# Matt's arXiv selection, Tuesday 10th October 2006.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Tue, 10 Oct 2006 10:36:57 +1000 (EST)

The following message was sent to the matts_arxiv list by Matthew Davis <mdavis_at_physics.uq.edu.au>

Not so late this time... 27 new preprints last week.

New preprints:

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Paper: cond-mat/0609748
Date: Thu, 28 Sep 2006 23:56:57 GMT (42kb)

Title: Quantum Noise Analysis of Spin Systems Realized with Cold Atoms
Authors: R. W. Cherng, Eugene Demler
Comments: 18 pages, 4 figures
Subj-class: Strongly Correlated Electrons; Statistical Mechanics
\\
We consider the use of quantum noise to characterize many-body states of spin
systems realized with ultracold atomic systems. These systems offer a wealth of
experimental techniques for realizing strongly interacting many-body states in
a regime with a large but not macroscropic number of atoms where fluctuations
of an observable such as the magnetization are discernable compared to the mean
value. The full distribution function is experimentally relevant and encodes
high order correlation functions that may distinguish various many-body states.
We apply quantum noise analysis to the Ising model in a transverse field and
find a distinctive even versus odd splitting in the distribution function for
the transverse magnetization that distinguishes between the ordered, critical,
and disordered phases. We also discuss experimental issues relevant for
applying quantum noise analysis for general spin systems and the specific
results obtained for the Ising model.
\\ ( http://arXiv.org/abs/cond-mat/0609748 , 42kb)
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Paper: cond-mat/0609761
Date: Fri, 29 Sep 2006 11:10:49 GMT (322kb)

Title: The atomic Bose gas in Flatland
Authors: Zoran Hadzibabic (LKB - Lhomond), Peter Kr\"{u}ger (LKB - Lhomond),
Marc Cheneau (LKB - Lhomond), Baptiste Battelier (LKB - Lhomond), Jean B.
Dalibard (LKB - Lhomond)
Comments: To appear in "ATOMIC PHYSICS 20" Proceedings of the XX International
Conference on Atomic Physics (ICAP)
Proxy: ccsd ccsd-00102179
Subj-class: Other
\\
We describe a recent experiment performed with rubidium atoms ($^{87}$Rb),
aiming at studying the coherence properties of a two-dimensional gas of bosonic
particles at low temperature. We have observed in particular a
Berezinskii--Kosterlitz--Thouless (BKT) type crossover in the system, using a
matter wave heterodyning technique. At low temperatures, the gas is
quasi-coherent on the length scale set by the system size. As the temperature
is increased, the loss of long-range coherence coincides with the onset of the
proliferation of free vortices, in agreement with the microscopic BKT theory.
\\ ( http://arXiv.org/abs/cond-mat/0609761 , 322kb)
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Paper: cond-mat/0609774
Date: Fri, 29 Sep 2006 16:15:05 GMT (598kb)

Title: Analysis of Localization Phenomena in Weakly Interacting Disordered
Lattice Gases
Authors: T. Schulte, S. Drenkelforth, J. Kruse, R. Tiemeyer, K. Sacha, J.
Zakrzewski, M. Lewenstein, W. Ertmer, and J.J. Arlt
Comments: 9 pages, 13 figures
Subj-class: Disordered Systems and Neural Networks
\\
Disorder plays a crucial role in many systems particularly in solid state
physics. However, the disorder in a particular system can usually not be chosen
or controlled. We show that the unique control available for ultracold atomic
gases may be used for the production and observation of disordered quantum
degenerate gases. A detailed analysis of localization effects for two possible
realizations of a disordered potential is presented. In a theoretical analysis
clear localization effects are observed when a superlattice is used to provide
a quasiperiodic disorder. The effects of localization are analyzed by
investigating the superfluid fraction and the localization length within the
system. The theoretical analysis in this paper paves a clear path for the
future observation of Anderson-like localization in disordered quantum gases.
\\ ( http://arXiv.org/abs/cond-mat/0609774 , 598kb)
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Paper: quant-ph/0609225
Date: Fri, 29 Sep 2006 06:49:47 GMT (15kb)

Title: Generating quadrature squeezing in an atom laser through
self-interaction
Authors: Mattias T. Johnsson and Simon A. Haine
Comments: 4 pages, 3 figures
\\
We describe a scheme for creating a quadrature-squeezed atom laser that does
not require squeezed light as an input. The beam becomes squeezed due to
nonlinear interactions between the atoms in the beam in an analogue to optical
Kerr squeezing. We develop an analytic model of the process which we compare to
a detailed stochastic simulation of the system using phase space methods.
Finally we show that significant squeezing can be obtained in an experimentally
realistic system and suggest ways of increasing the tunability of the
squeezing.
\\ ( http://arXiv.org/abs/quant-ph/0609225 , 15kb)
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Paper: quant-ph/0609236
Date: Fri, 29 Sep 2006 17:37:07 GMT (274kb)

Title: A fast and robust approach to long-distance quantum communication with
atomic ensembles
Authors: L. Jiang, J. M. Taylor, M. D. Lukin
Comments: 6 pages, 4 figures
\\
Quantum communication holds promise for cryptography, teleportation of
arbitrary quantum states, and violation of Bell's inequalities over long
distances. While commercial implementation of simple quantum communication
protocols are well established, attenuation in optical fibers makes longer
distances exponentially challenging. Quantum repeaters overcome the time
overhead associated with fiber attenuation by using a quantum memory and local
quantum operations. A simple implementation uses atomic ensembles and linear
optics (Duan, Lukin, Cirac, Zoller, Nature 414, 413 (2001)). Motivated by
experimental progress, here we develop an efficient scheme compatible with the
active purification of arbitrary errors. Using similar resources as the DLCZ
approach, our approach intrinsically purifies leakage out of the logical
subspace and all errors within the logical subspace, leading to greatly
improved performance in the presence of experimental inefficiencies. We find
that about one, 1280 km-distant entangled pair per minute could be realized
with a fidelity sufficient to violate Bell's inequality.
\\ ( http://arXiv.org/abs/quant-ph/0609236 , 274kb)
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Paper: cond-mat/0610006
Date: Sat, 30 Sep 2006 06:47:52 GMT (735kb)

Title: Finite Temperature Effects in Ultracold Fermi Gases
Authors: K. Levin and Qijin Chen
Comments: Lecture given at the International School of Physics "Enrico Fermi"
-- the 2006 Varenna Summer School on "Ultracold Fermi Gases", 27 pages, 17
figures
Subj-class: Strongly Correlated Electrons; Superconductivity
\\
This article is written as a Lecture given in the 2006 Varenna Summer School
on "Ultracold Fermi Gases". Here we present a review of BCS--Bose Einstein
condensation (BEC) crossover theory with emphasis on finite temperature
effects. We discuss the role of temperature $T$ as it enters a theoretical
formalism which is based on the standard BCS-Leggett ground state. We also
discuss the role of temperature in the context of experiments ranging from
thermometric issues to signatures of superfluidity. Particularly important to
this discussion is the novel normal state associated with the crossover regime,
intermediate between BCS and BEC. The experimental evidence for this unusual
normal state (associated with pre-formed pairs) and its counterpart below $T_c$
(associated with non-condensed pairs) is presented in the context of different
experiments. We end with a discussion of finite temperature effects in spin
polarized superfluids, where $T$ is found to play a crucial role in both theory
and experiment.
\\ ( http://arXiv.org/abs/cond-mat/0610006 , 735kb)
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Paper: cond-mat/0610011
Date: Sun, 1 Oct 2006 00:06:11 GMT (159kb)

Title: BEC-BCS Crossover in the Epsilon Expansion
Authors: Jiunn-Wei Chen and Eiji Nakano
Comments: 9 pages, 3 figures
Subj-class: Other
\\
The epsilon expansion (expansion around four spacial dimensions) developed by
Nishida and Son for a cold fermi gas with infinite scattering length is
extended to finite scattering length to study the BEC-BCS crossover. A
resummation of higher order logarithms and a suitable extension of fermion
coupling in d-dimensions are developed in order to apply the theory in the BCS
regime. The ratio between the chemical potential and the Fermi energy, mu/eF,
is computed to next-to-leading order in the epsilon expansion as a function of
eta=1/(a kF), where a is the scattering length and kF is the Fermi momentum in
a non-interacting system. Near the unitarity limit eta->0, we found
mu/eF=0.475-0.707 eta-0.5 eta^2. Near the BEC limit eta->infinity,
mu/eF=0.062/eta - eta^2, while near the BCS limit eta->-infinity,
mu/eF=1+0.707/eta. Overall good agreement with Quantum Monte Carlo results is
found.
\\ ( http://arXiv.org/abs/cond-mat/0610011 , 159kb)
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Paper: cond-mat/0610014
Date: Sat, 30 Sep 2006 13:30:08 GMT (567kb)

Title: Driven Macroscopic Quantum Tunneling of Ultracold Atoms in Engineered
Optical Lattices
Authors: Ramaz Khomeriki, Stefano Ruffo, Sandro Wimberger
Subj-class: Mesoscopic Systems and Quantum Hall Effect; Superconductivity
\\
Coherent macroscopic tunneling of a Bose-Einstein condensate between two
parts of an optical lattice separated by an energy barrier is theoretically
investigated. We show that by a pulsewise change of the barrier height, it is
possible to switch between tunneling regime and a self-trapped state of the
condensate. This property of the system is explained by effectively reducing
the dynamics to the nonlinear problem of a particle moving in a double square
well potential. The analysis is made for both attractive and repulsive
interatomic forces, and it highlights the experimental relevance of our
findings.
\\ ( http://arXiv.org/abs/cond-mat/0610014 , 567kb)
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Paper: cond-mat/0610016
Date: Sat, 30 Sep 2006 23:40:42 GMT (13kb)

Title: Ground and excited states of spinor Fermi gases in tight waveguides and
the Lieb-Liniger-Heisenberg model
Authors: M. D. Girardeau
Comments: 4 pages, 2 figures, revtex4. To be submitted to Phys. Rev. Lett
Subj-class: Soft Condensed Matter
\\
The ground and excited states of a one-dimensional (1D) spin-1/2 Fermi gas
(SFG) with both attractive zero-range odd-wave interactions and repulsive
zero-range even-wave interactions are mapped exactly to a 1D
Lieb-Liniger-Heisenberg (LLH) model with delta-function repulsions depending on
isotropic Heisenberg spin-spin interactions, such that the complete SFG and LLH
energy spectra are identical. The ground state in the ferromagnetic phase is
given exactly by the Lieb-Liniger (LL) Bethe ansatz, and that in the
antiferromagnetic phase by a variational method combining Bethe ansatz
solutions of the LL and 1D Heisenberg models. There are excitation branches
corresponding to LL type I and II phonons and spin waves, the latter behaving
quadratically for small wave number in the ferromagnetic phase and linearly in
the antiferromagnetic phase.
\\ ( http://arXiv.org/abs/cond-mat/0610016 , 13kb)
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Paper: cond-mat/0610024
Date: Sun, 1 Oct 2006 19:16:31 GMT (28kb)

Title: Entanglement from the Dynamics of an Ideal Bose Gas in a Lattice
Authors: Sougato Bose
Comments: 4 pages, 3 figures
Subj-class: Other
\\
We show how the remotest sites of a finite lattice can be entangled, with the
amount of entanglement exceeding that of a singlet, solely through the dynamics
of an ideal Bose gas in a special initial state in the lattice. When additional
occupation number measurements are made on the intermediate lattice sites, then
the amount of entanglement and the length of the lattice separating the
entangled sites can be significantly enhanced. The entanglement generated by
this dynamical procedure is found to be higher than that for the ground state
of an ideal Bose gas in the same lattice. A second dynamical evolution is shown
to verify the existence of these entangled states, as well entangle qubits
belonging to well separated quantum registers.
\\ ( http://arXiv.org/abs/cond-mat/0610024 , 28kb)
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Paper: cond-mat/0610047
Date: Mon, 2 Oct 2006 18:05:59 GMT (693kb)

Title: A ring accelerator for matter-wave solitons
Authors: Alicia V. Carpentier and Humberto Michinel
Comments: 4 pages, 6 figures
Subj-class: Soft Condensed Matter
\\
We describe a new technique to accelerate and control a confined cloud of
ultracold neutral atoms. In our configuration, a Bose-Einstein Condensate
trapped in a ring is accelerated by using an amplitude-modulated optical
potential. The spreading of the atomic cloud is avoided by an adequate tuning
of the scattering length. We also discuss other variations that offer new
possibilities of robust control of atomic solitons. Our numerical results show
that this cold matter accelerator is easily accessible in the frame of current
experiments.
\\ ( http://arXiv.org/abs/cond-mat/0610047 , 693kb)
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Paper: quant-ph/0610008
Date: Sun, 1 Oct 2006 19:47:06 GMT (9kb)

Title: Entanglement of Josephson junctions revisited
Authors: Robert Alicki
Comments: 6 pages
\\
The recent experimental evidence for entangled states of two Josephson
junction (JJ) qubits seems to support the picture of JJ as a "macroscopic
quantum system". On the other hand the interpretation of experimental data
strongly depends on the assumed theoretical model. Namely, the qubit states are
supposed to be spanned by the orthogonal quantum states of a certain
well-separated subsystem. We analyse the possible states of JJ for three models
: two-mode Bose-Hubbard model, its large $N$ aproximation called quantum-phase
model, and the many-body description within the mean-field approximation
(Gross-Pitaevski equation). While the first two models support the picture of
JJ being a quantum subsystem of a single degree of freedom, the last approach
yields the structure of accessible quantum states which cannot correspond to a
qubit. The phenomenology of the mean-field model is briefly discussed and, in
particular, the absence of observable entanglement for two coupled JJ's is
shown. As the many-body mean-field theory seems to be more fundamental and
better suited for the description of critical phenomena than the others, the
standard interpretation of the JJ experiments becomes questionable.
\\ ( http://arXiv.org/abs/quant-ph/0610008 , 9kb)
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Paper: cond-mat/0610053
Date: Tue, 3 Oct 2006 00:38:50 GMT (986kb)

Title: Transmission and Reflection of Bose-Einstein Condensates Incident on a
Gaussian Potential Barrier
Authors: A.M. Martin, R.G. Scott, T.M. Fromhold
Comments: 9 pages, 9 figures
Subj-class: Other
\\
We investigate how Bose-Einstein condensates, whose initial state is either
irrotational or contains a single vortex, scatter off a one-dimensional
Gaussian potential barrier. We find that for low atom densities the vortex
structure within the condensate is maintained during scattering, whereas at
medium and high densities, multiple additional vortices can be created by the
scattering process, resulting in complex dynamics and disruption of the atom
cloud. This disruption originates from two different mechanisms associated
respectively with the initial rotation of the atom cloud and the interference
between the incident and reflected matter waves. We investigate how the
reflection probability depends on the vorticity of the initial state and on the
incident velocity of the Bose-Einstein condensate. To interpret our results, we
derive a general analytical expression for the reflection coefficient of a
rotating Bose-Einstein condensate that scatters off a spatially-varying
one-dimensional potential.
\\ ( http://arXiv.org/abs/cond-mat/0610053 , 987kb)
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Paper: cond-mat/0610071
Date: Tue, 3 Oct 2006 13:19:25 GMT (257kb)

Title: The ground states of spin-3 Bose-Einstein condensates for conserved
magnetization
Authors: Harri M\"akel\"a, Kalle-Antti Suominen
Comments: 7 pages, 3 figures
Subj-class: Other
\\
We calculate the ground states and ground state phase diagrams of
Bose-Einstein condensates of spin-3 atoms under the assumption of conserved
magnetization. We especially concentrate on the ground states of a chromium
condensate. In chromium the magnetic dipole-dipole interaction enables
magnetization changing collisions, but in a strong magnetic field these are
suppressed. In the calculation of the phase diagrams we neglect the
contribution from the dipole-dipole interaction, but discuss its effects at the
end of the paper. We show that the ground state of a chromium condensate does
not seem to depend on whether or not the dipole-dipole interaction is taken
into attention.
\\ ( http://arXiv.org/abs/cond-mat/0610071 , 257kb)
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Paper: cond-mat/0610072
Date: Tue, 3 Oct 2006 13:17:28 GMT (57kb)

Title: Construction of a giant vortex state in a trapped Fermi system
Authors: Emil Lundh
Comments: 12 pages, 14 figure files
Subj-class: Other
\\
A superfluid atomic Fermi system may support a giant vortex if the trapping
potential is anharmonic. In such a potential, the single-particle spectrum has
a positive curvature as a function of angular momentum. A tractable model is
put up in which the lowest and next lowest Landau levels are occupied.
Different parameter regimes are identified and characterized. Due to the
dependence of the interaction on angular momentum quantum number, the Cooper
pairing is at its strongest not only close to the Fermi level, but also close
to the energy minimum. It is shown that the gas is superfluid in the interior
of the toroidal density distribution and normal in the outer regions.
Furthermore, the pairing may give rise to a localized density depression in
configuration space.
\\ ( http://arXiv.org/abs/cond-mat/0610072 , 57kb)
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Paper: cond-mat/0610079
Date: Tue, 3 Oct 2006 15:26:04 GMT (180kb)

Title: Equilibrium phase diagrams on degenerate Fermi gas with Feshbach
resonance
Authors: S. Watabe, T. Nikuni, N. Nygaard, J. E. Williams, and C. W. Clark
Comments: 16 pages, 8 figures
Subj-class: Other
\\
We determine the adiabatic phase diagram for a resonantly-coupled system of
Fermi atoms and Bose molecules confined in the harmonic trap by using the local
density approximation. The adiabatic phase diagram shows the fermionic
condensate fraction composed of condensed molecules and Cooper pair atoms. The
key idea of our work is conservation of entropy through the adiabatic process,
extending the study of Williams et al. [Williams et al., New J. Phys. 6, 123
(2004)] for an ideal gas mixture to include the resonant interaction in a
mean-field theory. We also calculate the molecular conversion efficiency as a
function of initial temperature. Our work helps to understand recent
experiments on the BCS-BEC crossover, in terms of the initial temperature
measured before a sweep of the magnetic field.
\\ ( http://arXiv.org/abs/cond-mat/0610079 , 180kb)
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Paper: cond-mat/0610082
Date: Tue, 3 Oct 2006 15:37:21 GMT (35kb)

Title: Matter wave solitons at finite temperatures
Authors: B. Jackson, C. F. Barenghi, and N. P. Proukakis
Comments: 6 pages, 2 figures, submitted to the Proceedings of QFS '06
Subj-class: Statistical Mechanics
\\
We consider the dynamics of a dark soliton in an elongated harmonically
trapped Bose-Einstein condensate. A central question concerns the behavior at
finite temperatures, where dissipation arises due to the presence of a thermal
cloud. We study this problem using coupled Gross-Pitaevskii and $N$-body
simulations, which include the mean field coupling between the condensate and
thermal cloud. We find that the soliton decays relatively quickly even at very
low temperatures, with the decay rate increasing with rising temperature.
\\ ( http://arXiv.org/abs/cond-mat/0610082 , 35kb)
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Paper (*cross-listing*): hep-lat/0609054
Date: Wed, 27 Sep 2006 09:06:08 GMT (58kb)

Title: Field theoretic study of a cold Fermi gas in the unitary limit
Authors: Matthew Wingate
Comments: 7 pages. Talk delivered at The XXIV International Symposium on
Lattice Field Theory, Tucson, Arizona, July 2006. To appear in Proceedings of
Science
Subj-class: High Energy Physics - Lattice; Other; Superconductivity
\\
Trapped and cooled gases of alkali atoms can be manipulated to exhibit a
variety of interesting phenomena. For example, dilute gases of fermionic atoms,
in 2 hyperfine states, can be cooled to temperatures where they become
superfluid. An external field can be applied to tune the scattering length a.
When |a| exceeds the interparticle spacing, nonperturbative tools are needed to
study the system theoretically. The unitary limit, |a|\to\infty, is
particularly interesting due to its universality and symmetry. Lattice field
theory and effective field theory can be used to systematically calculate
properties of this system. Results are presented for the finite temperature
phase transition and for behavior near zero temperature.
\\ ( http://arXiv.org/abs/hep-lat/0609054 , 59kb)
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Paper: cond-mat/0610114
Date: Wed, 4 Oct 2006 12:49:48 GMT (405kb)

Title: Dynamical localization of matter wave solitons in managed barrier
potentials
Authors: Fatkhulla Kh. Abdullaev, Josselin Garnier
Comments: 10 pages, 6 figures
Subj-class: Other; Soft Condensed Matter
\\
The bright matter wave soliton propagation through a barrier with a rapidly
oscillating position is investigated. The averaged over rapid oscillations
Gross-Pitaevskii (GP) equation is derived. It is shown that the soliton is
dynamically trapped by the effective double-barrier.
The analytical predictions for the soliton effective dynamics is confirmed by
the numerical simulations of the full GP equation.
\\ ( http://arXiv.org/abs/cond-mat/0610114 , 405kb)
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Paper: cond-mat/0610116
Date: Wed, 4 Oct 2006 14:43:56 GMT (18kb)

Title: Resonant Dimer Relaxation in Cold Atoms with a Large Scattering Length
Authors: Eric Braaten (Ohio State U.), H.-W. Hammer (Bonn U.)
Comments: 4 pages, 2 ps figures
Report-no: HISKP-TH-06-26
Subj-class: Other
\\
Efimov physics refers to universal phenomena associated with a discrete
scaling symmetry in the 3-body problem with a large scattering length. The
first experimental evidence for Efimov physics was the recent observation of a
resonant peak in the 3-body recombination rate for 133Cs atoms with large
negative scattering length. There can also be resonant peaks in the atom-dimer
relaxation rate for large positive scattering length. We calculate the
atom-dimer relaxation rate as a function of temperature and show how
measurements of the relaxation rate can be used to determine accurately the
parameters that govern Efimov physics.
\\ ( http://arXiv.org/abs/cond-mat/0610116 , 18kb)
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Paper: cond-mat/0610117
Date: Wed, 4 Oct 2006 14:52:45 GMT (203kb)

Title: The Mathematics of the Bose Gas and its Condensation
Authors: Elliott H. Lieb, Robert Seiringer, Jan Philip Solovej, Jakob Yngvason
Comments: 213 pages. Slightly revised and extended version of Oberwolfach
Seminar Series, Vol. 34, Birkhaeuser (2005)
Subj-class: Statistical Mechanics
\\
This book surveys results about the quantum mechanical many-body problem of
the Bose gas that have been obtained by the authors over the last seven years.
These topics are relevant to current experiments on ultra-cold gases; they are
also mathematically rigorous, using many analytic techniques developed over the
years to handle such problems. Some of the topics treated are the ground state
energy, the Gross-Pitaevskii equation, Bose-Einstein condensation,
superfluidity, one-dimensional gases, and rotating gases. The book also
provides a pedagogical entry into the field for graduate students and
researchers.
\\ ( http://arXiv.org/abs/cond-mat/0610117 , 203kb)
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Paper: cond-mat/0610121
Date: Wed, 4 Oct 2006 19:29:48 GMT (68kb)

Title: Phase separation in a two species Bose mixture
Authors: T. Mishra, Ramesh V. Pai, B. P. Das
Comments: 5 pages, 5 figures
Subj-class: Statistical Mechanics; Other
\\
We study the ground state quantum phase diagram for a two species Bose
mixture in a one-dimensional optical lattice using the finite size density
matrix renormalization group(FSDMRG) method. We discuss our results for
different combinations of inter and intra species interaction strengths with
commensurate and incommensurate fillings of the bosons. The phases we have
obtained are superfluid, Mott insulator and a novel phase separation, where
different species reside in spatially separate regions. The spatially separated
phase is further classified into phase separated superfluid(PS-SF) and Mott
insulator(PS-MI). The phase separation appears for all the fillings we have
considered, whenever the inter-species interaction is slightly larger than the
intra-species interactions.
\\ ( http://arXiv.org/abs/cond-mat/0610121 , 68kb)
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Paper: quant-ph/0610019
Date: Tue, 3 Oct 2006 20:17:24 GMT (325kb)

Title: Realization of a superconducting atom chip
Authors: Thomas Nirrengarten (LKB - Lhomond), Angie Qarry (LKB - Lhomond),
C\'{e}dric Roux (LKB - Lhomond), Andreas Emmert (LKB - Lhomond), Gilles
Nogues (LKB - Lhomond), Michel Brune (LKB - Lhomond), Jean-Michel Raimond
(LKB - Lhomond), Serge Haroche (LKB - Lhomond, CDF)
Comments: Submitted to Phys. Rev. Lett
Proxy: ccsd ccsd-00103290
\\
We have trapped rubidium atoms in the magnetic field produced by a
superconducting atom chip operated at liquid Helium temperatures. Up to
$8.2\cdot 10^5$ atoms are held in a Ioffe-Pritchard trap at a distance of 440
$\mu$m from the chip surface, with a temperature of 40 $\mu$K. The trap
lifetime reaches 115 s at low atomic densities. These results open the way to
the exploration of atom--surface interactions and coherent atomic transport in
a superconducting environment, whose properties are radically different from
normal metals at room temperature.
\\ ( http://arXiv.org/abs/quant-ph/0610019 , 325kb)
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Paper: physics/0610022
Date: Tue, 3 Oct 2006 21:11:49 GMT (580kb)

Title: Compression and localization of an atomic cloud in a time dependent
optical lattice
Authors: Will Williams, M. Saffman
Comments: 9 Figures
Subj-class: Atomic Physics
\\
We analyze a method to compress a cloud of cold atoms in a far off resonance
optical lattice by dynamically changing the lattice parameters while cooling
the atoms with optical molasses. Particle motion in the time dependent lattice
is studied numerically using a three dimensional semiclassical model. We show
that smoothly varying the lattice spacing from a large to a small value results
in compression of more than 75% of the atoms initially in a Gaussian
distributed cloud with standard deviation of 50 $\mu$m into a single site of a
two-dimensional lattice. The lattice site has an area of $A=0.76 \lambda^2$
with $\lambda$ the wavelength of the trapping beam. We demonstrate that an
increase in the optical depth by a factor of at least 175 is possible.
\\ ( http://arXiv.org/abs/physics/0610022 , 580kb)
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Paper: physics/0610027
Date: Wed, 4 Oct 2006 13:04:49 GMT (924kb)

Title: Transport of launched cold atoms with a laser guide and pulsed magnetic
fields
Authors: Matthew J Pritchard, Aidan S Arnold, Simon L Cornish, David W
Hallwood, Chris V S Pleasant and Ifan G Hughes
Comments: 19 pages 11 figures
Subj-class: Atomic Physics; Optics
\\
We propose the novel combination of a laser guide and magnetic lens to
transport a cold atomic cloud. We have modelled the loading and guiding of a
launched cloud of cold atoms with the optical dipole force. We discuss the
optimum strategy for loading typically 30% of the atoms from a MOT and guiding
them vertically through 22cm. However, although the atoms are tightly confined
transversely, thermal expansion in the propagation direction still results in a
density loss of two orders of magnitude. By combining the laser guide with a
single impulse from a magnetic lens we show one can actually increase the
density of the guided atoms by a factor of 10.
\\ ( http://arXiv.org/abs/physics/0610027 , 924kb)
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Paper: cond-mat/0610135
Date: Thu, 5 Oct 2006 04:34:07 GMT (262kb)

Title: Complexity in parametric Bose-Hubbard Hamiltonians and structural
analysis of eigenstates
Authors: Moritz Hiller, Tsampikos Kottos, and T. Geisel
Comments: 4 pages, 4 figures
Subj-class: Other
Journal-ref: Phys. Rev. A 73, 061604(R), 2006
DOI: 10.1103/PhysRevA.73.061604
\\
We consider a family of chaotic Bose-Hubbard Hamiltonians (BHH) parameterized
by the coupling strength $k$ between neighboring sites. As $k$ increases the
eigenstates undergo changes, reflected in the structure of the Local Density of
States. We analyze these changes, both numerically and analytically, using
perturbative and semiclassical methods. Although our focus is on the quantum
trimer, the presented methodology is applicable for the analysis of longer
lattices as well.
\\ ( http://arXiv.org/abs/cond-mat/0610135 , 262kb)
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Paper: cond-mat/0610162
Date: Thu, 5 Oct 2006 19:53:40 GMT (21kb)

Title: Discrete symmetries and 1/3-quantum vortices in condensates of F=2 cold
atoms
Authors: Gordon W. Semenoff and Fei Zhou (UBC)
Comments: 4 pages, 2 figures included
Subj-class: Other
\\
In this Letter we study discrete symmetries of mean field manifolds of
condensates of F=2 cold atoms, and various unconventional quantum vortices.
Discrete quaternion symmetries result in two species of spin defects that can
only appear in integer vortices while {\em cyclic} symmetries are found to
result in a phase shift of $2\pi/3$ (or $4\pi/3$) and therefore 1/3- (or 2/3-)
quantum vortices in condensates. We also briefly discuss quaternion spin
vortices in biaxial nematic condensates, and 1/3-quantum vortices in
condensates of trimers.
\\ ( http://arXiv.org/abs/cond-mat/0610162 , 21kb)
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\\
Paper: quant-ph/0610029
Date: Thu, 5 Oct 2006 01:49:38 GMT (880kb)

Title: Cavity QED determination of atomic number statistics in optical lattices
Authors: W. Chen, D. Meiser, and P. Meystre
Comments: 10 pages revtex, 13 figures
\\
We study the reflection of two counter-propagating modes of the light field
in a ring resonator by ultracold atoms either in the Mott insulator state or in
the superfluid state of an optical lattice. We obtain exact numerical results
for a simple two-well model and carry out statistical calculations appropriate
for the full lattice case. We find that the dynamics of the reflected light
strongly depends on both the lattice spacing and the state of the matter-wave
field. Depending on the lattice spacing, the light field is sensitive to
various density-density correlation functions of the atoms. The light field and
the atoms become strongly entangled if the latter are in a superfluid state, in
which case the photon statistics typically exhibit complicated multimodal
structures.
\\ ( http://arXiv.org/abs/quant-ph/0610029 , 880kb)
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Replaced preprints:

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\\
Paper: cond-mat/0604186
replaced with revised version Fri, 29 Sep 2006 09:50:52 GMT (18kb)

Title: BEC-BCS crossover in an optical lattice
Authors: Arnaud Koetsier, D. B. M. Dickerscheid, H. T. C. Stoof
Comments: 4 pages, 3 figures
Report-no: ITP-UU-06/17
Subj-class: Statistical Mechanics
Journal-ref: Phys. Rev. A 74, 033621 (2006)
DOI: 10.1103/PhysRevA.74.033621
\\ ( http://arXiv.org/abs/cond-mat/0604186 , 18kb)
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\\
Paper: cond-mat/0606345
replaced with revised version Fri, 29 Sep 2006 03:28:00 GMT (293kb)

Title: First-principles quantum simulations of dissociation of molecular
condensates: Atom correlations in momentum space
Authors: C.M. Savage, P.E. Schwenn, and K.V. Kheruntsyan
Comments: Final published version, with updated references and minor
modifications
Subj-class: Other; Statistical Mechanics
Journal-ref: Phys. Rev. A 74, 033620 (2006)
DOI: 10.1103/PhysRevA.74.033620
\\ ( http://arXiv.org/abs/cond-mat/0606345 , 293kb)
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\\
Paper: cond-mat/0606470
replaced with revised version Thu, 28 Sep 2006 21:21:49 GMT (46kb)

Title: BCS-BEC crossover on the two-dimensional honeycomb lattice
Authors: Erhai Zhao, Arun Paramekanti (University of Toronto)
Comments: Revised - added section on the Fermi surface evolution, corrected
error in superfluid density, added possible implications for cuprates
Subj-class: Superconductivity; Strongly Correlated Electrons
\\ ( http://arXiv.org/abs/cond-mat/0606470 , 46kb)
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\\
Paper: cond-mat/0607004
replaced with revised version Thu, 28 Sep 2006 22:58:02 GMT (388kb)

Title: Evidence for Superfluidity of Ultracold Fermions in an Optical Lattice
Authors: J. K. Chin, D. E. Miller, Y. Liu, C. Stan, W. Setiawan, C. Sanner, K.
Xu, W. Ketterle
Comments: accepted for publication in Nature
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0607004 , 388kb)
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\\
Paper: cond-mat/0607297
replaced with revised version Thu, 28 Sep 2006 23:34:14 GMT (138kb)

Title: Melting of Discrete Vortices via Quantum Fluctuations
Authors: Chaohong Lee, Tristram J. Alexander, and Yuri S. Kivshar
Comments: Revised version, 4 pages, 5 figures, Accepted for publication in
Physical Review Letters
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0607297 , 138kb)
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\\
Paper: cond-mat/0607361
replaced with revised version Fri, 29 Sep 2006 08:38:42 GMT (87kb)

Title: Collective excitations of a Bose-Einstein condensate in an anharmonic
trap
Authors: Guan-Qiang Li, Li-Bin Fu, Ju-Kui Xue, Xu-Zong Chen, and Jie Liu
Comments: 5 pages, 4 figures
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\ ( http://arXiv.org/abs/cond-mat/0607361 , 87kb)
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\\
Paper: cond-mat/0609337
replaced with revised version Fri, 29 Sep 2006 08:17:20 GMT (386kb)

Title: Quantum Entanglement Manifestation of Transition to Nonlinear
Self-trapping for Bose-Einstein Condensates in a Symmetric Double-Well
Authors: Li-Bin Fu and Jie Liu
Comments: 6 pages, 5 figures
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\ ( http://arXiv.org/abs/cond-mat/0609337 , 386kb)
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\\
Paper: quant-ph/0509094
replaced with revised version Fri, 29 Sep 2006 17:13:55 GMT (29kb)

Title: Single-cell atomic quantum memory for light
Authors: Tomas Opatrny
Comments: 6 pages, 2 figures, to be published in Phys. Rev. A
\\ ( http://arXiv.org/abs/quant-ph/0509094 , 29kb)
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\\
Paper: cond-mat/0510194
replaced with revised version Mon, 2 Oct 2006 19:38:26 GMT (144kb)

Title: Ramping fermions in optical lattices across a Feshbach resonance
Authors: Helmut G. Katzgraber, Aniello Esposito, Matthias Troyer
Comments: 9 pages, 7 figures
Subj-class: Other
Journal-ref: Phys. Rev. A 74, 043602 (2006)
DOI: 10.1103/PhysRevA.74.043602
\\ ( http://arXiv.org/abs/cond-mat/0510194 , 144kb)
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\\
Paper: cond-mat/0511294
replaced with revised version Mon, 2 Oct 2006 17:21:43 GMT (836kb)

Title: Variational Cluster Perturbation Theory for Bose-Hubbard models
Authors: W. Koller and N. Dupuis
Comments: v1) 10 pages, 6 figures. v2) Final version as published
Subj-class: Other; Statistical Mechanics
Journal-ref: J. Phys.: Condens. Matter 18 (2006) 9525-9540
DOI: 10.1088/0953-8984/18/41/019
\\ ( http://arXiv.org/abs/cond-mat/0511294 , 836kb)
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\\
Paper: cond-mat/0602334
replaced with revised version Mon, 2 Oct 2006 16:49:23 GMT (111kb)

Title: Hysteresis effects in rotating Bose-Einstein condensates
Authors: B. Jackson and C. F. Barenghi
Comments: 16 pages, 7 figures; revised after referees' reports
Subj-class: Statistical Mechanics
\\ ( http://arXiv.org/abs/cond-mat/0602334 , 111kb)
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\\
Paper: cond-mat/0605198
replaced with revised version Mon, 2 Oct 2006 14:26:21 GMT (738kb)

Title: Cooling toolbox for atoms in optical lattices
Authors: M. Popp, J.-J. Garcia-Ripoll, K. G. H. Vollbrecht and J. I. Cirac
Comments: 14 pages, 13 figures
Subj-class: Other
Journal-ref: New J. Phys. 8, 164 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0605198 , 738kb)
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\\
Paper: cond-mat/0605207
replaced with revised version Mon, 2 Oct 2006 19:02:24 GMT (43kb)

Title: Entanglement entropy and entanglement witnesses in models of strongly
interacting low-dimensional fermions
Authors: V. V. Fran\c{c}a and K. Capelle
Comments: 5 pages, 5 figures, accepted by PRA
Subj-class: Strongly Correlated Electrons; Statistical Mechanics
\\ ( http://arXiv.org/abs/cond-mat/0605207 , 43kb)
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\\
Paper: cond-mat/0607463
replaced with revised version Sat, 30 Sep 2006 01:06:06 GMT (14kb)

Title: Quantum insulating states of F=2 cold atoms in optical lattices
Authors: Fei Zhou and Gordon W. Semenoff (PITP and UBC)
Comments: 4 pages, 1 figure included; references updated. To appear in Phys.
Rev. Lett
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0607463 , 14kb)
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\\
Paper: physics/0609145
replaced with revised version Fri, 29 Sep 2006 20:10:14 GMT (73kb)

Title: Optical Feshbach resonances of Alkaline-Earth atoms in a 1D or 2D
optical lattice
Authors: Pascal Naidon and Paul S. Julienne
Comments: 12 pages, 4 figures. Typos were corrected and a connection was made
to the fermionization of bosons
Subj-class: Atomic Physics
\\ ( http://arXiv.org/abs/physics/0609145 , 73kb)
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\\
Paper: cond-mat/0606043
replaced with revised version Tue, 3 Oct 2006 19:45:17 GMT (397kb)

Title: Zero Temperature Thermodynamics of Asymmetric Fermi Gases at Unitarity
Authors: Aurel Bulgac and Michael McNeil Forbes
Comments: 4 pages and 3 figures, revtex4 and an additional extensive appendix
meant to appear only online
Report-no: NT_at_UW-06-12
Subj-class: Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0606043 , 397kb)
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\\
Paper: cond-mat/0607434
replaced with revised version Tue, 3 Oct 2006 07:44:26 GMT (245kb)

Title: Thermal dissipation in quantum turbulence
Authors: Michikazu Kobayashi and Makoto Tsubota
Comments: 4 pages, 6 figures, submitted to APS
Subj-class: Disordered Systems and Neural Networks; Statistical Mechanics
\\ ( http://arXiv.org/abs/cond-mat/0607434 , 245kb)
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\\
Paper: cond-mat/0608135
replaced with revised version Mon, 2 Oct 2006 22:36:21 GMT (376kb)

Title: Disruption of reflecting Bose-Einstein condensates due to inter-atomic
interactions and quantum noise
Authors: R.G. Scott, D.A.W. Hutchinson and C.W. Gardiner
Comments: 5 figures
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0608135 , 376kb)
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\\
Paper: cond-mat/0605102
replaced with revised version Tue, 3 Oct 2006 21:21:53 GMT (242kb)

Title: Topological defects and the superfluid transition of the $s=1$ spinor
condensate in two dimensions
Authors: Subroto Mukerjee, Cenke Xu, and J. E. Moore
Comments: 4 pages, 2 figures; published version
Subj-class: Other
Journal-ref: Phys. Rev. Lett. 97, 120406 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0605102 , 242kb)
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\\
Paper: cond-mat/0606265
replaced with revised version Wed, 4 Oct 2006 18:20:11 GMT (153kb)

Title: Spinful bosons in an optical lattice
Authors: Sara Bergkvist, Ian McCulloch, Anders Rosengren
Comments: Minor revisions and clarifications
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0606265 , 153kb)
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\\
Paper: cond-mat/0608455
replaced with revised version Wed, 4 Oct 2006 17:23:01 GMT (823kb)

Title: Deformation of a Trapped Fermi Gas with Unequal Spin Populations
Authors: G. B. Partridge, Wenhui Li, Y. A. Liao, R. G. Hulet, M. Haque & H. T.
C. Stoof
Comments: Accepted for publication in Physical Review Letters
Subj-class: Other; Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0608455 , 823kb)
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Till next week,
Matt.

--
=========================================================================
Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email: mdavis_at_physics.uq.edu.au
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Australia.                    http://www.physics.uq.edu.au/people/mdavis/
=========================================================================
Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org
http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/
=========================================================================
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=========================================================================

Received on Tue Oct 10 2006 - 10:36:57 EST

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