# Matt's arXiv selection, Monday 15th May 2006.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Mon, 15 May 2006 10:28:53 +1000 (EST)

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

Lots of interesting papers this week.

http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/

The abstracts:

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Paper: cond-mat/0605138
Date: Fri, 5 May 2006 12:40:09 GMT (52kb)

Title: Landau functions for non-interacting bosons
Authors: Andreas Sinner, Florian Schuetz, and Peter Kopietz
Subj-class: Statistical Mechanics
\\
We define and calculate the Landau functions and the associated order
parameter probability distributions for Bose-Einstein condensation (BEC) and
spontaneous symmetry breaking (SSB) of non-interacting bosons within a
canonical ensemble. We show that even for finite clusters consisting of N >= 2
bosons there is an unambiguously defined critical temperature where the Landau
function continuously develops minima at a finite value of the relevant order
parameter. For infinite systems BEC and SSB are described by the same Landau
function whose shape exhibits a rather complicated dependence on the
dimensionality and on the form of the external potential.
\\ ( http://arXiv.org/abs/cond-mat/0605138 , 52kb)
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Paper: cond-mat/0605140
Date: Fri, 5 May 2006 12:56:13 GMT (37kb)

Title: Phase separations of bosonic mixtures in optical lattices from
macroscopic to microscopic scales
Authors: Ofir E. Alon, Alexej I. Streltsov and Lorenz S. Cederbaum
Subj-class: Other
\\
Mixtures of cold bosonic atoms in optical lattices undergo phase separations
on different length scales with increasing inter-species repulsion. As a
general rule, the stronger the intra-species interactions, the shorter is this
length scale. The wealth of phenomena is documented by illustrative examples on
both superfluids and Mott-insulators.
\\ ( http://arXiv.org/abs/cond-mat/0605140 , 37kb)
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Paper: cond-mat/0605143
Date: Fri, 5 May 2006 15:11:25 GMT (68kb)

Title: Classification of zero-energy resonances by dissociation of Feshbach
molecules
Authors: Thomas M. Hanna, Krzysztof Goral, Emilia Witkowska, Thorsten Koehler
Comments: 10 pages, 5 eps figures
Subj-class: Other
\\
We study the dissociation of Feshbach molecules by a magnetic field sweep
across a zero-energy resonance. In the limit of an instantaneous magnetic field
change, the distribution of atomic kinetic energy can have a peak indicating
dominance of the molecular closed-channel spin configuration over the entrance
channel. The extent of this dominance influences physical properties such as
stability with respect to collisions, and so the readily measurable presence or
absence of the corresponding peak provides a practical method of classifying
zero-energy resonances. Currently achievable ramp speeds, e.g. those
demonstrated by Duerr et al. [Phys. Rev. A 70, 031601 (2005)], are fast enough
to provide magnetic field changes that may be interpreted as instantaneous. We
study the transition from sudden magnetic field changes to asymptotically wide,
linear ramps. In the latter limit, the predicted form of the atomic kinetic
energy distribution is independent of the specific implementation of the
two-body physics, provided that the near-resonant scattering properties are
properly accounted for.
\\ ( http://arXiv.org/abs/cond-mat/0605143 , 68kb)
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Paper: cond-mat/0605148
Date: Fri, 5 May 2006 16:18:15 GMT (8kb)

Title: Bose-Einstein condensation and entanglement in magnetic systems
Authors: Mucio A. Continentino
Subj-class: Strongly Correlated Electrons; Statistical Mechanics
\\
We present a study of magnetic field induced quantum phase transitions in
insulating systems. A generalized scaling theory is used to obtain the
temperature dependence of several physical quantities along the quantum
critical trajectory ($H=H_{C}$, $T\to0$) where $H$ is a longitudinal external
magnetic field and $H_{C}$ the critical value at which the transition occurs.
We consider transitions from a spin liquid at a critical field $H_{C1}$ and
from a fully polarized paramagnet, at $H_{C2}$, into phases with long range
order in the transverse components. The transitions at $H_{C1}$ and $H_{C2}$
can be viewed as Bose-Einstein condensations of magnons which however belong to
different universality classes since they have different values of the dynamic
critical exponent $z$. Finally, we use that the magnetic susceptibility is an
entanglement witness to discuss how this type of correlation sets in as the
system approaches the quantum critical point along the critical trajectory,
$H=H_{C2}$, $T\to0$.
\\ ( http://arXiv.org/abs/cond-mat/0605148 , 8kb)
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Paper: quant-ph/0605055
Date: Fri, 5 May 2006 14:06:40 GMT (53kb)

Title: Atom interferometry
Authors: Alain Miffre (LCAR), Marion Jacquey (LCAR), Matthias B\"{u}chner
(LCAR), G\'{e}rard Tr\'{e}nec (LCAR), Jacques Vigu\'{e} (LCAR)
Comments: submitted to Physica Scripta as a Comment on Atomic Molecular and
Optical Physics
Proxy: ccsd ccsd-00023896
\\
In this paper, we present a brief overview of atom interferometry. This field
of research has developed very rapidly since 1991. Atom and light wave
interferometers present some similarities but there are very important
differences in the tools used to manipulate these two types of waves. Moreover,
the sensitivity of atomic waves and light waves to their environment is very
different. Atom interferometry has already been used for a large variety of
studies: measurements of atomic properties and of inertial effects
observation of quantum decoherence, etc. We review the techniques used for a
coherent manipulation of atomic waves and the main applications of atom
interferometers.
\\ ( http://arXiv.org/abs/quant-ph/0605055 , 53kb)
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Paper: quant-ph/0605059
Date: Fri, 5 May 2006 16:12:28 GMT (216kb)

Title: Creation of macroscopic superpositions of flow states with Bose-Einstein
condensates
Authors: Jacob Dunningham and David Hallwood
\\
We present a straightforward scheme for creating macroscopic superpositions
of different superfluid flow states of Bose-Einstein condensates trapped in
optical lattices. This scheme has the great advantage that all the techniques
required are achievable with current experiments. Furthermore, the relative
difficulty of creating cats scales favorably with the size of the cat. This
means that this scheme may be well-suited to creating superpositions involving
large numbers of particles. Such states may have interesting technological
applications such as making quantum-limited measurements of angular momentum.
\\ ( http://arXiv.org/abs/quant-ph/0605059 , 216kb)
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Paper: cond-mat/0605154
Date: Fri, 5 May 2006 22:23:19 GMT (17kb)

Title: Fractionalization in Bosonic Extended Hubbard Models : Emergence of
Artificial Photons in an Optical Lattice
Authors: Sumanta Tewari, V. W. Scarola, T. Senthil, S. Das Sarma
Comments: 4+ pages, 1 eps figure
Subj-class: Strongly Correlated Electrons
\\
We establish the theoretical feasibility of direct analog simulation of the
compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We
discuss the realizability of various fractionalized topological phases in
extended Bose-Hubbard models in several optical lattice geometries. We predict
the testable signatures of the emergent U(1) Coulomb phase in noise correlation
measurements, thus suggesting the possible emergence of artificial light in
optical lattices.
\\ ( http://arXiv.org/abs/cond-mat/0605154 , 17kb)
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Paper: cond-mat/0605163
Date: Sat, 6 May 2006 15:06:55 GMT (156kb)

Title: Mean-field phase diagram of disordered bosons in a lattice at non-zero
temperature
Authors: K.V.Krutitsky, A.Pelster and R.Graham
Subj-class: Other; Disordered Systems and Neural Networks
\\
Bosons in a periodic lattice with on-site disorder at low but non-zero
temperature are considered within a mean-field theory. We show that, not only
at vanishing but also at non-zero temperature, both the Mott-insulator and the
Bose-glass phase are unambiguously distinguished by their density of states at
small energies. We obtain the phase diagram of these phases as well as the
superfluid.
\\ ( http://arXiv.org/abs/cond-mat/0605163 , 156kb)
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Paper: cond-mat/0605169
Date: Sun, 7 May 2006 15:04:33 GMT (248kb)

Title: Fermion pairing with spin-density imbalance in an optical lattice
Authors: T. Koponen, J. Kinnunen, J.-P. Martikainen, L.M. Jensen, and P. Torma
Subj-class: Superconductivity; Materials Science
\\
We consider pairing in a two-component atomic Fermi gas, in a
three-dimensional optical lattice, when the components have unequal densities,
i.e. the gas is polarized. We show that a superfluid where the translational
symmetry is broken by a finite Cooper pair momentum, namely an FFLO-type state,
minimizes the Helmholtz free energy of the system. We demonstrate that such a
state is clearly visible in the observable momentum distribution of the atoms,
and analyze the dependence of the order parameter and the momentum distribution
on the filling fraction and the interaction strength.
\\ ( http://arXiv.org/abs/cond-mat/0605169 , 248kb)
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Paper: cond-mat/0605180
Date: Mon, 8 May 2006 08:00:49 GMT (913kb)

Title: Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas
Authors: Y. H. Pong, C. K. Law
Comments: 14 pages, 4 figures, submitted to Phys. Rev. A
Subj-class: Other
\\
We examine the basic mode structure of atomic Cooper pairs in an
inhomogeneous Fermi gas. Based on the properties of Bogoliubov quasi-particle
vacuum, the single particle density matrix and the anomalous density matrix
share the same set of eigenfunctions. These eigenfunctions correspond to
natural pairing orbits associated with the BCS ground state. We investigate
these orbits for a Fermi gas in a spherical harmonic trap, and construct the
wave function of a Cooper pair in the form of Schmidt decomposition. The issue
of spatial quantum entanglement between constituent atoms in a pair is
\\ ( http://arXiv.org/abs/cond-mat/0605180 , 913kb)
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Paper: cond-mat/0605183
Date: Mon, 8 May 2006 08:57:36 GMT (508kb)

Title: Detecting phonons and persistent currents in toroidal Bose-Einstein
condensates by means of pattern formation
Authors: M. Modugno, C. Tozzo, F. Dalfovo
Subj-class: Other
\\
We theoretically investigate the dynamic properties of a Bose-Einstein
condensate in a toroidal trap. A periodic modulation of the transverse
confinement is shown to produce a density pattern due to parametric
amplification of phonon pairs. By imaging the density distribution after free
expansion one obtains i) a precise determination of the Bogoliubov spectrum and
ii) a sensitive detection of quantized circulation in the torus. The parametric
amplification is also sensitive to thermal and quantum fluctuations.
\\ ( http://arXiv.org/abs/cond-mat/0605183 , 508kb)
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Paper: cond-mat/0605184
Date: Mon, 8 May 2006 10:11:07 GMT (832kb)

Title: A Mott state of molecules
Authors: T. Volz, N. Syassen, D. M. Bauer, E. Hansis, S. D\"urr, G. Rempe
Subj-class: Statistical Mechanics
\\
Mott insulators of ultracold gases in optical lattices are of great interest,
because they represent strongly correlated many-body systems with quantum
states that cannot be described as simple products of single-particle wave
functions. These systems bear a great potential for applications in quantum
simulations and quantum information processing, in particular when using
particles with a long-range dipole-dipole interaction, such as polar molecules.
Here we show the realization of a Mott state of molecules. The molecules are
produced from an atomic Mott insulator with a density profile chosen such that
the central region of the gas contains two atoms per lattice site. A Feshbach
resonance is used to associate the atom pairs to molecules. Remaining atoms can
be removed with blast light. In order to show that the resulting state is a
molecular Mott state, the molecules are dissociated and the lattice depth is
reduced. This restores phase coherence which is seen in time-of-flight images.
\\ ( http://arXiv.org/abs/cond-mat/0605184 , 832kb)
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Paper: cond-mat/0605196
Date: Mon, 8 May 2006 14:33:01 GMT (614kb)

Title: Repulsively bound atom pairs in an optical lattice
Authors: K. Winkler, G. Thalhammer, F. Lang, R. Grimm, J. Hecker Denschlag, A.
J. Daley, A. Kantian, H. P. Buechler, P. Zoller
Subj-class: Other
\\
Throughout physics, stable composite objects are usually formed via
attractive forces, which allow the constituents to lower their energy by
binding together. Repulsive forces separate particles in free space. However,
in a structured environment such as a periodic potential and in the absence of
dissipation, stable composite objects can exist even for repulsive
interactions. Here we report on the first observation of such an exotic bound
state, comprised of a pair of ultracold atoms in an optical lattice. Consistent
with our theoretical analysis, these repulsively bound pairs exhibit long
lifetimes, even under collisions with one another. Signatures of the pairs are
also recognised in the characteristic momentum distribution and through
spectroscopic measurements. There is no analogue in traditional condensed
matter systems of such repulsively bound pairs, due to the presence of strong
decay channels. These results exemplify on a new level the strong
correspondence between the optical lattice physics of ultracold bosonic atoms
and the Bose-Hubbard model, a correspondence which is vital for future
applications of these systems to the study of strongly correlated condensed
matter systems and to quantum information.
\\ ( http://arXiv.org/abs/cond-mat/0605196 , 614kb)
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Paper: cond-mat/0605197
Date: Mon, 8 May 2006 15:07:06 GMT (163kb)

Title: Calogero-Sutherland-Lieb-Liniger gas in one-dimensional cold atoms
Authors: Yue Yu
Subj-class: Other; Statistical Mechanics
\\
We study an array of cigar-like Bose atom condensates confined in a cylinder
and examine the competition between the dipole-dipole and the short range
interactions. The system is effectively reduced to a one-dimensional boson one
with a contact and inverse square interactions. We call this system the
Calogero-Sutherland-Lieb-Liniger gas. The universal properties of the ground
state are analyzed by the renormalization group theory. By using the
bosonization techniques to the excluson gas, we calculate the non-universal
exponent depending on the microscopic parameters. This exponent may be
experimentally measurable.
\\ ( http://arXiv.org/abs/cond-mat/0605197 , 163kb)
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Paper: cond-mat/0605198
Date: Mon, 8 May 2006 15:34:40 GMT (736kb)

Title: Cooling toolbox for atoms in optical lattices
Authors: M. Popp, J.-J. Garcia-Ripoll, K. G. H. Vollbrecht and J. I. Cirac
Subj-class: Other
\\
We propose and analyze several schemes for cooling bosonic and fermionic
atoms in an optical lattice potential close to the ground state of the
no-tunnelling regime. Some of the protocols rely on the concept of algorithmic
cooling, which combines occupation number filtering with ideas from ensemble
quantum computation. We also design algorithms that create an ensemble of
defect-free quantum registers. We study the efficiency of our protocols for
realistic temperatures and in the presence of a harmonic confinement. We also
propose an incoherent physical implementation of filtering which can be
operated in a continuous way.
\\ ( http://arXiv.org/abs/cond-mat/0605198 , 736kb)
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Paper: cond-mat/0602620
replaced with revised version Mon, 8 May 2006 10:42:41 GMT (18kb)

Title: Composite-fermion description of rotating Bose gases at low angular
momenta
Authors: Nicolay Korslund and Susanne Viefers
Comments: 7 pages (RevTeX), 1 figure. Slightly revised version (accepted for
publication in Phys Rev A)
Report-no: OSLO-TP 1-06
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\ ( http://arXiv.org/abs/cond-mat/0602620 , 18kb)
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Paper: cond-mat/0603424
replaced with revised version Mon, 8 May 2006 16:17:57 GMT (331kb)

Title: Superfluid Dynamics of a Bose-Einstein Condensate in a One Dimensional
Optical Super-Lattice
Authors: Aranya B Bhattacherjee
Subj-class: Statistical Mechanics
\\ ( http://arXiv.org/abs/cond-mat/0603424 , 331kb)
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Paper: cond-mat/0604424
replaced with revised version Mon, 8 May 2006 07:28:29 GMT (164kb)

Title: Non-BCS superfluidity in trapped ultracold Fermi gases
Authors: L. M. Jensen, J. Kinnunen, and P. Torma
Subj-class: Strongly Correlated Electrons; Other
\\ ( http://arXiv.org/abs/cond-mat/0604424 , 164kb)
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Paper: cond-mat/0604464
replaced with revised version Mon, 8 May 2006 14:49:56 GMT (119kb)

Title: Quantum theory of an atom laser originating from a Bose-Einstein
condensate or a Fermi gas in the presence of gravity
Authors: Tobias Kramer and Mirta Rodriguez
Comments: 13 pages, 8 figures, slightly expanded version
Subj-class: Other; Atomic Physics
\\ ( http://arXiv.org/abs/cond-mat/0604464 , 119kb)
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Paper: quant-ph/0605075
Date: Mon, 8 May 2006 11:51:59 GMT (340kb)

Title: Cavity-QED entangled photon source based on two truncated Rabi
oscillations
Authors: R. Garcia-Maraver, K. Eckert, R. Corbalan, and J. Mompart
Comments: 18 pages, 9 figures; submitted for the "Optical Quantum Information
Science Special Issue" of JOSA B
\\
We discuss a cavity-QED scheme to deterministically generate entangled
photons pairs by using a three-level atom successively coupled to two single
longitudinal mode high-Q cavities presenting polarization degeneracy. The first
cavity is prepared in a well defined Fock state with two photons with opposite
circular polarizations while the second cavity remains in the vacuum state. A
half-of-a-resonant Rabi oscillation in each cavity transfers one photon from
the first to the second cavity, leaving the photons entangled in their
polarization degree of freedom. The feasibility of this implementation and some
practical considerations are discussed for both, microwave and optical regimes.
In particular, Monte Carlo wave function simulations have been performed with
state-of-the-art parameter values to evaluate the success probability of the
cavity-QED source in producing entangled photon pairs as well as its
entanglement capability.
\\ ( http://arXiv.org/abs/quant-ph/0605075 , 340kb)
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Paper: physics/0605052
Date: Sat, 6 May 2006 04:36:30 GMT (420kb)

Title: Cooling in reduced period optical lattices: non-zero Raman detuning
Authors: V. S. Malinovsky and P. R. Berman
Subj-class: Atomic Physics; General Physics
\\
In a previous paper [Phys. Rev. A 72, 033415 (2005)], it was shown that
sub-Doppler cooling occurs in a standing-wave Raman scheme (SWRS) that can lead
to reduced period optical lattices. These calculations are extended to allow
for non-zero detuning of the Raman transitions. New physical phenomena are
encountered, including cooling to non-zero velocities, combinations of Sisyphus
and "corkscrew" polarization cooling, and somewhat unusual origins of the
friction force. The calculations are carried out in a semi-classical
approximation and a dressed state picture is introduced to aid in the
interpretation of the results.
\\ ( http://arXiv.org/abs/physics/0605052 , 420kb)
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Paper: cond-mat/0605206
Date: Tue, 9 May 2006 02:58:58 GMT (96kb)

Title: Stabilization of BEC droplet in free space by feedback control of
interatomic interaction
Authors: Hiroki Saito and Masahito Ueda
Subj-class: Other
\\
A self-trapped Bose-Einstein condensate in three-dimensional free space is
shown to be stabilized by feedback control of the interatomic interaction
through nondestructive measurement of the condensate's peak column density. The
stability is found to be robust against poor resolution and experimental errors
in the measurement.
\\ ( http://arXiv.org/abs/cond-mat/0605206 , 96kb)
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Paper: cond-mat/0605207
Date: Mon, 8 May 2006 18:12:07 GMT (42kb)

Title: Entanglement entropy and entanglement witnesses in models of strongly
interacting low-dimensional fermions
Authors: V. V. Fran\c{c}a and K. Capelle
Subj-class: Strongly Correlated Electrons; Statistical Mechanics
\\
We investigate the behaviour of an entanglement measure (the local von Neuman
entropy ${\cal E}$) and an entanglement witness (the spin susceptibility
$\chi$) in models of strongly correlated fermions with metallic, insulating and
superconducting phases. ${\cal E}$ changes drastically at quantum critical
points, such as the Mott metal-insulator transition, but also at the smoother
crossover from the BCS to the Bose-Einstein regime of paired particles.
Nontrivial dependence of ${\cal E}$ on the system parameters is observed
throughout the phase diagram, even away from critical points and lines, but
${\cal E}$ is found not to be a state function in the thermodynamic sense.
Hilbert space restrictions can lead to counterintuitive behaviour of ${\cal E}$. The spin susceptibility is shown to be a faithfull entanglement marker,
but its dependence on the nature of the underlying particle-particle
interactions is nontrivial. The opening of spin gaps in antiferromagnetic
insulators is numerically shown to be associated with enhanced entanglement.
\\ ( http://arXiv.org/abs/cond-mat/0605207 , 42kb)
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Paper: cond-mat/0605218
Date: Tue, 9 May 2006 06:28:12 GMT (42kb)

Title: Supersolid phases in the one dimensional extended soft core Bosonic
Hubbard model
Authors: G.G. Batrouni, F. Hebert, R.T. Scalettar
Subj-class: Superconductivity; Statistical Mechanics
\\
We present results of Quantum Monte Carlo simulations for the soft core
extended bosonic Hubbard model in one dimension. By studying the superfluid
density, the compressibility and the structure factor, we show that, contrary
to previous claims, supersolid phases are present, similar to those recently
shown to exist in two dimensions. We find the dynamic critical exponent z=1 for
the insulator-superfluid transition and z=2 for the insulator-supersolid
transition. The mechanism behind this difference is discussed. The simultaneous
presence of two types of quasi long range order results in two soliton-like
dips in the excitation spectrum.
\\ ( http://arXiv.org/abs/cond-mat/0605218 , 42kb)
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Paper: cond-mat/0605005
replaced with revised version Tue, 9 May 2006 18:52:15 GMT (49kb)

Title: Phase Transition in Imbalanced Fermion Superfluids
Authors: Heron Caldas
Comments: This is an invited contribution to a book titled "Pairing beyond BCS
Theory in Fermionic Systems" (Mark Alford, John Clark and Armen Sedrakian,
references
Subj-class: Superconductivity; Strongly Correlated Electrons
\\ ( http://arXiv.org/abs/cond-mat/0605005 , 49kb)
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Paper: cond-mat/0605258
Date: Wed, 10 May 2006 10:56:53 GMT (751kb)

Title: Direct Observation of the Superfluid Phase Transition in Ultracold Fermi
Gases
Authors: Martin W. Zwierlein, Christian H. Schunck, Andre Schirotzek, and
Wolfgang Ketterle
Comments: 16 pages (incl. Supplemental Material), 5 figures
Subj-class: Superconductivity; Strongly Correlated Electrons
\\
Water freezes into ice, atomic spins spontaneously align in a magnet, liquid
helium becomes superfluid: Phase transitions are dramatic phenomena. However,
despite the drastic change in the system's behaviour, observing the transition
can sometimes be subtle. The hallmark of Bose-Einstein condensation (BEC) and
superfluidity in trapped, weakly interacting Bose gases is the sudden
appearance of a dense central core inside a thermal cloud. In strongly
interacting gases, such as the recently observed fermionic superfluids, this
clear separation between the superfluid and the normal parts of the cloud is no
longer given. Condensates of fermion pairs could be detected only using
magnetic field sweeps into the weakly interacting regime. The quantitative
description of these sweeps presents a major theoretical challenge. Here we
demonstrate that the superfluid phase transition can be directly observed by
sudden changes in the shape of the clouds, in complete analogy to the case of
weakly interacting Bose gases. By preparing unequal mixtures of the two spin
components involved in the pairing, we greatly enhance the contrast between the
superfluid core and the normal component. Furthermore, the non-interacting
wings of excess atoms serve as a direct and reliable thermometer. Even in the
normal state, strong interactions significantly deform the density profile of
the majority spin component. We show that it is these interactions which drive
the normal-to-superfluid transition at the critical population imbalance of
70(5)%.
\\ ( http://arXiv.org/abs/cond-mat/0605258 , 751kb)
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Paper: cond-mat/0605261
Date: Wed, 10 May 2006 11:11:16 GMT (32kb)

Title: Transmission of matter wave solitons through nonlinear traps and
barriers
Authors: Josselin Garnier, Fatkhulla Abdullaev
Subj-class: Other
\\
The transmissions of matter wave solitons through linear and nonlinear
inhomogeneities induced by the spatial variations of the trap and the
scattering length in Bose-Einstein condensates are investigated. New phenomena,
such as the enhanced transmission of a soliton through a linear trap by a
modulation of the scattering length, are exhibited. The theory is based on the
perturbed Inverse Scattering Transform for solitons, and we show that radiation
effects are important. Numerical simulations of the Gross-Pitaevskii equation
confirm the theoretical predictions.
\\ ( http://arXiv.org/abs/cond-mat/0605261 , 32kb)
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Paper: cond-mat/0605271
Date: Wed, 10 May 2006 14:41:57 GMT (291kb)

Title: Non-Linear Beam Splitter in Bose-Einstein Condensate Interferometers
Authors: L. Pezze', A. Smerzi, G.P. Berman, A.R. Bishop, and L.A. Collins
Comments: draft, 19 pages, 10 figures
Subj-class: Materials Science
\\
A beam splitter is an important component of an atomic/optical Mach-Zehnder
interferometer. Here we study a Bose Einstein Condensate beam splitter,
realized with a double well potential of tunable height. We analyze how the
sensitivity of a Mach Zehnder interferometer is degraded by the non-linear
particle-particle interaction during the splitting dynamics. We distinguish
three regimes, Rabi, Josephson and Fock, and associate to them a different
scaling of the phase sensitivity with the total number of particles.
\\ ( http://arXiv.org/abs/cond-mat/0605271 , 291kb)
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Paper: cond-mat/0510624
replaced with revised version Tue, 9 May 2006 22:58:13 GMT (496kb)

Title: The role of interactions, tunneling and harmonic confinement on the
Authors: Ana Maria Rey, Guido Pupillo, and J. V. Porto
Comments: 9 pages and 6 figures. Two typos in Sec.IIIA were corrected and some
references were updated
Subj-class: Statistical Mechanics
Journal-ref: Phys. Rev. A 73, 023608 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0510624 , 496kb)
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Paper: cond-mat/0511641
replaced with revised version Wed, 10 May 2006 17:18:10 GMT (40kb)

Title: Quantum criticality of a Fermi gas with a spherical dispersion minimum
Authors: Kun Yang and Subir Sachdev
(v3) published version with correction to lifetime result
Subj-class: Strongly Correlated Electrons; Superconductivity
Journal-ref: Physical Review Letters 96, 187001 (2006)
DOI: 10.1103/PhysRevLett.96.187001
\\ ( http://arXiv.org/abs/cond-mat/0511641 , 40kb)
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Paper: quant-ph/0604074
replaced with revised version Wed, 10 May 2006 16:50:57 GMT (20kb)

Title: Thermal limitation of far-field matter-wave interference
Authors: Klaus Hornberger
Comments: 8 pages, 2 figures; published version
Journal-ref: Phys. Rev. A 73, 052102 (2006)
DOI: 10.1103/PhysRevA.73.052102
\\ ( http://arXiv.org/abs/quant-ph/0604074 , 20kb)
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Paper: cond-mat/0605283
Date: Wed, 10 May 2006 20:01:45 GMT (543kb)

Title: Matter-wave solitons in radially periodic potentials
Authors: Bakhtiyor B. Baizakov, Boris A. Malomed, and Mario Salerno
Subj-class: Other
\\
We investigate two-dimensional (2D) states of Bose-Einstein condensates (BEC)
with self-attraction or self-repulsion, trapped in an axially symmetric
optical-lattice potential periodic along the radius. Unlike previously studied
2D models with Bessel lattices, no localized states exist in the linear limit
of the present model, hence all localized states are truly nonlinear ones. We
consider the states trapped in the central potential well, and in remote
circular troughs. In both cases, a new species, in the form of \textit{radial
gap solitons}, are found in the repulsive model (the gap soliton trapped in a
circular trough may additionally support stable dark-soliton pairs). In remote
troughs, stable localized states may assume a ring-like shape, or shrink into
strongly localized solitons. The existence of stable annular states, both
azimuthally uniform and weakly modulated ones, is corroborated by simulations
of the corresponding Gross-Pitaevskii equation. Dynamics of strongly localized
solitons circulating in the troughs is also studied. While the solitons with
sufficiently small velocities are stable, fast solitons gradually decay, due to
the leakage of matter into the adjacent trough under the action of the
centrifugal force. Collisions between solitons are investigated too. Head-on
collisions of in-phase solitons lead to the collapse; $\pi$-out of phase
solitons bounce many times, but eventually merge into a single soliton without
collapsing. The proposed setting may also be realized in terms of spatial
solitons in photonic-crystal fibers with a radial structure.
\\ ( http://arXiv.org/abs/cond-mat/0605283 , 543kb)
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\\
Paper: cond-mat/0605291
Date: Thu, 11 May 2006 06:55:25 GMT (269kb)

Title: Berezinskii-Kosterlitz-Thouless Crossover in a Trapped Atomic Gas
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: accepted for publication in Nature
Proxy: ccsd ccsd-00067716
Subj-class: Other
\\
Any state of matter is classified according to its order, and the kind of
order a physical system can posses is profoundly affected by its
dimensionality. Conventional long-range order, like in a ferromagnet or a
crystal, is common in three-dimensional (3D) systems at low temperature.
However, in two-dimensional (2D) systems with a continuous symmetry, true
long-range order is destroyed by thermal fluctuations at any finite
temperature. Consequently, in contrast to the 3D case, a uniform 2D fluid of
identical bosons cannot undergo Bose-Einstein condensation. Nevertheless, it
can form a "quasi-condensate" and become superfluid below a finite critical
temperature. The Berezinskii-Kosterlitz-Thouless (BKT) theory associates this
phase transition with the emergence of a topological order, resulting from the
pairing of vortices with opposite circulations. Above the critical temperature,
proliferation of unbound vortices is expected. Here we report the observation
of a BKT-type crossover in a trapped quantum degenerate gas of rubidium atoms.
Using a matter wave heterodyning technique, we observe both the long-wavelength
fluctuations of the quasi-condensate phase and the free vortices. 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 proliferation of free vortices. Our results provide
direct experimental evidence for the microscopic mechanism underlying the BKT
theory, and raise new questions regarding coherence and superfluidity in
mesoscopic systems.
\\ ( http://arXiv.org/abs/cond-mat/0605291 , 269kb)
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\\
Paper: cond-mat/0605302
Date: Thu, 11 May 2006 13:49:52 GMT (200kb)

Title: Transport of Atom Packets in a Train of Ioffe-Pritchard Traps
Authors: Thierry Lahaye (LKB - Lhomond), Gael Reinaudi (LKB - Lhomond),
Zhaoying Wang (LKB - Lhomond), Antoine Couvert (LKB - Lhomond), David
Gu\'{e}ry-Odelin (LKB - Lhomond)
Proxy: ccsd ccsd-00068349
Subj-class: Other
\\
We demonstrate transport and evaporative cooling of several atomic clouds in
a chain of magnetic Ioffe-Pritchard traps moving at a low speed ($<1$~m/s). The
trapping scheme relies on the use of a magnetic guide for transverse
confinement and of magnets fixed on a conveyor belt for longitudinal trapping.
This experiment introduces a new approach for parallelizing the production of
Bose-Einstein condensates as well as for the realization of a continuous atom
laser.
\\ ( http://arXiv.org/abs/cond-mat/0605302 , 200kb)
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\\
Paper: cond-mat/0510635
replaced with revised version Thu, 11 May 2006 15:40:57 GMT (609kb)

Title: Integrable models for asymmetric Fermi superfluids: Emergence of a new
exotic pairing phase
Authors: J. Dukelsky, G. Ortiz, S.M.A. Rombouts and K. Van Houcke
Comments: Revised version accepted for publication
Subj-class: Other; Superconductivity
Journal-ref: Phys. Rev. Lett 96, 180404 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0510635 , 609kb)
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\\
Paper: cond-mat/0601184
replaced with revised version Thu, 11 May 2006 01:02:35 GMT (726kb)

Title: Observation of Strong Quantum Depletion in a Gaseous Bose-Einstein
Condensate
Authors: K. Xu, Y. Liu, D.E. Miller, J.K. Chin, W. Setiawan and W. Ketterle
Comments: Replaced with accepted version in PRL
Subj-class: Other
Journal-ref: Phys. Rev. Lett. 96, 180405 (2006)
DOI: 10.1103/PhysRevLett.96.180405
\\ ( http://arXiv.org/abs/cond-mat/0601184 , 726kb)
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\\
Paper: cond-mat/0602278
replaced with revised version Wed, 10 May 2006 20:57:41 GMT (168kb)

Title: Vortex-Peierls States in Optical Lattices
Authors: A.A. Burkov, Eugene Demler
Comments: 4 pages, 4 figures. Published version
Subj-class: Strongly Correlated Electrons; Superconductivity
Journal-ref: Physical Review Letters 96, 180406 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0602278 , 168kb)
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\\
Paper: cond-mat/0604139
replaced with revised version Thu, 11 May 2006 13:44:30 GMT (599kb)

Title: Bose-Fermi Mixtures in a Three-dimensional Optical Lattice
Authors: Kenneth G\"unter, Thilo St\"oferle, Henning Moritz, Michael K\"ohl,
Tilman Esslinger
Subj-class: Strongly Correlated Electrons
Journal-ref: Phys. Rev. Lett. 96, 180402 (2006)
DOI: 10.1103/PhysRevLett.96.180402
\\ ( http://arXiv.org/abs/cond-mat/0604139 , 599kb)
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\\
Paper: physics/0605092
Date: Thu, 11 May 2006 10:07:49 GMT (269kb)

Title: Diffuse reflection of a Bose-Einstein condensate from a rough evanescent
wave mirror
Authors: Helene Perrin, Yves Colombe, Brigitte Mercier, Vincent Lorent, and
Carsten Henkel
Comments: submitted to J Phys B, 10 pages, 6 figures
Subj-class: Atomic Physics; Optics
\\
We present experimental results showing the diffuse reflection of a
Bose-Einstein condensate from a rough mirror, consisting of a dielectric
substrate supporting a blue-detuned evanescent wave. The scattering is
anisotropic, more pronounced in the direction of the surface propagation of the
evanescent wave. These results agree very well with theoretical predictions.
\\ ( http://arXiv.org/abs/physics/0605092 , 269kb)
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--
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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/
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Received on Mon May 15 2006 - 10:28:53 EST

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