their
coupling to particles can result in macroscopic interactions between matter,
that are generally an inverse nonintegral power of distance. This is totally
different from known macroscopic forces. We use the precisely measured
long-ranged spin-spin interaction of electrons to constrain unparticle
couplings to the electron. For 1<d<1.5 the axial vector unparticle coupling is
excluded; and for 1<d<1.3 the pseudoscalar and vector couplings are also ruled
out. These bounds and the ones for other ranges of d exceed or are
complementary to those obtained previously from exotic positronium decays.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 03:32:06 GMT"
},
{
"version": "v2",
"created": "Sat, 3 Nov 2007 07:53:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liao",
"Yi",
"",
"Nankai U."
],
[
"Liu",
"Ji-Yuan",
"",
"Nankai U."
]
] |
0706.1285 | Kathy Cooksey | Kathy L. Cooksey (1), Jason X. Prochaska (1 and 2), Hsiao-Wen Chen
(3), John S. Mulchaey (4), Benjamin J. Weiner (5) ((1) UC Santa Cruz, (2)
UCO/Lick Obs., (3) U Chicago, (4) Obs. of Carnegie Inst. of Washington, (5)
Steward Obs., U of Arizona) | Characterizing the Low-Redshift Intergalactic Medium towards PKS1302-102 | 21 pages in emulatepj form, 24 figures, 10 tables, accepted to ApJ | null | 10.1086/528704 | null | astro-ph | null | We present a detailed analysis of the intergalactic metal-line absorption
systems in the archival HST/STIS and FUSE ultraviolet spectra of the
low-redshift quasar PKS1302-102 (z_QSO = 0.2784). We supplement the archive
data with CLOUDY ionization models and a survey of galaxies in the quasar
field. There are 15 strong Lya absorbers with column densities logN_HI > 14. Of
these, six are associated with at least CIII 977 absorption (logN(C^++) > 13);
this implies a redshift density dN_CIII/dz = 36+13/-9 (68% confidence limits)
for the five detections with rest equivalent width W_r > 50 mA. Two systems
show OVI 1031,1037 absorption in addition to CIII (logN(O^+5) > 14). One is a
partial Lyman limit system (logN_HI = 17) with associated CIII, OVI, and SiIII
1206 absorption. There are three tentative OVI systems that do not have CIII
detected. For one OVI doublet with both lines detected at 3 sigma with W_r > 50
mA, dN_OVI/dz = 7+9/-4. We also search for OVI doublets without Lya absorption
but identify none. From CLOUDY modeling, these metal-line systems have
metallicities spanning the range -4 < [M/H] < -0.3. The two OVI systems with
associated CIII absorption cannot be single-phase, collisionally-ionized media
based on the relative abundances of the metals and kinematic arguments. From
the galaxy survey, we discover that the absorption systems are in a diverse set
of galactic environments. Each metal-line system has at least one galaxy within
500 km/s and 600 h^-1 kpc with L > 0.1 L_*.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 05:57:32 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Dec 2007 22:20:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cooksey",
"Kathy L.",
"",
"1 and 2"
],
[
"Prochaska",
"Jason X.",
"",
"1 and 2"
],
[
"Chen",
"Hsiao-Wen",
""
],
[
"Mulchaey",
"John S.",
""
],
[
"Weiner",
"Benjamin J.",
""
]
] |
0706.1286 | Michael Shulman | Michael A. Shulman | Framed bicategories and monoidal fibrations | 80 pages. Main definition simplified. Final version, to appear in TAC | Theory Appl. Categ. 20 (2008), No. 18, 650--738 | null | null | math.CT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In some bicategories, the 1-cells are `morphisms' between the 0-cells, such
as functors between categories, but in others they are `objects' over the
0-cells, such as bimodules, spans, distributors, or parametrized spectra. Many
bicategorical notions do not work well in these cases, because the `morphisms
between 0-cells', such as ring homomorphisms, are missing. We can include them
by using a pseudo double category, but usually these morphisms also induce base
change functors acting on the 1-cells. We avoid complicated coherence problems
by describing base change `nonalgebraically', using categorical fibrations. The
resulting `framed bicategories' assemble into 2-categories, with attendant
notions of equivalence, adjunction, and so on which are more appropriate for
our examples than are the usual bicategorical ones.
We then describe two ways to construct framed bicategories. One is an
analogue of rings and bimodules which starts from one framed bicategory and
builds another. The other starts from a `monoidal fibration', meaning a
parametrized family of monoidal categories, and produces an analogue of the
framed bicategory of spans. Combining the two, we obtain a construction which
includes both enriched and internal categories as special cases.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 04:19:34 GMT"
},
{
"version": "v2",
"created": "Fri, 9 Jan 2009 19:47:32 GMT"
}
] | 2010-03-15T00:00:00 | [
[
"Shulman",
"Michael A.",
""
]
] |
0706.1287 | Robert Kohn | Helen Armstrong, Christopher K. Carter, Kevin F. Wong and Robert Kohn | Bayesian Covariance Matrix Estimation using a Mixture of Decomposable
Graphical Models | 28 pages and 11 figures | null | null | null | stat.ME | null | A Bayesian approach is used to estimate the covariance matrix of Gaussian
data. Ideas from Gaussian graphical models and model selection are used to
construct a prior for the covariance matrix that is a mixture over all
decomposable graphs. For this prior the probability of each graph size is
specified by the user and graphs of equal size are assigned equal probability.
Most previous approaches assume that all graphs are equally probable. We show
empirically that the prior that assigns equal probability over graph sizes
outperforms the prior that assigns equal probability over all graphs, both in
identifying the correct decomposable graph and in more efficiently estimating
the covariance matrix.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 04:55:02 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Armstrong",
"Helen",
""
],
[
"Carter",
"Christopher K.",
""
],
[
"Wong",
"Kevin F.",
""
],
[
"Kohn",
"Robert",
""
]
] |
0706.1288 | Eilon Poem | E. Poem, J. Shemesh, I. Marderfeld, D. Galushko, N. Akopian, D.
Gershoni, B. D. Gerardot, A. Badolato, P. M. Petroff | Polarization sensitive spectroscopy of charged Quantum Dots | 11 pages, 9 figures. Revised version | null | 10.1103/PhysRevB.76.235304 | null | cond-mat.mes-hall | null | We present an experimental and theoretical study of the polarized
photoluminescence spectrum of single semiconductor quantum dots in various
charge states. We compare our high resolution polarization sensitive spectral
measurements with a new many-carrier theoretical model, which was developed for
this purpose. The model considers both the isotropic and anisotropic exchange
interactions between all participating electron-hole pairs. With this addition,
we calculate both the energies and polarizations of all optical transitions
between collective, quantum dot confined charge carrier states. We succeed in
identifying most of the measured spectral lines. In particular, the lines
resulting from singly-, doubly- and triply- negatively charged excitons and
biexcitons. We demonstrate that lines emanating from evenly charged states are
linearly polarized. Their polarization direction does not necessarily coincide
with the traditional crystallographic direction. It depends on the shells of
the single carriers, which participate in the recombination process.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 08:25:54 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Oct 2007 21:21:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Poem",
"E.",
""
],
[
"Shemesh",
"J.",
""
],
[
"Marderfeld",
"I.",
""
],
[
"Galushko",
"D.",
""
],
[
"Akopian",
"N.",
""
],
[
"Gershoni",
"D.",
""
],
[
"Gerardot",
"B. D.",
""
],
[
"Badolato",
"A.",
""
],
[
"Petroff",
"P. M.",
""
]
] |
0706.1289 | Roberto Zucchini | Roberto Zucchini | The Hitchin Model, Poisson-quasi-Nijenhuis Geometry and Symmetry
Reduction | 38 pages, no figures, LaTex. One paragraph in sect. 6 and 3
references added | JHEP 0710:075,2007 | 10.1088/1126-6708/2007/10/075 | DFUB 06/07 | hep-th math-ph math.DG math.MP | null | We revisit our earlier work on the AKSZ formulation of topological sigma
model on generalized complex manifolds, or Hitchin model. We show that the
target space geometry geometry implied by the BV master equations is
Poisson--quasi--Nijenhuis geometry recently introduced and studied by Sti\'enon
and Xu (in the untwisted case). Poisson--quasi--Nijenhuis geometry is more
general than generalized complex geometry and comprises it as a particular
case. Next, we show how gauging and reduction can be implemented in the Hitchin
model. We find that the geometry resulting form the BV master equation is
closely related to but more general than that recently described by Lin and
Tolman, suggesting a natural framework for the study of reduction of
Poisson--quasi--Nijenhuis manifolds.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 06:42:13 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 14:54:42 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Zucchini",
"Roberto",
""
]
] |
0706.1290 | Sylviane Schwer | Sylviane R. Schwer (LIPN) | Temporal Reasoning without Transitive Tables | rapport interne | null | null | null | cs.AI | null | Representing and reasoning about qualitative temporal information is an
essential part of many artificial intelligence tasks. Lots of models have been
proposed in the litterature for representing such temporal information. All
derive from a point-based or an interval-based framework. One fundamental
reasoning task that arises in applications of these frameworks is given by the
following scheme: given possibly indefinite and incomplete knowledge of the
binary relationships between some temporal objects, find the consistent
scenarii between all these objects. All these models require transitive tables
-- or similarly inference rules-- for solving such tasks. We have defined an
alternative model, S-languages - to represent qualitative temporal information,
based on the only two relations of \emph{precedence} and \emph{simultaneity}.
In this paper, we show how this model enables to avoid transitive tables or
inference rules to handle this kind of problem.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 06:57:05 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Schwer",
"Sylviane R.",
"",
"LIPN"
]
] |
0706.1291 | Maria J. Esteban | Maria J. Esteban (CEREMADE), Michael Loss | Self-adjointness of Dirac operators via Hardy-Dirac inequalities | PACS 03.65.P, 03.30 | Journal of Mathematical Physics 48, 11 (2007) 112107 | 10.1063/1.2811950 | null | math.AP math-ph math.MP | null | Distinguished selfadjoint extensions of Dirac operators are constructed for a
class of potentials including Coulombic ones up to the critical case,
$-|x|^{-1}$. The method uses Hardy-Dirac inequalities and quadratic form
techniques.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 06:58:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Esteban",
"Maria J.",
"",
"CEREMADE"
],
[
"Loss",
"Michael",
""
]
] |
0706.1292 | Sungeun Kim | S. Kim, E. Rosolowsky, Y. Lee, Y. Kim, Y.C. Jung, M.A. Dopita, B.G.
Elmegreen, K.C. Freeman, R.J. Sault, M.J. Kesteven, D. McConnell, and Y.-H.
Chu | A Catalog of HI Clouds in the Large Magellanic Cloud | 24 pages, 15 figures, ApJS, in press | null | 10.1086/518126 | null | astro-ph | null | A 21 cm neutral hydrogen interferometric survey of the Large Magellanic Cloud
(LMC) combined with the Parkes multi-beam HI single-dish survey clearly shows
that the HI gas is distributed in the form of clumps or clouds. The HI clouds
and clumps have been identified using a thresholding method with three separate
brightness temperature thresholds ($T_b$). Each catalog of HI cloud candidates
shows a power law relationship between the sizes and the velocity dispersions
of the clouds roughly following the Larson Law scaling $\sigma_v \propto
R^{0.5}$, with steeper indices associated with dynamically hot regions. The
clouds in each catalog have roughly constant virial parameters as a function
mass suggesting that that the clouds are all in roughly the same dynamical
state, but the values of the virial parameter are significantly larger than
unity showing that turbulent motions dominate gravity in these clouds. The mass
distribution of the clouds is a power law with differential indices between
-1.6 and -2.0 for the three catalogs. In contrast, the distribution of mean
surface densities is a log-normal distribution.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 11:00:58 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 04:22:47 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Kim",
"S.",
""
],
[
"Rosolowsky",
"E.",
""
],
[
"Lee",
"Y.",
""
],
[
"Kim",
"Y.",
""
],
[
"Jung",
"Y. C.",
""
],
[
"Dopita",
"M. A.",
""
],
[
"Elmegreen",
"B. G.",
""
],
[
"Freeman",
"K. C.",
""
],
[
"Sault",
"R. J.",
""
],
[
"Kesteven",
"M. J.",
""
],
[
"McConnell",
"D.",
""
],
[
"Chu",
"Y. -H.",
""
]
] |
0706.1293 | Natalia Kudryavtseva | N.P. Bondar, I.L. Kovalenko, D.F. Avgustinovich, N.N. Kudryavtseva | Influence of experimental context on the development of anhedonia in
male mice imposed to chronic social stress | 9 pages, 3 figures, 1 table | null | null | null | q-bio.OT q-bio.QM | null | Anhedonia is one of the key symptoms of depression in humans. Consumption of
1% sucrose solution supplemented with 0.2% vanillin was studied in two
experimental contexts in male mice living under chronic social stress induced
by daily experience of defeats in agonistic interactions and leading to
development of depression. In the first experiment, vanillin sucrose solution
was made available as an option of water during 10 days to mice living in group
home cages. Then the mice were subjected to social defeat stress and during
stress exposure they were provided with both vanillin sucrose solution and
water using a free two bottles choice paradigm. In the other experiment,
vanillin sucrose solution were first offered to mice after 8 days of exposure
to social defeat stress. Males familiar with vanillin sucrose solution showed
vanillin sucrose preference while experiencing defeat stress: consumption of
vanillin sucrose solution was about 70% of total liquid consumption. However,
the consumption of vanillin sucrose solution per gram of body weight in mice
imposed to social stress during 20 days was significantly lower than in control
males. In the second experiment, males after 8 days of social defeat stress
were found to consume significantly less vanillin sucrose solution as compared
with control males. On average during two weeks of measurements, vanillin
sucrose solution intake was less than 20% of total liquid consumption in males
with symptoms of depression and anxiety. Consumption per gram of body weight
also appeared to be significantly lower than in control group. Influence of the
experimental context on the development of anhedonia, which was measured by the
reduction in sucrose solution intake by chronically stressed male mice, has
been discussed.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 08:12:55 GMT"
},
{
"version": "v2",
"created": "Sat, 16 Jun 2007 08:20:15 GMT"
},
{
"version": "v3",
"created": "Sat, 10 May 2008 08:45:09 GMT"
}
] | 2008-05-10T00:00:00 | [
[
"Bondar",
"N. P.",
""
],
[
"Kovalenko",
"I. L.",
""
],
[
"Avgustinovich",
"D. F.",
""
],
[
"Kudryavtseva",
"N. N.",
""
]
] |
0706.1294 | Gamal Nashed G.L. | Gamal Gergess Lamee Nashed | Comments Brane-World Black Holes and Energy-Momentum Vector | 2 Pages Latex, This is a comments on the paper "arXiv:gr-qc/0611014" | null | null | null | gr-qc | null | We show that the energy distribution of the brane-world black holes given by
Salti et al. in the context of teleparallel theory is not right. We give the
correct formula of energy of those black hole.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 08:49:47 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Nashed",
"Gamal Gergess Lamee",
""
]
] |
0706.1295 | Arun Palakkandy | Charu Saxena, Rini Kaur, P.Arun | Reaction Time of a Group of Physics Students | 10 pages, 4 figures | null | 10.1088/0031-9120/43/3/010 | null | physics.ed-ph | null | The reaction time of a group of students majoring in Physics is reported
here. Strong co-relation between fatigue, reaction time and performance have
been seen and may be useful for academicians and administrators responsible of
working out time-tables, course structures, students counsellings etc.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 09:03:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Saxena",
"Charu",
""
],
[
"Kaur",
"Rini",
""
],
[
"Arun",
"P.",
""
]
] |
0706.1296 | Nirav Mehta | Nirav P. Mehta, Seth T. Rittenhouse, Jose P. D'Incao, Chris H. Greene | Hyperspherical approach to the four-body problem | 10 pages, 3 figures. To be published in: Atomic Structure and
Collision Processes Publisher: Narosa | null | null | null | cond-mat.other | null | The four-particle system is the simplest few-body system containing the
fundamental physics involved in ultracold fermionic gases. We have made recent
efforts to solve the quantum four-body problem in the adiabatic hyperspherical
representation. Our approach yields a set of coupled potential curves that can
in turn be solved for all elastic and inelastic processes. These rates may play
an important role in the lifetime of molecules in ultracold fermi gases. We
believe this will lead to a deeper understanding of ultracold fermi systems and
the physics of the BCS-BEC crossover.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 18:48:08 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Mehta",
"Nirav P.",
""
],
[
"Rittenhouse",
"Seth T.",
""
],
[
"D'Incao",
"Jose P.",
""
],
[
"Greene",
"Chris H.",
""
]
] |
0706.1297 | R. Ramakumar | R. Ramakumar and A. N. Das | Lattice bosons in quartic confinement | revised version, 11 pages including figures, accepted in EPJD | Eur. Phys. J. D 47, 203 (2008) | 10.1140/epjd/e2008-00031-5 | null | cond-mat.other cond-mat.stat-mech | null | We present a theoretical study of bose condensation of non-interacting bosons
in finite lattices in quartic potentials in one, two, and three dimensions. We
investigate dimensionality effects and quartic potential effects on single
boson density of energy states, condensation temperature, condensate fraction,
and specific heat. The results obtained are compared with corresponding results
for lattice bosons in harmonic traps.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 09:26:24 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Jan 2008 09:38:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ramakumar",
"R.",
""
],
[
"Das",
"A. N.",
""
]
] |
0706.1298 | Suresh Tiwari dr | S. C. Tiwari | On the harmonic map equation | 2 pages, no figures | null | null | null | gr-qc | null | A generalized harmonic map equation is presented based on the proposed action
functional in the Weyl space (PLA, 135, 315, 1989).
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 10:08:08 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Tiwari",
"S. C.",
""
]
] |
0706.1299 | Cappellaro Enrico | Enrico Cappellaro, Maria Teresa Botticella, Laura Greggio | The evolution of the cosmic SN rate | 8 pages, to appear in the AIP conference proceedings of "Supernova
1987A: 20 Years after Supernovae and Gamma-Ray Bursters", Feb 19-23, 2007,
Aspen, CO | AIP Conf.Proc.937:198-205,2007 | 10.1063/1.2803563 | null | astro-ph | null | We briefly review the contribution of SN rate measurements to the debate on
SN progenitor scenarios. We find that core collapse rates confirms the rapid
evolution of the star formation rate with redshift. After accounting for the
dispersion of SN Ia measurements and uncertainty of the star formation history,
the standard scenarios for SN Ia progenitors appear consistent with all
observational constraints.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 13:22:51 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Cappellaro",
"Enrico",
""
],
[
"Botticella",
"Maria Teresa",
""
],
[
"Greggio",
"Laura",
""
]
] |
0706.1300 | Andreas Boukas | Luigi Accardi and Andreas Boukas | The Quantum Black-Scholes Equation | Has appeared in GJPAM, vol. 2, no. 2, pp. 155-170 (2006) | GJPAM, vol. 2, no. 2, pp. 155-170 (2006) | null | null | q-fin.PR math-ph math.MP | null | Motivated by the work of Segal and Segal on the Black-Scholes pricing formula
in the quantum context, we study a quantum extension of the Black-Scholes
equation within the context of Hudson-Parthasarathy quantum stochastic
calculus. Our model includes stock markets described by quantum Brownian motion
and Poisson process.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 11:18:16 GMT"
}
] | 2020-06-23T00:00:00 | [
[
"Accardi",
"Luigi",
""
],
[
"Boukas",
"Andreas",
""
]
] |
0706.1301 | Carel Faber | Paolo Aluffi, Carel Faber | Limits of PGL(3)-translates of plane curves, I | 28 pages. Minor revision. Final version | J. Pure Appl. Algebra 214 (2010), no. 5, 526-547 | 10.1016/j.jpaa.2009.06.010 | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We classify all possible limits of families of translates of a fixed,
arbitrary complex plane curve. We do this by giving a set-theoretic description
of the projective normal cone (PNC) of the base scheme of a natural rational
map, determined by the curve, from the $P^8$ of 3x3 matrices to the $P^N$ of
plane curves of degree $d$. In a sequel to this paper we determine the
multiplicities of the components of the PNC. The knowledge of the PNC as a
cycle is essential in our computation of the degree of the PGL(3)-orbit closure
of an arbitrary plane curve, performed in our earlier paper "Linear orbits of
arbitrary plane curves".
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 11:21:06 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 13:07:37 GMT"
},
{
"version": "v3",
"created": "Thu, 5 Feb 2009 00:38:27 GMT"
},
{
"version": "v4",
"created": "Sat, 6 Jun 2009 20:36:54 GMT"
}
] | 2012-04-11T00:00:00 | [
[
"Aluffi",
"Paolo",
""
],
[
"Faber",
"Carel",
""
]
] |
0706.1302 | Mar\'ia Dolores Caballero-Garc\'ia | M.D.Caballero-Garcia (1), J.M.Miller (2), E.Kuulkers (3), M.Diaz Trigo
(3), J.Homan (4), W.H.G. Lewin (4), P.Kretschmar (3), A.Domingo (1),
J.M.Mas-Hesse (5), R.Wijnands (6), A.C.Fabian (7), R.P.Fender (8,6), M.van
der Klis (6) ((1)LAEFF-INTA, (2)U. of Michigan, (3)ESA/ESAC, (4)MIT,
(5)CAB-CSIC-INTA, (6)Anton Pannekoek, (7)U. of Cambridge, (8)U. of
Southampton) | The high energy emission of GRO J1655-40 as revealed with INTEGRAL
spectroscopy of the 2005 outburst | 14 figures. Accepted for publication in ApJ. Revised text for typos
and deleted last line of third paragraph in page 14 (last try) | null | 10.1086/520764 | null | astro-ph | null | We present broadband (3-500 keV) INTEGRAL X-ray spectra and X-ray/optical
light curves of the luminous black hole X-ray transient and relativistic jet
source GRO J1655-40. Our analysis covers four Target of Opportunity
observations of the outburst that started in February 2005. We find that the
high energy emission of GRO J1655-40 can be modelled well with an unbroken
power-law (with photon indices of 1.72+-0.03,2.21+-0.04 for the first and the
second observations, respectively). These correspond to hard and thermal
dominant states, respectively. In contrast to many other black hole spectra,
high energy complexity in the form of a break or cut-off is not required for
the hard state, contrary to previous expectations for this state. We show for
the first time that Comptonization by non-thermal electrons is the dominant
process for the high energy emission in the hard state. We discuss our results
in terms of models for broad-band emission and accretion flows in stellar-mass
black holes.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 11:34:49 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Sep 2007 10:10:28 GMT"
},
{
"version": "v3",
"created": "Tue, 11 Sep 2007 09:49:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Caballero-Garcia",
"M. D.",
""
],
[
"Miller",
"J. M.",
""
],
[
"Kuulkers",
"E.",
""
],
[
"Trigo",
"M. Diaz",
""
],
[
"Homan",
"J.",
""
],
[
"Lewin",
"W. H. G.",
""
],
[
"Kretschmar",
"P.",
""
],
[
"Domingo",
"A.",
""
],
[
"Mas-Hesse",
"J. M.",
""
],
[
"Wijnands",
"R.",
""
],
[
"Fabian",
"A. C.",
""
],
[
"Fender",
"R. P.",
""
],
[
"van der Klis",
"M.",
""
]
] |
0706.1303 | Peter Kuchment | M. Agranovsky, P. Kuchment, L. Kunyansky | On reconstruction formulas and algorithms for the thermoacoustic
tomography | null | Ch. 8 in L. H. Wang (Editor) "Photoacoustic imaging and
spectroscopy," CRC Press 2009, pp. 89-101. | null | null | math.AP math.NA | null | The paper surveys recent progress in establishing uniqueness and developing
inversion formulas and algorithms for the thermoacoustic tomography. In
mathematical terms, one deals with a rather special inverse problem for the
wave equation. In the case of constant sound speed, it can also be interpreted
as a problem concerning the spherical mean transform.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 11:45:34 GMT"
},
{
"version": "v2",
"created": "Sun, 21 Oct 2007 18:11:54 GMT"
}
] | 2009-02-02T00:00:00 | [
[
"Agranovsky",
"M.",
""
],
[
"Kuchment",
"P.",
""
],
[
"Kunyansky",
"L.",
""
]
] |
0706.1304 | Carel Faber | Paolo Aluffi, Carel Faber | Limits of PGL(3)-translates of plane curves, II | 22 pages. Minor revision. Final version | J. Pure Appl. Algebra 214 (2010), no. 5, 548-564 | 10.1016/j.jpaa.2009.06.012 | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Every complex plane curve C determines a subscheme S of the $P^8$ of 3x3
matrices, whose projective normal cone (PNC) captures subtle invariants of C.
In "Limits of PGL(3)-translates of plane curves, I" we obtain a set-theoretic
description of the PNC and thereby we determine all possible limits of families
of plane curves whose general element is isomorphic to C. The main result of
this article is the determination of the PNC as a cycle; this is an essential
ingredient in our computation in "Linear orbits of arbitrary plane curves" of
the degree of the PGL(3)-orbit closure of an arbitrary plane curve, an
invariant of natural enumerative significance.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 11:57:45 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 13:28:56 GMT"
},
{
"version": "v3",
"created": "Thu, 5 Feb 2009 00:46:46 GMT"
},
{
"version": "v4",
"created": "Sat, 6 Jun 2009 20:49:39 GMT"
}
] | 2012-04-11T00:00:00 | [
[
"Aluffi",
"Paolo",
""
],
[
"Faber",
"Carel",
""
]
] |
0706.1305 | Sascha Husa | Mark Hannam, Sascha Husa, Jose A. Gonzalez, Ulrich Sperhake, Bernd
Bruegmann | Where post-Newtonian and numerical-relativity waveforms meet | 14 pages, 18 figures. Modifications resulting from bug fixes in LAL,
and extended analysis of numerical errors and phase agreement with PN, now
including the 3PN TaylorT3 approximant. No change to main conclusions | Phys.Rev.D77:044020,2008 | 10.1103/PhysRevD.77.044020 | null | gr-qc | null | We analyze numerical-relativity (NR) waveforms that cover nine orbits (18
gravitational-wave cycles) before merger of an equal-mass system with low
eccentricity, with numerical uncertainties of 0.25 radians in the phase and
less than 2% in the amplitude; such accuracy allows a direct comparison with
post-Newtonian (PN) waveforms. We focus on one of the PN approximants that has
been proposed for use in gravitational-wave data analysis, the restricted 3.5PN
``TaylorT1'' waveforms, and compare these with a section of the numerical
waveform from the second to the eighth orbit, which is about one and a half
orbits before merger. This corresponds to a gravitational-wave frequency range
of $M\omega = 0.0455$ to 0.1. Depending on the method of matching PN and NR
waveforms, the accumulated phase disagreement over this frequency range can be
within numerical uncertainty. Similar results are found in comparisons with an
alternative PN approximant, 3PN ``TaylorT3''. The amplitude disagreement, on
the other hand, is around 6%, but roughly constant for all 13 cycles that are
compared, suggesting that only 4.5 orbits need be simulated to match PN and NR
waves with the same accuracy as is possible with nine orbits. If, however, we
model the amplitude up to 2.5PN order, the amplitude disagreement is roughly
within numerical uncertainty up to about 11 cycles before merger.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 17:26:32 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2007 10:38:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hannam",
"Mark",
""
],
[
"Husa",
"Sascha",
""
],
[
"Gonzalez",
"Jose A.",
""
],
[
"Sperhake",
"Ulrich",
""
],
[
"Bruegmann",
"Bernd",
""
]
] |
0706.1306 | Alain Destexhe | Zuzanna Piwkowska, Martin Pospischil, Romain Brette, Julia Sliwa,
Michelle Rudolph-Lilith, Thierry Bal and Alain Destexhe | Characterizing synaptic conductance fluctuations in cortical neurons and
their influence on spike generation | 9 figures, Journal of Neuroscience Methods (in press, 2008) | Journal of Neuroscience Methods 169: 302-322, 2008. | null | null | q-bio.NC | null | Cortical neurons are subject to sustained and irregular synaptic activity
which causes important fluctuations of the membrane potential (Vm). We review
here different methods to characterize this activity and its impact on spike
generation. The simplified, fluctuating point-conductance model of synaptic
activity provides the starting point of a variety of methods for the analysis
of intracellular Vm recordings. In this model, the synaptic excitatory and
inhibitory conductances are described by Gaussian-distributed stochastic
variables, or colored conductance noise. The matching of experimentally
recorded Vm distributions to an invertible theoretical expression derived from
the model allows the extraction of parameters characterizing the synaptic
conductance distributions. This analysis can be complemented by the matching of
experimental Vm power spectral densities (PSDs) to a theoretical template, even
though the unexpected scaling properties of experimental PSDs limit the
precision of this latter approach. Building on this stochastic characterization
of synaptic activity, we also propose methods to qualitatively and
quantitatively evaluate spike-triggered averages of synaptic time-courses
preceding spikes. This analysis points to an essential role for synaptic
conductance variance in determining spike times. The presented methods are
evaluated using controlled conductance injection in cortical neurons in vitro
with the dynamic-clamp technique. We review their applications to the analysis
of in vivo intracellular recordings in cat association cortex, which suggest a
predominant role for inhibition in determining both sub- and supra-threshold
dynamics of cortical neurons embedded in active networks.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 12:32:51 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Nov 2007 20:52:01 GMT"
},
{
"version": "v3",
"created": "Thu, 15 Nov 2007 21:28:00 GMT"
}
] | 2009-04-29T00:00:00 | [
[
"Piwkowska",
"Zuzanna",
""
],
[
"Pospischil",
"Martin",
""
],
[
"Brette",
"Romain",
""
],
[
"Sliwa",
"Julia",
""
],
[
"Rudolph-Lilith",
"Michelle",
""
],
[
"Bal",
"Thierry",
""
],
[
"Destexhe",
"Alain",
""
]
] |
0706.1307 | Tiago Jos\'e Oliveira | T. J. Oliveira and F. D. A. Aarao Reis | Finite-size effects in roughness distribution scaling | 25 pages, including 9 figures and 1 table | Phys. Rev. E 76, 061601 (2007) | 10.1103/PhysRevE.76.061601 | null | cond-mat.stat-mech | null | We study numerically finite-size corrections in scaling relations for
roughness distributions of various interface growth models. The most common
relation, which considers the average roughness $<w_2>$ as scaling factor, is
not obeyed in the steady states of a group of ballistic-like models in 2+1
dimensions, even when very large system sizes are considered. On the other
hand, good collapse of the same data is obtained with a scaling relation that
involves the root mean square fluctuation of the roughness, which can be
explained by finite-size effects on second moments of the scaling functions. We
also obtain data collapse with an alternative scaling relation that accounts
for the effect of the intrinsic width, which is a constant correction term
previously proposed for the scaling of $<w_2>$. This illustrates how
finite-size corrections can be obtained from roughness distributions scaling.
However, we discard the usual interpretation that the intrinsic width is a
consequence of high surface steps by analyzing data of restricted
solid-on-solid models with various maximal height differences between
neighboring columns. We also observe that large finite-size corrections in the
roughness distributions are usually accompanied by huge corrections in height
distributions and average local slopes, as well as in estimates of scaling
exponents. The molecular-beam epitaxy model of Das Sarma and Tamborenea in 1+1
dimensions is a case example in which none of the proposed scaling relations
works properly, while the other measured quantities do not converge to the
expected asymptotic values. Thus, although roughness distributions are clearly
better than other quantities to determine the universality class of a growing
system, it is not the final solution for this task.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 14:12:33 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Feb 2008 11:33:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Oliveira",
"T. J.",
""
],
[
"Reis",
"F. D. A. Aarao",
""
]
] |
0706.1308 | E. V. Sampathkumaran | Niharika Mohapatra, Kartik K Iyer, Sudhindra Rayaprol and E.V.
Sampathkumaran | Geometrically frustrated magnetic behavior of Sr3NiRhO6 and Sr3NiPtO6 | A slightly different version from that of PRB version (that is to
appear in print). Phys, Rev, B, in press | null | 10.1103/PhysRevB.75.214422 | null | cond-mat.str-el cond-mat.mtrl-sci | null | The results of ac and dc magnetic susceptibility isothermal magnetization and
heat-capacity measurements as a function of temperature (T) are reported for
Sr3NiRhO6 and Sr3NiPtO6 containing magnetic chains arranged in a triangular
fashion in the basal plane and crystallizing in K4CdCl6-derived rhombohedral
structure. The results establish that both the compounds are magnetically
frustrated, however in different ways. In the case of the Rh compound, the
susceptibility data reveal that there are two magnetic transitions, one in the
range 10 -15 K and the other appearing as a smooth crossover near 45 K, with a
large frequency dependence of ac susceptibility in the range 10 to 40 K; in
addition, the features in C(T) are smeared out at these temperatures. The
magnetic properties are comparable to those of previously known few compounds
with partially disordered antiferromagnetic structure. On the other hand, for
Sr3NiPtO6, there is no evidence for long-range magnetic ordering down to 1.8 K
despite large value of paramagnetic Curie temperature.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 13:01:04 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 05:49:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mohapatra",
"Niharika",
""
],
[
"Iyer",
"Kartik K",
""
],
[
"Rayaprol",
"Sudhindra",
""
],
[
"Sampathkumaran",
"E. V.",
""
]
] |
0706.1309 | E. V. Sampathkumaran | Kartik K Iyer and E.V. Sampathkumaran | Superconducting behavior of the solid solution, Y2Pd(1-x)Pt(x)Ge3 | Physica C, in press | null | 10.1016/j.physc.2007.05.049 | null | cond-mat.supr-con cond-mat.str-el | null | The compound Y2PdGe3 was earlier reported by us to be one of the very few
ternary superconducting compounds (T_c= 3 K) belonging to the same structure as
that of MgB2. Here we report the results of electrical resistivity,
magnetization and heat capacity measurements at low temperatures on the solid
solution with a nominal starting composition, Y2Pd(1-x)Pt(x)Ge3, to understand
the influence of gradual replacement of Pd by Pt on T_c. The superconducting
properties of this solution is distinctly interesting in the sense that the Tc
varies monotonically with increasing x in sharp contrast to the non-monotonic
variation for other isostructural solid solutions reported recently.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 13:10:18 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Jun 2007 11:42:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Iyer",
"Kartik K",
""
],
[
"Sampathkumaran",
"E. V.",
""
]
] |
0706.1310 | Susanne Reffert | S. Reffert | The Geometer's Toolkit to String Compactifications | Lecture notes based on lectures given at the Workshop on String and
M-Theory Approaches to Particle Physics and Astronomy, Galileo Galilei
Institute for Theoretical Physics, Arcetri (Firenze). 52 pages | null | null | null | hep-th | null | These lecture notes are meant to serve as an introduction to some geometric
constructions and techniques (in particular the ones of toric geometry) often
employed by the physicist working on string theory compactifications. The
emphasis is wholly on the geometry side, not on the physics.
The treated topics include toroidal orbifolds, methods of toric geometry,
desinglularization of toroidal orbifolds and their orientifold quotients.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 13:20:57 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Reffert",
"S.",
""
]
] |
0706.1311 | Max Lieblich | Max Lieblich | Compactified moduli of projective bundles | 28 pages. Major reogranization and clarification. Hypothesis removed;
results as stated now apply to arbitrary stable bundles, with no constraint
on the rank | Algebra Number Theory 3 (2009), no. 6, 653-695 | null | null | math.AG math.RT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a method for compactifying stacks of $\PGL_n$-torsors (Azumaya
algebras) on algebraic spaces. In particular, when the ambient space is a
smooth projective surface we use our methods to show that various moduli spaces
are irreducible and carry natural virtual fundamental classes. We also prove a
version of the Skolem-Noether theorem for certain algebra objects in the
derived category, which allows us to give an explicit description of the
boundary points in our compactified moduli problem.
| [
{
"version": "v1",
"created": "Mon, 11 Jun 2007 19:21:33 GMT"
},
{
"version": "v2",
"created": "Mon, 20 Aug 2007 05:19:14 GMT"
},
{
"version": "v3",
"created": "Thu, 22 Nov 2007 16:08:48 GMT"
},
{
"version": "v4",
"created": "Mon, 25 May 2009 00:52:01 GMT"
}
] | 2018-06-18T00:00:00 | [
[
"Lieblich",
"Max",
""
]
] |
0706.1312 | Labib Haddad | Barben-Jean Coffi-Nketsia and Labib Haddad | Entrelacement d'alg\`ebres de Lie [Wreath products for Lie algebras] | A moderately detailed english summary of the paper can be found on
pages 9 to 15, in "Produit d'entrelacement et action triangulaire
d'alg\`ebres de Lie", arXiv:math.RT/0704.3840v1 | null | null | null | math.RT | null | Full details are given for the definition and construction of the wreath
product of two arbitrary Lie algebras, in the hope that it can lead to the
definition of a suitable Lie group to be the wreath product of two given Lie
groups. In the process, quite a few new notions are needed, and introduced.
Such are, for example : Formal series with variables in a vector space and
coefficients in some other vector space. Derivation of a formal series relative
to another formal series. The Lie algebra of a vector space. Formal actions of
Lie algebras over vector spaces. The basic formal action of a Lie algebra over
itself (as a formal version of the analytic aspect of the infinitesimal
operation law of a Lie groupuscule). More generally, the wreath product of two
Lie algebras is defined, relative to a formal action of the second onto an
arbitrary vector space. Main features are : A description of the triangular
actions of wreath products over product vector spaces, and a Kaloujnine-Krasner
type theorem : In essence, it says that all Lie extensions of a given Lie
algebra by another Lie algebra are, indeed, subalgebras of their wreath
product.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 14:38:18 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Coffi-Nketsia",
"Barben-Jean",
""
],
[
"Haddad",
"Labib",
""
]
] |
0706.1313 | Thierry Coulbois | Thierry Coulbois (LATP), Arnaud Hilion (LATP), Martin Lustig (LATP) | Non-unique ergodicity, observers' topology and the dual algebraic
lamination for $\R$-trees | to appear in the Illinois Journal of Math | Illinois Journal of Mathematics 51 (2007) 897-911 | null | null | math.GR | null | We continue in this article the study of laminations dual to very small
actions of a free group F on R-trees. We prove that this lamination determines
completely the combinatorial structure of the R-tree (the so-called observers'
topology). On the contrary the metric is not determined by the lamination, and
an R-tree may be equipped with different metrics which have the same observers'
topology.
| [
{
"version": "v1",
"created": "Sat, 9 Jun 2007 15:09:52 GMT"
}
] | 2010-02-05T00:00:00 | [
[
"Coulbois",
"Thierry",
"",
"LATP"
],
[
"Hilion",
"Arnaud",
"",
"LATP"
],
[
"Lustig",
"Martin",
"",
"LATP"
]
] |
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