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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.3930 | \c{S}ebnem G. S\"oyler | \c{S}. G. S\"oyler, B. Capogrosso-Sansone, N. V. Prokof'ev, B. V.
Svistunov | Superfluid-Insulator and Roughening Transitions in Domain Walls | 6 pages, 7 figures; references added, typo corrected in fig 5 | Physical Review A, vol. 76, 043628 (2007) | 10.1103/PhysRevA.76.043628 | null | cond-mat.other cond-mat.stat-mech | null | We have performed quantum Monte Carlo simulations to investigate the
superfluid behavior of one- and two-dimensional interfaces separating
checkerboard solid domains. The system is described by the hard-core
Bose-Hubbard Hamiltonian with nearest-neighbor interaction. In accordance with
Ref.1, we find that (i) the interface remains superfluid in a wide range of
interaction strength before it undergoes a superfluid-insulator transition;
(ii) in one dimension, the transition is of the Kosterlitz-Thouless type and is
accompanied by the roughening transition, driven by proliferation of charge 1/2
quasiparticles; (iii) in two dimensions, the transition belongs to the 3D U(1)
universality class and the interface remains smooth. Similar phenomena are
expected for domain walls in quantum antiferromagnets.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:28:03 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Nov 2007 05:28:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Söyler",
"Ş. G.",
""
],
[
"Capogrosso-Sansone",
"B.",
""
],
[
"Prokof'ev",
"N. V.",
""
],
[
"Svistunov",
"B. V.",
""
]
] |
0707.3931 | Oleg Vyaselev | A. V. Palnichenko, O. M. Vyaselev, N. S. Sidorov | Influence of Rb, Cs and Ba on Superconductivity of Magnesium Diboride | 3 pages (twocolumn), 2 figures | null | 10.1134/S0021364007160126 | null | cond-mat.supr-con | null | Magnesium diboride has been thermally treated in the presence of Rb, Cs, and
Ba. Magnetic susceptibility shows onsets of superconductivity in the resulting
samples at 52K (Rb), 58K (Cs) and 45K (Ba). Room-temperature 11B NMR indicates
to cubic symmetry of the electric field gradient at boron site for the samples
reacted with Rb and Cs, in contrast to the axial symmetry in the initial MgB2
and in the sample treated with Ba.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:28:10 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 16:46:59 GMT"
},
{
"version": "v3",
"created": "Sat, 28 Jul 2007 08:02:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Palnichenko",
"A. V.",
""
],
[
"Vyaselev",
"O. M.",
""
],
[
"Sidorov",
"N. S.",
""
]
] |
0707.3932 | Andreas Wagner | A. Wagner, R. Beyer, M. Erhard, E. Grosse, A. R. Junghans, J. Klug, K.
Kosev, C. Nair, N. Nankov, G. Rusev, K. D. Schilling, R. Schwengner | Photon strength distributions in stable even-even molybdenum isotopes | Proceedings Nuclear Physics in Astrophysics 3, March 2007, Dresden
Journal of Physics G, IOP Publishing | J.Phys.G35:014035,2008 | 10.1088/0954-3899/35/1/014035 | null | nucl-ex | null | Electromagnetic dipole-strength distributions up to the particle separation
energies are studied for the stable even-even nuclides $^{92,94,96,98,100}$Mo
in photon scattering experiments at the superconducting electron accelerator
ELBE of the Forschungszentrum Dresden-Rossendorf. The influence of inelastic
transitions to low-lying excited states has been corrected by a simulation of
$\gamma$ cascades using a statistical model. After corrections for branching
ratios of ground-state transitions, the photon-scattering cross-sections
smoothly connect to data obtained from $(\gamma,n)$-reactions. With the newly
determined electromagnetic dipole response of nuclei well below the particle
separation energies the parametrisation of the isovector giant-dipole resonance
is done with improved precision.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:28:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wagner",
"A.",
""
],
[
"Beyer",
"R.",
""
],
[
"Erhard",
"M.",
""
],
[
"Grosse",
"E.",
""
],
[
"Junghans",
"A. R.",
""
],
[
"Klug",
"J.",
""
],
[
"Kosev",
"K.",
""
],
[
"Nair",
"C.",
""
],
[
"Nankov",
"N.",
""
],
[
"Rusev",
"G.",
""
],
[
"Schilling",
"K. D.",
""
],
[
"Schwengner",
"R.",
""
]
] |
0707.3933 | Stefano Miscetti | The KLOE Collaboration | Branching ratio measurement of $K_S\to \gamma \gamma$ decay using a pure
$\ks$ beam in the KLOE detector | 15 pages, 9 figures, contributed paper to LP07 | null | null | null | hep-ex | null | We have analyzed 1.62 fb$^{-1}$ of $e^{+}e^{-}$ collisions at a center of
mass energy $\sim M_{\phi}$ collected by the KLOE experiment at DA$\Phi$NE.
This sample corresponds to a production of $\sim$ 1.7 billion of $\ks$ $\kl$
pairs which allowed us to search for the rare $K_S\to \gamma\gamma$ decay.
$K_S$ are tagged by the $K_L$ interaction in the calorimeter and the signal is
searched for by requiring two additional prompt photons. Strong kinematic
requirements reduce the initial 0.5$\times 10^6$ events to 2300 candidates from
which we extract a signal of 600 $\pm$ 35 events. By normalizing to the $\ks
\to 2 \pi^0$ decays counted in the same sample, the measured value of BR($\ks
\to \gamma\gamma$) is (2.27 $\pm 0.13(stat.) ^{+0.03}_{-0.04} (syst.)) \times
10^{-6}$, in agreement with $O(P^4)$ Chiral Perturbation Theory predictions.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:28:22 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"The KLOE Collaboration",
"",
""
]
] |
0707.3934 | Simone Daflon | S. Daflon, K. Cunha, F. X. de Araujo, S. Wolff, N. Przybilla | The Projected Rotational Velocity Distribution of a Sample of OB stars
from a Calibration based on Synthetic He I lines | Accepted for publication in The Astronomical Journal | Astron.J.134:1570-1578,2007 | 10.1086/521707 | null | astro-ph | null | We derive projected rotational velocities (vsini) for a sample of 156
Galactic OB star members of 35 clusters, HII regions, and associations. The HeI
lines at $\lambda\lambda$4026, 4388, and 4471A were analyzed in order to define
a calibration of the synthetic HeI full-widths at half maximum versus stellar
vsini. A grid of synthetic spectra of HeI line profiles was calculated in
non-LTE using an extensive helium model atom and updated atomic data. The
vsini's for all stars were derived using the He I FWHM calibrations but also,
for those target stars with relatively sharp lines, vsini values were obtained
from best fit synthetic spectra of up to 40 lines of CII, NII, OII, AlIII,
MgII, SiIII, and SIII. This calibration is a useful and efficient tool for
estimating the projected rotational velocities of O9-B5 main-sequence stars.
The distribution of vsini for an unbiased sample of early B stars in the
unbound association Cep OB2 is consistent with the distribution reported
elsewhere for other unbound associations.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:29:36 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Daflon",
"S.",
""
],
[
"Cunha",
"K.",
""
],
[
"de Araujo",
"F. X.",
""
],
[
"Wolff",
"S.",
""
],
[
"Przybilla",
"N.",
""
]
] |
0707.3935 | Gennady Kovalev V. | Gennady V. Kovalev | A Possibility of Volume Refraction of Negative Relativistic Particles in
Bent Crystals | 6 pages, 2 figures, draft | null | null | null | physics.acc-ph physics.atom-ph physics.gen-ph | null | The volume coherent deflection of high-energy positive and negative particles
in uniformly bent crystals is studied. The general analysis of potential
scattering shows that the standard screening potential for a large class of
collisions can cause the volume refraction for negative particles (antiprotons,
electrons) instead of the volume reflection for positive particles (proton,
positrons).
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:47:27 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 20:46:45 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Kovalev",
"Gennady V.",
""
]
] |
0707.3936 | Konstantin Avrachenkov | Eitan Altman (INRIA Sophia Antipolis), Konstantin Avrachenkov (INRIA
Sophia Antipolis), Andrey Garnaev | Closed form solutions for symmetric water filling games | null | null | null | null | cs.NI cs.GT | null | We study power control in optimization and game frameworks. In the
optimization framework there is a single decision maker who assigns network
resources and in the game framework users share the network resources according
to Nash equilibrium. The solution of these problems is based on so-called
water-filling technique, which in turn uses bisection method for solution of
non-linear equations for Lagrange multiplies. Here we provide a closed form
solution to the water-filling problem, which allows us to solve it in a finite
number of operations. Also, we produce a closed form solution for the Nash
equilibrium in symmetric Gaussian interference game with an arbitrary number of
users. Even though the game is symmetric, there is an intrinsic hierarchical
structure induced by the quantity of the resources available to the users. We
use this hierarchical structure to perform a successive reduction of the game.
In addition, to its mathematical beauty, the explicit solution allows one to
study limiting cases when the crosstalk coefficient is either small or large.
We provide an alternative simple proof of the convergence of the Iterative
Water Filling Algorithm. Furthermore, it turns out that the convergence of
Iterative Water Filling Algorithm slows down when the crosstalk coefficient is
large. Using the closed form solution, we can avoid this problem. Finally, we
compare the non-cooperative approach with the cooperative approach and show
that the non-cooperative approach results in a more fair resource distribution.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:30:50 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 12:40:05 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Altman",
"Eitan",
"",
"INRIA Sophia Antipolis"
],
[
"Avrachenkov",
"Konstantin",
"",
"INRIA\n Sophia Antipolis"
],
[
"Garnaev",
"Andrey",
""
]
] |
0707.3937 | Andrey Lazarev | Alastair Hamilton and Andrey Lazarev | Cohomology theories for homotopy algebras and noncommutative geometry | This 54 pages paper is a substantial revision of the part of
math.QA/0410621 dealing with algebraic Hodge decompositions of Hochschild and
cyclic cohomology theories. The main addition is the treatment of cohomology
theories corresponding to unital infinity-structures | Algebr. Geom. Topol. 9 (2009) 1503-1583 | 10.2140/agt.2009.9.1503 | null | math.QA math.AG math.KT | null | This paper builds a general framework in which to study cohomology theories
of strongly homotopy algebras, namely $A_\infty, C_\infty$ and
$L_\infty$-algebras. This framework is based on noncommutative geometry as
expounded by Connes and Kontsevich. The developed machinery is then used to
establish a general form of Hodge decomposition of Hochschild and cyclic
cohomology of $C_\infty$-algebras. This generalizes and puts in a conceptual
framework previous work by Loday and Gerstenhaber-Schack.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:38:53 GMT"
}
] | 2014-10-01T00:00:00 | [
[
"Hamilton",
"Alastair",
""
],
[
"Lazarev",
"Andrey",
""
]
] |
0707.3938 | Roland Doll | Roland Doll, David Zueco, Martijn Wubs, Sigmund Kohler and Peter
Hanggi | On the conundrum of deriving exact solutions from approximate master
equations | 7 pages; revised version; to appear in Chem. Phys | Chem. Phys. 347, 243-249 (2008) | 10.1016/j.chemphys.2007.09.003 | null | quant-ph cond-mat.stat-mech | null | We derive the exact time-evolution for a general quantum system under the
influence of pure phase-noise and demonstrate that for a Gaussian initial state
of the bath, the exact result can be obtained also within a perturbative
time-local master equation approach already in second order of the system-bath
coupling strength. We reveal that this equivalence holds if the initial state
of the bath can be mapped to a Gaussian phase-space distribution function.
Moreover, we discuss the relation to the standard Bloch-Redfield approach.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:59:42 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 14:51:53 GMT"
}
] | 2008-05-13T00:00:00 | [
[
"Doll",
"Roland",
""
],
[
"Zueco",
"David",
""
],
[
"Wubs",
"Martijn",
""
],
[
"Kohler",
"Sigmund",
""
],
[
"Hanggi",
"Peter",
""
]
] |
0707.3939 | Karen O'Neil | K. O'Neil | Star Formation in Massive Low Surface Brightness Galaxies | to be published in proceeding of IAU 244 - Dark Galaxies and Lost
Baryons IAU Symposium | AIP Conf.Proc.1035:112-118,2008 | 10.1063/1.2973561 | null | astro-ph | null | Massive low surface brightness galaxies have disk central surface
brightnesses at least one magnitude fainter than the night sky, but total
magnitudes and masses that show they are among the largest galaxies known. Like
all low surface brightness (LSB) galaxies, massive LSB galaxies are often in
the midst of star formation yet their stellar light has remained diffuse,
raising the question of how star formation is proceeding within these galaxies.
We have undertaken a multi-wavelength study to clarify the structural
parameters and stellar and gas content of these enigmatic systems. The results
of these studies, which include HI, CO, optical, near UV, and far UV images of
the galaxies will provide the most in depth study done to date of how, when,
and where star formation proceeds within this unique subset of the galaxy
population.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 14:55:59 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"O'Neil",
"K.",
""
]
] |
0707.3940 | Andrea Carati | A. Carati, L. Galgani | A proposal for the missing mass: it is just the outer, far one | This paper has been withdrawn | null | null | null | astro-ph | null | The paper has benn withdrawn because the computation of the external virial
contains an error which invalidate the main result.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:10:24 GMT"
},
{
"version": "v2",
"created": "Tue, 28 Aug 2007 12:37:41 GMT"
}
] | 2007-08-28T00:00:00 | [
[
"Carati",
"A.",
""
],
[
"Galgani",
"L.",
""
]
] |
0707.3941 | Mark Edelman | G.M Zaslavsky, M. Edelman, V.E. Tarasov | Dynamics of the Chain of Oscillators with Long-Range Interaction: From
Synchronization to Chaos | 22 pages, 10 figures | null | 10.1063/1.2819537 | null | nlin.CD nlin.PS | null | We consider a chain of nonlinear oscillators with long-range interaction of
the type 1/l^{1+alpha}, where l is a distance between oscillators and 0< alpha
<2. In the continues limit the system's dynamics is described by the
Ginzburg-Landau equation with complex coefficients. Such a system has a new
parameter alpha that is responsible for the complexity of the medium and that
strongly influences possible regimes of the dynamics. We study different
spatial-temporal patterns of the dynamics depending on alpha and show
transitions from synchronization of the motion to broad-spectrum oscillations
and to chaos.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 18:38:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zaslavsky",
"G. M",
""
],
[
"Edelman",
"M.",
""
],
[
"Tarasov",
"V. E.",
""
]
] |
0707.3942 | Barbara Betz | Barbara Betz, Philip Rau, Horst St\"ocker | Mach Cones and Hydrodynamic Flow: Probing Big Bang Matter in the
Laboratory | 18 pages, 12 figures, presented at the IWCF 2006, Nov. 21-24,
Hangzhou, China | Int.J.Mod.Phys.E16:3082-3099,2008 | 10.1142/S0218301307009075 | null | hep-th | null | A critical discussion of the present signals for the phase transition to
quark-gluon plasma (QGP) is given. Since hadronic rescattering models predict
much larger flow than observed from 1 to 50 A GeV laboratory bombarding
energies, this observation is interpreted as potential evidence for a
first-order phase transition at high baryon density. A detailed discussion of
the collective flow as a barometer for the equation of state (EoS) of hot dense
matter at RHIC follows. Here, hadronic rescattering models can explain < 30 %
of the observed elliptic flow v_2 for $p_T > 2$ GeV/c. This is interpreted as
an evidence for the production of superdense matter at RHIC. The connection of
v_2 to jet suppression is examined. A study of Mach shocks generated by fast
partonic jets propagating through the QGP is given. The main goal is to take
into account different types of collective motion during the formation and
evolution of this matter. A significant deformation of Mach shocks in central
Au+Au collisions at RHIC and LHC energies as compared to the case of jet
propagation in a static medium is predicted. A new hydrodynamical study of jet
energy loss is presented.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:04:30 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 14:48:04 GMT"
},
{
"version": "v3",
"created": "Mon, 13 Aug 2007 09:55:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Betz",
"Barbara",
""
],
[
"Rau",
"Philip",
""
],
[
"Stöcker",
"Horst",
""
]
] |
0707.3943 | J\'er\^ome Ballot | J\'er\^ome Ballot, Allan Sacha Brun, Sylvaine Turck-Chi\`eze | Simulations of turbulent convection in rotating young solar-like stars:
Differential rotation and meridional circulation | 32 pages, 18 figures, 2 tables, to appear in ApJ | ApJ 669, 1190 (Nov 10, 2007) | 10.1086/521617 | null | astro-ph | null | We present the results of three-dimensional simulations of the deep
convective envelope of a young (10 Myr) one-solar-mass star, obtained with the
Anelastic Spherical Harmonic code. Since young stars are known to be faster
rotators than their main sequence counterparts, we have systematically studied
the impact of the stellar rotation speed, by considering stars spinning up to
five times as fast as the Sun. The aim of these nonlinear models is to
understand the complex interactions between convection and rotation. We discuss
the influence of the turbulence level and of the rotation rate on the intensity
and the topology of the mean flows. For all of the computed models, we find a
solar-type superficial differential rotation, with an equatorial acceleration,
and meridional circulation that exhibits a multicellular structure. Even if the
differential rotation contrast decreases only marginally for high rotation
rates, the meridional circulation intensity clearly weakens according to our
simulations. We have also shown that, for Taylor numbers above a certain
threshold (Ta>10^9), the convection can develop a vacillating behavior. Since
simulations with high turbulence levels and rotation rates exhibit strongly
cylindrical internal rotation profiles, we have considered the influence of
baroclinic effects at the base of the convective envelope of these young Suns,
to see whether such effect can modify the otherwise near cylindrical profiles
to produce more conical, solar-like profiles.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:06:32 GMT"
}
] | 2008-04-03T00:00:00 | [
[
"Ballot",
"Jérôme",
""
],
[
"Brun",
"Allan Sacha",
""
],
[
"Turck-Chièze",
"Sylvaine",
""
]
] |
0707.3944 | Anastasios Avgoustidis | A. Avgoustidis, Joaquim Gomis | Non-Relativistic Strings in Expanding Spacetime | 35 pages, 3 figures. Minor corrections, accepted by CQG | Class.Quant.Grav.25:125017,2008 | 10.1088/0264-9381/25/12/125017 | UB-ECM-PF-07-19 | astro-ph gr-qc hep-th | null | We obtain a non-relativistic diffeomorphism invariant string action as a
special limit of the Nambu-Goto action in an FLRW background. We use this
action to study non-relativistic string dynamics in an expanding universe and
construct an analytic model describing the macroscopic properties of
non-relativistic string networks. The non-relativistic constraint equations
allow arbitrarily small string velocities and thus a `frustrated' equation of
state for non-interacting strings can be obtained without the need of a
velocity damping mechanism. Assuming that colliding string segments reconnect
by exchange of partners, non-relativistic string networks exhibit scaling
behaviour, but with enhanced energy densities due to the reduced average string
velocity. Non-relativistic string networks can be relevant in several contexts
in condensed matter physics and cosmology.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:23:17 GMT"
},
{
"version": "v2",
"created": "Wed, 30 Apr 2008 09:28:45 GMT"
}
] | 2009-06-19T00:00:00 | [
[
"Avgoustidis",
"A.",
""
],
[
"Gomis",
"Joaquim",
""
]
] |
0707.3945 | Markus J\"org | Markus J\"org | k-Disjunctive cuts and a finite cutting plane algorithm for general
mixed integer linear programs | 18 pages, 2 figures | null | null | null | math.OC | null | In this paper we give a generalization of the well known split cuts of Cook,
Kannan and Schrijver to cuts which are based on multi-term disjunctions. They
will be called k-disjunctive cuts. The starting point is the question what kind
of cuts is needed for a finite cutting plane algorithm for general mixed
integer programs. We will deal with this question in detail and derive cutting
planes based on k-disjunctions related to a given cut vector. Finally we will
show how a finite cutting plane algorithm can be established using these cuts
in combination with Gomory mixed integer cuts.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:15:18 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Jörg",
"Markus",
""
]
] |
0707.3946 | Dimitris G. Angelakis | Dimitris G. Angelakis and Alastair Kay | Implementing universal quantum gates in coupled cavities | Accepted to appear in the AIP proceedings of the "Quantum Control and
Light-Matter Interactions: Recent Computational and Theoretical Results"
Symposium of ICCMSE 2007 | Am. Inst. of Phys. Vol. 963, 763 (2007) | 10.1063/1.2836195 | null | quant-ph | null | We study a linear array of coupled cavities interacting with two level
systems and show how to construct individually addressable qubits in this
system from the long-lived atom-photon excitations (polaritons) at each site.
We derive the system dynamics and show that is described by an XY Hamiltonian.
We proceed by showing how to implement non-local quantum gates and show that
combined with the inherent ability for individual addressing, universal quantum
computation is possible in this system. We finally discuss the prospects for
experimental implementation using various technologies involving dopants as
atoms, quantum dots or Cooper pair boxes.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:16:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Angelakis",
"Dimitris G.",
""
],
[
"Kay",
"Alastair",
""
]
] |
0707.3947 | Ekaterina Amerik | Ekaterina Amerik | A computation of invariants of a rational self-map | LaTeX, 10 pages | null | null | null | math.AG | null | I compute the dynamical degrees in C. Voisin's example of a rational self-map
of the variety of lines on a cubic fourfold.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:19:08 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Amerik",
"Ekaterina",
""
]
] |
0707.3948 | Ekaterina Amerik | Ekaterina Amerik, Claire Voisin | Potential density of rational points on the variety of lines of a cubic
fourfold | LaTeX, 22 pages | null | null | null | math.AG | null | We prove the potential density of rational points on the variety of lines of
a sufficiently general cubic fourfold defined over a number field, where
``sufficiently general'' means that a condition of Terasoma type is satisfied.
These varieties have trivial canonical bundle and have geometric Picard group
equal to $\mathbb{Z}$.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:27:55 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Amerik",
"Ekaterina",
""
],
[
"Voisin",
"Claire",
""
]
] |
0707.3949 | Dmitri Prokhorenko | D. V. Prokhorenko | Nonequilibrium Renormalization Theory I | null | null | null | null | cond-mat.stat-mech math-ph math.MP | null | In the present article we consider some general class of divergent diagrams
in Keldysh diagram technique. These divergences arise for nonequilibrium matter
and closely related to the divergences in the kinetic theory of gases. We
suggest a scheme of renormalization of such divergences and illustrate it on
some examples. In the other papers of these series we develop the general
theory of renormalization of nonequilibrium diagram technique. The fact that
thermal divergences in non-equilibrium diagram technique can be renormalized
leads to the following consequence: to prove that the system tends to the
thermal equilibrium one should to take into account the behaviour of the system
on its boundary. In this paper we illustrate this fact on Bogoliubov derivation
of kinetic equations.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:27:57 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Sep 2007 15:49:06 GMT"
},
{
"version": "v3",
"created": "Thu, 4 Oct 2007 15:09:17 GMT"
}
] | 2007-10-04T00:00:00 | [
[
"Prokhorenko",
"D. V.",
""
]
] |
0707.3950 | Mark Villarino B. | Mark B. Villarino | Ramanujan's Harmonic Number Expansion into Negative Powers of a
Triangular Number | sharp error estimates and general formulas for Ramanujan's harmonic
number expansion; correction of typo in the Ramanujan-Lodge lower bound
constant; thanks to Jonathan Post and Martin Fuller; fixed typo in the title | null | null | null | math.CA math.GM | null | An algebraic transformation of the DeTemple-Wang half-integer approximation
to the harmonic series produces the general formula and error estimate for the
Ramanujan expansion for the nth harmonic number into negative powers of the nth
triangular number. We also discuss the history of the Ramanujan expansion for
the nth harmonic number as well as sharp estimates of its accuracy, with
complete proofs, and we compare it with other approximative formulas.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:28:24 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jul 2007 17:31:44 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Villarino",
"Mark B.",
""
]
] |
0707.3951 | Andrey Lazarev | Alastair Hamilton and Andrey Lazarev | Symplectic $C_\infty$-algebras | This paper is a substantial revision of the part of math.QA/0410621
dealing with sympectic $C_\infty$-algebras. The main addition is the
treatment of unital $C_\infty$-structures. 27 pages | null | null | null | math.QA math.AG math.KT | null | In this paper we show that a strongly homotopy commutative (or $C_\infty$-)
algebra with an invariant inner product on its cohomology can be uniquely
extended to a symplectic $C_\infty$-algebra (an $\infty$-generalisation of a
commutative Frobenius algebra introduced by Kontsevich). This result relies on
the algebraic Hodge decomposition of the cyclic Hochschild cohomology of a
$\ci$-algebra and does not generalize to algebras over other operads.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:42:28 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 21:37:23 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Hamilton",
"Alastair",
""
],
[
"Lazarev",
"Andrey",
""
]
] |
0707.3952 | Chong Sheng Li | Chong Sheng Li, Zhao Li, Robert J. Oakes, Li Lin Yang | Threshold Resummation Effects in the Associated Production of Chargino
and Neutralino at Hadron Colliders | revised version with midifications, several references added | Phys.Rev.D77:034010,2008 | 10.1103/PhysRevD.77.034010 | null | hep-ph | null | We investigate the QCD effects in the associated production of the chargino
and the neutralino, $\tilde\chi^\pm_{1}$ and $\tilde\chi^0_{2}$, in the Minimal
Supersymmetric Standard Model (MSSM) at both the Fermilab Tevatron and the CERN
Large Hadron Collider (LHC). We include the next-to-leading order (NLO) QCD
corrections (including supersymmetric QCD) and the threshold resummation
effects. Our results show that, compared to the NLO predictions, the threshold
resummation effects can increase the total cross sections by 3.6% and 3.9% for
the associated production of $\tilde\chi^+_{1}\tilde\chi^0_{2}$ and
$\tilde\chi^-_{1}\tilde\chi^0_{2}$ at the LHC, respectively, and by 4.7% for
those of $\tilde\chi^\pm_{1}\tilde\chi^0_{2}$ at the Tevatron. In the invariant
mass distributions the resummation effects are significant for large invariant
mass. The threshold resummation reduces the dependence of the total cross
sections at the LHC (Tevatron) on the renormalization/factorization scales to
5% (4%) from up to 7% (11%) at NLO.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:49:43 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 02:29:16 GMT"
},
{
"version": "v3",
"created": "Tue, 7 Aug 2007 07:39:58 GMT"
},
{
"version": "v4",
"created": "Mon, 19 Nov 2007 11:54:46 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Li",
"Chong Sheng",
""
],
[
"Li",
"Zhao",
""
],
[
"Oakes",
"Robert J.",
""
],
[
"Yang",
"Li Lin",
""
]
] |
0707.3953 | Michael Temkin | Michael Temkin | Stable modification of relative curves | 60 pages, third version, the paper was revised due to referee's
report, section 2 was divided into sections 2 and 6, to appear in JAG | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We generalize theorems of Deligne-Mumford and de Jong on semi-stable
modifications of families of proper curves. The main result states that after a
generically \'etale alteration of the base any (not necessarily proper) family
of multipointed curves with semi-stable generic fiber admits a minimal
semi-stable modification. The latter can also be characterized by the property
that its geometric fibers have no certain exceptional components. The main step
of our proof is uniformization of one-dimensional extensions of valued fields.
Riemann-Zariski spaces are then used to obtain the result over any integral
base.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:41:01 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Apr 2009 18:29:50 GMT"
},
{
"version": "v3",
"created": "Wed, 14 Apr 2010 21:40:22 GMT"
}
] | 2010-04-16T00:00:00 | [
[
"Temkin",
"Michael",
""
]
] |
0707.3954 | Diego Guadagnoli | Michaela E. Albrecht, Wolfgang Altmannshofer, Andrzej J. Buras, Diego
Guadagnoli, David M. Straub | Challenging SO(10) SUSY GUTs with family symmetries through FCNC
processes | 1 + 37 pages, 5 figures, 11 tables. v3: minor typos fixed. Matches
JHEP published version | JHEP0710:055,2007 | 10.1088/1126-6708/2007/10/055 | TUM-HEP-671/07 | hep-ph | null | We perform a detailed analysis of the SO(10) SUSY GUT model with D3 family
symmetry of Dermisek and Raby (DR). The model is specified in terms of 24
parameters and predicts, as a function of them, the whole MSSM set of
parameters at low energy scales. Concerning the SM subset of such parameters,
the model is able to give a satisfactory description of the quark and lepton
masses, of the PMNS matrix and of the CKM matrix. We perform a global fit to
the model, including flavour changing neutral current (FCNC) processes Bs -->
mu+ mu-, B --> Xs gamma, B --> Xs l+ l- and the B(d,s) - bar B(d,s) mass
differences Delta M(d,s) as well as the flavour changing (FC) process B+ -->
tau+ nu. These observables provide at present the most sensitive probe of the
SUSY mass spectrum and couplings predicted by the model. Our analysis
demonstrates that the simultaneous description of the FC observables in
question represents a serious challenge for the DR model, unless the masses of
the scalars are moved to regions which are problematic from the point of view
of naturalness and probably beyond the reach of the LHC. We emphasize that this
problem could be a general feature of SUSY GUT models with third generation
Yukawa unification and weak-scale minimal flavour violation.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:41:40 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 16:34:59 GMT"
},
{
"version": "v3",
"created": "Sun, 25 Nov 2007 13:24:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Albrecht",
"Michaela E.",
""
],
[
"Altmannshofer",
"Wolfgang",
""
],
[
"Buras",
"Andrzej J.",
""
],
[
"Guadagnoli",
"Diego",
""
],
[
"Straub",
"David M.",
""
]
] |
0707.3955 | Ricardo Pinto | R. A. Pinto and S. Flach | Quantum breathers in capacitively coupled Josephson junctions:
Correlations, number conservation, and entanglement | 10 pages, 9 figures. Improved version with further discussions.
Accepted in Physical Review B | null | 10.1103/PhysRevB.77.024308 | null | cond-mat.mes-hall cond-mat.other | null | We consider the classical and quantum dynamics of excitations in a system of
two capacitively coupled Josephson junctions. In the classical case the
equations of motion admit discrete breather solutions, which are time periodic
and localized predominantly on one of the junctions. In the quantum case
breather states are found in the central part of the energy spectrum of the
confined nonescaping states of the system. We perform a systematic analysis of
their tunneling frequency, site correlations, fluctuations of the number of
quanta, and entanglement. Quantum breather states show strong site correlation
of quanta and are characterized by a strong excitation of quanta on one
junction which perform slow coherent tunneling motion from one junction to the
other. They suppress fluctuations of the total number of excited quanta.
Quantum breather states are the least entangled states among the group of
eigenstates in the same range of the energy spectrum. We describe how quantum
breather excitations could be experimentally observed by employing the already
developed techniques for quantum information processing using Josephson
junctions.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 15:53:07 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Nov 2007 10:06:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pinto",
"R. A.",
""
],
[
"Flach",
"S.",
""
]
] |
0707.3956 | Jacob Sturm | D. H. Phong and Jacob Sturm | On the regularity of geodesic rays associated to test configurations | null | null | null | null | math.DG math.CV | null | Geodesic rays of class C^{1,1} are constructed for any test configuration of
a positive line bundle L on X using resolution of singularities. The
construction reduces to finding a subsolution of the corresponding Monge-Ampere
equation. Geometrically, this is accomplished by the use a positive line bundle
on the resolution which is trivial outside of the exceptional divisor.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 18:30:11 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Phong",
"D. H.",
""
],
[
"Sturm",
"Jacob",
""
]
] |
0707.3957 | Alexander V. Milovanov Dr. | Alexander V. Milovanov (1) Jens Juul Rasmussen (2) Kristoffer Rypdal
(1) ((1) Department of Physics and Technology, University of Tromso UiT,
Tromso, Norway; (2) Optics and Plasma Research Department, Riso National
Laboratory, Technical University of Denmark, Roskilde, Denmark) | Stretched-exponential decay functions from a self-consistent model of
dielectric relaxation | 17 pages | null | 10.1016/j.physleta.2007.11.025 | null | cond-mat.mtrl-sci cond-mat.stat-mech | null | There are many materials whose dielectric properties are described by a
stretched exponential, the so-called Kohlrausch-Williams-Watts (KWW) relaxation
function. Its physical origin and statistical-mechanical foundation have been a
matter of debate in the literature. In this paper we suggest a model of
dielectric relaxation, which naturally leads to a stretched exponential decay
function. Some essential characteristics of the underlying charge conduction
mechanisms are considered. A kinetic description of the relaxation and charge
transport processes is proposed in terms of equations with time-fractional
derivatives.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:05:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Milovanov",
"Alexander V.",
""
],
[
"Rasmussen",
"Jens Juul",
""
],
[
"Rypdal",
"Kristoffer",
""
]
] |
0707.3958 | Sandra Chapman | S. C. Chapman, G. Rowlands, N. W. Watkins | Control parameters in turbulence, Self Organized Criticality and
ecosystems | 1 manuscript file (Revtex), 2 figure files (.eps). Revised and
resubmitted to J. Phys. A | null | null | null | physics.bio-ph physics.gen-ph | null | From the starting point of the well known Reynolds number of fluid turbulence
we propose a control parameter $R$ for a wider class of systems including
avalanche models that show Self Organized Criticality (SOC) and ecosystems. $R$
is related to the driving and dissipation rates and from similarity analysis we
obtain a relationship $R\sim N^{\beta_N}$ where $N$ is the number of degrees of
freedom. The value of the exponent $\beta_N$ is determined by detailed
phenomenology but its sign follows from our similarity analysis. For SOC,
$R=h/\epsilon$ and we show that $\beta_N<0$ hence we show independent of the
details that the transition to SOC is when $R \to 0$, in contrast to fluid
turbulence, formalizing the relationship between turbulence (since $\beta_N
>0$, $R \to \infty$) and SOC ($R=h/\epsilon\to 0$). A corollary is that SOC
phenomenology, that is, power law scaling of avalanches, can persist for finite
$R$ with unchanged exponent if the system supports a sufficiently large range
of lengthscales; necessary for SOC to be a candidate for physical systems. We
propose a conceptual model ecosystem where $R$ is an observable parameter which
depends on the rate of throughput of biomass or energy; we show this has
$\beta_N>0$, so that increasing $R$ increases the abundance of species,
pointing to a critical value for species 'explosion'.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:46:05 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Feb 2008 09:57:16 GMT"
}
] | 2008-02-21T00:00:00 | [
[
"Chapman",
"S. C.",
""
],
[
"Rowlands",
"G.",
""
],
[
"Watkins",
"N. W.",
""
]
] |
0707.3959 | Dung Dao | Dung Ngoc Dao, Chau Yuen, Chintha Tellambura, Yong Liang Guan and
Tjeng Thiang Tjhung | Four-Group Decodable Space-Time Block Codes | 1 figure. Accepted for publication in IEEE Trans. on Signal
Processing | null | 10.1109/TSP.2007.906729 | null | cs.IT math.IT | null | Two new rate-one full-diversity space-time block codes (STBC) are proposed.
They are characterized by the \emph{lowest decoding complexity} among the known
rate-one STBC, arising due to the complete separability of the transmitted
symbols into four groups for maximum likelihood detection. The first and the
second codes are delay-optimal if the number of transmit antennas is a power of
2 and even, respectively. The exact pair-wise error probability is derived to
allow for the performance optimization of the two codes. Compared with existing
low-decoding complexity STBC, the two new codes offer several advantages such
as higher code rate, lower encoding/decoding delay and complexity, lower
peak-to-average power ratio, and better performance.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:14:33 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Dao",
"Dung Ngoc",
""
],
[
"Yuen",
"Chau",
""
],
[
"Tellambura",
"Chintha",
""
],
[
"Guan",
"Yong Liang",
""
],
[
"Tjhung",
"Tjeng Thiang",
""
]
] |
0707.3960 | Jozsef Garai | Jozsef Garai | P-V-T equation of state of epsilon iron and its densities at core
conditions | null | null | null | null | physics.gen-ph | null | The author's new p-V-T Equation of State is tested against the available
experiments of epsilon iron. The root-mean-square-deviations (RMSD) of the
molar volume, pressure, and temperature are 0.021 cm3, 2.0 GPa and 144.9 K
respectively. Separating the experiments into 200 K ranges the new EoS was
compared to the most widely used finite strain, interatomic potential, and
empirical isothermal EoSs such as the Burch-Murnaghan, the Vinet, and the
Roy-Roy respectively. Correlation coefficients, RMSDs of the residuals and
Akaike Information Criteria were used for evaluating the fittings. Based on
these fitting parameters the new p-V-T EoS is equal or better than the
conventional isothermal EoSs. The newly defined parameters were used to
calculate the density of the inner core. The calculated densities are
significantly lower than the current consensus indicating that it might be too
early excluding the possibility of a pure iron-nickel core with no light
elements.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:24:18 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Garai",
"Jozsef",
""
]
] |
0707.3961 | Douglas Galvao | Vitor R. Coluci, Nicola M. Pugno, Socrates O. Dantas, Douglas S.
Galvao and Ado Jorio | Atomistic Simulations of the Mechanical Properties of 'Super' Carbon
Nanotubes | 16 pages, 6 figures, to appear in Nanotechnology | null | 10.1088/0957-4484/18/33/335702 | null | cond-mat.mtrl-sci | null | The mechanical properties of the so-called `super' carbon nanotubes (STs) are
investigated using classical molecular dynamics simulations. The STs are built
from single walled carbon nanotubes (SWCNTs) connected by Y-like junctions
forming an ordered carbon nanotube network that is then rolled into a seamless
cylinder. We observed that the ST behavior under tensile tests is similar to
the one presented by fishing nets. This interesting behavior provides a way to
vary the accessible channels to the inner parts of STs by applying external
mechanical load. The Young's modulus is dependent on the ST chirality and it
inversely varies with the ST radius. Smaller reduction of breaking strain
values due to temperature increase is predicted for zigzag STs compared to
SWCNTs. The results show that, for STs with radius ~ 5 nm, the junctions
between the constituent SWCNTs play an important role on the fracture process.
The Young's modulus and tensile strength were estimated for hierarchical
higher-order STs using scaling laws related to the ST fractal dimension. The
obtained mechanical properties suggest that STs may be used in the development
of new porous, flexible, and high-strength materials.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:31:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Coluci",
"Vitor R.",
""
],
[
"Pugno",
"Nicola M.",
""
],
[
"Dantas",
"Socrates O.",
""
],
[
"Galvao",
"Douglas S.",
""
],
[
"Jorio",
"Ado",
""
]
] |
0707.3962 | Nelson Christensen | Christian R\"over, Renate Meyer, Gianluca M. Guidi, Andrea Vicer\'e,
Nelson Christensen | Coherent Bayesian analysis of inspiral signals | Accepted for publication in Classical and Quantum Gravity, Special
issue for GWDAW-11 | Class.Quant.Grav.24:S607-S616,2007 | 10.1088/0264-9381/24/19/S23 | null | gr-qc | null | We present in this paper a Bayesian parameter estimation method for the
analysis of interferometric gravitational wave observations of an inspiral of
binary compact objects using data recorded simultaneously by a network of
several interferometers at different sites. We consider neutron star or black
hole inspirals that are modeled to 3.5 post-Newtonian (PN) order in phase and
2.5 PN in amplitude. Inference is facilitated using Markov chain Monte Carlo
methods that are adapted in order to efficiently explore the particular
parameter space. Examples are shown to illustrate how and what information
about the different parameters can be derived from the data. This study uses
simulated signals and data with noise characteristics that are assumed to be
defined by the LIGO and Virgo detectors operating at their design
sensitivities. Nine parameters are estimated, including those associated with
the binary system, plus its location on the sky. We explain how this technique
will be part of a detection pipeline for binary systems of compact objects with
masses up to $20 \sunmass$, including cases where the ratio of the individual
masses can be extreme.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:33:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Röver",
"Christian",
""
],
[
"Meyer",
"Renate",
""
],
[
"Guidi",
"Gianluca M.",
""
],
[
"Viceré",
"Andrea",
""
],
[
"Christensen",
"Nelson",
""
]
] |
0707.3963 | Meinrenken | E. Meinrenken | On the quantization of conjugacy classes | 32 pages | Enseign. Math. (2) 55 (2009), no. 1-2, 33-75 | null | null | math.DG | null | Let G be a compact, simple, simply connected Lie group. A theorem of
Freed-Hopkins-Teleman identifies the level k fusion ring R_k(G) of G with the
twisted equivariant K-homology at level k+h, where h is the dual Coxeter
number. In this paper, we review this result using the language of
Dixmier-Douady bundles. We show that the additive generators of the group
R_k(G) are obtained as K-homology push-forwards of the fundamental classes of
conjugacy classes in G.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:58:35 GMT"
}
] | 2011-10-10T00:00:00 | [
[
"Meinrenken",
"E.",
""
]
] |
0707.3964 | Antonio M. Garcia-Garcia | Antonio M. Garcia-Garcia and Jiao Wang | Universality in quantum chaos and the one parameter scaling theory | 4 pages, 2 figures, acknowledgment added, typos corrected | Phys. Rev. Lett. 100, 070603 (2008) | 10.1103/PhysRevLett.100.070603 | null | cond-mat.dis-nn cond-mat.mes-hall nlin.CD quant-ph | null | We adapt the one parameter scaling theory (OPT) to the context of quantum
chaos. As a result we propose a more precise characterization of the
universality classes associated to Wigner-Dyson and Poisson statistics which
takes into account Anderson localization effects. Based also on the OPT we
predict a new universality class in quantum chaos related to the
metal-insulator transition and provide several examples. In low dimensions it
is characterized by classical superdiffusion or a fractal spectrum, in higher
dimensions it can also have a purely quantum origin as in the case of
disordered systems. Our findings open the possibility of studying the metal
insulator transition experimentally in a much broader type of systems.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:40:48 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 16:56:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Garcia-Garcia",
"Antonio M.",
""
],
[
"Wang",
"Jiao",
""
]
] |
0707.3965 | Walter Christensen Jr. | Walter J. Christensen Jr | Haar Wavelets and the Origin of Gravitational Inertia | null | null | null | null | physics.gen-ph | null | Spacetime is considered to be everywhere Minkowski except at the location
where a signal wave of energy interacts with the gravitational field. The
conformal metric f[k(x-vt)]Nuv is suitably chosen to represent this
interaction, where f[k(x-vt)]is a generalized wave or signal function.
Parametrized and Taylor expanded at zero, the spacetime metric is transformed
into a Haar wavelet having parameter width tau. Applying the Haar metric to the
time component of General Relativistic wave equation reduces it from a second
ordered covariant differential equation to a first ordered partial differential
equation that allows the Einstein Tensor to be easily be expressed in the
familiar Poisson form for gravitation. By comparison with the matter density of
this equation, to the Haar-Einstein result, shows that the wavelength of a
graviton becomes the fundamental source for gravitational attraction. Since the
signal wave is unidirectional, it strongly supports Machs assumption that
inertia arises from all the matter in the universe. Furthermore, because the
Haar metric is conformal, the signal metric is solved for exactly.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:42:50 GMT"
},
{
"version": "v2",
"created": "Sun, 29 Jul 2007 00:17:54 GMT"
}
] | 2010-07-28T00:00:00 | [
[
"Christensen",
"Walter J.",
"Jr"
]
] |
0707.3966 | Dirk H. Rischke | Masakiyo Kitazawa, Dirk H. Rischke, Igor A. Shovkovy | Bose-Einstein condensation of diquark molecules in three-flavor quark
matter | 8 pages, 3 figures, proceedings of YKIS 2006 "New Frontiers in QCD" | Prog.Theor.Phys.Suppl.168:389-396,2007 | 10.1143/PTPS.168.389 | null | nucl-th | null | We study the phase diagram of strongly interacting matter with three quark
flavors at low and intermediate densities and non-zero temperatures in the
framework of an NJL-type model with four-point interactions. At large
densities, when the interactions are weak due to asymptotic freedom, quarks
form loosely bound Cooper pairs. However, when the density decreases,
interactions become stronger and quark Cooper pairs transform smoothly into
tightly bound diquark molecules. We find that such molecules are stable at low
density and temperature and that they dissociate above a temperature $T_{\rm
diss}$ of the order of the chiral phase transition temperature $T_c \sim 170$
MeV. We also explore the conditions under which these molecules undergo
Bose-Einstein condensation (BEC). We find that BEC is only possible if we
increase the attractive interaction in the diquark channel to (probably
unrealistically) large values.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:45:38 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kitazawa",
"Masakiyo",
""
],
[
"Rischke",
"Dirk H.",
""
],
[
"Shovkovy",
"Igor A.",
""
]
] |
0707.3967 | Juan Bueno-Sanchez | J. C. Bueno Sanchez and K. Dimopoulos | Curvaton reheating allows TeV Hubble scale in NO inflation | 4 pages, no figures | JCAP0711:007,2007 | 10.1088/1475-7516/2007/11/007 | null | hep-ph astro-ph hep-th | null | Curvaton reheating is studied in non-oscillatory (NO) models of inflation,
with the aim to obtain bounds on the parameters of curvaton models and find out
whether low scale inflation can be attained. Using a minimal curvaton model, it
is found that the allowed parameter space is considerably larger than in the
case of the usual oscillatory inflation models. In particular, inflation with
Hubble scale as low as 1 TeV is comfortably allowed.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:47:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sanchez",
"J. C. Bueno",
""
],
[
"Dimopoulos",
"K.",
""
]
] |
0707.3968 | Charles B. Leffert | Charles B. Leffert | Phenomenology for Supernova Ia Data Based on a New Cosmic Time | PDF, 36 pages, 18 figures, All rights reserved | null | null | null | physics.gen-ph | null | A new phenomenological theory for the expansion of our universe is presented.
Because fundamental supporting theory is still in development, its discussion
is not presented in this paper. The theory is based on a new algebraic
expression for cosmic time G Rho t^2=3/32Pi, which correctly predicts the WMAP
measured cosmological constants and the fundamental Hubble parameter H(t) for
the expansion of the universe. A replacement for dark matter, called here "dark
mass", is proposed which scales as with the expansion and incorporated. It does
not react with ordinary matter, except gravitationally, and produces flat
rotational curves for spiral galaxies. Also a new expression for the
approaching velocity of radiation in a closed 3-sphere expanding universe is
given that accounts for the early degrading negative approach of radiation for
z > 1.7. The expression is v = Hr-c. Combining these three elements produces a
luminosity distance dL that successfully predicts the apparent magnitude of
exploding supernova Ia stars and even the new gamma ray bursts with no need for
dark energy or acceleration of the expansion of the universe.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:50:35 GMT"
}
] | 2011-01-26T00:00:00 | [
[
"Leffert",
"Charles B.",
""
]
] |
0707.3969 | Nelson Christensen | Christian R\"over, Alexander Stroeer, Ed Bloomer, Nelson Christensen,
James Clark, Martin Hendry, Chris Messenger, Renate Meyer, Matt Pitkin,
Jennifer Toher, Richard Umst\"atter, Alberto Vecchio, John Veitch, Graham
Woan | Inference on inspiral signals using LISA MLDC data | Accepted for publication in Classical and Quantum Gravity, GWDAW-11
special issue | Class.Quant.Grav.24:S521-S528,2007 | 10.1088/0264-9381/24/19/S15 | null | gr-qc | null | In this paper we describe a Bayesian inference framework for analysis of data
obtained by LISA. We set up a model for binary inspiral signals as defined for
the Mock LISA Data Challenge 1.2 (MLDC), and implemented a Markov chain Monte
Carlo (MCMC) algorithm to facilitate exploration and integration of the
posterior distribution over the 9-dimensional parameter space. Here we present
intermediate results showing how, using this method, information about the 9
parameters can be extracted from the data.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:30:21 GMT"
},
{
"version": "v2",
"created": "Sun, 5 Aug 2007 14:17:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Röver",
"Christian",
""
],
[
"Stroeer",
"Alexander",
""
],
[
"Bloomer",
"Ed",
""
],
[
"Christensen",
"Nelson",
""
],
[
"Clark",
"James",
""
],
[
"Hendry",
"Martin",
""
],
[
"Messenger",
"Chris",
""
],
[
"Meyer",
"Renate",
""
],
[
"Pitkin",
"Matt",
""
],
[
"Toher",
"Jennifer",
""
],
[
"Umstätter",
"Richard",
""
],
[
"Vecchio",
"Alberto",
""
],
[
"Veitch",
"John",
""
],
[
"Woan",
"Graham",
""
]
] |
0707.3970 | Daowen Qiu | Daowen Qiu | Minimum-error discrimination between mixed quantum states | A further revised version, and some results have been added | Phys. Rev. A 77, 012328 (2008) | 10.1103/PhysRevA.77.012328 | null | quant-ph | null | We derive a general lower bound on the minimum-error probability for {\it
ambiguous discrimination} between arbitrary $m$ mixed quantum states with given
prior probabilities. When $m=2$, this bound is precisely the well-known
Helstrom limit. Also, we give a general lower bound on the minimum-error
probability for discriminating quantum operations. Then we further analyze how
this lower bound is attainable for ambiguous discrimination of mixed quantum
states by presenting necessary and sufficient conditions related to it.
Furthermore, with a restricted condition, we work out a upper bound on the
minimum-error probability for ambiguous discrimination of mixed quantum states.
Therefore, some sufficient conditions are obtained for the minimum-error
probability attaining this bound. Finally, under the condition of the
minimum-error probability attaining this bound, we compare the minimum-error
probability for {\it ambiguously} discriminating arbitrary $m$ mixed quantum
states with the optimal failure probability for {\it unambiguously}
discriminating the same states.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 16:53:47 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 16:29:55 GMT"
},
{
"version": "v3",
"created": "Wed, 26 Sep 2007 15:46:10 GMT"
},
{
"version": "v4",
"created": "Fri, 30 Nov 2007 00:49:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Qiu",
"Daowen",
""
]
] |
0707.3971 | Sergei V. Kalinin | Sergei V. Kalinin and Vincent Meunien | Quantum Flexoelectricity in Low Dimensional Systems | 15 pages, 3 figures | null | 10.1103/PhysRevB.77.033403 | null | cond-mat.mtrl-sci | null | Symmetry breaking at surfaces and interfaces and the capability to support
large strain gradients in nanoscale systems enable new forms of
electromechanical coupling. Here we introduce the concept of quantum
flexoelectricity, a phenomenon that is manifested when the mechanical
deformation of non-polar quantum systems results in the emergence of net dipole
moments and hence linear electromechanical coupling proportional to local
curvature. The concept is illustrated in carbon systems, including
polyacetylene and nano graphitic ribbons. Using density functional theory
calculations for systems made of up to 400 atoms, we determine the
flexoelectric coefficients to be of the order of ~ 0.1 e, in agreement with the
prediction of linear theory. The implications of quantum flexoelectricity on
electromechanical device applications, and physics of carbon based materials
are discussed.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:01:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kalinin",
"Sergei V.",
""
],
[
"Meunien",
"Vincent",
""
]
] |
0707.3972 | Ted Pedersen | Ted Pedersen | Learning Probabilistic Models of Word Sense Disambiguation | 195 pages | PhD dissertation, May 1998, Department of Computer Science and
Engineering, Southern Methodist University | null | null | cs.CL cs.AI | null | This dissertation presents several new methods of supervised and unsupervised
learning of word sense disambiguation models. The supervised methods focus on
performing model searches through a space of probabilistic models, and the
unsupervised methods rely on the use of Gibbs Sampling and the Expectation
Maximization (EM) algorithm. In both the supervised and unsupervised case, the
Naive Bayesian model is found to perform well. An explanation for this success
is presented in terms of learning rates and bias-variance decompositions.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:02:40 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Pedersen",
"Ted",
""
]
] |
0707.3973 | Ali Goker | A. Goker, B. A. Friedman and P. Nordlander | Transient current in a quantum dot asymmetrically coupled to metallic
leads | 11 pages, 5 figures; to appear in J. Phys. Condens. Matter | null | 10.1088/0953-8984/19/37/376206 | null | cond-mat.str-el | null | The time-dependent non-crossing approximation is used to study the transient
current in a single electron transistor attached asymmetrically to two leads
following a sudden change in the energy of the dot level. We show that for
asymmetric coupling, sharp features in the density of states of the leads can
induce oscillations in the current through the dot. These oscillations persist
to much longer timescales than the timescale for charge fluctuations. The
amplitude of the oscillations increases as the temperature or source-drain bias
across the dot is reduced and saturates for values below the Kondo temperature.
We discuss the microscopic origin of these oscillations and comment on the
possibility for their experimental detection.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:13:50 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Goker",
"A.",
""
],
[
"Friedman",
"B. A.",
""
],
[
"Nordlander",
"P.",
""
]
] |
0707.3974 | Jozsef Cserti | P. Rakyta, L. Oroszlany, A. Kormanyos, C. J. Lambert and J. Cserti | Peculiar Nature of Snake States in Graphene | 4 pages, 5 figures | Phys. Rev. B 77, 081403(R) (2008) | 10.1103/PhysRevB.77.081403 | null | cond-mat.mes-hall | null | We study the dynamics of the electrons in a non-uniform magnetic field
applied perpendicular to a graphene sheet in the low energy limit when the
excitation states can be described by a Dirac type Hamiltonian. We show that as
compared to the two-dimensional electron gas (2DEG) snake states in graphene
exibit peculiar properties related to the underlying dynamics of the Dirac
fermions. The current carried by snake states is locally uncompensated even if
the Fermi energy lies between the first non-zero energy Landau levels of the
conduction and valence bands. The nature of these states is studied by
calculating the current density distribution. It is shown that besides the
snake states in finite samples surface states also exist.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:14:18 GMT"
}
] | 2008-02-22T00:00:00 | [
[
"Rakyta",
"P.",
""
],
[
"Oroszlany",
"L.",
""
],
[
"Kormanyos",
"A.",
""
],
[
"Lambert",
"C. J.",
""
],
[
"Cserti",
"J.",
""
]
] |
0707.3975 | Nicola Romanazzi | Christophe Letellier (CORIA), Robert Gilmore (Drexel U., CORIA),
Timothy Jones (Drexel U.) | Peeling Bifurcations of Toroidal Chaotic Attractors | 7 pages, 14 figures, accepted to Physical Review E | null | 10.1103/PhysRevE.76.066204 | null | nlin.CD | null | Chaotic attractors with toroidal topology (van der Pol attractor) have
counterparts with symmetry that exhibit unfamiliar phenomena. We investigate
double covers of toroidal attractors, discuss changes in their morphology under
correlated peeling bifurcations, describe their topological structures and the
changes undergone as a symmetry axis crosses the original attractor, and
indicate how the symbol name of a trajectory in the original lifts to one in
the cover. Covering orbits are described using a powerful synthesis of kneading
theory with refinements of the circle map. These methods are applied to a
simple version of the van der Pol oscillator.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:22:09 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 13:16:29 GMT"
},
{
"version": "v3",
"created": "Wed, 17 Oct 2007 22:55:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Letellier",
"Christophe",
"",
"CORIA"
],
[
"Gilmore",
"Robert",
"",
"Drexel U., CORIA"
],
[
"Jones",
"Timothy",
"",
"Drexel U."
]
] |
0707.3976 | H{\aa}vard Haugen | H. Haugen, Daniel Huertas-Hernando and Arne Brataas | Spin transport in proximity induced ferromagnetic graphene | 9 pages, 11 figures | Phys. Rev. B 77, 115406 (2008) | 10.1103/PhysRevB.77.115406 | null | cond-mat.mes-hall | null | Magnetic gates in close proximity to graphene can induce ferromagnetic
correlations. We study the effect of such induced magnetization dependent
Zeeman splittings on the graphene transport properties. We estimate that
induced spin splittings of the order of \Delta ~ 5 meV could be achieved with
the use of magnetic insulator gates, e.g. EuO-gates, deposited on top of
graphene. We demonstrate that such splittings in proximity induced
ferromagnetic graphene could be determined directly from the tunneling
resonances in the linear response conductance, as the top gate creates also a
tunable barrier in the graphene layer. We show how such splittings could also
be determined independently by magnetoresistance measurements in a spin-valve
geometry. Because the spin polarization of the current near the Dirac point
increases with the length of the barrier, long magnetic gates are desirable for
determining \Delta experimentally.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:48:52 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Mar 2008 13:18:24 GMT"
}
] | 2008-03-07T00:00:00 | [
[
"Haugen",
"H.",
""
],
[
"Huertas-Hernando",
"Daniel",
""
],
[
"Brataas",
"Arne",
""
]
] |
0707.3977 | Andrew Norris | Andrew N. Norris | The worm-like chain model at small and large stretch | 7 pages, 5 figures | null | null | null | cond-mat.mtrl-sci | null | The relation between force and stretch in the worm-like chain model of
entropic elasticity is examined. Although no closed-form expression is valid
for all values of forcing, solutions in the form of asymptotic series can be
obtained under conditions of small and large applied force. The small and large
stretch limits correspond to regular and boundary layer perturbation problems,
respectively. The perturbation problems are solved and series solutions
obtained for force as a function of stretch. The form of the asymptotic series
suggest a uniform approximation valid for all stretch that is an improvement on
existing approximations.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:46:04 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Norris",
"Andrew N.",
""
]
] |
0707.3978 | Bin Chen | Bin Chen, Wei He, Jun-Bao Wu and Liang Zhang | M5-branes and Wilson Surfaces | 30 pages, Latex; little revision;Typos corrected, references added,
JHEP published version | JHEP0708:067,2007 | 10.1088/1126-6708/2007/08/067 | SISSA-48/2007/EP | hep-th | null | We investigate the M5-brane description of the Wilson surface operators in
six-dimensional (2,0) superconformal field theory from AdS/CFT correspondence.
We consider the Wilson surface operators in high-dimensional representation,
whose description could be M5-brane string soliton solutions in $AdS_7\times
S^4$ background. We construct such string soliton solutions from the covariant
M5-brane equations of motion and discuss their properties. The supersymmetry
analysis shows that these solutions are half-BPS. We also discuss the subtle
issue on the boundary terms.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 17:52:56 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 18:19:32 GMT"
},
{
"version": "v3",
"created": "Sat, 25 Aug 2007 13:27:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chen",
"Bin",
""
],
[
"He",
"Wei",
""
],
[
"Wu",
"Jun-Bao",
""
],
[
"Zhang",
"Liang",
""
]
] |
0707.3979 | Refugio Vallejo | Isidro B. Nieto and J. Refugio Vallejo | Clifford Algebra of the Vector Space of Conics for decision boundary
Hyperplanes in m-Euclidean Space | 12 pages, 2 figures, 1 table | null | null | null | cs.NE cs.CG | null | In this paper we embed $m$-dimensional Euclidean space in the geometric
algebra $Cl_m $ to extend the operators of incidence in ${R^m}$ to operators of
incidence in the geometric algebra to generalize the notion of separator to a
decision boundary hyperconic in the Clifford algebra of hyperconic sections
denoted as ${Cl}({Co}_{2})$. This allows us to extend the concept of a linear
perceptron or the spherical perceptron in conformal geometry and introduce the
more general conic perceptron, namely the {elliptical perceptron}. Using
Clifford duality a vector orthogonal to the decision boundary hyperplane is
determined. Experimental results are shown in 2-dimensional Euclidean space
where we separate data that are naturally separated by some typical plane conic
separators by this procedure. This procedure is more general in the sense that
it is independent of the dimension of the input data and hence we can speak of
the hyperconic elliptic perceptron.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 18:03:23 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Nieto",
"Isidro B.",
""
],
[
"Vallejo",
"J. Refugio",
""
]
] |
0707.3980 | Davide Donato | R. M. Sambruna (1), D. Donato (1), F. Tavecchio (2), L. Maraschi (2),
C. C. Cheung (3), C. M. Urry (4) ((1) NASA/GSFC; (2) INAF-Osservatorio
Astronomico di Brera; (3) NRAO and Stanford; (4) Yale) | Deep Chandra and multicolor HST observations of the jets of 3C 371 and
PKS 2201+044 | Accepted for publication in ApJ; 28 pages (emulateapj5), 17 figures | null | 10.1086/521972 | null | astro-ph | null | This paper presents multiwavelength imaging and broad-band spectroscopy of
the relativistic jets in the two nearby radio galaxies 3C 371 and PKS 2201+044,
acquired with Chandra, HST, VLA, and Merlin. Radio polarization images are also
available. The two sources stand out as "intermediate'' between FRIs and FRIIs;
their cores are classified as BL Lacs, although broad and narrow optical
emission lines were detected at times. The multiwavelength images show jet
morphologies with the X-ray emission peaking closer to the nucleus than the
longer wavelengths. The jets are resolved at all wavelengths in a direction
perpendicular to the jet axis. The jets SEDs are consistent with a single
spectral component from radio to X-rays, interpreted as synchrotron emission.
The SEDs show a progressive softening from the inner to the outer regions of
the jet, indicating that the electron break energy moves to lower energies with
distance from the core. Overall, the X-ray and multiwavelength properties of
the jets of 3C 371 and PKS 2201+044 appear intermediate between those of FRIs
and FRIIs.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 18:03:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sambruna",
"R. M.",
""
],
[
"Donato",
"D.",
""
],
[
"Tavecchio",
"F.",
""
],
[
"Maraschi",
"L.",
""
],
[
"Cheung",
"C. C.",
""
],
[
"Urry",
"C. M.",
""
]
] |
0707.3981 | Stefan Ulrych | S. Ulrych | Representations of Clifford algebras with hyperbolic numbers | 20 pages Latex2e; minor changes | Adv. Appl. Clifford Algebras 18:93-114 (2008) | 10.1007/s00006-007-0057-4 | null | math-ph gr-qc hep-th math.MP | null | The representations of Clifford algebras and their involutions and
anti-involutions are fully investigated since decades. However, these
representations do sometimes not comply with usual conventions within physics.
A few simple examples are presented, which point out that the hyperbolic
numbers can close this gap.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 18:12:21 GMT"
},
{
"version": "v2",
"created": "Sat, 15 Sep 2007 15:45:21 GMT"
}
] | 2014-07-01T00:00:00 | [
[
"Ulrych",
"S.",
""
]
] |
0707.3982 | Kuang-Ta Chao | Kuang-Ta Chao | Interpretations for the X(4160) observed in the double charm production
at B factories | version to appear in Phys. Lette. B, discussions and references added | Phys.Lett.B661:348-353,2008 | 10.1016/j.physletb.2008.02.039 | null | hep-ph hep-ex | null | Belle Collaboration has recently observed a new state, the X(4160), in the
process of double charm production $e^+e^-\to J/\psi+X(4160)$ followed by
$X(4160)\to D^*\bar{D^*}$. We discuss possible interpretations for the X(4160)
based on the NRQCD calculations and the potential model estimates for the
charmonium spectrum. We first focus on the D-wave spin-singlet $2^{-+}$
charmonium $^1D_2(2D)$, which is estimated to have a small production rate of
about 5% of that for $e^+e^-\to J/\psi+\eta_c(1S)$, and therefore is
incompatible with the observed data for X(4160). We then discuss the
possibility that the X(4160) is the known $J^{PC}=1^{--}$ charmonium state
$\psi(4160)$, which can be produced via two photon fragmentation, but the
production rate is much smaller than observed for $e^+e^-\to J/\psi+X(4160)$.
In contrast to above two possibilities, the $\eta_c(4S)$ assignment is a likely
one, which is supported by the observed relatively large production rate and
non-observation of $D\bar D$ decay of X(4160), but we have to understand why
$\eta_c(4S)$ has such a low mass, which deserves further studies. The P-wave
excited state $\chi_{c0}(3P)$ is also an interesting candidate, if the observed
broad peak around 3.8-3.9 GeV in the recoil mass of $D\bar D$ against $J/\psi$
in $e^++e^-\to J/\psi+D\bar D$ is due to the $\chi_{c0}(2P)$ state.
Measurements of production angular distributions will be helpful to distinguish
between $\eta_c(4S)$ and $\chi_{c0}(3P)$ assignments. Production mechanisms in
nonrelativistic QCD are emphasized.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 18:57:43 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Aug 2007 19:42:35 GMT"
},
{
"version": "v3",
"created": "Thu, 21 Feb 2008 04:35:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chao",
"Kuang-Ta",
""
]
] |
0707.3983 | Daniel Litim | Daniel F. Litim, Tilman Plehn | Signatures of gravitational fixed points at the LHC | 4 pages, 3 figures; v2: error in numerics corrected (Tab. 1), typos
removed; v3: comment added, version to appear in Phys. Rev. Lett | Phys.Rev.Lett.100:131301,2008 | 10.1103/PhysRevLett.100.131301 | CERN-TH-PH-2007-127 | hep-ph gr-qc hep-th | null | We study quantum-gravitational signatures at the Large Hadron Collider (LHC)
in the context of theories with extra spatial dimensions and a low fundamental
Planck scale in the TeV range. Implications of a gravitational fixed point at
high energies are worked out using Wilson's renormalisation group. We find that
relevant cross-sections involving virtual gravitons become finite. Based on
gravitational lepton pair production we conclude that the LHC is sensitive to a
fundamental Planck scale of up to 6 TeV.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:01:54 GMT"
},
{
"version": "v2",
"created": "Mon, 27 Aug 2007 17:39:15 GMT"
},
{
"version": "v3",
"created": "Thu, 21 Feb 2008 21:55:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Litim",
"Daniel F.",
""
],
[
"Plehn",
"Tilman",
""
]
] |
0707.3984 | Satoru Konabe | Satoru Konabe and Tetsuro Nikuni | Coarse-Grained Finite-Temperature Theory for the Condensate in Optical
Lattices | 38 pages, 2 figures. Submitted to Journal of Low Temperature Physics | Journal of Low Temperature Physics 150, 12 (2008) | 10.1007/s10909-007-9517-4 | null | cond-mat.other | null | In this work, we derive a coarse-grained finite-temperature theory for a Bose
condensate in a one-dimensional optical lattice, in addition to a confining
harmonic trap potential. We start from a two-particle irreducible (2PI)
effective action on the Schwinger-Keldysh closed-time contour path. In
principle, this action involves all information of equilibrium and
non-equilibrium properties of the condensate and noncondensate atoms. By
assuming an ansatz for the variational function, i.e., the condensate order
parameter in an effective action, we derive a coarse-grained effective action,
which describes the dynamics on the length scale much longer than a lattice
constant. Using the variational principle, coarse-grained equations of motion
for the condensate variables are obtained. These equations include a
dissipative term due to collisions between condensate and noncondensate atoms,
as well as noncondensate mean-field. To illustrate the usefulness of our
formalism, we discuss a Landau instability of the condensate in optical
lattices by using the coarse-grained generalized Gross-Pitaevskii
hydrodynamics. We found that the collisional damping rate due to collisions
between the condensate and noncondensate atoms changes sign when the condensate
velocity exceeds a renormalized sound velocity, leading to a Landau instability
consistent with the Landau criterion. Our results in this work give an insight
into the microscopic origin of the Landau instability.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:04:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Konabe",
"Satoru",
""
],
[
"Nikuni",
"Tetsuro",
""
]
] |
0707.3985 | Immanuel Bloch | S. Foelling, S. Trotzky, P. Cheinet, M. Feld, R. Saers, A. Widera, T.
Mueller and I. Bloch | Direct Observation of Second Order Atom Tunnelling | 18 pages, 4 figures, accepted for publication in Nature | Nature, 448, p. 1029-1032 (2007) | 10.1038/nature06112 | null | cond-mat.other quant-ph | null | Tunnelling of material particles through a classically impenetrable barrier
constitutes one of the hallmark effects of quantum physics. When interactions
between the particles compete with their mobility through a tunnel junction,
intriguing novel dynamical behaviour can arise where particles do not tunnel
independently. In single-electron or Bloch transistors, for example, the
tunnelling of an electron or Cooper pair can be enabled or suppressed by the
presence of a second charge carrier due to Coulomb blockade. Here we report on
the first direct and time-resolved observation of correlated tunnelling of two
interacting atoms through a barrier in a double well potential. We show that
for weak interactions between the atoms and dominating tunnel coupling,
individual atoms can tunnel independently, similar to the case in a normal
Josephson junction. With strong repulsive interactions present, two atoms
located on one side of the barrier cannot separate, but are observed to tunnel
together as a pair in a second order co-tunnelling process. By recording both
the atom position and phase coherence over time, we fully characterize the
tunnelling process for a single atom as well as the correlated dynamics of a
pair of atoms for weak and strong interactions. In addition, we identify a
conditional tunnelling regime, where a single atom can only tunnel in the
presence of a second particle, acting as a single atom switch. Our work
constitutes the first direct observation of second order tunnelling events with
ultracold atoms, which are the dominating dynamical effect in the strongly
interacting regime. Similar second-order processes form the basis of
superexchange interactions between atoms on neighbouring lattice sites of a
periodic potential, a central component of quantum magnetism.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:07:12 GMT"
}
] | 2010-04-06T00:00:00 | [
[
"Foelling",
"S.",
""
],
[
"Trotzky",
"S.",
""
],
[
"Cheinet",
"P.",
""
],
[
"Feld",
"M.",
""
],
[
"Saers",
"R.",
""
],
[
"Widera",
"A.",
""
],
[
"Mueller",
"T.",
""
],
[
"Bloch",
"I.",
""
]
] |
0707.3986 | Bruno Cernuschi-Frias | Bruno Cernuschi-Frias (IRISA) | Mixed States Markov Random Fields with Symbolic Labels and
Multidimensional Real Values | null | null | null | null | math.PR | null | New theoretical results are presented here on the recently introduced model
called mixed states MRF. Such models were introduced in the context of image
motion analysis and are useful to represent information which can take both
discrete values accounting for symbolic states, and real values corresponding
to continuous measurements. In particular, results are given when the global
energy for the Gibbs formulation expressing the mixed states model, can be
decomposed into one term accounting for the discrete part of the model, and a
second term related to the continuous part. This decomposition theorem permits
to define conditional mixed states models in a very simple way.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:08:25 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 12:55:55 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Cernuschi-Frias",
"Bruno",
"",
"IRISA"
]
] |
0707.3987 | Vadim Makarov | Vadim Makarov | Controlling passively-quenched single photon detectors by bright light | Experimental results from a third detector model added. Minor
corrections and edits made. 11 pages, 10 figures | New J. Phys. 11, 065003 (2009) | 10.1088/1367-2630/11/6/065003 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Single photon detectors based on passively-quenched avalanche photodiodes can
be temporarily blinded by relatively bright light, of intensity less than a
nanowatt. I describe a bright-light regime suitable for attacking a quantum key
distribution system containing such detectors. In this regime, all single
photon detectors in the receiver Bob are uniformly blinded by continuous
illumination coming from the eavesdropper Eve. When Eve needs a certain
detector in Bob to produce a click, she modifies polarization (or other
parameter used to encode quantum states) of the light she sends to Bob such
that the target detector stops receiving light while the other detector(s)
continue to be illuminated. The target detector regains single photon
sensitivity and, when Eve modifies the polarization again, produces a single
click. Thus, Eve has full control of Bob and can do a successful
intercept-resend attack. To check the feasibility of the attack, 3 different
models of passively-quenched detectors have been tested. In the experiment, I
have simulated the intensity diagrams the detectors would receive in a real
quantum key distribution system under attack. Control parameters and side
effects are considered. It appears that the attack could be practically
possible.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:33:22 GMT"
},
{
"version": "v2",
"created": "Tue, 13 Jan 2009 12:16:16 GMT"
},
{
"version": "v3",
"created": "Fri, 17 Apr 2009 06:31:01 GMT"
}
] | 2009-06-16T00:00:00 | [
[
"Makarov",
"Vadim",
""
]
] |
0707.3988 | G\"unter Stolz | Jeff Baker, Michael Loss, G\"unter Stolz | Minimizing the ground state energy of an electron in a randomly deformed
lattice | 18 pages, 4 figures | null | 10.1007/s00220-008-0507-4 | null | math-ph math.MP | null | We provide a characterization of the spectral minimum for a random
Schr\"odinger operator of the form $H=-\Delta + \sum_{i \in
\Z^d}q(x-i-\omega_i)$ in $L^2(\R^d)$, where the single site potential $q$ is
reflection symmetric, compactly supported in the unit cube centered at 0, and
the displacement parameters $\omega_i$ are restricted so that adjacent single
site potentials do not overlap. In particular, we show that a minimizing
configuration of the displacements is given by a periodic pattern of densest
possible $2^d$-clusters of single site potentials.
The main tool to prove this is a quite general phenomenon in the spectral
theory of Neumann problems, which we dub ``bubbles tend to the boundary.'' How
should a given compactly supported potential be placed into a bounded domain so
as to minimize or maximize the first Neumann eigenvalue of the Schr\"odinger
operator on this domain? For square or rectangular domains and reflection
symmetric potentials, we show that the first Neumann eigenvalue is minimized
when the potential sits in one of the corners of the domain and is maximized
when it sits in the center of the domain. With different methods we also show a
corresponding result for smooth strictly convex domains.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:15:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Baker",
"Jeff",
""
],
[
"Loss",
"Michael",
""
],
[
"Stolz",
"Günter",
""
]
] |
0707.3989 | Johan Segers | Bojan Basrak, Johan Segers | Regularly varying multivariate time series | 25 pages | null | null | null | math.PR math.ST stat.TH | null | A multivariate, stationary time series is said to be jointly regularly
varying if all its finite-dimensional distributions are multivariate regularly
varying. This property is shown to be equivalent to weak convergence of the
conditional distribution of the rescaled series given that, at a fixed time
instant, its distance to the origin exceeds a threshold tending to infinity.
The limit object, called the tail process, admits a decomposition in
independent radial and angular components. Under an appropriate mixing
condition, this tail process allows for a concise and explicit description of
the limit of a sequence of point processes recording both the times and the
positions of the time series when it is far away from the origin. The theory is
applied to multivariate moving averages of finite order with random coefficient
matrices.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:20:02 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 20:19:48 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Basrak",
"Bojan",
""
],
[
"Segers",
"Johan",
""
]
] |
0707.3990 | Alexander Bolonkin | Alexander Bolonkin | Inflatable Dome for Moon, Mars, Asteroids and Satellites | 11 pages, 7 figures, 2 tables | null | null | null | physics.gen-ph physics.space-ph | null | On a planet without atmosphere, sustaining human life is very difficult and
dangerous, especially during short sunlit period when low temperature prevails.
To counter these environmental stresses, the author offer an innovative
artificial "Evergreen" dome, an inflated hemisphere with interiors continuously
providing a climate like that of Florida, Italy and Spain. The "Evergreen" dome
theory is developed, substantiated by computations that show it is possible for
current technology to construct and heat large enclosed volumes inexpensively.
Specifically, a satisfactory result is reached by using magnetic suspended at
high altitude sunlight reflectors and a special double thin film as a skin,
which concentrates solar energy inside the dome while, at the same time,
markedly decreasing the heat loss to exterior space. Offered design may be
employed for settlements on the Moon, Mars, asteroids and satellites.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:28:53 GMT"
}
] | 2007-07-27T00:00:00 | [
[
"Bolonkin",
"Alexander",
""
]
] |
0707.3991 | Pierre-Alain Duc | Pierre-Alain Duc, Frederic Bournaud and Elias Brinks | Tidal Debris posing as Dark Galaxies | 10 pages, 4 figures, to appear in IAU symposium 244 "Dark Galaxies
and Lost Baryons" | null | 10.1017/S1743921307014019 | null | astro-ph | null | Debris sent into the intergalactic medium during tidal collisions can tell us
about several fundamental properties of galaxies, in particular their missing
mass, both in the form of cosmological Dark Matter and so-called Lost Baryons.
High velocity encounters, which are common in clusters of galaxies, are able to
produce faint tidal debris that may appear as star-less, free floating HI
clouds. These may be mistaken for Dark Galaxies, a putative class of gaseous,
dark matter dominated, objects which for some reason never managed to form
stars. VirgoHI21 is by far the most spectacular and most discussed Dark Galaxy
candidate so far detected in HI surveys. We show here that it is most likely
made out of material expelled 750 Myr ago from the nearby spiral galaxy NGC
4254 during its fly--by at about 1000 km/s by a massive intruder. Our numerical
model of the collision is able to reproduce the main characteristics of the
system: in particular the absence of stars, and its prominent velocity
gradient. Originally attributed to the gas being in rotation within a massive
dark matter halo, we find it instead to be consistent with a combination of
simple streaming motion plus projection effects (Duc & Bournaud, 2007). We
discuss several ways to identify a tidal origin in a Dark Galaxy candidate and
illustrate the method using another HI system in Virgo, VCC 2062, which is most
likely a Tidal Dwarf Galaxy (Duc et al., 2007). Now, whereas tidal debris
should not contain any dark matter from the halo of their parent galaxies, it
may exhibit missing mass in the form of dark baryons, unaccounted for by
classical observations, as recently found in the collisional ring of NGC 5291
(Bournaud et al., 2007) and probably in the TDG VCC 2062. These "Lost Baryons"
must originally have been located in the disks of their parent galaxies.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:29:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Duc",
"Pierre-Alain",
""
],
[
"Bournaud",
"Frederic",
""
],
[
"Brinks",
"Elias",
""
]
] |
0707.3992 | Arkady Kholodenko L. | Arkady L. Kholodenko | Quantum Signatures of Solar System Dynamics | 61 pages, revised and updated | null | null | null | physics.gen-ph physics.space-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let w(i) be a period of rotation of the i-th planet around the Sun (or w(j;i)
be a period of rotation of j-th satellite around the i-th planet). From
empirical observations it is known that the sum of n(i)w(i)=0 (or the sum of
n(j)w(j;i)=0) for some integers n(i) (or n(j)), different for different
satellite systems. These conditions, known as resonance conditions, make uses
of theories such as KAM difficult to implement. The resonances in Solar System
are similar to those encountered in old quantum mechanics where applications of
methods of celestial mechanics to atomic and molecular physics were highly
sucsessful. With such a success, the birth of new quantum mechanics is
difficult to understand. In short, the rationale for its birth lies in
simplicity with which the same type of calculations are done using new methods
capable of taking care of resonances. The solution of quantization puzzle was
found by Heisenberg. In this paper new uses of Heisenberg's ideas are found.
When superimposed with the equivalence principle of general relativity, they
lead to quantum mechanical tratment of observed resonances in Solar System. To
test correctness of our theoretical predictions the number of allowed stable
orbits for planets and for equatorial stable orbits of satellites of heavy
planets is calculated resulting in good agreement with observational data. In
addition, the paper briefly discusses quantum mechanical nature of rings of
heavy planets and potential usefulness of the obtained results for cosmology.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:43:15 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Aug 2007 20:53:50 GMT"
},
{
"version": "v3",
"created": "Thu, 20 Sep 2007 21:30:23 GMT"
},
{
"version": "v4",
"created": "Fri, 17 Oct 2008 22:26:27 GMT"
}
] | 2008-10-18T00:00:00 | [
[
"Kholodenko",
"Arkady L.",
""
]
] |
0707.3993 | Alexander Smirnov | A. V. Smirnov, V. A. Smirnov | On the reduction of Feynman integrals to master integrals | 8 pages, proceedings of ACAT07 | PoSACAT2007:085,2007 | null | null | hep-ph | null | The reduction of Feynman integrals to master integrals is an algebraic
problem that requires algorithmic approaches at the modern level of
calculations. Straightforward applications of the classical Buchberger
algorithm to construct Groebner bases seem to be inefficient. An essential
modification designed especially for this problem has been worked out. It has
been already applied in two- and three-loop calculations. We are also
suggesting to combine our method with the Laporta's algorithm.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:45:16 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Smirnov",
"A. V.",
""
],
[
"Smirnov",
"V. A.",
""
]
] |
0707.3994 | Boris V. Fine | Boris V. Fine and Takeshi Egami | Phase separation in the vicinity of "quantum critical" doping
concentration: implications for high temperature superconductors | null | Phys. Rev. B 77, 014519 (2008) | 10.1103/PhysRevB.77.014519 | null | cond-mat.str-el cond-mat.stat-mech cond-mat.supr-con | null | A general quantitative measure of the tendency towards phase separation is
introduced for systems exhibiting phase transitions or crossovers controlled by
charge carrier concentration. This measure is devised for the situations when
the quantitative knowledge of various contributions to free energy is
incomplete, and is applied to evaluate the chances of electronic phase
separation associated with the onset of antiferromagnetic correlations in
high-temperature cuprate superconductors. The experimental phenomenology of
lanthanum- and yittrium-based cuprates was used as input to this analysis. It
is also pointed out that Coulomb repulsion between charge carriers separated by
the distances of 1-3 lattice periods strengthens the tendency towards phase
separation by accelerating the decay of antiferromagnetic correlations with
doping. Overall, the present analysis indicates that cuprates are realistically
close to the threshold of phase separation -- nanoscale limited or even
macroscopic with charge density varying between adjacent crystal planes.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:49:09 GMT"
}
] | 2011-05-02T00:00:00 | [
[
"Fine",
"Boris V.",
""
],
[
"Egami",
"Takeshi",
""
]
] |
0707.3995 | Kam Tuen Law | K. T. Law | Probing Non-Abelian Statistics in nu=12/5 Quantum Hall State | 10 pages, 6 figures | Phys. Rev. B 77, 205310 (2008) | 10.1103/PhysRevB.77.205310 | null | cond-mat.mes-hall | null | The tunneling current and shot noise of the current between two Fractional
Quantum Hall (FQH) edges in the $ \nu=12/5 $ FQH state in electronic
Mach-Zehnder interferometer are studied. It is shown that the tunneling current
and shot noise can be used to probe the existence of $k=3 $ parafermion
statistics in the $ \nu=12/5 $ FQH state. More specifically, the dependence of
the current on the Aharonov-Bohm flux in the Read-Rezayi state is asymmetric
under the change of the sign of the applied voltage. This property is absent in
the Abelian Laughlin states. Moreover the Fano factor can exceed 12.7 electron
charges in the $ \nu=12/5 $ FQH state . This number well exceeds the maximum
possible Fano factor in all Laughlin states and the $ \nu=5/2 $ Moore-Read
state which was shown previously to be $ e $ and $ 3.2 e $ respectively.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:50:17 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 04:28:45 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jan 2008 18:07:48 GMT"
}
] | 2011-10-21T00:00:00 | [
[
"Law",
"K. T.",
""
]
] |
0707.3996 | Jean-Marc Richard | J. Vijande, A. Valcarce and J.-M. Richard | Stability of multiquarks in a simple string model | 4 pages, 2 figures, Refs. added, typos corrected, discussion
improved, to appear in Phys. Rev. D | Phys.Rev.D76:114013,2007 | 10.1103/PhysRevD.76.114013 | null | hep-ph nucl-th | null | A simple string model inspired by the strong-coupling regime of Quantum
ChromoDynamics is used as a potential for studying the spectrum of multiquark
systems with two quarks and two antiquarks, with a careful treatment of the
four-body problem. It is found that the ground state is stable, lying below the
threshold for dissociation into two isolated mesons.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:55:22 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Oct 2007 14:08:16 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Vijande",
"J.",
""
],
[
"Valcarce",
"A.",
""
],
[
"Richard",
"J. -M.",
""
]
] |
0707.3997 | Peter Tamburello | D0 Collaboration: V. Abazov, et al | Search for Bs --> mu+ mu- at D0 | submitted to PRD-RC | Phys.Rev.D76:092001,2007 | 10.1103/PhysRevD.76.092001 | FERMILAB-PUB-07-395-E | hep-ex | null | We report results from a search for the decay Bs --> mu+ mu- using 1.3/fb of
pbar p collisions at sqrt(s)= 1.96 TeV collected by the D0 experiment at the
Fermilab Tevatron Collider. We find two candidate events, consistent with the
expected background of 1.24 +/- 0.99, and set an upper limit on the branching
fraction of B(Bs --> mu+ mu-) < 1.2e-7 at the 95% C.L.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 19:57:06 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"D0 Collaboration",
"",
""
],
[
"Abazov",
"V.",
""
]
] |
0707.3998 | Joshua Simon | Joshua D. Simon (Caltech), Alberto D. Bolatto (UC Berkeley), Barbara
A. Whitney (Space Science Institute), Thomas P. Robitaille (SUPA, St.
Andrews), Ronak Y. Shah (Boston University), David Makovoz (Spitzer Science
Center), Snezana Stanimirovic (Wisconsin), Rodolfo H. Barba (Universidad de
La Serena), and Monica Rubio (Universidad de Chile) | The Spitzer Survey of the Small Magellanic Cloud: Discovery of Embedded
Protostars in the HII Region NGC 346 | 13 pages, 5 figures (3 in color), 2 tables. Accepted for publication
in ApJ | Astrophys.J.669:327-336,2007 | 10.1086/521544 | null | astro-ph | null | We use Spitzer Space Telescope observations from the Spitzer Survey of the
Small Magellanic Cloud (S3MC) to study the young stellar content of N66, the
largest and brightest HII region in the SMC. In addition to large numbers of
normal stars, we detect a significant population of bright, red infrared
sources that we identify as likely to be young stellar objects (YSOs). We use
spectral energy distribution (SED) fits to classify objects as ordinary (main
sequence or red giant) stars, asymptotic giant branch stars, background
galaxies, and YSOs. This represents the first large-scale attempt at blind
source classification based on Spitzer SEDs in another galaxy. We firmly
identify at least 61 YSOs, with another 50 probable YSOs; only one embedded
protostar in the SMC was reported in the literature prior to the S3MC. We
present color selection criteria that can be used to identify a relatively
clean sample of YSOs with IRAC photometry. Our fitted SEDs indicate that the
infrared-bright YSOs in N66 have stellar masses ranging from 2 Msun to 17 Msun,
and that approximately half of the objects are Stage II protostars, with the
remaining YSOs roughly evenly divided between Stage I and Stage III sources. We
find evidence for primordial mass segregation in the HII region, with the most
massive YSOs being preferentially closer to the center than lower-mass objects.
Despite the low metallicity and dust content of the SMC, the observable
properties of the YSOs appear consistent with those in the Milky Way. Although
the YSOs are heavily concentrated within the optically bright central region of
N66, there is ongoing star formation throughout the complex and we place a
lower limit on the star formation rate of 3.2 x 10^-3 Msun/yr over the last ~1
Myr.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:00:03 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Simon",
"Joshua D.",
"",
"Caltech"
],
[
"Bolatto",
"Alberto D.",
"",
"UC Berkeley"
],
[
"Whitney",
"Barbara A.",
"",
"Space Science Institute"
],
[
"Robitaille",
"Thomas P.",
"",
"SUPA, St.\n Andrews"
],
[
"Shah",
"Ronak Y.",
"",
"Boston University"
],
[
"Makovoz",
"David",
"",
"Spitzer Science\n Center"
],
[
"Stanimirovic",
"Snezana",
"",
"Wisconsin"
],
[
"Barba",
"Rodolfo H.",
"",
"Universidad de\n La Serena"
],
[
"Rubio",
"Monica",
"",
"Universidad de Chile"
]
] |
0707.3999 | Joseph D. Lykken | Gabriela Barenboim and Joseph D. Lykken | Quintessence, inflation and baryogenesis from a single
pseudo-Nambu-Goldstone boson | 16 pages, 3 color figures | JHEP 0710:032,2007 | 10.1088/1126-6708/2007/10/032 | FERMILAB-PUB-07-211-T, FTUV 07-0618 | astro-ph | null | We exhibit a model in which a single pseudo-Nambu-Goldstone boson explains
dark energy, inflation and baryogenesis. The model predicts correlated signals
in future collider experiments, WIMP searches, proton decay experiments, dark
energy probes, and the PLANCK satellite CMB measurements.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:00:05 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Barenboim",
"Gabriela",
""
],
[
"Lykken",
"Joseph D.",
""
]
] |
0707.4000 | David Gross | D. Gross, M. Van den Nest | The LU-LC conjecture, diagonal local operations and quadratic forms over
GF(2) | 24 pages. Reference added | Quantum Inf. Comput. 8, 263 (2008) | null | null | quant-ph | null | We report progress on the LU-LC conjecture - an open problem in the context
of entanglement in stabilizer states (or graph states). This conjecture states
that every two stabilizer states which are related by a local unitary
operation, must also be related by a local operation within the Clifford group.
The contribution of this paper is a reduction of the LU-LC conjecture to a
simpler problem - which, however, remains to date unsolved. As our main result,
we show that, if the LU-LC conjecture could be proved for the restricted case
of diagonal local unitary operations, then the conjecture is correct in its
totality. Furthermore, the reduced version of the problem, involving such
diagonal local operations, is mapped to questions regarding quadratic forms
over the finite field GF(2). Finally, we prove that correctness of the LU-LC
conjecture for stabilizer states implies a similar result for the more general
case of stabilizer codes.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 18:24:06 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 10:04:55 GMT"
}
] | 2007-12-17T00:00:00 | [
[
"Gross",
"D.",
""
],
[
"Nest",
"M. Van den",
""
]
] |
0707.4001 | Renato A. Dupke | Renato A. Dupke (University of Michigan, Ann Arbor), Raymond E. White
III (University of Alabama, Tuscaloosa), Joel N. Bregman (University of
Michigan, Ann Arbor) | Different Methods of Forming Cold Fronts in Non-Merging Clusters | 11 ApJ pages, 1 Table, 16 Figures, accepted for publication in the
Astrophysical Journal. For full version with all hi-res figures click on
http://www.astro.lsa.umich.edu/~rdupke/a496sub.pdf | null | 10.1086/522194 | null | astro-ph | null | Sharp edges in X-ray surface brightness with continuous gas pressure called
cold fronts have been often found in relaxed galaxy clusters such as Abell 496.
Models that explain cold fronts as surviving cores of head-on subcluster
mergers do not work well for these clusters and competing models involving gas
sloshing have been recently proposed. Here, we test some concrete predictions
of these models in a combined analysis of density, temperature, metal
abundances and abundance ratios in a deep Chandra exposure of Abell 496. We
confirm that the chemical discontinuities found in this cluster are not
consistent with a core merger remnant scenario. However, we find chemical
gradients across a spiral "arm" discovered at 73 kpc north of the cluster
center and coincident with the sharp edge of the main cold front in the
cluster. Despite the overall SN Ia iron mass fraction dominance found within
the cooling radius of this cluster, the metal enrichment along the arm,
determined from silicon and iron abundances, is consistent with a lower SN Ia
iron mass fraction (51% +- 14%) than that measured in the surrounding regions
(85% +- 14%). The "arm" is also significantly colder than the surroundings by
0.5-1.6 keV. The arm extends from a boxy colder region surrounding the center
of the cluster, where two other cold fronts are found. This cold arm is a
prediction of current high resolution numerical simulations as a result of an
off-center encounter with a less massive pure dark matter halo and we suggest
that the cold fronts in A496 provide the first clear corroboration of such
model, where the closest encounter happened ~ 0.5 Gyr ago. We also argue for a
possible candidate dark matter halo responsible for the cold fronts in the
outskirts of A496.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:04:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dupke",
"Renato A.",
"",
"University of Michigan, Ann Arbor"
],
[
"White",
"Raymond E.",
"III",
"University of Alabama, Tuscaloosa"
],
[
"Bregman",
"Joel N.",
"",
"University of\n Michigan, Ann Arbor"
]
] |
0707.4002 | Kieran Cleary | Kieran Cleary (1), Charles R. Lawrence (1), Jason A. Marshall (1), Lei
Hao (2) and David Meier (1) ((1) Caltech/JPL (2) Cornell University) | Spitzer Observations of Powerful Radio Sources | 4 pages, 2 figures. To appear in "The Central Engine of Active
Galactic Nuclei", ed. L.C. Ho and J.-M. Wang, ASP Conference Series | null | null | null | astro-ph | null | We have measured the mid-infrared radiation from an orientation-unbiased
sample of powerful 3C RR galaxies and quasars using the IRS and MIPS
instruments aboard the Spitzer Space Telescope. We fit the Spitzer data as well
as other measurements from the literature with synchrotron and dust components.
At 15 microns, quasars are typically four times brighter than radio galaxies
with the same isotropic radio power. Based on our fits, half of this difference
can be attributed to the presence of non-thermal emission in the quasars but
not the radio galaxies. The other half is consistent with dust absorption in
the radio galaxies but not the quasars.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:18:28 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Cleary",
"Kieran",
"",
"Caltech/JPL"
],
[
"Lawrence",
"Charles R.",
"",
"Caltech/JPL"
],
[
"Marshall",
"Jason A.",
"",
"Caltech/JPL"
],
[
"Hao",
"Lei",
"",
"Cornell University"
],
[
"Meier",
"David",
"",
"Caltech/JPL"
]
] |
0707.4003 | Andrey Lazarev | Alastair Hamilton and Andrey Lazarev | Symplectic $A_\infty$-algebras and string topology operations | Due to a strange glitch in the original submission a wrong TeX file
was uploaded; this version hopefully corrects this error. This paper is a
revision of the part of math.QA/0410621 which deals with string topology type
operations and can be read independently. 9 pages | null | null | null | math.QA math.AT | null | In this paper we establish the existence of certain structures on the
ordinary and equivariant homology of the free loop space on a manifold or, more
generally, a formal Poincar\'e duality space. These structures; namely the loop
product, the loop bracket and the string bracket, were introduced and studied
by Chas and Sullivan under the general heading `string topology'. Our method is
based on obstruction theory for $C_\infty$-algebras and rational homotopy
theory. The resulting string topology operations are manifestly homotopy
invariant.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:45:42 GMT"
},
{
"version": "v2",
"created": "Wed, 15 Aug 2007 15:26:02 GMT"
}
] | 2007-08-15T00:00:00 | [
[
"Hamilton",
"Alastair",
""
],
[
"Lazarev",
"Andrey",
""
]
] |
0707.4004 | Hongyuan Jiang | Hongyuan Jiang, Greg Huber, Robert A. Pelcovits and Thomas R. Powers | Vesicle shape, molecular tilt, and the suppression of necks | 10 pages, 7 figures, submitted to Phy. Rew. E | null | 10.1103/PhysRevE.76.031908 | null | cond-mat.soft | null | Can the presence of molecular-tilt order significantly affect the shapes of
lipid bilayer membranes, particularly membrane shapes with narrow necks?
Motivated by the propensity for tilt order and the common occurrence of narrow
necks in the intermediate stages of biological processes such as endocytosis
and vesicle trafficking, we examine how tilt order inhibits the formation of
necks in the equilibrium shapes of vesicles. For vesicles with a spherical
topology, point defects in the molecular order with a total strength of $+2$
are required. We study axisymmetric shapes and suppose that there is a
unit-strength defect at each pole of the vesicle. The model is further
simplified by the assumption of tilt isotropy: invariance of the energy with
respect to rotations of the molecules about the local membrane normal. This
isotropy condition leads to a minimal coupling of tilt order and curvature,
giving a high energetic cost to regions with Gaussian curvature and tilt order.
Minimizing the elastic free energy with constraints of fixed area and fixed
enclosed volume determines the allowed shapes. Using numerical calculations, we
find several branches of solutions and identify them with the branches
previously known for fluid membranes. We find that tilt order changes the
relative energy of the branches, suppressing thin necks by making them costly,
leading to elongated prolate vesicles as a generic family of tilt-ordered
membrane shapes.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:14:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jiang",
"Hongyuan",
""
],
[
"Huber",
"Greg",
""
],
[
"Pelcovits",
"Robert A.",
""
],
[
"Powers",
"Thomas R.",
""
]
] |
0707.4005 | Philip Hopkins | Philip F. Hopkins (1), Lars Hernquist (1), Thomas J. Cox (1), Brant
Robertson (2), Elisabeth Krause (3) ((1) CfA, (2) KICP, U. Chicago, (3)
Universitat Bonn) | An Observed Fundamental Plane Relation for Supermassive Black Holes | 7 pages, 4 figures, accepted to ApJ. Companion paper to
astro-ph/0701351 | Astrophys.J. 669 (2007) 67-73 | 10.1086/521601 | null | astro-ph | null | We study observed correlations between supermassive black hole (BHs) and the
properties of their host galaxies, and show that the observations define a BH
'fundamental plane' (BHFP), of the form M_BH sigma^(3.0+-0.3)*R_e^(0.43+-0.19),
or M_BH M_bulge^(0.54+-0.17)*sigma^(2.2+-0.5), analogous to the FP of
elliptical galaxies. The BHFP is preferred over a simple relation between M_BH
and any of sigma, M_bulge, M_dyn, or R_e alone at >99.9% significance. The
existence of this BHFP has important implications for the formation of
supermassive BHs and the masses of the very largest black holes, and
immediately resolves several apparent conflicts between the BH masses expected
and measured for outliers in both the M_BH-sigma and M_BH-M_bulge relations.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:15:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hopkins",
"Philip F.",
""
],
[
"Hernquist",
"Lars",
""
],
[
"Cox",
"Thomas J.",
""
],
[
"Robertson",
"Brant",
""
],
[
"Krause",
"Elisabeth",
""
]
] |
0707.4006 | Stepanyantz Konstantin | A. B. Pimenov, K. V. Stepanyantz | Two-loop Gell-Mann-Low function of N=1 supersymmetric Yang-Mills theory,
regularized by higher covariant derivatives | 17 pages, 3 eps figures | Theor.Math.Phys.155:848-861,2008 | 10.1007/s11232-008-0072-1 | null | hep-th | null | Two-loop Gell-Mann-Low function is calculated for N=1 supersymmetric
Yang-Mills theory, regularized by higher covariant derivatives. The integrals,
which define it, are shown to be reduced to total derivatives and can be easily
calculated analytically.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:15:46 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Pimenov",
"A. B.",
""
],
[
"Stepanyantz",
"K. V.",
""
]
] |
0707.4007 | Egon Schulte | Barry Monson and Egon Schulte | Reflection Groups and Polytopes over Finite Fields, III | Advances in Applied Mathematics (to appear); 19 pages | null | null | null | math.CO math.MG | null | When the standard representation of a crystallographic Coxeter group is
reduced modulo an odd prime p, one obtains a finite group G^p acting on some
orthogonal space over Z_p . If the Coxeter group has a string diagram, then G^p
will often be the automorphism group of a finite abstract regular polytope. In
parts I and II we established the basics of this construction and enumerated
the polytopes associated to groups of rank at most 4, as well as all groups of
spherical or Euclidean type. Here we extend the range of our earlier criteria
for the polytopality of G^p . Building on this we investigate the class of
3-infinity groups of general rank, and then complete a survey of those locally
toroidal polytopes which can be described by our construction.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:17:03 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Monson",
"Barry",
""
],
[
"Schulte",
"Egon",
""
]
] |
0707.4008 | Chang-Hwan Lee | G. E. Brown, C. -H. Lee, E. Moreno Mendez | GRBs and Hypernova Explosions of Some Galactic Sources | 5 pages, 1 figures | null | 10.1086/525250 | null | astro-ph | null | Knowing the Kerr parameters we can make quantitative calculations of the
rotational energy of black holes. We show that Nova Sco (GRO J1655 - 40), Il
Lupi (4U 1543 - 47), XTE J1550 - 564 and GS 2023 + 338 are relics of gamma-ray
burst (GRB) and Hypernova explosions. They had more than enough rotational
energy to power themselves. In fact, they had so much energy that they would
have disrupted the accretion disk of the black hole that powered them by the
communicated rotational energy, so that the energy delivery was self limiting.
The most important feature in producing high rotational energy in the binary is
low donor (secondary star) mass.
We suggest that V4641 Sgr (XTE J1819 - 254) and GRS 1915 + 105 underwent less
energetic explosions; because of their large donor masses. These explosions
were one or two orders of magnitude lower in energy than that of Nova Sco. Cyg
X - 1 (1956 + 350) had an even less energetic explosion, because of an even
larger donor mass.
We find that in the evolution of the soft X-ray transient sources the donor
(secondary star) is tidally locked with the helium star, which evolved from the
giant, as the hydrogen envelope is stripped off in common envelope evolution.
The tidal locking is transferred from the helium star to the black hole into
which it falls. Depending on the mass of the donor, the black hole can be spun
up to the angular momentum necessary to power the GRB and Hypernova explosion.
The donor decouples, acting as a passive witness to the explosion which, for
the given angular momentum, then proceeds as in the Woosley Collapsar model.
High mass donors which tend to follow from low metallicity give long GRBs
because their lower energy can be accepted by the central engine.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 23:58:06 GMT"
},
{
"version": "v2",
"created": "Mon, 29 Oct 2007 14:56:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Brown",
"G. E.",
""
],
[
"Lee",
"C. -H.",
""
],
[
"Mendez",
"E. Moreno",
""
]
] |
0707.4009 | Xianglin Ke | X. Ke, B. G. Ueland, D.V. West, M. L. Dahlberg, R. J. Cava, and P.
Schiffer | Spin ice behavior in Dy2Sn2-xSbxO7+x/2 and Dy2NbScO7 | null | Phys. Rev. B 76, 214413 (2007) | 10.1103/PhysRevB.76.214413 | null | cond-mat.str-el cond-mat.mtrl-sci | null | We report the magnetic and thermal properties of Dy2Sn2-xSbxO7+x/2, x = 0,
0.25, and 0.5, and Dy2NbScO7. We find evidence for Ising-like single ion ground
states in the Dy2Sn2-xSbxO7+x/2 materials. These materials possess nearly the
same zero point entropy as the canonical spin ices Ho2Ti2O7 and Dy2Ti2O7,
strongly suggesting that they have spin ice states at low temperatures. We also
observe a somewhat reduced zero point entropy in Dy2NbScO7, which is possibly
associated with the higher level of cation disorder. The ice-like states in
these materials with cation disorder on the B-sites of the pyrochlore lattice
provide new evidence for the robust nature of spin ice behavior in the presence
of disorder.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:30:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ke",
"X.",
""
],
[
"Ueland",
"B. G.",
""
],
[
"West",
"D. V.",
""
],
[
"Dahlberg",
"M. L.",
""
],
[
"Cava",
"R. J.",
""
],
[
"Schiffer",
"P.",
""
]
] |
0707.4010 | Maximiliano Ujevic | Maximiliano Ujevic, Patricio S. Letelier | Stability of general relativistic Miyamoto-Nagai galaxies | 11 pages, 5 figures, accepted for publication in MNRAS | MNRAS 381, 1499-1507 (2007) | 10.1111/j.1365-2966.2007.12242.x | null | gr-qc astro-ph | null | The stability of a recently proposed general relativistic model of galaxies
is studied in some detail. This model is a general relativistic version of the
well known Miyamoto-Nagai model that represents well a thick galactic disk. The
stability of the disk is investigated under a general first order perturbation
keeping the spacetime metric frozen (no gravitational radiation is taken into
account). We find that the stability is associated with the thickness of the
disk. We have that flat galaxies have more not-stable modes than the thick ones
i.e., flat galaxies have a tendency to form more complex structures like rings,
bars and spiral arms.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 20:39:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ujevic",
"Maximiliano",
""
],
[
"Letelier",
"Patricio S.",
""
]
] |
0707.4011 | Jonathan Heckman | Jonathan J. Heckman and Cumrun Vafa | Geometrically Induced Phase Transitions at Large N | 47 pages, 7 figures | JHEP0804:052,2008 | 10.1088/1126-6708/2008/04/052 | null | hep-th | null | Utilizing the large N dual description of a metastable system of branes and
anti-branes wrapping rigid homologous S^2's in a non-compact Calabi-Yau
threefold, we study phase transitions induced by changing the positions of the
S^2's. At leading order in 1/N the effective potential for this system is
computed by the planar limit of an auxiliary matrix model. Beginning at the two
loop correction, the degenerate vacuum energy density of the discrete confining
vacua split, and a potential is generated for the axion. Changing the relative
positions of the S^2's causes discrete jumps in the energetically preferred
confining vacuum and can also obstruct direct brane/anti-brane annihilation
processes. The branes must hop to nearby S^2's before annihilating, thus
significantly increasing the lifetime of the corresponding non-supersymmetric
vacua. We also speculate that misaligned metastable glueball phases may
generate a repulsive inter-brane force which stabilizes the radial mode present
in compact Calabi-Yau threefolds.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 13:51:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Heckman",
"Jonathan J.",
""
],
[
"Vafa",
"Cumrun",
""
]
] |
0707.4012 | Parthapratim Biswas | Parthapratim Biswas, Raymond Atta-Fynn, S. Chakraborty, D.A.Drabold | Real space information from Fluctuation electron microscopy:
Applications to amorphous silicon | 13 pages, 10 figures, invited paper for the workshop on Nanoscale
Order in Amorphous and Partially ordered Solids, Trinity College, Cambridge,
UK | null | 10.1088/0953-8984/19/45/455202 | null | cond-mat.dis-nn cond-mat.mtrl-sci | null | Ideal models of complex materials must satisfy all available information
about the system. Generally, this information consists of experimental data,
information implicit to sophisticated interatomic interactions and potentially
other {\it a priori} information. By jointly imposing first-principles or
tight-binding information in conjunction with experimental data, we have
developed a method: Experimentally Constrained Molecular Relaxation (ECMR) that
uses {\it all} of the information available. We apply the method to model
medium range order in amorphous silicon using Fluctuation Electron microscopy
(FEM) data as experimental information. The paracrystalline model of medium
range order is examined, and a new model based on voids in amorphous silicon is
proposed. Our work suggests that films of amorphous silicon showing medium
range order (in FEM experiments) can be accurately represented by a continuous
random network model with inhomogeneities consisting of ordered grains and
voids dispersed in the network.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:15:41 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Biswas",
"Parthapratim",
""
],
[
"Atta-Fynn",
"Raymond",
""
],
[
"Chakraborty",
"S.",
""
],
[
"Drabold",
"D. A.",
""
]
] |
0707.4013 | Richard Wigmans | N. Akchurin, et al | Contributions of Cherenkov Light to the Signals from Lead Tungstate
Crystals | Preprint submitted to Nucl. Instr. and Meth. on July 13, 2007 | null | 10.1016/j.nima.2007.08.174 | null | physics.ins-det | null | Results are presented of detailed measurements of the signals generated by
high-energy electrons and muons in lead tungstate crystals. A significant
fraction of the light produced in these crystals and detected by
photomultiplier tubes is the result of the \v{C}erenkov mechanism. This is
concluded from the angular dependence of the signals and from their time
structure. Depending on the orientation of the crystals and on the particle
type, \v{C}erenkov light may account for up to 15% of the total signals.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:23:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Akchurin",
"N.",
""
]
] |
0707.4014 | Michael Dennin | M. Lundberg, K. Krishan, N. Xu, C. S. O'Hern, and M. Dennin | Reversible plasticity in amorphous materials | Revised paper | Phys. Rev. E 77, 041505 (2008) | 10.1103/PhysRevE.77.041505 | null | cond-mat.soft cond-mat.mtrl-sci | null | A fundamental assumption in our understanding of material rheology is that
when microscopic deformations are reversible, the material responds elastically
to external loads. Plasticity, i.e. dissipative and irreversible macroscopic
changes in a material, is assumed to be the consequence of irreversible
microscopic events. Here we show direct evidence for reversible plastic events
at the microscopic scale in both experiments and simulations of two-dimensional
foam. In the simulations, we demonstrate a link between reversible plastic
rearrangement events and pathways in the potential energy landscape of the
system. These findings represent a fundamental change in our understanding of
materials--microscopic reversibility does not necessarily imply elasticity.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:25:10 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 15:53:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lundberg",
"M.",
""
],
[
"Krishan",
"K.",
""
],
[
"Xu",
"N.",
""
],
[
"O'Hern",
"C. S.",
""
],
[
"Dennin",
"M.",
""
]
] |
0707.4015 | Maciej Trzetrzelewski | Maciej Trzetrzelewski | Supersymmetry and Lie groups | 12 pages, to appear in Journal of Mathematical Physics | J.Math.Phys.48:083508,2007 | 10.1063/1.2771418 | null | math-ph math.MP | null | We construct all vacuum states of $\mathcal{N}=2$ supersymmetric Yang-Mills
quantum mechanics (for SU(N) group) and discuss their origin from the SU(N)
real cohomology.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:25:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Trzetrzelewski",
"Maciej",
""
]
] |
0707.4016 | Jeff McIntire | Jeff McIntire, Ying Hu and Brian D. Serot (Indiana U.) | Loop Corrections and Naturalness in a Chiral Effective Field Theory | 22 pages, 6 figures | Nucl.Phys.A794:166-186,2007 | 10.1016/j.nuclphysa.2007.08.008 | null | nucl-th | null | The loop expansion is applied to a chiral effective hadronic lagrangian; with
the techniques of Infrared Regularization, it is possible to separate out the
short-range contributions and to write them as local products of fields that
are already present in our lagrangian. (The appropriate field variables must be
re-defined at each order in loops.) The corresponding parameters implicitly
include short-range effects to all orders in the interaction, so these effects
need not be calculated explicitly. The remaining (long-range) contributions
that must be calculated are nonlocal and resemble those in conventional
nuclear-structure calculations. Nonlinear isoscalar scalar $(\sigma)$ and
vector $(\omega)$ meson interactions are included, which incorporate
many-nucleon forces and nucleon substructure. Calculations are carried out at
the two-loop level to illustrate these techniques at finite nuclear densities
and to verify that the coupling parameters remain natural when fitted to the
empirical properties of equilibrium nuclear matter. Contributions from the
$\omega N$ tensor coupling are also discussed.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:30:37 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 19:09:08 GMT"
},
{
"version": "v3",
"created": "Thu, 23 Aug 2007 17:58:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"McIntire",
"Jeff",
"",
"Indiana U."
],
[
"Hu",
"Ying",
"",
"Indiana U."
],
[
"Serot",
"Brian D.",
"",
"Indiana U."
]
] |
0707.4017 | Israel Klich | Oded Kenneth and Israel Klich | Casimir forces in a T operator approach | null | Phys. Rev. B 78, 014103 (2008) | 10.1103/PhysRevB.78.014103 | null | quant-ph cond-mat.stat-mech hep-th math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We explore the scattering approach to Casimir forces. Our main tool is the
description of Casimir energy in terms of transition operators, as presented in
Kenneth and Klich, Phys. Rev. Lett. 97, 160401 (2006). We study the convergence
properties of the formula and how to utilize it, together with scattering data
to compute the force. We illustrate the approach by describing the force
between scatterers in 1d and 3d,, and in particular show how it may be applied
in order to study the interaction between two spherical bodies at all
distances.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:35:49 GMT"
},
{
"version": "v2",
"created": "Sun, 21 Dec 2008 14:00:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kenneth",
"Oded",
""
],
[
"Klich",
"Israel",
""
]
] |
0707.4018 | Michael A. Clark | J. Brannick, R. C. Brower, M. A. Clark, J. C. Osborn, C. Rebbi | Adaptive Multigrid Algorithm for Lattice QCD | 4 pages, 2 figures | Phys.Rev.Lett.100:041601,2008 | 10.1103/PhysRevLett.100.041601 | null | hep-lat | null | We present a new multigrid solver that is suitable for the Dirac operator in
the presence of disordered gauge fields. The key behind the success of the
algorithm is an adaptive projection onto the coarse grids that preserves the
near null space. The resulting algorithm has weak dependence on the gauge
coupling and exhibits very little critical slowing down in the chiral limit.
Results are presented for the Wilson Dirac operator of the 2d U(1) Schwinger
model.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:37:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Brannick",
"J.",
""
],
[
"Brower",
"R. C.",
""
],
[
"Clark",
"M. A.",
""
],
[
"Osborn",
"J. C.",
""
],
[
"Rebbi",
"C.",
""
]
] |
0707.4019 | Richard Wigmans | N. Akchurin, et al | Measurement of the Contribution of Neutrons to Hadron Calorimeter
Signals | Preprint submitted to Nucl. Instr. and Meth. on July 24, 2007 | Nucl.Instrum.Meth.A581:643-650,2007 | 10.1016/j.nima.2007.08.049 | null | physics.ins-det | null | The contributions of neutrons to hadronic signals from the DREAM calorimeter
are measured by analyzing the time structure of these signals. The neutrons,
which mainly originate from the evaporation stage of nuclear breakup in the
hadronic shower development process, contribute through elastic scattering off
protons in the plastic scintillating fibers which provide the $dE/dx$
information in this calorimeter. This contribution is characterized by an
exponential tail in the pulse shape, with a time constant of $\sim 25$ ns. The
relative contribution of neutrons to the signals increases with the distance
from the shower axis. As expected, the neutrons do not contribute to the DREAM
\v{C}erenkov signals.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:37:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Akchurin",
"N.",
""
]
] |
0707.4020 | Randy Kobes | D. Ostapchuk, G. Passante, R. Kobes, G. Kunstatter | Geometric measures of entanglement and the Schmidt decomposition | 7 pages, latex, 1 figure; changed emphasis to Schmidt decomposition | null | null | null | quant-ph | null | In the standard geometric approach to a measure of entanglement of a pure
state, $\sin^2\theta$ is used, where $\theta$ is the angle between the state to
the closest separable state of products of normalized qubit states. We consider
here a generalization of this notion to separable states consisting of products
of unnormalized states of different dimension. In so doing, the entanglement
measure $\sin^2\theta$ is found to have an interpretation as the distance
between the state to the closest separable state. We also find the components
of the closest separable state and its norm have an interpretation in terms of,
respectively, the eigenvectors and eigenvalues of the reduced density matrices
arising in the Schmidt decomposition of the state vector.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:44:34 GMT"
},
{
"version": "v2",
"created": "Sun, 9 Sep 2007 21:16:46 GMT"
}
] | 2007-09-10T00:00:00 | [
[
"Ostapchuk",
"D.",
""
],
[
"Passante",
"G.",
""
],
[
"Kobes",
"R.",
""
],
[
"Kunstatter",
"G.",
""
]
] |
0707.4021 | Richard Wigmans | N. Akchurin, et al | Dual-Readout Calorimetry with Lead Tungstate Crystals | Preprint submitted to Nucl. Instrum. Meth. on July 23, 2007 | Nucl.Instrum.Meth.A584:273-284,2008 | 10.1016/j.nima.2007.09.035 | null | physics.ins-det | null | Results are presented of beam tests in which a small electromagnetic
calorimeter consisting of lead tungstate crystals was exposed to 50 GeV
electrons and pions. This calorimeter was backed up by the DREAM Dual-Readout
calorimeter, which measures the scintillation and \v{C}erenkov light produced
in the shower development, using two different media. The signals from the
crystal calorimeter were analyzed in great detail in an attempt to determine
the contributions from these two types of light to the signals, event by event.
This information makes it possible to eliminate the dominating source of
fluctuations and thus achieve an important improvement in hadronic calorimeter
performance.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 21:53:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Akchurin",
"N.",
""
]
] |
0707.4022 | Hartmut Hafermann | H. Hafermann, S. Brener, A. N. Rubtsov, M. I. Katsnelson and A. I.
Lichtenstein | Cluster Dual Fermion Approach to Nonlocal Correlations | null | JETP Lett. 86, 677-682 (2007) | 10.1134/S0021364007220134 | null | cond-mat.str-el | null | We formulate a general cluster Dual Fermion Approach to nonlocal correlations
in crystals. The scheme allows the treatment of long-range correlations beyond
cluster DMFT and nonlocal effects in realistic calculations of multiorbital
systems. We show that the the simplest approximation exactly corresponds to
free cluster DMFT. We further consider the relation between the two-particle
Green functions in real and dual variables. We apply this approach by
calculating the Green function of the Hubbard model in one dimension starting
from the two-site cluster DMFT solution. The result agrees well with the Green
function obtained from a DMRG calculation.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 22:06:47 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Hafermann",
"H.",
""
],
[
"Brener",
"S.",
""
],
[
"Rubtsov",
"A. N.",
""
],
[
"Katsnelson",
"M. I.",
""
],
[
"Lichtenstein",
"A. I.",
""
]
] |
0707.4023 | Paul J. Wiita | Gopal-Krishna, Samir Dhurde, Pronoy Sircar, Paul J. Wiita | Influence of the jet opening angle on the derived kinematical parameters
of blazar jets having uniform and stratified bulk motion | 8 pages, 4 figures, official version appeared in MNRAS | Mon.Not.Roy.Astron.Soc.377:446-452,2007 | 10.1111/j.1365-2966.2007.11633.x | null | astro-ph | null | We present analytical modelling of conical relativistic jets, in order to
evaluate the role of the jet opening angle on certain key parameters that are
inferred from VLBI radio observations of blazar nuclear jets. The key
parameters evaluated are the orientation angle (i.e., the viewing angle) of the
jet and the apparent speed and Doppler factor of the radio knots on parsec
scales. Quantitative comparisons are made of the influence of the jet opening
angle on the above parameters of the radio knots, as would be estimated for two
widely discussed variants of relativistic nuclear jets, namely, those having
uniform bulk speed and those in which the bulk Lorentz factor of the flow
decreases with distance from the jet axis (a `spine--sheath' flow). Our
analysis shows that for both types of jet velocity distributions the
expectation value of the jet orientation angle at first falls dramatically with
increases in the (central) jet Lorentz factor, but it levels off at a fraction
of the opening angle for extremely relativistic jets. We also find that the
effective values of the apparent speeds and Doppler factors of the knots always
decline substantially with increasing jet opening angle, but that this effect
is strongest for ultra-relativistic jets with uniform bulk speed. We suggest
that the paucity of highly superluminal parsec-scale radio components in TeV
blazars can be understood if their jets are highly relativistic and, being
intrinsically weaker, somewhat less well collimated, in comparison to the jets
in other blazars.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 22:13:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gopal-Krishna",
"",
""
],
[
"Dhurde",
"Samir",
""
],
[
"Sircar",
"Pronoy",
""
],
[
"Wiita",
"Paul J.",
""
]
] |
0707.4024 | Vladimir V Kisil | Vladimir V. Kisil | Erlangen Program at Large--2: Inventing a wheel. The parabolic one | LaTeX paper (14 pages) and software documentation in an appendix (20
pages); two figures (five PS files) | Trans. Inst. Math. of the NAS of Ukraine, v. 7, n. 2, pp. 89--98,
2010 | null | LEEDS-MATH-PURE-2007-07 | math.GM math.RA math.RT | null | We discuss parabolic versions of Euler's identity e^{it}=cos t + i sin t. A
purely algebraic approach based on dual numbers is known to produce a very
trivial relation e^{pt} = 1+pt. Therefore we use a geometric setup of parabolic
rotations to recover the corresponding non-trivial algebraic framework. Our
main tool is Moebius transformations which turn out to be closely related to
induced representations of the group SL(2,R).
Keywords: complex numbers, dual numbers, double numbers, linear algebra,
invariant, computer algebra, GiNaC
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 11:42:15 GMT"
}
] | 2010-11-25T00:00:00 | [
[
"Kisil",
"Vladimir V.",
""
]
] |
0707.4025 | Ashkbiz Danehkar PhD | A. Danehkar | On the Cohomological Derivation of Yang-Mills Theory in the Antifield
Formalism | 19 pages, few typos corrected, final version | JHEP Grav.Cosmol.3:368-387,2017 | 10.4236/jhepgc.2017.32031 | null | physics.gen-ph | http://creativecommons.org/licenses/by/4.0/ | We present a brief review of the cohomological solutions of self-coupling
interactions of the fields in the free Yang-Mills theory. All consistent
interactions among the fields have been obtained using the antifield formalism
through several order BRST deformations of the master equation. It is found
that the coupling deformations halt exclusively at the second order, whereas
higher order deformations are obstructed due to non-local interactions. The
results demonstrate the BRST cohomological derivation of the interacting
Yang-Mills theory.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 23:17:11 GMT"
},
{
"version": "v2",
"created": "Fri, 10 Aug 2007 12:56:42 GMT"
},
{
"version": "v3",
"created": "Mon, 22 Dec 2008 03:17:38 GMT"
},
{
"version": "v4",
"created": "Fri, 2 Jan 2009 14:21:49 GMT"
},
{
"version": "v5",
"created": "Sat, 3 Jan 2009 14:00:12 GMT"
},
{
"version": "v6",
"created": "Mon, 19 Oct 2009 05:52:53 GMT"
},
{
"version": "v7",
"created": "Tue, 2 May 2017 09:27:09 GMT"
},
{
"version": "v8",
"created": "Sat, 24 Jun 2017 17:46:42 GMT"
}
] | 2017-07-20T00:00:00 | [
[
"Danehkar",
"A.",
""
]
] |
0707.4026 | Theodore A. Jacobson | Ted Jacobson | Renormalization and black hole entropy in Loop Quantum Gravity | 8 pages; v2: references added, typos corrected, version to appear in
CQG | Class.Quant.Grav.24:4875-4879,2007 | 10.1088/0264-9381/24/18/N02 | null | gr-qc hep-th | null | Microscopic state counting for a black hole in Loop Quantum Gravity yields a
result proportional to horizon area, and inversely proportional to Newton's
constant and the Immirzi parameter. It is argued here that before this result
can be compared to the Bekenstein-Hawking entropy of a macroscopic black hole,
the scale dependence of both Newton's constant and the area must be accounted
for. The two entropies could then agree for any value of the Immirzi parameter,
if a certain renormalization property holds.
| [
{
"version": "v1",
"created": "Thu, 26 Jul 2007 23:33:10 GMT"
},
{
"version": "v2",
"created": "Sat, 25 Aug 2007 02:11:25 GMT"
}
] | 2010-10-27T00:00:00 | [
[
"Jacobson",
"Ted",
""
]
] |
0707.4027 | Hirotaka Ito | H. Ito, M. Kino, N. Kawakatu, N. Isobe, and S. Yamada | Large Kinetic Power in FRII Radio Jets | 5 pages, accepted for publication in Astrophysics and Space Science | Astrophys.SpaceSci.311:335-339,2007 | 10.1007/s10509-007-9539-z | null | astro-ph | null | We investigate the total kinetic powers (L_{j}) and ages (t_{age}) of
powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C
219) by the detail comparison of the dynamical model of expanding cocoons with
observed ones. It is found that these sources have quite large kinetic powers
with the ratio of L_{j} to the Eddington luminosity (L_{Edd}) resides in $0.02
<L_{j}/L_{Edd} <10$. Reflecting the large kinetic powers, we also find that the
total energy stored in the cocoon (E_{c}) exceed the energy derived from the
minimum energy condition (E_{min}): $2< E_{c}/E_{min} <160$. This implies that
a large amount of kinetic power is carried by invisible components such as
thermal leptons (electron and positron) and/or protons.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 00:00:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ito",
"H.",
""
],
[
"Kino",
"M.",
""
],
[
"Kawakatu",
"N.",
""
],
[
"Isobe",
"N.",
""
],
[
"Yamada",
"S.",
""
]
] |
0707.4028 | Philip Fellman | Philip V. Fellman and Mark Strathern | The Symmetries and Redundancies of Terror: Patterns in the Dark, A study
of Terrorist Network Strategy and Structure | 13 pages, 3 figures. Proceedings of the 2004 annual meeting of the
North American Association for Computation in the Social and Organizational
Sciences | null | null | null | nlin.AO | null | Although much political capital has been made regarding the war on terrorism,
and while appropriations have gotten underway, there has been a dearth of deep
work on counter-terrorism, and despite massive efforts by the federal
government, most cities and states do not have a robust response system. In
fact, most do not yet have a robust audit system with which to evaluate their
vulnerabilities or their responses. At the federal level there remain many
unresolved problems of coordination. One reason for this is the shift of much
of federal spending on war-fighting in Afghanistan and Iraq. While this
approach has drawn deep and lasting criticism, it is, in fact, in accord with
many principles of both military and corporate strategy. In the following paper
we explore several models of terrorist networks and the implications of both
the models and their substantive conclusions for combating terrorism.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 00:07:11 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Fellman",
"Philip V.",
""
],
[
"Strathern",
"Mark",
""
]
] |
0707.4029 | Sergey Sergeev | S. M. Sergeev | Tetrahedron equations and nilpotent subalgebras of U_q(sl_n) | 4 pages | null | 10.1007/s11005-008-0219-x | null | math.QA | null | A relation between q-oscillator R-matrix of the tetrahedron equation and
decompositions of Poinkare-Birkhoff-Witt type bases for nilpotent subalgebras
of U_q(sl_n) is observed.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 00:50:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sergeev",
"S. M.",
""
]
] |
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