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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.3814 | Bruno Henriques | Bruno Henriques, Serena Bertone, Peter Thomas | The effect of dwarf galaxies disruption in semi-analytic models | 7 pages, 6 figures, accepted for publication in MNRAS, 2 figures
changed and references added | null | 10.1111/j.1365-2966.2007.12684.x | null | astro-ph | null | We present results for a galaxy formation model that includes a simple
treatment for the disruption of dwarf galaxies by gravitational forces and
galaxy encounters within galaxy clusters. This is implemented a posteriori in a
semi-analytic model by considering the stability of cluster dark matter
sub-haloes at z=0. We assume that a galaxy whose dark matter substructure has
been disrupted will itself disperse, while its stars become part of the
population of intracluster stars responsible for the observed intracluster
light. Despite the simplicity of this assumption, our results show a
substantial improvement over previous models and indicate that the inclusion of
galaxy disruption is indeed a necessary ingredient of galaxy formation models.
We find that galaxy disruption suppresses the number density of dwarf galaxies
by about a factor of two. This makes the slope of the faint end of the galaxy
luminosity function shallower, in agreement with observations. In particular,
the abundance of faint, red galaxies is strongly suppressed. As a result, the
luminosity function of red galaxies and the distinction between the red and the
blue galaxy populations in colour-magnitude relationships are correctly
predicted. Finally, we estimate a fraction of intracluster light comparable to
that found in clusters of galaxies.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 19:17:18 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Nov 2007 16:28:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Henriques",
"Bruno",
""
],
[
"Bertone",
"Serena",
""
],
[
"Thomas",
"Peter",
""
]
] |
0706.3815 | Szymon Plewik | Andrzej Kucharski and Szymon Plewik | Inverse Systems and I-Favorable Spaces | 13 pages | null | null | null | math.GN math.LO | null | A compact space X is I-favorable if, and only if X can be representing as a
limit of $\sigma$-complete inverse system of compact metrizable spaces with
skeletal bonding maps.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 12:39:23 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Mar 2008 11:41:16 GMT"
}
] | 2008-03-03T00:00:00 | [
[
"Kucharski",
"Andrzej",
""
],
[
"Plewik",
"Szymon",
""
]
] |
0706.3816 | Alekos Vidras | Lev Aizenberg, Alekos Vidras | Geometric generalizations in Kresin-Maz'ya Sharp Real-Part Theorems | 9 pages | null | null | null | math.CV | null | In the present article we give geometric generalizations of the estimates
from Chapters 5,6,7 from \cite{krem:gnus}, while extending their sharpness to
new cases.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 12:42:50 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Aizenberg",
"Lev",
""
],
[
"Vidras",
"Alekos",
""
]
] |
0706.3817 | Karl-Georg Schlesinger | Karl-Georg Schlesinger | Some remarks on mirror symmmetry and noncommutative elliptic curves | 16 pages | null | null | null | hep-th | null | This paper agrees basically with the talk of the author at the workshop
"Homological Mirror Symmetry and Applications", Institute for Advanced Study,
Princeton, March 2007.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 12:46:47 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Schlesinger",
"Karl-Georg",
""
]
] |
0706.3818 | Karlheinz Gr\"ochenig | Karlheinz Gr\"ochenig, Richard F. Bass | Random Sampling of Entire Functions of Exponential Type in Several
Variables | 22 pages Revised the section on covering numbers and clarified some
estimates. Added two references | Israel J. Math. 177 (2010), 1 -- 28 | null | null | math.PR math.FA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the problem of random sampling for band-limited functions. When
can a band-limited function $f$ be recovered from randomly chosen samples
$f(x_j), j\in \mathbb{N}$? We estimate the probability that a sampling
inequality of the form
A\|f\|_2^2 \leq \sum_{j\in \mathbb{N}} |f(x_j)|^2 \leq B \|f\|_2^2 hold
uniformly all functions $f\in L^2(\mathbb{R}^d)$ with supp $\hat{f} \subseteq
[-1/2,1/2]^d$ or some subset of \bdl functions. In contrast to discrete models,
the space of band-limited functions is infinite-dimensional and its functions
"live" on the unbounded set $\mathbb{R}^d$. This fact raises new problems and
leads to both negative and positive results. (a) With probability one, the
sampling inequality fails for any reasonable definition of a random set on
$\mathbb{R}^d$, e.g., for spatial Poisson processes or uniform distribution
over disjoint cubes. (b) With overwhelming probability, the sampling inequality
holds for certain compact subsets of the space of band-limited functions and
for sufficiently large sampling size.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 12:57:20 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jun 2008 09:41:30 GMT"
}
] | 2011-04-27T00:00:00 | [
[
"Gröchenig",
"Karlheinz",
""
],
[
"Bass",
"Richard F.",
""
]
] |
0706.3819 | Luca Salasnich | Luca Salasnich (CNR-INFM and CNISM, Univ. Padova) | Condensate Fraction of a Two-Dimensional Attractive Fermi Gas | 4 pages, 2 figures, accepted for publication in Phys. Rev. A | Phys. Rev. A 76, 015601 (2007) | 10.1103/PhysRevA.76.015601 | null | cond-mat.stat-mech cond-mat.supr-con | null | We investigate the Bose-Einstein condensation of fermionic pairs in a
two-dimensional uniform two-component Fermi superfluid obtaining an explicit
formula for the condensate density as a function of the chemical potential and
the energy gap. By using the mean-field extended BCS theory, we analyze, as a
function of the bound-state energy, the off-diagonal long-range order in the
crossover from the Bardeen-Cooper-Schrieffer (BCS) state of weakly-bound Cooper
pairs to the Bose-Einstein Condensate (BEC) of strongly-bound molecular dimers.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 12:50:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Salasnich",
"Luca",
"",
"CNR-INFM and CNISM, Univ. Padova"
]
] |
0706.3820 | Yu-Gang Ma | S. Zhang, G. L. Ma, Y. G. Ma, X. Z. Cai, J. H. Chen, H. Z. Huang, W.
Q. Shen, X. H. Shi, F. Jin, J. Tian, C. Zhong, and J. X. Zuo | Transverse momentum and pseudorapidity dependences of $'\bm{Mach-like}'$
correlations for central Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV | 6 pages, 6 figures; accepted by Phys. Rev. C | Phys.Rev.C76:014904,2007 | 10.1103/PhysRevC.76.014904 | null | nucl-th hep-ph nucl-ex | null | The transverse momentum and pseudorapidity dependences of partonic
{`\it{Mach-like}'} shock wave have been studied by using a multi-phase
transport model (AMPT) with both partonic and hadronic interactions. The
splitting parameter $D$, i.e. half distance between two splitting peaks on away
side in di-hadron azimuthal angular ($\Delta\phi$) correlations, slightly
increases with the transverse momentum of associated hadrons ($p^{assoc}_T$),
which is consistent with preliminary experimental trend, owing to different
interaction-lengths/numbers between wave partons and medium in strong parton
cascade. On the other hand, the splitting parameter $D$ as a function of
pseudorapidity of associated hadrons ($\eta^{assoc}$), keeps flat in
mid-pseudorapidity region and rapidly drops in high-pseudorapidity region,
which is as a result of different violent degrees of jet-medium interactions in
the medium that has different energy densities in the longitudinal direction.
It is proposed that the research on the properties of {`\it{Mach-like}'}
correlation can shed light on the knowledge of both partonic and hadronic
interactions at RHIC.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 12:55:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Zhang",
"S.",
""
],
[
"Ma",
"G. L.",
""
],
[
"Ma",
"Y. G.",
""
],
[
"Cai",
"X. Z.",
""
],
[
"Chen",
"J. H.",
""
],
[
"Huang",
"H. Z.",
""
],
[
"Shen",
"W. Q.",
""
],
[
"Shi",
"X. H.",
""
],
[
"Jin",
"F.",
""
],
[
"Tian",
"J.",
""
],
[
"Zhong",
"C.",
""
],
[
"Zuo",
"J. X.",
""
]
] |
0706.3821 | Jason Twamley | C. Facer, J. Twamley and J. D. Cresser | Quantum switching networks for perfect qubit routing | null | null | 10.1103/PhysRevA.77.012334 | null | quant-ph | null | We develop the work of Christandl et al. [M. Christandl, N. Datta, T. C.
Dorlas, A. Ekert, A. Kay, and A. J. Landahl, Phys. Rev. A 71, 032312 (2005)],
to show how a d-hypercube homogenous network can be dressed by additional links
to perfectly route quantum information between any given input and output nodes
in a duration which is independent of the routing chosen and, surprisingly,
size of the network.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:11:14 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Facer",
"C.",
""
],
[
"Twamley",
"J.",
""
],
[
"Cresser",
"J. D.",
""
]
] |
0706.3822 | Thomas Kernreiter | A. Bartl, K. Hohenwarter-Sodek, T. Kernreiter, O. Kittel | CP asymmetries with Longitudinal and Transverse Beam Polarizations in
Neutralino Production and Decay into the Z^0 Boson at the ILC | 25pp; minor changes, published version | JHEP 0709:079,2007 | 10.1088/1126-6708/2007/09/079 | null | hep-ph | null | We study neutralino production at the linear collider with the subsequent
two-body decays ~chi^0_i -> ~chi^0_n Z^0 and Z^0 -> l^+ l^-, with l=e, mu, tau,
or Z^0 -> q q- with q=c,b. We show that transverse electron and positron beam
polarizations allow the definition of unique CP observables. These are
azimuthal asymmetries in the distributions of the final leptons or quarks. We
calculate these CP asymmetries and the cross sections in the Minimal
Supersymmetric Standard Model with complex higgsino and gaugino parameters mu
and M_1. For final quark pairs, we find CP asymmetries as large as 30%. We
discuss the significances for observing the CP asymmetries at the International
Linear Collider (ILC). Finally we compare the CP asymmetries with those
asymmetries which require unpolarized and/or longitudinally polarized beams
only.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:17:07 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Sep 2007 09:11:20 GMT"
}
] | 2009-01-06T00:00:00 | [
[
"Bartl",
"A.",
""
],
[
"Hohenwarter-Sodek",
"K.",
""
],
[
"Kernreiter",
"T.",
""
],
[
"Kittel",
"O.",
""
]
] |
0706.3823 | Simone Calogero | Simone Calogero, J. Mark Heinzle | Dynamics of Bianchi type I elastic spacetimes | 28 pages, 11 figures | Class.Quant.Grav.24:5173-5200,2007 | 10.1088/0264-9381/24/20/016 | null | gr-qc | null | We study the global dynamical behavior of spatially homogeneous solutions of
the Einstein equations in Bianchi type I symmetry, where we use non-tilted
elastic matter as an anisotropic matter model that naturally generalizes
perfect fluids. Based on our dynamical systems formulation of the equations we
are able to prove that (i) toward the future all solutions isotropize; (ii)
toward the initial singularity all solutions display oscillatory behavior;
solutions do not converge to Kasner solutions but oscillate between different
Kasner states. This behavior is associated with energy condition violation as
the singularity is approached.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:15:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Calogero",
"Simone",
""
],
[
"Heinzle",
"J. Mark",
""
]
] |
0706.3824 | Markus Kasper | Markus Kasper (ESO), Beth A. Biller (Steward Observatory), Adam
Burrows (Steward Observatory), Wolfgang Brandner (MPIA), Jano Budaj (Steward
Observatory) and Laird M. Close (Steward Observatory) | The very nearby M/T dwarf binary SCR 1845-6357 | 5 pages, 4 figures, accepted for publication in Astronomy &
Astrophysics | null | 10.1051/0004-6361:20077881 | null | astro-ph | null | The recently discovered star SCR 1845-6357 is the first late M/T dwarf binary
discovered. SCR 1845 is a particular object due to its tight orbit (currently
around 4 AU) and its proximity to the Sun (3.85 pc). We present spatially
resolved VLT/NACO images and low resolution spectra of SCR 1845 in the J, H and
K near-infrared bands. Since the T dwarf companion, SCR 1845B, is so close to
the primary SCR 1845A, orbital motion is evident even within a year. Following
the orbital motion, the binary's mass can be measured accurately within a
decade, making SCR 1845B a key T-dwarf mass-luminosity calibrator. The NIR
spectra allow for accurate determination of spectral type and also for rough
estimates of the object's physical parameters. The spectral type of SCR 1845B
is determined by direct comparison of the flux calibrated JHK spectra with T
dwarf standard template spectra and also by NIR spectral indices obtained from
synthetic photometry. Constrained values for surface gravity, effective
temperature and metallicity are derived by comparison with model spectra. Our
data prove that SCR 1845B is a brown dwarf of spectral type T6 that is
co-moving with and therefore gravitationally bound to the M8.5 primary. Fitting
the NIR spectrum of SCR 1845B to model spectra yields an effective temperature
of about 950K and a surface gravity log(g)=5.1 (cgs) assuming solar
metallicity. Mass and age of SCR 1845B are in the range 40 to 50 Jupiter masses
and 1.8 to 3.1 Gyr.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:18:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kasper",
"Markus",
"",
"ESO"
],
[
"Biller",
"Beth A.",
"",
"Steward Observatory"
],
[
"Burrows",
"Adam",
"",
"Steward Observatory"
],
[
"Brandner",
"Wolfgang",
"",
"MPIA"
],
[
"Budaj",
"Jano",
"",
"Steward\n Observatory"
],
[
"Close",
"Laird M.",
"",
"Steward Observatory"
]
] |
0706.3825 | Bruno Lombard | Bruno Lombard (LMA), Jo\"el Piraux (LMA), C\'eline G\'elis (GA), Jean
Virieux (GA) | Free and smooth boundaries in 2-D finite-difference schemes for
transient elastic waves | accepted and to be published in Geophys. J. Int | Geophysical Journal International 172 (2008) 252-261 | 10.1111/j.1365-246X.2007.03620.x | null | physics.class-ph physics.geo-ph | null | A method is proposed for accurately describing arbitrary-shaped free
boundaries in single-grid finite-difference schemes for elastodynamics, in a
time-domain velocity-stress framework. The basic idea is as follows: fictitious
values of the solution are built in vacuum, and injected into the numerical
integration scheme near boundaries. The most original feature of this method is
the way in which these fictitious values are calculated. They are based on
boundary conditions and compatibility conditions satisfied by the successive
spatial derivatives of the solution, up to a given order that depends on the
spatial accuracy of the integration scheme adopted. Since the work is mostly
done during the preprocessing step, the extra computational cost is negligible.
Stress-free conditions can be designed at any arbitrary order without any
numerical instability, as numerically checked. Using 10 grid nodes per minimal
S-wavelength with a propagation distance of 50 wavelengths yields highly
accurate results. With 5 grid nodes per minimal S-wavelength, the solution is
less accurate but still acceptable. A subcell resolution of the boundary inside
the Cartesian meshing is obtained, and the spurious diffractions induced by
staircase descriptions of boundaries are avoided. Contrary to what occurs with
the vacuum method, the quality of the numerical solution obtained with this
method is almost independent of the angle between the free boundary and the
Cartesian meshing.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:21:01 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Sep 2007 08:42:46 GMT"
}
] | 2007-12-17T00:00:00 | [
[
"Lombard",
"Bruno",
"",
"LMA"
],
[
"Piraux",
"Joël",
"",
"LMA"
],
[
"Gélis",
"Céline",
"",
"GA"
],
[
"Virieux",
"Jean",
"",
"GA"
]
] |
0706.3826 | H\'ector Ot\'i-Floranes | H. Oti-Floranes and J. M. Mas-Hesse | Calibration of Star Formation Rate Tracers with Population Synthesis
Models: the X-ray to FIR Luminosities Ratio | 2 pages, 4 EPS figures, uses asp2006.sty, to be published in the
proceedings of the workshop 'Pathways through an eclectic Universe', J. H.
Knapen, T. J. Mahoney, and A. Vazdekis (Eds.), ASP Conf. Ser., 2007 | null | null | null | astro-ph | null | The study of massive star formation needs some basic tools, among which
reliable SFR tracers are crucial ones. We are presently revising the
calibration of SFR tracers at different wavelength ranges using last generation
evolutionary population synthesis codes. The FIR luminosity produced by the
heated dust in star forming regions is commonly used to characterize a
starburst. The X-ray luminosity has been found to show a narrow correlation
with it, and therefore it has been proposed as an additional tracer of
potential interest for high $z$ galaxies, whose FIR emission is redshifted to
the sub-mm range. In this communication we analyze the evolution of the X-ray
to FIR luminosities ratio as predicted by the CMHK population synthesis models,
both for constant stellar formation and instantaneous bursts. The results are
compared to some sample data taken from the literature. The conclusion drawn
from the comparison is that the empirical calibration of the soft X-ray
luminosity seems a valid SFR tracer only for starbursts around a rather short
period of time.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:26:24 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Oti-Floranes",
"H.",
""
],
[
"Mas-Hesse",
"J. M.",
""
]
] |
0706.3827 | Rui Vilela-Mendes | R. Vilela Mendes | The fractional volatility model: An agent-based interpretation | 23 pages, 11 figures | Physica A: Statistical Mechanics and its Applications, 387 (2008)
3987-3994 | 10.1016/j.physa.2008.01.052 | null | q-fin.ST physics.data-an physics.soc-ph | null | Based on criteria of mathematical simplicity and consistency with empirical
market data, a model with volatility driven by fractional noise has been
constructed which provides a fairly accurate mathematical parametrization of
the data. Here, some features of the model are discussed and, using agent-based
models, one tries to find which agent strategies and (or) properties of the
financial institutions might be responsible for the features of the fractional
volatility model.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:22:11 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 15:05:21 GMT"
}
] | 2010-08-31T00:00:00 | [
[
"Mendes",
"R. Vilela",
""
]
] |
0706.3828 | Nicolas Ressayre | S\'ebastien Jansou (I3M), Nicolas Ressayre (I3M) | Invariant deformations of orbit closures in $\mathfrak{sl}_n$ | 16 pages | null | null | null | math.AG math.RT | null | We study deformations of orbit closures for the action of a connected
semisimple group $G$ on its Lie algebra $\mathfrak{g}$, especially when $G$ is
the special linear group. The tools we use are on the one hand the invariant
Hilbert scheme and on the other hand the sheets of $\mathfrak{g}$. We show that
when $G$ is the special linear group, the connected components of the invariant
Hilbert schemes we get are the geometric quotients of the sheets of
$\mathfrak{g}$. These quotients were constructed by Katsylo for a general
semisimple Lie algebra $\mathfrak{g}$; in our case, they happen to be affine
spaces.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:32:46 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 11:42:01 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Jansou",
"Sébastien",
"",
"I3M"
],
[
"Ressayre",
"Nicolas",
"",
"I3M"
]
] |
0706.3829 | Peter Erwin | Peter Erwin, Michael Pohlen, John E. Beckman, Leonel Gutierrez, and
Rebeca Aladro | The Outer Structure of Galactic Disks: Connections Between Bars, Disks,
and Environments | LaTeX, 4 pages, 2 EPS figures, uses modified newpasp.sty (included).
To appear in Pathways through an Eclectic Universe, eds. J. H. Knapen, T. J.
Mahoney, & A. Vazdekis | null | null | null | astro-ph | null | Surface-brightness profiles for early-type (S0-Sb) disks exhibit three main
classes (Type I, II, and III). Type II profiles are more common in barred
galaxies, and most of the time appear to be related to the bar's Outer Lindblad
Resonance. Roughly half of barred galaxies in the field have Type II profiles,
but almost none in the Virgo Cluster do; this might be related to ram-pressure
stripping in clusters. A strong \textit{anti}correlation is found between Type
III profiles ("antitruncations") and bars: Type III profiles are most common
when there is no bar, and least common when there is a strong bar.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:43:46 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Erwin",
"Peter",
""
],
[
"Pohlen",
"Michael",
""
],
[
"Beckman",
"John E.",
""
],
[
"Gutierrez",
"Leonel",
""
],
[
"Aladro",
"Rebeca",
""
]
] |
0706.3830 | Michael Pohlen | M.Pohlen (1), P. Erwin (2), I. Trujillo (3), and J.E. Beckman (3)
(Kapteyn Astronomical Institute, Groningen, NL (1), Max-Planck-Institut fuer
extraterrestrische Physik, Garching, D (2), Instituto de Astrofisica de
Canarias, La Laguna, E (3)) | Three Types of Galaxy Disks | LaTeX, 4 pages. To appear in: ``Pathways through an eclectic
Universe'', J. H. Knapen, T. J. Mahoney, and A. Vazdekis (Eds.), ASP Conf.
Ser., 2007 | null | null | null | astro-ph | null | We present our new scheme for the classification of radial stellar surface
brightness profiles for disk galaxies. We summarize the current theoretical
attempts to understand their origin and give an example of an application by
comparing local galaxies with their counterparts at high redshift (z~1).
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:44:55 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Pohlen",
"M.",
""
],
[
"Erwin",
"P.",
""
],
[
"Trujillo",
"I.",
""
],
[
"Beckman",
"J. E.",
""
]
] |
0706.3831 | Nicolas Peretto | N. Peretto, G.A. Fuller, A.A. Zijlstra, N.A. Patel | The massive expanding molecular torus in the planetary nebula NGC 6302 | 13 pages, 10 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20066973 | null | astro-ph | null | We measure the mass and kinematics of the massive molecular torus in the
planetary nebula NGC 6302. The nebula is the proto-typical butterfly nebula.
The origin of the wing-like morphology is disputed: determining the mass-loss
history of the confining torus is an important step in understanding the
formation of this structure. We performed submillimeter observations with JCMT
and the SMA interferometer. The continuum emission as well as the J=2-1 and 3-2
transitions of 12CO and 13CO are analysed at arcsecond resolution. The CO
emission indicates a mass of the torus of ~ 2Msun +/- 1Msun. The 12CO and 13CO
emission matches the dark lane seen in absorption in the Halpha image of the
object. The CO torus is expanding with a velocity of ~ 8 km/s, centred at
Vlsr=-31.5 km/s. The size and expansion velocity of the torus indicates that
the torus was ejected from ~ 7500 yr to 2900 yr ago, with a mass-loss rate of
5x10^{-4}Msun/yr. We also see a ballistic component in the CO images with a
velocity gradient of 140 km/s/pc.
The derived mass-loss history of the torus favours binary interaction as the
cause of the ejection of the torus. We predict the existence of a companion
with an orbital period P < 1 month.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:50:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Peretto",
"N.",
""
],
[
"Fuller",
"G. A.",
""
],
[
"Zijlstra",
"A. A.",
""
],
[
"Patel",
"N. A.",
""
]
] |
0706.3832 | Pablo San-Jose | P. San-Jose, E. Prada, D. S. Golubev | Universal scaling of current fluctuations in disordered graphene | 9 pages, 7 figures. Published version, includes corrected figure for
Fano factor | Physical Review B 76, 195445 (2007) | 10.1103/PhysRevB.76.195445 | null | cond-mat.mes-hall cond-mat.dis-nn | null | We analyze the full transport statistics of graphene with smooth disorder at
low dopings. First we consider the case of 1D disorder for which the
transmission probability distribution is given analytically in terms of the
graphene-specific mean free path. All current cumulants are shown to scale with
system parameters (doping, size, disorder strength and correlation length) in
an identical fashion for large enough systems. In the case of 2D disorder,
numerical evidence is given for the same kind of identical scaling of all
current cumulants, so that the ratio of any two such cumulants is universal.
Specific universal values are given for the Fano factor, which is smaller than
the pseudodiffusive value of ballistic graphene (F=1/3) both for 1D (F=0.243)
and 2D (F=0.295) disorder. On the other hand, conductivity in wide samples is
shown to grow without saturation as \sqrt{L} and Log L with system length L in
the 1D and 2D cases respectively.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:06:46 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 16:42:40 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"San-Jose",
"P.",
""
],
[
"Prada",
"E.",
""
],
[
"Golubev",
"D. S.",
""
]
] |
0706.3833 | Jinsong Sheng Mr. | J. S. Sheng and Kai Chang | Spin states and persistent currents in a mesoscopic ring with an
embedded magnetic impurity | 8 pages, 11 figures | null | 10.1088/0953-8984/20/02/025222 | null | cond-mat.mes-hall | null | Spin states and persistent currents are investigated theoretically in a
mesoscopic ring with an embedded magnetic ion under a uniform magnetic field
including the spin-orbit interactions. The magnetic impurity acts as a
spin-dependent $\delta$-potential for electrons and results in gaps in the
energy spectrum, consequently suppresses the oscillation of the persistent
currents. The competition between the Zeeman splittings and the $s$-$d$
exchange interaction leads to a transition of the electron ground state in the
ring. The interplay between the periodic potential induced by the Rashba and
Dresselhaus spin-orbit interactions and the $\delta$-potential induced by the
magnetic impurity leads to significant variation in the energy spectrum, charge
density distribution, and persistent currents of electrons in the ring.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:00:53 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Sheng",
"J. S.",
""
],
[
"Chang",
"Kai",
""
]
] |
0706.3834 | Andrea Abrardo | A. Abrardo | Design of optimal convolutional codes for joint decoding of correlated
sources in wireless sensor networks | regular paper, 24 pages 10 figures | null | null | null | cs.IT math.IT | null | We consider a wireless sensors network scenario where two nodes detect
correlated sources and deliver them to a central collector via a wireless link.
Differently from the Slepian-Wolf approach to distributed source coding, in the
proposed scenario the sensing nodes do not perform any pre-compression of the
sensed data. Original data are instead independently encoded by means of
low-complexity convolutional codes. The decoder performs joint decoding with
the aim of exploiting the inherent correlation between the transmitted sources.
Complexity at the decoder is kept low thanks to the use of an iterative joint
decoding scheme, where the output of each decoder is fed to the other decoder's
input as a-priori information. For such scheme, we derive a novel analytical
framework for evaluating an upper bound of joint-detection packet error
probability and for deriving the optimum coding scheme. Experimental results
confirm the validity of the analytical framework, and show that recursive codes
allow a noticeable performance gain with respect to non-recursive coding
schemes. Moreover, the proposed recursive coding scheme allows to approach the
ideal Slepian-Wolf scheme performance in AWGN channel, and to clearly
outperform it over fading channels on account of diversity gain due to
correlation of information.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:08:22 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Abrardo",
"A.",
""
]
] |
0706.3835 | Antonio Frasca Dr | F. Soydugan, A. Frasca, E. Soydugan, S. Catalano, O. Demircan, and C.
Ibanoglu | A Spectroscopic Study of the Algol-type Binaries S Equulei and KO
Aquilae: Absolute Parameters and Mass Transfer | 19 pages | Mon.Not.Roy.Astron.Soc.379:1533-1545,2007 | 10.1111/j.1365-2966.2007.12065.x | null | astro-ph | null | We present and analyze high-resolution optical spectra of the Algol binaries
S Equ and KO Aql. New accurate radial velocities for the hotter primary
components are obtained. Thanks to the cross-correlation procedure, we were
able to measure, for the first time to our knowledge, radial velocities also
for the cool secondary components of S Equ and KO Aql. By combining the
parameters obtained from the solution of the radial velocity curves with those
obtained from the light curve analysis, reliable absolute parameters of the
systems have been derived. The rotational velocity of the hotter components of
S Equ and KO Aql has been measured and it is found that the gainers of both
systems rotate about 30 % faster than synchronously. This is likely due to mass
transfer across the Lagrangian L1 point from the cooler to the hotter
component. The lower luminosity of the mass-gaining components of these systems
compared to normal main-sequence stars of the same mass can be also an effect
of the mass transfer. The H-alpha profiles reveal clear evidence of mass
transfer and accretion structures. In both systems we clearly observed
extra-absorption lines. From the integrated absorption and the radial velocity
variations of these features, we found that the mass accretion is very dense
around the impact region of the hotter components. A double-peaked emission in
the spectra of S Equ was seen outside the eclipses. One of these peaks is
likely originated in a region between the center of mass and the cooler
component, which is occupied by the flowing matter. Furthermore, the H-alpha
difference spectra of S Equ and KO Aql display also emission features, which
should be arising from the magnetic activity of the cooler components.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:08:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Soydugan",
"F.",
""
],
[
"Frasca",
"A.",
""
],
[
"Soydugan",
"E.",
""
],
[
"Catalano",
"S.",
""
],
[
"Demircan",
"O.",
""
],
[
"Ibanoglu",
"C.",
""
]
] |
0706.3836 | Petr Bydzovsky | P. Bydzovsky, M. Sotona, T. Motoba, K. Itonaga, K. Ogawa, and O.
Hashimoto | Photo- and electro-production of medium mass Lambda-hypernuclei | 30 pages, 12 figures, submitted to Phys. Rev. C | null | null | null | nucl-th | null | The characteristic and selective nature of the electro-magnetic production of
Lambda-hypernuclei in exciting states is demonstrated assuming the medium-mass
targets 28Si, 40Ca, and 52Cr. Formalism of DWIA is used adopting the
Saclay-Lyon, Kaon-MAID, Adelseck-Saghai, and Williams-Ji-Cotanch models for the
elementary amplitudes and various nuclear and hypernuclear wave functions. The
elementary amplitudes are discussed in detail presenting their basic properties
and comparison with data. The unique features of the electro-magnetic
production of Lambda-hypernuclei shown on examples are the slective excitation
of unnatural parity highest-spin states (natural parity ones for the LS-closed
targets) and a possibilty to investigate the Lambda single-particle energies
including a spin-orbit splitting using variety of medium-mass targets.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:13:50 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Bydzovsky",
"P.",
""
],
[
"Sotona",
"M.",
""
],
[
"Motoba",
"T.",
""
],
[
"Itonaga",
"K.",
""
],
[
"Ogawa",
"K.",
""
],
[
"Hashimoto",
"O.",
""
]
] |
0706.3837 | Robert Petit | Robert Petit (LMJL) | Mok-Siu-Yeung type formulas on contact locally sub-symmetric spaces | 41 pages | null | null | null | math.DG | null | We derive Mok-Siu-Yeung type formulas for horizontal maps from compact
contact locally sub-symmetric spaces into strictly pseudoconvex CR manifolds
and we obtain some rigidity theorems for the horizontal pseudoharmonic maps.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:14:29 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Petit",
"Robert",
"",
"LMJL"
]
] |
0706.3838 | Rob Fender | Rob Fender (Southampton), Elmar Koerding, Tomaso Belloni, Phil Uttley,
Ian McHardy, Tasso Tzioumis | Eight powers of ten: similarities in black hole accretion on all mass
scales | Invited Review at the VI Microquasar Workshop: Microquasars and
beyond, Sept 18-22 2006, Como, Italy. To be published online by PoS | null | null | null | astro-ph | null | In this paper we discuss the recent advances in the quantitative comparison
of accretion, and the accretion:jet coupling, in accreting black holes in both
X-ray binaries (where M ~ 10Msun) and Active Galactic Nuclei (10^5Msun < M <
10^9Msun). These similarities include the radiative efficiency and jet power as
a function of accretion rate, which are themselves probably the origin of the
`fundamental plane of black hole activity'. A second `fundamental plane' which
connects mass, accretion rate and timing properties provides us with a further
physical diagnostic. Patterns of radio loudness (i.e. jet production) as a
function of luminosity and accretion state are shown to be similar for X-ray
binaries and AGN. Finally we discuss how neutron stars are a useful control
sample, and what the future may hold for this field.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:14:30 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Fender",
"Rob",
"",
"Southampton"
],
[
"Koerding",
"Elmar",
""
],
[
"Belloni",
"Tomaso",
""
],
[
"Uttley",
"Phil",
""
],
[
"McHardy",
"Ian",
""
],
[
"Tzioumis",
"Tasso",
""
]
] |
0706.3839 | Rob Fender | R P Fender (Southampton), M Dahlem, J Homan, S Corbel, R Sault, T M
Belloni | The variable radio counterpart and possible large-scale jet of the new
Z-source XTE J1701-462 | Accepted for publication as a Letter in MNRAS | null | 10.1111/j.1745-3933.2007.00350.x | null | astro-ph | null | We report radio observations, made with the Australia Telescope Compact
Array, of the X-ray transient XTE J1701-462. This system has been classified as
a new `Z' source, displaying characteristic patterns of behaviour probably
associated with accretion onto a low magnetic field neutron star at close to
the Eddington limit. The radio counterpart is highly variable, and was detected
in six of sixteen observations over the period 2006 January -- April. The
coupling of radio emission to X-ray state, despite limited sampling, appears to
be similar to that of other `Z' sources, in that there is no radio emission on
the flaring branch. The mean radio and X-ray luminosities are consistent with
the other Z sources for a distance of 5--15 kpc. The radio spectrum is
unusually flat, or even inverted, in contrast to the related sources, Sco X-1
and Cir X-1, which usually display an optically thin radio spectrum. Deep
wide-field observations indicate an extended structure three arcminutes to the
south which is aligned with the X-ray binary. This seems to represent a
significant overdensity of radio sources for the field and so, although a
background source remains a strong possibility, we consider it plausible that
this is a large-scale jet associated with XTE J1701-462.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:14:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fender",
"R P",
"",
"Southampton"
],
[
"Dahlem",
"M",
""
],
[
"Homan",
"J",
""
],
[
"Corbel",
"S",
""
],
[
"Sault",
"R",
""
],
[
"Belloni",
"T M",
""
]
] |
0706.3840 | Aude Barbara | J. Le Perchec, P. Quemerais, A. Barbara, T. Lopez-Rios | Why metallic surfaces with grooves a few nanometers deep and wide may
strongly absorb visible light | 5 pages, 5 figure, submitted to Phys. Rev. Lett | null | 10.1103/PhysRevLett.100.066408 | null | cond-mat.other | null | It is theoretically shown that nanometric silver lamellar gratings present
very strong visible light absorption inside the grooves, leading to electric
field intensities by several orders of magnitude larger than that of the
impinging light. This effect, due to the excitation of long wave vector surface
plasmon polaritons with particular small penetration depth in the metal, may
explain the abnormal optical absorption observed a long time ago on almost flat
Ag films. Surface enhanced Raman scattering in rough metallic films could also
be due to the excitation of such plasmon polaritons in the grain boundaries or
notches of the films.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:20:30 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Nov 2007 13:39:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Perchec",
"J. Le",
""
],
[
"Quemerais",
"P.",
""
],
[
"Barbara",
"A.",
""
],
[
"Lopez-Rios",
"T.",
""
]
] |
0706.3841 | D. B. McReynolds | D. B. McReynolds | Arithmetic lattices and weak spectral geometry | To appear in workshop proceedings for "Topology, Complex Analysis and
Arithmetic of Hyperbolic Spaces". Comments welcome | Topology, complex analysis, and arithmetic of hyperbolic spaces,
RIMS 2007 (1571), 59-81 | null | null | math.DG math.GT | null | This note is an expansion of three lectures given at the workshop "Topology,
Complex Analysis and Arithmetic of Hyperbolic Spaces" held at Kyoto University
in December of 2006 and will appear in the proceedings for this workshop.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 19:16:13 GMT"
}
] | 2009-01-26T00:00:00 | [
[
"McReynolds",
"D. B.",
""
]
] |
0706.3842 | Shunsuke Takagi | Shunsuke Takagi and Ryo Takahashi | D-modules over rings with finite F-representation type | 19 pages; v.2: minor changes, to appear in Math. Res. Lett | null | null | null | math.AC math.AG | null | Smith and Van den Bergh introduced the notion of finite F-representation type
as a characteristic $p$ analogue of the notion of finite representation type.
In this paper, we prove two finiteness properties of rings with finite
F-representation type. The first property states that if $R=\bigoplus_{n \ge
0}R_n$ is a Noetherian graded ring with finite (graded) F-representation type,
then for every non-zerodivisor $x \in R$, $R_x$ is generated by $1/x$ as a
$D_{R}$-module. The second one states that if $R$ is a Gorenstein ring with
finite F-representation type, then $H_I^n(R)$ has only finitely many associated
primes for any ideal $I$ of $R$ and any integer $n$. We also include a result
on the discreteness of F-jumping exponents of ideals of rings with finite
(graded) F-representation type as an appendix.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:33:23 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Dec 2007 16:05:07 GMT"
}
] | 2007-12-19T00:00:00 | [
[
"Takagi",
"Shunsuke",
""
],
[
"Takahashi",
"Ryo",
""
]
] |
0706.3843 | Aude Barbara | A. Barbara, J. Le Perchec, P. Quemerais, T. Lopez-Rios, S. Collin, C.
Sauvan, J-L. Pelouard | Role of commensurate arrangements in the optical response of metallic
gratings | 5 pages, 5 figures, submitted to Phys. Rev. Lett. May 2007 | null | null | null | cond-mat.other | null | Light localization on commensurate arrangements of metallic sub-wavelength
grooves is studied. We theoretically show that as the degree of commensuration
tends to an irrational number new light localization states are produced. These
have properties close to that reported for hot spots on disordered surfaces and
are not permitted for simple period gratings. Some theoretical predictions are
experimentally provided in the infra-red region by reflectivity measurements
performed on two commensurate samples with respectively two and three slits per
period.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:31:22 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Nov 2007 14:09:09 GMT"
}
] | 2007-11-05T00:00:00 | [
[
"Barbara",
"A.",
""
],
[
"Perchec",
"J. Le",
""
],
[
"Quemerais",
"P.",
""
],
[
"Lopez-Rios",
"T.",
""
],
[
"Collin",
"S.",
""
],
[
"Sauvan",
"C.",
""
],
[
"Pelouard",
"J-L.",
""
]
] |
0706.3844 | Ali Mostafazadeh | Ali Mostafazadeh | Quantum Brachistochrone Problem and the Geometry of the State Space in
Pseudo-Hermitian Quantum Mechanics | A minor error in equation (8) is corrected, 4 pages | Phys. Rev. Lett. 99, 130502 (2007) | 10.1103/PhysRevLett.99.130502 | null | quant-ph hep-th math-ph math.MP | null | A non-Hermitian operator with a real spectrum and a complete set of
eigenvectors may serve as the Hamiltonian operator for a unitary quantum system
provided that one makes an appropriate choice for the defining inner product of
the physical Hilbert state. We study the consequences of such a choice for the
representation of states in terms of projection operators and the geometry of
the state space. This allows for a careful treatment of the quantum
Brachistochrone problem and shows that it is indeed impossible to achieve
faster unitary evolutions using PT-symmetric or other non-Hermitian
Hamiltonians than those given by Hermitian Hamiltonians.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:34:15 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 07:46:08 GMT"
},
{
"version": "v3",
"created": "Wed, 17 Oct 2007 07:46:19 GMT"
},
{
"version": "v4",
"created": "Thu, 10 Apr 2008 09:10:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mostafazadeh",
"Ali",
""
]
] |
0706.3845 | Diego Guadagnoli | Wolfgang Altmannshofer, Andrzej J. Buras, Diego Guadagnoli and Michael
Wick | Large |Vub|: A challenge for the Minimal Flavour Violating MSSM | 1+17 pages, 6 figures, 3 tables. v3: various modifications in the
text, in the choice of the input and in the numerics. Results unchanged.
References extended. Matches JHEP published version | JHEP 0712:096,2007 | 10.1088/1126-6708/2007/12/096 | TUM-HEP-670/07 | hep-ph | null | Under the assumption of Minimal Flavour Violation (MFV), the Unitarity
Triangle (UT) can be determined by using only angle measurements and tree-level
observables. In this respect, the most accurate quantities today available are
sin 2 beta_{psi Ks}, |Vcb| and |Vub|. Among the latter, |Vub| is at present the
quantity suffering from largest systematic uncertainties, given the discrepancy
between the inclusive and the exclusive determinations.
We show with a numerical fit how sensitively the MFV-UT determination depends
on the choice of |Vub|. In addition, we focus on the implications of the
inclusive value for |Vub|, which favors two non-SM like solutions in the rhobar
- etabar plane. We study in detail the possibility of reproducing such
solutions within the MFV MSSM. Our findings indicate that the case for the MFV
MSSM is in this respect quite problematic, unless the non-perturbative
parameters xi and BK are significantly different from those obtained by lattice
methods. As a byproduct, we point out that scenarios with 200 GeV <~ MA <~ 500
GeV and tan beta =~ 50 that predict a significant suppression for Delta Ms in
correlation with an enhancement for BR(Bs --> mu^+ mu^-) have to be fine-tuned
in order not to violate the new combined bound on the latter decay mode from
the CDF and D0 collaborations. Relatively large correlated effects can however
still occur for negative values of mu and large values for MA >~ 500 GeV,
increasing with increasing tan beta >~ 30.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:37:59 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 11:11:57 GMT"
},
{
"version": "v3",
"created": "Tue, 1 Jan 2008 21:02:17 GMT"
}
] | 2009-01-06T00:00:00 | [
[
"Altmannshofer",
"Wolfgang",
""
],
[
"Buras",
"Andrzej J.",
""
],
[
"Guadagnoli",
"Diego",
""
],
[
"Wick",
"Michael",
""
]
] |
0706.3846 | Man-On Pun | Man-On Pun, Visa Koivunen and H. Vincent Poor | Opportunistic Scheduling and Beamforming for MIMO-SDMA Downlink Systems
with Linear Combining | To appear in the Proceedings of the 18th Annual IEEE International
Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC),
Athens, Greece, September 3 - 7, 2007 | null | 10.1109/PIMRC.2007.4394179 | null | cs.IT math.IT | null | Opportunistic scheduling and beamforming schemes are proposed for multiuser
MIMO-SDMA downlink systems with linear combining in this work. Signals received
from all antennas of each mobile terminal (MT) are linearly combined to improve
the {\em effective} signal-to-noise-interference ratios (SINRs). By exploiting
limited feedback on the effective SINRs, the base station (BS) schedules
simultaneous data transmission on multiple beams to the MTs with the largest
effective SINRs. Utilizing the extreme value theory, we derive the asymptotic
system throughputs and scaling laws for the proposed scheduling and beamforming
schemes with different linear combining techniques. Computer simulations
confirm that the proposed schemes can substantially improve the system
throughput.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:33:32 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Pun",
"Man-On",
""
],
[
"Koivunen",
"Visa",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0706.3847 | Oleg Kalashev E | O.Kalashev, G.Gelmini, D.Semikoz | Constraints on secondary 10-100 EeV gamma ray flux in the minimal
bottom-up model of Ultra High Energy Cosmic Rays | Contribution to the 30th International Cosmic Ray Conference, Merida,
Mexico, July 2007, 4 pages, 4 figures | null | null | null | astro-ph | null | In a recently proposed model the cosmic rays spectrum at energies above EeV
can be fitted with a minimal number of unknown parameters assuming that the
extragalactic cosmic rays are only protons with a power law source spectrum.
Within this minimal model, after fitting the observed HiRes spectrum with four
parameters (proton injection spectrum power law index, maximum energy, minimum
distance to sources and evolution parameter) we compute the flux of ultra-high
energy photons due to photon-pion production and e+e- pair production by
protons for several radio background models and a range of average
extragalactic magnetic fields.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:41:02 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Kalashev",
"O.",
""
],
[
"Gelmini",
"G.",
""
],
[
"Semikoz",
"D.",
""
]
] |
0706.3848 | Vlady Ravelomanana | Jean Cardinal (ULB), Vlady Ravelomanana (LIPN), Mario Valencia-Pabon
(LIPN) | Minimum Sum Edge Colorings of Multicycles | null | null | null | null | cs.DM | null | In the minimum sum edge coloring problem, we aim to assign natural numbers to
edges of a graph, so that adjacent edges receive different numbers, and the sum
of the numbers assigned to the edges is minimum. The {\em chromatic edge
strength} of a graph is the minimum number of colors required in a minimum sum
edge coloring of this graph. We study the case of multicycles, defined as
cycles with parallel edges, and give a closed-form expression for the chromatic
edge strength of a multicycle, thereby extending a theorem due to Berge. It is
shown that the minimum sum can be achieved with a number of colors equal to the
chromatic index. We also propose simple algorithms for finding a minimum sum
edge coloring of a multicycle. Finally, these results are generalized to a
large family of minimum cost coloring problems.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:43:15 GMT"
},
{
"version": "v2",
"created": "Tue, 22 Jan 2008 13:36:41 GMT"
}
] | 2008-01-22T00:00:00 | [
[
"Cardinal",
"Jean",
"",
"ULB"
],
[
"Ravelomanana",
"Vlady",
"",
"LIPN"
],
[
"Valencia-Pabon",
"Mario",
"",
"LIPN"
]
] |
0706.3849 | Brouet Veronique | V. Brouet, A. Nicolaou, M. Zacchigna, A. Tejeda, L. Patthey, S.
Hebert, W. Kobayashi, H. Muguerra and D. Grebille | Direct observation of strong correlations near the band insulator regime
of Bi misfit cobaltates | 4 pages, 4 figures | null | 10.1103/PhysRevB.76.100403 | null | cond-mat.str-el | null | We present the first angle-resolved photoemission (ARPES) measurement of
Fermi Surface in the "misfit" cobaltate [Bi2Ba2O4].[CoO2]~2. This compound
contains the same triangular Co planes as Na cobaltates, but in a different 3D
environment. Our data establish the similarity of their electronic structure.
We propose that the peculiar lineshape of all cobaltates is of the
"peak-dip-hump" type, due to strong many-body effects. We detect a progressive
transfer of spectral weight from the quasiparticle feature near Ef to a broad
hump in misfit phases where Ba is replaced by Sr or Ca. This indicates stronger
many-body interactions in proximity of the band insulator regime, which we
attribute to the presence of unusual magnetic excitations.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:47:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Brouet",
"V.",
""
],
[
"Nicolaou",
"A.",
""
],
[
"Zacchigna",
"M.",
""
],
[
"Tejeda",
"A.",
""
],
[
"Patthey",
"L.",
""
],
[
"Hebert",
"S.",
""
],
[
"Kobayashi",
"W.",
""
],
[
"Muguerra",
"H.",
""
],
[
"Grebille",
"D.",
""
]
] |
0706.3850 | Andreas Just | A. Just, H. Jahreiss | The local star formation history of the thin disc derived from kinematic
data | a completely revised version can be found at astroph 0910.3481 and is
published in MNRAS (reference see below) | null | null | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present an evolutionary disc model for the thin disc in the solar cylinder
based on a continuous star formation history and a continuous dynamical heating
of the stellar subpopulations. The vertical distribution of the stellar
subpopulations are calculated self-consistently in dynamical equilibrium. The
SFR and AVR of the stellar subpopulations are determined by fitting the
velocity distribution functions of main sequence stars. The SFR shows a maximum
10 Gyr ago declining by a factor of 10 until present time. A constant SFR can
be ruled out. The velocity dispersion of the stellar subpopulations increase
with age according to a power law with index 0.375. The new scale heights lead
to a best fit IMF with power-law indices of 1.5 below and 4.0 above 1.6 Msun,
which has no kink around 1 Msun. Including a thick disc component results in
slight variations of the thin disc properties, but has a negligible influence
on the SFR. A variety of predictions are made concerning the number density,
age and metallicity distributions of stellar subpopulations as a function of z
above the galactic plane.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:18:30 GMT"
},
{
"version": "v2",
"created": "Mon, 27 Dec 2010 16:28:37 GMT"
}
] | 2016-04-26T00:00:00 | [
[
"Just",
"A.",
""
],
[
"Jahreiss",
"H.",
""
]
] |
0706.3851 | Marcin Molski | Marcin Molski | A General Scheme for Construction of Coherent States of Anharmonic
Oscillators | 5 pages. Submitted to Physical Review Letters | null | null | null | quant-ph | null | A mixed supersymmetric-algebraic approach to construction of the minimum
uncertainty coherent states of anharmonic oscillators is presented. It permits
generating not only the well-known coherent states of the harmonic and Morse
oscillators but also the so far unknown coherent states of the Wei Hua,
Kratzer-Fues and generalized Morse and Kratzer-Fues oscillators. The method can
be applied also to generate superpotentials indispensable for deriving the
Schr\"odinger equation in the supersymmetric form amenable to direct solution
in the SUSYQM scheme.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 14:58:13 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Molski",
"Marcin",
""
]
] |
0706.3852 | Martin Hutzenthaler | Roland Alkemper, Martin Hutzenthaler | Graphical Representation of some Duality Relations in Stochastic
Population Models | 17 pages, 3 figures | Electron. Comm. Probab. 12 (2007), 206--220 | null | null | math.PR | null | We derive a unified stochastic picture for the duality of a
resampling-selection model with a branching-coalescing particle process (cf.
http://www.ams.org/mathscinet-getitem?mr=MR2123250) and for the self-duality of
Feller's branching diffusion with logistic growth (cf. math/0509612). The two
dual processes are approximated by particle processes which are forward and
backward processes in a graphical representation. We identify duality relations
between the basic building blocks of the particle processes which lead to the
two dualities mentioned above.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:49:14 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Alkemper",
"Roland",
""
],
[
"Hutzenthaler",
"Martin",
""
]
] |
0706.3853 | Vladimir Galkin | D. Ebert, R. N. Faustov, V. O. Galkin, W. Lucha | Masses of tetraquarks with two heavy quarks in the relativistic quark
model | 12 pages; version to be published in Phys.Rev.D | Phys.Rev.D76:114015,2007 | 10.1103/PhysRevD.76.114015 | HU-EP-07/21, HEPHY-PUB 842/07 | hep-ph | null | Masses of tetraquarks with two heavy quarks and open charm and bottom are
calculated in the framework of the diquark-antidiquark picture in the
relativistic quark model. All model parameters were regarded as fixed by
previous considerations of various properties of mesons and baryons. The light
quarks and diquarks are treated completely relativistically. The c quark is
assumed to be heavy enough to make the diquark configurations dominating. The
diquarks are considered not to be point-like but to have an internal structure
which is taken into account by the calculated diquark form factor entering the
diquark-gluon interaction. It is found that all the (cc)(\bar q\bar q')
tetraquarks have masses above the thresholds for decays into open charm mesons.
Only the I(J^P)=0(1^+) state of (bb)(\bar u\bar d) lies below the BB* threshold
and is predicted to be narrow.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:02:16 GMT"
},
{
"version": "v2",
"created": "Wed, 21 Nov 2007 14:51:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ebert",
"D.",
""
],
[
"Faustov",
"R. N.",
""
],
[
"Galkin",
"V. O.",
""
],
[
"Lucha",
"W.",
""
]
] |
0706.3854 | Sven Bjarke Gudnason | Luca Ferretti (SISSA, INFN Trieste), Sven Bjarke Gudnason and Kenichi
Konishi (University of Pisa, INFN Pisa) | Non-Abelian vortices and monopoles in SO(N) theories | LaTeX, 26 pages and 4 figures | Nucl.Phys.B789:84-110,2008 | 10.1016/j.nuclphysb.2007.07.021 | IFUP-TH/2007-16; SISSA-47/2007/EP | hep-th | null | Non-Abelian BPS vortex solutions are constructed in N=2 theories with gauge
groups SO(N)\times U(1). The model has N_f flavors of chiral multiplets in the
vector representation of SO(N), and we consider a color-flavor locked vacuum in
which the gauge symmetry is completely broken, leaving a global SO(N)_{C+F}
diagonal symmetry unbroken. Individual vortices break this symmetry, acquiring
continuous non-Abelian orientational moduli. By embedding this model in
high-energy theories with a hierarchical symmetry breaking pattern such as
SO(N+2) --> SO(N)\times U(1) --> 1, the correspondence between non-Abelian
monopoles and vortices can be established through homotopy maps and flux
matching, generalizing the known results in SU(N) theories. We find some
interesting hints about the dual (non-Abelian) transformation properties among
the monopoles.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:22:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ferretti",
"Luca",
"",
"SISSA, INFN Trieste"
],
[
"Gudnason",
"Sven Bjarke",
"",
"University of Pisa, INFN Pisa"
],
[
"Konishi",
"Kenichi",
"",
"University of Pisa, INFN Pisa"
]
] |
0706.3855 | Yaron Sheffer | Y. Sheffer, M. Rogers, S. R. Federman (U. Toledo), D. L. Lambert (U.
Texas at Austin), and R. Gredel (MPIfA) | Hubble Space Telescope Survey of Interstellar ^12CO/^13CO in the Solar
Neighborhood | 1-column emulateapj, 23 pages, 9 figures | Astrophys.J. 667 (2007) 1002-1016 | 10.1086/520875 | null | astro-ph | null | We examine 20 diffuse and translucent Galactic sight lines and extract the
column densities of the ^12CO and ^13CO isotopologues from their ultraviolet
A--X absorption bands detected in archival Space Telescope Imaging Spectrograph
data with lambda/Deltalambda geq 46,000. Five more targets with Goddard
High-Resolution Spectrograph data are added to the sample that more than
doubles the number of sight lines with published Hubble Space Telescope
observations of ^13CO. Most sight lines have 12-to-13 isotopic ratios that are
not significantly different from the local value of 70 for ^12C/^13C, which is
based on mm-wave observations of rotational lines in emission from CO and H_2CO
inside dense molecular clouds, as well as on results from optical measurements
of CH^+. Five of the 25 sight lines are found to be fractionated toward lower
12-to-13 values, while three sight lines in the sample are fractionated toward
higher ratios, signaling the predominance of either isotopic charge exchange or
selective photodissociation, respectively. There are no obvious trends of the
^12CO-to-^13CO ratio with physical conditions such as gas temperature or
density, yet ^12CO/^13CO does vary in a complicated manner with the column
density of either CO isotopologue, owing to varying levels of competition
between isotopic charge exchange and selective photodissociation in the
fractionation of CO. Finally, rotational temperatures of H_2 show that all
sight lines with detected amounts of ^13CO pass through gas that is on average
colder by 20 K than the gas without ^13CO. This colder gas is also sampled by
CN and C_2 molecules, the latter indicating gas kinetic temperatures of only 28
K, enough to facilitate an efficient charge exchange reaction that lowers the
value of ^12CO/^13CO.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:13:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sheffer",
"Y.",
"",
"U. Toledo"
],
[
"Rogers",
"M.",
"",
"U. Toledo"
],
[
"Federman",
"S. R.",
"",
"U. Toledo"
],
[
"Lambert",
"D. L.",
"",
"U.\n Texas at Austin"
],
[
"Gredel",
"R.",
"",
"MPIfA"
]
] |
0706.3856 | Jean-Luc Marichal | Jean-Luc Marichal, Pierre Mathonet | Approximations of Lovasz extensions and their induced interaction index | 19 pages | Discrete Applied Mathematics 156 (1) (2008) 11-24 | null | null | math.CO cs.DM | null | The Lovasz extension of a pseudo-Boolean function $f : \{0,1\}^n \to R$ is
defined on each simplex of the standard triangulation of $[0,1]^n$ as the
unique affine function $\hat f : [0,1]^n \to R$ that interpolates $f$ at the
$n+1$ vertices of the simplex. Its degree is that of the unique multilinear
polynomial that expresses $f$. In this paper we investigate the least squares
approximation problem of an arbitrary Lovasz extension $\hat f$ by Lovasz
extensions of (at most) a specified degree. We derive explicit expressions of
these approximations. The corresponding approximation problem for
pseudo-Boolean functions was investigated by Hammer and Holzman (1992) and then
solved explicitly by Grabisch, Marichal, and Roubens (2000), giving rise to an
alternative definition of Banzhaf interaction index. Similarly we introduce a
new interaction index from approximations of $\hat f$ and we present some of
its properties. It turns out that its corresponding power index identifies with
the power index introduced by Grabisch and Labreuche (2001).
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:14:06 GMT"
}
] | 2010-11-19T00:00:00 | [
[
"Marichal",
"Jean-Luc",
""
],
[
"Mathonet",
"Pierre",
""
]
] |
0706.3857 | Peter A. M. van Hoof | P.A.M. van Hoof, M. Hajduk, Albert A. Zijlstra, F. Herwig, A. Evans,
G.C Van de Steene, S. Kimeswenger, F. Kerber, S.P.S. Eyres | The onset of photoionization in Sakurai's Object (V4334 Sgr) | 4 pages, 2 figures; accepted for publication in A&A letters | null | 10.1051/0004-6361:20077932 | null | astro-ph | null | We investigate the reheating of the very late thermal pulse (VLTP) object
V4334 Sgr (Sakurai's Object) using radio observations from the Very Large
Array, and optical spectra obtained with the Very Large Telescope. We find a
sudden rise of the radio flux at 5 and 8 GHz - from <= 90 micro-Jy and 80 +/-
30 micro-Jy in February 2005 to 320 micro-Jy and 280 micro-Jy in June 2006.
Optical line emission is also evolving, but the emission lines are fading. The
optical line emission and early radio flux are attributed to a fast shock (and
not photoionization as was reported earlier) which occurred around 1998. The
fading is due to post-shock cooling and recombination. The recent rapid
increase in radio flux is evidence for the onset of photoionization of carbon
starting around 2005. The current results indicate an increase in the stellar
temperature to 12 kK in 2006. The mass ejected in the VLTP eruption is M_ej >=
1e-4 Msol, but could be as high as 1e-2 Msol, depending mainly on the distance
and the clumping factor of the outflow. We derive a distance between 1.8 and 5
kpc. A high mass loss could expose the helium layer and yield abundances
compatible with those of [WC] and PG1159 stars.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:17:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"van Hoof",
"P. A. M.",
""
],
[
"Hajduk",
"M.",
""
],
[
"Zijlstra",
"Albert A.",
""
],
[
"Herwig",
"F.",
""
],
[
"Evans",
"A.",
""
],
[
"Van de Steene",
"G. C",
""
],
[
"Kimeswenger",
"S.",
""
],
[
"Kerber",
"F.",
""
],
[
"Eyres",
"S. P. S.",
""
]
] |
0706.3858 | Paul McClarty | P. A. McClarty | A study of a local Monte Carlo technique for simulating systems of
charged particles | 17 pages, 10 figures | null | null | null | cond-mat.stat-mech cond-mat.soft | null | We study some aspects of a Monte Carlo method invented by Maggs and Rossetto
for simulating systems of charged particles. It has the feature that the
discretized electric field is updated locally when charges move. Results of
simulations of the two dimensional one-component plasma are presented. Highly
accurate results can be obtained very efficiently using this lattice method
over a large temperature range. The method differs from global methods in
having additional degrees of freedom which leads to the question of how a
faster method can result. We argue that efficient sampling depends on charge
mobility and find that the mobility is close to maximum for a low rate of
independent plaquette updates for intermediate temperatures. We present a
simple model to account for this behavior. We also report on the role of
uniform electric field sampling using this method.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:18:04 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"McClarty",
"P. A.",
""
]
] |
0706.3859 | Alessandro Olmi | S. Piantelli, P.R. Maurenzig, A. Olmi, L. Bardelli, M. Bini, G.
Casini, A. Mangiarotti, G. Pasquali, G. Poggi, A.A. Stefanini | Distinctive features of Coulomb-related emissions in peripheral heavy
ion collisions at Fermi energies | 4 pages, 3 figures, RevTex 4.0 | Phys.Rev.C76:061601,2007 | 10.1103/PhysRevC.76.061601 | null | nucl-ex | null | Light charged particles emitted at about 90 deg in the frame of the
projectile-like fragment in semi-peripheral collisions of 93Nb+93Nb at 38A MeV
give evidence for the simultaneous occurrence of two different production
mechanisms. This is demonstrated by differences in the kinetic energy spectra
and in the isotopic composition of the particles. The emission with a softer
kinetic energy spectrum and a low N/Z ratio for the hydrogen isotopes is
attributed to an evaporation process. The harder emission, with a much higher
N/Z ratio, can be attributed to a ``midvelocity'' process consisting of a
non-isotropic emission, on a short time-scale, from the surface of the
projectile-like fragment.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:18:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Piantelli",
"S.",
""
],
[
"Maurenzig",
"P. R.",
""
],
[
"Olmi",
"A.",
""
],
[
"Bardelli",
"L.",
""
],
[
"Bini",
"M.",
""
],
[
"Casini",
"G.",
""
],
[
"Mangiarotti",
"A.",
""
],
[
"Pasquali",
"G.",
""
],
[
"Poggi",
"G.",
""
],
[
"Stefanini",
"A. A.",
""
]
] |
0706.3860 | Diego Pavon | German Olivares, Fernando Atrio-Barandela and Diego Pavon | Dynamics of Interacting Quintessence Models: Observational Constraints | 16 pages, 7 figures and 3 tables. Modifications introduced to match
published version | Phys.Rev.D77:063513,2008 | 10.1103/PhysRevD.77.063513 | null | astro-ph gr-qc hep-ph | null | Interacting quintessence models have been proposed to explain or, at least,
alleviate the coincidence problem of late cosmic acceleration. In this paper we
are concerned with two aspects of these kind of models: (i) the dynamical
evolution of the model of Chimento et al. [L.P. Chimento, A.S. Jakubi, D.
Pavon, and W. Zimdahl, Phys. Rev. D 67, 083513 (2003).], i.e., whether its
cosmological evolution gives rise to a right sequence of radiation, dark matter
and dark energy dominated eras, and (ii) whether the dark matter dark energy
ratio asymptotically evolves towards a non-zero constant. After showing that
the model correctly reproduces these eras, we correlate three data sets that
constrain the interaction at three redshift epochs: $z\le 10^{4}$, $z=10^{3}$,
and $z=1$. We discuss the model selection and argue that even if the model
under consideration fulfills both requirements, it is heavily constrained by
observation. The prospects that the coincidence problem can be explained by the
coupling of dark matter to dark energy are not clearly favored by the data.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:32:23 GMT"
},
{
"version": "v2",
"created": "Tue, 29 Jan 2008 15:01:44 GMT"
},
{
"version": "v3",
"created": "Tue, 5 Feb 2008 10:29:09 GMT"
},
{
"version": "v4",
"created": "Mon, 10 Mar 2008 12:56:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Olivares",
"German",
""
],
[
"Atrio-Barandela",
"Fernando",
""
],
[
"Pavon",
"Diego",
""
]
] |
0706.3861 | Valentin Ferenczi | Valentin Ferenczi and Eloi Medina Galego | Countable groups of isometries on Banach spaces | 44 pages | null | null | null | math.FA | null | A group G is representable in a Banach space X if G is isomorphic to the
group of isometries on X in some equivalent norm. We prove that a countable
group G is representable in a separable real Banach space X in several general
cases, including when $G=\{-1,1\} \times H$, H finite and $\dim X \geq |H|$, or
when G contains a normal subgroup with two elements and X is of the form c_0(Y)
or $\ell_p(Y)$, $1 \leq p <+\infty$. This is a consequence of a result inspired
by methods of S. Bellenot and stating that under rather general conditions on a
separable real Banach space X and a countable bounded group G of isomorphisms
on X containing -Id, there exists an equivalent norm on X for which G is equal
to the group of isometries on X.
We also extend methods of K. Jarosz to prove that any complex Banach space of
dimension at least 2 may be renormed to admit only trivial real isometries, and
that any real Banach space which is a cartesian square may be renormed to admit
only trivial and conjugation real isometries. It follows that every real space
of dimension at least 4 and with a complex structure up to isomorphism may be
renormed to admit exactly two complex structures up to isometry, and that every
real cartesian square may be renormed to admit a unique complex structure up to
isometry.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:38:55 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 17:11:52 GMT"
},
{
"version": "v3",
"created": "Mon, 30 Jul 2007 19:04:11 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Ferenczi",
"Valentin",
""
],
[
"Galego",
"Eloi Medina",
""
]
] |
0706.3862 | Clare Dobbs | Clare Dobbs, Daniel Price, Ian Bonnell | Molecular cloud formation and magnetic fields in spiral galaxies | To appear in the proceedings for "Pathways Through an Eclectic
Universe", Editors: Johan Knapen, Terry Mahoney, and Alexandre Vazdekis | null | null | null | astro-ph | null | We present ongoing hydrodynamic and MHD simulations of molecular cloud
formation in spiral galaxies. The hydrodynamic results show the formation of
molecular gas clouds where spiral shocks compress atomic gas to high densities.
The spiral shocks also produce structure in the spiral arms, provided the gas
is cold (< 1000 K). When both hot and cold components of the ISM are modeled,
this structure is enhanced. Properties such as the clump mass spectra and
spatial distribution will be compared from clouds identified in these
simulations. In particular the multiphase simulations predict the presence of
much more interarm molecular gas than when a single phase is assumed. We also
discuss very recent results from galactic-scale MHD calculations. From
observational comparisons of the magnetic and thermal pressure, magnetic fields
are expected to be a major factor in explaining the dynamics of the ISM, from
kpc scales to those of star formation. We describe the difference in structure
of the spiral arms, and the evolution of the global magnetic field for a range
of field strengths.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:00:01 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Dobbs",
"Clare",
""
],
[
"Price",
"Daniel",
""
],
[
"Bonnell",
"Ian",
""
]
] |
0706.3863 | Luuk Hoevenaars | L.K. Hoevenaars | Frobenius manifolds and algebraic integrability | 18 pages, 1 figure, to appear in Encyclopedia of Peyresq (2007) | null | null | null | math-ph math.MP | null | We give a short review of Frobenius manifolds and algebraic integrability and
study their intersection. The simplest case is the relation between the
Frobenius manifold of simple singularities, which is almost dual to the
integrable open Toda chain. New types of manifolds called extra special Kaehler
and special F-manifolds are introduced which capture the intersection.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:57:47 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Hoevenaars",
"L. K.",
""
]
] |
0706.3864 | Sachie Kimura | Sachie Kimura and Aldo Bonasera | Isospin Effects on Astrophysical S-Factors | 12 pages, 1 figures | Phys.Rev.C76:031602,2007 | 10.1103/PhysRevC.76.031602 | null | nucl-th | null | We estimate the ratios of bare astrophysical S-factors at zero incident
energy for proton and deuteron induced reactions in a model which assumes a
compound nucleus formation probability plus a statistical decay. The obtained
ratios agree well with available experimental values, as far as the reactions
which have dominant s-wave entrance channel components are investigated. Due to
its simplicity the model could be used as a guidance for predictions on
reactions which have not been investigated yet.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:59:15 GMT"
},
{
"version": "v2",
"created": "Tue, 13 Nov 2007 09:04:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kimura",
"Sachie",
""
],
[
"Bonasera",
"Aldo",
""
]
] |
0706.3865 | John Tomlin | Ralphe Wiggins and John A. Tomlin | Bid Optimization for Internet Graphical Ad Auction Systems via Special
Ordered Sets | null | null | null | YR-2007-004 | cs.DM | null | This paper describes an optimization model for setting bid levels for certain
types of advertisements on web pages. This model is non-convex, but we are able
to obtain optimal or near-optimal solutions rapidly using branch and cut
open-source software. The financial benefits obtained using the prototype
system have been substantial.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 15:59:42 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Wiggins",
"Ralphe",
""
],
[
"Tomlin",
"John A.",
""
]
] |
0706.3866 | Maxim Kharitonov | Maxim Yu. Kharitonov and Konstantin B. Efetov | Hall Transport in Granular Metals and Effects of Coulomb Interactions | 29 pages, 16 figures | Phys. Rev. B 77, 045116 (2008) | 10.1103/PhysRevB.77.045116 | null | cond-mat.mes-hall cond-mat.str-el | null | We present a theory of Hall effect in granular systems at large tunneling
conductance $g_{T}\gg 1$. Hall transport is essentially determined by the
intragrain electron dynamics, which, as we find using the Kubo formula and
diagrammatic technique, can be described by nonzero diffusion modes inside the
grains. We show that in the absence of Coulomb interaction the Hall resistivity
$\rho_{xy}$ depends neither on the tunneling conductance nor on the intragrain
disorder and is given by the classical formula $\rho_{xy}=H/(n^* e c)$, where
$n^*$ differs from the carrier density $n$ inside the grains by a numerical
coefficient determined by the shape of the grains and type of granular lattice.
Further, we study the effects of Coulomb interactions by calculating
first-order in $1/g_T$ corrections and find that (i) in a wide range of
temperatures $T \gtrsim \Ga$ exceeding the tunneling escape rate $\Ga$, the
Hall resistivity $\rho_{xy}$ and conductivity $\sig_{xy}$ acquire logarithmic
in $T$ corrections, which are of local origin and absent in homogeneously
disordered metals; (ii) large-scale ``Altshuler-Aronov'' correction to
$\sig_{xy}$, relevant at $T\ll\Ga$, vanishes in agreement with the theory of
homogeneously disordered metals.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:42:05 GMT"
}
] | 2009-03-25T00:00:00 | [
[
"Kharitonov",
"Maxim Yu.",
""
],
[
"Efetov",
"Konstantin B.",
""
]
] |
0706.3867 | Dan Solomon | Dan Solomon | The Heisenberg versus the Schroedinger picture and the problem of gauge
invariance | 25 pages. Additional material in this revision | null | null | null | quant-ph | null | It is generally assumed that quantum field theory (QFT) is gauge invariant.
However it is well known that non-gauge invariant terms appear in various
calculations. This problem was recently examined in [9] for a "simple" field
theory and it was shown that for this case QFT in the Schroedinger picture is
not, in fact, gauge invariant. In order to shed further light on this problem
we will examine the Heisenberg and Schroedinger formulations of QFT. It is
generally assumed that these two "pictures" are equivalent; however we will
show that this is not necessarily the case. We shall consider a simple field
theory consisting of a quantized fermion field in the presence of a classical
electromagnetic field. We will show that, although the two pictures are
formally equivalent, the Heisenberg picture is gauge invariant but that the
Schroedinger picture is not. This suggests that the proper way to formulate QFT
is to use the Heisenberg picture.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:27:41 GMT"
},
{
"version": "v2",
"created": "Mon, 12 Nov 2007 01:56:53 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Solomon",
"Dan",
""
]
] |
0706.3868 | Jennifer Pursley | CDF Collaboration: T. Aaltonen, et al | First Observation of Heavy Baryons \Sigma_b and \Sigma_b^* | 7 Pages, 2 Figures, 2 Tables. Submitted to Phys. Rev. Lett | Phys.Rev.Lett.99:202001,2007 | 10.1103/PhysRevLett.99.202001 | FERMILAB-PUB-07-318-E | hep-ex | null | We report an observation of new bottom baryons produced in proton-antiproton
collisions at the Tevatron. Using 1.1 fb^{-1} of data collected by the CDF II
detector, we observe four \Lambda_b^0\pi^{\pm} resonances in the fully
reconstructed decay mode \Lambda_b^0 \to \Lambda_c^+ \pi^-, where \Lambda_c^+
\to p K^- \pi^+. We interpret these states as the \Sigma_b^{(*)\pm} baryons and
measure the following masses: m_{\Sigma_b^+} = 5807.8^{+2.0}_{-2.2}(stat.) \pm
1.7(syst.) MeV/c^2, m_{\Sigma_b^-} = 5815.2 \pm 1.0(stat.) \pm 1.7(syst.)
MeV/c^2, and m(\Sigma_b^*) - m(\Sigma_b) = 21.2^{+2.0}_{-1.9}(stat.)
^{+0.4}_{-0.3}(syst.) MeV/c^2.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:38:50 GMT"
},
{
"version": "v2",
"created": "Mon, 12 Nov 2007 17:04:36 GMT"
}
] | 2010-05-12T00:00:00 | [
[
"CDF Collaboration",
"",
""
],
[
"Aaltonen",
"T.",
""
]
] |
0706.3869 | Ulrich Raitzsch | Ulrich Raitzsch, Vera Bendkowsky, Rolf Heidemann, Bj\"orn Butscher,
Robert L\"ow, and Tilman Pfau | An echo experiment in a strongly interacting Rydberg gas | 4 pages, 5 figures | Phys. Rev. Lett. 100, p. 013002 (2008) | 10.1103/PhysRevLett.100.013002 | null | quant-ph | null | When ground state atoms are excited to a Rydberg state, van der Waals
interactions among them can lead to a strong suppression of the excitation.
Despite the strong interactions the evolution can still be reversed by a simple
phase shift in the excitation laser field. We experimentally prove the
coherence of the excitation in the strong blockade regime by applying an
`optical rotary echo' technique to a sample of magnetically trapped ultracold
atoms, analogous to a method known from nuclear magnetic resonance. We
additionally measured the dephasing time due to the interaction between the
Rydberg atoms.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:39:01 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Oct 2007 11:27:59 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Raitzsch",
"Ulrich",
""
],
[
"Bendkowsky",
"Vera",
""
],
[
"Heidemann",
"Rolf",
""
],
[
"Butscher",
"Björn",
""
],
[
"Löw",
"Robert",
""
],
[
"Pfau",
"Tilman",
""
]
] |
0706.3870 | Fritz W. Bopp | F.W.Bopp, R.Engel, J.Ranft, and S.Roesler | Antibaryon to Baryon Production Ratios in Pb-Pb and p-p collision at LHC
energies of the DPMJET-III Monte Carlo | Presented at "Heavy Ion Collisions at the LHC: last call for
predictions", Geneva Switzerland, May 14th-June 8th | Fizika B17:159-166,2008 | null | SI-HEP-2007-09 | hep-ph | null | A sizable component of stopped baryons is predicted for pp and P bP b
collisions at LHC. Based on an analysis of RHIC data within framework of our
multichain Monte Carlo DPMJET-III the LHC predictions are presented.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:45:08 GMT"
}
] | 2009-02-20T00:00:00 | [
[
"Bopp",
"F. W.",
""
],
[
"Engel",
"R.",
""
],
[
"Ranft",
"J.",
""
],
[
"Roesler",
"S.",
""
]
] |
0706.3871 | Patrick Treuthardt | P. Treuthardt, R. Buta, H. Salo, and E. Laurikainen | The Kinematically Measured Pattern Speeds of NGC 2523 and NGC 4245 | Accepted for publication in The Astronomical Journal, 11 figures, 2
tables | Astron.J.134:1195-1205,2007 | 10.1086/521149 | null | astro-ph | null | We have applied the Tremaine-Weinberg continuity equation method to derive
the bar pattern speed in the SB(r)b galaxy NGC 2523 and the SB(r)0/a galaxy NGC
4245 using the Calcium Triplet absorption lines. These galaxies were selected
because they have strong inner rings which can be used as independent tracers
of the pattern speed. The pattern speed of NGC 2523 is 26.4 $\pm$ 6.1 km
s$^{-1}$ kpc$^{-1}$, assuming an inclination of 49.7$^{\circ}$ and a distance
of 51.0 Mpc. The pattern speed of NGC 4245 is 75.5 $\pm$ 31.3 km s$^{-1}$
kpc$^{-1}$, assuming an inclination of 35.4$^{\circ}$ and a distance of 12.6
Mpc. The ratio of the corotation radius to the bar radius of NGC 2523 and NGC
4245 is 1.4 $\pm$ 0.3 and 1.1 $\pm$ 0.5, respectively. These values place the
bright inner rings near and slightly inside the corotation radius, as predicted
by barred galaxy theory. Within the uncertainties, both galaxies are found to
have fast bars that likely indicate dark halos of low central concentration.
The photometric properties, bar strengths, and disk stabilities of both
galaxies are also discussed.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:48:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Treuthardt",
"P.",
""
],
[
"Buta",
"R.",
""
],
[
"Salo",
"H.",
""
],
[
"Laurikainen",
"E.",
""
]
] |
0706.3872 | Chaz Schlindwein | Chaz Schlindwein | Understanding preservation theorems: Chapter VI of Proper and Improper
Forcing | null | null | null | null | math.LO | null | This expository paper covers the first two sections of chapter VI of Shelah's
book "Proper and Improper Forcing," including the preservationn (using CS
iterations of proper forcings) of omega-omega bounding, Sacks property, Lavewr
property, P-point property, and others.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:49:02 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Schlindwein",
"Chaz",
""
]
] |
0706.3873 | Pietro Slavich | A. Delgado, G.F. Giudice, P. Slavich | Dynamical mu Term in Gauge Mediation | 24 pages, 3 figures. v2: reference added, version to appear in
Phys.Lett.B | Phys.Lett.B653:424-433,2007 | 10.1016/j.physletb.2007.07.057 | CERN-PH-TH/2007-089, LAPTH-1200/07 | hep-ph | null | We address the mu problem of gauge mediation by considering a singlet chiral
superfield coupled to the Higgs and messenger fields. We compute the soft terms
generated below the messenger scale and study the phenomenological consequences
of the model. The experimental bound on the Higgs mass provides a severe
constraint that identifies three special regions of parameters where the mass
spectrum and the collider signatures can be distinct from ordinary gauge
mediation.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:57:57 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 15:47:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Delgado",
"A.",
""
],
[
"Giudice",
"G. F.",
""
],
[
"Slavich",
"P.",
""
]
] |
0706.3874 | Enrique Pardo | G. Abrams, P. N. \'Anh, A. Louly, E. Pardo | The classification question for Leavitt path algebras | Small changes and improvements of previous version | null | null | null | math.RA math.OA | null | We prove an algebraic version of the Gauge-Invariant Uniqueness Theorem, a
result which gives information about the injectivity of certain homomorphisms
between ${\mathbb Z}$-graded algebras. As our main application of this theorem,
we obtain isomorphisms between the Leavitt path algebras of specified graphs.
From these isomorphisms we are able to achieve two ends. First, we show that
the $K_0$ groups of various sets of purely infinite simple Leavitt path
algebras, together with the position of the identity element in $K_0$,
classifies the algebras in these sets up to isomorphism. Second, we show that
the isomorphism between matrix rings over the classical Leavitt algebras,
established previously using number-theoretic methods, can be reobtained via
appropriate isomorphisms between Leavitt path algebras.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 16:52:45 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Dec 2007 16:11:02 GMT"
},
{
"version": "v3",
"created": "Mon, 4 Feb 2008 07:31:36 GMT"
}
] | 2008-02-04T00:00:00 | [
[
"Abrams",
"G.",
""
],
[
"Ánh",
"P. N.",
""
],
[
"Louly",
"A.",
""
],
[
"Pardo",
"E.",
""
]
] |
0706.3875 | Fritz W. Bopp | J.Ranft, F.W.Bopp, R.Engel and S.Roesler | Inclusive distributions at the LHC as predicted from the DPMJET-III
model with chain fusion | Presented at "Heavy Ion Collisions at the LHC: last call for
predictions", Geneva Switzerland, May 14th-June 8th | null | null | SI-HEP-2007-10 | hep-ph | null | DPMJET-III with chain fusion is used to calculate inclusive distributions of
Pb-Pb collisions at LHC energies. We present rapidity distributions as well as
scaled multiplicities at mid-rapidity as function of the collision energy and
the number of participants.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:01:09 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Ranft",
"J.",
""
],
[
"Bopp",
"F. W.",
""
],
[
"Engel",
"R.",
""
],
[
"Roesler",
"S.",
""
]
] |
0706.3876 | Ranjani Viswanatha | Ranjani Viswanatha, Pralay K. Santra, Chandan Dasgupta and D. D. Sarma | Growth mechanism of nanocrystals in solution: ZnO, a case study | 10 pages, 4 figures | Phys. Rev. Lett., 98, 255501 (2007) | 10.1103/PhysRevLett.98.255501 | null | cond-mat.mtrl-sci | null | We investigate the mechanism of growth of nanocrystals from solution using
the case of ZnO. Spanning a wide range of values of the parameters, such as the
temperature and the reactant concentration, that control the growth, our
results establish a qualitative departure from the widely accepted diffusion
controlled coarsening (Ostwald ripening) process quantified in terms of the
Lifshitz-Slyozov-Wagner theory. Further, we show that these experimental
observations can be qualitatively and quantitatively understood within a growth
mechanism that is intermediate between the two well-defined limits of diffusion
control and kinetic control.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:01:25 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Viswanatha",
"Ranjani",
""
],
[
"Santra",
"Pralay K.",
""
],
[
"Dasgupta",
"Chandan",
""
],
[
"Sarma",
"D. D.",
""
]
] |
0706.3877 | Mladen Georgiev | O. Ivanov, Eugene Leyarovski, V. Lovchinov, Chr. Popov, M. Kamenova,
and M. Georgiev | Photoinduced electrification of solids. III. Temperature dependences | 10 pages of wording plus 14 figures, all pdf format | null | null | null | cond-mat.mtrl-sci | null | Two preceding parts of a paper (cond-mat/0508457, cond-mat/0508460)
considered the heuristic values of recent experiments pointing to the nearly
universal occurrence of photovoltages across solid surfaces under short-circuit
conditions. These voltages arise by virtue of a variety of spectrally-dependent
mechanisms activated by incident photons. For the visible range, the
photovoltages are obliged to the photodetachment of ions which leave the
surface charged. In an attempt to learn more, we now study short-circuit
photovoltages in well-defined materials including high-Tc superconductors
within a broad temperature range down to liquid nitrogen. We believe our data
provide a new insight into the process.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:14:40 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Ivanov",
"O.",
""
],
[
"Leyarovski",
"Eugene",
""
],
[
"Lovchinov",
"V.",
""
],
[
"Popov",
"Chr.",
""
],
[
"Kamenova",
"M.",
""
],
[
"Georgiev",
"M.",
""
]
] |
0706.3878 | Michael E. Wall | Dengming Ming (1), Marian Anghel (1), Michael E. Wall (1) ((1) Los
Alamos National Laboratory) | Hidden Structure in Protein Energy Landscapes | 11 pages, 4 figures; corrected citation of Ref. 10 | null | 10.1103/PhysRevE.77.021902 | LA-UR-07-1934 | q-bio.BM | null | Inherent structure theory is used to discover strong connections between
simple characteristics of protein structure and the energy landscape of a Go
model. The potential energies and vibrational free energies of inherent
structures are highly correlated, and both reflect simple measures of networks
of native contacts. These connections have important consequences for models of
protein dynamics and thermodynamics.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:32:38 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 14:49:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ming",
"Dengming",
""
],
[
"Anghel",
"Marian",
""
],
[
"Wall",
"Michael E.",
""
]
] |
0706.3879 | Alexey Gorshkov | Alexey V. Gorshkov, Liang Jiang, Markus Greiner, Peter Zoller, and
Mikhail D. Lukin | Coherent Quantum Optical Control with Subwavelength Resolution | 4 pages, 2 figures. V2: changes in presentation (text, figures,
tables) and new references - final version as published in Phys. Rev. Lett. | Phys. Rev. Lett. 100, 093005 (2008) | 10.1103/PhysRevLett.100.093005 | null | quant-ph cond-mat.mes-hall cond-mat.other | null | We suggest a new method for quantum optical control with nanoscale
resolution. Our method allows for coherent far-field manipulation of individual
quantum systems with spatial selectivity that is not limited by the wavelength
of radiation and can, in principle, approach a few nanometers. The selectivity
is enabled by the nonlinear atomic response, under the conditions of
Electromagnetically Induced Transparency, to a control beam with intensity
vanishing at a certain location. Practical performance of this technique and
its potential applications to quantum information science with cold atoms,
ions, and solid-state qubits are discussed.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:46:11 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Mar 2008 03:22:38 GMT"
}
] | 2008-03-10T00:00:00 | [
[
"Gorshkov",
"Alexey V.",
""
],
[
"Jiang",
"Liang",
""
],
[
"Greiner",
"Markus",
""
],
[
"Zoller",
"Peter",
""
],
[
"Lukin",
"Mikhail D.",
""
]
] |
0706.3880 | James Bagrow | James P. Bagrow | Evaluating Local Community Methods in Networks | 8 pages, 9 figures, code included with source | J. Stat. Mech. (2008) P05001 | 10.1088/1742-5468/2008/05/P05001 | null | physics.data-an physics.soc-ph | null | We present a new benchmarking procedure that is unambiguous and specific to
local community-finding methods, allowing one to compare the accuracy of
various methods. We apply this to new and existing algorithms. A simple class
of synthetic benchmark networks is also developed, capable of testing
properties specific to these local methods.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:11:25 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Nov 2007 16:46:58 GMT"
}
] | 2008-08-05T00:00:00 | [
[
"Bagrow",
"James P.",
""
]
] |
0706.3881 | Sebastian Heinz | S. Heinz, N. S. Schulz, W. N. Brandt, and D. K. Galloway | Evidence for a parsec scale X-ray jet from the accreting neutron star
Circinus X-1 | Added journal reference, corrected on reference and typo in labels
for Fig. 1; 5 pages, 3 figures, ApJ Letter, in press | null | 10.1086/519950 | null | astro-ph | null | We analyzed the zero-order image of a 50 ks Chandra gratings observation of
Circinus X-1, taken in 2005 during the source's low-flux state. Circinus X-1 is
an accreting neutron star that exhibits ultra-relativistic arcsecond-scale
radio jets and diffuse arcminute-scale radio jets and lobes. The image shows a
clear excess along the general direction of the north-western counter-jet,
coincident with the radio emission, suggesting that it originates either in the
jet itself or in the shock the jet is driving into its environment. This makes
Circinus X-1 the first neutron star for which an extended X-ray jet has been
detected. The kinetic jet power we infer is significantly larger than the
minimum power required for the jet to inflate the large scale radio nebula.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:48:45 GMT"
},
{
"version": "v2",
"created": "Fri, 29 Jun 2007 19:28:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Heinz",
"S.",
""
],
[
"Schulz",
"N. S.",
""
],
[
"Brandt",
"W. N.",
""
],
[
"Galloway",
"D. K.",
""
]
] |
0706.3882 | Fl\'avio da Silveira Alexandre | F. A. Silveira and F. D. A. Aar\~ao Reis | Surface and Bulk Properties of Deposits Grown with a Bidisperse
Ballistic Deposition Model | 18 pages, 8 figures, to be published in Physical Review E | null | 10.1103/PhysRevE.75.061608 | null | cond-mat.stat-mech cond-mat.soft | null | We study roughness scaling of the outer surface and the internal porous
structure of deposits generated with the three-dimensional bidisperse ballistic
deposition (BBD), in which particles of two sizes are randomly deposited.
Systematic extrapolation of roughness and dynamical exponents and the
comparison of roughness distributions indicate that the top surface has
Kardar-Parisi-Zhang scaling for any ratio F of the flux between large and small
particles. A scaling theory predicts the characteristic time of the crossover
from random to correlated growth in BBD and provides relations between the
amplitudes of roughness scaling and F in the KPZ regime. The porosity of the
deposits monotonically increases with F and scales as F^{1/2} for small F,
which is also explained by the scaling approach and illustrates the possibility
of connecting surface growth rules and bulk properties. The suppression of
relaxation mechanisms in BBD enhances the connectivity of the deposits when
compared to other ballisticlike models, so that they percolate down to F~0.05.
The fractal dimension of the internal surface of the percolating deposits is
D_F~2.9, which is very close to the values in other ballisticlike models and
suggests universality among these systems.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 17:59:23 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 15:32:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Silveira",
"F. A.",
""
],
[
"Reis",
"F. D. A. Aarão",
""
]
] |
0706.3883 | Pablo Fern\'andez | Pablo Fern\'andez and Albrecht Ott | Single cell mechanics: stress stiffening and kinematic hardening | 4 pages, 6 figures | null | 10.1103/PhysRevLett.100.238102 | null | physics.bio-ph | null | Cell mechanical properties are fundamental to the organism but remain poorly
understood. We report a comprehensive phenomenological framework for the
nonlinear rheology of single fibroblast cells: a superposition of elastic
stiffening and viscoplastic kinematic hardening. Our results show, that in
spite of cell complexity its mechanical properties can be cast into simple,
well-defined rules, which provide mechanical cell strength and robustness via
control of crosslink slippage.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:07:23 GMT"
},
{
"version": "v2",
"created": "Tue, 30 Oct 2007 14:45:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fernández",
"Pablo",
""
],
[
"Ott",
"Albrecht",
""
]
] |
0706.3884 | Samir Mathur | Samir D. Mathur | Black hole size and phase space volumes | 37 pages, 6 figures, Latex | null | null | null | hep-th | null | For extremal black holes the fuzzball conjecture says that the throat of the
geometry ends in a quantum `fuzz', instead of being infinite in length with a
horizon at the end. For the D1-D5 system we consider a family of sub-ensembles
of states, and find that in each case the boundary area of the fuzzball
satisfies a Bekenstein type relation with the entropy enclosed. We suggest a
relation between the `capped throat' structure of microstate geometries and the
fact that the extremal hole was found to have zero entropy in some gravity
computations. We examine quantum corrections including string 1-loop effects
and check that they do not affect our leading order computations.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:07:23 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Mathur",
"Samir D.",
""
]
] |
0706.3885 | Joshua Thompson | The BABAR Collaboration: B. Aubert, et al | Measurements of CP-Violating Asymmetries in the Decay B0-->K+K-K0 | 7 pages, 4 postscript figures; minor edits to reflect published
version | Phys.Rev.Lett.99:161802,2007 | 10.1103/PhysRevLett.99.161802 | BABAR-PUB-07/029, SLAC-PUB-12625 | hep-ex | null | We analyze the decay B0 --> K+ K- K0 using 383 million B-Bbar events
collected by the BaBar detector at SLAC to extract CP violation parameter
values over the Dalitz plot. Combining all K+ K- K0 events, we find A_CP =
-0.015 +/- 0.077 +/- 0.053 and beta_eff = 0.352 +/- 0.076 +/- 0.026 rad,
corresponding to a CP violation significance of 4.8 sigma. A second solution
near pi/2 - beta_eff is disfavored with a significance of 4.5 sigma. We also
report A_CP and beta_eff separately for decays to phi(1020) K0, f0(980) K0, and
K+ K- K0 with m_{K+ K-} > 1.1 GeV/c^2.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:13:30 GMT"
},
{
"version": "v2",
"created": "Mon, 29 Oct 2007 22:42:24 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0706.3886 | Jun Hidaka | Jun Hidaka and George M. Fuller | Sterile Neutrino-Enhanced Supernova Explosions | 12 pages, 4 figures | Phys.Rev.D76:083516,2007 | 10.1103/PhysRevD.76.083516 | null | astro-ph hep-ph | null | We investigate the enhancement of lepton number, energy, and entropy
transport resulting from active-sterile neutrino conversion $\nu_e\to\nu_s$
deep in the post-bounce supernova core followed by re-conversion
$\nu_s\to\nu_e$ further out, near the neutrino sphere. We explicitly take
account of shock wave and neutrino heating modification of the active neutrino
forward scattering potential which governs sterile neutrino production. We find
that the $\nu_e$ luminosity at the neutrino sphere could be increased by
between $\sim 10 %$ and $\sim 100 %$ during the crucial shock re-heating epoch
if the sterile neutrino has a rest mass and vacuum mixing parameters in ranges
which include those required for viable sterile neutrino dark matter. We also
find sterile neutrino transport-enhanced entropy deposition ahead of the shock.
This `` pre-heating\rq\rq can help melt heavy nuclei and thereby reduce the
nuclear photo-dissociation burden on the shock. Both neutrino luminosity
enhancement and pre-heating could increase the likelihood of a successful core
collapse supernova explosion.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:16:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hidaka",
"Jun",
""
],
[
"Fuller",
"George M.",
""
]
] |
0706.3887 | Loison Hoi | Loison Hoi and James M. Cline | Testing for Features in the Primordial Power Spectrum | 23 pages, 6 figures; added new section on theoretical motivation for
k^3 term, and discussion of double D-term hybrid inflation models; title
changed, added a new section discussing the generic spikelike features,
published in IJMPD | Int.J.Mod.Phys.D18:1863,2009 | 10.1142/S0218271809015734 | null | astro-ph hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Well-known causality arguments show that events occurring during or at the
end of inflation, associated with reheating or preheating, could contribute a
blue component to the spectrum of primordial curvature perturbations, with the
dependence k^3. We explore the possibility that they could be observably large
in CMB, LSS, and Lyman-alpha data. We find that a k^3 component with a cutoff
at some maximum k can modestly improve the fits (Delta chi^2=2.0, 5.4) of the
low multipoles (l ~ 10 - 50) or the second peak (l ~ 540) of the CMB angular
spectrum when the three-year WMAP data are used. Moreover, the results from
WMAP are consistent with the CBI, ACBAR, 2dFGRS, and SDSS data when they are
included in the analysis. Including the SDSS galaxy clustering power spectrum,
we find weak positive evidence for the k^3 component at the level of Delta chi'
= 2.4, with the caveat that the nonlinear evolution of the power spectrum may
not be properly treated in the presence of the k^3 distortion. To investigate
the high-k regime, we use the Lyman-alpha forest data (LUQAS, Croft et al., and
SDSS Lyman-alpha); here we find evidence at the level Delta chi^2' = 3.8.
Considering that there are two additional free parameters in the model, the
above results do not give a strong evidence for features; however, they show
that surprisingly large bumps are not ruled out. We give constraints on the
ratio between the k^3 component and the nearly scale-invariant component, r_3 <
1.5, over the range of wave numbers 0.0023/Mpc < k < 8.2/Mpc. We also discuss
theoretical models which could lead to the k^3 effect, including ordinary
hybrid inflation and double D-term inflation models. We show that the
well-motivated k^3 component is also a good representative of the generic
spikelike feature in the primordial perturbation power spectrum.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 19:41:43 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Oct 2007 19:21:29 GMT"
},
{
"version": "v3",
"created": "Tue, 22 Dec 2009 22:26:19 GMT"
}
] | 2010-03-23T00:00:00 | [
[
"Hoi",
"Loison",
""
],
[
"Cline",
"James M.",
""
]
] |
0706.3888 | Matthias R. Schreiber | Matthias R. Schreiber, Jean-Pierre Lasota | The dwarf nova SS Cygni: what is wrong? | 6 pages, 3 figures, accepted for publication in Astronomy and
Astrophysics | null | 10.1051/0004-6361:20078146 | null | astro-ph | null | Since the Fine Guiding Sensor (FGS) on the Hubble Space Telescope (HST) was
used to measure the distance to SS Cyg to be $166\pm12$ pc, it became apparent
that at this distance the disc instability model fails to explain the absolute
magnitude during outburst. It remained, however, an open question whether the
model or the distance have to be revised. Recent observations led to a revision
of the system parameters of SS Cyg and seem to be consistent with a distance of
$d\gta 140$ pc. We re-discuss the problem taking into account the new binary
and stellar parameters measured for SS Cyg. We confront not only the
observations with the predictions of the disc instability model but also
compare SS Cyg with other dwarf novae and nova-like systems. We assume the disc
during outburst to be in a quasi stationary state and use the black-body
approximation to estimate the accretion rate during outburst as a function of
distance. Using published analysis of the long term light curve we determine
the mean mass transfer rate of SS Cyg as a function of distance and compare the
result with mass transfer rates derived for other dwarf novae and nova-like
systems. At a distance of $d\gta 140$ pc, both the accretion rate during
outburst as well as the mean mass transfer rate of SS Cyg contradict the disc
instability model. More important, at such distances we find the mean mass
transfer rate of SS Cyg to be higher or comparable to those derived for
nova-like systems. Our findings show that a distance to SS Cyg $\gta 140$ pc
contradicts the main concepts developed for accretion discs in cataclysmic
variables during the last 30 years. Either our current picture of disc
accretion in these systems must be revised or the distance to SS Cyg is $\sim
100$ pc
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:32:56 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 15:05:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Schreiber",
"Matthias R.",
""
],
[
"Lasota",
"Jean-Pierre",
""
]
] |
0706.3889 | Loic Vanel | St\'ephanie Deschanel (MATEIS), Lo\"ic Vanel (Phys-ENS), G\'erard
Vigier (MATEIS), Nathalie Godin (MATEIS), Sergio Ciliberto (Phys-ENS) | Statistical properties of microcracking in polyurethane foams under
tensile test, influence of temperature and density | null | International Journal of Fracture 1-4, 140 (07/2006) 87 | 10.1007/s10704-006-0051-1 | null | cond-mat.mtrl-sci physics.class-ph | null | We report tensile failure experiments on polyurethane (PU) foams. Experiments
have been performed by imposing a constant strain rate. We work on
heterogeneous materials for whom the failure does not occur suddenly and can
develop as a multistep process through a succession of microcracks that end at
pores. The acoustic energy and the waiting times between acoustic events follow
power-law distributions. This remains true while the foam density is varied.
However, experiments at low temperatures (PU foams more brittle) have not
yielded power-laws for the waiting times. The cumulative acoustic energy has no
power law divergence at the proximity of the failure point which is
qualitatively in agreement with other experiments done at imposed strain. We
notice a plateau in cumulative acoustic energy that seems to occur when a
single crack starts to propagate.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:33:51 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Deschanel",
"Stéphanie",
"",
"MATEIS"
],
[
"Vanel",
"Loïc",
"",
"Phys-ENS"
],
[
"Vigier",
"Gérard",
"",
"MATEIS"
],
[
"Godin",
"Nathalie",
"",
"MATEIS"
],
[
"Ciliberto",
"Sergio",
"",
"Phys-ENS"
]
] |
0706.3890 | M Hossain Ali | M. Hossain Ali | Hawking Radiation via Tunneling from Hot NUT-Kerr-Newman-Kasuya
Spacetime | To appear in Class. Quant. Grav | Class.Quant.Grav.24:5849-5860,2007 | 10.1088/0264-9381/24/23/008 | null | gr-qc hep-th | null | We study the Hawking thermal spectrum in dragging coordinate system and the
tunneling radiation characteristics of hot NUT-Kerr-Newman-Kasuya spacetime.
The tunneling rates at the event and cosmological horizon are found to be
related to the change of Bekenstein-Hawking entropy. The radiation spectrum is
not pure thermal and thus there is a correction to the Hawking thermal
spectrum.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:54:45 GMT"
},
{
"version": "v2",
"created": "Sun, 28 Oct 2007 05:33:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ali",
"M. Hossain",
""
]
] |
0706.3891 | Angelo Loinger | Angelo Loinger, Tiziana Marsico | On spherically symmetric structures in GR | 10 pages, 1 figure, typing correction at page 8 | null | null | null | physics.gen-ph | null | We reconsider some subtle points concerning the relativistic treatment of the
gravitational fields generated by spherically symmetric structures.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:50:29 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 17:59:26 GMT"
},
{
"version": "v3",
"created": "Mon, 16 Jul 2007 19:49:42 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Loinger",
"Angelo",
""
],
[
"Marsico",
"Tiziana",
""
]
] |
0706.3892 | Timothy Andersen | T. D. Andersen and C. C. Lim | Negative Specific Heat in a Quasi-2D Generalized Vorticity Model | 12 pages, 3 figures; updated with revisions | null | 10.1103/PhysRevLett.99.165001 | null | cond-mat.stat-mech | null | Negative specific heat is a dramatic phenomenon where processes decrease in
temperature when adding energy. It has been observed in gravo-thermal collapse
of globular clusters. We now report finding this phenomenon in bundles of
nearly parallel, periodic, single-sign generalized vortex filaments in the
electron magnetohydrodynamic (EMH) model for the unbounded plane under strong
magnetic confinement. We derive the specific heat using a steepest descent
method and a mean field property. Our derivations show that as temperature
increases, the overall size of the system increases exponentially and the
energy drops. The implication of negative specific heat is a runaway reaction,
resulting in a collapsing inner core surrounded by an expanding halo of
filaments.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 19:10:48 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Sep 2007 19:37:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Andersen",
"T. D.",
""
],
[
"Lim",
"C. C.",
""
]
] |
0706.3893 | James G. Smith | The BABAR Collaboration: B. Aubert et al | Branching fraction and CP-violation charge asymmetry measurements for
B-meson decays to eta K+-, etapi+-, eta'K, eta'pi+-, omega K, and omegapi+- | As published in PRD RC; some numbers slightly changed | Phys.Rev.D76:031103,2007 | 10.1103/PhysRevD.76.031103 | BABAR-PUB-07/032, SLAC-PUB-12630 | hep-ex | null | We present measurements of the branching fractions for B0 meson decays to
eta'K0 and omegaK0, and of the branching fractions and CP-violation charge
asymmetries for B+ meson decays to etapi+, etaK+, eta'pi+, eta'K+, omegapi+,
and omegaK+. The data, collected with the BABAR detector at the Stanford Linear
Accelerator Center, represent 383 million BBbar pairs produced in e+e-
annihilation. The measurements agree with previous results; we find no evidence
for direct CP violation.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 19:55:35 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 22:48:13 GMT"
},
{
"version": "v3",
"created": "Tue, 28 Aug 2007 19:52:23 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"al",
"B. Aubert et",
""
]
] |
0706.3894 | Jasonjot Singh Kalirai | Jasonjot S. Kalirai, Brad M. S. Hansen, Daniel D. Kelson, David B.
Reitzel, R. Michael Rich, and Harvey B. Richer | The Initial-Final Mass Relation: Direct Constraints at the Low Mass End | 18 pages, 12 figures, 3 tables. Submitted to Astrophys. J. Revised
from first version | Astrophys.J. 676 (2008) 594 | 10.1086/527028 | null | astro-ph | null | The initial-final mass relation represents a mapping between the mass of a
white dwarf remnant and the mass that the hydrogen burning main-sequence star
that created it once had. The relation thus far has been constrained using a
sample of ~40 stars in young open clusters, ranging in initial mass from ~2.75
-- 7 Msun, and shows a general trend that connects higher mass main-sequence
stars with higher mass white dwarfs. In this paper, we present CFHT/CFH12K
photometric and Keck/LRIS multiobject spectroscopic observations of a sample of
22 white dwarfs in two older open clusters, NGC 7789 (t = 1.4 Gyr) and NGC 6819
(t = 2.5 Gyr). We measure masses for the highest S/N spectra by fitting the
Balmer lines to atmosphere models and place the first direct constraints on the
low mass end of the initial-final mass relation. Our results indicate that the
observed general trend at higher masses continues down to low masses, with
M_initial = 1.16 Msun main-sequence stars forming M_final = 0.53 Msun white
dwarfs (including our data from the very old open cluster, NGC 6791). This
extention of the relation represents a four fold increase in the total number
of hydrogen burning stars for which the integrated mass loss can now be
calculated, assuming a Salpeter initial mass function. The new leverage at the
low mass end is used to derive a purely empirical initial-final mass relation
without the need for any indirectly derived anchor points. The sample of white
dwarfs in these clusters also shows several very interesting systems that we
discuss further: a DB (helium atmosphere) white dwarf, a magnetic white dwarf,
a DAB (mixed hydrogen/helium atmosphere or a double degenerate DA+DB) white
dwarf(s), and two possible equal mass DA double degenerate binary systems.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 08:09:13 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2007 17:49:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kalirai",
"Jasonjot S.",
""
],
[
"Hansen",
"Brad M. S.",
""
],
[
"Kelson",
"Daniel D.",
""
],
[
"Reitzel",
"David B.",
""
],
[
"Rich",
"R. Michael",
""
],
[
"Richer",
"Harvey B.",
""
]
] |
0706.3895 | Isaac Shlosman | Clayton Heller (GSU), Isaac Shlosman (UK Lexington) and Lia
Athanassoula (Observatoire de Marseille) | Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks,
Bulges and Bars | 18 pages, 16 figures, accepted by the Astrophysical Journal. Minor
revisions. The high-resolution figures can be found at
http://www.pa.uky.edu/~shlosman/research/galdyn/figs07a/ | null | 10.1086/523260 | null | astro-ph | null | We investigate the formation and evolution of galactic disks immersed in
assembling live DM halos. Disk/halo components have been evolved from the
cosmological initial conditions and represent the collapse of an isolated
density perturbation. The baryons include gas (which participates in star
formation [SF]) and stars. The feedback from the stellar energy release onto
the ISM has been implemented. We find that (1) The growing triaxial halo figure
tumbling is insignificant and the angular momentum (J) is channeled into the
internal circulation; (2) Density response of the disk is out of phase with the
DM, thus diluting the inner halo flatness and washing out its prolateness; (3)
The total J is neathly conserved, even in models accounting for feedback; (4)
The specific J for the DM is nearly constant, while that for baryons is
decreasing; (5) Early stage of disk formation resembles the cat's cradle -- a
small amorphous disk fueled via radial string patterns; (6) The initially
puffed up gas component in the disk thins when the SF rate drops below ~5
Mo/yr; (7) About 40%-60% of the baryons remain outside the SF region; (8)
Rotation curves appear to be flat and account for the observed disk/halo
contributions; (9) A range of bulge-dominated to bulgeless disks was obtained;
Lower density threshold for SF leads to a smaller, thicker disk; Gravitational
softening in the gas has a substantial effect on various aspects of galaxy
evolution and mimics a number of intrinsic processes within the ISM; (10) The
models are characterized by an extensive bar-forming activity; (11) Nuclear
bars, dynamically coupled and decoupled form in response to the gas inflow
along the primary bars.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:00:17 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 19:23:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Heller",
"Clayton",
"",
"GSU"
],
[
"Shlosman",
"Isaac",
"",
"UK Lexington"
],
[
"Athanassoula",
"Lia",
"",
"Observatoire de Marseille"
]
] |
0706.3896 | Ruth Lazkoz | Mariam Bouhmadi-L\'opez and Ruth Lazkoz | Chaplygin DGP cosmologies | 8 pages, 4 figures, revtex | Phys.Lett.B654:51-57,2007 | 10.1016/j.physletb.2007.07.063 | null | astro-ph | null | A new class of braneworld models displaying late-time phantom acceleration
without resorting to a phantom fluid is presented. In this scenario expansion
is fuelled by dark matter together with some effective dark energy capable of
crossing the phantom divide. Unlike a previous proposal of this nature, in
these models the effective phantom behaviour remains valid at all redshifts for
some choices of the free parameters of the models. The construction is based on
the generalised Chaplygin gas, and the cosmological history interpolates
between a standard CDM-like behaviour at early times and a de Sitter-like
behaviour at late times, so no future singularity is reached.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:01:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bouhmadi-López",
"Mariam",
""
],
[
"Lazkoz",
"Ruth",
""
]
] |
0706.3897 | Mariana Kirchbach | A. P. Raposo, H. J. Weber, D. Alvarez-Castillo, M. Kirchbach | Romanovski polynomials in selected physics problems | RevTex, 38 pages, 2 figures, review | Central European Journal of Physics, 5(3), 2007, pp. 253-284 | 10.2478/s11534-007-0018-5 | null | quant-ph nucl-th | null | We briefly review the five possible real polynomial solutions of
hypergeometric differential equations. Three of them are the well known
classical orthogonal polynomials, but the other two are different with respect
to their orthogonality properties. We then focus on the family of polynomials
which exhibits a finite orthogonality. This family, to be referred to as the
Romanovski polynomials, is required in exact solutions of several physics
problems ranging from quantum mechanics and quark physics to random matrix
theory. It appears timely to draw attention to it by the present study. Our
survey also includes several new observations on the orthogonality properties
of the Romanovski polynomials and new developments from their Rodrigues
formula.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:03:27 GMT"
}
] | 2007-07-02T00:00:00 | [
[
"Raposo",
"A. P.",
""
],
[
"Weber",
"H. J.",
""
],
[
"Alvarez-Castillo",
"D.",
""
],
[
"Kirchbach",
"M.",
""
]
] |
0706.3898 | Pran Nath | Haim Goldberg and Pran Nath | Scalar modifications to gravity from unparticle effects may be testable | 10 pages and 1 figure. Accepted for publication in Physical Review
Letters. Title changed in the revised version. Original title "Ungravity and
its possible test" | Phys.Rev.Lett.100:031803,2008 | 10.1103/PhysRevLett.100.031803 | null | hep-ph gr-qc hep-th | null | Interest has focussed recently on low energy implications of a nontrivial
scale invariant sector of an effective field theory with an IR fixed point,
manifest in terms of ``unparticles'' with peculiar properties. If unparticle
stuff exists it could couple to the stress tensor and mediate a new 'fifth'
force which we call 'ungravity' arising from the exchange of unparticles
between massive particles, which in turn could modify the inverse square law.
Under the assumption of strict conformal invariance in the hidden sector down
to low energies, we compute the lowest order ungravity correction to the
Newtonian gravitational potential and find scale invariant power law
corrections of type $(R_{G}/r)^{2d_{\cal U} -1}$ where $d_{\cal U}$ is an
anomalous unparticle dimension and $R_{G}$ is a characteristic length scale
where the ungravity interactions become significant. $d_{\cal U}$ is
constrained to lie the range $ d_{\cal U} > 3 (2)$ for a spin 2 (spin 0)
unparticle coupling to the stress tensor (and its trace) and leads to
modification of the inverse square law with $r$ dependence in the range between
$1/r^{4+2\delta} (\delta>0)$, while extra dimension models with warping modify
the force law with corrections beginning with terms O$(1/r^3)$ for small $r$
but exponentially suppressed for large $r$. Thus a discrimination between extra
dimension models and ungravity is possible in future improved submillimeter
tests of gravity.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 19:15:44 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jul 2007 16:21:36 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Dec 2007 21:36:05 GMT"
}
] | 2008-12-30T00:00:00 | [
[
"Goldberg",
"Haim",
""
],
[
"Nath",
"Pran",
""
]
] |
0706.3899 | Martin Sieber | Martin Sieber | Wavefunctions, Green's functions and expectation values in terms of
spectral determinants | 18 pages, no figures | Nonlinearity 20 (2007) 2721 | 10.1088/0951-7715/20/11/013 | null | nlin.CD math-ph math.MP | null | We derive semiclassical approximations for wavefunctions, Green's functions
and expectation values for classically chaotic quantum systems. Our method
consists of applying singular and regular perturbations to quantum
Hamiltonians. The wavefunctions, Green's functions and expectation values of
the unperturbed Hamiltonian are expressed in terms of the spectral determinant
of the perturbed Hamiltonian. Semiclassical resummation methods for spectral
determinants are applied and yield approximations in terms of a finite number
of classical trajectories. The final formulas have a simple form. In contrast
to Poincare surface of section methods, the resummation is done in terms of the
periods of the trajectories.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 19:41:20 GMT"
}
] | 2010-03-09T00:00:00 | [
[
"Sieber",
"Martin",
""
]
] |
0706.3900 | Marta Volonteri | Marta Volonteri, Marek Sikora, Jean-Pierre Lasota | Black-Hole Spin and Galactic Morphology | Accepted for publication in the Astrophysical Journal | null | 10.1086/521186 | NSF-KITP-07-147 | astro-ph | null | We investigate the conjecture by Sikora, Stawarz & Lasota (2007) that the
observed AGN--radio-loudness bimodality can be explained by the
morphology-related bimodality of black-hole spin distribution in the centers of
galaxies: central black holes in giant elliptical galaxies may have (on
average) much larger spins than black holes in spiral/disc galaxies. We study
how accretion from a warped disc influences the evolution of black hole spins
and conclude that within the cosmological framework, where the most massive BHs
have grown in mass via merger driven accretion, one indeed expects most
supermassive black holes in elliptical galaxies to have on average higher spin
than black holes in spiral galaxies, where random, small accretion episodes
(e.g. tidally disrupted stars, accretion of molecular clouds) might have played
a more important role.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 13:31:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Volonteri",
"Marta",
""
],
[
"Sikora",
"Marek",
""
],
[
"Lasota",
"Jean-Pierre",
""
]
] |
0706.3901 | Gregory J. Herczeg | Gregory J. Herczeg, Joan Najita, Lynne A. Hillenbrand, Ilaria Pascucci | High-resolution Spectroscopy of [Ne II] Emission from TW Hya | Accepted by ApJ. 18 pages, including 2 figures and 2 tables | null | 10.1086/521545 | null | astro-ph | null | We present high-resolution echelle spectra of [Ne II] 12.81 micron emission
from the classical T Tauri star (CTTS) TW Hya obtained with MICHELLE on Gemini
North. The line is centered at the stellar radial velocity and has an intrinsic
FWHM of 21\pm 4 km/s. The line width is broader than other narrow emission
lines typically associated with the disk around TW Hya. If formed in a disk,
the line broadening could result from turbulence in a warm disk atmosphere,
Keplerian rotation at an average distance of 0.1 AU from the star, or a
photoevaporative flow from the optically-thin region of the disk. We place
upper limits on the [Ne II] emission flux from the CTTSs DP Tau and BP Tau.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:12:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Herczeg",
"Gregory J.",
""
],
[
"Najita",
"Joan",
""
],
[
"Hillenbrand",
"Lynne A.",
""
],
[
"Pascucci",
"Ilaria",
""
]
] |
0706.3902 | Jesus Martinez-Linares | Jesus Martinez-Linares | Hierarchy of inequalities for quantitative duality | 7 pages, 4 figures | Physical Review A75, 052112 (2007) | 10.1103/PhysRevA.75.052112 | null | quant-ph | null | We derive different relations quantifying duality in a generic two-way
interferometer. These relations set different upper bounds to the visibility V
of the fringes measured at the output port of the interferometer. A hierarchy
of inequalities is presented which exhibits the influence of the availability
to the experimenter of different sources of which-way information contributing
to the total distinguishability D of the ways. For mixed states and unbalanced
interferometers an inequality is derived, V^2+ Xi^2 \leq 1, which can be more
stringent than the one associated with the distinguishability (V^2+ D^2 \leq
1).
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:13:22 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Martinez-Linares",
"Jesus",
""
]
] |
0706.3903 | Justin Khoury | Evgeny I. Buchbinder, Justin Khoury, Burt A. Ovrut | On the Initial Conditions in New Ekpyrotic Cosmology | 54 pages, 9 figures. v2: typos corrected | JHEP0711:076,2007 | 10.1088/1126-6708/2007/11/076 | null | hep-th astro-ph hep-ph | null | New Ekpyrotic Cosmology is an alternative scenario of early universe
cosmology in which the universe existed before the big bang. The simplest model
relies on two scalar fields, whose entropy perturbation leads to a
scale-invariant spectrum of density fluctuations. The ekpyrotic solution has a
tachyonic instability along the entropy field direction which, a priori,
appears to require fine-tuning of the initial conditions. In this paper, we
show that these can be achieved naturally by adding a small positive mass term
for the tachyonic field and coupling to light fermions. Then, for a wide range
of initial conditions, the tachyonic field gets stabilized with the appropriate
values well before the onset of the ekpyrotic phase. Furthermore, we show that
ekpyrotic theory is successful in solving the flatness, horizon and homogeneity
problems of standard big bang cosmology. Motivated by the analysis of the
tachyonic instability, we propose a simplification of the model in terms of new
field variables. Instead of requiring two exponential potentials, one for each
scalar field, it suffices to consider a single nearly exponential potential for
one of the fields and a tachyonic mass term along the orthogonal direction in
field space. All other terms in the potential are essentially arbitrary. This
greatly widens the class of ekpyrotic potentials and allows substantial freedom
in determining the spectral index and possible non-Gaussianity. We present a
generalized expression for the spectral index which is easily consistent with
the observed red tilt. We also argue that for a wide range of potentials
non-Gaussianity can be substantial, within the reach of current observations.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:14:56 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 21:40:26 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Buchbinder",
"Evgeny I.",
""
],
[
"Khoury",
"Justin",
""
],
[
"Ovrut",
"Burt A.",
""
]
] |
0706.3904 | Clara L\"oh | Clara Loeh and Roman Sauer | Simplicial volume of Hilbert modular varieties | 11 pages; rearrangement of section and minor changes; final version;
to appear in Commentarii Mathematici Helvetici | null | null | null | math.GT math.DG | null | The simplicial volume introduced by Gromov provides a topologically
accessible lower bound for the minimal volume. Lafont and Schmidt proved that
the simplicial volume of closed, locally symmetric spaces of non-compact type
is positive. In this paper, we present a generalization of this result to
certain non-compact locally symmetric spaces of finite volume, to so-called
Hilbert modular varieties. The key idea is to reduce the problem to the compact
case by first relating the simplicial volume of these manifolds to the
Lipschitz simplicial volume and then taking advantage of a proportionality
principle for the Lipschitz simplicial volume. Moreover, using computations of
Bucher-Karlsson for the simplicial volume of products of closed surfaces, we
obtain the exact value of the simplicial volume of Hilbert modular surfaces.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:16:53 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 03:17:02 GMT"
},
{
"version": "v3",
"created": "Tue, 6 Nov 2007 17:11:47 GMT"
}
] | 2007-11-06T00:00:00 | [
[
"Loeh",
"Clara",
""
],
[
"Sauer",
"Roman",
""
]
] |
0706.3905 | Carlos Gutierrez | Carlos Biasi, Carlos Gutierrez and Edivaldo L. dos Santos | The Implicit Function Theorem for continuous functions | 9 pages, no figures | null | null | null | math.AT math.CA | null | In the present paper we obtain a new homological version of the implicit
function theorem and some versions of the Darboux theorem. Such results are
proved for continuous maps on topological manifolds. As a consequence, some
versions of these classic theorems are proved when we consider differenciable
(not necessarily C^1) maps.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:19:59 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Biasi",
"Carlos",
""
],
[
"Gutierrez",
"Carlos",
""
],
[
"Santos",
"Edivaldo L. dos",
""
]
] |
0706.3906 | Oren Raz | O. Raz, J.E. Avron | A Comment on "Optimal Stroke Patterns for Purcell's Three-Link Swimmer" | 3 page, 1 figure | Phys. Rev. Lett. 100, 029801 (2008) | 10.1103/PhysRevLett.100.029801 | null | physics.flu-dyn | null | For large enough aspect ratio, we find better stroke patterns then the
patterns proposed by D. Tam and A.P.Hosoi in their letter to PRL "Optimal
Stroke Patterns for Purcell's Three-Link Swimmer".
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 19:08:41 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 07:03:18 GMT"
}
] | 2010-07-28T00:00:00 | [
[
"Raz",
"O.",
""
],
[
"Avron",
"J. E.",
""
]
] |
0706.3907 | Dam Thanh Son | Rudro R. Biswas, Subir Sachdev, Dam T. Son | Coulomb impurity in graphene | 10 pages, 3 figures; (v2) Corrected sign error in Eq. (13); (v3)
corrected figures | Phys.Rev. B76 (2007) 205122 | 10.1103/PhysRevB.76.205122 | INT-PUB 07-17 | cond-mat.str-el hep-th | null | We consider the problem of screening of an electrically charged impurity in a
clean graphene sheet. When electron-electron interactions are neglected, the
screening charge has a sign opposite to that of the impurity, and is localized
near the impurity. Interactions between electrons smear out the induced charge
density to give a large-distance tail that follows approximately, but not
exactly, an r^{-2} behavior and with a sign which is the same as that of the
impurity.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:43:55 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 07:50:56 GMT"
},
{
"version": "v3",
"created": "Thu, 29 Nov 2007 02:13:33 GMT"
}
] | 2007-11-29T00:00:00 | [
[
"Biswas",
"Rudro R.",
""
],
[
"Sachdev",
"Subir",
""
],
[
"Son",
"Dam T.",
""
]
] |
0706.3908 | Lyman Page | S. Lange and L. Page | Measuring the Expansion of the Universe Through Changes in the CMB
Photosphere | 4 pages, 8 figures, submitted to ApJ | null | 10.1086/523097 | null | astro-ph | null | The expansion of the universe may be observed in ``realtime'' by measuring
changes in the patterns of the anisotropy in the CMB. As the universe ages, the
surface of decoupling--or the CMB photosphere--moves away from us and samples a
different gravitational landscape. The response of the CMB to this new
landscape results in a different pattern than we observe today. The largest
change occurs at l~900. We show that with an array of detectors that we may
envision having in a couple of decades, one can in principle measure the change
in the anisotropy with two high precision measurements separated by a century.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:53:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lange",
"S.",
""
],
[
"Page",
"L.",
""
]
] |
0706.3909 | Olga Mena Requejo | Olga Mena (INFN, Rome; Rome U.), Sergio Palomares-Ruiz and Silvia
Pascoli (Durham U., IPPP) | Reconstructing WIMP properties with neutrino detectors | 4 pp, 2 figs; revised version accepted for publication with further
discussions and references | Phys.Lett.B664:92-96,2008 | 10.1016/j.physletb.2008.04.059 | IPPP/07/34, DCPT/07/68 | hep-ph astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | If the dark matter of the Universe is constituted by weakly interacting
massive particles (WIMP), they would accumulate in the core of astrophysical
objects as the Sun and annihilate into particles of the Standard Model.
High-energy neutrinos would be produced in the annihilations, both directly and
via the subsequent decay of leptons, quarks and bosons. While Cherenkov
neutrino detectors/telescopes can only count the number of neutrinos above some
threshold energy, we study how, by exploiting their energy resolution, large
magnetized iron calorimeter and, possibly, liquid argon and totally active
scintillator detectors, planned for future long baseline neutrino experiments,
have the capability of reconstructing the neutrino spectrum and might provide
information on the dark matter properties. In particular, for a given value of
the WIMP mass, we show that a future iron calorimeter could break the
degeneracy between the WIMP-proton cross section and the annihilation branching
ratios, present for Cherenkov detectors, and constrain their values with good
accuracy.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 18:48:18 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jun 2008 17:18:45 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mena",
"Olga",
"",
"INFN, Rome; Rome U."
],
[
"Palomares-Ruiz",
"Sergio",
"",
"Durham U., IPPP"
],
[
"Pascoli",
"Silvia",
"",
"Durham U., IPPP"
]
] |
0706.3910 | Carlos Navia C. navia | C. E. Navia, C. R. A. Augusto, M. B. Robba and K. H. Tsui | Evidences of high energy protons with energies beyond 0.4 GeV in the
solar particle spectrum as responsible for the cosmic rays solar diurnal
anisotropy | 16 pages,15 figures | null | null | null | astro-ph | null | Analysis on the daily variations of cosmic ray muons with $E_{\mu}\geq 0.2
GeV$ based on the data of two directional muon telescopes at sea level and with
a rigidity of response to cosmic proton spectrum above 0.4 GV is presented. The
analysis covers two months of observations and in 60% of days, abrupt
transitions between a low to a high muon intensity and vice-verse is observed,
the period of high muon intensity is from $\sim 8.0h$ up to $\sim 19.0h$ (local
time) and coincides with the period when the interplanetary magnetic field
(IMF) lines overtake the Earth. This behavior strongly suggest that the high
muon intensity is due to a contribution of solar protons (ions) on the muon
intensity produced by the galactic cosmic rays, responsible for the low muon
intensity. This implies that the solar particle spectrum extends to energies
beyond 1 GeV. We show that this picture can explain the solar daily variation
origin, and it is a most accurate scenario than the assumption of corotating
galactic cosmic ray with the IMF lines, specially in the high rigidity region.
Obtained results are consistent with the data reported in others papers. Some
aspects on the sensitivity of our muon telescopes are also presented.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 20:49:01 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Navia",
"C. E.",
""
],
[
"Augusto",
"C. R. A.",
""
],
[
"Robba",
"M. B.",
""
],
[
"Tsui",
"K. H.",
""
]
] |
0706.3911 | John G. Ratcliffe | Michael L. Mihalik and John G. Ratcliffe | On the rank of a Coxeter group | 21 pages | null | null | null | math.GR | null | Let W be a Coxeter group with Coxeter generators S. The rank of the Coxeter
system (W,S) is the cardinality |S| of S. The Coxeter system (W,S) has finite
rank if and only if W is finitely generated. If (W,S) has infinite rank, then
|S| = |W|, since every element of W is represented by a finite product of
elements of S. Thus if W is not finitely generated, the rank of (W,S) is
uniquely determined by W. If W is finitely generated, then W may have sets of
Coxeter generators S and S' of different ranks. In this paper, we determine the
set of all possible ranks for an arbitrary finitely generated Coxeter group W.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 21:01:15 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Mihalik",
"Michael L.",
""
],
[
"Ratcliffe",
"John G.",
""
]
] |
0706.3912 | Ivan Penkov | Ivan Penkov, Alexander S. Tikhomirov | Triviality of vector bundles on sufficiently twisted ind-Grassmannians | null | null | null | null | math.AG | null | Twisted ind-Grassmannians are ind-varieties $\GG$ obtained as direct limits
of Grassmannians $G(r_m,V^{r_m})$, for $m\in\ZZ_{>0}$, under embeddings
$\phi_m:G(r_m,V^{r_m})\to G(r_{m+1}, V^{r_{m+1}})$ of degree greater than one.
It has been conjectured in \cite{PT} and \cite{DP} that any vector bundle of
finite rank on a twisted ind-Grassmannian is trivial. We prove this conjecture
under the assumption that the ind-Grassmannian $\GG$ is sufficiently twisted,
i.e. that $\lim_{m\to\infty}\frac{r_m}{\deg \phi_1...\deg\phi_m}=0$.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 18:31:50 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Penkov",
"Ivan",
""
],
[
"Tikhomirov",
"Alexander S.",
""
]
] |
0706.3913 | Dimitar Stoyanov | Dimitar G. Stoyanov | Current-voltage characteristic of parallel-plane ionization chamber with
inhomogeneous ionization | 8 pages, 4 figures | JINST2:P08007,2007 | 10.1088/1748-0221/2/08/P08007 | null | physics.gen-ph physics.plasm-ph | null | The balances of particles and charges in the volume of parallel-plane
ionization chamber are considered. Differential equations describing the
distribution of current densities in the chamber volume are obtained. As a
result of the differential equations solution an analytical form of the
current-voltage characteristic of parallel-plane ionization chamber with
inhomogeneous ionization in the volume is got.
| [
{
"version": "v1",
"created": "Wed, 27 Jun 2007 18:24:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Stoyanov",
"Dimitar G.",
""
]
] |
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