# Matt's arXiv selection: week ending 17th November 2006.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Mon, 20 Nov 2006 11:51:23 +1000 (EST)

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

Thirty one new papers listed this week.

New abstracts:

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Paper: cond-mat/0611264
Date: Thu, 9 Nov 2006 21:14:18 GMT (43kb)

Title: The Fermion Monte Carlo revisited
Authors: Roland Assaraf (LCT), Michel Caffarel (LPQ), Anatole Khelif (ELM)
Comments: 49 pages with 4 postscript figures
Proxy: ccsd hal-00112854
Report-no: LCPQ-2006
Subj-class: Strongly Correlated Electrons
\\
In this work we present a detailed study of the Fermion Monte Carlo algorithm
(FMC), a recently proposed stochastic method for calculating fermionic
ground-state energies [M.H. Kalos and F. Pederiva, Phys. Rev. Lett. vol. 85,
3547 (2000)]. A proof that the FMC method is an exact method is given. In this
work the stability of the method is related to the difference between the
lowest (bosonic-type) eigenvalue of the FMC diffusion operator and the exact
fermi energy. It is shown that within a FMC framework the lowest eigenvalue of
the new diffusion operator is no longer the bosonic ground-state eigenvalue as
in standard exact Diffusion Monte Carlo (DMC) schemes but a modified value
which is strictly greater. Accordingly, FMC can be viewed as an exact DMC
method built from a correlated diffusion process having a reduced Bose-Fermi
gap. As a consequence, the FMC method is more stable than any transient method
(or nodal release-type approaches). We illustrate the various ideas presented
in this work with calculations performed on a very simple model having only
nine states but a full sign problem. Already for this toy model it is clearly
seen that FMC calculations are inherently uncontrolled.
\\ ( http://arXiv.org/abs/cond-mat/0611264 , 43kb)
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Paper: cond-mat/0611279
Date: Fri, 10 Nov 2006 11:24:52 GMT (523kb)

Title: Non-equilibrium dynamics: Studies of reflection of Bose-Einstein
condensates
Authors: R. G. Scott, C. W. Gardiner, and D. A. W. Hutchinson
Subj-class: Statistical Mechanics
\\
The study of the non-equilibrium dynamics in Bose-Einstein condensed gases
has been dominated by the zero-temperature, mean field Gross-Pitaevskii
formalism. Motivated by recent experiments on the reflection of condensates
from silicon surfaces, we revisit the so-called {\em classical field}
description of condensate dynamics, which incorporates the effects of quantum
noise and can also be generalized to include thermal effects. The noise is
included in a stochastic manner through the initial conditions. We show that
the inclusion of such noise is important in the quantitative description of the
recent reflection experiments.
\\ ( http://arXiv.org/abs/cond-mat/0611279 , 523kb)
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Paper: cond-mat/0611285
Date: Fri, 10 Nov 2006 17:11:01 GMT (14kb)

Title: Note on "Collective Excitations of a Degenerate Gas at the BEC-BCS
Crossover", Phys. Rev. Lett. 92, 203201 (2004)
Authors: A. Altmeyer, S. Riedl, C. Kohstall, M.J. Wright, J. Hecker Denschlag,
and R. Grimm
Subj-class: Other; Superconductivity
\\
We present a reinterpretation of our previous results on the radial
compression mode of a degenerate quantum gas in the BEC-BCS crossover in [1].
We show that our former data are consistent with other experimental and
theoretical work, when the ellipticity of the optical trapping potential in [1]
is properly taken into account.
\\ ( http://arXiv.org/abs/cond-mat/0611285 , 14kb)
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Paper: cond-mat/0611286
Date: Fri, 10 Nov 2006 17:12:39 GMT (666kb)

Title: Gap solitons in Bose-Einstein condensates in linear and nonlinear
optical lattices
Authors: Fatkhulla Abdullaev, Abdulaziz Abdumalikov, Ravil Galimzyanov
Subj-class: Other
\\
Properties of localized states on array of BEC confined to a potential,
representing superposition of linear and nonlinear optical lattices are
investigated. For a shallow lattice case the coupled mode system has been
derived. The modulational instability of nonlinear plane waves is analyzed. We
revealed new types of gap solitons and studied their stability. For the first
time a moving soliton solution has been found. Analytical predictions are
confirmed by numerical simulations of the Gross-Pitaevskii equation with
jointly acting linear and nonlinear periodic potentials.
\\ ( http://arXiv.org/abs/cond-mat/0611286 , 666kb)
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Paper (*cross-listing*): hep-th/0611090
Date: Wed, 8 Nov 2006 10:52:52 GMT (32kb)

Title: Bosonization and Scale Invariance on Quantum Wires
Authors: B. Bellazzini, M. Mintchev and P. Sorba
Comments: LaTex 30+1 pages, 2 figures
Report-no: IFUP-TH 25/2006, LAPTH-1166/06
Subj-class: High Energy Physics - Theory; Mesoscopic Systems and Quantum Hall
Effect; Mathematical Physics
\\
We develop a systematic approach to bosonization and vertex algebras on
quantum wires of the form of star graphs. The related bosonic fields propagate
freely in the bulk of the graph, but interact at its vertex. Our framework
covers all possible interactions preserving unitarity. Special attention is
devoted to the scale invariant interactions, which determine the critical
properties of the system. Using the associated scattering matrices, we give a
complete classification of the critical points on a star graph with any number
of edges. Critical points where the system is not invariant under wire
permutations are discovered. By means of an appropriate vertex algebra we
perform the bosonization of fermions and solve the massless Thirring model. In
this context we derive an explicit expression for the conductance and
investigate its behavior at the critical points. A simple relation between the
conductance and the Casimir energy density is pointed out.
\\ ( http://arXiv.org/abs/hep-th/0611090 , 32kb)
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Paper: cond-mat/0611295
Date: Sat, 11 Nov 2006 04:17:15 GMT (47kb)

Title: Oscillatory vortex interaction in a gapless fermion superfluid with spin
population imbalance
Authors: Vladimir M. Stojanovic, W. Vincent Liu, Yong Baek Kim
Subj-class: Superconductivity; Other
\\
Using effective field theory approach we study a homogeneous superfluid state
with a single (gapless) Fermi surface, recently suggested as a possible phase
for an ultracold Fermi gas with spin-population imbalance. We find an
unconventional form of the interaction between vortices. The presence of
gapless fermions gives rise to an attractive long-range potential oscillating
in space, analogous to the RKKY magnetic interaction in metals. Our study then
leads to an interesting question as to the nature of the vortex lattice in the
presence of competition between the usual repulsive logarithmic Coulomb and
fermion-induced attractive oscillatory interactions.
\\ ( http://arXiv.org/abs/cond-mat/0611295 , 47kb)
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Paper: cond-mat/0611312
Date: Mon, 13 Nov 2006 05:26:28 GMT (23kb)

Title: Bragg spectroscopy of a cigar shaped Bose condensate in optical lattices
Authors: Tarun Kanti Ghosh and Kazushige Machida
Subj-class: Other
\\
We study properties of excited states of an array of weakly coupled
quasi-two-dimensional Bose condensates by using the hydrodynamic theory. We
calculate multibranch Bogoliubov-Bloch spectrums and its corresponding
eigenfunctions. The spectrum of the axial excited states and its eigenfunctions
strongly depends on the coupling among various discrete radial modes within a
given symmetry. This mode coupling is due to the presence of radial trapping
potential. The multibranch nature of the Bogoliubov-Bloch spectrum and its
dependence on the mode-coupling can be realized by analyzing dynamic structure
factor and momentum transferred to the system in Bragg spectroscopy
experiments. We also study dynamic structure factor and momentum transferred to
the condensate due to the Bragg spectroscopy experiment.
\\ ( http://arXiv.org/abs/cond-mat/0611312 , 23kb)
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Paper: cond-mat/0611321
Date: Mon, 13 Nov 2006 10:14:44 GMT (612kb)

Title: One-particle dynamical correlations in the one-dimensional Bose gas
Authors: Jean-Sebastien Caux, Pasquale Calabrese, and Nikita A. Slavnov
Subj-class: Statistical Mechanics
\\
The momentum- and frequency-dependent one-body correlation function of the
one-dimensional interacting Bose gas (Lieb-Liniger model) in the repulsive
regime is studied using the Algebraic Bethe Ansatz and numerics. We first
provide a determinant representation for the field form factor which is
well-adapted to numerical evaluation. The correlation function is then
reconstructed to high accuracy for systems with finite but large numbers of
particles, for a wide range of values of the interaction parameter. Our results
are extensively discussed, in particular their specialization to the static
case.
\\ ( http://arXiv.org/abs/cond-mat/0611321 , 612kb)
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Paper: cond-mat/0611332
Date: Mon, 13 Nov 2006 17:15:50 GMT (331kb)

Title: Lifshitz-like transition and enhancement of correlations in a rotating
bosonic ring lattice
Authors: Ana Maria Rey, Keith Burnett, Indubala I. Satija and Charles W. Clark
Subj-class: Other
\\
We study the effects of rotation on one-dimensional ultra-cold bosons
confined to a ring lattice. For commensurate systems, at a critical value of
the rotation frequency, an infinitesimal interatomic interaction energy opens a
gap in the excitation spectrum, fragments the ground state into a macroscopic
superposition of two states with different circulation and generates a sudden
change in the topology of the momentum distribution. These features are
reminiscent of the topological changes in the Fermi surface that occurs in the
Lifshitz transition in fermionic systems. The entangled nature of the ground
state induces a strong enhancement of quantum correlations and decreases the
threshold for the Mott insulator transition. In contrast to the commensurate
case, the incommensurate lattice is rather insensitive to rotation. Our studies
demonstrate the utility of noise correlations as a tool for identifying new
physics in strongly correlated systems.
\\ ( http://arXiv.org/abs/cond-mat/0611332 , 331kb)
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Paper: quant-ph/0611121
Date: Sat, 11 Nov 2006 22:56:52 GMT (71kb)

Title: A measurement-based measure of the size of macroscopic quantum
superpositions
Authors: Jan Ivar Korsbakken, K. Birgitta Whaley, Jonathan DuBois, J. Ignacio
Cirac
Comments: 20 pages, 22 figures. Submitted to Phys. Rev. A
\\
Recent experiments claiming formation of quantum superposition states in near
macroscopic systems raise the question of how the sizes of general quantum
superposition states in an interacting system are to be quantified. We propose
here a measure of size for such superposition states that is based on what
measurements can be performed to probe and distinguish the different branches
of the state. The measure allows comparison of the effective size for
superposition states in very different physical systems. It can be applied to a
very general class of superposition states and reproduces known results for
near-ideal cases. Comparison with a prior measure based on analysis of
coherence between branches indicates that significantly smaller effective
superposition sizes result from our measurement-based measure. Application to a
system of interacting bosons in a double-well trapping potential shows that the
effective superposition size is strongly dependent on the relative magnitude of
the barrier height and interparticle interaction.
\\ ( http://arXiv.org/abs/quant-ph/0611121 , 71kb)
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Paper: quant-ph/0611128
Date: Sat, 11 Nov 2006 18:44:39 GMT (190kb)

Title: Dual species matter qubit entangled with light
Authors: S.-Y. Lan, S. D. Jenkins, T. Chaneliere, D. N. Matsukevich, C. J.
Campbell, R. Zhao, T. A. B. Kennedy, and A. Kuzmich
\\
We propose and demonstrate an atomic qubit based on a cold
$^{85}$Rb-$^{87}$Rb isotopic mixture, entangled with a frequency-encoded
optical qubit. The interface of an atomic qubit with a single spatial light
mode, and the ability to independently address the two atomic qubit states,
should provide the basic element of an interferometrically robust quantum
network.
\\ ( http://arXiv.org/abs/quant-ph/0611128 , 190kb)
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Paper: quant-ph/0611132
Date: Sun, 12 Nov 2006 18:21:45 GMT (10kb)

Title: Delocalized Entanglement of Atoms in optical Lattices
Authors: K. G. H. Vollbrecht and J. I. Cirac
\\
We show how to detect and quantify entanglement of atoms in optical lattices
in terms of correlations functions of the momentum distribution. These
distributions can be measured directly in the experiments. We introduce two
kinds of entanglement measures related to the position and the spin of the
atoms.
\\ ( http://arXiv.org/abs/quant-ph/0611132 , 10kb)
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Paper: quant-ph/0611132
Date: Sun, 12 Nov 2006 18:21:45 GMT (10kb)

Title: Delocalized Entanglement of Atoms in optical Lattices
Authors: K. G. H. Vollbrecht and J. I. Cirac
\\
We show how to detect and quantify entanglement of atoms in optical lattices
in terms of correlations functions of the momentum distribution. These
distributions can be measured directly in the experiments. We introduce two
kinds of entanglement measures related to the position and the spin of the
atoms.
\\ ( http://arXiv.org/abs/quant-ph/0611132 , 10kb)
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Paper: physics/0611119
Date: Mon, 13 Nov 2006 13:23:13 GMT (200kb)

Title: The discovery of superfluidity
Authors: Sebastien Balibar (LPS)
Proxy: ccsd hal-00113242
Subj-class: History of Physics
\\
Superfluidity is a remarkable manifestation of quantum mechanics at the
took place at a particularly difficult period of the twentieth century. A
special emphasis is given to the role of J.F. Allen, D. Misener, P. Kapitza, F.
London, L. Tisza and L.D. Landau. The nature and the importance of their
respective contributions are analyzed and compared. Of particular interest is
the controversy between Landau on one side, London and Tisza on the other,
concerning the relevance of Bose-Einstein condensation to the whole issue, and
also on the nature of thermal excitations in superfluid helium 4. In order to
aid my understanding of this period, I have collected several testimonies which
inform us about the work and attitude of these great scientists.
\\ ( http://arXiv.org/abs/physics/0611119 , 200kb)
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Paper: cond-mat/0611357
Date: Tue, 14 Nov 2006 10:55:28 GMT (24kb)

Title: Bose-Einstein-condensed systems in random potentials
Authors: V.I. Yukalov and R. Graham
Subj-class: Statistical Mechanics
\\
The properties of systems with Bose-Einstein condensate in external
time-independent random potentials are investigated in the frame of a
self-consistent stochastic mean-field approximation. General considerations are
presented, which are valid for finite temperatures, arbitrary strengths of the
interaction potential, and for arbitrarily strong disorder potentials. The
special case of a spatially uncorrelated random field is then treated in more
detail. For this case it is shown that the system consists of three components,
condensed particles, uncondensed particles and a glassy density-fraction, but
that the pure Bose glass phase with only a glassy density does not appear. The
theory predicts a first-order phase transition for increasing disorder
parameter, where the condensate fraction and the superfluid fraction
energy, the stability conditions, the compressibility, the structure factor,
and the sound velocity are analysed.
\\ ( http://arXiv.org/abs/cond-mat/0611357 , 24kb)
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Paper: cond-mat/0611376
Date: Tue, 14 Nov 2006 16:57:28 GMT (28kb)

Title: The angular momentum of a magnetically trapped atomic condensate
Authors: P. Zhang, H. H. Jen, C. P. Sun and L. You
Subj-class: Other
\\
For an atomic condensate in an axially symmetric magnetic trap, the sum of
the axial components of the orbital angular momentum and the hyperfine spin is
conserved. Inside an Ioffe-Pritchard trap (IPT) whose magnetic field (B-field)
is not axially symmetric, the difference of the two becomes surprisingly
conserved. In this paper we investigate the relationship between the values of
the sum/difference angular momentums for an atomic condensate inside a magnetic
trap and the associated gauge potential induced by the adiabatic approximation.
Our result provides significant new insight into the vorticity of magnetically
trapped atomic quantum gases.
\\ ( http://arXiv.org/abs/cond-mat/0611376 , 28kb)
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Paper: cond-mat/0611379
Date: Tue, 14 Nov 2006 18:25:58 GMT (143kb)

Title: Predicting spinor condensate dynamics from simple principles
Authors: M. Moreno-Cardoner, J. Mur-Petit, M. Guilleumas, A. Polls, A. Sanpera,
and M. Lewenstein
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\
We study the dynamics of spinor F=1 condensates both at zero and finite
temperature for arbitrary initial spin configurations in elongated 1D
condensates. We find that the rich spin dynamics exhibited by these systems,
can be predicted from surprisingly simple principles applied to the homogeneous
system: by imposing minimization of energy at zero temperature, and by
maximization of entropy at finite temperature. These predictions, which can
serve as a guidance for future experiments, are corroborated by numerical
simulations in the confined system and compare qualitatively well with recent
experimental observations for a wide varietey of initial parameters
(magnetization, spin component population and relative phases). The formation
of spin domains in the confined system is also discussed.
\\ ( http://arXiv.org/abs/cond-mat/0611379 , 143kb)
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Paper: quant-ph/0611148
Date: Tue, 14 Nov 2006 09:06:06 GMT (245kb)

Title: Localization of atomic ensembles via superfluorescence
Authors: M. Macovei, J. Evers, C. H. Keitel, M. S. Zubairy
\\
The sub-wavelength localization of an ensemble of atoms concentrated to a
small volume in space is investigated. The localization relies on the
interaction of the ensemble with a standing wave laser field. The light
scattered in the interaction of standing wave field and atom ensemble depends
on the position of the ensemble relative to the standing wave nodes. This
relation can be described by a fluorescence intensity profile, which depends on
the standing wave field parameters, the ensemble properties, and which is
modified due to collective effects in the ensemble of nearby particles. We
demonstrate that the intensity profile can be tailored to suit different
localization setups. Finally, we apply these results to two localization
schemes. First, we show how to localize an ensemble fixed at a certain position
in the standing wave field. Second, we discuss localization of an ensemble
passing through the standing wave field.
\\ ( http://arXiv.org/abs/quant-ph/0611148 , 245kb)
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Paper: quant-ph/0611152
Date: Tue, 14 Nov 2006 11:34:26 GMT (7kb)

Title: Casimir-Polder force density between an atom and a conducting wall
Authors: R. Messina, R. Passante
\\
In this paper we calculate the Casimir-Polder force density (force per unit
area acting on the elements of the surface) on a metallic plate placed in front
of a neutral atom. To obtain the force density we use the quantum operator
associated to the electromagnetic stress tensor. We explicitly show that the
integral of this force density over the plate reproduces the total force acting
on the plate. This result shows that, although the force is obtained as a sum
of surface element-atom contributions, the stress-tensor method includes also
nonadditive components of Casimir-Polder forces in the evaluation of the force
acting on a macroscopic object.
\\ ( http://arXiv.org/abs/quant-ph/0611152 , 7kb)
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Paper: cond-mat/0611386
Date: Wed, 15 Nov 2006 15:20:30 GMT (40kb)

Title: Topological defects, "magnetic charges" and coherence in dipolar
excitonic condensates
Authors: Egor Babaev
Subj-class: Superconductivity; Mesoscopic Systems and Quantum Hall Effect
\\
The current progress in fabrication technology raised the expectation for the
creation of excitonic condensates in semiconductor bilayers. We discuss an
effective model for such bilayers paying special attention to dynamics of the
gauge field. We find topological defects which emit radial quantized magnetic
flux and identify a regime where the effective model has planar electrodynamics
with effective "magnetic charges". We also find that the system possesses a
Kosterlitz-Thouless transition with a non-universal superfluid density jump and
propose experimental probes for these phenomena.
\\ ( http://arXiv.org/abs/cond-mat/0611386 , 40kb)
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Paper: cond-mat/0611402
Date: Wed, 15 Nov 2006 11:27:43 GMT (569kb)

Title: Coexisting ordinary elasticity and superfluidity in a model of
defect-free supersolid
Authors: Christophe Josserand, Yves Pomeau and Sergio Rica
Subj-class: Other
\\
We present the mechanics of a model of supersolid in the frame of the
Gross-Pitaevskii equation at $T=0K$ that do not require defects nor vacancies.
A set of coupled nonlinear partial differential equations plus boundary
conditions is derived. The mechanical equilibrium is studied under external
constrains as steady rotation or external stress. Our model displays a
paradoxical behavior: the existence of a non classical rotational inertia
fraction in the limit of small rotation speed and no superflow under small (but
finite) stress nor external force. The only matter flow for finite stress is
due to plasticity.
\\ ( http://arXiv.org/abs/cond-mat/0611402 , 569kb)
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Paper: cond-mat/0611405
Date: Wed, 15 Nov 2006 13:54:01 GMT (142kb)

Title: Critical velocities in superfluids and the nucleation of vortices
Authors: E. Varoquaux
Comments: 33 pages, 16 figures, review paper submitted to C.R. Acad. Sci.
(Paris)
Subj-class: Other
\\
The problem of critical velocities in superfluids, that is the comprehension
of superfluidity breakdown by flow, has been long standing. One difficulty
stems from the existence of several breakdown mechanisms. A major advance has
come from the observation of single $2\pi$ phase slips, which arise from the
nucleation of quantised vortices, that is, their creation {\it ex nihilo}. The
statistical properties of the nucleation process in both the thermal regime and
the quantum regime are identified and analysed: vortex nucleation provides a
well-documented case of macroscopic quantum tunnelling (MQT). In particular, a
close scrutiny of the experimental data obtained on ultra-pure $^4$He reveals
the influence of damping on tunnelling, a rare occurrence where the effect of
the environment on MQT can be studied.
\\ ( http://arXiv.org/abs/cond-mat/0611405 , 142kb)
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Paper: cond-mat/0611416
Date: Wed, 15 Nov 2006 19:41:55 GMT (33kb)

Title: Ensemble averaged coherent state path integral for disordered bosons
with a repulsive interaction (Derivation of mean field equations)
Authors: Bernhard mieck
Comments: 37 pages; a second part, particulaly applicable for d=2 spatial
dimensions, is in preparation ('Derivation of a nonlinear sigma model')
Subj-class: Statistical Mechanics; Disordered Systems and Neural Networks
\\
We consider bosonic atoms with a repulsive contact interaction in a trap
potential for a Bose-Einstein condensation and additionally include a random
potential. The ensemble averages for two models of static and dynamic disorder
are performed and investigated in parallel. The bosonic many body systems of
the two disorder models are represented by coherent state path integrals on the
Keldysh time contour which allow exact ensemble averages for zero and finite
temperatures. These ensemble averages of coherent state path integrals
therefore present alternatives to replica field theories or supersymmetric
averaging techniques.
\\ ( http://arXiv.org/abs/cond-mat/0611416 , 33kb)
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Paper (*cross-listing*): nucl-th/0611046
Date: Tue, 14 Nov 2006 05:47:12 GMT (49kb)

Title: Superfluidity in neutron stars and cold atoms
Authors: A. Schwenk
Comments: 3 pages, 2 figures, talk at Quark Confinement and the Hadron Spectrum
Subj-class: Nuclear Theory; Superconductivity
\\
We discuss superfluidity in neutron matter, with particular attention to
induced interactions and to universal properties accessible with cold atoms.
\\ ( http://arXiv.org/abs/nucl-th/0611046 , 49kb)
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Paper: physics/0611155
Date: Wed, 15 Nov 2006 17:01:30 GMT (194kb)

Title: Probing the electron EDM with cold molecules
Authors: B.E. Sauer, H.T. Ashworth, J.J. Hudson, M.R. Tarbutt, E.A. Hinds
Comments: 8 pages, 6 figures, proceedings of ICAP 2006
Subj-class: Atomic Physics
Journal-ref: Atomic Physics 20, pp. 44-52 (2006)
\\
We present progress towards a new measurement of the electron electric dipole
moment using a cold supersonic beam of YbF molecules. Data are currently being
taken with a sensitivity of $10^{-27}\textrm{e.cm}/\sqrt{\textrm{day}}$. We
therefore expect to make an improvement over the Tl experiment of Commins'
group, which currently gives the most precise result. We discuss the systematic
and statistical errors and comment on the future prospect of making a
measurement at the level of $10^{-29}\textrm{e.cm}/\sqrt{\textrm{day}}$.
\\ ( http://arXiv.org/abs/physics/0611155 , 194kb)
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Paper: physics/0611154
Date: Wed, 15 Nov 2006 16:41:26 GMT (895kb)

Title: Optical ferris wheel for ultracold atoms
Authors: S. Franke-Arnold, J. Leach, M. J. Padgett, V. E. Lembessis, D.
Ellinas, A. J. Wright, J. M. Girkin, P. Ohberg, A. S. Arnold
Subj-class: Optics; Atomic Physics
\\
We propose a versatile optical ring lattice suitable for trapping cold and
quantum degenerate atomic samples at discrete angular positions. We demonstrate
the realisation of intensity patterns generated from Laguerre-Gauss ($\exp(i \ell\theta)$) modes with different $\ell$ indices. The ring lattice can have
either intensity maxima or minima, suitable for trapping in red or blue detuned
light, and it can be rotated by introducing a frequency shift between the
Laguerre Gauss modes. The potential wells can be joined to form a uniform ring
trap, making it ideal for studying persistent currents and the Mott insulator
transition in a ring geometry.
\\ ( http://arXiv.org/abs/physics/0611154 , 895kb)
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Paper (*cross-listing*): cs.DL/0611060
Date: Tue, 14 Nov 2006 14:48:15 GMT (118kb)

Title: The effect of 'Open Access' upon citation impact: An analysis of ArXiv's
Condensed Matter Section
Authors: Henk F. Moed
Comments: Version 13 November 2006. 16 pages, 6 figures, 2 tables
Subj-class: Digital Libraries; Information Retrieval
\\
deposited in the Condensed Matter section of the preprint server ArXiv (hosted
by Cornell University), and subsequently published in a scientific journal,
compares to that of articles in the same journal that were not deposited in
that archive. Its principal aim is to further illustrate and roughly estimate
the effect of two factors, 'early view' and 'quality bias', upon differences in
citation impact between these two sets of papers, using citation data from
Thomson Scientific's Web of Science. It presents estimates for a number of
journals in the field of condensed matter physics. In order to discriminate
between an 'open access' effect and an early view effect, longitudinal citation
data was analysed covering a time period as long as 7 years. Quality bias was
measured by calculating ArXiv citation impact differentials at the level of
individual authors publishing in a journal, taking into account co-authorship.
The analysis provided evidence of a strong quality bias and early view effect.
Correcting for these effects, there is in a sample of 6 condensed matter
physics journals studied in detail, no sign of a general 'open access
advantage' of papers deposited in ArXiv. The study does provide evidence that
ArXiv accelerates citation, due to the fact that that ArXiv makes papers
earlier available rather than that it makes papers freely available.
\\ ( http://arXiv.org/abs/cs/0611060 , 118kb)
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Paper: cond-mat/0611421
Date: Thu, 16 Nov 2006 02:53:26 GMT (51kb)

Title: Pairing in Asymmetrical Fermi Systems with Intra- and Inter-Species
Correlations
Authors: Renyuan Liao and Khandker F. Quader (Dept of Physics, Kent State
University)
Subj-class: Superconductivity; Strongly Correlated Electrons
\\
We consider inter- and intra-species pairing interactions in an asymmetrical
Fermi system. Using equation of motion method, we obtain coupled mean-field
equations for superfluid gap functions and population densities. We construct a
phase diagram across BCS-BEC regimes. Due to intra-species correlations, the
BCS singlet superfluid state can sustain finite polarizations, $P$. For larger
$P$, we find phase separations in BCS and BEC regimes. A superfluid phase
exists for all $P$ deep in BEC regime. Our results may apply to pairing in
ultracold fermions, nuclear and quark matter physics.
\\ ( http://arXiv.org/abs/cond-mat/0611421 , 51kb)
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Paper: cond-mat/0611426
Date: Thu, 16 Nov 2006 08:54:45 GMT (3kb)

Title: Comment on "Classifying Novel Phases of Spinor Atoms"
Authors: S-.K. Yip
Subj-class: Superconductivity
\\
Comment on "Classifying Novel Phases of Spinor Atoms", Phys. Rev. Lett. 97,
180412 (2006) by R. Barnett, A. Turner and E. Demler
\\ ( http://arXiv.org/abs/cond-mat/0611426 , 3kb)
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Paper: quant-ph/0611174
Date: Thu, 16 Nov 2006 10:41:46 GMT (103kb)

Title: Controlled Creation of Spatial Superposition States for Single Atoms
Authors: K. Deasy, Th. Busch, Y. Niu, S. Gong, S. Jin and S. Nic Chormaic
\\
We present a method for the controlled and robust generation of spatial
superposition states of single atoms in micro-traps. Using a counter-intuitive
positioning sequence for the individual potentials and appropriately chosen
trapping frequencies, we show that it is possible to selectively create two
different orthogonal superposition states, which can in turn be used for
quantum information purposes.
\\ ( http://arXiv.org/abs/quant-ph/0611174 , 103kb)
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Paper: quant-ph/0611178
Date: Thu, 16 Nov 2006 12:52:21 GMT (431kb)

Title: Preparation and Determination of Spin-Polarized States in
Multi-Zeeman-sublevel Atoms
Authors: Bo Wang, Yanxu Han, Jintao Xiao, Xudong Yang, Chunhong Zhang, Hai
Wang, Min Xiao, and Kunchi Peng
Comments: 17pages, 4figures, Submit to Physical Review Letters
\\
We demonstrate a simple technique to prepare and determine the desired
internal quantum states in multi-Zeeman-sublevel atoms. By choosing appropriate
coupling and pumping laser beams, atoms can be easily prepared in a desired
Zeeman sublevel with high purity or in any chosen ground-state population
distributions. The population distributions or state purities of such prepared
atomic states can be determined by using a weak, circularly-polarized probe
beam due to differences in transition strengths among different Zeeman
sublevels. Preparing well-defined internal quantum states in
multi-Zeeman-sublevel atoms (or spin-polarized quantum-state engineering) will
be very important in demonstrating many interesting effects in quantum
information processing with multi-level atomic systems.
\\ ( http://arXiv.org/abs/quant-ph/0611178 , 431kb)
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Replaced papers:

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\\
Paper: cond-mat/0607463
replaced with revised version Thu, 9 Nov 2006 22:36:57 GMT (14kb)

Title: Quantum insulating states of F=2 cold atoms in optical lattices
Authors: Fei Zhou and Gordon W. Semenoff (UBC)
Comments: 4 pages, 1 figure included
Subj-class: Other
Journal-ref: Phys. Rev. Lett. 97, 180411 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0607463 , 14kb)
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\\
Paper: cond-mat/0610162
replaced with revised version Thu, 9 Nov 2006 23:56:15 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; references updated
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0610162 , 21kb)
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\\
Paper: cond-mat/0602437
replaced with revised version Mon, 13 Nov 2006 07:29:47 GMT (187kb)

Title: Phase diagrams of one-dimensional Bose-Fermi mixtures of ultra-cold
atoms
Authors: L. Mathey, D.-W. Wang
Comments: 16 pages, 8 figures, v3: minor changes
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0602437 , 187kb)
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\\
Paper: cond-mat/0603654
replaced with revised version Mon, 13 Nov 2006 08:27:29 GMT (463kb)

Title: Dynamical density-density correlations in the one-dimensional Bose gas
Authors: J.-S. Caux and P. Calabrese
Comments: 4 pages, 3 figures, published version
Subj-class: Statistical Mechanics; Atomic Physics
Journal-ref: Phys.Rev. A74 (2006) 031605
\\ ( http://arXiv.org/abs/cond-mat/0603654 , 463kb)
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\\
Paper: cond-mat/0603655
replaced with revised version Mon, 13 Nov 2006 17:54:47 GMT (863kb)

Title: Towards a Bose-Glass of ultracold atoms in a disordered crystal of light
Authors: L. Fallani, J. E. Lye, V. Guarrera, C. Fort, M. Inguscio
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0603655 , 863kb)
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\\
Paper: cond-mat/0605183
replaced with revised version Mon, 13 Nov 2006 10:21:41 GMT (345kb)

Title: Detecting phonons and persistent currents in toroidal Bose-Einstein
condensates by means of pattern formation
Authors: M. Modugno, C. Tozzo, F. Dalfovo
Comments: 4 pages, 4 figures; new figures, revised version to appear as a Rapid
Communication in Physical Review A
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0605183 , 345kb)
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\\
Paper: cond-mat/0601420
replaced with revised version Tue, 14 Nov 2006 19:17:57 GMT (827kb)

Title: Production of cold molecules via magnetically tunable Feshbach
resonances
Authors: Thorsten Koehler, Krzysztof Goral, Paul S. Julienne
Comments: 50 pages, 26 figures, to be published in Reviews of Modern Physics,
final version with updated references
Subj-class: Other; Atomic Physics
\\ ( http://arXiv.org/abs/cond-mat/0601420 , 827kb)
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\\
Paper: cond-mat/0607438
replaced with revised version Tue, 14 Nov 2006 10:04:32 GMT (157kb)

Title: Guided Quasicontinuous Atom Laser
Authors: William Guerin (LCFIO), Jean-F\'{e}lix Riou (LCFIO), John P. Gaebler
(LCFIO), Vincent Josse (LCFIO), Philippe Bouyer (LCFIO), Alain Aspect (LCFIO)
Comments: version published in Phys. Rev. Lett. 97, 200402 (2006)
Proxy: ccsd ccsd-00085308
Subj-class: Other; Atomic Physics
\\ ( http://arXiv.org/abs/cond-mat/0607438 , 157kb)
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\\
Paper: cond-mat/0611054
replaced with revised version Tue, 14 Nov 2006 12:52:38 GMT (439kb)

Title: Formation of molecules and entangled atomic pairs from atomic BEC due to
Feshbach resonance
Authors: Vladimir A. Yurovsky (Tel Aviv University)
Subj-class: Soft Condensed Matter
\\ ( http://arXiv.org/abs/cond-mat/0611054 , 439kb)
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\\
Paper: quant-ph/0602098
replaced with revised version Tue, 14 Nov 2006 05:41:24 GMT (20kb)

Title: On quantum phase crossovers in finite systems
Authors: Clare Dunning, Katrina E. Hibberd, Jon Links
Comments: 11 pages, 2 figures. Final version accepted for publication
Journal-ref: J Stat Mech: Theor. Exp. (2006) P11005
DOI: 10.1088/1742-5468/2006/11/P11005
\\ ( http://arXiv.org/abs/quant-ph/0602098 , 20kb)
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\\
Paper: quant-ph/0608158
replaced with revised version Tue, 14 Nov 2006 09:12:47 GMT (89kb)

Title: How much entanglement can be generated between two atoms by detecting
photons?
Authors: L. Lamata, J.J. Garcia-Ripoll, J.I. Cirac
PRL
\\ ( http://arXiv.org/abs/quant-ph/0608158 , 89kb)
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\\
Paper: cond-mat/0608355
replaced with revised version Wed, 15 Nov 2006 16:39:46 GMT (271kb)

Title: A Quantum Top Inside a Bose Josephson Junction
Authors: Ingrid Bausmerth, Uwe R. Fischer, Anna Posazhennikova
Comments: 4 pages of RevTex4, 4 figures; rewritten discussion and displayed new
results
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0608355 , 271kb)
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\\
Paper: cond-mat/0609063
replaced with revised version Wed, 15 Nov 2006 19:48:27 GMT (245kb)

Title: Sign-free stochastic mean-field approach to strongly correlated phases
of ultracold fermions
Authors: Olivier Juillet (LPCC)
Proxy: ccsd ccsd-00090944
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0609063 , 245kb)
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\\
Paper: quant-ph/0601038
replaced with revised version Wed, 15 Nov 2006 10:53:23 GMT (434kb)

Title: Generalized spin squeezing inequalities in $N$ qubit systems: theory and
experiment
Authors: J. K. Korbicz, O. G\"uhne, M. Lewenstein, H. Haeffner, C. F. Roos, and
R. Blatt
Journal-ref: Phys. Rev. A 74, 052319 (2006)
\\ ( http://arXiv.org/abs/quant-ph/0601038 , 434kb)
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\\
Paper: cond-mat/0610198
replaced with revised version Thu, 16 Nov 2006 09:43:01 GMT (174kb)

Title: Many-body dynamics of repulsively bound pairs of particles in a periodic
potential
Authors: David Petrosyan, Bernd Schmidt, James R. Anglin, Michael Fleischhauer
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0610198 , 174kb)
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\\
Paper: physics/0608083
replaced with revised version Thu, 16 Nov 2006 20:27:11 GMT (476kb)

Title: Atom interferometry in a moving guide
Authors: Saijun Wu, Edward J. Su, Mara Prentiss
Comments: 12 pages, 4 figures (Updated data with new figures)
Subj-class: Atomic Physics; Optics
\\ ( http://arXiv.org/abs/physics/0608083 , 476kb)
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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/
=========================================================================
Legal stuff: Unless stated otherwise, this e-mail represents only the
views of the sender and not the views of the University of Queensland
=========================================================================

Received on Mon Nov 20 2006 - 11:51:23 EST

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