Matt's arXiv selection: week ending 21 December 2007.

From: Matthew Davis <>
Date: Sat, 22 Dec 2007 07:03:22 +1000

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

Hi everyone,

I'm very pleased to have achieved my goal and have this week's mailing ready
early: it's been a long time since that happened! The next mailing will be
early in the new year.

This week sees 28 new preprints and 10 replacements. Merry Christmas to everybody!

Date: Thu, 13 Dec 2007 23:16:50 GMT (367kb)

Title: Bose-Einstein Condensation in Magnetic Insulators
Authors: T. Giamarchi, Ch. R\"uegg, O. Tchernyshyov
Categories: cond-mat.str-el
Comments: 17 pages, 3 figures
   The elementary excitations in antiferromagnets are magnons, quasiparticles
with integer spin and Bose statistics. In an experiment their density is
controlled efficiently by an applied magnetic field and can be made finite to
cause the formation of a Bose-Einstein condensate (BEC). Studies of magnon
condensation in a growing number of magnetic materials provide a unique window
into an exciting world of quantum phase transitions (QPT) and exotic quantum
\\ ( , 367kb)
Date: Fri, 14 Dec 2007 17:19:16 GMT (192kb)

Title: New type of Bose-Einstein condensation of cold atoms with effective
   spin-orbit interactions
Authors: Tudor Stanescu and Victor Galitski
Categories: cond-mat.other cond-mat.stat-mech
Comments: 4 pages, 2 color figures
   We consider a many-body system of multi-level Bose-atoms moving in the
presence of spatially modulated laser fields. The light field couples three
hyperfine ground states of an atom to an excited level, leading to the
appearance of a pair of degenerate dark states. The effective many-body
Hamiltonian describes a system of pseudo-spin-1/2 bosons with emergent
spin-orbit interactions, which couple the momentum and the internal pseudo-spin
degree of freedom. The corresponding band structure is generally anisotropic
and contains two minima at finite momenta. At low temperatures, the many-body
system condenses into the double-degenerate single-particle ground states,
leading to a new type of Bose-Einstein condensate. We obtain the corresponding
many-body wave-function describing a condensate of "left-" and "right-moving"
bosons. We also show that by fine-tuning the parameters of the laser field, one
can obtain a bosonic version of the spin-orbit coupled Rashba model. In this
symmetric case, the degeneracy of the ground state is very large, which may
lead to phases with non-trivial topological properties. The predicted states
can be observed experimentally via time-of-flight imaging, which will show
characteristic double-peak or ring-like structures in momentum distribution.
\\ ( , 192kb)
Date: Fri, 14 Dec 2007 16:01:09 GMT (16kb)

Title: A variational Jastrow coupled-cluster theory of quantum many-body
Authors: Y. Xian
Categories: cond-mat.str-el
   We study many-body correlations in the ground states of a general quantum
system of bosons or fermions by including an additional Jastrow function in our
ecently proposed variational coupled-cluster method. Our approach combines the
dvantages of state-dependent correlations in the coupled-cluster theory and of
strong, short-ranged correlations of the Jastrow function. We apply a
generalized linked-cluster expansion for the Jastrow wavefunction and provide
detailed analysis for practical evaluation of Hamiltonian expectation value as
an energy functional of the Jastrow function and the bare density-distribution
functions introduced and calculated in our earlier publications; a simple,
first-order energy functional is derived and detailed formulas for higher-order
contributions are provided. Our energy functional does not suffer the
divergence as in most coupled-cluster calculations when applying to
Hamiltonians with hardcore potentials. We also discuss relations between our
energy functional and the energy functionals from other theories.
\\ ( , 16kb)
Date: Fri, 14 Dec 2007 20:16:31 GMT (44kb)

Title: The model of interacting spatial permutations and its relation to the
   Bose gas
Authors: Daniel Ueltschi
Categories: cond-mat.stat-mech
Comments: 13 pages
   The model of spatial permutations is related to the Feynman-Kac
representation of the Bose gas. The transition to infinite cycles corresponds
to Bose-Einstein condensation. We review the general setting and some results,
and we derive a multi-body interaction between permutation jumps, that is due
to the original interactions between quantum particles.
\\ ( , 44kb)
arXiv:0712.2093 (*cross-listing*)
Date: Thu, 13 Dec 2007 04:28:36 GMT (94kb)

Title: Effective Lagrangian of unitary Fermi gas from $\varepsilon$ expansion
Authors: Andrei Kryjevski
Categories: nucl-th cond-mat.other
Comments: 17 pages, 4 figures
   Using $\varepsilon$ expansion technique proposed in \cite{Nishida:2006br} we
derive an effective Lagrangian (Ginzburg-Landau-like functional) of the
degenerate unitary Fermi gas to the next-to-leading (NLO) order in
$\varepsilon.$ It is demonstrated that for many realistic situations it is
sufficient to retain leading order (LO) terms in the derivative expansion. The
functional is used to study vortex structure in the symmetric gas, and
interface between normal and superfluid phases in the polarized gas. The
resulting surface free energy is about four times larger than the value
previously quoted in the literature.
\\ ( , 94kb)
Date: Fri, 14 Dec 2007 18:50:12 GMT (345kb)

Title: Continuous variable versus EIT-based quantum memories
Authors: Z. Kurucz and M. Fleischhauer
Categories: quant-ph
Comments: 12 pages, 4 figures
   We discuss a general model of a quantum memory for a single light mode in a
collective mode of atomic oscillators. The model includes interaction
Hamiltonians that are of second order in the canonical position and momentum
operators of the light- and atomic oscillator modes. We also consider the
possibility of measurement and feedback. We identify an interaction Hamiltonian
that leads to an ideal mapping by pure unitary evolution and compare several
schemes which realize this mapping using a common continuous-variable
description. In particular we discuss schemes based on the off-resonant Faraday
effect supplemented by measurement and feedback and proper preparation of the
atoms in a squeezed state and schemes based on off-resonant Raman coupling as
well as electromagnetically induced transparency (EIT).
\\ ( , 345kb)
Date: Sat, 15 Dec 2007 04:21:56 GMT (85kb)

Title: Evaluation of the Permutational Structure of the Canonical Ensemble
   Partition Function
Authors: Ryan Springall, Manolo Per and Ian K. Snook
Categories: cond-mat.stat-mech
Comments: 6 Figures, 8 pages
Journal-ref: Phys. Rev. E 75, 031124 (2007)
   Proposed is an alternative method for permutational sampling in quantum gases
using the path integral formulation of statistical mechanics. It is shown that
in principle we are able to use two operators which enable us to construct a
Markov chain through a graph of the irreducible representation of the symmetric
group. As an illustration of this method, a test calculation of four particles
in a harmonic trap is performed.
\\ ( , 85kb)
Date: Sat, 15 Dec 2007 05:50:15 GMT (88kb)

Title: On the Quantum Instability of Attractive Bose Systems
Authors: George E. Cragg and Arthur K. Kerman
Categories: cond-mat.other
Comments: 59 pages, 6 figures
   We explore the zero-temperature behavior of an assembly of bosons interacting
through a zero-range, attractive potential. Because the two-body interaction
admits a bound state, the many-body model is best described by a Hamiltonian
that includes the coupling between atomic and molecular components. Due to the
positive scattering length, the low-density collection is expected to remain
stable against collapse despite the attraction between particles. Through a
variational many-body analysis, we find that the usual solution is obtained
only if the chemical potential is allowed to be complex valued. Expanding in
small oscillations reveals that the imaginary part of the chemical potential
signifies a coherent decay of the quantum state into collective phonon
excitations of a collapsing lower state.
\\ ( , 88kb)
Date: Sun, 16 Dec 2007 13:56:41 GMT (810kb,D)

Title: Integer quantum Hall effect in constant non-Abelian "magnetic" fields
Authors: N. Goldman, A. Kubasiak and M. Lewenstein
Categories: cond-mat.mes-hall
Comments: 4 pages, 4 figures
   We study a fundamental problem regarding the physics of fermionic atoms in a
constant non-Abelian U(2) "magnetic" field. The energy spectrum reveals a
robust band structure and exhibits large bandgaps. We characterize the integer
quantum Hall effect and the quantized Hall conductivity in such systems by
calculating the Chern numbers associated to the non-Abelian Berry's curvature.
We eventually describe this phenomenon through a striking fractal phase
\\ ( , 810kb)
Date: Thu, 13 Dec 2007 20:24:52 GMT (1285kb,D)

Title: Bosons in one-dimensional incommensurate superlattices
Authors: Tommaso Roscilde
Categories: cond-mat.dis-nn cond-mat.str-el
Comments: 22 pages, 28 figures
   We investigate numerically the zero-temperature physics of the
one-dimensional Bose-Hubbard model in an incommensurate cosine potential,
recently realized in experiments with cold bosons in optical superlattices L.
Fallani et al., Phys. Rev. Lett. 98, 130404, (2007)]. An incommensurate cosine
potential has intermediate properties between a truly periodic and a fully
random potential, displaying a characteristic length scale (the quasi-period)
which is shown to set a finite lower bound to the excitation energy of the
system at special incommensurate fillings. This leads to the emergence of
gapped incommensurate band-insulator (IBI) phases along with gapless Bose-glass
(BG) phases for strong quasi-periodic potential, both for hardcore and softcore
bosons. Enriching the spatial features of the potential by the addition of a
second incommensurate component appears to remove the IBI regions, stabilizing
a continuous BG phase over an extended parameter range. Moreover we discuss the
validity of the local-density approximation in presence of a parabolic trap,
clarifying the notion of a local BG phase in a trapped system; we investigate
the behavior of first- and second-order coherence upon increasing the strength
of the quasi-periodic potential; and we discuss the ab-initio derivation of the
Bose-Hubbard Hamiltonian with quasi-periodic potential starting from the
microscopic Hamiltonian of bosons in an incommensurate superlattice.
\\ ( , 1285kb)
Date: Sat, 15 Dec 2007 01:01:36 GMT (760kb,D)

Title: Entangling identical bosons in optical tweezers via exchange interaction
Authors: Nathan S. Babcock, Rene Stock, Mark G. Raizen, Barry C. Sanders
Categories: quant-ph
Comments: 9 pages, 3 figures
   We first devise a scheme to perform a universal entangling gate via
controlled collisions between pairs of atomic qubits trapped with optical
tweezers. Second, we present a modification to this scheme to allow the
preparation of atomic Bell pairs via selective excitation, suitable for quantum
information processing applications that do not require universality. Both
these schemes are enabled by the inherent symmetries of identical composite
particles, as originally proposed by Hayes et al. Our scheme provides a
technique for producing weighted graph states, entangled resources for quantum
communication, and a promising approach to performing a "loophole free" Bell
test in a single laboratory.
\\ ( , 760kb)
Date: Sun, 16 Dec 2007 10:17:47 GMT (480kb)

Title: Atom--photon momentum entanglement with quantum interference
Authors: Rui Guo and Hong Guo
Categories: quant-ph
Comments: 4 pages, 4 figures
   With quantum interference of two-path spontaneous emissions, we propose a
novel scheme to coherently control the atom--photon momentum entanglement
through atomic internal coherence. A novel phenomenon called ``momentum phase
entanglement'' is reported, and we found, under certain conditions, that more
controllable entangled state can be produced with super--high degree of
\\ ( , 480kb)
Date: Sun, 16 Dec 2007 11:06:47 GMT (221kb)

Title: Event-based computer simulation model of Aspect-type experiments
   strictly satisfying Einstein's locality conditions
Authors: Hans De Raedt, Koen De Raedt, Kristel Michielsen, Koenraad Keimpema,
   and Seiji Miyashita
Categories: quant-ph
Journal-ref: J. Phys. Soc. Jpn. 76, 104005 (2007)
DOI: 10.1143/JPSJ.76.104005
   Inspired by Einstein-Podolsky-Rosen-Bohm experiments with photons, we
construct an event-based simulation model in which every essential element in
the ideal experiment has a counterpart. The model satisfies Einstein's criteria
of local causality and does not rely on concepts of quantum and probability
theory. We consider experiments in which the averages correspond to those of a
singlet and product state of a system of two $S=1/2$ particles. The data is
analyzed according to the experimental procedure, employing a time window to
identify pairs. We study how the time window and the passage time of the
photons, which depends on the relative angle between their polarization and the
polarizer's direction, influences the correlations, demonstrating that the
properties of the optical elements in the observation stations affect the
correlations although the stations are separated spatially and temporarily. We
show that the model can reproduce results which are considered to be
intrinsically quantum mechanical.
\\ ( , 221kb)
Date: Sun, 16 Dec 2007 14:21:50 GMT (361kb)

Title: Event-by-event simulation of quantum phenomena
Authors: H. De Raedt
Categories: quant-ph
Comments: V Brazilian Meeting on Simulational Physics, Ouro Preto, 2007
   In this talk, I discuss recent progress in the development of simulation
algorithms that do not rely on any concept of quantum theory but are
nevertheless capable of reproducing the averages computed from quantum theory
through an event-by-event simulation. The simulation approach is illustrated by
applications to single-photon Mach-Zehnder interferometer experiments and
Einstein-Podolsky-Rosen-Bohm experiments with photons.
\\ ( , 361kb)
Date: Mon, 17 Dec 2007 12:25:23 GMT (11kb)

Title: On Bargmann Representations of Wigner Function
Authors: Fernando Parisio
Categories: quant-ph
Comments: accepted for publication in J. Phys. A: Math. and Theor
   By using the localized character of canonical coherent states, we give a
straightforward derivation of the Bargmann integral representation of Wigner
function (W). A non-integral representation is presented in terms of a
quadratic form V*FV, where F is a self-adjoint matrix whose entries are
tabulated functions and V is a vector depending in a simple recursive way on
the derivatives of the Bargmann function. Such a representation may be of use
in numerical computations. We discuss a relation involving the geometry of
Wigner function and the spacial uncertainty of the coherent state basis we use
to represent it.
\\ ( , 11kb)
arXiv:0706.0757 (*cross-listing*)
Date: Wed, 6 Jun 2007 15:15:10 GMT (673kb)

Title: Fractional Quantum Hall Effect in Optical Lattices
Authors: Mohammad Hafezi, Anders S. Sorensen, Eugene Demler, Mikhail D. Lukin
Categories: cond-mat.mes-hall quant-ph
Comments: 18 pages, 12 figures
Journal-ref: Phys. Rev. A 76, 023613 (2007)
DOI: 10.1103/PhysRevA.76.023613
   We analyze a recently proposed method to create fractional quantum Hall (FQH)
states of atoms confined in optical lattices [A. S{\o}rensen {\it et al.},
Phys. Rev. Lett. {\bf 94} 086803 (2005)]. Extending the previous work, we
investigate conditions under which the FQH effect can be achieved for bosons on
a lattice with an effective magnetic field and finite onsite interaction.
Furthermore, we characterize the ground state in such systems by calculating
Chern numbers which can provide direct signatures of topological order and
explore regimes where the characterization in terms of wavefunction overlap
fails. We also discuss various issues which are relevant for the practical
realization of such FQH states with ultracold atoms in an optical lattice,
including the presence of the long-range dipole interaction which can improve
the energy gap and stabilize the ground state. We also investigate a new
detection technique based on Bragg spectroscopy to probe these system in an
experimental realization.
\\ ( , 673kb)
Date: Tue, 18 Dec 2007 10:16:10 GMT (7kb)

Title: On the Transition to Turbulence of Oscillatory Flow of Liquid Helium-4
Authors: W. Schoepe
Categories: cond-mat.other
   Oscillating solid bodies have frequently been used for studying the
properties of normal and superfluid helium. In particular, the transition from
laminar flow to turbulence has attracted much interest recently. The purpose of
this note is to review several central features of this transition in
oscillatory flow, which have been inaccurately formulated in some recent work.
\\ ( , 7kb)
Date: Tue, 18 Dec 2007 12:33:05 GMT (728kb)

Title: Giant vortex and Skyrmion in a rotating two-species Bose-Einstein
Authors: Shi-Jie Yang, Quan-Sheng Wu, Sheng-Nan Zhang, and Shiping Feng
Categories: cond-mat.other
Comments: 5 pages, 5 figures
   Numerical simulations are performed for a rotating two-species Bose
condensate confined by a harmonic potential. The particle numbers of each
species are unequal. When the rotational speed exceeds a critical value, the
majority species reside in the center of the potential while the minority
species is pushed out to the outskirts, forming a giant vortex hole to contain
the majority species. A novel annular Skyrmion forms at the interface of the
two species.
\\ ( , 728kb)
Date: Tue, 18 Dec 2007 13:06:44 GMT (252kb)

Title: Discrete chaotic states of a Bose-Einstein condensate
Authors: Wenhua Hai, Shiguang Rong, Qianquan Zhu
Categories: cond-mat.other
Comments: 4 pages, 5 figures
   We find the different chaotic states in a one-dimensional attractive
Bose-Einstein condensate with Gaussian-like laser barrier potential and
perturbed by a weak optical lattice. Existences of the Smale-horseshoe chaos
and the chaotic region of parameters are demonstrated. A bounded chaotic
solution which describes a set of spatially chaotic states is constructed for
the discrete laser barrier heights. The chaotic density profiles are exhibited
numerically for the lowest quantum number, by which the analytically bounded
but numerically unbounded Gaussian-like configurations are illustrated. It is
shown that the amplitude, site and width of the chaotic wave packets can be
controlled experimentally by adjusting the height, site and width of the laser
barrier potential.
\\ ( , 252kb)
Date: Tue, 18 Dec 2007 17:20:49 GMT (409kb)

Title: Collisions of bright solitary matter waves
Authors: N. G. Parker, A. M. Martin, S. L. Cornish and C. S. Adams
Categories: cond-mat.other
Comments: 9 pages, 4 colour figures
   The collisions of three-dimensional bright solitary matter waves formed from
atomic Bose-Einstein condensates are shown to exhibit rich behaviour.
Collisions range from being elastic to completely destructive due to the onset
of collapse during the interaction. Through a detailed quantitative analysis we
map out the role of relative phase, impact speed and interaction strength. In
particular, we identify the importance of the collapse time in the onset of
unstable collisions and show how the relative phase controls a population
transfer between the waves. Our analysis enables us to interpret recent
experimental observations of bright solitary matter waves.
\\ ( , 409kb)
arXiv:0712.2810 (*cross-listing*)
Date: Mon, 17 Dec 2007 20:43:09 GMT (15kb)

Title: Ground state energy of the low density Hubbard model
Authors: Robert Seiringer, Jun Yin
Categories: math-ph cond-mat.stat-mech math.MP
Comments: LaTeX2e, 18 pages
   We derive a lower bound on the ground state energy of the Hubbard model for
given value of the total spin. In combination with the upper bound derived
previously by Giuliani, our result proves that in the low density limit, the
leading order correction compared to the ground state energy of a
non-interacting lattice Fermi gas is given by $8\pi a \rho_u \rho_d$, where
$\rho_{u(d)}$ denotes the density of the spin-up (down) particles, and $a$ is
the scattering length of the contact interaction potential. This result extends
previous work on the corresponding continuum model to the lattice case.
\\ ( , 15kb)
Date: Tue, 18 Dec 2007 13:26:00 GMT (233kb)

Title: Twin stimulated amplification of light and matter waves in an
   atom-photon pair laser
Authors: Thomas Salzburger, Helmut Ritsch
Categories: quant-ph
   We consider ultracold atoms in a far detuned optical lattice orientated
across a high-Q optical resonator. Applying an external driving laser to the
atoms, which is red detuned from the cavity mode by one vibrational quantum,
induces cavity-enhanced sideband cooling. For a dense and cold enough atomic
ensemble we predict an oscillation threshold for optical Raman sideband lasing
concurrent with coherent matter-wave amplification. Above this oscillation
threshold photons and atoms in the lowest band are dominantly created pairwise
via stimulated emission with a strong suppression of competing spontaneous
processes. In close analogy to a nondegenerate parametric oscillator we find
sub-Poissonian photon statistics and almost perfect nonclassical atom-photon
number correlations. Injecting atoms in higher vibrational bands via tunneling
or incoherent scattering then leads to continuous, simultaneous generation of a
coherent atom beam and laser light with nonclassical atom-field correlations.
\\ ( , 233kb)
Date: Wed, 19 Dec 2007 13:27:57 GMT (36kb)

Title: Fermions out of Dipolar Bosons in the lowest Landau level
Authors: Brice Chung, Thierry Jolicoeur
Categories: cond-mat.mes-hall
Comments: 12 pages, 5 figures
   In the limit of very fast rotation atomic Bose-Einstein condensates may
reside entirely in the lowest two-dimensional Landau level (LLL). For small
enough filling factor of the LLL, one may have formation of fractional quantum
Hall states. We investigate the case of bosons with dipolar interactions as may
be realized with Chromium-52 atoms. We show that at filling factor equal to
unity the ground state is a Moore-Read (a.k.a Pfaffian) paired state as is the
case of bosons with purely s-wave scattering interactions. This Pfaffian state
is destabilized when the interaction in the s-wave channel is small enough and
the ground state is a stripe phase with unidimensional density modulation. For
filling factor 1/3, we show that there is formation of a Fermi sea of
``composite fermions''. These composites are made of one boson bound with three
vortices. This phase has a wide range of stability and the effective mass of
the fermions depends essentially only of the scattering amplitude in momentum
channels larger or equal to 2. The formation of such a Fermi sea opens up a new
possible route to detection of the quantum Hall correlations by direct imaging
of the momentum distribution.
\\ ( , 36kb)
Date: Thu, 20 Dec 2007 10:42:13 GMT (250kb)

Title: Fulde-Ferrell-Larkin-Ovchinnikov superfluidity in one-dimensional
   optical lattices
Authors: M. Rizzi, Marco Polini, M.A. Cazalilla, M.R. Bakhtiari, M.P. Tosi,
   Rosario Fazio
Categories: cond-mat.str-el cond-mat.supr-con
Comments: 7 pages, 5 figures, submitted
   Spin-polarized attractive Fermi gases in one-dimensional (1D) optical
lattices are expected to be remarkably good candidates for the observation of
the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. We model these systems with
an attractive Hubbard model with population imbalance. By means of the
density-matrix renormalization-group method we compute the pairing correlations
as well as the static spin and charge structure factors in the whole range from
weak to strong coupling. We demonstrate that pairing correlations exhibit
quasi-long range order and oscillations at the wave number expected from FFLO
theory. However, we also show by numerically computing the mixed spin-charge
static structure factor that charge and spin degrees of freedom appear to be
coupled already for small imbalance. We discuss the consequences of this
coupling for the observation of the FFLO phase, as well as for the
stabilization of the quasi-long range order into long-range order by coupling
many identical 1D systems, as in quasi-1D optical lattices.
\\ ( , 250kb)
Date: Thu, 20 Dec 2007 15:50:26 GMT (52kb)

Title: Quantum phases of Fermi-Fermi mixtures in optical lattices
Authors: M. Iskin and C. A. R. Sa de Melo
Categories: cond-mat.supr-con cond-mat.other
Comments: 12 pages with 6 figures. Extended version of arXiv:cond-mat/0612496
   The ground state phase diagram of Fermi-Fermi mixtures in optical lattices is
analyzed as a function of interaction strength, population imbalance, filling
fraction and tunneling parameters. It is shown that population imbalanced
Fermi-Fermi mixtures reduce to strongly interacting Bose-Fermi mixtures in the
molecular limit, in sharp contrast to homogeneous or harmonically trapped
systems where the resulting Bose-Fermi mixture is weakly interacting.
Furthermore, insulating phases are found in optical lattices of Fermi-Fermi
mixtures in addition to the standard phase-separated or coexisting
superfluid/excess fermion phases found in homogeneous systems. The insulating
states can be a molecular Bose-Mott insulator (BMI), a Fermi-Pauli insulator
(FPI), a phase-separated BMI/FPI mixture or a Bose-Fermi checkerboard (BFC).
\\ ( , 52kb)
Date: Thu, 20 Dec 2007 18:30:01 GMT (143kb)

Title: All-Optical Production of Chromium Bose-Einstein Condensates
Authors: Q. Beaufils, R. Chicireanu, T. Zanon, B. Laburthe-Tolra, E. Marechal,
   L. Vernac, J.-C. Keller, and O. Gorceix
Categories: cond-mat.other
Comments: 4 pages, 4 figures
   We report on the production of ^52Cr Bose Einstein Condensates (BEC) with an
all-optical method. We first load 5.106 metastable chromium atoms in a 1D
far-off-resonance optical trap (FORT) from a Magneto Optical Trap (MOT), by
combining the use of Radio Frequency (RF) frequency sweeps and depumping
towards the ^5S_2 state. The atoms are then pumped to the absolute ground
state, and transferred into a crossed FORT in which they are evaporated. The
fast loading of the 1D FORT (35 ms 1/e time), and the use of relatively fast
evaporative ramps allow us to obtain in 20 s about 15000 atoms in an almost
pure condensate.
\\ ( , 143kb)
Date: Thu, 20 Dec 2007 04:47:39 GMT (1212kb)

Title: Bose-Einstein Condensation from a Rotating Thermal Cloud: Vortex
   Nucleation and Lattice Formation
Authors: A. S. Bradley, C. W. Gardiner and M. J. Davis
Categories: quant-ph
Comments: 15 pages, 12 figures
   We develop a stochastic Gross-Pitaveskii theory suitable for the study of
Bose-Einstein condensation in a {\em rotating} dilute Bose gas. The theory is
used to model the dynamical and equilibrium properties of a rapidly rotating
Bose gas quenched through the critical point for condensation, as in the
experiment of Haljan et al. [Phys. Rev. Lett., 87, 21043 (2001)]. In contrast
to stirring a vortex-free condensate, where topological constraints require
that vortices enter from the edge of the condensate, we find that phase defects
in the initial non-condensed cloud are trapped en masse in the emerging
condensate. Bose-stimulated condensate growth proceeds into a disordered vortex
configuration. At sufficiently low temperature the vortices then order into a
regular Abrikosov lattice in thermal equilibrium with the rotating cloud. We
calculate the effect of thermal fluctuations on vortex ordering in the final
gas at different temperatures, and find that the BEC transition is accompanied
by lattice melting associated with diminishing long range correlations between
vortices across the system.
\\ ( , 1212kb)
Date: Thu, 20 Dec 2007 01:38:11 GMT (194kb)

Title: Site-resolved Bragg scattering
Authors: Birjoo Vaishnav and David S. Weiss
Categories: physics.atom-ph physics.optics
   We numerically calculate the reliability with which one can optically
determine the presence or absence of an individual scatterer in a randomly
occupied 3D array of well-localized, coherently radiating scatterers. The
reliability depends in a complicated way on the ratio of lattice spacing to
wavelength and the numerical aperture of the imaging system. The behavior can
be qualitatively understood by considering the dependence of Bragg scattering
modes on lattice spacing. These results are of interest for atomic
implementations of quantum information processing.
\\ ( , 194kb)

The replacements:

replaced with revised version Fri, 14 Dec 2007 08:05:07 GMT (27kb)

Title: Feshbach resonances in mixtures of ultracold $^6$Li and $^{87}$Rb gases
Authors: B. Deh, C. Marzok, C. Zimmermann and Ph. W. Courteille
Categories: cond-mat.other cond-mat.soft
Comments: 4 pages, 3 figures
\\ ( , 27kb)
replaced with revised version Mon, 17 Dec 2007 09:32:03 GMT (11kb)

Title: Self-consistent equations of unitary fermion thermodynamics with elusive
   non-Gaussian correlations
Authors: Ji-sheng Chen, Jia-rong Li, Yan-ping Wang, Xiang-jun Xia
Categories: cond-mat.stat-mech hep-ph nucl-th quant-ph
Comments: Improved version with references updated; typos corrected
\\ ( , 11kb)
replaced with revised version Mon, 17 Dec 2007 04:30:10 GMT (71kb)

Title: Nonlinear control of chaotic walking of atoms in an optical lattice
Authors: Argonov V. Yu, S. V. Prants
Categories: quant-ph
Comments: 6 pages, 4 figures
Journal-ref: Argonov V. Yu, Prants S. V. Nonlinear control of chaotic walking
   of atoms in an optical lattice. Europhysics Letters. 2008. Vol. 81. Art. no.
\\ ( , 71kb)
replaced with revised version Tue, 18 Dec 2007 18:38:11 GMT (215kb)

Title: Mott insulator states of ultracold atoms in optical resonators
Authors: Jonas Larson, Bogdan Damski, Giovanna Morigi, Maciej Lewenstein
Categories: cond-mat.other quant-ph
Comments: 4 pages, 3 figures. Substantially revised version. To appear in Phys.
   Rev. Lett
Report-no: LAUR-06-5423
\\ ( , 215kb)
replaced with revised version Mon, 17 Dec 2007 23:12:07 GMT (116kb)

Title: Non-equilibrium spin dynamics in a trapped Fermi gas with effective
   spin-orbit interaction
Authors: Tudor D. Stanescu, Chuanwei Zhang, and Victor Galitski
Categories: cond-mat.other
Comments: 5 pages, 4 figures; published version
Journal-ref: Phys. Rev. Lett. 99, 110403 (2007)
DOI: 10.1103/PhysRevLett.99.110403
\\ ( , 116kb)
replaced with revised version Tue, 18 Dec 2007 17:32:15 GMT (148kb)

Title: Dynamics of a symmetry-restoration quantum phase transition in a
   ferromagnetic Bose-Einstein condensate
Authors: Bogdan Damski and Wojciech H. Zurek
Categories: cond-mat.other
Comments: 15 pages, 11 figures, rewritten title, expanded introduction, more
   references, single-column version, slight changes throughout the paper
Report-no: LAUR-07-7540
\\ ( , 148kb)
replaced with revised version Wed, 19 Dec 2007 01:24:25 GMT (964kb)

Title: Radially Symmetric Nonlinear States of Harmonically Trapped
   Bose-Einstein Condensates
Authors: G. Herring, L. D. Carr, R. Carretero-Gonzalez, P. G. Kevrekidis, and
   D. J. Frantzeskakis
Categories: cond-mat.other
Comments: 10 pages, 16 figures (some with low resolution)
\\ ( , 964kb)
replaced with revised version Thu, 20 Dec 2007 18:10:56 GMT (51kb)

Title: Number fluctuations in cold quantum gases
Authors: G.E. Astrakharchik, R. Combescot, L.P. Pitaevskii
Categories: cond-mat.stat-mech
Comments: Minor changes due to referee comments
Journal-ref: Phys. Rev. A 76, 063616 (2007)
\\ ( , 51kb)
replaced with revised version Thu, 20 Dec 2007 11:39:18 GMT (299kb)

Title: Quantum stability of self-organized atomic insulator-like states in
   optical resonators
Authors: Jonas Larson, Sonia Fernandez-Vidal, Giovanna Morigi, Maciej
Categories: cond-mat.other quant-ph
Comments: 13 pages, 6 figures. Replaced with revised version. Accepted for
   publication in New J. Phys., special issue "Quantum correlations in tailord
\\ ( , 299kb)
replaced with revised version Thu, 20 Dec 2007 14:53:59 GMT (34kb)

Title: Competing Orders in One-Dimensional Half-Integer Fermionic Cold Atoms: A
   Conformal Field Theory Approach
Authors: P. Lecheminant, P. Azaria, and E. Boulat
Categories: cond-mat.str-el hep-th
Comments: 35 pages, 3 figures
\\ ( , 34kb)

Till next time,

Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email:
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Matt's arXiv selection: weekly summary of cold-atom papers from
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Received on Thu Jan 03 2008 - 11:09:23 EST

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