Matt's arXiv selection: week ending 9 January 2009

From: Matthew Davis <>
Date: Wed, 11 Mar 2009 07:48:11 +1000

The following message was sent to the matts_arxiv list by Matthew Davis <>

This week saw 15 new preprints and 10 replacements.

Date: Tue, 30 Dec 2008 21:41:23 GMT (2682kb)

Title: Obtaining phase diagram and thermodynamic quantities of bulk systems
   from the densities of trapped gases
Authors: Tin-Lun Ho and Qi Zhou
Categories: cond-mat.supr-con cond-mat.other
Comments: 15pages, 2figures
   At present, many laboratories are performing experiments to simulate
theoretical models of strongly correlated systems using cold atoms in optical
lattices, a program referred to as "Quantum Simulation". It is hoped that these
experiments will shed light on some long standing problems in condensed matter
physics. The goal of Quantum Simulation is to obtain information of homogenous
bulk systems. However, experiments are performed in confining traps. The
non-uniformity of the trapping potential inevitably introduces different phases
in the sample, making it difficult to deduce the properties of a single bulk
phase. So far, there are no algorithms to use the experimental data to map out
phase diagrams and important thermodynamic quantities. Here, we present an
algorithm to achieve this goal. Apart from phase diagram, it also maps out
entropy density, superfluid density of superfluids, and staggered
magnetizations of anti-ferromagnets. Our scheme is exact within local density
\\ ( , 2682kb)
Date: Fri, 2 Jan 2009 13:44:36 GMT (839kb,D)

Title: Exponential localization in one-dimensional quasiperiodic optical
Authors: Michele Modugno
Categories: cond-mat.other
Comments: 13 pages, 6 figures
   We investigate the localization properties of a one-dimensional bichromatic
optical lattice in the tight binding regime, by discussing how exponentially
localized states emerge upon changing the degree of commensurability. We also
review the mapping onto the discrete Aubry-Andre' model, and provide evidences
on how the momentum distribution gets modified in the crossover from extended
to exponentially localized states. This analysis is relevant to the recent
experiment on Anderson localization of a noninteracting Bose-Einstein
condensate in a quasiperiodic optical lattice [G. Roati et al., Nature 453, 895
\\ ( , 839kb)
arXiv:0812.5073 (*cross-listing*)
Date: Fri, 26 Dec 2008 16:22:41 GMT (3209kb)

Title: Bright and dark solitons in Bose-Einstein condensates
Authors: S. Rajendran, P. Muruganandam, M. Lakshmanan
Categories: nlin.PS cond-mat.other nlin.SI
Comments: 30 pages, 31 figures, 3 tables
   We investigate the exact bright and dark solitary wave solutions of an one
dimensional Bose-Einstein condensate with a time varying scattering length and
gain or loss confined in an expulsive parabolic potential. We show that the
modified Gross-Pitaevskii (GP) equation with time varying control parameters is
transformable to the standard nonlinear Schr\"odinger (NLS) equation. By making
use of both the bright and dark soliton solutions of the standard NLS equation,
we bring out various dynamical features associated with Bose-Einstein
condensates such as the collapse and revival of condensate, formation of two
soliton bound state, oscillating solitons, snake-like solitons, soliton growth
and decay for time independent harmonic potentials. We also point out the
existence of such soliton solutions in the experimental range of parameters for
various forms of atomic scattering length and gain/loss terms. In addition we
discuss the nature of various soliton solutions for time dependent potentials
such as oscillatory soliton solution, the phenomena of collapse and revival of
two-soliton like bound state formation of the condensate for doubly periodic
modulation potential and bright and dark solitons for step-wise modulated
\\ ( , 3209kb)
Date: Fri, 2 Jan 2009 20:11:31 GMT (57kb)

Title: Electric dipoles at ultralow temperatures
Authors: John L. Bohn
Categories: physics.atom-ph
   We briefly introduce the formalism for describing dipolar molecules in an
ultracold gaseous environment. This treatment includes the quantum mechanical
states of the dipoles, the electric fields they produce, and their interactions
with one another.
\\ ( , 57kb)
Date: Sun, 4 Jan 2009 02:31:54 GMT (14kb)

Title: Induced P-wave superfluidity within full energy-momentum dependent
   Eliashberg approximation in asymmetric dilute Fermi gases
Authors: Aurel Bulgac and Sukjin Yoon
Categories: cond-mat.stat-mech cond-mat.supr-con
Comments: 4 pages, 1 figure
   We consider a very asymmetric system of Fermions with an interaction
characterized by a positive scattering length only. The minority atoms pair and
form a BEC of dimers, while the surplus fermions interact only indirectly
through the exchange of Bogoliubov sound modes. This interaction has a finite
range, the retardation effects are significant and the surplus fermions will
form a P-wave superfluid. We compute the P-wave pairing gap in the BCS and
Eliashberg with only energy dependence approximations, and demonstrate their
inadequacy in comparison with a full treatment of the momentum and energy
dependence of the induced interaction. The pairing gap computed with a full
momentum and energy dependence is significantly larger in magnitude and that
makes it more likely that this new exotic paired phase could be put in evidence
in atomic trap experiments.
\\ ( , 14kb)
Date: Mon, 5 Jan 2009 05:05:13 GMT (153kb)

Title: Numerical study of the hard-core Bose-Hubbard Model on an Infinite
   Square Lattice
Authors: Jacob Jordan, Roman Orus, Guifre Vidal
Categories: cond-mat.str-el
Comments: 8 pages, 6 figures
   We present a study of the hard-core Bose-Hubbard model at zero temperature on
an infinite square lattice using the infinite Projected Entangled Pair State
algorithm [Jordan et al., Phys. Rev. Lett. 101, 250602 (2008)]. Throughout the
whole phase diagram our values for the ground state energy, particle density
and condensate fraction accurately reproduce those previously obtained by other
methods. We also explore ground state entanglement, compute two-point
correlators and conduct a fidelity-based analysis of the phase diagram.
Furthermore, for illustrative purposes we simulate the response of the system
when a perturbation is suddenly added to the Hamiltonian.
\\ ( , 153kb)
Date: Tue, 6 Jan 2009 06:33:07 GMT (629kb)

Title: Quadrupole Oscillations in Bose-Fermi Mixtures of Ultracold Atomic Gases
   made of Yb atoms in the Time-Dependent Gross-Pitaevskii and Vlasov equations
Authors: Tomoyuki Maruyama and Hiroyuki Yabu
Categories: cond-mat.other physics.atom-ph
   We study quadrupole collective oscillations in the bose-fermi mixtures of
ultracold atomic gases of Yb isotopes, which are realized by Kyoto group. Three
kinds of combinations are chosen, Yb170-Yb171, Yb170-Yb173 and Yb174-Yb173,
where boson-fermion interactions are weakly repulsive, strongly attractive and
strongly repulsive respectively. Collective oscillations in these mixtures are
calculated in a dynamical time-evolution approach formulated with the
time-dependent Gross-Pitaevskii and the Vlasov equations. The boson
oscillations are shown to have one collective mode, and the fermions are shown
to have the boson-forced and two intrinsic modes, which correspond to the
inside- and outside-fermion oscillations for the boson-distributed regions. In
the case of the weak boson-fermion interactions, the dynamical calculations are
shown to be consistent with the results obtained in the small amplitude
approximations as the random phase approximation in early stage of oscillation,
but, in later stage, these two approaches are shown to give the different
results. Also, in the case of the strong boson-fermion interactions,
discrepancies appear in early stage of oscillation. We also analyze these
differences in two approaches, and show that they originated in the change of
the fermion distributions through oscillation.
\\ ( , 629kb)
Date: Tue, 6 Jan 2009 12:02:22 GMT (153kb)

Title: Cold Bosons in Optical Lattices
Authors: V. I. Yukalov
Categories: cond-mat.stat-mech cond-mat.mes-hall
Comments: Latex file, 211 pages, 3 figures
Journal-ref: Laser Phys. 19 (2009) 1-110
   Basic properties of cold Bose atoms in optical lattices are reviewed. The
main principles of correct self-consistent description of arbitrary systems
with Bose-Einstein condensate are formulated. Theoretical methods for
describing regular periodic lattices are presented. A special attention is paid
to the discussion of Bose-atom properties in the frame of the boson Hubbard
model. Optical lattices with arbitrary strong disorder, induced by random
potentials, are treated. Possible applications of cold atoms in optical
lattices are discussed, with an emphasis of their usefulness for quantum
information processing and quantum computing. An important feature of the
present review article, distinguishing it from other review works, is that
theoretical fundamentals here are not just mentioned in brief, but are
thoroughly explained. This makes it easy for the reader to follow the principal
points without the immediate necessity of resorting to numerous publications in
the field.
\\ ( , 153kb)
arXiv:0901.0545 (*cross-listing*)
Date: Mon, 5 Jan 2009 20:58:08 GMT (299kb)

Title: Coordinate-Space Hartree-Fock-Bogoliubov Description of Superfluid Fermi
Authors: J.C. Pei, W. Nazarewicz, M. Stoitsov
Categories: nucl-th cond-mat.supr-con
Comments: 4 pages, 2 figures, ENAM 2008 conference proceedings (EPJA)
   Properties of strongly interacting, two-component finite Fermi systems are
discussed within the recently developed coordinate-space
Hartree-Fock-Bogoliubov (HFB) code {\hfbax}. Two illustrative examples are
presented: (i) weakly bound deformed Mg isotopes, and (ii) spin-polarized
atomic condensates in a strongly deformed harmonic trap.
\\ ( , 299kb)
Date: Tue, 6 Jan 2009 19:06:03 GMT (222kb)

Title: Independent Control of Scattering Lengths in Multicomponent Quantum
Authors: Peng Zhang, Pascal Naidon and Masahito Ueda
Categories: physics.atom-ph
Comments: 4pages, 3figures
   We develop a method of simultaneous and independent control of different
scattering lengths in ultracold multicomponent atomic gases such as $^{\rm
40}$K, $^{\rm 6}$Li and $^{\rm 40}$K-$^{\rm 6}$Li mixtures. Our method can be
used to engineer multi-component quantum phases and Efimov trimer states.
\\ ( , 222kb)
Date: Wed, 7 Jan 2009 12:17:59 GMT (5kb)

Title: The relevance of random choice in tests of Bell inequalities with atomic
Authors: Emilio Santos
Categories: quant-ph
   It is pointed out that a loophole exists in experimental tests of Bell
inequality using atomic qubits, due to possible errors in the rotation angles
of the atomic states. A sufficient condition is derived for closing the
\\ ( , 5kb)
Date: Wed, 7 Jan 2009 15:02:51 GMT (203kb,D)

Title: Efficient routing of single photons by one atom and a microtoroidal
Authors: Takao Aoki, A. S. Parkins, D. J. Alton, C. A. Regal, Barak Dayan, E.
   Ostby, K. J. Vahala, and H. J. Kimble
Categories: quant-ph
   Single photons from a coherent input are efficiently redirected to a separate
output by way of a fiber-coupled microtoroidal cavity interacting with
individual Cesium atoms. By operating in an overcoupled regime for the
input-output to a tapered fiber, our system functions as a quantum router with
high efficiency for photon sorting. Single photons are reflected and excess
photons transmitted, as confirmed by observations of photon antibunching
(bunching) for the reflected (transmitted) light. Our photon router is robust
against large variations of atomic position and input power, with the observed
photon antibunching persisting for intracavity photon number 0.03 \lesssim n
\lesssim 0.7.
\\ ( , 203kb)
Date: Wed, 7 Jan 2009 15:10:04 GMT (751kb,D)

Title: Entanglement and nonlocality of a single relativistic particle
Authors: Jacob Dunningham and Vlatko Vedral
Categories: quant-ph
Comments: 4 pages
   Recent work has argued that the concepts of entanglement and nonlocality must
be taken seriously even in systems consisting of only a single particle. These
treatments, however, are nonrelativistic and, if single particle entanglement
is fundamental, it should also persist in a relativistic description. Here we
consider a spin-1/2 particle in a superposition of two different velocities as
viewed by an observer in a different relativistically-boosted inertial frame.
We show that the entanglement survives right up to the speed of light and that
the boosted observer would see single-particle violations of Bell's inequality.
We also discuss how quantum gates could be implemented in this way and the
possible implications for quantum information processing.
\\ ( , 751kb)
Date: Wed, 7 Jan 2009 22:07:05 GMT (969kb)

Title: Collapses and revivals of stored orbital angular momentum of light in a
   cold atomic ensemble
Authors: D. Moretti, D. Felinto, and J. W. R. Tabosa
Categories: quant-ph
Comments: Submitted to Physical Review A
   We report on the storage of orbital angular momentum of light in a cold
ensemble of cesium atoms. We employ Bragg diffraction to retrieve the stored
optical information impressed into the atomic coherence by the incident light
fields. The stored information can be manipulated by an applied magnetic field
and we were able to observe collapses and revivals due to the rotation of the
stored atomic Zeeman coherence for times longer than 15 $\mu s$.
\\ ( , 969kb)
Date: Thu, 8 Jan 2009 19:51:49 GMT (76kb,D)

Title: Grand-mother clocks and quiet lasers
Authors: Jacques Arnaud (IES), Laurent Chusseau (IES), Fabrice Philippe (LIRMM)
Categories: quant-ph
Comments: 7 pages
   Galileo noted in the 16th century that the period of oscillation of a
pendulum is almost independent of the amplitude. However, such a pendulum is
damped by air friction. The latter may be viewed as resulting from air
molecules getting in contact with the pendulum. It follows that air friction,
not only damps the oscillation, but also introduces randomness. In the
so-called ``grand-mother'' clock, discovered by Huygens in the 18th century,
damping is compensated for, on the average, by an escapement mechanism driven
by a falling weight. The purpose of this paper is to show that such a clock is,
in its idealized form, a quiet oscillator. By ``quiet'' we mean that in spite
of the randomness introduced by damping, the dissipated power (viewed as the
oscillator output) does not fluctuate slowly. Comparison is made with quiet
laser oscillators discovered theoretically in 1984. Because the input power
does not fluctuate in both the mechanical oscillator and the quiet laser
oscillator, the output power does not fluctuate at small Fourier frequencies,
irrespectively of the detailed mechanisms involved.
\\ ( , 76kb)

The replacements:

replaced with revised version Wed, 31 Dec 2008 22:18:02 GMT (76kb)

Title: Coherent Collective Excitations in a Superfluid: Spontaneously Broken
   Symmetries and Fluctuations-Dissipation
Authors: S.J. Han
Categories: cond-mat.other
Comments: 84 pages, 1 figure
\\ ( , 76kb)
replaced with revised version Wed, 31 Dec 2008 10:38:57 GMT (340kb)

Title: Optimal geometry for efficient loading of an optical dipole trap
Authors: Andrzej Szczepkowicz, Leszek Krzemien, Adam Wojciechowski, Krzysztof
   Brzozowski, Michael Kruger, Michal Zawada, Marcin Witkowski, Jerzy
   Zachorowski, Wojciech Gawlik
Categories: physics.atom-ph
Comments: 6 figures. Phys. Rev. A, in press
\\ ( , 340kb)
replaced with revised version Wed, 31 Dec 2008 19:50:03 GMT (32kb)

Title: Comment on "Using Three-Body Recombination to Extract Electron
   Temperatures of Ultracold Plasmas"
Authors: Yurii V. Dumin (Max Planck Institute for the Physics of Complex
   Systems, Dresden, Germany)
Categories: physics.atom-ph physics.plasm-ph
Comments: Main article: Dumin.tex (REVTeX4, 1 page); supplementary material:
   figures_Dumin.pdf (Adobe PDF, 1 page, should be extracted from the submission
   package separately). Ver.2: Supplementary material added, minor stylistic
   changes in the main article. Submitted to Phys. Rev. Lett. (2008)
\\ ( , 32kb)
replaced with revised version Mon, 5 Jan 2009 16:10:24 GMT (273kb)

Title: Sign-Alternating Interaction Mediated by Strongly-Correlated Lattice
Authors: \c{S}.G. S\"oyler, B. Capogrosso-Sansone, N.V. Prokof'ev, B.V.
Categories: cond-mat.other cond-mat.stat-mech
Comments: 4 pages, 2 figures. Title, abstract and introductory part are
   rewritten. Some technical details are removed
\\ ( , 273kb)
replaced with revised version Tue, 6 Jan 2009 05:39:56 GMT (805kb,D)

Title: Vortex waves in trapped Bose-Einstein condensates
Authors: T. P. Simula, T. Mizushima, and K. Machida
Categories: cond-mat.other
Comments: minor changes, 7 pages, 7 figures
Journal-ref: Phys. Rev. A 78, 053604 (2008)
DOI: 10.1103/PhysRevA.78.053604
\\ ( , 805kb)
replaced with revised version Wed, 7 Jan 2009 13:02:35 GMT (33kb)

Title: Density Matrix Renormalization Group in the Heisenberg Picture
Authors: Michael J. Hartmann, Javier Prior, Stephen R. Clark and Martin B.
Categories: cond-mat.str-el cond-mat.other quant-ph
Comments: version to appear in PRL, acronyms in title and abstract expanded,
   new improved numerical examples
\\ ( , 33kb)
arXiv:0806.2125 (*cross-listing*)
replaced with revised version Tue, 6 Jan 2009 23:06:37 GMT (1377kb)

Title: An Atomic Gravitational Wave Interferometric Sensor (AGIS)
Authors: Savas Dimopoulos, Peter W. Graham, Jason M. Hogan, Mark A. Kasevich,
   Surjeet Rajendran
Categories: gr-qc astro-ph hep-ph hep-th physics.atom-ph
Comments: 41 pages, 19 figures; v2: revised version as in Phys. Rev. D
Journal-ref: Phys.Rev.D78:122002,2008
DOI: 10.1103/PhysRevD.78.122002
\\ ( , 1377kb)
replaced with revised version Thu, 8 Jan 2009 15:48:15 GMT (844kb,D)

Title: Optimizing number squeezing when splitting a mesoscopic condensate
Authors: Julian Grond, Joerg Schmiedmayer, Ulrich Hohenester
Categories: cond-mat.other
Comments: 4 pages, v2: revised version. To appear in Phys. Rev. A Rapid
\\ ( , 844kb)
replaced with revised version Thu, 8 Jan 2009 06:52:15 GMT (248kb)

Title: Relationship between spin squeezing and single-particle coherence in
   two-component Bose-Einstein condensates with Josephson coupling
Authors: G. R. Jin and C. K. Law
Categories: cond-mat.other physics.atom-ph quant-ph
Comments: 4 figures, revtex4, new refs. are added
Journal-ref: Phys. Rev. A 78, 063620 (2008)
DOI: 10.1103/PhysRevA.78.063620
\\ ( , 248kb)
replaced with revised version Thu, 8 Jan 2009 11:47:56 GMT (673kb)

Title: Coupled two-component atomic gas in an optical lattice
Authors: Jonas Larson, Jani-Petri Martikainen
Categories: cond-mat.other quant-ph
Comments: 10 pages, 7 figures
Journal-ref: Phys. Rev. A, 78, 063618 (2008)
DOI: 10.1103/PhysRevA.78.063618
\\ ( , 673kb)

Till next time,

Dr M. J. Davis,                      Associate Professor in Physics
School of Mathematics and Physics,   ph  : +61 7 334 69824
The University of Queensland,        fax : +61 7 336 51242
Brisbane, QLD 4072,        
Matt's arXiv selection: weekly summary of cold-atom papers from
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Received on Fri May 01 2009 - 15:51:03 EST

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