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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0708.2649 | Pulak Ranjan Giri | Pulak Ranjan Giri | Quantization of neutron in Earth's gravity | 2 pages, revtex, references added | null | null | SINP/TNP/2007/24 | hep-th quant-ph | null | Gravity is the weakest of all four known forces in the universe. Quantum
states of an elementary particle due to such a weak field is certainly very
shallow and would therefore be an experimental challenge to detect. Recently an
experimental attempt was made by V. V. Nesvizhevsky et al., Nature 415, 297
(2002), to measure the quantum states of a neutron, which shows that ground
state and few excited states are \sim 10^{-12}eV. We show that the energy of
the ground state of a neutron confined above Earth's surface should be \sim
10^{-37}eV. The experimentally observed energy levels are 10^{25} times deeper
than the actual energy levels it should be and thus certainly not due to
gravitational effect of Earth. Therefore the correct interpretation for the
painstaking experimental results of Ref. \cite{nes1} is due to the confinement
potential of a one dimensional box of length L \sim 50\mu m, generated from the
experimental setup as commented before \cite{hansoon}. Our results thus creates
a new challenge to the experimentalist to resolve the shallow energy levels of
the neutron in Earth's gravitational field in future.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 12:57:17 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 14:18:45 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Giri",
"Pulak Ranjan",
""
]
] |
0708.2650 | Marcos Montenegro | Jurandir Ceccon, Marcos Montenegro | Optimal L^p-Riemannian Gagliardo-Nirenberg inequalities | 23 pages. To appear in Mathematische Zeitschrift | null | null | null | math.DG math.AP | null | Let (M,g) be a compact Riemannian manifold of dimension n \geq 2. In this
work we prove the validity of the optimal L^p-Riemannian Gagliardo-Nirenberg
inequality for 1 < p \leq 2. Our proof relies strongly on a new distance lemma
which. In particular, we extend L^p-Euclidean Gagliardo-Nirenberg inequalities
due to Del Pino and Dolbeault and the optimal L^2-Riemannian
Gagliardo-Nirenberg inequality due to Broutteland in a unified framework.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:16:12 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 13:33:00 GMT"
},
{
"version": "v3",
"created": "Wed, 22 Aug 2007 01:28:50 GMT"
},
{
"version": "v4",
"created": "Thu, 23 Aug 2007 23:25:26 GMT"
}
] | 2007-08-24T00:00:00 | [
[
"Ceccon",
"Jurandir",
""
],
[
"Montenegro",
"Marcos",
""
]
] |
0708.2651 | Alexander Lytchak | Alexander Lytchak | Notes on the Jacobi equation | 10 Pages, typos corrected, references added | null | null | null | math.DG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss some properties of Jacobi fields that do not involve assumptions
on the curvature endomorphism. We compare indices of different spaces of Jacobi
fields and give some applications to Riemannian geometry.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:07:38 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Jul 2008 10:52:54 GMT"
}
] | 2008-07-02T00:00:00 | [
[
"Lytchak",
"Alexander",
""
]
] |
0708.2652 | Takeo Kato | T. Kato, A. A. Golubov, Y. Nakamura | Decoherence in a superconducting flux qubit with a pi-junction | 5 pages, 2 figures | null | 10.1103/PhysRevB.76.172502 | null | cond-mat.mes-hall cond-mat.supr-con | null | We consider the use of a pi-junction for flux qubits to realize degenerate
quantum levels without external magnetic field. On the basis of the
Caldeira-Leggett model, we derive an effective spin-Boson model, and study
decoherece of this type of qubits. We estimate the dephasing time by using
parameters from recent experiments of SIFS junctions, and show that high
critical current and large subgap resistance are required for the pi-junction
to realize a long coherent time.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:10:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kato",
"T.",
""
],
[
"Golubov",
"A. A.",
""
],
[
"Nakamura",
"Y.",
""
]
] |
0708.2653 | Yury Bliokh P | Konstantin Y. Bliokh, Yuri P. Bliokh, Valentin Freilikher, Sergey
Savel'ev, and Franco Nori | Unusual Resonators: Plasmonics, Metamaterials, and Random Media | 13 pages, 9 figures | Rev. Mod. Phys. 80, 1201 (2008) | 10.1103/RevModPhys.80.1201 | null | physics.optics cond-mat.other physics.plasm-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Superresolution, extraordinary transmission, total absorption, and
localization of electromagnetic waves are currently attracting growing
attention. These phenomena are related to different physical objects and are
usually studied within the context of different, sometimes rather
sophisticated, physical approaches. Remarkably, all these seemingly unrelated
phenomena owe their origin to the same underlying physical mechanism - wave
interaction with an open resonator. Here we show that it is possible to
describe all of these effects in a unified way, mapping each system onto a
simple resonator model. Such description provides a thorough understanding of
the phenomena, explains all the main features of their complex behaviour, and
enables to control the system via the resonator parameters: eigenfrequencies,
Q-factors, and coupling coefficients.
| [
{
"version": "v1",
"created": "Sun, 19 Aug 2007 12:50:02 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 16:56:00 GMT"
},
{
"version": "v3",
"created": "Mon, 13 Oct 2008 08:36:54 GMT"
}
] | 2008-10-13T00:00:00 | [
[
"Bliokh",
"Konstantin Y.",
""
],
[
"Bliokh",
"Yuri P.",
""
],
[
"Freilikher",
"Valentin",
""
],
[
"Savel'ev",
"Sergey",
""
],
[
"Nori",
"Franco",
""
]
] |
0708.2654 | Claude Berthier | K. Hiraki (LSP, Gakushuin University, Tokyo), H. Mayaffre (LSP), M.
Horvatic (LCMI), C. Berthier (LSP, Lcmi), S. Uji (NRIM), T. Yamaguchi (NRIM),
H. Tanaka (AIST), A. Kobayashi (NIHON University), H. Kobayashi (Institute
for Molecular Sciences), T. Takahashi (Gakushuin University, Tokyo) | $^{77}$Se NMR evidence for the Jaccarino-Peter mechanism in the field
induced superconductor, $\lambda$(BETS)$_2$FeCl$_4$} | null | Journal of the Physical Society of Japan 76, 12 (2007) 124708-1 | 10.1143/JPSJ.76.124708 | null | cond-mat.str-el cond-mat.supr-con | null | We have performed $^{77}$Se NMR on a single crystal sample of the field
induced superconductor $\lambda$-(BETS)$_{2}$FeCl$_{4}$. Our results obtained
in the paramagnetic state provide a microscopic insight on the exchange
interaction $J$ between the spins \textbf{s} of the BETS $\pi$ conduction
electrons and the Fe localized $d$ spins \textbf{S}. The absolute value of the
Knight shift \textbf{K} decreases when the polarization of the Fe spins
increases. This reflects the ``negative'' spin polarization of the $\pi$
electrons through the exchange interaction $J$. The value of $J$ has been
estimated from the temperature and the magnetic field dependence of \textbf{K}
and found in good agreement with that deduced from transport measurements (L.
Balicas \textit{et al}. Phys. Rev. Lett. \textbf{87}, 067002 (2001)). This
provides a direct microscopic evidence that the field induced superconductivity
is due to the compensation effect predicted by Jaccarino and Peter (Phys. Rev.
Lett. \textbf{9}, 290 (1962)). Furthermore, an anomalous broadening of the NMR
line has been observed at low temperature, which suggests the existence of
charge disproportionation in the metallic state neighboring the superconducting
phase.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:28:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hiraki",
"K.",
"",
"LSP, Gakushuin University, Tokyo"
],
[
"Mayaffre",
"H.",
"",
"LSP"
],
[
"Horvatic",
"M.",
"",
"LCMI"
],
[
"Berthier",
"C.",
"",
"LSP, Lcmi"
],
[
"Uji",
"S.",
"",
"NRIM"
],
[
"Yamaguchi",
"T.",
"",
"NRIM"
],
[
"Tanaka",
"H.",
"",
"AIST"
],
[
"Kobayashi",
"A.",
"",
"NIHON University"
],
[
"Kobayashi",
"H.",
"",
"Institute\n for Molecular Sciences"
],
[
"Takahashi",
"T.",
"",
"Gakushuin University, Tokyo"
]
] |
0708.2655 | Andrew Buckley | Andy Buckley | CEDAR: tools for event generator tuning | 13 pages, prepared for XI International Workshop on Advanced
Computing and Analysis Techniques in Physics Research, Amsterdam, April 23-27
2007 | PoSACAT2007:050,2007 | null | null | hep-ph | null | I describe the work of the CEDAR collaboration in developing tools for tuning
and validating Monte Carlo event generator programs. The core CEDAR task is to
interface the Durham HepData database of experimental measurements to event
generator validation tools such as the UCL JetWeb system - this has
necessitated the migration of HepData to a new relational database system and a
Java-based interaction model. The "number crunching" part of JetWeb is also
being upgraded, from the Fortran HZTool library to the new C++ Rivet system and
a generator interfacing layer named RivetGun. Finally, I describe how Rivet is
already being used as a central part of a new generator tuning system, and
summarise two other CEDAR activities, HepML and HepForge.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:29:15 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Aug 2007 15:39:16 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Buckley",
"Andy",
""
]
] |
0708.2656 | Elizabeth Winstanley | Elizabeth Winstanley | Hawking radiation from rotating brane black holes | 19 pages, 13 figures, talk given at the ``Workshop on Dynamics and
Thermodynamics of Black Holes and Naked Singularities II'', Milan, 10-12 May
2007 | null | null | null | hep-th gr-qc hep-ph | null | We review recent work on the Hawking radiation of rotating brane black holes,
as may be produced at the LHC. We outline the methodology for calculating the
fluxes of particles, energy and angular momentum by spin-0, spin-1/2 and spin-1
quantum fields on the brane. We briefly review some of the key features of the
emission, in particular the changes in the spectra as the number of extra
dimensions or the angular velocity of the black hole increases. These
quantities will be useful for accurate simulations of black hole events at the
LHC.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:56:22 GMT"
},
{
"version": "v2",
"created": "Tue, 28 Aug 2007 15:50:11 GMT"
}
] | 2007-08-28T00:00:00 | [
[
"Winstanley",
"Elizabeth",
""
]
] |
0708.2657 | Daniel Burgarth | Daniel Burgarth, Vittorio Giovannetti | Mediated Homogenization | 6 pages, 6 figures | Phys. Rev. A 76, 062307 (2007) | 10.1103/PhysRevA.76.062307 | null | quant-ph | null | Homogenization protocols model the quantum mechanical evolution of a system
to a fixed state independently from its initial configuration by repeatedly
coupling it with a collection of identical ancillas. Here we analyze these
protocols within the formalism of "relaxing" channels providing an easy to
check sufficient condition for homogenization. In this context we describe
mediated homogenization schemes where a network of connected qudits relaxes to
a fixed state by only partially interacting with a bath. We also study
configurations which allow us to introduce entanglement among the elements of
the network. Finally we analyze the effect of having competitive configurations
with two different baths and we prove the convergence to dynamical equilibrium
for Heisenberg chains.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:40:39 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 15:11:21 GMT"
}
] | 2007-12-13T00:00:00 | [
[
"Burgarth",
"Daniel",
""
],
[
"Giovannetti",
"Vittorio",
""
]
] |
0708.2658 | Marek Zawadowski | Marek Zawadowski | On positive opetopes, positive opetopic cardinals and positive opetopic
set | 88 pages | null | null | null | math.GT | http://creativecommons.org/licenses/by/4.0/ | We introduce the notion of a positive opetope and positive opetopic cardinals
as certain finite combinatorial structures. The positive opetopic cardinals to
positive-to-one polygraphs are like simple graphs to free omega-categories over
omega-graphs, c.f. [MZ]. In particular, they allow us to give an explicit
combinatorial description of positive-to-one polygraphs. Using this description
we show, among other things, that positive-to-one polygraphs form a presheaf
category with the exponent category being the category of positive opetopes. We
also show that the category of omega-categories is monadic over the category of
positive-to-one polygraphs with the `free functor' being an inclusion.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:44:13 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Apr 2023 07:18:21 GMT"
}
] | 2023-04-12T00:00:00 | [
[
"Zawadowski",
"Marek",
""
]
] |
0708.2659 | Marek Zawadowski | Marek Zawadowski | On ordered face structures and many-to-one computads | 97 pages; some minor errors corrected | null | null | null | math.CT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce the notion of an ordered face structure. The ordered face
structures to many-to-one computads are like positive face structures to
positive-to-one computads. This allow us to give an explicit combinatorial
description of many-to-one computads in terms of ordered face structures.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:48:23 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jun 2008 22:22:10 GMT"
}
] | 2008-06-17T00:00:00 | [
[
"Zawadowski",
"Marek",
""
]
] |
0708.2660 | Grzegorz Wilk | G.Wilk and Z.Wlodarczyk | Tsallis distribution from minimally selected order statistics | Presented by G.Wilk at the Int. Conf. on Complexity, Metastability
and Nonextensivity, Dept. of Physics and Astronomy, Univ. of Catania,
Catania, 1-5 July 2007, Italy. To appear in the proceedings | AIP Conference Proceedings 965 (2007) 76-79 | 10.1063/1.2828762 | null | cond-mat.stat-mech hep-ph | null | We demonstrate that selection of the minimal value of ordered variables leads
in a natural way to its distribution being given by the Tsallis distribution,
the same as that resulting from Tsallis nonextensive statistics. The possible
application of this result to the multiparticle production processes is
indicated.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:53:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wilk",
"G.",
""
],
[
"Wlodarczyk",
"Z.",
""
]
] |
0708.2661 | Vernesa Smolcic | V. Smolcic, D. Zucker, E. F. Bell, M. G. Coleman, H. W. Rix, E.
Schinnerer, Z. Ivezic, A. Kniazev | Improved photometry of SDSS crowded field images: Structure and dark
matter content in the dwarf spheroidal galaxy Leo I | 13 pages, 11 figures; accepted for publication in AJ | Astron.J.134:1901-1915,2007 | 10.1086/522369 | null | astro-ph | null | We explore how well crowded field point-source photometry can be accomplished
with SDSS data: We present a photometric pipeline based on DoPhot, and tuned
for analyzing crowded-field images from the SDSS. Using Monte Carlo simulations
we show that the completeness of source extraction is above 80% to i < 21 (AB)
and a stellar surface density of about 200 sq.amin. Hence, a specialized data
pipeline can efficiently be used for e.g. nearby resolved galaxies in SDSS
images, where the standard SDSS photometric package Photo, when applied in
normal survey mode, gives poor results. We apply our pipeline to an area of
about 3.55sq.deg. around the dwarf spheroidal galaxy (dSph) Leo I, and
construct a high S/N star-count map of Leo I via an optimized filter in
color-magnitude space (g,r,i). Although the radial surface-density profile of
the dwarf deviates from the best fit empirical King model towards outer radii,
we find no evidence for tidal debris out to a stellar surface-density of
4*10^(-3) of the central value. We determine the total luminosity of Leo I, and
model its mass using the spherical and isotropic Jeans equation. Assuming that
'mass follows light' we constrain a lower limit of the total mass of the dSph
to be (1.7+/-0.2)*10^7 Msol. Contrary, if the mass in Leo I is dominated by a
constant density dark-matter (DM) halo, then the mass within the central 12' is
(2+/-0.6)*10^8 Msol. This leads to a mass-to-light ratio of >>6 (Ic_sol), and
possibly >75 if the DM halo dominates the mass and extends further out than
12'. In summary, our results show that Leo I is a symmetric, relaxed and bound
system; this supports the idea that Leo I is a dark-matter dominated system.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:21:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Smolcic",
"V.",
""
],
[
"Zucker",
"D.",
""
],
[
"Bell",
"E. F.",
""
],
[
"Coleman",
"M. G.",
""
],
[
"Rix",
"H. W.",
""
],
[
"Schinnerer",
"E.",
""
],
[
"Ivezic",
"Z.",
""
],
[
"Kniazev",
"A.",
""
]
] |
0708.2662 | Martin Kirkengen | Martin Kirkengen, Joakim Bergli, Yuri M. Galperin | Direct generation of charge carriers in c-Si solar cells due to embedded
nanoparticles | 1 figure | null | 10.1063/1.2809368 | null | cond-mat.other | null | It is known that silicon is an indirect band gap material, reducing its
efficiency in photovoltaic applications. Using surface plasmons in metallic
nanoparticles embedded in a solar cell has recently been proposed as a way to
increase the efficiency of thin film silicon solar cells. The dipole mode that
dominates the plasmons in small particles produces an electric field having
Fourier components with all wave numbers. In this work, we show that such a
field creates electron-hole-pairs without phonon assistance, and discuss the
importance of this effect compared to radiation from the particle and losses
due to heating.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 13:55:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kirkengen",
"Martin",
""
],
[
"Bergli",
"Joakim",
""
],
[
"Galperin",
"Yuri M.",
""
]
] |
0708.2663 | Joshua E. S. Socolar | Joshua E. S. Socolar | Hexagonal parquet tilings: k-isohedral monotiles with arbitrarily large
k | 7 pages, 8 figures. Published in The Mathematical Intelligencer.
NOTE: The MI mistakenly published an earlier draft | Mathematical Intelligencer, Volume 29, Number 2, pages 33-38
(2007) | null | null | cond-mat.other math.GM math.MG | null | This paper addresses the question of whether a single tile with nearest
neighbor matching rules can force a tiling in which the tiles fall into a large
number of isohedral classes. A single tile is exhibited that can fill the
Euclidean plane only with a tiling that contains k distinct isohedral sets of
tiles, where k can be made arbitrarily large. It is shown that the construction
cannot work for a simply connected 2D tile with matching rules for adjacent
tiles enforced by shape alone. It is also shown that any of the following
modifications allows the construction to work: (1) coloring the edges of the
tiling and imposing rules on which colors can touch; (2) allowing the tile to
be multiply connected; (3) requiring maximum density rather than space-filling;
(4) allowing the tile to have a thickness in the third dimension.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:08:43 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Socolar",
"Joshua E. S.",
""
]
] |
0708.2664 | Charles Young | N. Crampe, C. A. S. Young | Sutherland Models for Complex Reflection Groups | 26 pages, 8 figures, latex; v3, acknowledgement added | Nucl.Phys.B797:499-519,2008 | 10.1016/j.nuclphysb.2007.11.028 | DCPT-07/41 | math-ph hep-th math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | There are known to be integrable Sutherland models associated to every real
root system -- or, which is almost equivalent, to every real reflection group.
Real reflection groups are special cases of complex reflection groups. In this
paper we associate certain integrable Sutherland models to the classical family
of complex reflection groups. Internal degrees of freedom are introduced,
defining dynamical spin chains, and the freezing limit taken to obtain static
chains of Haldane-Shastry type. By considering the relation of these models to
the usual BC_N case, we are led to systems with both real and complex
reflection groups as symmetries. We demonstrate their integrability by means of
new Dunkl operators, associated to wreath products of dihedral groups.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:04:59 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Nov 2007 15:32:15 GMT"
},
{
"version": "v3",
"created": "Tue, 18 May 2010 06:48:17 GMT"
}
] | 2010-05-25T00:00:00 | [
[
"Crampe",
"N.",
""
],
[
"Young",
"C. A. S.",
""
]
] |
0708.2665 | Hans Dijkstra | H. Dijkstra | The LHCb Upgrade | Flavor Physics & CP Violation Conference, Bled, 2007 | ECONFC070512:027,2007 | null | fpcp07-423 | hep-ex | null | The LHCb detector has been designed to study CP violation and other rare
phenomena in B-meson decays up to a luminosity of $\sim 5.10^{32}\rm
cm^{-2}s^{-1}$. This paper will describe what is limiting LHCb to exploit the
much higher luminosities available at the LHC, and what are the baseline
modifications which will remedy these limitations. The aim of SuperLHCb is to
increase the yields in hadronic B-decay channels by about a factor twenty
compared to LHCb, while for channels with leptons in the final state a factor
ten increase in statistics is envisaged.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:06:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dijkstra",
"H.",
""
]
] |
0708.2666 | Francois Fillastre | Fran\c{c}ois Fillastre, Ivan Izmestiev (IFM) | Hyperbolic cusps with convex polyhedral boundary | null | Geom. Topol. 13 (2009) 457-492 | 10.2140/gt.2009.13.457 | null | math.DG | null | We prove that a 3-dimensional hyperbolic cusp with convex polyhedral boundary
is uniquely determined by the metric induced on its boundary. Furthemore, any
hyperbolic metric on the torus with cone singularities of positive curvature
can be realized as the induced metric on the boundary of a convex polyhedral
cusp. The proof uses the total scalar curvature functional on the space of
``cusps with particles'', which are hyperbolic cone-manifolds with the singular
locus a union of half-lines. We prove, in addition, that convex polyhedral
cusps with particles are rigid with respect to the induced metric on the
boundary and the curvatures of the singular locus. Our main theorem is
equivalent to a part of a general statement about isometric immersions of
compact surfaces.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:07:45 GMT"
}
] | 2014-11-11T00:00:00 | [
[
"Fillastre",
"François",
"",
"IFM"
],
[
"Izmestiev",
"Ivan",
"",
"IFM"
]
] |
0708.2667 | Michael Hartmann Mr | Michael J. Hartmann and Martin B. Plenio | Migration of bosonic particles across a Mott insulator to superfluid
phase interface | 5 pages, 6 figures, to appear in Phys. Rev. Lett | Phys. Rev. Lett. 100, 070602 (2008) | 10.1103/PhysRevLett.100.070602 | null | cond-mat.str-el cond-mat.stat-mech quant-ph | null | We consider a boundary between a Mott insulator and a superfluid region of a
Bose-Hubbard model at unit filling. Initially both regions are decoupled and
cooled to their respective ground states. We show that, after switching on a
small tunneling rate between both regions, all particles of the Mott region
migrate to the superfluid area. This migration takes place whenever the
difference between the chemical potentials of both regions is less than the
maximal energy of any eigenmode of the superfluid. We verify our results
numerically with DMRG simulations and explain them analytically with a master
equation approximation, finding good agreement between both approaches. Finally
we carry out a feasibility study for the observation of the effect in coupled
arrays of micro-cavities and optical lattices.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:08:28 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jan 2008 15:07:46 GMT"
}
] | 2008-02-20T00:00:00 | [
[
"Hartmann",
"Michael J.",
""
],
[
"Plenio",
"Martin B.",
""
]
] |
0708.2668 | Daniel Reem | Daniel Reem, Simeon Reich | Zone and double zone diagrams in abstract spaces | 17 pages, 5 figures; slight modifications and additions (including
thanks); Theorem 5.5 was slightly improved. This version is essentially from
the beginning of 2009 and it does not take into account several developments
which have occurred since then | Colloquium Mathematicum 115 (2009), 129-145 | 10.4064/cm115-1-11 | null | math.MG cs.CG math.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A zone diagram is a relatively new concept which was first defined and
studied by T. Asano, J. Matousek and T. Tokuyama. It can be interpreted as a
state of equilibrium between several mutually hostile kingdoms. Formally, it is
a fixed point of a certain mapping. These authors considered the Euclidean
plane and proved the existence and uniqueness of zone diagrams there. In the
present paper we generalize this concept in various ways. We consider general
sites in m-spaces (a simple generalization of metric spaces) and prove several
existence and (non)uniqueness results in this setting. In contrast to previous
works, our (rather simple) proofs are based on purely order theoretic
arguments. Many explicit examples are given, and some of them illustrate new
phenomena which occur in the general case. We also re-interpret zone diagrams
as a stable configuration in a certain combinatorial game, and provide an
algorithm for finding this configuration in a particular case.
| [
{
"version": "v1",
"created": "Sun, 19 Aug 2007 15:35:25 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jul 2011 13:30:41 GMT"
}
] | 2017-03-06T00:00:00 | [
[
"Reem",
"Daniel",
""
],
[
"Reich",
"Simeon",
""
]
] |
0708.2669 | Liviu Nicolaescu | Liviu I. Nicolaescu | Schubert calculus on the grassmannian of hermitian lagrangian spaces | 52 pages, 1 figure. Fixed typos, added new references | null | null | null | math.GT math.AT math.DG | null | The grassmannian of hermitian lagrangian spaces in $\mathbb{C}^n\oplus
\mathbb{C}^n$ is a natural compactification of the space of hermitian $n\times
n$ matrices. We describe a Schubert-like, Whitney regular stratification on
this space which has a Morse theoretic origin. We prove that these strata
define closed subanalytic currents \`{a} la R. Hardt, generating the integral
homology of this space, we investigate their intersection theoretic properties,
and we prove certain odd (in K-theoretic sense) Thom-Porteous type theorems.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:11:22 GMT"
},
{
"version": "v2",
"created": "Mon, 27 Aug 2007 18:24:21 GMT"
},
{
"version": "v3",
"created": "Thu, 20 Sep 2007 20:32:38 GMT"
}
] | 2007-09-20T00:00:00 | [
[
"Nicolaescu",
"Liviu I.",
""
]
] |
0708.2670 | Christian Hoerhammer | C. Hoerhammer and H. Buettner | Environment-induced two-mode entanglement in quantum Brownian motion | 8 pages, 6 figures | null | 10.1103/PhysRevA.77.042305 | null | quant-ph | null | The time evolution of quantum correlations of entangled two-mode continuous
variable states is examined in single-reservoir as well as two-reservoir
models, representing noisy correlated or uncorrelated non-Markovian quantum
channels. For this purpose the model of quantum Brownian motion is extended.
Various separability criteria for Gaussian continuous variable systems are
applied. In both types of reservoir models moderate non-Markovian effects
prolong the separability time scales. However, in these models the properties
of the stationary state may differ. In the two-reservoir model the initial
entanglement is completely lost and both modes are finally uncorrelated. In a
common reservoir both modes interact indirectly via the coupling to the same
bath variables. Below a critical bath temperature entanglement between the two
modes is preserved even in the steady state. A separability criterion is
derived, which depends on the bath temperature and the response function of the
open quantum system. Thus, the extended quantum Brownian motion model of a
two-mode continuous variable system in a common reservoir provides an example
of environment-induced entanglement.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:46:40 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 16:49:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hoerhammer",
"C.",
""
],
[
"Buettner",
"H.",
""
]
] |
0708.2671 | Michael Kapovich | Michael Kapovich | On sequences of finitely generated discrete groups | 21 pages, 1 figure | null | null | null | math.GR math.GT | null | We consider sequences of finitely generated discrete subgroups
Gamma_i=rho_i(Gamma) of a rank 1 Lie group G, where the representations rho_i
are not necessarily faithful. We show that, for algebraically convergent
sequences (Gamma_i), unless Gamma_i's are (eventually) elementary or contain
normal finite subgroups of arbitrarily high order, their algebraic limit is a
discrete nonelementary subgroup of G. In the case of divergent sequences
(Gamma_i) we show that the limiting action on a real tree T satisfies certain
semistability condition, which generalizes the notion of stability introduced
by Rips. We then verify that the group Gamma splits as an amalgam or HNN
extension of finitely generated groups, so that the edge group has an amenable
image in the isometry group of T.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:34:06 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Kapovich",
"Michael",
""
]
] |
0708.2672 | Nathan de Vries | N. de Vries, I.A.G. Snellen, R.T. Schilizzi, M.D. Lehnert and M.N.
Bremer | Massive galaxies with very young AGN | To appear in the proceedings of "Formation and Evolution of Galaxy
Bulges", IAUS 245; M. Bureau, E. Athanassoula & B. Barbuy, eds | null | 10.1017/S1743921308017870 | null | astro-ph | null | Gigahertz Peaked Spectrum (GPS) radio galaxies are generally thought to be
the young counterparts of classical extended radio sources and live in massive
ellipticals. GPS sources are vital for studying the early evolution of
radio-loud AGN, the trigger of their nuclear activity, and the importance of
feedback in galaxy evolution. We study the Parkes half-Jansky sample of GPS
radio galaxies of which now all host galaxies have been identified and 80% has
their redshifts determined (0.122 < z < 1.539). Analysis of the absolute
magnitudes of the GPS host galaxies show that at z > 1 they are on average a
magnitude fainter than classical 3C radio galaxies. This suggests that the AGN
in young radio galaxies have not yet much influenced the overall properties of
the host galaxy. However their restframe UV luminosities indicate that there is
a low level of excess as compared to passive evolution models.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:34:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"de Vries",
"N.",
""
],
[
"Snellen",
"I. A. G.",
""
],
[
"Schilizzi",
"R. T.",
""
],
[
"Lehnert",
"M. D.",
""
],
[
"Bremer",
"M. N.",
""
]
] |
0708.2673 | Yosef Verbin | Y. Verbin | Solitonic and Non-Solitonic Q-Stars | To appear in the proceedings of 11th Marcel Grossmann Meeting,
Berlin, July 2006 | null | 10.1142/9789812834300_0396 | null | gr-qc hep-th | null | The properties of several types of Q-stars are studied and compared with
their flat space analogues, i.e. Q-balls. The analysis is based on calculating
the mass, global U(1) charge and binding energy for families of solutions
parametrized by the central value of the scalar field. The two most frequently
used Q-star models (differing by their potential term) are studied. Although
there are general similarities between both Q-star types, there are important
differences as well as new features with respect to the non-gravitating
systems. We find non-solitonic solutions which do not have a flat space limit,
in the weak (scalar) field region as well as in the opposite region of strong
central scalar field for which there does not exist Q-ball solutions at all.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:36:28 GMT"
}
] | 2016-11-15T00:00:00 | [
[
"Verbin",
"Y.",
""
]
] |
0708.2674 | Jussi Lindgren I | Jussi Ilmari Lindgren | Governing Dynamics from cause and effect: -A novel formulation for
causality with applications in Quantum Gravity and Economic Theory | null | null | null | null | physics.gen-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper defines an equation for causality. This equation is then combined
with the postulates of quantum mechanics and mass-energy equivalence to produce
a quantum mechanical telegrapher's equation and to reproduce the Schrodinger
and Klein-Gordon equations. The incompressible Navier-Stokes equations and
dynamic general equilibrium in economics (with an interpretation of a Nash
equilibrium) are obtained when the equation of causality refers to itself, i.e.
when the cause is its own effect. As it is shown that the Klein-Gordon equation
is obtained by Wick rotating the cause vector with de Broglie angular
frequency, this paper postulates an equation for Quantum Gravity, which relates
the Navier-Stokes equations to the Einstein Field Equations of General
Relativity.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:36:59 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Jun 2010 16:17:58 GMT"
},
{
"version": "v3",
"created": "Wed, 9 Jun 2010 18:11:36 GMT"
},
{
"version": "v4",
"created": "Tue, 14 Sep 2010 17:21:52 GMT"
},
{
"version": "v5",
"created": "Thu, 30 Sep 2010 18:57:52 GMT"
},
{
"version": "v6",
"created": "Wed, 13 Feb 2013 20:23:33 GMT"
}
] | 2014-02-11T00:00:00 | [
[
"Lindgren",
"Jussi Ilmari",
""
]
] |
0708.2675 | Igor Strakovsky | Ya. Azimov (PNPI), K. Goeke (Ruhr-Universitet), I. Strakovsky (GWU) | An explanation why the Theta+ is seen in some experiments and not in
others | The shortened and slightly modified version of arXiv:0704.3045,
accepted for publication in Phys. Rev. D | Phys.Rev.D76:074013,2007 | 10.1103/PhysRevD.76.074013 | null | hep-ph hep-ex nucl-ex nucl-th | null | To understand the whole set of positive and null data on the Theta+(1530) -
production, we suggest the hypothesis that multiquark hadrons are mainly
generated from many-quark states, which emerge either as short-term hadron
fluctuations, or as hadron remnants in hard processes. This approach allows us
to describe both non-observation of the Theta+ in current null experiments and
peculiar features of its production in positive experiments. Further, we are
able to propose new experiments that might be decisive for the problem of the
Theta+ existence. Studies of properties and distributions of the Theta+ in such
experiments can give important information on the structure of both
conventional and multiquark hadrons. It would provide better insight into how
QCD works.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:42:16 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Azimov",
"Ya.",
"",
"PNPI"
],
[
"Goeke",
"K.",
"",
"Ruhr-Universitet"
],
[
"Strakovsky",
"I.",
"",
"GWU"
]
] |
0708.2676 | Yuri Lyubchik | Yu. Lyubchik (MAO Nasu), H. R. A. Jones (CAR Uh), Ya. V. Pavlenko (MAO
Nasu), E. Martin (IAC, Ucf), I. S. McLean (UCLA), L. Prato (Lowell Obs.), R.
J. Barber (UCL), J. Tennyson (UCL) | Spectral analysis of high resolution near-infrared spectra of ultra cool
dwarfs | 11 pages, 9 figures, 4 tables; accepted for publication in the
Astron. and Astrophys | null | 10.1051/0004-6361:20065386 | null | astro-ph | null | We present an analysis of high resolution spectra in the J band of five ultra
cool dwarfs from M6 to L0. A new ab initio water vapour line list and existing
line lists of FeH and CrH were used for spectra modelling. We find a good fit
for the Mn I 12899.76 A line. This feature is one of the few for which we have
a reliable oscillator strength. Other atomic features are present but most of
the observed features are FeH and water lines. While we are uncertain about the
quality of many of the atomic line parameters, the FeH and CrH line lists
predict a number of features which are not apparent in our observed spectra. We
infer that the main limiting factor in our spectral analysis is the FeH and CrH
molecular spectra.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:42:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lyubchik",
"Yu.",
"",
"MAO Nasu"
],
[
"Jones",
"H. R. A.",
"",
"CAR Uh"
],
[
"Pavlenko",
"Ya. V.",
"",
"MAO\n Nasu"
],
[
"Martin",
"E.",
"",
"IAC, Ucf"
],
[
"McLean",
"I. S.",
"",
"UCLA"
],
[
"Prato",
"L.",
"",
"Lowell Obs."
],
[
"Barber",
"R. J.",
"",
"UCL"
],
[
"Tennyson",
"J.",
"",
"UCL"
]
] |
0708.2677 | Andres Santos | Rene D. Rohrmann and Andres Santos | Structure of hard-hypersphere fluids in odd dimensions | 18 pages, 7 figures; v2: new references added plus minor changes; to
be published in PRE | Phys. Rev. E 76, 051202 (2007) | 10.1103/PhysRevE.76.051202 | null | cond-mat.stat-mech cond-mat.soft physics.chem-ph | null | The structural properties of single component fluids of hard hyperspheres in
odd space dimensionalities $d$ are studied with an analytical approximation
method that generalizes the Rational Function Approximation earlier introduced
in the study of hard-sphere fluids [S. B. Yuste and A. Santos, Phys. Rev. A
{\bf 43}, 5418 (1991)]. The theory makes use of the exact form of the radial
distribution function to first order in density and extends it to finite
density by assuming a rational form for a function defined in Laplace space,
the coefficients being determined by simple physical requirements. Fourier
transform in terms of reverse Bessel polynomials constitute the mathematical
framework of this approximation, from which an analytical expression for the
static structure factor is obtained. In its most elementary form, the method
recovers the solution of the Percus-Yevick closure to the Ornstein-Zernike
equation for hyperspheres at odd dimension. The present formalism allows one to
go beyond by yielding solutions with thermodynamic consistency between the
virial and compressibility routes to any desired equation of state. Excellent
agreement with available computer simulation data at $d=5$ and $d=7$ is
obtained. As a byproduct of this study, an exact and explicit polynomial
expression for the intersection volume of two identical hyperspheres in
arbitrary odd dimensions is given.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:46:08 GMT"
},
{
"version": "v2",
"created": "Tue, 23 Oct 2007 08:51:59 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Rohrmann",
"Rene D.",
""
],
[
"Santos",
"Andres",
""
]
] |
0708.2678 | Michael Sigalov | M. Sigalov, E.O. Kamenetskii, and R. Shavit | Eigen electric moments of magnetic-dipolar modes in quasi-2D ferrite
disk particles | null | null | 10.1007/s00340-008-3168-2 | null | cond-mat.mtrl-sci cond-mat.mes-hall | null | A property associated with a vortex structure becomes evident from an
analysis of confinement phenomena of magnetic oscillations in a quasi-2D
ferrite disk with a dominating role of magnetic-dipolar
(non-exchange-interaction) spectra. The vortices are guaranteed by the chiral
edge states of magnetic-dipolar modes which result in appearance of eigen
electric moments oriented normally to the disk plane. Due to the
eigen-electric-moment properties, a ferrite disk placed in a microwave cavity
is strongly affected by the cavity RF electric field with a clear evidence for
multi-resonance oscillations. For different cavity parameters, one may observe
the "resonance absorption" and "resonance repulsion" behaviors.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 14:59:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sigalov",
"M.",
""
],
[
"Kamenetskii",
"E. O.",
""
],
[
"Shavit",
"R.",
""
]
] |
0708.2679 | Yitzhak Shnidman | Ismael Yacoubou-Djima and Yitzhak Shnidman (College of Staten Island,
City University of New York) | Flow-deformed conformations of entangled polymers as persistent random
walks | 76 pages, 11 figures | null | null | null | cond-mat.soft cond-mat.mtrl-sci cond-mat.stat-mech | null | Evolving structure and rheology across Kuhn scale interfaces in entangled
polymer fluids under flow play a prominent role in processing of manufactured
plastics, and have numerous other applications. Quantitative tracking of chain
conformation statistics on the Kuhn scale is essential for developing
computational models of such phenomena. For this purpose, we formulate here a
two-scale/two-mode model of entangled polymer chains under flow. Each chain is
partitioned by successive entanglements into strands that are in one of two
modes: entangled or dangling. On the strand scale, conformation statistics of
ideal (non-interacting) strands follows a differential evolution equation for
the second moment of its end-to-end distance. The latter regulates persistent
random walks sampling conformation statistics of ideal entangled strands on the
Kuhn scale, as follows from a generalized Green-Kubo relation and the Maximum
Entropy Principle. We test it numerically for a range of deformation rates at
the start-up of simple elongational and shear flows. A self-consistent
potential, representing segmental interactions, modifies strand conformation
statistics on the Kuhn scale, as it renormalizes the parameters controlling the
persistent random walk. The generalized Green-Kubo relation is then inverted to
determine how the second moment of the strand end-to-end distance is changed by
the self-consistent potential. This allows us to devise a two-scale propagation
scheme for the statistical weights of subchains of the entangled chain. The
latter is used to calculate local volume fractions for each chemical type of
Kuhn segments in entangled chains, thus determining the self-consistent
potential.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:06:31 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Yacoubou-Djima",
"Ismael",
"",
"College of Staten Island,\n City University of New York"
],
[
"Shnidman",
"Yitzhak",
"",
"College of Staten Island,\n City University of New York"
]
] |
0708.2680 | Gunnar M\"oller | Gunnar Moller, Steven H. Simon | Paired composite fermion wavefunctions | 4 pages, 2 figures | Phys. Rev. B 77, 075319 (2008) | 10.1103/PhysRevB.77.075319 | null | cond-mat.mes-hall | null | We construct a family of BCS paired composite fermion wavefunctions that
generalize, but remain in the same topological phase as, the Moore-Read
Pfaffian state for the half-filled Landau level. It is shown that for a wide
range of experimentally relevant inter-electron interactions the groundstate
can be very accurately represented in this form.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:52:05 GMT"
}
] | 2008-02-21T00:00:00 | [
[
"Moller",
"Gunnar",
""
],
[
"Simon",
"Steven H.",
""
]
] |
0708.2681 | Mikhail Kononenko | M.M. Kononenko | Super-light electromagnetic wave with longitudinal and transversal modes | 12 pages, 1 figure | null | null | null | physics.gen-ph | null | The transformation converting equations invariant under Lorentz into the
equations invariant under Galileo is obtained. On this basis: (1) the
super-light electromagnetic wave with longitudinal and transversal modes is
found out; (2) it is shown the wave velocity coincides with that of de
Broglie's wave; (3) the connection between Maxwell's electrodynamics and
Shredinger's equation is established; (4) structural elements of space are
discovered and "a horizon of visibility" is found. It is shown Bell's
inequalities and the principle of the light speed constancy are based on the
SRT artifact and "Einstein's local realism" is determined by the wave referred
above. Objectivity of results for quantum and classical objects is discussed
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:21:03 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Kononenko",
"M. M.",
""
]
] |
0708.2682 | Mark Westmoquette | M.S. Westmoquette, L.J. Smith, J.S. Gallagher III and K.M. Exter | Gemini GMOS/IFU spectroscopy of NGC 1569 - II: Mapping the roots of the
galactic outflow | 21 pages, 23 figures, 3 tables. Accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12252.x | null | astro-ph | null | We present a set of four Gemini-North GMOS/IFU observations of the central
disturbed regions of the dwarf irregular starburst galaxy NGC 1569, surrounding
the well-known super star clusters A and B. This continues on directly from a
companion paper, in which we describe the data reduction and analysis
techniques employed and present the analysis of one of the IFU pointings. By
decomposing the emission line profiles across the IFU fields, we map out the
properties of each individual component identified and identify a number of
relationships and correlations that allow us to investigate in detail the state
of the ionized ISM. Our observations support and expand on the main findings
from the analysis of the first IFU position, where we conclude that a broad (<
400 km/s) component underlying the bright nebular emission lines is produced in
a turbulent mixing layer on the surface of cool gas knots, set up by the impact
of the fast-flowing cluster winds. We discuss the kinematic, electron density
and excitation maps of each region in detail and compare our results to
previous studies. Our analysis reveals a very complex environment with many
overlapping and superimposed components, including dissolving gas knots,
rapidly expanding shocked shells and embedded ionizing sources, but no evidence
for organised bulk motions. We conclude that the four IFU positions presented
here lie well within the starburst region where energy is injected, and, from
the lack of substantial ordered gas flows, within the quasi-hydrostatic zone of
the wind interior to the sonic point. The net outflow occurs at radii beyond
100-200 pc, but our data imply that mass-loading of the hot ISM is active even
at the roots of the wind.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:21:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Westmoquette",
"M. S.",
""
],
[
"Smith",
"L. J.",
""
],
[
"Gallagher",
"J. S.",
"III"
],
[
"Exter",
"K. M.",
""
]
] |
0708.2683 | Jesse Johnson | Jesse Johnson | Automorphisms of the three-torus preserving a genus three Heegaard
splitting | 21 pages, 7 figures | null | null | null | math.GT | null | The mapping class group of a Heegaard splitting is the group of connected
components in the set of automorphisms of the ambient manifold that map the
Heegaard surface onto itself. For the genus three Heegaard splitting of the
3-torus, we find an eight element generating set for this group. Six of these
generators induce generating elements of the mapping class group of the 3-torus
and the remaining two are isotopy trivial in the 3-torus.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:23:27 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Johnson",
"Jesse",
""
]
] |
0708.2684 | Dima Khavinson | C. D. Fassnacht, C. R. Keeton and D. Khavinson | Gravitational lensing by Elliptical Galaxies, and the Schwarz Function | 16 pages, 7 figures based on a pleanry talk at the international
conference on analysis and mathematical physics "New Trends in Complex and
Harmonic Analysis", May 7 - 12, 2007, Voss, Norway | null | null | null | math-ph astro-ph math.CV math.MP | null | We discuss gravitational lensing by elliptical galaxies with some particular
mass distributions. Using simple techniques from the theory of quadrature
domains and the Schwarz function (cf. \cite{Sh}) we show that when the mass
density is constant on confocal ellipses, the total number of lensed images of
a point source cannot exceed 5 (4 bright images and 1 dim image). Also, using
the Dive--Nikliborc converse of the celebrated Newton's theorem concerning the
potentials of ellipsoids, we show that ``Einstein rings'' must always be either
circles (in the absence of a tidal shear), or ellipses.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:12:25 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Fassnacht",
"C. D.",
""
],
[
"Keeton",
"C. R.",
""
],
[
"Khavinson",
"D.",
""
]
] |
0708.2685 | Sebastian Burciu M | S. Burciu | A class of quantum doubles which are ribbon algebras | Some details are added. Corollary 2.4 and the remark after it are
reformulated. Section 4 with a general tareatment is added. References are
updated | null | null | null | math.RA math.QA | null | Andruskiewitsch and Schneider classify a large class of pointed Hopf algebras
with abelian coradical. The quantum double of each such Hopf algebra is
investigated. The quantum doubles of a family of Hopf algebras from the above
classification are ribbon Hopf algebras.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:35:54 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 14:31:56 GMT"
},
{
"version": "v3",
"created": "Tue, 11 Dec 2007 09:54:38 GMT"
}
] | 2007-12-11T00:00:00 | [
[
"Burciu",
"S.",
""
]
] |
0708.2686 | Darko Roglic | D. Roglic | The universal evolutionary computer based on super-recursive algorithms
of evolvability | 7 pages, 1 table, 1 figure | null | null | null | cs.NE | null | This work exposes which mechanisms and procesess in the Nature of evolution
compute a function not computable by Turing machine. The computer with
intelligence that is not higher than one bacteria population could have, but
with efficency to solve the problems that are non-computable by Turing machine
is represented. This theoretical construction is called Universal Evolutinary
Computer and it is based on the superecursive algorithms of evolvability.
| [
{
"version": "v1",
"created": "Tue, 24 Jul 2007 18:50:22 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Roglic",
"D.",
""
]
] |
0708.2687 | Stephan Gift PhD | Stephan J. G. Gift | Light Speed Invariance is a Remarkable Illusion | 12 pages, 2 figures | null | null | null | physics.gen-ph | null | Though many experiments appear to have confirmed the light speed invariance
postulate of special relativity theory, this postulate is actually unverified.
This paper resolves this issue by first showing the manner in which an illusion
of light speed invariance occurs in two-way light speed measurement in the
framework of a semi-classical absolute space theory. It then demonstrates a
measurable variation of the one-way speed of light, which directly invalidates
the invariance postulate and confirms the existence of the preferred reference
frame of the absolute space theory.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:50:23 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Gift",
"Stephan J. G.",
""
]
] |
0708.2688 | Jerzy Blawzdziewicz | M. Baron, J. Blawzdziewicz, E. Wajnryb | Hydrodynamic crystals: collective dynamics of regular arrays of
spherical particles in a parallel-wall channel | 4 pages 6 figures | Phys. Rev. Lett. 100, Art. No .174502 (2008) | 10.1103/PhysRevLett.100.174502 | null | cond-mat.soft | null | Simulations of over $10^3$ hydrodynamically coupled solid spheres are
performed to investigate collective motion of linear trains and regular square
arrays of particles suspended in a fluid bounded by two parallel walls. Our
novel accelerated Stokesian-dynamics algorithm relies on simplifications
associated with the Hele--Shaw asymptotic far-field form of the flow scattered
by the particles. The simulations reveal propagation of particle-displacement
waves, deformation and rearrangements of a particle lattice, propagation of
dislocation defects in ordered arrays, and long-lasting coexistence of ordered
and disordered regions.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:58:52 GMT"
},
{
"version": "v2",
"created": "Fri, 15 Feb 2008 12:00:49 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Apr 2008 00:56:50 GMT"
}
] | 2008-04-29T00:00:00 | [
[
"Baron",
"M.",
""
],
[
"Blawzdziewicz",
"J.",
""
],
[
"Wajnryb",
"E.",
""
]
] |
0708.2689 | Ikuko Hamamoto | Ikuko Hamamoto | Nilsson diagrams for light neutron-rich nuclei with weakly-bound
neutrons | 12 pages, 5 figures | Phys.Rev.C76:054319,2007 | 10.1103/PhysRevC.76.054319 | null | nucl-th | null | Using Woods-Saxon potentials and the eigenphase formalism for one-particle
resonances, one-particle bound and resonant levels for neutrons as a function
of quadrupole deformation are presented, which are supposed to be useful for
the interpretation of spectroscopic properties of some light neutron-rich
nuclei with weakly-bound neutrons. Compared with Nilsson diagrams in text books
which are constructed using modified oscillator potentials, we point out a
systematic change of the shell structure in connection with both weakly-bound
and resonant one-particle levels related to small orbital angular momenta
$\ell$. Then, it is seen that weakly-bound neutrons in nuclei such as
$^{15-19}$C and $^{33-37}$Mg may prefer to being deformed as a result of
Jahn-Teller effect, due to the near degeneracy of the 1d$_{5/2}$-2s$_{1/2}$
levels and the 1f$_{7/2}$-2p$_{3/2}$ levels in the spherical potential,
respectively. Furthermore, the absence of some one-particle resonant levels
compared with the Nilsson diagrams in text books is illustrated.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:01:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hamamoto",
"Ikuko",
""
]
] |
0708.2690 | Muhammad Sharif | M. Sharif and Umber Sheikh | Effects of Schwarzschild Black Hole Horizon on Isothermal Plasma Wave
Dispersion | 23 pages, 8 figures accepted for publication in Gen. Relat. Grav | Gen.Rel.Grav.39:2095-2124,2007 | 10.1007/s10714-007-0505-4 | null | gr-qc astro-ph | null | The 3+1 GRMHD equations for Schwarzschild spacetime in Rindler coordinates
with isothermal state of plasma are formulated. We consider the cases of
non-rotating and rotating backgrounds with non-magnetized and magnetized
plasmas. For these cases, the perturbed form of these equations are linearized
and Fourier analyzed by introducing plane wave type solutions. The determinant
of these equations in each case leads to two dispersion relations which give
value of the wave number $k$. Using the wave number, we obtain information like
phase and group velocities etc. which help to discuss the nature of the waves
and their characteristics. These provide interesting information about the
black hole magnetosphere near the horizon. There are cases of normal and
anomalous dispersion. We find a case of normal dispersion of waves when the
plasma admits the properties of Veselago medium. Our results agree with those
of Mackay et al. according to which rotation of a black hole is required for
negative phase velocity propagation.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 12:42:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sharif",
"M.",
""
],
[
"Sheikh",
"Umber",
""
]
] |
0708.2691 | Stuart Raby | Oleg Lebedev, Hans Peter Nilles, Stuart Raby, Saul Ramos-Sanchez,
Michael Ratz, Patrick K. S. Vaudrevange, Akin Wingerter | The Heterotic Road to the MSSM with R parity | 61 pages, 2 figures | Phys.Rev.D77:046013,2008 | 10.1103/PhysRevD.77.046013 | CERN-PH-TH/2007-126, OHSTPY-HEP-T-07-003, TUM-HEP-673/07 | hep-th hep-ph | null | In a previous paper, referred to as a "Mini-Landscape" search, we explored a
"fertile patch" of the heterotic landscape based on a Z6-II orbifold with
SO(10) and E6 local GUT structures. In the present paper we extend this
analysis. We find many models with the minimal supersymmetric standard model
spectra and an exact R parity. In all of these models, the vector-like exotics
decouple along D flat directions. We present two "benchmark" models which
satisfy many of the constraints of a realistic supersymmetric model, including
non-trivial Yukawa matrices for 3 families of quarks and leptons and Majorana
neutrino masses for right-handed neutrinos with non-trivial See-Saw masses for
the 3 light neutrinos. In an appendix we comment on the important issue of
string selection rules and in particular the so-called "gamma-rule".
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:09:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lebedev",
"Oleg",
""
],
[
"Nilles",
"Hans Peter",
""
],
[
"Raby",
"Stuart",
""
],
[
"Ramos-Sanchez",
"Saul",
""
],
[
"Ratz",
"Michael",
""
],
[
"Vaudrevange",
"Patrick K. S.",
""
],
[
"Wingerter",
"Akin",
""
]
] |
0708.2692 | Sergey Sevbitov | T. V. Shishkina | Search for effects beyond Standard Model in photon scatterings and in
nonminimal gauge theories on linear colliders of new generation | 20 pages, 18 figures, LaTeX | null | null | null | hep-ph | null | The main possibilities of investigation of leptons and bosons production in
interaction of polarized photons are considered. The usage of $\gamma\gamma\to
f\bar{f}[+\gamma]$ reactions for the luminosity measurement on linear photon
collider is analyzed. The achievable precision of the luminosity measuring is
considered and calculated. The first-order QED correction to $\gamma\gamma\to
l\bar{l}$ scattering is analyzed. All possible polarization states of
interacting particles are investigated. For the detection of deviations from SM
predictions at linear $\gamma\gamma$ colliders with center of mass energies
running to 1 TeV the influence of three possible anomalous couplings on the
cross sections of $W^+W^-$ productions has been investigated. The significant
discrimination between various anomalous contributions is discovered. The main
contribution of high order electroweak effects is considered.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:44:26 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Shishkina",
"T. V.",
""
]
] |
0708.2693 | Nils Andersson | K. Glampedakis, N. Andersson and D. I. Jones | On the stability of precessing superfluid neutron stars | 4 pages, Revtex, 1 eps figure | Phys.Rev.Lett.100:081101,2008 | 10.1103/PhysRevLett.100.081101 | null | astro-ph | null | We discuss a new superfluid instability occuring in the interior of mature
neutron stars with implications for freely precessing neutron stars. This
short-wavelength instability is similar to the instability which is responsible
for the formation of turbulence in superfluid Helium. Its existence raises
serious questions about our understanding of neutron star precession and
complicates attempts to constrain neutron star interiors using such
observations.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:07:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Glampedakis",
"K.",
""
],
[
"Andersson",
"N.",
""
],
[
"Jones",
"D. I.",
""
]
] |
0708.2694 | Vadim. Ya. Pokrovskii | V. Ya. Pokrovskii and S. G. Zybtsev | Self-sensitive torsional microresonators based on a charge-density wave
system | 10 pages including 3 figures | null | null | null | cond-mat.str-el cond-mat.mtrl-sci | null | Recently, there have been dramatic advances in the miniaturization of
electromechanical devices. Most of the micro- and nanoelectromechanical systems
(MEMS-NEMS) operate in the resonant modes1. The micron-, and, the more, the
submicron-sizes devices, are driven usually by electrostatic forces, as
piezoelectric and electromagnetic engines are powerless over this size range.
Such engines could play the role of external actuators for the NEMS, being,
however, macro devices in their own. Apart from actuation, an objective of NEMS
is getting the output signal characterizing the oscillations1, so, actuators
sensing their own motion are rather topical (see 2 for example). Not long ago,
several works appeared demonstrating high sensitivity of the sizes3,4 and form5
of quasi one-dimensional conductors to the deformations of the charge-density
wave (CDW). Here we demonstrate electrically driven torsional resonators based
on whiskers of the quasi one-dimensional conductor with CDW, TaS3. The driving
force for the torsional deformation is peculiar to the CDW systems and reflects
the transmission of the CDW deformation to the crystalline lattice. In
comparison with the piezoelectrics, the effect of electric field on the crystal
deformation is 3-4 orders of magnitude larger. The resonator is found to
provide also a torsion-induced electrical feed-back (output signal) from the
oscillations. We discuss the CDW systems as promising elements for NEMS-MEMS.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:17:21 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Pokrovskii",
"V. Ya.",
""
],
[
"Zybtsev",
"S. G.",
""
]
] |
0708.2695 | Yuri Kovalev Jr. | Y. Y. Kovalev (MPIfR & ASC Lebedev), M. L. Lister (Purdue U.), D. C.
Homan (Denison U.), K. I. Kellermann (NRAO) | The Inner Jet of the Radio Galaxy M87 | 4 pages, 2 color figures, 1 table, accepted for publication in the
Astrophysical Journal Letters; a typo in a reference has been corrected | Astroph.J.Lett. 668 (2007), 27-30 | 10.1086/522603 | null | astro-ph | null | We report new 2 cm VLBA images of the inner radio jet of M87 showing a limb
brightened structure and unambiguous evidence for a faint 3 mas long
counter-feature which also appears limb brightened. Multi-epoch observations of
seven separate jet features show typical speeds of less than a few percent of
the speed of light, despite the highly asymmetric jet structure and the
implications of the canonical relativistic beaming scenario. The observed
morphology is consistent with a two stream spine-sheath velocity gradient
across the jet, as might be expected from the recently discovered strong and
variable TeV emission as well as from numerical modeling of relativistic jets.
Considering the large jet to counter-jet flux density ratio and lack of
observed fast motion in the jet, we conclude that either the inner part of the
M87 jet is intrinsically asymmetric or that the bulk plasma flow speed is much
greater than any propagation of shocks or other pattern motions.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 15:35:21 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 12:49:53 GMT"
}
] | 2007-09-29T00:00:00 | [
[
"Kovalev",
"Y. Y.",
"",
"MPIfR & ASC Lebedev"
],
[
"Lister",
"M. L.",
"",
"Purdue U."
],
[
"Homan",
"D. C.",
"",
"Denison U."
],
[
"Kellermann",
"K. I.",
"",
"NRAO"
]
] |
0708.2696 | Uro\v{s} Kosti\'c | A. Cadez, M. Calvani, A. Gomboc, U. Kostic | Do flares in Sagittarius A* reflect the last stage of tidal capture? | 6 pages, 9 figures, acknowledgments added, to appear in the
Proceedings of the Albert Einstein's Century International Conference, Paris
2005 | AIPConf.Proc.861:566-571,2006 | 10.1063/1.2399625 | null | astro-ph | null | In recent years the case for the presence of 3-4 10^6 M_sun black hole in our
Galactic Center has gained strength from results of stellar dynamics
observations and from the detection of several rapid X-ray and IR flares
observed in the Sagittarius A* from 2000 to 2004. Here we explore the idea that
such flares are produced when the central black hole tidally captures and
disrupts a small body - e.g. a comet or an asteroid.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:18:54 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 14:14:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cadez",
"A.",
""
],
[
"Calvani",
"M.",
""
],
[
"Gomboc",
"A.",
""
],
[
"Kostic",
"U.",
""
]
] |
0708.2697 | Hugh Osborn | J. O'Dwyer and H. Osborn | Epsilon Expansion for Multicritical Fixed Points and Exact
Renormalisation Group Equations | 40 pages, 12 figures version2: small corrections, extra references,
final appendix rewritten, version3: some corrections to perturbative
calculations | Annals Phys.323:1859-1898,2008 | 10.1016/j.aop.2007.10.005 | DAMTP 07/77 | hep-th cond-mat.other | http://creativecommons.org/publicdomain/zero/1.0/ | The Polchinski version of the exact renormalisation group equations is
applied to multicritical fixed points, which are present for dimensions between
two and four, for scalar theories using both the local potential approximation
and its extension, the derivative expansion. The results are compared with the
epsilon expansion by showing that the non linear differential equations may be
linearised at each multicritical point and the epsilon expansion treated as a
perturbative expansion. The results for critical exponents are compared with
corresponding epsilon expansion results from standard perturbation theory. The
results provide a test for the validity of the local potential approximation
and also the derivative expansion. An alternative truncation of the exact RG
equation leads to equations which are similar to those found in the derivative
expansion but which gives correct results for critical exponents to order
$\epsilon$ and also for the field anomalous dimension to order $\epsilon^2$. An
exact marginal operator for the full RG equations is also constructed.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:02:11 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 14:07:41 GMT"
},
{
"version": "v3",
"created": "Fri, 29 May 2020 14:30:46 GMT"
}
] | 2020-06-01T00:00:00 | [
[
"O'Dwyer",
"J.",
""
],
[
"Osborn",
"H.",
""
]
] |
0708.2698 | Diego Dominici | Diego Dominici | Fisher information of orthogonal polynomials I | 12 pages | null | null | null | math.CA | null | Following the lead of J. Dehesa and his collaborators, we compute the Fisher
information of the Meixner-Pollaczek, Meixner, Krawtchouk and Charlier
polynomials.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:03:27 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Dominici",
"Diego",
""
]
] |
0708.2699 | J. Brian Conrey | J. Brian Conrey | The mean-square of Dirichlet L-functions | null | null | null | AIM preprint number 2007-54 | math.NT | null | We verify the conjecture of [CFKRS] for the mean square near the critical
point of Dirichlet L-functions for a composite modulus q. We also prove a kind
of reciprocity formula when the second moment for a prime modulus is twisted by
a character evaluated at a different prime.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:19:41 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Conrey",
"J. Brian",
""
]
] |
0708.2700 | Vadim. Ya. Pokrovskii | V. Ya. Pokrovskii | On the Enormous Effect of Electric Field on the Crystalline Lattice of
the Conductors with Charge-Density Waves | 4 pages | Pis'ma ZhETF vol. 86, issue 4, page 290-293 (August 2007) | 10.1134/S0021364007160096 | null | cond-mat.str-el | null | We discuss deformation of quasi 1-dimensional conductors with charge-density
wave (CDW) under the electric field deforming the CDW. In case of ``strong''
CDW-lattice interaction the effect can be treated in terms of the converse
piezoelectric effect with enormous piezomodulus, $\sim L_c/\lambda$ times
larger than that in ionic crystals ($\lambda$ is the CDW wavelength, $L_c$ is
the CDW coherence length, mm scale in the sliding state). The CDW-lattice
interaction is likely to be defined by the interband charge transfer
(rearrangement of the covalent bonds) with lattice deformation, possible in a
number of CDW compounds. The resulting effects, observed or expected, are
paving a way towards new-principle actuators, including nanosized ones.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:27:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pokrovskii",
"V. Ya.",
""
]
] |
0708.2701 | Brent D. Nelson | Junhai Kang, Paul Langacker and Brent D. Nelson | Theory and Phenomenology of Exotic Isosinglet Quarks and Squarks | Two additional references added | Phys.Rev.D77:035003,2008 | 10.1103/PhysRevD.77.035003 | null | hep-ph hep-ex | null | Extensions of the MSSM often predict the existence of new fermions and their
scalar superpartners which are vectorlike with respect to the standard model
gauge group but may be chiral under additional gauge factors. In this paper we
explore the production and decay of an important example, i.e., a heavy
isosinglet charge -1/3 quark and its scalar partner, using the charge
assignments of a 27-plet of E6 for illustration. We emphasize that, depending
on the symmetries of the low energy theory, such exotic particles may decay by
the mixing of the fermion with the d, s, or b quarks; may decay by leptoquark
or diquark couplings (which may nevertheless preserve a form of R-parity); or
may be stable with respect to renormalizable couplings but decay by
higher-dimension operators on cosmological times scales. We discuss the latter
two possibilities in detail for various assumptions concerning the relative
masses of the exotic fermions, scalars, and the lightest neutralino, and
emphasize the necessity of considering the collider signatures in conjunction
with the normal MSSM processes. Existing and projected constraints from
colliders, indirect experiments, proton decay, and big bang nucleosynthesis are
considered.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:36:19 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 21:53:50 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kang",
"Junhai",
""
],
[
"Langacker",
"Paul",
""
],
[
"Nelson",
"Brent D.",
""
]
] |
0708.2702 | Ali Dariush | Ali Dariush, Habib G. Khosroshahi, Trevor J. Ponman, Frazer Pearce,
Somak Raychaudhury, Will Hartley | The Mass Assembly of Fossil Groups of Galaxies in the Millennium
Simulation | 11 pages, 8 figures, submitted to MNRAS | MNRAS (2007), 382, 433 | 10.1111/j.1365-2966.2007.12385.x | null | astro-ph | null | The evolution of present-day fossil galaxy groups is studied in the
Millennium Simulation. Using the corresponding Millennium gas simulation and
semi-analytic galaxy catalogues, we select fossil groups at redshift zero
according to the conventional observational criteria, and trace the haloes
corresponding to these groups backwards in time, extracting the associated dark
matter, gas and galaxy properties. The space density of the fossils from this
study is remarkably close to the observed estimates and various possibilities
for the remaining discrepancy are discussed. The fraction of X-ray bright
systems which are fossils appears to be in reasonable agreement with
observation, and the simulations predict that fossil systems will be found in
significant numbers (3-4% of the population) even in quite rich clusters. We
find that fossils assemble a higher fraction of their mass at high redshift,
compared to non-fossil groups, with the ratio of the currently assembled halo
mass to final mass, at any epoch, being about 10 to 20% higher for fossils.
This supports the paradigm whereby fossils represent undisturbed, early-forming
systems in which large galaxies have merged to form a single dominant
elliptical.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:41:09 GMT"
},
{
"version": "v2",
"created": "Thu, 22 May 2008 18:04:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dariush",
"Ali",
""
],
[
"Khosroshahi",
"Habib G.",
""
],
[
"Ponman",
"Trevor J.",
""
],
[
"Pearce",
"Frazer",
""
],
[
"Raychaudhury",
"Somak",
""
],
[
"Hartley",
"Will",
""
]
] |
0708.2703 | Catherine Garland | C. A. Garland, D. J. Pisano, J. P. Williams, R. Guzman, F. J.
Castander, L. J. Sage | The Nature of Nearby Counterparts to Intermediate-Redshift Luminous
Compact Blue Galaxies. III. Interferometric Observations of Neutral Atomic
and Molecular Gas | Accepted by ApJ 8/15/07 | null | 10.1086/522514 | null | astro-ph | null | We present the results of a VLA and OVRO-MMA follow-up to our single-dish
surveys of the neutral atomic and molecular gas in a sample of nearby Luminous
Compact Blue Galaxies (LCBGs). These luminous, blue, high surface brightness,
starbursting galaxies were selected using criteria similar to that used to
define LCBGs at higher redshifts. The surveys were undertaken to study the
nature and evolutionary possibilities of LCBGs, using dynamical masses and gas
depletion time scales as constraints. Here we present nearly resolved VLA H I
maps of four LCBGs, as well as results from the literature for a fifth LCBG. In
addition, we present OVRO-MMA maps of CO(J=1-0) in two of these LCBGs. We have
used the resolved H I maps to separate the H I emission from target galaxies
and their companions to improve the accuracy of our gas and dynamical mass
estimates. For this sub-sample of LCBGs, we find that the dynamical masses
measured with the single-dish telescope and interferometer are in agreement.
However, we find that we have overestimated the mass of H I in two galaxies by
a significant amount, possibly as much as 75%, when compared to the single-dish
estimates. These two galaxies have companions within a few arc minutes; we find
that our single-dish and interferometric measurements of H I masses are in
reasonable agreement for galaxies with more distant companions. The H I
velocity fields indicate that all five galaxies are clearly rotating yet
distorted, likely due to recent interactions. Our measurements of the gas and
dynamical masses of LCBGs point towards evolution into low mass galaxies such
as dwarf ellipticals, irregulars, and low mass spirals, consistent with studies
of LCBGs at higher redshifts.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:42:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Garland",
"C. A.",
""
],
[
"Pisano",
"D. J.",
""
],
[
"Williams",
"J. P.",
""
],
[
"Guzman",
"R.",
""
],
[
"Castander",
"F. J.",
""
],
[
"Sage",
"L. J.",
""
]
] |
0708.2704 | Waheb Bishara | Waheb Bishara, Chetan Nayak | Edge States and Interferometers in the Pfaffian and anti-Pfaffian States | 8 pages, 3 figures. Fixed typos, added refs 32-33 | Phys. Rev. B 77, 165302 (2008) | 10.1103/PhysRevB.77.165302 | null | cond-mat.mes-hall cond-mat.str-el | null | We compute the tunneling current in a double point contact geometry of a
Quantum Hall system at filling fraction $\nu=5/2$, as function of voltage and
temeprature, in the weak tunneling regime. We quantitatively compare two
possible candidates for the state at $\nu=5/2$: the Moore-Read Pfaffian state,
and its particle-hole conjugate, the anti-Pfaffian. We find that both
possibilities exhibit the same qualitative behavior, and both have an even-odd
effect that reflects their non-Abelian nature, but differ quantitatively in
their voltage and temperature dependance.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:48:07 GMT"
},
{
"version": "v2",
"created": "Sat, 15 Dec 2007 01:16:37 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Apr 2008 16:36:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bishara",
"Waheb",
""
],
[
"Nayak",
"Chetan",
""
]
] |
0708.2705 | Sharon Hollander | Sharon Hollander | Characterizing algebraic stacks | 12 pages, to appear in Proc. Amer. Math. Soc | null | null | null | math.AT math.CT | null | We extend the notion of algebraic stack to an arbitrary subcanonical site C.
If the topology on C is local on the target and satisfies descent for
morphisms, we show that algebraic stacks are precisely those which are weakly
equivalent to representable presheaves of groupoids whose domain map is a
cover. This leads naturally to a definition of algebraic n-stacks. We also
compare different sites naturally associated to a stack.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 17:51:00 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Hollander",
"Sharon",
""
]
] |
0708.2706 | Michael Thoennessen | N. Frank, A. Schiller, T. Baumann, D. Bazin, J. Brown, P. A. DeYoung,
J. E. Finck, A. Gade, J. Hinnefeld, R. Howes, J.-L. Lecouey, B. Luther, W. A.
Peters, H. Scheit and M. Thoennessen | Observation of the First Excited State in 23O | 7 pages, 3 figures, Proc. 23rd Winter Workshop on Nuclear Dynamics,
February 11-18, 2007 | null | null | null | nucl-ex | null | The first excited state in neutron-rich 23O was observed in a (2p1n)
knock-out reaction from 26Ne on a beryllium target at a beam energy of 86
MeV/A. The state is unbound with respect to neutron emission and was
reconstructed from the invariant mass from the 22O fragment and the neutron. It
is unbound by 45(2) keV corresponding to an excitation energy of 2.8(1) MeV.
The non-observation of further resonances implies a predominantly direct
reaction mechanism of the employed three-nucleon-removal reaction which
suggests the assignment of the observed resonance to be the 5/2+ hole state.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 18:06:04 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Frank",
"N.",
""
],
[
"Schiller",
"A.",
""
],
[
"Baumann",
"T.",
""
],
[
"Bazin",
"D.",
""
],
[
"Brown",
"J.",
""
],
[
"DeYoung",
"P. A.",
""
],
[
"Finck",
"J. E.",
""
],
[
"Gade",
"A.",
""
],
[
"Hinnefeld",
"J.",
""
],
[
"Howes",
"R.",
""
],
[
"Lecouey",
"J. -L.",
""
],
[
"Luther",
"B.",
""
],
[
"Peters",
"W. A.",
""
],
[
"Scheit",
"H.",
""
],
[
"Thoennessen",
"M.",
""
]
] |
0708.2707 | Peter Csermely | Shijun Wang, Mate S. Szalay, Changshui Zhang, Peter Csermely | Learning and innovative elements of strategy adoption rules expand
cooperative network topologies | 14 pages, 3 Figures + a Supplementary Material with 25 pages, 3
Tables, 12 Figures and 116 references | PLoS ONE 3, e1917 (2008) | 10.1371/journal.pone.0001917 | null | q-bio.MN cond-mat.dis-nn nlin.AO physics.bio-ph | null | Cooperation plays a key role in the evolution of complex systems. However,
the level of cooperation extensively varies with the topology of agent networks
in the widely used models of repeated games. Here we show that cooperation
remains rather stable by applying the reinforcement learning strategy adoption
rule, Q-learning on a variety of random, regular, small-word, scale-free and
modular network models in repeated, multi-agent Prisoners Dilemma and Hawk-Dove
games. Furthermore, we found that using the above model systems other long-term
learning strategy adoption rules also promote cooperation, while introducing a
low level of noise (as a model of innovation) to the strategy adoption rules
makes the level of cooperation less dependent on the actual network topology.
Our results demonstrate that long-term learning and random elements in the
strategy adoption rules, when acting together, extend the range of network
topologies enabling the development of cooperation at a wider range of costs
and temptations. These results suggest that a balanced duo of learning and
innovation may help to preserve cooperation during the re-organization of
real-world networks, and may play a prominent role in the evolution of
self-organizing, complex systems.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 16:56:46 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Apr 2008 12:32:08 GMT"
}
] | 2012-03-01T00:00:00 | [
[
"Wang",
"Shijun",
""
],
[
"Szalay",
"Mate S.",
""
],
[
"Zhang",
"Changshui",
""
],
[
"Csermely",
"Peter",
""
]
] |
0708.2708 | Michael Thoennessen | N. Frank, T. Baumann, D. Bazin, A. Gade, J.-L. Lecouey, W. A. Peters,
H. Scheit, A. Schiller, M. Thoennessen, J. Brown, P. A. DeYoung, J. E. Finck,
J. Hinnefeld, R. Howes, B. Luther | Population of neutron unbound states via two-proton knockout reactions | 6 pages, 3 figures, Proc. 9th Int. Spring Seminar on Nucl. Phys.
Changing Facets of Nuclear Structure, May 20-34, 2007 | null | 10.1142/9789812779038_0003 | null | nucl-ex | null | The two-proton knockout reaction 9Be(26Ne,O2p) was used to explore excited
unbound states of 23O and 24O. In 23O a state at an excitation energy of
2.79(13) MeV was observed. There was no conclusive evidence for the population
of excited states in 24O.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 18:24:14 GMT"
}
] | 2017-08-23T00:00:00 | [
[
"Frank",
"N.",
""
],
[
"Baumann",
"T.",
""
],
[
"Bazin",
"D.",
""
],
[
"Gade",
"A.",
""
],
[
"Lecouey",
"J. -L.",
""
],
[
"Peters",
"W. A.",
""
],
[
"Scheit",
"H.",
""
],
[
"Schiller",
"A.",
""
],
[
"Thoennessen",
"M.",
""
],
[
"Brown",
"J.",
""
],
[
"DeYoung",
"P. A.",
""
],
[
"Finck",
"J. E.",
""
],
[
"Hinnefeld",
"J.",
""
],
[
"Howes",
"R.",
""
],
[
"Luther",
"B.",
""
]
] |
0708.2709 | Mark Newman | M. E. J. Newman and Gourab Ghoshal | Bicomponents and the robustness of networks to failure | 5 pages, 1 figure, 1 table | Phys. Rev. Lett. 100, 138701 (2008) | 10.1103/PhysRevLett.100.138701 | null | cond-mat.stat-mech cond-mat.dis-nn | null | A common definition of a robust connection between two nodes in a network
such as a communication network is that there should be at least two
independent paths connecting them, so that the failure of no single node in the
network causes them to become disconnected. This definition leads us naturally
to consider bicomponents, subnetworks in which every node has a robust
connection of this kind to every other. Here we study bicomponents in both real
and model networks using a combination of exact analytic techniques and
numerical methods. We show that standard network models predict there to be
essentially no small bicomponents in most networks, but there may be a giant
bicomponent, whose presence coincides with the presence of the ordinary giant
component, and we find that real networks seem by and large to follow this
pattern, although there are some interesting exceptions. We study the size of
the giant bicomponent as nodes in the network fail, using a specially developed
computer algorithm based on data trees, and find in some cases that our
networks are quite robust to failure, with large bicomponents persisting until
almost all vertices have been removed.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 22:07:00 GMT"
}
] | 2008-04-07T00:00:00 | [
[
"Newman",
"M. E. J.",
""
],
[
"Ghoshal",
"Gourab",
""
]
] |
0708.2710 | Mark Hamilton | Mark D. Hamilton | The quantization of a toric manifold is given by the integer lattice
points in the moment polytope | 10 pages, LaTeX, 3 figures; v2 minor changes: some small
clarifications added, typos fixed. To appear in proceedings of 2006
International Toric Topology Conference | null | null | null | math.SG | null | We describe a very nice argument, which we learned from Sue Tolman, that the
dimension of the quantization space of a toric manifold, using a Kaehler
polarization, is given by the number of integer lattice points in the moment
polytope.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 19:31:58 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Feb 2008 19:59:26 GMT"
}
] | 2008-02-13T00:00:00 | [
[
"Hamilton",
"Mark D.",
""
]
] |
0708.2711 | Agnieszka Janiuk | Agnieszka Janiuk, Daniel Proga (UNLV) | Low angular momentum accretion in the collapsar: how long can a long GRB
be? | 29 pages, 10 figures, including 1 color fig., revised version
accepted by ApJ | null | 10.1086/526511 | null | astro-ph | null | The collapsar model is the most promising scenario to explain the huge
release of energy associated with long duration gamma-ray-bursts (GRBs). Within
this scenario GRBs are believed to be powered by accretion through a
rotationally support torus or by fast rotation of a compact object. In both
cases then, rotation of the progenitor star is one of the key properties
because it must be high enough for the torus to form, the compact object to
rotate very fast, or both. Here, we check what rotational properties a
progenitor star must have in order to sustain torus accretion over relatively
long activity periods as observed in most GRBs. We show that simple, often
cited, estimates of the total mass available for torus formation and
consequently the duration of a GRB are only upper limits. We revise these
estimates by taking into account the long term effect that as the compact
object accretes the minimum specific angular momentum needed for torus
formation increases. This in turn leads to a smaller fraction of the stellar
envelope that can form a torus. We demostrate that this effect can lead to a
significant, an order of magnidute, reduction of the total energy and overall
duration of a GRB event. This of course can be mitigated by assuming that the
progenitor star rotates faster then we assumed. However, our assumed rotation
is already high compared to observational and theoretical constraints. We also
discuss implications of our result.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 22:15:50 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 11:45:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Janiuk",
"Agnieszka",
"",
"UNLV"
],
[
"Proga",
"Daniel",
"",
"UNLV"
]
] |
0708.2712 | Ronnie Jansson | Ronnie Jansson, Glennys R. Farrar | Maximum Likelihood method for ultrahigh energy cosmic ray cross
correlations with astrophysical sources | 4 pages, 4 figures, proceedings of the 30th ICRC, Merida, Mexico 2007 | null | null | null | astro-ph | null | We extend the Maximum Likelihood method used by HiRes to study cross
correlations between a catalog of candidate astrophysical sources and Ultrahigh
Energy Cosmic Rays (UHECRs), to allow for differing source luminosities. Our
approach permits individual sources to be ranked according to their likelihood
of having emitted the correlated UHECRs. We test both old and new method by
simulations for various scenarios. We conclude that there are 9 true
correlation between HiRes UHECRs and known BLLacs, with a 6*10^-5 probability
of such a correlation arising by chance.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 22:37:46 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Jansson",
"Ronnie",
""
],
[
"Farrar",
"Glennys R.",
""
]
] |
0708.2713 | Asterios Pantokratoras | Asterios Pantokratoras | Comment on "Radiative effect on natural convection flows in porous
media, A.A. Mohammadein, M. A. Mansour, Sahar M. Abd El Gaied and Rama Subba
Reddy Gorla [Transport in Porous Media 32:263-283, 1998]" | 4 pages, 1 figure | null | null | null | physics.flu-dyn | null | In the above paper the authors treat the natural convection boundary layer
flow in a Darcy-Brinkman-Forchheimer porous medium. In the energy equation the
radiation effect has been taken into account. A two-parameter perturbation
method is used for the solution of the equations. The first order results are
presented in tables and figures. This is an interesting work but there are some
weak points which are presented below:
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 22:48:38 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Pantokratoras",
"Asterios",
""
]
] |
0708.2714 | Ronnie Jansson | Ronnie Jansson, Glennys R. Farrar, Andre Waelkens, Torsten A. Ensslin | Large scale magnetic field of the Milky Way from WMAP3 data | 4 pages, 4 figures, proceedings of the 30th ICRC, Merida, Mexico 2007 | null | null | null | astro-ph | null | We report on initial results from a project to constrain the large-scale and
turbulent magnetic fields of the Milky Way galaxy, which eventually will
incorporate all of the relevant observational data. In this paper we fit
popular large scale magnetic field models to WMAP3 polarization maps. We find
that the polarization data can constrain certain model parameters but does not
uniquely determine the best-fit parameters. We also find that the polarization
data alone cannot distinguish between model symmetries, e.g., the existence of
field reversals. We show how future UHECR data can break this degeneracy.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 22:49:43 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Jansson",
"Ronnie",
""
],
[
"Farrar",
"Glennys R.",
""
],
[
"Waelkens",
"Andre",
""
],
[
"Ensslin",
"Torsten A.",
""
]
] |
0708.2715 | Samantha Santos | Samantha Fonseca dos Santos, Viatcheslav Kokoouline, and Chris H.
Greene | Dissociative recombination of H3+ in the ground and excited vibrational
states | 20 pages, 5 figures | null | null | null | physics.atom-ph | null | The article presents calculated dissociative recombination (DR) rate
coefficients for H+3 . The previous theoretical work on H+3 was performed using
the adiabatic hyperspherical approximation to calculate the target ion
vibrational states and it considered just a limited number of ionic rotational
states. In this study, we use accurate vibrational wave functions and a larger
number of possible rotational states of the H3+ ground vibrational level. The
DR rate coefficient obtained is found to agree better with the experimental
data from storage-ring experiments than the previous theoretical calculation.
We present evidence that excited rotational states could be playing an
important role in those experiments for collision energies above 10 meV. The DR
rate coefficients calculated separately for ortho- and para-H3+ are predicted
to differ significantly at low energy, a result consistent with a recent
experiment. We also present DR rate coefficients for vibrationally-excited
initial states of H3+, which are found to be somewhat larger than the rate
coefficient for the ground vibrational level.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 23:42:03 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Santos",
"Samantha Fonseca dos",
""
],
[
"Kokoouline",
"Viatcheslav",
""
],
[
"Greene",
"Chris H.",
""
]
] |
0708.2716 | Stephen Fegan | S. J. Fegan and V. V. Vassiliev | The performance of an idealized large-area array of moderate-sized IACTs | 4 pages, 3 figures, in Proc. 30th International Cosmic Ray
Conference, Merida, Mexico, 2007 | null | null | null | astro-ph | null | We present simulations of a large array of imaging atmospheric Cherenkov
telescopes (IACTs), for which the size of the array footprint is much larger
than the size of the Cherenkov lightpool. To evaluate limitations of the
imaging atmospheric Cherenkov technique, the array is simulated under the
assumption of ideal optics, having infinite resolution of the photon arrival
direction, which makes our conclusions independent of any particular telescope
implementation. The primary characteristics of the array performance, gamma-ray
trigger efficiency, photon energy at the peak of the detection rate, and
angular resolution are calculated as a function of the parameters of the array:
telescope spacing, telescope aperture, and camera pixelation. We discuss
implication of the results for the design of the next generation ground-based
gamma-ray observatory.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 23:53:15 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Fegan",
"S. J.",
""
],
[
"Vassiliev",
"V. V.",
""
]
] |
0708.2717 | Alejandro Vaisman Prof. | Leticia Gomez, Bart Kuijpers, Alejandro Vaisman | Aggregation Languages for Moving Object and Places of Interest Data | 15 pages, 5 figures | null | null | null | cs.DB | null | We address aggregate queries over GIS data and moving object data, where
non-spatial data are stored in a data warehouse. We propose a formal data model
and query language to express complex aggregate queries. Next, we study the
compression of trajectory data, produced by moving objects, using the notions
of stops and moves. We show that stops and moves are expressible in our query
language and we consider a fragment of this language, consisting of regular
expressions to talk about temporally ordered sequences of stops and moves. This
fragment can be used to efficiently express data mining and pattern matching
tasks over trajectory data.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:08:53 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Gomez",
"Leticia",
""
],
[
"Kuijpers",
"Bart",
""
],
[
"Vaisman",
"Alejandro",
""
]
] |
0708.2718 | Adela Kawka | Stephane Vennes, Adela Kawka, J. Allyn Smith | CPD-20 1123 (Albus 1) is a bright He-B Subdwarf | Accepted for publication in The Astrophysical Journal Letters | null | 10.1086/522605 | null | astro-ph | null | Based on photometric and astrometric data it has been proposed that Albus 1
(also known as CPD-20 1123) might be a hot white dwarf similar to G191-B2B or,
alternatively, a hot subdwarf. We obtained a series of optical spectra showing
that CPD-20 1123 is a bright He-B subdwarf. We analyzed the HI Balmer and HeI
line spectra and measured T_eff = 19800+/-400 K, log g = 4.55+/-0.10, and log
N(He)/N(H) = 0.15+/-0.15. This peculiar object belongs to a family of evolved
helium-rich stars that may be the products of double-degenerate mergers, or,
alternatively, the products of post horizontal- or giant-branch evolution.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:10:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vennes",
"Stephane",
""
],
[
"Kawka",
"Adela",
""
],
[
"Smith",
"J. Allyn",
""
]
] |
0708.2719 | Adam Kraus | Adam L. Kraus, Lynne A. Hillenbrand | The Stellar Populations of Praesepe and Coma Berenices | Accepted to AJ; 14 pages, 10 figures, 5 tables + 2 online-only tables | Astron.J.134:2340-2352,2007 | 10.1086/522831 | null | astro-ph | null | We present the results of a stellar membership survey of the nearby open
clusters Praesepe and Coma Berenices. We have combined archival survey data
from the SDSS, 2MASS, USNOB1.0, and UCAC-2.0 surveys to compile proper motions
and photometry for ~5 million sources over 300 deg^2. Of these sources, 1010
stars in Praesepe and 98 stars in Coma Ber are identified as candidate members
with probability >80%; 442 and 61 are identified as high-probability candidates
for the first time. We estimate that this survey is >90% complete across a wide
range of spectral types (F0 to M5 in Praesepe, F5 to M6 in Coma Ber). We have
also investigated the stellar mass dependence of each cluster's mass and radius
in order to quantify the role of mass segregation and tidal stripping in
shaping the present-day mass function and spatial distribution of stars.
Praesepe shows clear evidence of mass segregation across the full stellar mass
range; Coma Ber does not show any clear trend, but low number statistics would
mask a trend of the same magnitude as in Praesepe. The mass function for
Praesepe (t~600 Myr; M~500 Msun) follows a power law consistent with that of
the field present-day mass function, suggesting that any mass-dependent tidal
stripping could have removed only the lowest-mass members (<0.15 Msun). Coma
Ber, which is younger but much less massive (t~400 Myr; M~100 Msun), follows a
significantly shallower power law. This suggests that some tidal stripping has
occurred, but the low-mass stellar population has not been strongly depleted
down to the survey completeness limit (~0.12 Msun).
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:44:47 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kraus",
"Adam L.",
""
],
[
"Hillenbrand",
"Lynne A.",
""
]
] |
0708.2720 | Matthew Anderson | Matthew Anderson, Eric W. Hirschmann, Luis Lehner, Steven L. Liebling,
Patrick M. Motl, David Neilsen, Carlos Palenzuela, Joel E. Tohline | Simulating binary neutron stars: dynamics and gravitational waves | 14 pages, 16 figures. Added one figure from previous version;
corrected typos | Phys.Rev.D77:024006,2008 | 10.1103/PhysRevD.77.024006 | null | gr-qc astro-ph | null | We model two mergers of orbiting binary neutron stars, the first forming a
black hole and the second a differentially rotating neutron star. We extract
gravitational waveforms in the wave zone. Comparisons to a post-Newtonian
analysis allow us to compute the orbital kinematics, including trajectories and
orbital eccentricities. We verify our code by evolving single stars and
extracting radial perturbative modes, which compare very well to results from
perturbation theory. The Einstein equations are solved in a first order
reduction of the generalized harmonic formulation, and the fluid equations are
solved using a modified convex essentially non-oscillatory method. All
calculations are done in three spatial dimensions without symmetry assumptions.
We use the \had computational infrastructure for distributed adaptive mesh
refinement.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:11:01 GMT"
},
{
"version": "v2",
"created": "Fri, 4 Jan 2008 18:49:47 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Anderson",
"Matthew",
""
],
[
"Hirschmann",
"Eric W.",
""
],
[
"Lehner",
"Luis",
""
],
[
"Liebling",
"Steven L.",
""
],
[
"Motl",
"Patrick M.",
""
],
[
"Neilsen",
"David",
""
],
[
"Palenzuela",
"Carlos",
""
],
[
"Tohline",
"Joel E.",
""
]
] |
0708.2721 | Timo Seppalainen | Timo Seppalainen | Directed random growth models on the plane | 30 pages | Analysis and Stochastics of Growth Processes and Interface Models,
edited by P. Morters et al., p. 9-38, Oxford University Press, 2008. | null | null | math.PR | null | This is a brief survey of laws of large numbers, fluctuation results and
large deviation principles for asymmetric interacting particle systems that
represent moving interfaces on the plane. We discuss the exclusion process, the
Hammersley process and the related last-passage growth models.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:14:08 GMT"
}
] | 2009-11-24T00:00:00 | [
[
"Seppalainen",
"Timo",
""
]
] |
0708.2722 | P. S. Howe | E. Bergshoeff, P. S. Howe, S. Kerstan and L. Wulff | Kappa-symmetric SL(2,R) covariant D-brane actions | 20 pages. Minor clarification in text. References added | JHEP 0710:050,2007 | 10.1088/1126-6708/2007/10/050 | KCL-TH-07-12, UG-07-05 | hep-th | null | A superspace formulation of IIB supergravity which includes the field
strengths of the duals of the usual physical one, three and five-form field
strengths as well as the eleven-form field strength is given. The
superembedding formalism is used to construct kappa-symmetric SL(2,R) covariant
D-brane actions in an arbitrary supergravity background.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:18:17 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 07:52:00 GMT"
},
{
"version": "v3",
"created": "Thu, 30 Aug 2007 12:05:46 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Bergshoeff",
"E.",
""
],
[
"Howe",
"P. S.",
""
],
[
"Kerstan",
"S.",
""
],
[
"Wulff",
"L.",
""
]
] |
0708.2723 | Zhe-Yu Jeff Ou | Z. Y. Ou | Characterizing Temporal Distinguishability of an N-Photon State by
Generalized Photon Bunching Effect with Multi-Photon Interference | null | null | 10.1103/PhysRevA.77.043829 | null | quant-ph | null | The complementary principle of quantum mechanics relates qualitatively the
visibility of quantum interference with path indistinguishability. Here we
propose a scheme of constructive quantum interference involving superposition
between an $N$-photon state and a single-photon state to characterize
quantitatively the degree of temporal distinguishability of the $N$-photon
state. This scheme is based on a generalized photon bunching effect. Such a
scheme can be extended to other more general cases.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:30:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ou",
"Z. Y.",
""
]
] |
0708.2724 | Michael Zwolak | Michael Zwolak, Massimiliano Di Ventra | Physical approaches to DNA sequencing and detection | 26 pages, 22 figures | Rev. Mod. Phys. 80, 141 (2008) | 10.1103/RevModPhys.80.141 | LAUR-07-5650 | physics.bio-ph cond-mat.soft q-bio.BM | null | With the continued improvement of sequencing technologies, the prospect of
genome-based medicine is now at the forefront of scientific research. To
realize this potential, however, we need a revolutionary sequencing method for
the cost-effective and rapid interrogation of individual genomes. This
capability is likely to be provided by a physical approach to probing DNA at
the single nucleotide level. This is in sharp contrast to current techniques
and instruments which probe, through chemical elongation, electrophoresis, and
optical detection, length differences and terminating bases of strands of DNA.
In this Colloquium we review several physical approaches to DNA detection that
have the potential to deliver fast and low-cost sequencing. Center-fold to
these approaches is the concept of nanochannels or nanopores which allow for
the spatial confinement of DNA molecules. In addition to their possible impact
in medicine and biology, the methods offer ideal test beds to study open
scientific issues and challenges in the relatively unexplored area at the
interface between solids, liquids, and biomolecules at the nanometer length
scale. We emphasize the physics behind these methods and ideas, critically
describe their advantages and drawbacks, and discuss future research
opportunities in this field.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:32:13 GMT"
}
] | 2008-01-03T00:00:00 | [
[
"Zwolak",
"Michael",
""
],
[
"Di Ventra",
"Massimiliano",
""
]
] |
0708.2725 | Damien Calaque | Damien Calaque and Michel Van den Bergh | Hochschild cohomology and Atiyah classes | Reference to work of Cattaneo, Felder and Willwacher added | Advances in Mathematics 224 (2010), no. 5, 1839--1889 | 10.1016/j.aim.2010.01.012 | null | math.KT math.QA | null | In this paper we prove that on a smooth algebraic variety the HKR-morphism
twisted by the square root of the Todd genus gives an isomorphism between the
sheaf of poly-vector fields and the sheaf of poly-differential operators, both
considered as derived Gerstenhaber algebras. In particular we obtain an
isomorphism between Hochschild cohomology and the cohomology of poly-vector
fields which is compatible with the Lie bracket and the cupproduct. The latter
compatibility is an unpublished result by Kontsevich. Our proof is set in the
framework of Lie algebroids and so applies without modification in much more
general settings as well.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:40:15 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 22:41:55 GMT"
},
{
"version": "v3",
"created": "Fri, 12 Oct 2007 10:32:08 GMT"
},
{
"version": "v4",
"created": "Fri, 2 Nov 2007 16:49:46 GMT"
}
] | 2010-10-06T00:00:00 | [
[
"Calaque",
"Damien",
""
],
[
"Bergh",
"Michel Van den",
""
]
] |
0708.2726 | Richard V. E. Lovelace | G.S. Bisnovatyi-Kogan and R.V.E. Lovelace | Large Scale B-Field in Stationary Accretion Disks | 5 pages, 2 figures | null | 10.1086/522206 | null | astro-ph | null | We reconsider the problem of the formation of a large-scale magnetic field in
the accretion disks around black holes. In contrast with previous work we take
into account the nonuniform vertical structure of the disk. The high electrical
conductivity of the outer layers of the disk prevents the outward diffusion of
the magnetic field. This implies a stationary state with a strong magnetic
field in the inner parts of the accretion disk close to the black hole.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:36:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bisnovatyi-Kogan",
"G. S.",
""
],
[
"Lovelace",
"R. V. E.",
""
]
] |
0708.2727 | Lawrence Brown | Lawrence G. Brown and Gert K. Pedersen | Limits and C*-algebras of low rank or dimension | This is the second-to-last of our joint papers and will appear in the
Journal of Operator Theory | J. Oper. Theory 61:2 (2009), 381-417 | null | null | math.OA | null | We explore various limit constructions for C*-algebras, such as composition
series and inverse limits, in relation to the notions of real rank, stable
rank, and extremal richness. We also consider extensions and pullbacks. We
identify some conditions under which the constructions preserve low rank for
the C*-algebras or their multiplier algebras. We also discuss the version of
topological dimension theory appropriate for primitive ideal spaces of
C*-algebras and provide an analogue for rank of the countable sum theorem of
dimension theory. As an illustration of how the main results can be applied, we
show that a CCR algebra has stable rank one if and only if it has topological
dimension zero or one, and we characterize those sigma-unital CCR algebras
whose multiplier algebras have stable rank one or extremal richness. (The real
rank zero case was already known.)
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:39:54 GMT"
}
] | 2017-06-09T00:00:00 | [
[
"Brown",
"Lawrence G.",
""
],
[
"Pedersen",
"Gert K.",
""
]
] |
0708.2728 | Sanjit Mitra | Sanjit Mitra, Sanjeev Dhurandhar, Tarun Souradeep, Albert Lazzarini,
Vuk Mandic, Sukanta Bose and Stefan Ballmer | Gravitational wave radiometry: Mapping a stochastic gravitational wave
background | 24 pages, 19 figures, pdflatex. Matched version published in Phys.
Rev. D - minor changes | Phys.Rev.D77:042002,2008 | 10.1103/PhysRevD.77.042002 | IUCAA 28/07, LIGO-P070033-Z | gr-qc astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The problem of the detection and mapping of a stochastic gravitational wave
background (SGWB), either of cosmological or astrophysical origin, bears a
strong semblance to the analysis of CMB anisotropy and polarization. The basic
statistic we use is the cross-correlation between the data from a pair of
detectors. In order to `point' the pair of detectors at different locations one
must suitably delay the signal by the amount it takes for the gravitational
waves (GW) to travel to both detectors corresponding to a source direction.
Then the raw (observed) sky map of the SGWB is the signal convolved with a beam
response function that varies with location in the sky. We first present a
thorough analytic understanding of the structure of the beam response function
using an analytic approach employing the stationary phase approximation. The
true sky map is obtained by numerically deconvolving the beam function in the
integral (convolution) equation. We adopt the maximum likelihood framework to
estimate the true sky map that has been successfully used in the broadly
similar, well-studied CMB map making problem. We numerically implement and
demonstrate the method on simulated (unpolarized) SGWB for the radiometer
consisting of the LIGO pair of detectors at Hanford and Livingston. We include
`realistic' additive Gaussian noise in each data stream based on the LIGO-I
noise power spectral density. The extension of the method to multiple baselines
and polarized GWB is outlined. In the near future the network of GW detectors,
including the Advanced LIGO and Virgo detectors that will be sensitive to
sources within a thousand times larger spatial volume, could provide promising
data sets for GW radiometry.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:43:30 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jun 2008 07:04:04 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Mitra",
"Sanjit",
""
],
[
"Dhurandhar",
"Sanjeev",
""
],
[
"Souradeep",
"Tarun",
""
],
[
"Lazzarini",
"Albert",
""
],
[
"Mandic",
"Vuk",
""
],
[
"Bose",
"Sukanta",
""
],
[
"Ballmer",
"Stefan",
""
]
] |
0708.2729 | Donald W. Hoard | D. W. Hoard (1), Steve B. Howell (2), Carolyn S. Brinkworth (1), David
R. Ciardi (3), Stefanie Wachter (1) ((1) Spitzer Science Center, California
Institute of Technology, (2) WIYN Observatory and National Optical Astronomy
Observatory, (3) Michelson Science Center, California Institute of
Technology) | The Mid-Infrared Spectrum of the Short Orbital Period Polar EF Eridani
from the Spitzer Space Telescope | To be published in The Astrophysical Journal | null | 10.1086/522694 | null | astro-ph | null | We present the first mid-infrared (5.5-14.5 micron) spectrum of a highly
magnetic cataclysmic variable, EF Eridani, obtained with the Infrared
Spectrograph on the Spitzer Space Telescope. The spectrum displays a relatively
flat, featureless continuum. A spectral energy distribution model consisting of
a 9500 K white dwarf, L5 secondary star, cyclotron emission corresponding to a
B~13 MG white dwarf magnetic field, and an optically thin circumbinary dust
disk is in reasonable agreement with the extant 2MASS, IRAC, and IRS
observations of EF Eri. Cyclotron emission is ruled out as a dominant
contributor to the infrared flux density at wavelengths >3 microns. The
spectral energy distribution longward of ~5 microns is dominated by dust
emission. Even longer wavelength observations would test the model's prediction
of a continuing gradual decline in the circumbinary disk-dominated region of
the spectral energy distribution.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:46:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hoard",
"D. W.",
""
],
[
"Howell",
"Steve B.",
""
],
[
"Brinkworth",
"Carolyn S.",
""
],
[
"Ciardi",
"David R.",
""
],
[
"Wachter",
"Stefanie",
""
]
] |
0708.2730 | Heather Partner | Bradley A. Chase, Heather L. Partner, Brigette D. Black, Benjamin Q.
Baragiola, Robert L. Cook and JM Geremia | Magnetic Field Estimation at and beyond 1/N Scaling via an Effective
Nonlinearity | Please visit http://qmc.phys.unm.edu/ to download additional
resources, including all source code and data files used to produce this
manuscript | null | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We provide evidence, based on direct simulation of the quantum Fisher
information, that 1/N scaling of the sensitivity with the number of atoms N in
an atomic magnetometer can be surpassed by double-passing a far-detuned laser
through the atomic system during Larmor precession. Furthermore, we predict
that for N>>1, the proposed double-pass atomic magnetometer can essentially
achieve 1/N scaling without requiring any appreciable amount of entanglement.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:46:42 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Apr 2009 16:40:12 GMT"
}
] | 2009-04-14T00:00:00 | [
[
"Chase",
"Bradley A.",
""
],
[
"Partner",
"Heather L.",
""
],
[
"Black",
"Brigette D.",
""
],
[
"Baragiola",
"Benjamin Q.",
""
],
[
"Cook",
"Robert L.",
""
],
[
"Geremia",
"JM",
""
]
] |
0708.2731 | Heiko Lacker | H. Lacker | CKM matrix fits including constraints on New Physics | 11 pages, 15 figures, Talk given at Flavor Physics & CP Violation
Conference, Bled, 2007 | ECONFC070512:018,2007 | null | fpcp07_212 | hep-ph | null | I review the status of global fits to the CKM matrix within the framework of
the Standard Model and also allowing for New Physics contributions in B-Bbar
mixing. The driving force is coming from the large data sets collected by the
B-factory experiments BABAR and Belle. Additional important inputs to the B_s
sector are provided by the Tevatron experiments CDF and D0. In particular, when
constraining New Physics in B-Bbar mixing in a model-independent analysis a
nice interplay between the B-factories and the Tevatron experiments is
observed.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:51:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lacker",
"H.",
""
]
] |
0708.2732 | Yingbin Liang | Yingbin Liang and H. Vincent Poor | Secrecy Capacity Region of Binary and Gaussian Multiple Access Channels | In Proceedings of the 44th Annual Allerton Conference on
Communication, Control and Computing, University of Illinois, Monticello, IL,
September 27-29, 2006 | null | null | null | cs.IT math.IT | null | A generalized multiple access channel (GMAC) with one confidential message
set is studied, where two users (users 1 and 2) attempt to transmit common
information to a destination, and user 1 also has confidential information
intended for the destination. Moreover, user 1 wishes to keep its confidential
information as secret as possible from user 2. A deterministic GMAC is first
studied, and the capacity-equivocation region and the secrecy capacity region
are obtained. Two main classes of the GMAC are then studied: the binary GMAC
and the Gaussian GMAC. For both channels, the capacity-equivocation region and
the secrecy capacity region are established.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 20:53:10 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Liang",
"Yingbin",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0708.2733 | Yingbin Liang | Yingbin Liang and H. Vincent Poor | Secure Communications over Fading Channels | In Proceedings of the 44th Annual Allerton Conference on
Communication, Control and Computing, University of Illinois, Monticello, IL,
September 27 - 29, 2006 | null | null | null | cs.IT math.IT | null | The fading wire-tap channel is investigated, where the source-to-destination
channel and the source-to-wire-tapper channel are corrupted by multiplicative
fading gain coefficients in addition to additive Gaussian noise terms. The
channel state information is assumed to be known at both the transmitter and
the receiver. The parallel wire-tap channel with independent subchannels is
first studied, which serves as an information-theoretic model for the fading
wire-tap channel. The secrecy capacity of the parallel wire-tap channel is
established. This result is then specialized to give the secrecy capacity of
the fading wire-tap channel, which is achieved with the source node dynamically
changing the power allocation according to the channel state realization. An
optimal source power allocation is obtained to achieve the secrecy capacity.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 21:16:32 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Liang",
"Yingbin",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0708.2734 | Doerte Blume | D. Blume, J. von Stecher and Chris H. Greene | Universal properties of a trapped two-component Fermi gas at unitarity | 4 pages, 2 Figs., 2 Tables (minor changes) | Phys. Rev. Lett. 99, 233201 (2007) | 10.1103/PhysRevLett.99.233201 | null | cond-mat.other | null | We treat the trapped two-component Fermi system, in which unlike fermions
interact through a two-body short-range potential having no bound state but an
infinite scattering length. By accurately solving the Schroedinger equation for
up to N=6 fermions, we show that no many-body bound states exist other than
those bound by the trapping potential, and we demonstrate unique universal
properties of the system: Certain excitation frequencies are separated by
$2\hbar\omega$, the wavefunctions agree with analytical predictions and a
virial theorem is fulfilled. Further calculations up to N=30 determine the
excitation gap, an experimentally accessible universal quantity, and it agrees
with recent predictions based on a density functional approach.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 16:42:54 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Dec 2007 22:45:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Blume",
"D.",
""
],
[
"von Stecher",
"J.",
""
],
[
"Greene",
"Chris H.",
""
]
] |
0708.2735 | Stephen D. H. Hsu | N.G. Deshpande, Stephen D.H. Hsu, Jing Jiang | Long range forces and limits on unparticle interactions | 7 pages, revtex; v2 minor changes and added references | Phys.Lett.B659:888-890,2008 | 10.1016/j.physletb.2007.12.018 | null | hep-ph | null | Couplings between standard model particles and unparticles from a nontrivial
scale invariant sector can lead to long range forces. If the forces couple to
quantities such as baryon or lepton (electron) number, stringent limits result
from tests of the gravitational inverse square law. These limits are much
stronger than from collider phenomenology and astrophysics.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 00:10:45 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 22:54:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Deshpande",
"N. G.",
""
],
[
"Hsu",
"Stephen D. H.",
""
],
[
"Jiang",
"Jing",
""
]
] |
0708.2736 | Andrew Norris | Andrew N. Norris | Eulerian conjugate stress and strain | 17 pages | J. Mech. Materials Struct. 3(2), 243-260, 2008 | null | null | cond-mat.mtrl-sci | null | New results are presented for the stress conjugate to arbitrary Eulerian
strain measures. The conjugate stress depends on two arbitrary quantities: the
strain measure f(V) and the corotational rate defined by the spin \Omega. It is
shown that for every choice of f there is a unique spin, called the f-spin,
which makes the conjugate stress as close as possible to the Cauchy stress. The
f-spin reduces to the logarithmic spin when the strain measure is the Hencky
strain log(V). The formulation and the results emphasize the similarities in
form of the Eulerian and Lagrangian stresses conjugate to the strains f(V) and
f(U), respectively. Many of the results involve the solution to the equation
AX-XA=Y, which is presented in a succinct format.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 21:39:04 GMT"
},
{
"version": "v2",
"created": "Tue, 23 Oct 2007 01:08:22 GMT"
}
] | 2008-05-13T00:00:00 | [
[
"Norris",
"Andrew N.",
""
]
] |
0708.2737 | Miguel Urbaneja | Miguel A. Urbaneja, Rolf Peter Kudritzki and Fabio Bresolin
(University of Hawaii Institute for Astronomy) | Extragalaxtic Stellar Astronomy | 4 pages, 1 figure, to appear in the conference proceedings "Galaxies
in the Local Volume", eds. B.S. Koribalski and H. Jerjen | null | null | null | astro-ph | null | Despite their paucity, massive hot stars are real cosmic engines of
fundamental importance in shaping our Universe, from its very early stages up
to its current appearance. Understanding the physics of massive stars is then a
key issue for many relevant astrophysical phenomena. Probing the massive
stellar population of nearby galaxies by means of quantitative spectroscopy
allows us to unveil a wealth of information that will aid our current
understanding of stellar and galaxy evolution. In addition, blue luminous stars
can be used as standard candles for extragalactic distances up to 10 Mpc. In
this contribution, we present a brief overview of recent steps we have
undertaken in this exciting research field.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 21:45:20 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Urbaneja",
"Miguel A.",
"",
"University of Hawaii Institute for Astronomy"
],
[
"Kudritzki",
"Rolf Peter",
"",
"University of Hawaii Institute for Astronomy"
],
[
"Bresolin",
"Fabio",
"",
"University of Hawaii Institute for Astronomy"
]
] |
0708.2738 | Amitabh Virmani | Aaron J. Amsel, Donald Marolf, Amitabh Virmani | The Physical Process First Law for Bifurcate Killing Horizons | 19 pages; v2: ref added, minor changes | Phys.Rev.D77:024011,2008 | 10.1103/PhysRevD.77.024011 | null | gr-qc hep-th | null | The physical process version of the first law for black holes states that the
passage of energy and angular momentum through the horizon results in a change
in area $\frac{\kappa}{8 \pi} \Delta A = \Delta E - \Omega \Delta J$, so long
as this passage is quasi-stationary. A similar physical process first law can
be derived for any bifurcate Killing horizon in any spacetime dimension $d \ge
3$ using much the same argument. However, to make this law non-trivial, one
must show that sufficiently quasi-stationary processes do in fact occur. In
particular, one must show that processes exist for which the shear and
expansion remain small, and in which no new generators are added to the
horizon. Thorne, MacDonald, and Price considered related issues when an object
falls across a d=4 black hole horizon. By generalizing their argument to
arbitrary $d \ge 3$ and to any bifurcate Killing horizon, we derive a condition
under which these effects are controlled and the first law applies. In
particular, by providing a non-trivial first law for Rindler horizons, our work
completes the parallel between the mechanics of such horizons and those of
black holes for $d \ge 3$. We also comment on the situation for d=2.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 21:50:07 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2007 21:00:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Amsel",
"Aaron J.",
""
],
[
"Marolf",
"Donald",
""
],
[
"Virmani",
"Amitabh",
""
]
] |
0708.2739 | Lasse Leskel\"a | Lasse Leskel\"a | Stabilization of an overloaded queueing network using measurement-based
admission control | Published at http://dx.doi.org/10.1239/jap/1143936256 in the Journal
of Applied Probability (http://projecteuclid.org/jap) by the Applied
Probability Trust (http://www.appliedprobability.org/) | Journal of Applied Probability 2006 Vol. 43, No. 1, 231-244 | 10.1239/jap/1143936256 | null | math.PR | null | Admission control can be employed to avoid congestion in queueing networks
subject to overload. In distributed networks the admission decisions are often
based on imperfect measurements on the network state. This paper studies how
the lack of complete state information affects the system performance by
considering a simple network model for distributed admission control. The
stability region of the network is characterized and it is shown how feedback
signaling makes the system very sensitive to its parameters.
| [
{
"version": "v1",
"created": "Mon, 20 Aug 2007 21:51:47 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Leskelä",
"Lasse",
""
]
] |
0708.2740 | Paul Ruffle | P. M. E. Ruffle (1), T. J. Millar (1), H. Roberts (1), D. A. Lubowich
(2), C. Henkel (3), J. M. Pasachoff (4) and G. Brammer (4). ((1) The
University of Manchester, UK, (2) Hofstra University, NY, USA, (3) MPIfR,
Bonn, Germany, (4) Williams College, MA, USA) | Galactic Edge Clouds I: Molecular Line Observations and Chemical
Modelling of Edge Cloud 2 | Accepted by ApJ 7 August 2007. 29 pages, 9 figures, 10 tables. PMR
now at NRAO, Green Bank, WV, USA. TJM now at Queen's University Belfast, UK.
GB now at Yale University, CT, USA | null | 10.1086/522775 | null | astro-ph | null | Edge Cloud 2 (EC2) is a molecular cloud, about 35 pc in size, with one of the
largest galactocentric distances known to exist in the Milky Way. We present
observations of a peak CO emission region in the cloud and use these to
determine its physical characteristics. We calculate a gas temperature of 20 K
and a density of n(H2) ~ 10^4 cm^-3. Based on our CO maps, we estimate the mass
of EC2 at around 10^4 M_sun and continuum observations suggest a dust-to-gas
mass ratio as low as 0.001. Chemical models have been developed to reproduce
the abundances in EC2 and they indicate that: heavy element abundances may be
reduced by a factor of five relative to the solar neighbourhood (similar to
dwarf irregular galaxies and damped Lyman alpha systems); very low extinction
(Av < 4 mag) due to a very low dust-to-gas ratio; an enhanced cosmic ray
ionisation rate; and a higher UV field compared to local interstellar values.
The reduced abundances may be attributed to the low level of star formation in
this region and are probably also related to the continuing infall of
primordial (or low metallicity) halo gas since the Milky Way formed. Finally,
we note that shocks from the old supernova remnant GSH 138-01-94 may have
determined the morphology and dynamics of EC2.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 17:12:16 GMT"
},
{
"version": "v2",
"created": "Tue, 28 Aug 2007 16:17:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ruffle",
"P. M. E.",
""
],
[
"Millar",
"T. J.",
""
],
[
"Roberts",
"H.",
""
],
[
"Lubowich",
"D. A.",
""
],
[
"Henkel",
"C.",
""
],
[
"Pasachoff",
"J. M.",
""
],
[
"Brammer",
"G.",
""
],
[
".",
"",
""
]
] |
0708.2741 | Stephen Fegan | V. V. Vassiliev and S. J. Fegan | Schwarzschild-Couder two-mirror telescope for ground-based gamma-ray
astronomy | 4 pages, 6 figures, in Proc. 30th International Cosmic Ray
Conference, Merida, Mexico, 2007 | null | null | null | astro-ph | null | Schwarzschild-type aplanatic telescopes with two aspheric mirrors, configured
to correct spherical and coma aberrations, are considered for application in
gamma-ray astronomy utilizing the ground-based atmospheric Cherenkov technique.
We use analytical descriptions for the figures of primary and secondary mirrors
and, by means of numerical ray-tracing, we find telescope configurations which
minimize astigmatism and maximize effective light collecting area. It is shown
that unlike the traditional prime-focus Davies-Cotton design, such telescopes
provide a solution for wide field of view gamma-ray observations. The designs
are isochronous, can be optimized to have no vignetting across the field, and
allow for significant reduction of the plate scale, making them compatible with
finely-pixilated cameras, which can be constructed from modern, cost-effective
image sensors such as multi-anode PMTs, SiPMs, or image intensifiers.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 00:05:21 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Vassiliev",
"V. V.",
""
],
[
"Fegan",
"S. J.",
""
]
] |
0708.2742 | Igor Moskalenko | Igor V. Moskalenko (Stanford), Troy A. Porter (UCSC) | The Gamma-ray Albedo of the Moon | 6 pages, 4 figures, emulateapj.cls; to appear in the Astrophysical
Journal | Astrophys.J.670:1467-1472,2007 | 10.1086/522828 | null | astro-ph | null | We use the GEANT4 Monte Carlo framework to calculate the gamma-ray albedo of
the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our
calculation of the albedo spectrum agrees with the EGRET data. We show that the
spectrum of gamma rays from the Moon is very steep with an effective cutoff
around 3-4 GeV (600 MeV for the inner part of the Moon disk) and exhibits a
narrow pion-decay line at 67.5 MeV, perhaps unique in astrophysics. Apart from
other astrophysical sources, the albedo spectrum of the Moon is well
understood, including its absolute normalisation; this makes it a useful
"standard candle" for gamma-ray telescopes. The steep albedo spectrum also
provides a unique opportunity for energy calibration of gamma-ray telescopes,
such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). Since the
albedo flux depends on the incident CR spectrum which changes over the solar
cycle, it is possible to monitor the CR spectrum using the albedo gamma-ray
flux. Simultaneous measurements of CR proton and helium spectra by the Payload
for Antimatter-Matter Exploration and Light-nuclei Astrophysics (PAMELA), and
observations of the albedo gamma rays by the GLAST Large Area Telescope (LAT),
can be used to test the model predictions and will enable the LAT to monitor
the CR spectrum near the Earth beyond the lifetime of the PAMELA.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 00:55:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Moskalenko",
"Igor V.",
"",
"Stanford"
],
[
"Porter",
"Troy A.",
"",
"UCSC"
]
] |
0708.2743 | Andreas Albrecht | Andreas Albrecht and Alberto Iglesias | The clock ambiguity and the emergence of physical laws | 16 Pages including two appendices and 5 figures. V2: Some additional
references added for completeness. No other changes. (Final version accepted
for publication in PRD.) | Phys.Rev.D77:063506,2008 | 10.1103/PhysRevD.77.063506 | null | hep-th gr-qc | null | The process of identifying a time variable in time reparameterization
invariant theories results in great ambiguities about the actual laws of
physics described by a given theory. A theory set up to describe one set of
physical laws can equally well be interpreted as describing any other laws of
physics by making a different choice of time variable or ``clock''. In this
article we demonstrate how this ``clock ambiguity'' arises and then discuss how
one might still hope to extract specific predictions about the laws of physics
even when the clock ambiguity is present. We argue that a requirement of
quasi-separability should play a critical role in such an analysis. As a step
in this direction, we compare the Hamiltonian of a local quantum field theory
with a completely random Hamiltonian. We find that any random Hamiltonian
(constructed in a sufficiently large space) can yield a ``good enough''
approximation to a local field theory. Based on this result we argue that
theories that suffer from the clock ambiguity may in the end provide a viable
fundamental framework for physics in which locality can be seen as a strongly
favored (or predicted) emergent behavior. We also speculate on how other key
aspects of known physics such as gauge symmetries and Poincare invariance might
be predicted to emerge in this framework.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 00:30:53 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jan 2008 19:47:18 GMT"
}
] | 2010-04-08T00:00:00 | [
[
"Albrecht",
"Andreas",
""
],
[
"Iglesias",
"Alberto",
""
]
] |
0708.2744 | Bahram Mashhoon | C. Chicone and B. Mashhoon | Nonlocal Lagrangians for Accelerated Systems | 11 pages, no figures; v2: 20 pages; expanded version accepted for
publication in Ann. Phys. (Leipzig); v3: several typos corrected to match the
published version | Annalen Phys.16:811-823,2007 | 10.1002/andp.200710266 | null | hep-th gr-qc | null | Acceleration-induced nonlocality and the corresponding Lorentz-invariant
nonlocal field equations of accelerated systems in Minkowski spacetime are
discussed. Under physically reasonable conditions, the nonlocal equation of
motion of the field can be derived from a variational principle of stationary
action involving a nonlocal Lagrangian that is simply obtained by composing the
local inertial Lagrangian with the nonlocal transformation of the field to the
accelerated system. The implications of this approach for the electromagnetic
and Dirac fields are briefly discussed.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 01:51:29 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Oct 2007 21:57:18 GMT"
},
{
"version": "v3",
"created": "Thu, 15 Nov 2007 22:42:28 GMT"
}
] | 2012-05-22T00:00:00 | [
[
"Chicone",
"C.",
""
],
[
"Mashhoon",
"B.",
""
]
] |
0708.2745 | Alex Kim | Alex G. Kim, Ramon Miquel | Measuring Type Ia Supernova Distances and Redshifts From Their
Multi-band Light Curves | 16 pages, 4 figures, Astroparticle Physics, accepted | Astropart.Phys.28:448-455,2007 | 10.1016/j.astropartphys.2007.08.009 | null | astro-ph | null | The distance and redshift of a type Ia supernova can be determined
simultaneously through its multi-band light curves. This fact may be used for
imaging surveys that discover and obtain photometry for large numbers of
supernovae; so many that it would be difficult to obtain a spectroscopic
redshift for each. Using available supernova-analysis tools we find that there
are several conditions in which a viable distance-redshift can be determined.
Uncertainties in the effective distance at z~0.3 are dominated by redshift
uncertainties coupled with the steepness of the Hubble law. By z~0.5 the Hubble
law flattens out and distance-modulus uncertainties dominate. Observations that
give S/N=50 at peak brightness and a four-day observer cadence in each of
griz-bands are necessary to match the intrinsic supernova magnitude dispersion
out to z=1.0. Lower S/N can be tolerated with the addition of redshift priors
(e.g. from a host-galaxy photometric redshift), observations in an additional
redder band, or by focusing on supernova redshifts that have particular
leverage for this measurement. More stringent S/N requirements are anticipated
as improved systematics control over intrinsic color, metallicity, and dust is
attempted to be drawn from light curves.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 00:36:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kim",
"Alex G.",
""
],
[
"Miquel",
"Ramon",
""
]
] |
0708.2746 | Sara Haravifard | S. Haravifard, K.C. Rule, H.A. Dabkowska, B.D. Gaulin, Z. Yamani and
W.J.L. Buyers | Neutron and X-ray Scattering Studies of the Lightly-Doped Spin-Peierls
System Cu(1-x)Cd(x)GeO3 | 15 Pages, 7 Figures, Submitted to J. Phys. :Condensed Matter | null | 10.1088/0953-8984/19/43/436222 | null | cond-mat.str-el | null | Single crystals of the lightly-doped spin-Peierls system Cu(1-x)Cd(x)GeO3
have been studied using bulk susceptibility, x-ray diffraction, and inelastic
neutron scattering techniques. We investigate the triplet gap in the magnetic
excitation spectrum of this quasi-one dimensional quantum antiferromagnet, and
its relation to the spin-Peierls dimerisation order parameter. We employ two
different theoretical forms to model the inelastic neutron scattering cross
section and chi''(Q,omega), and show the sensitivity of the gap energy to the
choice of chi''(Q,omega). We find that a finite gap exists at the spin-Peierls
phase transition.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 00:52:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Haravifard",
"S.",
""
],
[
"Rule",
"K. C.",
""
],
[
"Dabkowska",
"H. A.",
""
],
[
"Gaulin",
"B. D.",
""
],
[
"Yamani",
"Z.",
""
],
[
"Buyers",
"W. J. L.",
""
]
] |
0708.2747 | Abhishek Agarwal | Abhishek Agarwal | Aspects of Integrability in N =4 SYM | Invited brief review for Mod. Phys. Lett. A based on a talk at I.A.S,
Princeton | Mod.Phys.Lett.A22:2549-2563,2007 | 10.1142/S021773230702542X | null | hep-th | null | Various recently developed connections between supersymmetric Yang-Mills
theories in four dimensions and two dimensional integrable systems serve as
crucial ingredients in improving our understanding of the AdS/CFT
correspondence. In this review, we highlight some connections between
superconformal four dimensional Yang-Mills theory and various integrable
systems. In particular, we focus on the role of Yangian symmetries in studying
the gauge theory dual of closed string excitations. We also briefly review how
the gauge theory connects to Calogero models and open quantum spin chains
through the study of the gauge theory duals of D3 branes and open strings
ending on them. This invited review, written for Modern Physics Letters-A, is
based on a seminar given at the Institute of Advanced Study, Princeton.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 01:00:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Agarwal",
"Abhishek",
""
]
] |
0708.2748 | Jim Freericks | O. P. Matveev (Inst. Condens. Mat. Phys. Lviv, Ukraine), A. M. Shvaika
(Inst. Condens. Mat. Phys. Lviv, Ukraine), and J. K. Freericks (Georgetown
University) | Optical and dc transport properties of a strongly correlated charge
density wave system: exact solution in the ordered phase of the spinless
Falicov-Kimball model with dynamical mean-field theory | 14 pages, 14 figures, submitted to Phys. Rev. B | Phys. Rev. B 77, 035102-1--13 (2008) | 10.1103/PhysRevB.77.035102 | null | cond-mat.str-el | null | We derive the dynamical mean-field theory equations for transport in an
ordered charge-density-wave phase on a bipartite lattice. The formalism is
applied to the spinless Falicov-Kimball model on a hypercubic lattice at half
filling. We determine the many-body density of states, the dc charge and heat
conductivities, and the optical conductivity. Vertex corrections continue to
vanish within the ordered phase, but the density of states and the transport
coefficients show anomalous behavior due to the rapid development of thermally
activated subgap states. We also examine the optical sum rule and sum rules for
the first three moments of the Green's functions within the ordered phase and
see that the total optical spectral weight in the ordered phase either
decreases or increases depending on the strength of the interactions.
| [
{
"version": "v1",
"created": "Tue, 21 Aug 2007 01:37:08 GMT"
}
] | 2008-08-14T00:00:00 | [
[
"Matveev",
"O. P.",
"",
"Inst. Condens. Mat. Phys. Lviv, Ukraine"
],
[
"Shvaika",
"A. M.",
"",
"Inst. Condens. Mat. Phys. Lviv, Ukraine"
],
[
"Freericks",
"J. K.",
"",
"Georgetown\n University"
]
] |
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