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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.2114 | Yuji Tachikawa | Tohru Eguchi and Yuji Tachikawa | Rigid Limit in N=2 Supergravity and Weak-Gravity Conjecture | 17 pages, minor corrections | JHEP 0708:068,2007 | 10.1088/1126-6708/2007/08/068 | UT-07-21, YITP-07-35 | hep-th | null | We analyze the coupled N=2 supergravity and Yang-Mills system using
holomorphy, near the rigid limit where the former decouples from the latter. We
find that there appears generically a new mass scale around g M_{pl} where g is
the gauge coupling constant and M_{pl} is the Planck scale. This is in accord
with the weak-gravity conjecture proposed recently. We also study the scale
dependence of the gauge theory prepotential from its embedding into
supergravity.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:14:25 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jul 2007 15:31:08 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Eguchi",
"Tohru",
""
],
[
"Tachikawa",
"Yuji",
""
]
] |
0706.2115 | Debashish Chowdhury | Tripti Tripathi and Debashish Chowdhury | RNA polymerase motors on DNA track: effects of traffic congestion on RNA
synthesis | This paper is superseded by the more detailed version arXiv:0708.1067 | null | null | null | physics.bio-ph q-bio.GN | null | RNA polymerase (RNAP) is an enzyme that synthesizes a messenger RNA (mRNA)
strand which is complementary to a single-stranded DNA template. From the
perspective of physicists, an RNAP is a molecular motor that utilizes chemical
energy input to move along the track formed by a ssDNA. In some circumstances,
which are described in this paper, a large number of RNAPs move simultaneously
along the same track. We refer to such collective movements of the RNAPs as
RNAP traffic because of the similarities between the collective dynamics of the
RNAPs on ssDNA track and that of vehicles in highway traffic. In this paper we
develop a theoretical model for RNAP traffic by incorporating the steric
interactions between RNAPs as well as the mechano-chemical cycle of individual
RNAPs during the elongation of the mRNA. By a combination of analytical and
numerical techniques, we calculate the rates of mRNA synthesis and the average
density profile of the RNAPs on the ssDNA track. We also suggest novel
experiments for testing our theoretical predictions.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:14:47 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 17:25:58 GMT"
}
] | 2007-08-08T00:00:00 | [
[
"Tripathi",
"Tripti",
""
],
[
"Chowdhury",
"Debashish",
""
]
] |
0706.2116 | Frank Sottile | Luis Garcia-Puente and Frank Sottile | Linear precision for parametric patches | 21 pages, 5 figures | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give a precise mathematical formulation for the notions of a parametric
patch and linear precision, and establish their elementary properties. We
relate linear precision to the geometry of a particular linear projection,
giving necessary (and quite restrictive) conditions for a patch to possess
linear precision. A main focus is on linear precision for Krasauskas' toric
patches, which we show is equivalent to a certain rational map on CP^d being a
birational isomorphism. Lastly, we establish the connection between linear
presision for toric surface patches and maximum likelihood degree for discrete
exponential families in algebraic statistics, and show how iterative
proportional fitting may be used to compute toric patches.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:27:46 GMT"
},
{
"version": "v2",
"created": "Sat, 14 Jun 2008 17:28:11 GMT"
},
{
"version": "v3",
"created": "Wed, 4 Feb 2009 21:29:22 GMT"
}
] | 2009-02-04T00:00:00 | [
[
"Garcia-Puente",
"Luis",
""
],
[
"Sottile",
"Frank",
""
]
] |
0706.2117 | Kazuhiro Tanaka | Yuji Koike (Niigata University), Kazuhiro Tanaka (Juntendo University) | Novel Master Formula for Twist-3 Soft-Gluon-Pole Mechanism to Single
Transverse-Spin Asymmetry | 4 pages, 4 eps figures. To appear in the proceedings of 15th
International Workshop on Deep-Inelastic Scattering and Related Subjects
(DIS2007), Munich, Germany, 16-20 Apr 2007 | null | 10.1016/j.physletb.2008.09.026 | null | hep-ph | null | We prove that twist-3 soft-gluon-pole (SGP) cross section for single spin
asymmetries is determined by a certain ``primordial'' twist-2 cross section up
to kinematic and color factors in the leading order perturbative QCD. This
unveils universal structure behind the SGP cross sections in a variety of hard
processes, and also the special role of the scale invariance in the
corresponding primordial cross section, which leads to remarkable
simplification of the SGP cross sections for the production of massless
particle, such as those for pion production p^\uparrow p \to \pi X and
direct-photon production p^\uparrow p \to \gamma X.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:17:57 GMT"
}
] | 2015-06-30T00:00:00 | [
[
"Koike",
"Yuji",
"",
"Niigata University"
],
[
"Tanaka",
"Kazuhiro",
"",
"Juntendo University"
]
] |
0706.2118 | Antonio D\'iaz Ramos | Antonio Diaz | A method for integral cohomology of posets | 35 pages | null | null | null | math.AT | null | We present a method to compute integral cohomology of posets. This toolbox is
applicable as soon as the sub-posets under each object possess certain
structure. This is the case for simplicial complexes and simplex-like posets.
The method is based on homological algebra arguments in the category of
functors and on a spectral sequence built upon the poset. We show its relation
to discrete Morse theory. As application we give an alternative proof of Webb's
conjecture for saturated fusion systems and we compute the cohomology of
Coxeter complexes for finite and infinite Coxeter groups.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:19:36 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Diaz",
"Antonio",
""
]
] |
0706.2119 | Phuong Mai Dinh | F. Fehrer, P.M. Dinh, P.-G. Reinhard, and E. Suraud | Structural properties and optical response of Na clusters in Ne, Ar, and
Kr matrices | 9 pages, 3 figures, 1 table accepted in Phys. Rev. B | Phys. Rev. B 75, 235418 (2007) | 10.1103/PhysRevB.75.235418 | null | cond-mat.other | null | We discuss the structural properties and optical response of a small Na
cluster inside rare gas (RG) matrices of Ne, Ar, or Kr atoms. The mixed systems
are described with a hierarchical model, treating the cluster at a quantum
mechanical level and the matrix atoms classically in terms of their positions
and polarizations. We pay special attention to the differences caused by the
different matrix types. These differences can be explained by the interplay of
core repulsion and dipole attraction in the interaction between the cluster
electrons and the RG atoms.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:21:54 GMT"
}
] | 2007-06-25T00:00:00 | [
[
"Fehrer",
"F.",
""
],
[
"Dinh",
"P. M.",
""
],
[
"Reinhard",
"P. -G.",
""
],
[
"Suraud",
"E.",
""
]
] |
0706.2120 | Maarten Reyniers | M. Reyniers, G.C. Van de Steene, P.A.M. van Hoof, H. Van Winckel | IRAS08281-4850 and IRAS14325-6428: two A-type post-AGB stars with
s-process enrichment | 8 pages, 6 figures, accepted by A&A | null | 10.1051/0004-6361:20077607 | null | astro-ph | null | One of the puzzling findings in the study of the chemical evolution of
(post-)AGB stars is why very similar stars (in terms of metallicity, spectral
type, infrared properties, etc...) show a very different photospheric
composition. We aim at extending the still limited sample of s-process enriched
post-AGB stars, in order to obtain a statistically large enough sample that
allows us to formulate conclusions concerning the 3rd dredge-up occurrence. We
selected two post-AGB stars on the basis of IR colours indicative of a past
history of heavy mass loss: IRAS08281-4850 and IRAS14325-6428. They are cool
sources in the locus of the Planetary Nebulae (PNe) in the IRAS colour-colour
diagram. Abundances of both objects were derived for the first time on the
basis of high-quality UVES and EMMI spectra, using a critically compiled line
list with accurate log(gf) values, together with the latest Kurucz model
atmospheres. Both objects have very similar spectroscopically defined effective
temperatures of 7750-8000K. They are strongly carbon and s-process enriched,
with a C/O ratio of 1.9 and 1.6, and an [ls/Fe] of +1.7 and +1.2, for IRAS08281
and IRAS14325 resp. Moreover, the spectral energy distributions (SEDs) point to
heavy mass-loss during the preceding AGB phase. IRAS08281 and IRAS14325 are
prototypical post-AGB objects in the sense that they show strong post 3rd
dredge-up chemical enrichments. The neutron irradiation has been extremely
efficient, despite the only mild sub-solar metallicity. This is not conform
with the recent chemical models. The existence of very similar post-AGB stars
without any enrichment emphasizes our poor knowledge of the details of the AGB
nucleosynthesis and dredge-up phenomena. We call for a very systematic chemical
study of all cool sources in the PN region of the IRAS colour-colour diagram.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:23:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Reyniers",
"M.",
""
],
[
"Van de Steene",
"G. C.",
""
],
[
"van Hoof",
"P. A. M.",
""
],
[
"Van Winckel",
"H.",
""
]
] |
0706.2121 | Juha-Pekka Pellonpaa | Tuomas Hytonen, Juha-Pekka Pellonpaa, and Kari Ylinen | Diagonalization and representation results for nonpositive sesquilinear
form measures | J. Math. Anal. Appl., in press | J. Math. Anal. Appl. 338 (2008) 716-725 | 10.1016/j.jmaa.2007.05.063 | null | math.FA | null | We study decompositions of operator measures and more general sesquilinear
form measures $E$ into linear combinations of positive parts, and their
diagonal vector expansions. The underlying philosophy is to represent $E$ as a
trace class valued measure of bounded variation on a new Hilbert space related
to $E$. The choice of the auxiliary Hilbert space fixes a unique decomposition
with certain properties, but this choice itself is not canonical. We present
relations to Naimark type dilations and direct integrals.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:24:38 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Hytonen",
"Tuomas",
""
],
[
"Pellonpaa",
"Juha-Pekka",
""
],
[
"Ylinen",
"Kari",
""
]
] |
0706.2122 | Francesca Colaiori Dr | Francesca Colaiori, Gianfranco Durin, and Stefano Zapperi | Eddy current damping of a moving domain wall: beyond the quasistatic
approximation | 9 pages, 4 figures, submitted to Phys. Rev. B | null | 10.1103/PhysRevB.76.224416 | null | cond-mat.dis-nn cond-mat.mtrl-sci | null | In conducting ferromagnetic materials, a moving domain wall induces eddy
currents in the sample which give rise to an effective retarding pressure on
the domain wall. We show here that the pressure is not just proportional to the
instantaneous velocity of the wall, as often assumed in domain wall models, but
depends on the history of the motion. We calculate the retarding pressure by
solving the Maxwell equations for the field generated by the eddy currents, and
show how its effect can be accounted for by associating a negative effective
mass to the magnetic wall. We analyze the dependence of this effect on the
sample geometry and discuss the implications for Barkhausen noise measurements.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:35:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Colaiori",
"Francesca",
""
],
[
"Durin",
"Gianfranco",
""
],
[
"Zapperi",
"Stefano",
""
]
] |
0706.2123 | Nilton Penha Dr. | Nilton Penha, Bernhard Rothenstein and Doru Paunescu | Extending the abilities of the Minkowski spacetime diagram | 11 pages, 9 figures, June 14, 2007 | null | null | null | physics.gen-ph | null | A two-dimensional Minkowski spacetime diagram is neatly represented on a
Euclidean ordinary plane. However the Euclidean lengths of the lines on the
diagram do not correspond to the true values of physical quantities in
spacetime, except for those referring to the stationary reference frame. In
order to extend its abilities to other inertial reference frames, we derive a
factor which, multiplied by the magnitude of the actually displayed values (on
the diagram), leads to the corresponding true measured values by any other
inertial observers. Doing so, the student can infer from the Euclidean diagram
plot the expressions that account for Lorentz length contraction, time dilation
and also Lorentz Transformations just by using regular trigonometry.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:37:28 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Penha",
"Nilton",
""
],
[
"Rothenstein",
"Bernhard",
""
],
[
"Paunescu",
"Doru",
""
]
] |
0706.2124 | Po-Shen Loh | Po-Shen Loh, Benny Sudakov | Independent transversals in locally sparse graphs | 16 pages | null | null | null | math.CO | null | Let G be a graph with maximum degree \Delta whose vertex set is partitioned
into parts V(G) = V_1 \cup ... \cup V_r. A transversal is a subset of V(G)
containing exactly one vertex from each part V_i. If it is also an independent
set, then we call it an independent transversal. The local degree of G is the
maximum number of neighbors of a vertex v in a part V_i, taken over all choices
of V_i and v \not \in V_i. We prove that for every fixed \epsilon > 0, if all
part sizes |V_i| >= (1+\epsilon)\Delta and the local degree of G is o(\Delta),
then G has an independent transversal for sufficiently large \Delta. This
extends several previous results and settles (in a stronger form) a conjecture
of Aharoni and Holzman. We then generalize this result to transversals that
induce no cliques of size s. (Note that independent transversals correspond to
s=2.) In that context, we prove that parts of size |V_i| >=
(1+\epsilon)[\Delta/(s-1)] and local degree o(\Delta) guarantee the existence
of such a transversal, and we provide a construction that shows this is
asymptotically tight.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:42:11 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Loh",
"Po-Shen",
""
],
[
"Sudakov",
"Benny",
""
]
] |
0706.2125 | Ester Sola | E. Sola, J. Casulleras, J. Boronat | Quantized vortices in $^{\bf 4}$He droplets: a quantum Monte Carlo study | 4 pages, 3 figures | null | 10.1103/PhysRevB.76.052507 | null | cond-mat.other | null | We present a diffusion Monte Carlo study of a vortex line excitation attached
to the center of a $^4$He droplet at zero temperature. The vortex energy is
estimated for droplets of increasing number of atoms, from N=70 up to 300
showing a monotonous increase with $N$. The evolution of the core radius and
its associated energy, the core energy, is also studied as a function of $N$.
The core radius is $\sim 1$ \AA in the center and increases when approaching
the droplet surface; the core energy per unit volume stabilizes at a value 2.8
K$\sigma^{-3}$ ($\sigma=2.556$ \AA) for $N \ge 200$.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:42:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sola",
"E.",
""
],
[
"Casulleras",
"J.",
""
],
[
"Boronat",
"J.",
""
]
] |
0706.2126 | Thierry Cachat | Eugene Asarin (LIAFA), Thierry Cachat (LIAFA), Alexander Seliverstov
(IITP), Tayssir Touili (LIAFA), Vassily Lyubetsky (IITP) | Attenuation Regulation as a Term Rewriting System | to appear | Proceedings of the Second International Conference on Algebraic
Biology (06/07/2007) 12 | null | null | q-bio.QM | null | The classical attenuation regulation of gene expression in bacteria is
considered. We propose to represent the secondary RNA structure in the leader
region of a gene or an operon by a term, and we give a probabilistic term
rewriting system modeling the whole process of such a regulation.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 13:59:59 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Asarin",
"Eugene",
"",
"LIAFA"
],
[
"Cachat",
"Thierry",
"",
"LIAFA"
],
[
"Seliverstov",
"Alexander",
"",
"IITP"
],
[
"Touili",
"Tayssir",
"",
"LIAFA"
],
[
"Lyubetsky",
"Vassily",
"",
"IITP"
]
] |
0706.2127 | Sebastien Camalet | S. Camalet R. Chitra | Enhanced decoherence in the vicinity of a phase transition | null | null | null | null | cond-mat.mes-hall | null | We study the decoherence of a spin-1/2 induced by an environment which is on
the verge of a continuous phase transition. We consider spin environments
described by the ferromagnetic and antiferromagnetic Heisenberg models on a
square lattice. As is well known, these two dimensional systems undergo a
continuous phase transition at zero temperature, where, the spins order
spontaneously. For weak coupling of the central spin to these baths, we find
that as one approaches the transition temperature, critical fluctuations make
the central spin decohere faster. Furthermore, the decoherence is maximal at
zero temperature as signalled by the divergence of the Markovian decoherence
rate.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:02:39 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Chitra",
"S. Camalet R.",
""
]
] |
0706.2128 | Zsolt S\'andor | Zs. Sandor, W. Kley, P. Klagyivik | Stability and Formation of the Resonant System HD 73526 | 12 pages, 14 figures, accepted in A&A, v2: technical changes | null | 10.1051/0004-6361:20077345 | null | astro-ph | null | Based on radial velocity measurements it has been found recently that the two
giant planets detected around the star HD 73526 are in 2:1 resonance. However,
as our numerical integration shows, the derived orbital data for this system
result in chaotic behavior of the giant planets, which is uncommon among the
resonant extrasolar planetary systems.
We intend to present regular (non-chaotic) orbital solutions for the giant
planets in the system HD 73526 and offer formation scenarios based on combining
planetary migration and sudden perturbative effects such as planet-planet
scattering or rapid dispersal of the protoplanetary disk. A comparison with the
already studied resonant system HD 128311, exhibiting similar behavior, is also
done.
The new sets of orbital solutions have been derived by the Systemic Console
(www.oklo.org). The stability of these solutions has been investigated by the
Relative Lyapunov indicator, while the migration and scattering effects are
studied by gravitational N-body simulations applying non-conservative forces as
well. Additionally, hydrodynamic simulations of embedded planets in
protoplanetary disks are performed to follow the capture into resonance.
For the system HD 73526 we demonstrate that the observational radial velocity
data are consistent with a coplanar planetary system engaged in a stable 2:1
resonance exhibiting apsidal corotation. We have shown that, similarly to the
system HD 128311, the present dynamical state of HD 73526 could be the result
of a mixed evolutionary process melting together planetary migration and a
perturbative event.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:09:50 GMT"
},
{
"version": "v2",
"created": "Fri, 15 Jun 2007 11:42:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sandor",
"Zs.",
""
],
[
"Kley",
"W.",
""
],
[
"Klagyivik",
"P.",
""
]
] |
0706.2129 | Jerzy Lukierski | Sergey Fedoruk (BLTP JINR, Dubna), Jerzy Lukierski (Univ. Wroclaw) | Two-twistor Description of Membrane | LaTeX 8 pages, revtex4. V2: 4 references added, minor text
corrections | Phys.Rev.D76:066005,2007 | 10.1103/PhysRevD.76.066005 | null | hep-th | null | We describe D=4 twistorial membrane in terms of two twistorial
three-dimensional world volume fields. We start with the D-dimensional p-brane
generalizations of two phase space string formulations: the one with $p+1$
vectorial fourmomenta, and the second with tensorial momenta of $(p+1)$-th
rank. Further we consider tensionful membrane case in D=4. By using the
membrane generalization of Cartan-Penrose formula we express the fourmomenta by
spinorial fields and obtain the intermediate spinor-space-time formulation.
Further by expressing the worldvolume dreibein and the membrane space-time
coordinate fields in terms of two twistor fields one obtains the purely
twistorial formulation. It appears that the action is generated by a geometric
three-form on two-twistor space. Finally we comment on higher-dimensional (D>4)
twistorial p-brane models and their superextensions.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:10:28 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 10:57:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fedoruk",
"Sergey",
"",
"BLTP JINR, Dubna"
],
[
"Lukierski",
"Jerzy",
"",
"Univ. Wroclaw"
]
] |
0706.2130 | Juan Rojo | NNPDF Collaboration: J. Rojo, R. D. Ball, L. Del Debbio, S. Forte, A.
Guffanti, J. I. Latorre, A. Piccione and M. Ubiali | Progress on neural parton distributions | 4 pages, 2 figs, uses dis2007.cls, to appear in the DIS 2007 workshop
proceedings | null | null | null | hep-ph | null | We give a status report on the determination of a set of parton distributions
based on neural networks. In particular, we summarize the determination of the
nonsinglet quark distribution up to NNLO, we compare it with results obtained
using other approaches, and we discuss its use for a determination of
$\alpha_s$.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:15:45 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"NNPDF Collaboration",
"",
""
],
[
"Rojo",
"J.",
""
],
[
"Ball",
"R. D.",
""
],
[
"Del Debbio",
"L.",
""
],
[
"Forte",
"S.",
""
],
[
"Guffanti",
"A.",
""
],
[
"Latorre",
"J. I.",
""
],
[
"Piccione",
"A.",
""
],
[
"Ubiali",
"M.",
""
]
] |
0706.2131 | Robert Thorne S | R.S. Thorne, A. Sherstnev and C. Gwenlan | Parton Distributions for LO Calculations | 4 pages, 4 figures, Presented at 15th International Workshop on
Deep-Inelastic Scattering and Related Subjects (DIS2007), Munich, Germany,
16-20 Apr 2007 | null | null | null | hep-ph | null | We present a study of the results obtained combining LO partonic matrix
elements with different orders of partons distributions. These are compared to
the best prediction using NLO for both matrix elements and parton
distributions. The aim is to determine which parton distributions are most
appropriate to use in those cases where only LO matrix elements are available,
e.g. as in many Monte Carlo generators. Both LO and NLO parton distributions
have faults so a modified optimal LO set is suggested.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:37:27 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Thorne",
"R. S.",
""
],
[
"Sherstnev",
"A.",
""
],
[
"Gwenlan",
"C.",
""
]
] |
0706.2132 | Stefan Antusch | S. Antusch, L.E. Ibanez, T. Macri | Neutrino Masses and Mixings from String Theory Instantons | 24 pages, 2 figures | JHEP 0709:087,2007 | 10.1088/1126-6708/2007/09/087 | IFT-UAM/CSIC 07-35 | hep-ph hep-th | null | We study possible patterns of neutrino masses and mixings in string models in
which Majorana neutrino masses are generated by a certain class of string
theory instantons recently considered in the literature. These instantons may
generate either directly the dim=5 Weinberg operator or right-handed neutrino
Majorana masses, both with a certain flavour-factorised form. A hierarchy of
neutrino masses naturally appears from the exponentially suppressed
contributions of different instantons. The flavour structure is controlled by
string amplitudes involving neutrino fields and charged instanton zero modes.
For some simple choices for these amplitudes one finds neutrino mixing patterns
consistent with experimental results. In particular, we find that a
tri-bimaximal mixing pattern is obtained for simple symmetric values of the
string correlators.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:41:38 GMT"
}
] | 2009-01-06T00:00:00 | [
[
"Antusch",
"S.",
""
],
[
"Ibanez",
"L. E.",
""
],
[
"Macri",
"T.",
""
]
] |
0706.2133 | Xavier Barillier-Pertuisel | X. Barillier-Pertuisel, S. Pittel, L.Pollet, P. Schuck | Boson-Fermion pairing in Bose-Fermi mixtures on 1D optical lattices | accepted for publication by Phys. Rev. A | null | 10.1103/PhysRevA.77.012115 | null | cond-mat.other nucl-th | null | Boson-fermion pairing is considered in a discrete environment of bosons and
fully spin-polarized fermions, coupled via an attractive Bose-Fermi Hubbard
Hamiltonian in one dimension. The results of the T-matrix approximation for
particles of equal mass and at double half filling are compared with the
results of exact diagonalization and with Quantum Monte Carlo results.
Satisfactory agreement for most quantities is found. The appearance of a
stable, weak-coupling pairing mode is also confirmed.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:43:06 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 11:36:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Barillier-Pertuisel",
"X.",
""
],
[
"Pittel",
"S.",
""
],
[
"Pollet",
"L.",
""
],
[
"Schuck",
"P.",
""
]
] |
0706.2134 | Edward Conrad | J. Hass, F.Varchon, J. E. Millan-Otoya, M. Sprinkle, W.A. de Heer, C.
Berger, P.N. First, L. Magaud, and E.H. Conrad | Rotational stacking and its electronic effects on graphene films grown
on 4H-SiC$(000\bar{1})$ | 5 pages 4 figures | null | null | null | cond-mat.mtrl-sci | null | We examine the stacking order of multilayer graphene grown on the
SiC$(000\bar{1})$ surface using low-energy electron diffraction and surface
X-ray diffraction. We show that the films contain a high density of rotational
stacking faults caused by three types of rotated graphene: sheets rotated
$30^\circ$ and $\pm 2.20^\circ$ relative to the SiC substrate. These angles are
unique because they correspond to commensurate phases of layered graphene, both
with itself and with the SiC substrate. {\it Ab intio} calculations show that
these rotational phases electronically decouple adjacent graphene layers. The
band structure from graphene at fault boundaries displays linear energy
dispersion at the $K$-point (Dirac cones), nearly identical to that of a single
graphene sheet.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:44:02 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Hass",
"J.",
""
],
[
"Varchon",
"F.",
""
],
[
"Millan-Otoya",
"J. E.",
""
],
[
"Sprinkle",
"M.",
""
],
[
"de Heer",
"W. A.",
""
],
[
"Berger",
"C.",
""
],
[
"First",
"P. N.",
""
],
[
"Magaud",
"L.",
""
],
[
"Conrad",
"E. H.",
""
]
] |
0706.2135 | Jiri Cerny | Gerard Ben Arous, Anton Bovier and Jiri Cerny | Universality of the REM for dynamics of mean-field spin glasses | 30 pages, 1 fugre | null | null | null | math.PR cond-mat.dis-nn | null | We consider a version of a Glauber dynamics for a p-spin
Sherrington--Kirkpatrick model of a spin glass that can be seen as a time
change of simple random walk on the N-dimensional hypercube. We show that, for
any p>2 and any inverse temperature \beta>0, there exist constants g>0, such
that for all exponential time scales, $\exp(\gamma N)$, with $\gamma< g$, the
properly rescaled clock process (time-change process), converges to an
\alpha-stable subordinator where \alpha=\gamma/\beta^2<1. Moreover, the
dynamics exhibits aging at these time scales with time-time correlation
function converging to the arcsine law of this \alpha-stable subordinator. In
other words, up to rescaling, on these time scales (that are shorter than the
equilibration time of the system), the dynamics of p-spin models ages in the
same way as the REM, and by extension Bouchaud's REM-like trap model,
confirming the latter as a universal aging mechanism for a wide range of
systems. The SK model (the case p=2) seems to belong to a different
universality class.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:44:27 GMT"
}
] | 2007-07-17T00:00:00 | [
[
"Arous",
"Gerard Ben",
""
],
[
"Bovier",
"Anton",
""
],
[
"Cerny",
"Jiri",
""
]
] |
0706.2136 | Matthias Neubert | Matthias Neubert (Johannes Gutenberg University Mainz) | Factorization analysis for the fragmentation functions of hadrons
containing a heavy quark | 26 pages, 5 figures | null | null | MZ-TH/07-08 | hep-ph | null | Using methods of effective field theory, a systematic analysis of the
fragmentation functions D_{a/H}(x,m_Q) of a hadron H containing a heavy quark Q
is performed (with a=Q,Q_bar,q,q_bar,g). By integrating out pair production of
virtual and real heavy quarks, the fragmentation functions are matched onto a
single nonperturbative function describing the fragmentation of the heavy quark
Q into the hadron H in "partially quenched" QCD. All calculable, short-distance
dependence on x is extracted in this step. For x->1, the remaining
fragmentation function can be matched further onto a universal function defined
in heavy-quark effective theory in order to factor off its residual dependence
on the heavy-quark mass. By solving the evolution equation in the effective
theory analytically, large logarithms of the ratio mu/m_Q are resummed to all
orders in perturbation theory. Connections with existing approaches to
heavy-quark fragmentation are discussed. In particular, it is shown that
previous attempts to extract log^n(1-x) terms from the fragmentation function
D_{Q/H}(x,m_Q) are incompatible with a proper separation of short- and
long-distance effects.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:46:12 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Neubert",
"Matthias",
"",
"Johannes Gutenberg University Mainz"
]
] |
0706.2137 | Sonja Fritz | S. Fritz, J. Wilms, K. Pottschmidt, M. A. Nowak, E. Kendziorra, M. G.
Kirsch, I. Kreykenbohm, A. Santangelo | The broadband spectrum of Cygnus X-1 | 4 pages, 3 figures | null | null | null | astro-ph | null | The Black Hole (BH) binary Cygnus X-1 has been observed simultaneously by
INTEGRAL, RXTE, and XMM-Newton for four times in November and December 2004,
when Cyg X-1 became first observable with XMM-Newton. During these observations
the source was found in one of its transitional states between the hard state
and the soft state. We obtained a high signal to noise spectrum of Cyg X-1 from
3 keV to 1 MeV which allows us to put constraints on the nature of the
Comptonizing plasma by modeling the continuum with Comptonization models as
eqpair (Coppi 1992). Using XMM-Newton we were also able to confirm the presence
of a relativistically broadened Fe K-alpha line.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:48:10 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Fritz",
"S.",
""
],
[
"Wilms",
"J.",
""
],
[
"Pottschmidt",
"K.",
""
],
[
"Nowak",
"M. A.",
""
],
[
"Kendziorra",
"E.",
""
],
[
"Kirsch",
"M. G.",
""
],
[
"Kreykenbohm",
"I.",
""
],
[
"Santangelo",
"A.",
""
]
] |
0706.2138 | Laura Thevenard | Laura Thevenard (LPN), Audrey Miard (LPN), Laurent Vila (LPN),
Giancarlo Faini (LPN), Aristide Lema\^itre (LPN), Nicolas Vernier (LPS),
Jacques Ferr\'e (LPS), St\'ephane Fusil (UMP CNRS/THALES) | Magnetic patterning of (Ga,Mn)As by hydrogen passivation | null | null | 10.1063/1.2795790 | null | cond-mat.mtrl-sci | null | We present an original method to magnetically pattern thin layers of
(Ga,Mn)As. It relies on local hydrogen passivation to significantly lower the
hole density, and thereby locally suppress the carrier-mediated ferromagnetic
phase. The sample surface is thus maintained continuous, and the minimal
structure size is of about 200 nm. In micron-sized ferromagnetic dots
fabricated by hydrogen passivation on perpendicularly magnetized layers, the
switching fields can be maintained closer to the continuous film coercivity,
compared to dots made by usual dry etch techniques.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:48:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Thevenard",
"Laura",
"",
"LPN"
],
[
"Miard",
"Audrey",
"",
"LPN"
],
[
"Vila",
"Laurent",
"",
"LPN"
],
[
"Faini",
"Giancarlo",
"",
"LPN"
],
[
"Lemaître",
"Aristide",
"",
"LPN"
],
[
"Vernier",
"Nicolas",
"",
"LPS"
],
[
"Ferré",
"Jacques",
"",
"LPS"
],
[
"Fusil",
"Stéphane",
"",
"UMP CNRS/THALES"
]
] |
0706.2139 | Ansgar Reiners | Ansgar Reiners, Andreas Seifahrt, Hans Ulrich K\"aufl, Ralf
Siebenmorgen, Alain Smette | Spectral type dependent rotational braking and strong magnetic flux in
three components of the late-M multiple system LHS 1070 | accepted for publication as A&A Letter | null | 10.1051/0004-6361:20077964 | null | astro-ph | null | We show individual high resolution spectra of components A, B, and C of the
nearby late-M type multiple system LHS 1070. Component A is a mid-M star, B and
C are known to have masses at the threshold to brown dwarfs. From our spectra
we measure rotation velocities and the mean magnetic field for all three
components individually. We find magnetic flux on the order of several
kilo-Gauss in all components. The rotation velocities of the two late-M objects
B and C are similar (vsini = 16km/s), the earlier A component is spinning only
at about half that rate. This suggests weakening of net rotational braking at
late-M spectral type, and that the lack of slowly rotating late-M and L dwarfs
is real. Furthermore, we found that magnetic flux in the B component is about
twice as strong as in component C at similar rotation rate. This indicates that
rotational braking is not proportional to magnetic field strength in fully
convective objects, and that a different field topology is the reason for the
weak braking in low mass objects.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 14:57:13 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 07:37:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Reiners",
"Ansgar",
""
],
[
"Seifahrt",
"Andreas",
""
],
[
"Käufl",
"Hans Ulrich",
""
],
[
"Siebenmorgen",
"Ralf",
""
],
[
"Smette",
"Alain",
""
]
] |
0706.2140 | Zhi-Qiang Jiang | Zhi-Qiang Jiang, Wei-Xing Zhou (ECUST) | Multifractality in stock indexes: Fact or fiction? | 14 elsart pages including 6 eps figures | Physica A 387 (14), 3605-3614 (2008). | 10.1016/j.physa.2008.02.015 | null | q-fin.ST physics.soc-ph | null | Multifractal analysis and extensive statistical tests are performed upon
intraday minutely data within individual trading days for four stock market
indexes (including HSI, SZSC, S&P500, and NASDAQ) to check whether the indexes
(instead of the returns) possess multifractality. We find that the mass
exponent $\tau(q)$ is linear and the singularity $\alpha(q)$ is close to 1 for
all trading days and all indexes. Furthermore, we find strong evidence showing
that the scaling behaviors of the original data sets cannot be distinguished
from those of the shuffled time series. Hence, the so-called multifractality in
the intraday stock market indexes is merely an illusion.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:03:26 GMT"
}
] | 2008-12-02T00:00:00 | [
[
"Jiang",
"Zhi-Qiang",
"",
"ECUST"
],
[
"Zhou",
"Wei-Xing",
"",
"ECUST"
]
] |
0706.2141 | Mil\'an Mosonyi | Fumio Hiai, Milan Mosonyi, Tomohiro Ogawa | Large deviations and Chernoff bound for certain correlated states on a
spin chain | some typos corrected, short proof of Lemma A.2 added | J. Math. Phys. 48, 123301 (2007) | 10.1063/1.2812417 | null | math-ph math.MP quant-ph | null | In this paper we extend the results of Lenci and Rey-Bellet on the large
deviation upper bound of the distribution measures of local Hamiltonians with
respect to a Gibbs state, in the setting of translation-invariant finite-range
interactions. We show that a certain factorization property of the reference
state is sufficient for a large deviation upper bound to hold and that this
factorization property is satisfied by Gibbs states of the above kind as well
as finitely correlated states. As an application of the methods the Chernoff
bound for correlated states with factorization property is studied. In the
specific case of the distributions of the ergodic averages of a one-site
observable with respect to an ergodic finitely correlated state the spectral
theory of positive maps is applied to prove the full large deviation principle.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:03:59 GMT"
},
{
"version": "v2",
"created": "Sat, 1 Sep 2007 14:41:53 GMT"
},
{
"version": "v3",
"created": "Mon, 25 Feb 2008 07:41:41 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hiai",
"Fumio",
""
],
[
"Mosonyi",
"Milan",
""
],
[
"Ogawa",
"Tomohiro",
""
]
] |
0706.2142 | Vasily E. Tarasov | Vasily E. Tarasov | Path Integral for Quantum Operations | 24 pages, LaTeX | Journal of Physics A. Vol.37. No.9. (2004) 3241-3257 | 10.1088/0305-4470/37/9/013 | null | quant-ph | null | In this paper we consider a phase space path integral for general
time-dependent quantum operations, not necessarily unitary. We obtain the path
integral for a completely positive quantum operation satisfied Lindblad
equation (quantum Markovian master equation). We consider the path integral for
quantum operation with a simple infinitesimal generator.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:11:43 GMT"
}
] | 2015-03-10T00:00:00 | [
[
"Tarasov",
"Vasily E.",
""
]
] |
0706.2143 | Robert Young | Robert J. Young, Samuel J. Dewhurst, R. Mark Stevenson, Paola
Atkinson, Anthony J. Bennett, Martin B. Ward, Ken Cooper, David A. Ritchie,
Andrew J. Shields | Single electron-spin memory with a semiconductor quantum dot | 7 pages, 4 figures | null | 10.1088/1367-2630/9/10/365 | null | quant-ph | null | We show storage of the circular polarisation of an optical field,
transferring it to the spin-state of an individual electron confined in a
single semiconductor quantum dot. The state is subsequently readout through the
electronically-triggered emission of a single photon. The emitted photon shares
the same polarisation as the initial pulse but has a different energy, making
the transfer of quantum information between different physical systems
possible. With an applied magnetic field of 2 Tesla, spin memory is preserved
for at least 1000 times more than the exciton's radiative lifetime.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:30:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Young",
"Robert J.",
""
],
[
"Dewhurst",
"Samuel J.",
""
],
[
"Stevenson",
"R. Mark",
""
],
[
"Atkinson",
"Paola",
""
],
[
"Bennett",
"Anthony J.",
""
],
[
"Ward",
"Martin B.",
""
],
[
"Cooper",
"Ken",
""
],
[
"Ritchie",
"David A.",
""
],
[
"Shields",
"Andrew J.",
""
]
] |
0706.2144 | Monica Id\`a | Alessandro Gimigliano, Brian Harbourne, Monica Id\`a | The role of the cotangent bundle in resolving ideals of fat points in
the plane | 17 pages | null | null | null | math.AG | null | We study the connection between the generation of a fat point scheme
supported at general points in the plane and the behaviour of the cotangent
bundle with respect to some rational curves particularly relevant for the
scheme. We put forward two conjectures, giving examples and partial results in
support of them.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:28:01 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Gimigliano",
"Alessandro",
""
],
[
"Harbourne",
"Brian",
""
],
[
"Idà",
"Monica",
""
]
] |
0706.2145 | Dalibor Nosek | J.Ridky, D.Nosek, P.Travnicek, P.Necesal | Prompt muons in extended air showers | Contribution to the 30th International Cosmic Ray Conference, Merida,
Mexico; 4 pages, 3 figures | null | null | null | astro-ph | null | We present results of simulations of a muon content in the air showers
induced by very high energy cosmic rays. Muon energy distributions and muon
densities at ground level are given. We discuss a prompt muon component
generated by decays of charm mesons. The method combines standard Monte Carlo
generators incorporated in the CORSIKA code and phenomenological estimates of
the charm hadroproduction.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:57:47 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 16:18:25 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Ridky",
"J.",
""
],
[
"Nosek",
"D.",
""
],
[
"Travnicek",
"P.",
""
],
[
"Necesal",
"P.",
""
]
] |
0706.2146 | Rajesh Sudarsan | Rajesh Sudarsan and Calvin J. Ribbens | Efficient Multidimensional Data Redistribution for Resizable Parallel
Computations | 18 pages, 12 figures, 2 tables. A shorter version of this paper is
available in the proceedings of the The Fifth International Symposium on
Parallel and Distributed Processing and Applications (ISPA07) | null | null | null | cs.DC | null | Traditional parallel schedulers running on cluster supercomputers support
only static scheduling, where the number of processors allocated to an
application remains fixed throughout the execution of the job. This results in
under-utilization of idle system resources thereby decreasing overall system
throughput. In our research, we have developed a prototype framework called
ReSHAPE, which supports dynamic resizing of parallel MPI applications executing
on distributed memory platforms. The resizing library in ReSHAPE includes
support for releasing and acquiring processors and efficiently redistributing
application state to a new set of processors. In this paper, we derive an
algorithm for redistributing two-dimensional block-cyclic arrays from $P$ to
$Q$ processors, organized as 2-D processor grids. The algorithm ensures a
contention-free communication schedule for data redistribution if $P_r \leq
Q_r$ and $P_c \leq Q_c$. In other cases, the algorithm implements circular row
and column shifts on the communication schedule to minimize node contention.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:54:10 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Sudarsan",
"Rajesh",
""
],
[
"Ribbens",
"Calvin J.",
""
]
] |
0706.2147 | Arthur Jaffe | Arthur Jaffe and David Moser | Replica Condensation and Tree Decay | null | null | null | null | math-ph hep-th math.MP | null | We give an intuitive method--using local, cyclic replica symmetry--to isolate
exponential tree decay in truncated (connected) correlations. We give an
expansion and use the symmetry to show that all terms vanish, except those
displaying {\em replica condensation}. The condensation property ensures
exponential tree decay.
We illustrate our method in a low-temperature Ising system, but expect that
one can use a similar method in other random field and quantum field problems.
While considering the illustration, we prove an elementary upper bound on the
entropy of random lattice surfaces.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:49:17 GMT"
}
] | 2007-06-20T00:00:00 | [
[
"Jaffe",
"Arthur",
""
],
[
"Moser",
"David",
""
]
] |
0706.2148 | Carla Figueira de Morisson Faria | C. Figueira de Morisson Faria | High-harmonic generation in diatomic molecules: a quantum-orbit analysis
of the interference patterns | 14 pages, 9 figures; two figures have been modified, one figure and
new results included, discussions extended | null | null | null | physics.atom-ph | null | We perform a detailed analysis of high-order harmonic generation in diatomic
molecules within the strong-field approximation, with emphasis on
quantum-interference effects. Specifically, we investigate how the different
types of electron orbits, involving one or two centers, affect the interference
patterns in the spectra. We also briefly address the influence of the choice of
gauge, and of the initial and final electronic bound states on such patterns.
For the length-gauge SFA and undressed bound states, there exist additional
terms, which can be interpreted as potential energy shifts. If, on the one
hand, such shifts alter the potential barriers through which the electron
initially tunnels, and may lead to a questionable physical interpretation of
the features encountered, on the other hand they seem to be necessary in order
to reproduce the overall maxima and minima in the spectra. Indeed, for dressed
electronic bound states in the length gauge, or undressed bound states in the
velocity gauge, for which such shifts are absent, there is a breakdown of the
interference patterns. In order to avoid such a problem, we provide an
alternative pathway for the electron to reach the continuum, by means of an
additional attosecond-pulse train. A comparison of the purely monochromatic
case with the situation for which the attosecond pulses are present suggests
that the patterns are due to the interference between the electron orbits which
finish at different centers, regardless of whether one or two centers are
involved.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:50:24 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 13:49:06 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Faria",
"C. Figueira de Morisson",
""
]
] |
0706.2149 | Pierre Pugnat | Pierre Pugnat | A New Comment on "Experimental Observation of Optical Rotation Generated
in Vacuum by a Magnetic Field" | 1 page, 1 figure, Comment to the article published in Phys. Rev.
Lett. 96, 110406 (2006) by E. Zavattini et al | null | null | null | hep-ex | null | One of the magneto-optical properties of the mirrors of the Fabry-Perot
cavity used for the experiment is considered as a possible origin of the PVLAS
measurement result.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:57:05 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Pugnat",
"Pierre",
""
]
] |
0706.2150 | Alexei Kniazev | N. Brosch (1,2), A. Kniazev (2,3), D. Buckley (2), D. O'Donoghue (2),
Y. Hashimoto (2), N. Loaring (2), E. Romero (2), M. Still (2), P. Vaisanen
(2), E.B. Burgh (4), K. Nordsieck (4) ((1) Wise Observatory, Israel; (2)
SAAO, South Africa; (3) SAO, Russia; (4) University of Wisconsin; USA) | The polar ring galaxy AM1934-563 revisited | 19 pages, 13 figures, submitted to MNRAS. Some figures were bitmapped
to reduce the size. Full resolution version is available from
http://www.saao.ac.za/~akniazev/pub/AM1934_563.pdf | null | 10.1111/j.1365-2966.2007.12488.x | null | astro-ph | null | We report long-slit spectroscopic observations of the dust-lane polar-ring
galaxy AM1934-563 obtained with the Southern African Large Telescope (SALT)
during its performance-verification phase. The observations target the spectral
region of the Ha, [NII] and [SII] emission-lines, but show also deep NaI
stellar absorption lines that we interpret as produced by stars in the galaxy.
We derive rotation curves along the major axis of the galaxy that extend out to
about 8 kpc from the center for both the gaseous and the stellar components,
using the emission and absorption lines. We derive similar rotation curves
along the major axis of the polar ring and point out differences between these
and the ones of the main galaxy. We identify a small diffuse object visible
only in Ha emission and with a low velocity dispersion as a dwarf HII galaxy
and argue that it is probably metal-poor. Its velocity indicates that it is a
fourth member of the galaxy group in which AM1934-563 belongs. We discuss the
observations in the context of the proposal that the object is the result of a
major merger and point out some observational discrepancies from this
explanation. We argue that an alternative scenario that could better fit the
observations may be the slow accretion of cold intergalactic gas, focused by a
dense filament of galaxies in which this object is embedded (abridged).
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 15:58:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Brosch",
"N.",
""
],
[
"Kniazev",
"A.",
""
],
[
"Buckley",
"D.",
""
],
[
"O'Donoghue",
"D.",
""
],
[
"Hashimoto",
"Y.",
""
],
[
"Loaring",
"N.",
""
],
[
"Romero",
"E.",
""
],
[
"Still",
"M.",
""
],
[
"Vaisanen",
"P.",
""
],
[
"Burgh",
"E. B.",
""
],
[
"Nordsieck",
"K.",
""
]
] |
0706.2151 | Richard Woodard | S. Deser (Caltech and Brandeis) and R. P. Woodard (U. of Florida) | Nonlocal Cosmology | Expanded(!) version, to appear in Phys. Rev. Letters | Phys.Rev.Lett.99:111301,2007 | 10.1103/PhysRevLett.99.111301 | UFIFT-QG-07-03 | astro-ph gr-qc hep-th | null | We explore nonlocally modified models of gravity, inspired by quantum loop
corrections, as a mechanism for explaining current cosmic acceleration. These
theories enjoy two major advantages: they allow a delayed response to cosmic
events, here the transition from radiation to matter dominance, and they avoid
the usual level of fine tuning; instead, emulating Dirac's dictum, the required
large numbers come from the large time scales involved. Their solar system
effects are safely negligible, and they may even prove useful to the black hole
information problem.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:01:39 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 12:41:50 GMT"
}
] | 2011-05-31T00:00:00 | [
[
"Deser",
"S.",
"",
"Caltech and Brandeis"
],
[
"Woodard",
"R. P.",
"",
"U. of Florida"
]
] |
0706.2152 | Pavel Etingof | Pavel Etingof and Xiaoguang Ma | On elliptic Dunkl operators | 9 pages, latex | null | null | null | math.QA math.RT | null | We attach elliptic Dunkl operators to an abelian variety with a finite group
action. This generalizes elliptic Dunkl operators for Weyl groups, defined by
Buchstaber, Felder, and Veselov in 1994. We show that these operators commute,
and use them to define representations from category O of elliptic Cherednik
algebras. We also consider the monodromy representations of differential
equations defined by elliptic Dunkl operators, and show that they yield finite
dimensional rrepresentations of generalized double affine Hecke algebras.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:01:47 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Etingof",
"Pavel",
""
],
[
"Ma",
"Xiaoguang",
""
]
] |
0706.2153 | Quentin Merigot | Fr\'ed\'eric Chazal (INRIA Sophia Antipolis), David Cohen-Steiner
(INRIA Sophia Antipolis), Quentin M\'erigot (INRIA Sophia Antipolis) | Stability of boundary measures | null | Boundary measures for geometric inference, Found. Comput. Math.,
10 (2), pp. 221-240, 2010 | 10.1007/s10208-009-9056-2 | null | cs.CG math.CA math.MG | null | We introduce the boundary measure at scale r of a compact subset of the
n-dimensional Euclidean space. We show how it can be computed for point clouds
and suggest these measures can be used for feature detection. The main
contribution of this work is the proof a quantitative stability theorem for
boundary measures using tools of convex analysis and geometric measure theory.
As a corollary we obtain a stability result for Federer's curvature measures of
a compact, allowing to compute them from point-cloud approximations of the
compact.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:03:28 GMT"
},
{
"version": "v2",
"created": "Mon, 18 Jun 2007 09:06:56 GMT"
}
] | 2010-03-31T00:00:00 | [
[
"Chazal",
"Frédéric",
"",
"INRIA Sophia Antipolis"
],
[
"Cohen-Steiner",
"David",
"",
"INRIA Sophia Antipolis"
],
[
"Mérigot",
"Quentin",
"",
"INRIA Sophia Antipolis"
]
] |
0706.2154 | M. Domokos | M. Domokos | Vector invariants of a class of pseudo-reflection groups and
multisymmetric syzygies | Joining the contents of math.RT/0602303v3 and math.RT/0611430v1 plus
some additional material | Journal of Lie Theory 19 (2009), 507-525 | null | null | math.RT math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | First and second fundamental theorems are given for polynomial invariants of
a class of pseudo-reflection groups (including the Weyl groups of type $B_n$),
under the assumption that the order of the group is invertible in the base
field. Special case of the result is a finite presentation of the algebra of
multisymmetric polynomials. Reducedness of the invariant commuting scheme is
proved as a by-product. The algebra of multisymmetric polynomials over an
arbitrary base ring is revisited.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:06:35 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Feb 2015 16:29:57 GMT"
}
] | 2015-02-12T00:00:00 | [
[
"Domokos",
"M.",
""
]
] |
0706.2155 | Greg Sepesi | Greg Sepesi | Dualheap Selection Algorithm: Efficient, Inherently Parallel and
Somewhat Mysterious | 5 pages, 6 figures | null | null | null | cs.DS cs.CC cs.DC | null | An inherently parallel algorithm is proposed that efficiently performs
selection: finding the K-th largest member of a set of N members. Selection is
a common component of many more complex algorithms and therefore is a widely
studied problem.
Not much is new in the proposed dualheap selection algorithm: the heap data
structure is from J.W.J.Williams, the bottom-up heap construction is from R.W.
Floyd, and the concept of a two heap data structure is from J.W.J. Williams and
D.E. Knuth. The algorithm's novelty is limited to a few relatively minor
implementation twists: 1) the two heaps are oriented with their roots at the
partition values rather than at the minimum and maximum values, 2)the coding of
one of the heaps (the heap of smaller values) employs negative indexing, and 3)
the exchange phase of the algorithm is similar to a bottom-up heap
construction, but navigates the heap with a post-order tree traversal.
When run on a single processor, the dualheap selection algorithm's
performance is competitive with quickselect with median estimation, a common
variant of C.A.R. Hoare's quicksort algorithm. When run on parallel processors,
the dualheap selection algorithm is superior due to its subtasks that are
easily partitioned and innately balanced.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:11:24 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Sepesi",
"Greg",
""
]
] |
0706.2156 | Michael Gronau | Michael Gronau | Direct CP Violation in B Decays | corrected typo and added references | ECONFC070512:007,2007 | null | PSN: fpcp07_143 | hep-ph hep-ex | null | We discuss several aspects of direct CP asymmetries in B decays, which are
very useful in spite of hadronic uncertainties in asymmetry calculations. 1)
Asymmetries in decays to $D^{(*)}K^{(*)}$, $\pi^+\pi^-, \rho^+\rho^-$,
providing precision tests for the CKM phase $\gamma$. 2) Null tests in $B^+\to
J/\psi K^+, \pi^+\pi^0$, where a nonzero asymmetry provides evidence for New
Physics. 3) Isospin and broken flavor SU(3) relations among CP asymmetries in
$B\to K\pi, \pi\pi$ predicting $A_{CP}(B^0\to K^0\pi^0)$ and $A_{CP}(B^0\to
\pi^0\pi^0)$. 4) The significance of $A_{CP}(B^0\to K^+\pi^-)\ne A_{CP}(B^+\to
K^+\pi^0)$. 5) A potentially stringent constraint on $\gamma$ from
$A_{CP}(B^+\to K^+\pi^0)$ and $R_c\equiv 2\Gamma(B^+\to K^+\pi^0)/\Gamma(B^+\to
K^0\pi^+)$. 6) The role of direct CP asymmetries in $b\to s\bar qq$ decays for
studying the origin of potential New Physics.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:26:43 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Jun 2007 12:14:17 GMT"
},
{
"version": "v3",
"created": "Tue, 10 Jul 2007 15:23:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gronau",
"Michael",
""
]
] |
0706.2157 | Haibin Zhao | H. B. Zhao, K. J. Smith, Y. Fan, G. L\"upke, A. Bhattacharya, S. D.
Bader, M. Warusawithana, X. Zhai, J. N. Eckstein | Viscous spin exchange torque on precessional magnetization in
$(\mathrm{LaMnO}_3)_{2n}/(\mathrm{SrMnO}_3)_{n}$ superlattices | 5 pages, 4 figures | null | 10.1103/PhysRevLett.100.117208 | null | cond-mat.mtrl-sci cond-mat.str-el | null | Photoinduced magnetization dynamics is investigated in chemically ordered
$(\mathrm{LaMnO}_3)_{2n}/(\mathrm{SrMnO}_3)_n$ superlattices using the
time-resolved magneto-optic Kerr effect. A monotonic frequency-field dependence
is observed for the $n=1$ superlattice, indicating a single spin population
consistent with a homogeneous hole distribution. In contrast, for $n\geq2$
superlattices, a large precession frequency is observed at low fields
indicating the presence of an exchange torque in the dynamic regime. We propose
a model that ascribes the emergence of exchange torque to the coupling between
two spin populations -- viscous and fast spins.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:55:04 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Zhao",
"H. B.",
""
],
[
"Smith",
"K. J.",
""
],
[
"Fan",
"Y.",
""
],
[
"Lüpke",
"G.",
""
],
[
"Bhattacharya",
"A.",
""
],
[
"Bader",
"S. D.",
""
],
[
"Warusawithana",
"M.",
""
],
[
"Zhai",
"X.",
""
],
[
"Eckstein",
"J. N.",
""
]
] |
0706.2158 | Roberto Aloisio | R. Aloisio, V. Berezinsky, A. Gazizov | Ultra High Energy Cosmic Rays Diffusion in an Expanding Universe | To appear in the proceedings of 30th International Cosmic Ray
Conference (ICRC 2007), Merida, Yucatan, Mexico, 3-11 Jul 2007 | null | null | null | astro-ph | null | We study the solution of the diffusion equation for Ultra-High Energy Cosmic
Rays in the general case of an expanding universe, comparing it with the well
known Syrovatsky solution obtained in the more restrictive case of a static
universe. The formal comparison of the two solutions with all parameters being
fixed identically reveals an appreciable discrepancy. This discrepancy is less
important if in both models a different set of best-fit parameters is used.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:51:18 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Aloisio",
"R.",
""
],
[
"Berezinsky",
"V.",
""
],
[
"Gazizov",
"A.",
""
]
] |
0706.2159 | Jonathan Silman | N. Aharon, S. Machnes, B. Reznik, J. Silman and L. Vaidman | Continuous input nonlocal games | Journal version, slight modifications | Natural Computing 12, 5 (2013) | 10.1007/s11047-012-9354-5 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a family of nonlocal games in which the inputs the players receive
are continuous. We study three representative members of the family. For the
first two a team sharing quantum correlations (entanglement) has an advantage
over any team restricted to classical correlations. We conjecture that this is
true for the third member of the family as well.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 16:57:14 GMT"
},
{
"version": "v2",
"created": "Sun, 17 Mar 2013 21:45:48 GMT"
}
] | 2013-03-19T00:00:00 | [
[
"Aharon",
"N.",
""
],
[
"Machnes",
"S.",
""
],
[
"Reznik",
"B.",
""
],
[
"Silman",
"J.",
""
],
[
"Vaidman",
"L.",
""
]
] |
0706.2160 | Menachem Shlossberg | Menachem Shlossberg | Minimality in topological groups and Heisenberg type groups | 11 pages | null | null | null | math.GN math.GR | null | We study relatively minimal subgroups in topological groups. We find, in
particular, some natural relatively minimal subgroups in unipotent groups which
are defined over "good" rings. By "good" rings we mean archimedean absolute
valued (not necessarily associative) division rings. Some of the classical
rings which we consider besides the field of reals are the ring of quaternions
and the ring of octonions. This way we generalize in part a previous result
which was obtained by Dikranjan and Megrelishvili and involved the Heisenberg
group.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:02:27 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Shlossberg",
"Menachem",
""
]
] |
0706.2161 | L. M. Duan | L.-M. Duan | General Hubbard model for strongly interacting fermions in an optical
lattice and its phase detection | 5 pages, 4 figures | null | 10.1209/0295-5075/81/20001 | null | cond-mat.other cond-mat.supr-con | null | Based on consideration of the system symmetry and its Hilbert space, we show
that strongly interacting fermions in an optical lattice or superlattice can be
generically described by a lattice resonance Hamiltonian. The latter can be
mapped to a general Hubbard model with particle assisted tunneling rates. We
investigate the model under population imbalance and show the attractive and
the repulsive models have the same complexity in phase diagram under the
particle-hole mapping. Using this mapping, we propose an experimental method to
detect possible exotic superfluid/magnetic phases for this system.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:02:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Duan",
"L. -M.",
""
]
] |
0706.2162 | Thomas Prellberg | J Krawczyk, A L Owczarek, T Prellberg | The competition of hydrogen-like and isotropic interactions on polymer
collapse | null | null | 10.1088/1742-5468/2007/09/P09016 | null | cond-mat.soft cond-mat.stat-mech | null | We investigate a lattice model of polymers where the nearest-neighbour
monomer-monomer interaction strengths differ according to whether the local
configurations have so-called ``hydrogen-like'' formations or not. If the
interaction strengths are all the same then the classical $\theta$-point
collapse transition occurs on lowering the temperature, and the polymer enters
the isotropic liquid-drop phase known as the collapsed globule. On the other
hand, strongly favouring the hydrogen-like interactions give rise to an
anisotropic folded (solid-like) phase on lowering the temperature. We use Monte
Carlo simulations up to a length of 256 to map out the phase diagram in the
plane of parameters and determine the order of the associated phase
transitions. We discuss the connections to semi-flexible polymers and other
polymer models. Importantly, we demonstrate that for a range of energy
parameters two phase transitions occur on lowering the temperature, the second
being a transition from the globule state to the crystal state. We argue from
our data that this globule-to-crystal transition is continuous in two
dimensions in accord with field-theory arguments concerning Hamiltonian walks,
but is first order in three dimensions.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:08:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Krawczyk",
"J",
""
],
[
"Owczarek",
"A L",
""
],
[
"Prellberg",
"T",
""
]
] |
0706.2163 | Marek Karliner | Marek Karliner, Boaz Keren-Zur, Harry J. Lipkin and Jonathan L. Rosner | Predictions for masses of Xi_b baryons | Figure annotation amended | null | null | EFI 07-16, TAUP 2857/07, WIS/09/07-JUNE-DPP, ANL-HEP-PR-07-4 | hep-ph hep-ex | null | The recent observation by CDF of Sigma_b^{+-} (uub and ddb) baryons within 2
MeV of the predicted Sigma_b - Lambda_b splitting has provided strong
confirmation for the theoretical approach based on modeling the color hyperfine
interaction. We now apply this approach to predict the masses of the Xi_b
family of baryons with quark content usb and dsb - the ground state Xi_b at
5790 to 5800 MeV, and the excited states Xi_b^' and Xi_b^*. The main source of
uncertainty is the method used to estimate the mass difference m_b - m_c from
known hadrons. We verify that corrections due to the details of the interquark
potential and to Xi_b-Xi_b^' mixing are small.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:25:38 GMT"
},
{
"version": "v2",
"created": "Mon, 18 Jun 2007 19:39:27 GMT"
},
{
"version": "v3",
"created": "Tue, 19 Jun 2007 14:49:15 GMT"
},
{
"version": "v4",
"created": "Tue, 19 Jun 2007 20:01:14 GMT"
},
{
"version": "v5",
"created": "Sat, 23 Jun 2007 16:24:19 GMT"
}
] | 2007-06-23T00:00:00 | [
[
"Karliner",
"Marek",
""
],
[
"Keren-Zur",
"Boaz",
""
],
[
"Lipkin",
"Harry J.",
""
],
[
"Rosner",
"Jonathan L.",
""
]
] |
0706.2164 | Casey Papovich | Casey Papovich (1), Gregory Rudnick (3), Emeric Le Floc'h (1,3),
Pieter G. van Dokkum (4), George H. Rieke (1), Edward N. Taylor (5), Lee
Armus (6), Eric Gawiser (4), Jiasheng Huang (7), Delphine Marcillac (1),
Marijn Franx (5) ((1) Steward Observatory, (2) NOAO, (3) IfA, (4) Yale, (5)
Leiden Observatory, (6) SSC/Caltech, (7) CfA) | Spitzer Mid-to-Far-Infrared Flux Densities of Distant Galaxies | Accepted for Publication in ApJ. AASTeX format. 34 pages, 12 figures.
Updated references and other small textual revisions | null | 10.1086/521090 | null | astro-ph | null | We study the infrared (IR) properties of high-redshift galaxies using deep
Spitzer 24, 70, and 160 micron data. Our primary interest is to improve the
constraints on the total IR luminosities, L(IR), of these galaxies. We combine
the Spitzer data in the southern Extended Chandra Deep Field with a
K-band-selected galaxy sample and photometric redshifts from the
Multiwavelength Survey by Yale-Chile. We used a stacking analysis to measure
the average 70 and 160 micron flux densities of 1.5 < z < 2.5 galaxies as a
function of 24 micron flux density, X-ray activity, and rest-frame near-IR
color. Galaxies with 1.5 < z < 2.5 and S(24)=53-250 micro-Jy have L(IR) derived
from their average 24-160 micron flux densities within factors of 2-3 of those
derived from the 24 micron flux densities only. However, L(IR) derived from the
average 24-160 micron flux densities for galaxies with S(24) > 250 micro-Jy and
1.5 < z < 2.5 are lower than those derived using only the 24 micron flux
density by factors of 2-10. Galaxies with S(24) > 250 micro-Jy have S(70)/S(24)
flux ratios comparable to sources with X-ray detections or red rest-frame IR
colors, suggesting that warm dust possibly heated by AGN may contribute to the
high 24 micron emission. Based on the average 24-160 micron flux densities,
nearly all 24 micron-selected galaxies at 1.5 < z < 2.5 have L(IR) < 6 x 10^12
solar luminosities, which if attributed to star formation corresponds to < 1000
solar masses per year. This suggests that high redshift galaxies may have
similar star formation efficiencies and feedback processes as local analogs.
Objects with L(IR) > 6 x 10^12 solar luminosities are quite rare, with a
surface density ~ 30 +/- 10 per sq. deg, corresponding to ~ 2 +/- 1 x 10^-6
Mpc^-3 over 1.5 < z < 2.5.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:23:32 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jun 2007 13:55:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Papovich",
"Casey",
""
],
[
"Rudnick",
"Gregory",
""
],
[
"Floc'h",
"Emeric Le",
""
],
[
"van Dokkum",
"Pieter G.",
""
],
[
"Rieke",
"George H.",
""
],
[
"Taylor",
"Edward N.",
""
],
[
"Armus",
"Lee",
""
],
[
"Gawiser",
"Eric",
""
],
[
"Huang",
"Jiasheng",
""
],
[
"Marcillac",
"Delphine",
""
],
[
"Franx",
"Marijn",
""
]
] |
0706.2165 | Sarah McKagan | S. B. McKagan, W. Handley, K. K. Perkins, C. E. Wieman | A Research-Based Curriculum for Teaching the Photoelectric Effect | submitted to American Journal of Physics | American Journal of Physics 77, 87 (2009) | 10.1119/1.2978181 | null | physics.ed-ph | null | Physics faculty consider the photoelectric effect important, but many
erroneously believe it is easy for students to understand. We have developed
curriculum on this topic including an interactive computer simulation,
interactive lectures with peer instruction, and conceptual and mathematical
homework problems. Our curriculum addresses established student difficulties
and is designed to achieve two learning goals, for students to be able to (1)
correctly predict the results of photoelectric effect experiments, and (2)
describe how these results lead to the photon model of light. We designed two
exam questions to test these learning goals. Our instruction leads to better
student mastery of the first goal than either traditional instruction or
previous reformed instruction, with approximately 85% of students correctly
predicting the results of changes to the experimental conditions. On the
question designed to test the second goal, most students are able to correctly
state both the observations made in the photoelectric effect experiment and the
inferences that can be made from these observations, but are less successful in
drawing a clear logical connection between the observations and inferences.
This is likely a symptom of a more general lack of the reasoning skills to
logically draw inferences from observations.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:04:49 GMT"
}
] | 2017-04-19T00:00:00 | [
[
"McKagan",
"S. B.",
""
],
[
"Handley",
"W.",
""
],
[
"Perkins",
"K. K.",
""
],
[
"Wieman",
"C. E.",
""
]
] |
0706.2166 | Joseph H. Silverman | Shu Kawaguchi and Joseph H. Silverman | Canonical heights and the arithmetic complexity of morphisms on
projective space | submitted to the Quarterly Journal of Pure and Applied Mathematics | Pure and Applied Mathematics Quarterly 5 (2009), 1201--1217 | null | null | math.NT math.DS | null | Let F and G be morphisms of degree at least 2 from P^N to P^N that are
defined over the algebraic closure of Q. We define the arithmetic distance
d(F,G) between F and G to be the supremum over all algebraic points P of
|h_F(P)-h_G(P)|, where h_F and h_G are the canonical heights associated to the
morphisms F and G, respectively. We prove comparison theorems relating d(F,G)
to more naive height functions and show that for a fixed G, the set of F
satisfying d(F,G) < B is a set of bounded height. In particular, there are only
finitely many such F defined over any given number field.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:38:45 GMT"
}
] | 2011-05-30T00:00:00 | [
[
"Kawaguchi",
"Shu",
""
],
[
"Silverman",
"Joseph H.",
""
]
] |
0706.2167 | Michael Wohlgenannt | Harald Grosse and Michael Wohlgenannt | Renormalization and Induced Gauge Action on a Noncommutative Space | 20 pages; to appear in the proceedings of the 21st Nishinomiya-Yukawa
Memorial Symposium Noncommutative geometry and quantum spacetime in physics,
Nishinomiya and Kyoto (Japan), 2006 | Prog.Theor.Phys.Suppl.171:161-177,2007 | 10.1143/PTPS.171.161 | UWThPh-2007-14 | hep-th | null | Field theories on deformed spaces suffer from the IR/UV mxing and
renormalization is generically spoiled. In work with R. Wulkenhaar, one of us
realized a way to cure this desease by adding one more marginal operator. We
review these ideas, show the application to $\phi^3$ models and use heat kernel
expansion methods for a scalar field theory coupled to an external gauge field
on a $\theta$-deformed space and derive noncommutative gauge actions.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:54:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Grosse",
"Harald",
""
],
[
"Wohlgenannt",
"Michael",
""
]
] |
0706.2168 | Mu-Chun Chen | Mu-Chun Chen | Models of Neutrino Masses and Mixing | Talk presented at the 2nd International Colliders to Cosmic Rays
Conference (C2CR07), Lake Tahoe, CA, February 25 - March 1, 2007; 8 pages; 2
figures | AIPConf.Proc.928:153-160,2007 | 10.1063/1.2775909 | UCI-TR-2007-27, FERMILAB-CONF-07-200-T | hep-ph | null | Neutrino physics has entered an era of precision measurements. With these
precise measurements, we may be able to distinguish different models that have
been constructed to explain the small neutrino masses and the large mixing
among them. In this talk, I review some of the existing theoretical models and
their predictions for neutrino oscillations.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:45:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chen",
"Mu-Chun",
""
]
] |
0706.2169 | Joseph H. Silverman | Shu Kawaguchi and Joseph H. Silverman | Nonarchimedean Green functions and dynamics on projective space | 30 pages. Minor corrections and updated references | Math. Zeit. 262 (2009), 173--197 | null | null | math.NT math.DS | null | Let F: P^N_K --> P^N_K be a morphism of degree d > 1 defined over a field K
that is algebraically closed and complete with respect to a nonarchimedean
absolute value. We prove that a modified Green function G_F associated to F is
Holder continuous on P^N(K) and that the Fatou set F is equal to the set of
points at which G_F is locally constant. Further, G_F vanishes precisely on the
set of points P such that F has good reduction at every point in the forward
orbit of P. We also prove that the iterates of F are locally uniformly
Lipschitz on the Fatou set of F.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:54:02 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Jul 2007 12:53:58 GMT"
}
] | 2011-05-30T00:00:00 | [
[
"Kawaguchi",
"Shu",
""
],
[
"Silverman",
"Joseph H.",
""
]
] |
0706.2170 | Alexandre Oliveira | J. E. Steiner, A. S. Oliveira, C. A. O. Torres and A. Damineli | Transient jets in V617 Sagittarii | Four pages, accepted to be published as a Letter in A&A | null | 10.1051/0004-6361:20077847 | null | astro-ph | null | Some of the luminous Compact Binary Supersoft X-Ray sources (CBSS) have shown
indications of jets, also called satellites due to their appearance in the
spectra. In V Sagittae (V Sge) stars, the galactic counterparts of the CBSS,
such features have been reported only for WX Cen. If V Sge stars are indeed the
analogs of CBSS, one may expect transient jet emission in other objects of this
class. Spectroscopic observations of the V Sge star V617 Sgr have been made,
both at high photometric state and at decline. We show that V617 Sgr presents
Halpha satellites at high photometric state with velocities of +/-780 km/s.
This feature confirms, once more, the CBSS nature of the V Sge stars, however
the details of the spectral characteristics also suggest that the two groups of
stars display some intrinsic spectroscopic differences, which are likely to be
due to a selection effect related to chemical abundance.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:55:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Steiner",
"J. E.",
""
],
[
"Oliveira",
"A. S.",
""
],
[
"Torres",
"C. A. O.",
""
],
[
"Damineli",
"A.",
""
]
] |
0706.2171 | Diego Mardones | Guido Garay, Diego Mardones, Kate J. Brooks, Liza Videla, Yanett
Contreras | A multiwavelength study of young massive star forming regions: II. The
dust environment | 6 figures, accepted by ApJ | Astrophys.J.666:309-320,2007 | 10.1086/520103 | null | astro-ph | null | We present observations of 1.2-mm dust continuum emission, made with the
Swedish ESO Submillimeter Telescope, towards eighteen luminous IRAS point
sources, all with colors typical of compact HII regions and associated with
CS(2-1) emission, thought to be representative of young massive star forming
regions. Emission was detected toward all the IRAS objects. We find that the
1.2-mm sources associated with them have distinct physical parameters, namely
sizes of 0.4 pc, dust temperatures of 30 K, masses of 2x10^3 Msun, column
densities of 3x10^23 cm^-2, and densities of 4x10^5 cm^-3. We refer to these
dust structures as massive and dense cores. Most of the 1.2-mm sources show
single-peaked structures, several of which exhibit a bright compact peak
surrounded by a weaker extended envelope. The observed radial intensity
profiles of sources with this type of morphology are well fitted with power-law
intensity profiles with power-law indices in the range 1.0-1.7. This result
indicates that massive and dense cores are centrally condensed, having radial
density profiles with power-law indices in the range 1.5-2.2. We also find that
the UC HII regions detected with ATCA towards the IRAS sources investigated
here (Paper I) are usually projected at the peak position of the 1.2-mm dust
continuum emission, suggesting that massive stars are formed at the center of
the centrally condensed massive and dense cores.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:00:59 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Garay",
"Guido",
""
],
[
"Mardones",
"Diego",
""
],
[
"Brooks",
"Kate J.",
""
],
[
"Videla",
"Liza",
""
],
[
"Contreras",
"Yanett",
""
]
] |
0706.2172 | Yazid Delenda | Yazid Delenda | Dijet Azimuthal Correlations in QCD Hard Processes | 4 pages, 2 figures. To appear in the proceedings of DIS 2007, Munich,
Germany, 16-20 April 2007. Added 2 reference | null | null | MAN/HEP/2007/10 | hep-ph | null | We study the azimuthal correlation distribution for dijet production in QCD
hard processes. This observable is sensitive to soft and/or collinear emissions
in the back-to-back region, giving rise to single and double logarithms. We
provide resummed predictions to NLL accuracy for both DIS at HERA and hadronic
collisions at Tevatron and perform a NLO matching to NLOJET++ results in the
DIS case.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:33:21 GMT"
},
{
"version": "v2",
"created": "Fri, 15 Jun 2007 11:22:10 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Delenda",
"Yazid",
""
]
] |
0706.2173 | Bruno Coppi | B. Coppi | Theoretical Resolution of Magnetic Reconnection in High Energy Plasmas | To be published in "Collective Phenomena in Macroscopic Systems",
Eds. G. Bertin, et al., Publ. World Scientific, 2007. Preprinted here with
the permission of the editors | null | 10.1142/9789812778901_0007 | null | physics.plasm-ph physics.space-ph | null | The formation of macroscopic reconnected magnetic structures (islands) have
been observed in advanced experiments on weakly collisional, well confined
plasmas while established theories of the drift-tearing modes, which depend
strongly on the electron temperature gradient and can describe the formation of
these structures, had predicted practically inaccessible excitation thresholds
for them in these regimes. The relevant theoretical dilemma is resolved as
mesoscopic modes that depend critically on the ratio of the transverse (to the
magnetic field) to the longitudinal thermal
conductivity${D^e_{\perp}/D^e_{\|}$, can produce large scale magnetic
reconnection. These modes are envisioned to emerge from a background, which can
be coherent, of collisionless microscopic reconnecting modes driven by the
electron temperature gradient, that create a sequence of adjacent strings of
magnetic islands and increase considerably the ratio ${D^e_{\perp}/D^e_{\|}$
over its classical value. The mesoscopic reconnecting mode is treated by a
singular perturbation analysis involving three asymptotic regions and the small
parameters ${(D^e_{\perp}/D^e_{\|})}^{1/4}$ and ${\epsilon}^{1/4}_{*}$, where
${\epsilon}_{*} {\equiv}D_m/D_A$, $D_m$ is the magnetic diffusion coefficient,
$D_A\sim\texttt{v}^{2}_{A}r_{Te}/(D_Bk_{\perp})$,
$r_{Te}\equiv(-d\texttt{ln}T_e/dr)^{-1}$, $k_{\perp}$ is the transverse mode
number, $\texttt{v}^{2}_{A}=B^{2}/(4\pi{nm}_{i})}$ and $D_B=cT_e/(eB)$.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:38:11 GMT"
}
] | 2017-08-23T00:00:00 | [
[
"Coppi",
"B.",
""
]
] |
0706.2174 | Christophe Lovis | C. Lovis and M. Mayor | Planets around evolved intermediate-mass stars. I. Two substellar
companions in the open clusters NGC 2423 and NGC 4349 | 9 pages, 11 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20077375 | null | astro-ph | null | Context. Many efforts are being made to characterize extrasolar planetary
systems and unveil the fundamental mechanisms of planet formation. An important
aspect of the problem, which remains largely unknown, is to understand how the
planet formation process depends on the mass of the parent star. In particular,
as most planets discovered to date orbit a solar-mass primary, little is known
about planet formation around more massive stars. Aims. To investigate this
point, we present first results from a radial velocity planet search around red
giants in the clump of intermediate-age open clusters. We choose clusters
harbouring red giants with masses between 1.5 and 4 M_sun, using the well-known
cluster parameters to accurately determine the stellar masses. We are therefore
exploring a poorly-known domain of primary masses, which will bring new
insights into the properties of extrasolar planetary systems. Methods. We are
following a sample of about 115 red giants with the Coralie and HARPS
spectrographs to obtain high-precision radial velocity (RV) measurements and
detect giant planets around these stars. We use bisector and activity index
diagnostics to distinguish between planetary-induced RV variations and stellar
photospheric jitter. Results. We present the discoveries of a giant planet and
a brown dwarf in the open clusters NGC 2423 and NGC 4349, orbiting the 2.4
M_sun-star NGC2423 No3 (TYC 5409-2156-1) and the 3.9 M_sun-star NGC4349 No127
(TYC 8975-2606-1). These low-mass companions have orbital periods of 714 and
678 days and minimum masses of 10.6 and 19.8 M_jup, respectively. Combined with
the other known planetary systems, these detections indicate that the frequency
of massive planets is higher around intermediate-mass stars, and therefore
probably scales with the mass of the protoplanetary disk.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:43:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lovis",
"C.",
""
],
[
"Mayor",
"M.",
""
]
] |
0706.2175 | P. Goerss | P. Goerss, H.-W. Henn, M. Mahowald, and C. Rezk | A resolution of the K(2)-local sphere at the prime 3 | 46 pages, published version | Ann. of Math. (2) 162 (2005), no. 2, 777--822 | null | null | math.AT | null | We develop a framework for displaying the stable homotopy theory of the
sphere, at least after localization at the second Morava K-theory K(2). At the
prime 3, we write the spectrum L_{K(2)S^0 as the inverse limit of a tower of
fibrations with four layers. The successive fibers are of the form E_2^hF where
F is a finite subgroup of the Morava stabilizer group and E_2 is the second
Morava or Lubin-Tate homology theory. We give explicit calculation of the
homotopy groups of these fibers. The case n=2 at p=3 represents the edge of our
current knowledge: n=1 is classical and at n=2, the prime 3 is the largest
prime where the Morava stabilizer group has a p-torsion subgroup, so that the
homotopy theory is not entirely algebraic.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 18:50:12 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Goerss",
"P.",
""
],
[
"Henn",
"H. -W.",
""
],
[
"Mahowald",
"M.",
""
],
[
"Rezk",
"C.",
""
]
] |
0706.2176 | Elias Gyftopoulos | Elias P. Gyftopoulos, Michael R. von Spakovsky | Comments on the breakdown of the Landauer bound for information erasure
in the quantum regime | 2 pages | null | null | null | quant-ph | null | Upon reviewing the article by Allahverdyan and Nieuwenhuizen in PRE, we
conclude that neither the Landauer principle nor the counterexamples presented
by the authors have any relation (i) to thermodynamics, and (ii) to the
interdependence of nonstatistical quantum physics and thermodynamics.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:14:29 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Gyftopoulos",
"Elias P.",
""
],
[
"von Spakovsky",
"Michael R.",
""
]
] |
0706.2177 | Tomasz Klimczuk | T. Klimczuk, F. Ronning, V. Sidorov, R. J. Cava and J.D. Thompson | Physical properties of the noncentrosymmetric superconductor
Mg_10Ir_19B_16 | Text and figures revised. One author and point contact tunneling data
added | Phys. Rev. Lett. 99, 257004 (2007) | 10.1103/PhysRevLett.99.257004 | null | cond-mat.supr-con | null | Specific heat, electrical resistivity, and magnetic susceptibility
measurements on a high quality sample of Mg10Ir19B16 provide a self-consistent
determination of its superconducting properties. They indicate that Mg10Ir19B16
is a type-II superconductor (Tc=4.45K, k(0)=20), with an electron-phonon
coupling constant l_ep=0.66. An analysis of the T-dependent specific heat shows
that superconducting properties are dominated by an s-wave gap (D=0.7 meV).
Point contact tunneling data provide evidence for multiple superconducting
gaps, as expected from strong asymmetric spin-orbit coupling.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:29:59 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Jan 2008 22:41:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Klimczuk",
"T.",
""
],
[
"Ronning",
"F.",
""
],
[
"Sidorov",
"V.",
""
],
[
"Cava",
"R. J.",
""
],
[
"Thompson",
"J. D.",
""
]
] |
0706.2178 | Francisco C. Alcaraz | Francisco C. Alcaraz and Matheus J. Lazo | Exactly solvable interacting vertex models | 20 pages, 3 figures | J. Stat. Mech. P08008 (2007) | 10.1088/1742-5468/2007/08/P08008 | null | cond-mat.stat-mech cond-mat.str-el | null | We introduce and solvev a special family of integrable interacting vertex
models that generalizes the well known six-vertex model. In addition to the
usual nearest-neighbor interactions among the vertices, there exist extra
hard-core interactions among pair of vertices at larger distances.The
associated row-to-row transfer matrices are diagonalized by using the recently
introduced matrix product {\it ansatz}. Similarly as the relation of the
six-vertex model with the XXZ quantum chain, the row-to-row transfer matrices
of these new models are also the generating functions of an infinite set of
commuting conserved charges. Among these charges we identify the integrable
generalization of the XXZ chain that contains hard-core exclusion interactions
among the spins. These quantum chains already appeared in the literature. The
present paper explains their integrability.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:34:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Alcaraz",
"Francisco C.",
""
],
[
"Lazo",
"Matheus J.",
""
]
] |
0706.2179 | Francisco Diego Mazzitelli | Diana L\'opez Nacir and Francisco D. Mazzitelli | Backreaction in trans-Planckian cosmology: renormalization, trace
anomaly and selfconsistent solutions | 19 pages, 3 figures | Phys.Rev.D76:024013,2007 | 10.1103/PhysRevD.76.024013 | null | gr-qc hep-th | null | We analyze the semiclassical Einstein equations for quantum scalar fields
satisfying modified dispersion relations. We first discuss in detail the
renormalization procedure based on adiabatic subtraction and dimensional
regularization. We show that, contrary to what expected from power counting
arguments, in 3+1 dimensions the subtraction involves up to the fourth
adiabatic order even for dispersion relations containing higher powers of the
momentum. Then we analyze the dependence of the trace of the renormalized
energy momentum tensor with the scale of new physics, and we recover the usual
trace anomaly in the appropriate limit. We also find selfconsistent de Sitter
solutions for dispersion relations that contain up to the fourth power of the
momentum. Using this particular example, we also discuss the possibility that
the modified dispersion relation can be mimicked at lower energies by an
effective initial state in a theory with the usual dispersion relation.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:34:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Nacir",
"Diana López",
""
],
[
"Mazzitelli",
"Francisco D.",
""
]
] |
0706.2180 | Tomasz Klimczuk | C. Sulkowski, T. Klimczuk, R. J. Cava, and K. Rogacki | The effect of Fe and Ru substitution for Ni on the thermopower in
MgCNi_3 | 14 pages, 4 figures | Physical Review B vol. 76 (2007) 060501(R) | 10.1103/PhysRevB.76.060501 | null | cond-mat.supr-con cond-mat.mtrl-sci | null | The intermetallic perovskite MgCNi3 is a superconductor with a Tc=7 K.
Substitution of Fe and Ru for Ni decreases Tc monotonically as the doping
concentration is increased. Here we report thermopower measurements, S(T), on
MgCNi3, MgCNi3-xFex and MgCNi3-xRux. For MgCNi3, the thermopower is negative, -
12.5 mikroV/K, at 300 K. The absolute value of S decreases as x increases in
MgCNi3-xFex and MgCNi3-xRux. The sign of S changes from negative to positive at
low temperatures for values of x > 0.01. These data show that the carriers in
MgCNi3 are electrons, and by increasing x and decreasing temperature, the
participation of hole carriers clearly increases. The influence of the magnetic
moments of the Fe atoms on the thermopower is not visible.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:35:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sulkowski",
"C.",
""
],
[
"Klimczuk",
"T.",
""
],
[
"Cava",
"R. J.",
""
],
[
"Rogacki",
"K.",
""
]
] |
0706.2181 | Graciela B. Gelmini | Graciela B Gelmini, Oleg Kalashev and Dmitry V. Semikoz | GZK Photons Above 10 EeV | 20 pages, 9 figures (21 panels), iopart.cls and iopart12.clo needed
to typeset | JCAP 0711:002,2007 | 10.1088/1475-7516/2007/11/002 | null | astro-ph | null | We calculate the flux of "GZK-photons", namely the flux of photons produced
by extragalactic nucleons through the resonant photoproduction of pions, the so
called GZK effect. This flux depends on the UHECR spectrum on Earth, of the
spectrum of nucleons emitted at the sources, which we characterize by its slope
and maximum energy, on the distribution of sources and on the intervening
cosmological backgrounds, in particular the magnetic field and radio
backgrounds. For the first time we calculate the GZK photons produced by
nuclei. We calculate the possible range of the GZK photon fraction of the total
UHECR flux for the AGASA and the HiRes spectra. We find that for nucleons
produced at the sources it could be as large as a few % and as low as 10^{-4}
above 10 EeV. For nuclei produced at the sources the maximum photon fraction is
a factor of 2 to 3 times smaller above 10 EeV but the minimum could be much
smaller than for nucleons. We also comment on cosmogenic neutrino fluxes.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:41:37 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Gelmini",
"Graciela B",
""
],
[
"Kalashev",
"Oleg",
""
],
[
"Semikoz",
"Dmitry V.",
""
]
] |
0706.2182 | Alexander Bolonkin | Alexander Bolonkin | New AB-Thermonuclear Reactor for Aerospace | 21 pages, 10 figures, 5 tables | null | null | null | physics.gen-ph physics.atom-ph | null | There are two main methods of nulcear fusion: inertial confinement fusion
(ICF) and magnetic confinement fusion (MCF). Existing thermonuclear reactors
are very complex, expensive, large, and heavy. They cannot achieve the Lawson
creterion.
The author offers an innovation. ICF has on the inside surface of the
shell-shaped combustion chamber a covering of small Prism Reflectors (PR) and
plasma reflector. These prism reflectors have a noteworthy advantage, in
comparison with conventional mirror and especially with conventional shell:
they multi-reflect the heat and laser radiation exactly back into collision
with the fuel target capsule (pellet). The plasma reflector reflects the
Bremsstrahlung radiation.
The offered innovation decreases radiation losses, creates significant
radiation pressure and increases the reaction time. The Lawson criterion
increases by hundreds of times. The size, cost, and weight of a typical
installation will decrease by tens of times.
The author is researching the efficiency of these innovations. Keywords:
Thermonuclear reactor, Multi-reflex AB-thermonuclear reactor, aerospace
thermonuclear engine.
This work is presented as paper AIAA-2006-7225 to Space-2006 Conference,
19-21 September, 2006, San Jose, CA, USA.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:45:49 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Bolonkin",
"Alexander",
""
]
] |
0706.2183 | Peter Petreczky | Agnes Mocsy (RBRC), Peter Petreczky (BNL) | Color Screening Melts Quarkonium | 4 pages. version to be published in Phys. Rev. Lett | Phys.Rev.Lett.99:211602,2007 | 10.1103/PhysRevLett.99.211602 | BNL-NT 07/26, RBRC-683 | hep-ph | null | We calculate quarkonium spectral functions in a quark-gluon plasma using a
potential model based on full QCD lattice calculations of the free energy of
static quark-antiquark pair. We estimate the binding energy and the thermal
width of different quarkonium states. The estimated upper limit for the
dissociation temperatures is considerably lower than the ones suggested in the
recent literature.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:52:18 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Nov 2007 20:58:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mocsy",
"Agnes",
"",
"RBRC"
],
[
"Petreczky",
"Peter",
"",
"BNL"
]
] |
0706.2184 | Jorgen Ellegaard Andersen | Jorgen Ellegaard Andersen | Mapping Class Groups do not have Kazhdan's Property (T) | null | null | null | null | math.QA math.GR math.GT | null | We prove that the mapping class group of a closed oriented surface of genus
at least two does not have Kazhdan's property (T).
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 19:54:32 GMT"
}
] | 2007-06-15T00:00:00 | [
[
"Andersen",
"Jorgen Ellegaard",
""
]
] |
0706.2185 | Valeri Kotov | Valeri N. Kotov, Bruno Uchoa, A. H. Castro Neto | Electron-Electron Interactions in the Vacuum Polarization of Graphene | 5 pages, 2 figures; published version | Physical Review B 78, 035119 (2008) | 10.1103/PhysRevB.78.035119 | null | cond-mat.str-el | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the effect of electron-electron interactions on the static
polarization properties of graphene beyond RPA. Divergent self-energy
corrections are naturally absorbed into the renormalized coupling constant
$\alpha$. We find that the lowest order vertex correction, which is the first
non-trivial correlation contribution, is finite, and about 30% of the RPA
result at strong coupling $\alpha \sim 1$. The vertex correction leads to
further reduction of the effective charge. Finite contributions to dielectric
screening are expected in all orders of perturbation theory.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 19:33:35 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jun 2007 19:41:33 GMT"
},
{
"version": "v3",
"created": "Mon, 19 Nov 2007 23:26:32 GMT"
},
{
"version": "v4",
"created": "Wed, 4 Jun 2008 21:01:03 GMT"
}
] | 2008-07-18T00:00:00 | [
[
"Kotov",
"Valeri N.",
""
],
[
"Uchoa",
"Bruno",
""
],
[
"Neto",
"A. H. Castro",
""
]
] |
0706.2186 | Dragan Huterer | Michael S. Turner and Dragan Huterer (KICP, University of Chicago) | Cosmic Acceleration, Dark Energy and Fundamental Physics | 10 pages, 8 figures, invited review for Journal of the Physical
Society of Japan, in press | J.Phys.Soc.Jap.76:111015,2007 | 10.1143/JPSJ.76.111015 | null | astro-ph gr-qc hep-th | null | A web of interlocking observations has established that the expansion of the
Universe is speeding up and not slowing, revealing the presence of some form of
repulsive gravity. Within the context of general relativity the cause of cosmic
acceleration is a highly elastic (p\sim -rho), very smooth form of energy
called ``dark energy'' accounting for about 75% of the Universe. The
``simplest'' explanation for dark energy is the zero-point energy density
associated with the quantum vacuum; however, all estimates for its value are
many orders-of-magnitude too large. Other ideas for dark energy include a very
light scalar field or a tangled network of topological defects. An alternate
explanation invokes gravitational physics beyond general relativity.
Observations and experiments underway and more precise cosmological
measurements and laboratory experiments planned for the next decade will test
whether or not dark energy is the quantum energy of the vacuum or something
more exotic, and whether or not general relativity can self consistently
explain cosmic acceleration. Dark energy is the most conspicuous example of
physics beyond the standard model and perhaps the most profound mystery in all
of science.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:00:36 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 19:01:06 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Turner",
"Michael S.",
"",
"KICP, University of Chicago"
],
[
"Huterer",
"Dragan",
"",
"KICP, University of Chicago"
]
] |
0706.2187 | T. Senthil | Ribhu K. Kaul, Yong Baek Kim, Subir Sachdev, T. Senthil | Algebraic charge liquids | 6+8 pages, 2 figures; (v2) Rewritten for broader accessibility; (v3)
corrected numerical error in Eq. (5) | Nature Physics 4, 28 (2008) | 10.1038/nphys790 | null | cond-mat.str-el cond-mat.supr-con | null | High temperature superconductivity emerges in the cuprate compounds upon
changing the electron density of an insulator in which the electron spins are
antiferromagnetically ordered. A key characteristic of the superconductor is
that electrons can be extracted from them at zero energy only if their momenta
take one of four specific values (the `nodal points'). A central enigma has
been the evolution of the zero energy electrons in the metallic state between
the antiferromagnet and the superconductor, and recent experiments yield
apparently contradictory results. The oscillation of the resistance in this
metal as a function of magnetic field indicate that the zero energy electrons
carry momenta which lie on elliptical `Fermi pockets', while ejection of
electrons by high intensity light indicates that the zero energy electrons have
momenta only along arc-like regions. We present a theory of new states of
matter, which we call `algebraic charge liquids', which arise naturally between
the antiferromagnet and the superconductor, and reconcile these observations.
Our theory also explains a puzzling dependence of the density of
superconducting electrons on the total electron density, and makes a number of
unique predictions for future experiments.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 18:06:50 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Sep 2007 14:54:53 GMT"
},
{
"version": "v3",
"created": "Mon, 3 Dec 2007 06:19:14 GMT"
}
] | 2008-01-06T00:00:00 | [
[
"Kaul",
"Ribhu K.",
""
],
[
"Kim",
"Yong Baek",
""
],
[
"Sachdev",
"Subir",
""
],
[
"Senthil",
"T.",
""
]
] |
0706.2188 | Jane MacGibbon | Jane H MacGibbon | Black Hole Constraints on Varying Fundamental Constants | 5 pages, published version | Phys.Rev.Lett.99:061301,2007 | 10.1103/PhysRevLett.99.061301 | null | astro-ph gr-qc hep-th | null | Here we apply the Generalized Second Law of Thermodynamics and derive upper
limits on the variation in the fundamental constants. The maximum variation in
the electronic charge permitted for black holes accreting and emitting in the
present cosmic microwave background corresponds to a variation in the fine
structure constant of ((Delta alpha) / alpha) ~ 2 x 10^-23 per second. This
value matches the variation measured by Webb et al. using absorption lines in
the spectra of distant quasars and suggests the variation mechanism may be a
coupling between the electron and the cosmic photon background.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:03:34 GMT"
},
{
"version": "v2",
"created": "Mon, 13 Aug 2007 18:42:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"MacGibbon",
"Jane H",
""
]
] |
0706.2189 | Brian Nord | B.Nord, R. Stanek, E. Rasia, A.E. Evrard | Effects of Selection and Covariance on X-ray Scaling Relations of Galaxy
Clusters | 5pages, 4 Figures, Submitted to MNRAS | null | 10.1111/j.1745-3933.2007.00407.x | null | astro-ph | null | We explore how the behavior of galaxy cluster scaling relations are affected
by flux-limited selection biases and intrinsic covariance among observable
properties. Our models presume log-normal covariance between luminosity (L) and
temperature (T) at fixed mass (M), centered on evolving, power-law mean
relations as a function of host halo mass. Selection can mimic evolution; the
\lm and \lt relations from shallow X-ray flux-limited samples will deviate from
mass-limited expectations at nearly all scales while the relations from deep
surveys ($10^{-14} \cgsflux$) become complete, and therefore unbiased, at
masses above $\sims 2 \times 10^{14} \hinv \msol$. We derive expressions for
low-order moments of the luminosity distribution at fixed temperature, and show
that the slope and scatter of the \lt relation observed in flux-limited samples
is sensitive to the assumed \lt correlation coefficient. In addition, \lt
covariance affects the redshift behavior of halo counts and mean luminosity in
a manner that is nearly degenerate with intrinsic population evolution.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:20:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nord",
"B.",
""
],
[
"Stanek",
"R.",
""
],
[
"Rasia",
"E.",
""
],
[
"Evrard",
"A. E.",
""
]
] |
0706.2190 | Igor Zutic | Igor Zutic, Jaroslav Fabian, and Steven C. Erwin | Bipolar spintronics: From spin injection to spin-controlled logic | 16 pages, 7 figures | J. Phys.: Condens. Matter 19 (2007) 165219 (23pp) | 10.1088/0953-8984/19/16/165219 | null | cond-mat.other | null | An impressive success of spintronic applications has been typically realized
in metal-based structures which utilize magnetoresistive effects for
substantial improvements in the performance of computer hard drives and
magnetic random access memories. Correspondingly, the theoretical understanding
of spin-polarized transport is usually limited to a metallic regime in a linear
response, which, while providing a good description for data storage and
magnetic memory devices, is not sufficient for signal processing and digital
logic. In contrast, much less is known about possible applications of
semiconductor-based spintronics and spin-polarized transport in related
structures which could utilize strong intrinsic nonlinearities in
current-voltage characteristics to implement spin-based logic. Here we discuss
the challenges for realizing a particular class of structures in semiconductor
spintronics: our proposal for bipolar spintronic devices in which carriers of
both polarities (electrons and holes) contribute to spin-charge coupling. We
formulate the theoretical framework for bipolar spin-polarized transport, and
describe several novel effects in two- and three-terminal structures which
arise from the interplay between nonequilibrium spin and equilibrium
magnetization.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 17:30:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zutic",
"Igor",
""
],
[
"Fabian",
"Jaroslav",
""
],
[
"Erwin",
"Steven C.",
""
]
] |
0706.2191 | Robert D. Pisarski | Larry McLerran and Robert D. Pisarski | Phases of Dense Quarks at Large N_c | 23 pages, 2 figures, uses entcs macro. Minor changes in wording | Nucl.Phys.A796:83-100,2007 | 10.1016/j.nuclphysa.2007.08.013 | null | hep-ph | null | In the limit of a large number of colors, N_c, we suggest that gauge theories
can exhibit several distinct phases at nonzero temperature and quark density.
Two are familiar: a cold, dilute phase of confined hadrons, where the pressure
is ~ 1, and a hot phase of deconfined quarks and gluons, with pressure ~ N_c^2.
When the quark chemical potential mu ~ 1, the deconfining transition
temperature, T_d, is independent of mu. For T < T_d, as mu increases above the
mass threshold, baryons quickly form a dense phase where the pressure is ~ N_c.
As illustrated by a Skyrme crystal, chiral symmetry can be both spontaneously
broken, and then restored, in the dense phase. While the pressure is ~ N_c,
like that of (non-ideal) quarks, the dense phase is still confined, with
interactions near the Fermi surface those of baryons, and not of quarks. Thus
in the chirally symmetric region, baryons near the Fermi surface are parity
doubled. We suggest possible implications for the phase diagram of QCD.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:22:50 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 00:43:36 GMT"
},
{
"version": "v3",
"created": "Fri, 10 Aug 2007 21:27:37 GMT"
}
] | 2010-04-06T00:00:00 | [
[
"McLerran",
"Larry",
""
],
[
"Pisarski",
"Robert D.",
""
]
] |
0706.2192 | Peter A. Sturrock | P.A. Sturrock and M.S. Wheatland | Analysis and packaging of radiochemical solar neutrino data. 1. Bayesian
approach | 8 pages | SolarPhys.247:217-224,2008 | 10.1007/s11207-007-9112-5 | null | hep-ph astro-ph gr-qc | null | According to current practice, the results of each run of a radiochemical
solar neutrino experiment comprise an estimate of the flux and upper and lower
error estimates. These estimates are derived by a maximum-likelihood procedure
from the times of decay events in the analysis chamber. This procedure has the
following shortcomings: (a) Published results sometimes include negative flux
estimates. (b) Even if the flux estimate is non-negative, the probability
distribution function implied by the flux and error estimates will extend into
negative territory; and (c) The overall flux estimate derived from the results
of a sequence of runs may differ substantially from an estimate made by a
global analysis of all of the timing data taken together. These defects
indicate that the usual packaging of data in radiochemical solar neutrino
experiments provides an inadequate summary of the data, which implies a loss of
information. This article reviews this problem from a Bayesian perspective, and
suggests an alternative scheme for the packaging of radiochemical solar
neutrino data, which is we believe free from the above objections.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:28:26 GMT"
},
{
"version": "v2",
"created": "Thu, 25 Oct 2007 18:19:11 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Sturrock",
"P. A.",
""
],
[
"Wheatland",
"M. S.",
""
]
] |
0706.2193 | Guillermo F. Rubilar | G. F. Rubilar | Linear pre-metric electrodynamics and deduction of the light cone | 73 pages, 8 figures, LaTeX, corresponds to published version | AnnalenPhys.11:717-782,2002 | 10.1002/1521-3889(200211)11:10/11<717::AID-ANDP717>3.0.CO;2-6 | null | gr-qc | null | We formulate a general framework for describing the electromagnetic
properties of spacetime. These properties are encoded in the `constitutive
tensor of the vacuum', a quantity analogous to that used in the description of
material media. We give a generally covariant derivation of the Fresnel
equation describing the local properties of the propagation of electromagnetic
waves for the case of the most general possible linear constitutive tensor. We
also study the particular case in which a light cone structure is induced and
the circumstances under which such a structure emerges. In particular, we will
study the relationship between the dual operators defined by the constitutive
tensor under certain conditions and the existence of a conformal metric.
Closure and symmetry of the constitutive tensor will be found as conditions
which ensure the existence of a conformal metric. We will also see how the
metric components can be explicitly deduced from the constitutive tensor if
these two conditions are met. Finally, we will apply the same method to explore
the consequences of relaxing the condition of symmetry and how this affects the
emergence of the light cone.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:42:25 GMT"
}
] | 2017-09-27T00:00:00 | [
[
"Rubilar",
"G. F.",
""
]
] |
0706.2194 | Yuri Lvov | Yuri V. Lvov and Naoto Yokoyama | Nonlinear wave-wave interactions in stratified flows: Direct numerical
simulations | null | Physica D: Nonlinear Phenomena 238, 803-815 (2009) | 10.1016/j.physd.2009.01.016 | null | physics.flu-dyn physics.ao-ph | null | To investigate the formation mechanism of energy spectra of internal waves in
the oceans, direct numerical simulations are performed. The simulations are
based on the reduced dynamical equations of rotating stratified turbulence. In
the reduced dynamical equations only wave modes are retained, and vortices and
horizontally uniform vertical shears are excluded. Despite the simplifications,
our simulations reproduce some key features of oceanic internal-wave spectra:
accumulation of energy at near-inertial waves and realistic frequency and
horizontal wavenumber dependencies. Furthermore, we provide evidence that
formation of the energy spectra in the inertial subrange is dominated by
scale-separated interactions with the near-inertial waves. These findings
support oceanographers' intuition that spectral energy density of internal
waves is the result of predominantly wave-wave interactions.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:43:49 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Dec 2007 20:25:12 GMT"
},
{
"version": "v3",
"created": "Wed, 23 Apr 2008 02:43:00 GMT"
}
] | 2020-06-10T00:00:00 | [
[
"Lvov",
"Yuri V.",
""
],
[
"Yokoyama",
"Naoto",
""
]
] |
0706.2195 | Igor Strakovsky | R.A. Arndt, W.J. Briscoe, I.I. Strakovsky, R.L. Workman (GWU) | Updated analysis of NN elastic scattering to 3 GeV | 16 pages, 14 figures, 2 tables; Fig 10 error corrected; Accepted for
publication in Physical Review C | Phys.Rev.C76:025209,2007 | 10.1103/PhysRevC.76.025209 | null | nucl-th | null | A partial-wave analysis of NN elastic scattering data has been updated to
include a number of recent measurements. Experiments carried out at the Cooler
Synchrotron (COSY) by the EDDA Collaboration have had a significant impact
above 1 GeV. Results are discussed in terms of the partial-wave and
direct-reconstruction amplitudes.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 20:50:55 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 17:32:59 GMT"
},
{
"version": "v3",
"created": "Thu, 19 Jul 2007 19:02:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Arndt",
"R. A.",
"",
"GWU"
],
[
"Briscoe",
"W. J.",
"",
"GWU"
],
[
"Strakovsky",
"I. I.",
"",
"GWU"
],
[
"Workman",
"R. L.",
"",
"GWU"
]
] |
0706.2196 | Henrik Strohmayer | Henrik Strohmayer | Operads of compatible structures and weighted partitions | 16 pages, main result about Koszulness generalized to a large class
of compatible structures | J. Pure Appl. Algebra 212 (2008), no. 11, 2522--2534. | 10.1016/j.jpaa.2008.04.009 | null | math.AT math.CO | null | In this paper we describe operads encoding two different kinds of
compatibility of algebraic structures. We show that there exist decompositions
of these in terms of black and white products and we prove that they are Koszul
for a large class of algebraic structures by using the poset method of B.
Vallette. In particular we show that this is true for the operads of compatible
Lie, associative and pre-Lie algebras.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 21:13:16 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 11:55:50 GMT"
}
] | 2008-09-24T00:00:00 | [
[
"Strohmayer",
"Henrik",
""
]
] |
0706.2197 | Francesco Calura | Francesco Calura (1), Antonio Pipino (2,3), Francesca Matteucci (1,2)
(- 1 INAF - Osservatorio Astronomico di Trieste; 2 Dip. di Astronomia,
Universita' di Trieste; 3 Department of Physics, University of Oxford.) | The cycle of interstellar dust in galaxies of different morphological
types | 20 pages, A&A, accepted. Minor changes after referee report | null | 10.1051/0004-6361:20078090 | null | astro-ph | null | By means of chemical evolution models for galaxies of different morphological
type, we have performed a detailed study of the evolution of the cosmic dust
properties in different environments: the solar neighbourhood, elliptical
galaxies and dwarf irregular galaxies. Starting from the same formalism as
developed by Dwek (1998), We have taken into account dust production from low
and intermediate mass stars, supernovae II and Ia as well as dust destruction
and dust accretion processes in a detailed model of chemical evolution for the
solar vicinity. Then, by means of the same dust prescriptions but adopting
different galactic models (different star formation histories and presence of
galactic winds), we have extended our study to ellipticals and dwarf irregular
galaxies. We have investigated how the assumption of different star formation
histories affects the dust production rates, the dust depletion, the dust
accretion and destruction rates. We have shown how the inclusion of the dust
treatment is helpful in solving the so-called Fe discrepancy, observed in the
hot gaseous halos of local ellipticals, and in reproducing the chemical
abundances observed in the Lyman Break Galaxies. Finally, our new models can be
very useful in future detailed spectro-photometric studies of galaxies.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 21:41:13 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Oct 2007 10:04:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Calura",
"Francesco",
""
],
[
"Pipino",
"Antonio",
""
],
[
"Matteucci",
"Francesca",
""
]
] |
0706.2198 | Mark Henle | Mark L. Henle, R. McGorty, A. D. Dinsmore, and Alex J. Levine | The effect of curvature and topology on membrane hydrodynamics | 4 pages, 3 figures | null | 10.1209/0295-5075/84/48001 | null | cond-mat.soft | null | We study the mobility of extended objects (rods) on a spherical liquid-liquid
interface to show how this quantity is modified in a striking manner by both
the curvature and the topology of the interface. We present theoretical
calculations and experimental measurements of the interfacial fluid velocity
field around a moving rod bound to the crowded interface of a water-in-oil
droplet. By using different droplet sizes, membrane viscosities, and rod
lengths, we show that the viscosity mismatch between the interior and exterior
fluids leads to a suppression of the fluid flow on small droplets that cannot
be captured by the flat interface predictions.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 22:13:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Henle",
"Mark L.",
""
],
[
"McGorty",
"R.",
""
],
[
"Dinsmore",
"A. D.",
""
],
[
"Levine",
"Alex J.",
""
]
] |
0706.2199 | Nicola A. Spaldin | J. M. Rondinelli, M. Stengel and N. A. Spaldin | Carrier-mediated magnetoelectricity in complex oxide heterostructures | null | Nature Nanotechnology 3, 46 - 50 (2008) | 10.1038/nnano.2007.412 | null | cond-mat.mtrl-sci | null | While tremendous success has been achieved to date in creating both single
phase and composite magnetoelectric materials, the quintessential
electric-field control of magnetism remains elusive. In this work, we
demonstrate a linear magnetoelectric effect which arises from a novel
carrier-mediated mechanism, and is a universal feature of the interface between
a dielectric and a spin-polarized metal. Using first-principles density
functional calculations, we illustrate this effect at the SrRuO$_3$/SrTiO$_3$
interface and describe its origin. To formally quantify the magnetic response
of such an interface to an applied electric field, we introduce and define the
concept of spin capacitance. In addition to its magnetoelectric and spin
capacitive behavior, the interface displays a spatial coexistence of magnetism
and dielectric polarization suggesting a route to a new type of interfacial
multiferroic.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 22:14:37 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Rondinelli",
"J. M.",
""
],
[
"Stengel",
"M.",
""
],
[
"Spaldin",
"N. A.",
""
]
] |
0706.2200 | Shih-Chieh Hsu | Shih-Chieh Hsu (for the CDF Collaboration) | Searching for H->WW(*) and Other Diboson Final States at CDF | 4 pages, 5 figures, to appear in the proceedings of 42nd Rencontres
de Moriond on Electroweak Interactions and Unified Theories, La Thuile,
Italy, March 10-17, 2007 | null | null | FERMILAB-CONF-07-156-E | hep-ex | null | We report searches for standard model (SM) Higgs production decaying to WW(*)
and continuum ZZ production in the two charged lepton and two neutrino final
states. The data were collected with the CDF II detector at the Fermilab
Tevatron and correspond to an integrated luminosity of 1.1^fb-1. In order to
separate the processes contributing to the final state, event probabilities
calculated using the leading order differential cross-sections were used to
construct a likelihood ratio discriminant. The observed (median expected) 95%
C.L. upper limit for sigma(H->WW^(*)) with 160 GeV/c^2 mass hypothesis is 1.3
(1.8) pb which corresponds to 3.4 (4.8) times the SM prediction at
next-to-next-to-leading logarithmic level (NNLL) calculation. The significance
of the observed ZZ signal is 1.9 sigma and the 95% C.L. upper limit is 3.4 pb
which is consistent with the next-to-leading order (NLO) calculation of
1.4+/-0.1 pb.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 22:36:31 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Hsu",
"Shih-Chieh",
"",
"for the CDF Collaboration"
]
] |
0706.2201 | Diogo Soares-Pinto | D. O. Soares-Pinto, M. S. Reis, R. S. Sarthour, I. S. Oliveira | Spin-waves in a complex magnetic system: nonextensive approach | 9 pages, 1 figure | J. Stat. Mech. (2007) P08011 | 10.1088/1742-5468/2007/08/P08011 | null | cond-mat.stat-mech | null | In this paper we analyze the spin-wave excitations (magnons) of an
inhomogeneous spin system within the Boltzmann-Gibbs framework and then connect
the results with the nonextensive approach (in the sense of Tsallis
statistics). Considering an equivalence between those two frameworks, we could
connect the entropic parameter q with moments of the distribution of exchange
integrals of the inhomogenous system. It ratifies the idea that the entropic
parameter is connected to the microscopic properties of the system.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:02:49 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 15:26:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Soares-Pinto",
"D. O.",
""
],
[
"Reis",
"M. S.",
""
],
[
"Sarthour",
"R. S.",
""
],
[
"Oliveira",
"I. S.",
""
]
] |
0706.2202 | Graeme Milton | Graeme W. Milton | New metamaterials with macroscopic behavior outside that of continuum
elastodynamics | 14 pages, 4 figures | null | 10.1088/1367-2630/9/10/359 | null | math-ph math.MP | null | Metamaterials are constructed such that, for a narrow range of frequencies,
the momentum density depends on the local displacement gradient, and the stress
depends on the local velocity. In these models the momentum density generally
depends not only on the strain, but also on the local rotation, and the stress
is generally not symmetric. A variant is constructed for which, at a fixed
frequency, the momentum density is independent of the local rotation (but still
depends on the strain) and the stress is symmetric (but still depends on the
velocity). Generalizations of these metamaterials may be useful in the design
of elastic cloaking devices.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:06:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Milton",
"Graeme W.",
""
]
] |
0706.2203 | Etele Molnar | A. Dumitru, E. Molnar and Y. Nara | Entropy production in high-energy heavy-ion collisions and the
correlation of shear viscosity and thermalization time | 10 pages, 10 figures, Text updated, references added, two new figures
added, normalization in Fig.1 corrected, final version to be published in PRC | Phys.Rev.C76:024910,2007 | 10.1103/PhysRevC.76.024910 | null | nucl-th hep-ph hep-th nucl-ex | null | We study entropy production in the early stage of high-energy heavy-ion
collisions due to shear viscosity. We employ the second-order theory of
Israel-Stewart with two different stress relaxation times, as appropriate for
strong coupling or for a Boltzmann gas, respectively, and compare the
hydrodynamic evolution. Based on present knowledge of initial particle
production, we argue that entropy production is tightly constrained. We derive
new limits on the shear viscosity to entropy density ratio $\eta/s$,
independent from elliptic flow effects, and determine the corresponding
Reynolds number. Furthermore, we show that for a given entropy production
bound, that the initial time $\tau_0$ for hydrodynamics is correlated to the
viscosity. The conjectured lower bound for $\eta/s$ provides a lower limit for
$\tau_0$.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:11:24 GMT"
},
{
"version": "v2",
"created": "Fri, 10 Aug 2007 13:33:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dumitru",
"A.",
""
],
[
"Molnar",
"E.",
""
],
[
"Nara",
"Y.",
""
]
] |
0706.2204 | Nicolae Manolache | Nicolae Manolache | Gorenstein Multiple Structures on Smooth Algebraic Varieties | null | null | null | null | math.AG math.AC | null | We characterize the Gorenstein nilpotent scheme structures on a smooth
algebraic variety as support, in terms of a duality property of the graded
objects associated to two canonical filtrations.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:15:09 GMT"
}
] | 2007-06-18T00:00:00 | [
[
"Manolache",
"Nicolae",
""
]
] |
0706.2205 | Genaro Toledo | G. Toledo Sanchez, J. L. Garcia-Luna and V. Gonzalez-Enciso | Role of resonances in rho^0 -> pi^+ pi^- gamma | 5 pages, 5 figures, accepted for publication in PRD | Phys.Rev.D76:033001,2007 | 10.1103/PhysRevD.76.033001 | null | hep-ph | null | We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0
-> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are
driven by the mass and width parameters of the sigma(600), and the usually
neglected contribution of the a_1(1260), although small by itself, may become
sizable through its interference with pion bremsstrahlung, and the proper
relative sign can favor the central value of the experimental branching ratio.
We present a procedure, using the gauge invariant structure of the resonant
amplitudes, to kinematically enhance the resonant effects in the angular and
energy distribution of the photon. We also elaborate on the coupling constants
involved.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:16:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sanchez",
"G. Toledo",
""
],
[
"Garcia-Luna",
"J. L.",
""
],
[
"Gonzalez-Enciso",
"V.",
""
]
] |
0706.2206 | Jonathan Swift | J. Swift and Wm. J. Welch | A Case Study of Low-Mass Star Formation | 24 pages, 21 figures, ApJS accepted | null | 10.1086/520846 | null | astro-ph | null | This article synthesizes observational data from an extensive program aimed
toward a comprehensive understanding of star formation in a low-mass
star-forming molecular cloud. New observations and published data spanning from
the centimeter wave band to the near infrared reveal the high and low density
molecular gas, dust, and pre-main sequence stars in L1551.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:43:00 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Swift",
"J.",
""
],
[
"Welch",
"Wm. J.",
""
]
] |
0706.2207 | Hongwei Yu | Hongwei Yu and Wenting Zhou | Relationship between Hawking radiation from black holes and spontaneous
excitation of atoms | 9 pages, no figures, typos corrected in the references, published
version | Phys.Rev.D76:027503,2007 | 10.1103/PhysRevD.76.027503 | null | hep-th gr-qc | null | Using the formalism that separates the contributions of vacuum fluctuations
and radiation reaction to the rate of change of the mean atomic energy, we show
that a two-level atom in interaction with a quantum massless scalar field both
in the Hartle-Hawking and Unruh vacuum in a 1+1 dimensional black hole
background spontaneously excites as if there is thermal radiation at the
Hawking temperature emanating from the black hole. Our calculation, therefore,
ties the existence of Hawking radiation to the spontaneous excitation of a
two-level atom placed in vacuum in the exterior of a black hole and shows
pleasing consistence of two different physical phenomena, the Hawking radiation
and the spontaneous excitation of atoms, which are quite prominent in their own
right.
| [
{
"version": "v1",
"created": "Thu, 14 Jun 2007 23:58:32 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 00:06:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yu",
"Hongwei",
""
],
[
"Zhou",
"Wenting",
""
]
] |
0706.2208 | Francisco Jose Herranz | Angel Ballesteros, Francisco J. Herranz, Orlando Ragnisco and Mariano
Santander | Contractions, deformations and curvature | 17 pages. Based on the talk given in the Oberwolfach workshop:
Deformations and Contractions in Mathematics and Physics (Germany, january
2006) organized by M. de Montigny, A. Fialowski, S. Novikov and M.
Schlichenmaier | Int. J. Theor. Phys. 47 (2008) 649-663 | 10.1007/s10773-007-9489-9 | null | math-ph math.MP math.QA | null | The role of curvature in relation with Lie algebra contractions of the
pseudo-ortogonal algebras so(p,q) is fully described by considering some
associated symmetrical homogeneous spaces of constant curvature within a
Cayley-Klein framework. We show that a given Lie algebra contraction can be
interpreted geometrically as the zero-curvature limit of some underlying
homogeneous space with constant curvature. In particular, we study in detail
the contraction process for the three classical Riemannian spaces (spherical,
Euclidean, hyperbolic), three non-relativistic (Newtonian) spacetimes and three
relativistic ((anti-)de Sitter and Minkowskian) spacetimes. Next, from a
different perspective, we make use of quantum deformations of Lie algebras in
order to construct a family of spaces of non-constant curvature that can be
interpreted as deformations of the above nine spaces. In this framework, the
quantum deformation parameter is identified as the parameter that controls the
curvature of such "quantum" spaces.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 00:27:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ballesteros",
"Angel",
""
],
[
"Herranz",
"Francisco J.",
""
],
[
"Ragnisco",
"Orlando",
""
],
[
"Santander",
"Mariano",
""
]
] |
0706.2209 | Scott Chapman | Scott Chapman | SU(3) Ghosts with Spin | null | null | null | null | hep-th | null | A new Lorentz-covariant gauge is presented for SU(3). In this gauge, both the
ghosts and the gauge fields in the (4, 5, 6, 7) gauge directions acquire
half-integral spin. As a result, the ghosts in these directions have the
correct relationship between spin and statistics, while the gauge fields have
the incorrect relationship. Consequently, asymptotic ghost states are not
forbidden in this gauge and can possibly form new matter states. Conversely,
asymptotic gauge fields in the (4, 5, 6, 7) directions are forbidden in this
gauge, so the SU(3) symmetry is broken down to an SU(2)xU(1) symmetry
asymptotically.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 00:29:51 GMT"
}
] | 2007-06-18T00:00:00 | [
[
"Chapman",
"Scott",
""
]
] |
0706.2210 | Cecilia Lunardini | Wick Haxton and Cecilia Lunardini | A Mathematica script for harmonic oscillator nuclear matrix elements
arising in semileptonic electroweak interactions | 15 pages, 2 tables, Mathematica notebook included in the form of
figures. Mathematica package and documentation available at
http://www.int.washington.edu/users/lunardi/7o.htm. Replaced version has
improved graphics; text unchanged | null | 10.1016/j.cpc.2008.02.018 | INT PUB 07-15 | nucl-th | null | Semi-leptonic electroweak interactions in nuclei - such as \beta decay, \mu
capture, charged- and neutral-current neutrino reactions, and electron
scattering - are described by a set of multipole operators carrying definite
parity and angular momentum, obtained by projection from the underlying nuclear
charge and three-current operators. If these nuclear operators are approximated
by their one-body forms and expanded in the nucleon velocity through order
|\vec{p}|/M, where \vec{p} and M are the nucleon momentum and mass, a set of
seven multipole operators is obtained. Nuclear structure calculations are often
performed in a basis of Slater determinants formed from harmonic oscillator
orbitals, a choice that allows translational invariance to be preserved.
Harmonic-oscillator single-particle matrix elements of the multipole operators
can be evaluated analytically and expressed in terms of finite polynomials in
q^2, where q is the magnitude of the three-momentum transfer. While results for
such matrix elements are available in tabular form, with certain restriction on
quantum numbers, the task of determining the analytic form of a response
function can still be quite tedious, requiring the folding of the tabulated
matrix elements with the nuclear density matrix, and subsequent algebra to
evaluate products of operators. Here we provide a Mathematica script for
generating these matrix elements, which will allow users to carry out all such
calculations by symbolic manipulation. This will eliminate the errors that may
accompany hand calculations and speed the calculation of electroweak nuclear
cross sections and rates. We illustrate the use of the new script by
calculating the cross sections for charged- and neutral-current neutrino
scattering in ^{12}C.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 00:34:16 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jun 2007 19:02:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Haxton",
"Wick",
""
],
[
"Lunardini",
"Cecilia",
""
]
] |
0706.2211 | Wen Zhao | Wen Zhao | Holographic hessence models | 10 pages, 5 figures, PLB accepted | Phys.Lett.B655:97-103,2007 | 10.1016/j.physletb.2007.08.083 | Phys.Lett.B 655 (2007) 97-103 | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the evolution of holographic hessence model, which satisfies the
holographic principle and can naturally realizes the equation of state crossing
-1. By discussing the evolution of the models in the $w w'$ plane, we find
that, if $c\geq1$, $w_{he}\geq-1$ and $\dot{V}<0$ keep for all time, which are
quintessence-like. However, if $c<-1$, which mildly favors the current
observations, $w_{he}$ evolves from $w_{he}>-1$ to $w_{he}<-1$, and the
potential is a nonmonotonic function. In the earlier time, the potential must
be rolled down, and then be climbed up. Considered the current constraint on
the parameter $c$, we reconstruct the potential of the holographic hessence
model.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 00:34:31 GMT"
},
{
"version": "v2",
"created": "Fri, 31 Aug 2007 12:13:25 GMT"
},
{
"version": "v3",
"created": "Sat, 4 Oct 2008 09:25:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Zhao",
"Wen",
""
]
] |
0706.2212 | Paulo Arratia | P.E. Arratia, J.P. Gollub | Predicting the progress of diffusively limited chemical reactions in the
presence of chaotic advection | 4 pages, 4 figures, updated references | Phys. Rev. Lett. 96, 024501 (2006) | 10.1103/PhysRevLett.96.024501 | null | physics.flu-dyn physics.chem-ph | null | The effects of chaotic advection and diffusion on fast chemical reactions in
two-dimensional fluid flows are investigated using experimentally measured
stretching fields and fluorescent monitoring of the local concentration. Flow
symmetry, Reynolds number, and mean path length affect the spatial distribution
and time dependence of the reaction product. A single parameter \lambda*N,
where \lambda is the mean Lyapunov exponent and N is the number of mixing
cycles, can be used to predict the time-dependent total product for flows
having different dynamical features.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 19:53:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Arratia",
"P. E.",
""
],
[
"Gollub",
"J. P.",
""
]
] |
0706.2213 | Vu Huynh | J\'er\^ome Dubois, Vu Huynh and Yoshikazu Yamaguchi | Non-abelian Reidemeister torsion for twist knots | 36 pages and 4 figures. Title and Abstract are modified. typos and
inconsistent notations corrected. minor changes. to appear in Journal of Knot
Theory and Its Ramifications | null | null | null | math.GT | null | This paper gives an explicit formula for the SL_2(C)-non-abelian Reidemeister
torsion as defined in [Dub06] in the case of twist knots. For hyperbolic twist
knots, we also prove that the non-abelian Reidemeister torsion at the holonomy
representation can be expressed as a rational function evaluated at the cusp
shape of the knot.
| [
{
"version": "v1",
"created": "Fri, 15 Jun 2007 01:42:23 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jul 2007 02:40:33 GMT"
},
{
"version": "v3",
"created": "Sun, 9 Mar 2008 08:58:46 GMT"
}
] | 2008-03-09T00:00:00 | [
[
"Dubois",
"Jérôme",
""
],
[
"Huynh",
"Vu",
""
],
[
"Yamaguchi",
"Yoshikazu",
""
]
] |
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