Matt's arXiv selection: week ending 30th March 2007.

From: Matthew Davis <>
Date: Thu, 5 Apr 2007 15:49:30 +1000 (EST)

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

Hi everyone,

A total of 18 new abstracts and 8 replacements this week: relatively quiet. One
that stood out to me was the report of the achievement of BEC in potassium-39 in

Paper: cond-mat/0703603
Date: Fri, 23 Mar 2007 06:18:35 GMT (184kb)

Title: Quantum Turbulence in a Trapped Bose-Einstein Condensate
Authors: Michikazu Kobayashi and Makoto Tsubota
Categories: cond-mat.dis-nn cond-mat.stat-mech
Comments: 4 pages, 4 figures, manuscript submitted to APS
Subj-class: Disordered Systems and Neural Networks; Statistical Mechanics
   We first propose quantum turbulence in trapped Bose-Einstein condensates by
numerically studying the Gross-Pitaevskii equation. Combining rotations around
two axes, we successfully induce quantum turbulent state in which quantized
vortices are not crystallized but tangled. The obtained spectrum of the
incompressible kinetic energy is consistent with the Kolmogorov law, the most
important statistical law in turbulence.
\\ ( , 184kb)
Paper: cond-mat/0703610
Date: Fri, 23 Mar 2007 10:53:32 GMT (60kb)

Title: Dynamics of one-dimensional Bose liquids: Andreev-like reflection at
   Y-junctions and absence of the Aharonov-Bohm effect
Authors: Akiyuki Tokuno, Masaki Oshikawa, Eugene Demler
Categories: cond-mat.other cond-mat.mes-hall
Comments: 4pages, 3figures
Subj-class: Other; Mesoscopic Systems and Quantum Hall Effect
   We study one dimensional Bose liquids of interacting ultracold atoms in the
Y-shaped potential when each branch is filled with atoms. We find that the
excitation packet incident on a single Y-junction should experience a negative
density reflection analogous to the Andreev reflection at normal-superconductor
interfaces, although the present system does not contain fermions. In a ring
interferometer type configuration, we find that the transport is completely
insensitive to the (effective) flux contained in the ring, in contrast to the
Aharonov-Bohm effect of a single particle in the same geometry.
\\ ( , 60kb)
Paper: cond-mat/0703612
Date: Fri, 23 Mar 2007 11:34:30 GMT (24kb)

Title: Manifestation of a gap due to the exchange energy in a spinor condensate
Authors: Patrick Navez
Categories: cond-mat.stat-mech
Comments: 4 pages, 2 figures. submitted to Phys. Rev. Lett
Subj-class: Statistical Mechanics
   We investigate the dynamic response of population transfer between two
components of a finite temperature spinor Bose condensed gas to a
time-dependent coupling potential. Comparison between results obtained in the
Bogoliubov-Popov approximation (BPA) and in the generalized random phase
approximation (GRPA) shows noticeable discrepancies. In particular, the
inter-component current response function calculated in the GRPA displays a
gapped spectrum due to the exchange interaction energy whereas the
corresponding density response function is gapless. We argue that the GRPA is
superior since, contrary to the BPA, it preserves the SU(2) symmetry and the
f-sum rule associated to the spinor gas. In order to validate the
approximation, we propose an experimental setup that allows the observation of
the predicted gap.
\\ ( , 24kb)
Paper: cond-mat/0703620
Date: Fri, 23 Mar 2007 14:35:50 GMT (194kb)

Title: Quantum melting of a crystal of dipolar bosons
Authors: Christophe Mora, Olivier Parcollet, Xavier Waintal
Categories: cond-mat.stat-mech
Comments: 10 pages, 8 figures
Subj-class: Statistical Mechanics
   We investigate the behaviour of dipolar bosons in two dimensions. We describe
the large density crystalline limit analytically while we use quantum
Monte-Carlo to study the melting toward the Bose-Einstein condensate. We find
strong evidence for a first order transition. We characterize the window of
experimentally accessible parameters in the context of ultracold bosons and
show that observing the quantum melting should be within grasp once one is able
to form cold heteronuclear molecules. Close to the melting, we can not conclude
on the existence of a supersolid phase due to an insufficient overlap of our
variational Bijl-Jastrow Ansatz with the actual ground state.
\\ ( , 194kb)
Paper: quant-ph/0703221
Date: Fri, 23 Mar 2007 14:04:53 GMT (112kb)

Title: Microscopic physics of quantum self-organisation of optical lattices in
Authors: Andr\'as Vukics, Christoph Maschler, and Helmut Ritsch
Categories: quant-ph
Comments: 14 pages 6 figures
   We study quantum particles at zero temperature in an optical lattice coupled
to a resonant cavity mode. The cavity field substantially modifies the particle
dynamics in the lattice, and for strong particle-field coupling leads to a
quantum phase with only every second site occupied. We study the growth of this
new order out of a homogeneous initial distribution for few particles as the
microscopic physics underlying a quantum phase transition. Simulations reveal
that the growth dynamics crucially depends on the initial quantum many-body
state of the particles and can be monitored via the cavity fluorescence.
Studying the relaxation time of the ordering reveals inhibited tunnelling,
which indicates that the effective mass of the particles is increased by the
interaction with the cavity field. However, the relaxation becomes very quick
for large coupling.
\\ ( , 112kb)
Paper: cond-mat/0703674
Date: Mon, 26 Mar 2007 12:54:47 GMT (686kb)

Title: Interference of Degenerate Polariton Condensates in Microcavities
Authors: T C H Liew, A V Kavokin, I A Shelykh
Categories: cond-mat.mes-hall
Comments: 4 pages, 4 figures
Subj-class: Mesoscopic Systems and Quantum Hall Effect
   We demonstrate theoretically that the interaction of two degenerate
condensates of exciton-polaritons in microcavities leads to polarization
dependent parametric oscillations. The resonant polariton-polariton scattering
is governed by the polarization of the condensates and can be fully suppressed
for certain polarizations. A polarization controlled solid state optical gate
is proposed.
\\ ( , 686kb)
Paper (*cross-listing*): gr-qc/0703117
Date: Fri, 23 Mar 2007 08:33:42 GMT (67kb)

Title: Trans-Planckian physics and signature change events in Bose gas
Authors: Silke Weinfurtner (Victoria University of Wellington), Angela White
   (The Australian National University), and Matt Visser (Victoria University of
Categories: gr-qc cond-mat.soft hep-th
Comments: 18 pages, revtex4
Subj-class: General Relativity and Quantum Cosmology; Soft Condensed Matter
   We present an example of emergent spacetime as the hydrodynamic limit of a
more fundamental microscopic theory. The low-energy, long-wavelength limit in
our model is dominated by collective variables that generate an effective
Lorentzian metric. This system naturally exhibits a microscopic mechanism
allowing us to perform controlled signature change between Lorentzian and
Riemannian geometries. We calculate the number of particles produced from a
finite-duration Euclidean-signature event, where we take the position that to a
good approximation the dynamics is dominated by the evolution of the linearized
perturbations, as suggested by Calzetta and Hu [Phys. Rev. A 68 (2003) 043625].
We adapt the ideas presented by Dray et al. [Gen. Rel. Grav. 23 (1991) 967],
such that the field and its canonical momentum are continuous at the
signature-change event.
   We investigate the interplay between the underlying microscopic structure and
the emergent gravitational field, focussing on its impact on particle
production in the ultraviolet regime. In general, this can be thought of as the
combination of trans-Planckian physics and signature-change physics. Further we
investigate the possibility of using the proposed signature change event as an
amplifier for analogue "cosmological particle production" in condensed matter
\\ ( , 67kb)
Paper: cond-mat/0703688
Date: Mon, 26 Mar 2007 23:01:10 GMT (292kb,D)

Title: Three-body interactions with cold polar molecules
Authors: H.P. B\"uchler, A. Micheli, and P. Zoller
Categories: cond-mat.stat-mech
Comments: 8 pages, 4 figures
Report-no: NSF-KITP-07-43
Subj-class: Statistical Mechanics
   We show that polar molecules driven by microwave fields give naturally rise
to strong three-body interactions, while the two-particle interaction can be
independently controlled and even switched off. The derivation of these
effective interaction potentials is based on a microscopic understanding of the
underlying molecular physics, and follows from a well controlled and systematic
expansion into many-body interaction terms. For molecules trapped in an optical
lattice, we show that these interaction potentials give rise to Hubbard models
with strong nearest-neighbor two-body and three-body interaction. As an
illustration, we study the one-dimensional Bose-Hubbard model with dominant
three-body interaction and derive its phase diagram.
\\ ( , 292kb)
Paper: cond-mat/0703714
Date: Tue, 27 Mar 2007 13:22:51 GMT (236kb)

Title: 39-K Bose-Einstein condensate with tunable interactions
Authors: G. Roati, M. Zaccanti, C. D'Errico, J. Catani, M. Modugno, A. Simoni,
   M. Inguscio, and G. Modugno
Categories: cond-mat.other
Comments: 5 pages
Subj-class: Other
   We produce a Bose-Einstein condensate of 39-K atoms. Condensation of this
species with naturally small and negative scattering length is achieved by a
combination of sympathetic cooling with 87-Rb and direct evaporation,
exploiting the magnetic tuning of both inter- and intra-species interactions at
Feshbach resonances. We explore tunability of the self-interactions by studying
the expansion and the stability of the condensate. We find that a 39-K
condensate is interesting for future experiments requiring a weakly interacting
Bose gas.
\\ ( , 236kb)
Paper: cond-mat/0612361
replaced with revised version Tue, 27 Mar 2007 10:30:57 GMT (70kb)

Title: Coupling of hydrodynamics and quasiparticle motion in collective modes
   of superfluid trapped Fermi gases
Authors: M. Urban (IPNO)
Categories: cond-mat.other nucl-th
Comments: 14 pages; v2: major changes (effect of Hartree field included)
Proxy: ccsd in2p3-00120317
Subj-class: Other
\\ ( , 70kb)
Paper: quant-ph/0703247
Date: Mon, 26 Mar 2007 20:41:13 GMT (707kb)

Title: Coherent atom-trimer conversion in a repulsive Bose-Einstein condensate
Authors: H. Jing, J. Cheng, and P. Meystre
Categories: quant-ph
Comments: 3 figures
   We show that the use of a generalized atom-molecule dark state permits the
enhanced coherent creation of triatomic molecules in a repulsive atomic
Bose-Einstein condensate, with further enhancement being possible in the case
of heteronuclear trimers via the constructive interference between two chemical
reaction channels.
\\ ( , 707kb)
Paper: cond-mat/0703731
Date: Tue, 27 Mar 2007 22:26:46 GMT (327kb)

Title: Degenerate Fermi gas in a combined harmonic-lattice potential
Authors: P. B. Blakie, A. Bezett, P. F. Buonsante
Categories: cond-mat.stat-mech cond-mat.soft
Comments: 11 pages, 9 figures
Subj-class: Statistical Mechanics; Soft Condensed Matter
   In this paper we derive an analytic approximation to the density of states
for atoms in a combined optical lattice and harmonic trap potential as used in
current experiments with quantum degenerate gases. We compare this analytic
density of states to numerical solutions and demonstrate its validity regime.
Our work explicitly considers the role of higher bands and when they are
important in quantitative analysis of this system. Applying our density of
states to a degenerate Fermi gas we consider how adiabatic loading from a
harmonic trap into the combined harmonic-lattice potential affects the
degeneracy temperature. Our results suggest that occupation of excited bands
during loading should lead to more favourable conditions for realizing
degenerate Fermi gases in optical lattices.
\\ ( , 327kb)
Paper: cond-mat/0703737
Date: Wed, 28 Mar 2007 04:29:40 GMT (31kb)

Title: Explanation of the Stern-Gerlach splitting of spinor condensates based
   on symmetry
Authors: Zhibing Li and Chengguang Bao
Categories: cond-mat.other cond-mat.stat-mech
Comments: 3 pages, 2 figures
Subj-class: Other; Statistical Mechanics
   The Stern-Gerlach splitting of spinor condensates is explained based on the
total spin-states with specified SU(2) and permutation symmetries.
\\ ( , 31kb)
Paper: cond-mat/0703739
Date: Wed, 28 Mar 2007 04:45:07 GMT (39kb)

Title: Characteristic frequency of the magnetic radiation of spinor condensates
Authors: Zhibing Li and Chengguang Bao
Categories: cond-mat.other cond-mat.stat-mech
Comments: 7 pages, 5 figures
Subj-class: Other; Statistical Mechanics
   The magnetic radiation of the fully-condensed states of $^{23}$Na condensates
have been studied. A narrow characteristic spectral line with a wave length
proportional to N^(-2/5) (N is the number of particles) and with a probability
of transition proportional to N^(17/5) emitted (absorbed) by the condensate was
found. It implies that short wave radiation with a huge probability of
transition can be obtained if numerous atoms are trapped. A new technique
developed by the authors, namely, the analytical forms of the fractional
parentage coefficients, was used to calculate analytically the matrix elements
between the total spin-states.
\\ ( , 39kb)
Paper: cond-mat/0703755
Date: Wed, 28 Mar 2007 11:48:46 GMT (6kb)

Title: Condensate superfluidity and infrared structure: the Josephson relation
Authors: Markus Holzmann and Gordon Baym
Categories: cond-mat.stat-mech
Comments: 4 pages, no figures
Subj-class: Statistical Mechanics
   We derive the Josephson relation in a superfluid between the condensate
density, the superfluid mass density, and the infrared structure of the single
particle Green's function by means of diagrammatic perturbation theory. The
derivation is valid for finite systems and two dimensions.
\\ ( , 6kb)
Paper: cond-mat/0703766
Date: Wed, 28 Mar 2007 20:01:11 GMT (735kb)

Title: Fundamental noise in matter interferometers
Authors: Adilet Imambekov, Vladimir Gritsev and Eugene Demler
Categories: cond-mat.other cond-mat.stat-mech
Comments: 47 pages, 17 figures, to be published in the Proceedings of the 2006
   Enrico Fermi Summer School on "Ultracold Fermi gases", organized by M.
   Inguscio, W. Ketterle and C.Salomon (Varenna, Italy, June 2006)
Subj-class: Other; Statistical Mechanics
   These lecture notes discuss two effects which contribute to the reduction of
the interference fringe contrast in matter interferometers. The first effect is
the shot noise arising from a finite number of atoms used in experiments.
Focusing on a single shot measurement we provide explicit calculations of the
full distribution functions of the fringe contrast for the interference of
either the coherent or the number states of atoms. Another mechanism of the
suppression of the amplitude of interference fringes discussed in these lecture
notes is the quantum and thermal fluctuations of the order parameter in low
dimensional condensates. We summarize recent theoretical and experimental
studies demonstrating that suppression of the interference fringe contrast and
its shot to shot variations can be used to study correlation functions within
individual condensates. We also discuss full distribution functions of the
fringe amplitudes for one and two dimensional condensates and review their
connection to high order correlation functions. We point out intriguing
mathematical connections between the distribution functions of interference
fringe amplitudes and several other problems in field theory, systems of
correlated electrons, and statistical physics.
\\ ( , 735kb)
Paper: cond-mat/0703768
Date: Wed, 28 Mar 2007 20:13:05 GMT (45kb)

Title: The strong coupling Kondo lattice model as a Fermi gas
Authors: S. Ostlund
Categories: cond-mat.str-el
Comments: 10pages, 2 figures
Subj-class: Strongly Correlated Electrons
   The strong coupling half-filled Kondo lattice model is an important example
of a strongly interacting dense Fermi system for which conventional Fermi gas
analysis has thus far failed. We remedy this by deriving an exact
transformation that maps the model to a dilute gas of weakly interacting
electron and hole quasiparticles that can then be analyzed by conventional
dilute Fermi gas methods. The quasiparticle vacuum is a singlet Mott insulator
for which the quasiparticle dynamics are simple. Since the transformation is
exact, the electron spectral weight sum rules are obeyed exactly. Subtleties in
understanding the behavior of electrons in the singlet Mott insulator can be
reduced to a fairly complicated but precise relation between quasiparticles and
bare electrons. The theory of free quasiparticles can be interpreted as an
exactly solvable model for a singlet Mott insulator, providing an exact model
in which to explore the strong coupling regime of a singlet Kondo insulator.
\\ ( , 45kb)
Paper: cond-mat/0703779
Date: Thu, 29 Mar 2007 10:48:06 GMT (21kb)

Title: Ansatz from Non-Linear Optics Applied to Trapped Bose-Einstein
Authors: Murat Keceli, F.O. Ilday, M.O. Oktel
Categories: cond-mat.other
Comments: 4 pages, 3 figures, published version
Subj-class: Other
Journal-ref: Phys. Rev. A 75, 035601 (2007)
DOI: 10.1103/PhysRevA.75.035601
   A simple analytical ansatz, which has been used to describe the intensity
profile of the similariton laser (a laser with self-similar propagation of
ultrashort pulses), is used as a variational wave function to solve the
Gross-Pitaevskii equation for a wide range of interaction parameters. The
variational form interpolates between the noninteracting density profile and
the strongly interacting Thomas-Fermi profile smoothly. The simple form of the
ansatz is modified for both cylindrically symmetric and completely anisotropic
harmonic traps. The resulting ground-state density profile and energy are in
very good agreement with both the analytical solutions in the limiting cases of
interaction and the numerical solutions in the intermediate regime.
\\ ( , 21kb)
Paper: cond-mat/0703780
Date: Thu, 29 Mar 2007 10:57:00 GMT (34kb)

Title: Photonic Band Gap in the Triangular Lattice of BEC vortices
Authors: M.E. Tasgin, O.E. Mustecaplioglu, M.O. Oktel
Categories: cond-mat.other
Comments: 8 pages, 6 figures
Subj-class: Other
   We investigate the photonic bands of an atomic Bose-Einstein condensate with
a triangular vortex lattice. Index contrast between the vortex cores and the
bulk of the condensate is achieved through the enhancement of the index via
atomic coherence. Frequency dependent dielectric function is used in the
calculations of the bands, resulting in photonic band gap widths of a few MHz.
\\ ( , 34kb)
Paper (*cross-listing*): nucl-th/0610105
replaced with revised version Thu, 29 Mar 2007 08:13:29 GMT (33kb)

Title: Universal Properties of the Four-Body System with Large Scattering
Authors: H.-W. Hammer (Bonn U.), L. Platter (Ohio U.)
Categories: nucl-th cond-mat.other
Comments: 14 pages, 4 ps figures, minor changes, version to appear in EPJA
Report-no: HISKP-TH-06/31
Subj-class: Nuclear Theory; Other
\\ ( , 33kb)

The replacements:

Paper: cond-mat/0612456
replaced with revised version Fri, 23 Mar 2007 13:14:22 GMT (76kb)

Title: Confinement vs Deconfinement of Cooper Pairs in One-Dimensional Spin-3/2
   Fermionic Cold Atoms
Authors: S. Capponi, G. Roux, P. Azaria, E. Boulat, P. Lecheminant
Categories: cond-mat.str-el cond-mat.supr-con
Comments: Published version with minor changes; 4 pages, 7 figures
Subj-class: Strongly Correlated Electrons; Superconductivity
Journal-ref: Phys. Rev. B 75, 100503(R) (2007)
DOI: 10.1103/PhysRevB.75.100503
\\ ( , 76kb)
Paper: cond-mat/0612460
replaced with revised version Mon, 26 Mar 2007 12:29:12 GMT (28kb)

Title: Shear viscosity and damping for a Fermi gas in the unitarity limit
Authors: G. M. Bruun, H. Smith
Categories: cond-mat.stat-mech hep-ph
Comments: 7 pages, 3 figures. Discussion significantly extended. Appendix
   added. To appear in PRA
Subj-class: Statistical Mechanics
\\ ( , 28kb)
Paper: cond-mat/0703585
replaced with revised version Sat, 24 Mar 2007 16:02:12 GMT (21kb)

Title: Temperature Dependence of Critical Number of Particles for Attracting
   Atomic Bose Gas
Authors: Shyamal Biswas
Categories: cond-mat.stat-mech
Comments: 7 pages, 3 figures
Subj-class: Statistical Mechanics
\\ ( , 21kb)
Paper: quant-ph/0703221
replaced with revised version Mon, 26 Mar 2007 10:10:33 GMT (112kb)

Title: Microscopic physics of quantum self-organisation of optical lattices in
Authors: Andr\'as Vukics, Christoph Maschler, and Helmut Ritsch
Categories: quant-ph
Comments: 14 pages 6 figures
\\ ( , 112kb)
Paper: quant-ph/0612044
replaced with revised version Tue, 27 Mar 2007 16:35:16 GMT (806kb)

Title: Bell-type inequalities for cold heteronuclear molecules
Authors: Perola Milman (PPM, CERMICS), Arne Keller (PPM), Eric Charron (PPM),
   Osman Atabek (PPM)
Categories: quant-ph
Comments: 4 pages
Proxy: ccsd hal-00118788
\\ ( , 806kb)
Paper: cond-mat/0603190
replaced with revised version Wed, 28 Mar 2007 13:40:46 GMT (18kb)

Title: Realization, Characterization, and Detection of Novel Superfluid Phases
   with Pairing between Unbalanced Fermion Species
Authors: Kun Yang
Categories: cond-mat.supr-con hep-ph nucl-th
Comments: Final version as appeared in print. 20 pages
Subj-class: Superconductivity
Journal-ref: Invited contribution to: Pairing in Fermionic Systems: Basic
   Concepts and Modern Applications (Mark Alford, John Clark and Armen
   Sedrakian, eds), World Scientific (2006), page 253-268
\\ ( , 18kb)
Paper (*cross-listing*): gr-qc/0610047
replaced with revised version Tue, 27 Mar 2007 01:05:59 GMT (58kb)

Title: Testing General Relativity with Atom Interferometry
Authors: Savas Dimopoulos, Peter W. Graham, Jason M. Hogan, Mark A. Kasevich
Categories: gr-qc astro-ph hep-ph hep-th physics.atom-ph
Comments: 4 pages, 1 figure; v2: Minor changes made for publication
Subj-class: General Relativity and Quantum Cosmology; Atomic Physics
Journal-ref: Phys.Rev.Lett. 98:111102,2007
\\ ( , 58kb)
Paper: cond-mat/0611769
replaced with revised version Thu, 29 Mar 2007 08:55:22 GMT (94kb)

Title: Effective Range Corrections to Three-Body Recombination for Atoms with
   Large Scattering Length
Authors: H.-W. Hammer, Timo A. Lahde, L. Platter
Categories: cond-mat.other nucl-th
Comments: 6 pages, 2 figures, improved discussion, final version
Report-no: HISKP-TH-06/38, NT_at_UW-06-29
Subj-class: Other
Journal-ref: Phys.Rev. A75 (2007) 032715
\\ ( , 94kb)
Paper: cond-mat/0702318
replaced with revised version Thu, 29 Mar 2007 16:36:17 GMT (21kb)

Title: Breathing modes of a fast rotating Fermi gas
Authors: Mauro Antezza, Marco Cozzini, Sandro Stringari
Categories: cond-mat.stat-mech quant-ph
Comments: 5 pages, 2 figures
Subj-class: Statistical Mechanics
\\ ( , 21kb)

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
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 Thu Apr 05 2007 - 15:49:30 EST

This archive was generated by hypermail 2.2.0 : Thu May 08 2008 - 11:51:41 EST