From: Matthew Davis <mdavis_at_physics.uq.edu.au>

Date: Wed, 6 Jun 2007 01:57:30 +1000 (EST)

Date: Wed, 6 Jun 2007 01:57:30 +1000 (EST)

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

Hi everyone,

The date in the title of my last email was incorrect - it should have read 18th

May 2007. So this email is the week ending 25 May, and has 29 new abstracts and

16 replacements.

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arXiv:0705.2658

Date: Fri, 18 May 2007 08:51:22 GMT (20kb)

Title: The Josephson effect in the BCS-BEC crossover

Authors: A. Spuntarelli, P. Pieri, G.C. Strinati

Categories: cond-mat.other cond-mat.supr-con

Comments: 4 pages, 3 figures

\\

We study the stationary Josephson effect for neutral fermions with a mutual

attractive interaction, that ranges from weak to strong coupling across the

BCS-BEC crossover, by solving numerically the Bogoliubov-de Gennes equations

for several types of barriers with an imposed current at zero temperature.

Implementing self-consistency in the calculation proves essential, especially

on the BEC side of the crossover where we recover a description of composite

bosons in terms of the Gross-Pitaevskii equation. We show that the maximum of

the Josephson current as a function of coupling occurs for all barriers at

about unitarity. In addition, in the limit of vanishing small barrier height,

this maximum approaches the value obtained by the Landau criterion which,

depending on the coupling, is determined by either pair-breaking or sound-mode

excitations. An experiment is suggested to identify the evolution of this

maximum value through the crossover.

\\ ( http://arxiv.org/abs/0705.2658 , 20kb)

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arXiv:0705.2684

Date: Fri, 18 May 2007 12:09:20 GMT (44kb)

Title: Superfluid to Mott-insulator transition in Bose-Hubbard models

Authors: Manuela Capello, Federico Becca, Michele Fabrizio, Sandro Sorella

Categories: cond-mat.str-el

Comments: 4 pages, 4 figures, based on cond-mat/0611306

\\

We study the superfluid-insulator transition in Bose-Hubbard models in one-,

two-, and three-dimensional cubic lattices by means of a recently proposed

variational wave function. In one dimension, the variational results agree with

the expected Berezinskii-Kosterlitz-Thouless scenario of the interaction-driven

Mott transition. In two and three dimensions, we find evidences that, across

the transition,most of the spectral weight is concentrated at high energies,

suggestive of pre-formed Mott-Hubbard side-bands. This result is compatible

with the experimental data by Stoferle et al.

[Phys. Rev. Lett. 92, 130403 (2004)].

\\ ( http://arxiv.org/abs/0705.2684 , 44kb)

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arXiv:0705.2732

Date: Fri, 18 May 2007 17:38:40 GMT (225kb)

Title: Quantum phases of bosons in double-well optical lattices

Authors: Ippei Danshita, James E. Williams, Carlos A. R. Sa de Melo, and

Charles W. Clark

Categories: cond-mat.other

Comments: 5 pages, 5 figures

\\

We study the superfluid to Mott insulator transition of bosons in a

two-legged ladder optical lattice, of a type accessible in current experiments

on double-well optical lattices. The zero-temperature phase diagram is mapped

out, with a focus on its dependence upon interchain hopping and the tilt

between double wells. We find that the unit-filling Mott phase exhibits a

non-monotonic behavior as a function of the tilt parameter, producing a

reentrant phase transition between Mott insulator and superfluid phases.

\\ ( http://arxiv.org/abs/0705.2732 , 225kb)

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arXiv:0705.2750

Date: Fri, 18 May 2007 18:09:06 GMT (21kb)

Title: Ultracold Thermalization of $^7$Li and $^{87}$Rb

Authors: C. Marzok, B. Deh, Ph.W. Courteille, and C. Zimmermann

Categories: cond-mat.other

Comments: 7 pages, 4 figures, 1 table

\\

We report on measurements of cross-species thermalization inside a

magnetically trapped spin-polarized mixture of $^{87}$Rb and $^7$Li atoms with

both atoms in their respective low field seeking magnetic substates

$|F=2,m_F=2\right>$. Measurement of the thermalization velocity in the

ultracold regime below $10 \mu$K allows for the derivation of the absolute

value of the pure triplet s-wave scattering length governing the interaction.

We find $|a_{7,87}|=(59\pm19) a_{\rm B}$. We propose to study both species in

the condensed regime to derive the sign of $a_{7,87}$. In this context, we

present numerical solutions to the coupled Gross-Pitaevskii equation based on

the hypothesis of a positive sign. According to the simulations, phase

separation of the Li and Rb $|2,2\right>$ clouds occurs along with a mean-field

stabilization allowing for larger atom numbers of condensed $^7$Li atoms before

collapse sets in. Observation of this mean-field stabilization would directly

fix the sign of $a_{7,87}$. We discuss our results in the light of this

proposal.

\\ ( http://arxiv.org/abs/0705.2750 , 21kb)

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arXiv:0705.2652

Date: Fri, 18 May 2007 08:30:13 GMT (188kb)

Title: Weak-Light Ultraslow Vector Optical Solitons via Electromagnetically

Induced Transparency

Authors: Chao Hang and Guoxiang Huang

Categories: physics.optics

Comments: 4 pages, 4 figures

\\

We propose a scheme to generate temporal vector optical solitons in a

lifetime broadened five-state atomic medium via electromagnetically induced

transparency. We show that this scheme, which is fundamentally different from

the passive one by using optical fibers, is capable of achieving

distortion-free vector optical solitons with ultraslow propagating velocity

under very weak drive conditions. We demonstrate both analytically and

numerically that it is easy to realize Manakov temporal vector solitons by

actively manipulating the dispersion and self- and cross-phase modulation

effects of the system.

\\ ( http://arxiv.org/abs/0705.2652 , 188kb)

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arXiv:0705.2782

Date: Fri, 18 May 2007 21:28:49 GMT (484kb)

Title: Observation of a quenched moment of inertia in a rotating strongly

interacting Fermi gas

Authors: Bason Clancy, Le Luo, and John E. Thomas

Categories: cond-mat.other

Comments: 4 pages 5 figures

\\

We make a model-independent measurement of the moment of inertia of a

rotating, expanding strongly-interacting Fermi gas. Quenching of the moment of

inertia is observed for energies both below and above the superfluid

transition. This shows that a strongly interacting Fermi gas with angular

momentum can support irrotational flow in both the superfluid and collisional

normal fluid regimes.

\\ ( http://arxiv.org/abs/0705.2782 , 484kb)

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arXiv:cond-mat/0512317

replaced with revised version Sat, 19 May 2007 16:41:41 GMT (33kb)

Title: The axial breathing mode in rapidly rotating Bose-Einstein condensates

and uncertainty of the rotation velocity

Authors: Gentaro Watanabe

Categories: cond-mat.mes-hall cond-mat.soft nucl-th

Comments: 5 pages, 2 figures; completely revised with new findings; title

changed. This paper is related to cond-mat/0506331

Report-no: NORDITA-2005-80

\\ ( http://arxiv.org/abs/cond-mat/0512317 , 33kb)

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arXiv:0705.2922

Date: Mon, 21 May 2007 06:40:00 GMT (650kb)

Title: I.C.E.: An Ultra-Cold Atom Source for Long-Baseline Interferometric

Inertial Sensors in Reduced Gravity

Authors: Ga\"el Varoquaux (LCFIO), Nassim Zahzam (ONERA), Oualid Chaibi

(SYRTE), Jean-Fran\c{c}ois Cl\'ement (LCFIO), Olivier Carraz (ONERA),

Jean-Philippe Brantut (LCFIO), Robert A. Nyman (LCFIO), Franck Pereira Dos

Santos (SYRTE), Linda Mondin (CNES DCT/SI/OP), Michel Rouz\'e (CNES

DCT/SI/OP), Yannick Bidel (ONERA), Alexandre Bresson (ONERA), Arnaud

Landragin (SYRTE), Philippe Bouyer (LCFIO)

Categories: physics.atom-ph

Proxy: ccsd hal-00147641

Journal-ref: Rencontres de Moriond Gravitational Waves and Experimental

Gravity, Italie (11/03/2007)

\\

The accuracy and precision of current atom-interferometric inertialsensors

rival state-of-the-art conventional devices using artifact-based test masses .

Atomic sensors are well suited for fundamental measurements of gravito-inertial

fields. The sensitivity required to test gravitational theories can be achieved

by extending the baseline of the interferometer. The I.C.E.

(Interf\'erom\'etrie Coh\'erente pour l'Espace) interferometer aims to achieve

long interrogation times in compact apparatus via reduced gravity. We have

tested a cold-atom source during airplane parabolic flights. We show that this

environment is compatible with free-fall interferometric measurements using up

to 4 second interrogation time. We present the next-generation apparatus using

degenerate gases for low release-velocity atomic sources in space-borne

experiments.

\\ ( http://arxiv.org/abs/0705.2922 , 650kb)

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arXiv:0705.2973

Date: Mon, 21 May 2007 13:17:23 GMT (255kb)

Title: Partially coherent matter wave and its evolution

Authors: Jun Chen and Qiang Lin

Categories: physics.atom-ph

Comments: 15 pages, 4 figures

\\

The evolution and propagation of a partially coherent matter wave (PCMW) is

investigated theoretically by the correlation function method. The ABCD matrix

formalism previously used for a fully coherent matter wave is extended to the

PCMW domain. A new ABCD law is derived, using a tensor method to describe the

evolution of a PCMW. An analytical solution of the first-order correlation

function is obtained that makes the propagation and evolution of a PCMW very

simple and clear. As an example, the propagation of a PCMW in a gravitational

field is calculated numerically.

\\ ( http://arxiv.org/abs/0705.2973 , 255kb)

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arXiv:0705.3036

Date: Mon, 21 May 2007 18:38:02 GMT (301kb)

Title: Feshbach resonances in ultracold K(39)

Authors: C. D'Errico, M. Zaccanti, M. Fattori, G. Roati, M. Inguscio, G.

Modugno, and A. Simoni

Categories: physics.atom-ph

Comments: 7 pages, 6 figures

\\

We discover several magnetic Feshbach resonances in collisions of ultracold

K(39) atoms, by studying atom losses and molecule formation. Accurate

determination of the magnetic-field resonance locations allows us to optimize a

quantum collision model for potassium isotopes. We employ the model to predict

the magnetic-field dependence of scattering lengths and of near-threshold

molecular levels. Our findings will be useful to plan future experiments on

ultracold potassium atoms and molecules.

\\ ( http://arxiv.org/abs/0705.3036 , 301kb)

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arXiv:0705.3093

Date: Tue, 22 May 2007 05:15:27 GMT (732kb)

Title: The Quantum de Laval Nozzle: stability and quantum dynamics of sonic

horizons in a toroidally trapped Bose gas containing a superflow

Authors: P. Jain, A. S. Bradley, C. W. Gardiner

Categories: cond-mat.other

Comments: 12 pages, 10 figures

\\

We study an experimentally realizable system containing stable black

hole-white hole acoustic horizons in toroidally trapped Bose-Einstein

condensates - the quantum de Laval nozzle. We numerically obtain stationary

flow configurations and assess their stability using Bogoliubov theory, finding

both in hydrodynamic and non-hydrodynamic regimes there exist dynamically

unstable regions associated with the creation of positive and negative energy

quasiparticle pairs in analogy with the gravitational Hawking effect. The

dynamical instability takes the form of a two mode squeezing interaction

between resonant pairs of Bogoliubov modes. We study the evolution of

dynamically unstable flows using the truncated Wigner method, which confirms

the two mode squeezed state picture of the analogue Hawking effect for low

winding number.

\\ ( http://arxiv.org/abs/0705.3093 , 732kb)

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arXiv:0705.3205

Date: Tue, 22 May 2007 16:03:54 GMT (93kb)

Title: Quantum dynamics of two bosons in an anharmonic trap: Collective vs

internal excitations

Authors: Christian Matthies, Sascha Z\"ollner, Hans-Dieter Meyer, and Peter

Schmelcher

Categories: cond-mat.other

Comments: 8 pages, 7 figures

\\

This work deals with the effects of an anharmonic trap on an interacting

two-boson system in one dimension. Our primary focus is on the role of the

induced coupling between the center of mass and the relative motion as both

anharmonicity and the (repulsive) interaction strength are varied. The ground

state reveals a strong localization in the relative coordinate, counteracting

the tendency to fragment for stronger repulsion. To explore the quantum

dynamics, we study the system's response upon (i) exciting the harmonic ground

state by continuously switching on an additional anharmonicity, and (ii)

displacing the center of mass, this way triggering collective oscillations. The

interplay between collective and internal dynamics materializes in the collapse

of oscillations, which are explained in terms of few-mode models.

\\ ( http://arxiv.org/abs/0705.3205 , 93kb)

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arXiv:0705.3155

Date: Tue, 22 May 2007 13:02:42 GMT (599kb)

Title: Observation of Topological and Parity-dependent Phase of $m=0$ Spin

States

Authors: Koji Usami and Mikio Kozuma

Categories: quant-ph

Comments: 4 pages, 4 figures

\\

A Ramsey interrogation scheme was used to measure the phase shift of

laser-cooled $^{87}$Rb clock-transition pseudospins arising as a result of a

reversal of a bias magnetic field, i.e., $\textbf{B} \to -\textbf{B}$, during

the interrogation. While no phase shift occurred when the reversal was sudden,

the Ramsey fringes were shifted by a factor of $\pi$ when the reversal was

adiabatic. We thus verified the prediction that the spin states $|F,m=0 >$

acquire a purely topological and parity-dependent phase factor of $(-1)^{F}$ as

a result of $\textbf{B} \to -\textbf{B}$.

\\ ( http://arxiv.org/abs/0705.3155 , 599kb)

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arXiv:0705.3234

Date: Tue, 22 May 2007 19:02:10 GMT (867kb)

Title: Development of an apparatus for cooling 6Li-87Rb Fermi-Bose mixtures in

a light-assisted magnetic trap

Authors: M. Brown-Hayes, Q. Wei, W.-J. Kim, and R. Onofrio

Categories: physics.atom-ph physics.optics

Comments: Presented at LPHYS'06, 8 figures

Journal-ref: Laser Physics 17 (2007) pp. 514-522

\\

We describe an experimental setup designed to produce ultracold trapped gas

clouds of fermionic 6Li and bosonic 87Rb. This combination of alkali metals has

the potential to reach deeper Fermi degeneracy with respect to other mixtures

since it allows for improved heat capacity matching which optimizes sympathetic

cooling efficiency. Atomic beams of the two species are independently produced

and then decelerated by Zeeman slowers. The slowed atoms are collected into a

magneto-optical trap and then transferred into a quadrupole magnetic trap. An

ultracold Fermi gas with temperature in the 10^-3 T_F range should be

attainable through selective confinement of the two species via a properly

detuned laser beam focused in the center of the magnetic trap.

\\ ( http://arxiv.org/abs/0705.3234 , 867kb)

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arXiv:0705.3298

Date: Wed, 23 May 2007 07:25:19 GMT (142kb)

Title: Bogoliubov spectrum of a cigar shaped Fermi superfluid in an optical

lattice at the BEC-BCS crossover

Authors: Aranya B Bhattacherjee

Categories: cond-mat.stat-mech

Comments: 7 pages, 2 figures

\\

We study the Bogoliubov spectrum of an elongated Fermi superfluid confined in

an one-dimensional superfluid along the Bose-Einstein-condensate

(BEC)-Bardeen-Cooper-Schrieffer (BCS) crossover. We derive analytic expressions

for the sound velocity, effective mass and the Bogoliubov excitation spectrum

of the axial quasiparticles long the crossover based on the hydrodynamic

theory. Our investigation reveal interesting signatures of BEC-BCS crossover in

an optical lattice which deserve experimental investigation.

\\ ( http://arxiv.org/abs/0705.3298 , 142kb)

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arXiv:0705.3341

Date: Wed, 23 May 2007 19:22:48 GMT (450kb)

Title: Hall effects in Bose-Einstein condensates in a rotating optical lattice

Authors: Rajiv Bhat, M. Kraemer, J. Cooper, M. J. Holland

Categories: cond-mat.mes-hall cond-mat.other

Comments: 11 pages, 13 figures

\\

Using the Kubo formalism, we demonstrate fractional quantum Hall features in

a rotating Bose-Einstein condensate in a co-rotating two-dimensional optical

lattice. The co-rotating lattice and trap potential allow for an effective

magnetic field and compensation of the centrifugal potential. Fractional

quantum Hall features are seen for the single-particle system and for few

strongly interacting many-particle systems.

\\ ( http://arxiv.org/abs/0705.3341 , 450kb)

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arXiv:0705.3361

Date: Wed, 23 May 2007 12:33:37 GMT (636kb)

Title: Imbalanced Superfluid Phase of a Trapped Fermi Gas in the BCS-BEC

Crossover Regime

Authors: T. Mizushima, M. Ichioka, K. Machida

Categories: cond-mat.supr-con

Comments: 16 pages, 13 figures

\\

We theoretically investigate the ground state of trapped neutral fermions

with population imbalance in the BCS-BEC crossover regime. Based on the

single-channel Hamiltonian, we perform fully numerical calculations of the

Bogoliubov-de Gennes equation coupled with the regularized gap and number

equations. The zero temperature phase diagram in the crossover regime is

presented, where the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing state

governs the weak coupling BCS region of a resonance. It is found that the FFLO

oscillation vanishes in the BEC side, in which the system under population

imbalance turns into the phase separation (PS) between locally binding

superfluid and fully polarized spin domains. We also demonstrate the numerical

calculations with a large particle number O(10^5) comparable with the recent

experiments. The resulting density profile on a resonance yields the PS which

is in good agreement with the recent experiments, while there exists the FFLO

modulation in the pairing field. It is also proposed that the most favorable

situation for the detection of the FFLO oscillation is in the vicinity of the

critical population imbalance in the weak coupling BCS regime, where the

oscillation periodicity becomes much larger than the interparticle spacing.

Finally, we analyze the radio-frequency (RF) spectroscopy in the imbalanced

system. The clear difference of the RF spectroscopy between BCS and BEC sides

reveals the structure on the pairing field and local ``magnetization''.

\\ ( http://arxiv.org/abs/0705.3361 , 636kb)

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arXiv:0705.3376

Date: Wed, 23 May 2007 13:51:46 GMT (214kb)

Title: Gaussian number-squeezed states for sub-shot-noise interferometery in

double-well Bose-Einstein condensates

Authors: Y. P. Huang and M. G. Moore

Categories: quant-ph

\\

We show that a Mach-Zender interferometer with a gaussian number-squeezed

input state can exhibit sub-shot-noise phase resolution over a large range of

measured phase-shifts in a single measurement. In contrast, previously studied

input states are shown to degrade quickly to worse than shot-noise when a

non-zero phase-shift is measured. This interferometer can be implemented in a

double-well Bose-Einstein condensate system, and the gaussian squeezed states

can obtained via adiabatic manipulation of the ground state in the presence of

repulsive atomic interactions. From Bayesian analysis, we find that the

phase-estimation uncertainty scales as 1/N at zero phase, and crosses over

smoothly to the shot-noise limit $1/\sqrt{N}$ as the phase approaches

$\pm\pi/2$.

\\ ( http://arxiv.org/abs/0705.3376 , 214kb)

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arXiv:0705.3268

Date: Wed, 23 May 2007 00:09:22 GMT (216kb)

Title: Atomtronic circuits of diodes and transistors

Authors: R. A. Pepino, J. Cooper, D. Z. Anderson & M. J. Holland

Categories: physics.atom-ph

Comments: 4 pages, 4 figures

\\

In this letter, we illustrate that open quantum systems composed of neutral,

ultracold atomic gases trapped in optical lattices can exhibit analogous

behavior to semiconductor electronic circuits. A precise, physically-attainable

correspondence is demonstrated and the experimental parameters needed to

realize the behavior of semiconductor diodes and transistors are presented. Our

analysis follows from our formulation of a modified master equation approach to

this general class of open quantum systems.

\\ ( http://arxiv.org/abs/0705.3268 , 216kb)

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arXiv:0705.3302

Date: Wed, 23 May 2007 08:28:48 GMT (63kb)

Title: Modeling many-particle mechanical effects of an interacting Rydberg gas

Authors: Thomas Amthor, Markus Reetz-Lamour, Christian Giese, and Matthias

Weidem\"{u}ller

Categories: physics.atom-ph

\\

In a recent work [Phys. Rev. Lett. 98, 023004 (2007)] we have investigated

the influence of attractive van der Waals interaction on the pair distribution

and Penning ionization dynamics of ultracold Rydberg gases. Here we extend this

description to atoms initially prepared in Rydberg states exhibiting repulsive

interaction. We present calculations based on a Monte Carlo algorithm to

simulate the dynamics of many atoms under the influence of both repulsive and

attractive longrange interatomic forces. Redistribution to nearby states

induced by black body radiation is taken into account, changing the effective

interaction potentials. The model agrees with experimental observations, where

the ionization rate is found to increase when the excitation laser is

blue-detuned from the atomic resonance.

\\ ( http://arxiv.org/abs/0705.3302 , 63kb)

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arXiv:0705.3416

Date: Wed, 23 May 2007 16:44:50 GMT (96kb)

Title: Electron Temperature Evolution in Expanding Ultracold Neutral Plasmas

Authors: P. Gupta, S. Laha, C. E. Simien, H. Gao, J. Castro, T. Pohl and T. C.

Killian

Categories: physics.atom-ph physics.plasm-ph

\\

We have used the free expansion of ultracold neutral plasmas as a

time-resolved probe of electron temperature. A combination of experimental

measurements of the ion expansion velocity and numerical simulations

characterize the crossover from an elastic-collision regime at low initial

Gamma_e, which is dominated by adiabatic cooling of the electrons, to the

regime of high Gamma_e in which inelastic processes drastically heat the

electrons. We identify the time scales and relative contributions of various

processes, and experimentally show the importance of radiative decay and

disorder-induced electron heating for the first time in ultracold neutral

plasmas.

\\ ( http://arxiv.org/abs/0705.3416 , 96kb)

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arXiv:0705.3442

Date: Wed, 23 May 2007 18:49:18 GMT (663kb,D)

Title: Mitigation of loss within a molecular Stark decelerator

Authors: Brian C. Sawyer, Benjamin K. Stuhl, Benjamin L. Lev, Eric R. Hudson,

and Jun Ye

Categories: physics.atom-ph physics.atm-clus

Comments: 13 pages, 17 figures

\\

The transverse motion inside a Stark decelerator plays a large role in the

total efficiency of deceleration. We differentiate between two separate regimes

of molecule loss during the slowing process. The first mechanism involves

distributed loss due to coupling of transverse and longitudinal motion, while

the second is a result of the rapid decrease of the molecular velocity within

the final few stages. In this work, we describe these effects and present means

for overcoming them. Solutions based on modified switching time sequences with

the existing decelerator geometry lead to a large gain of stable molecules in

the intermediate velocity regime, but fail to address the loss at very low

final velocities. We propose a new decelerator design, the quadrupole-guiding

decelerator, which eliminates distributed loss due to transverse/longitudinal

couplings throughout the slowing process and also exhibits gain over normal

deceleration to the lowest velocities.

\\ ( http://arxiv.org/abs/0705.3442 , 663kb)

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arXiv:0705.3454

Date: Wed, 23 May 2007 23:33:10 GMT (551kb)

Title: Engineering fidelity echoes in Bose-Hubbard Hamiltonians

Authors: J.D. Bodyfelt, M. Hiller and T. Kottos

Categories: cond-mat.other

Comments: 6 pages, use epl2.cls class, 5 figures Cross reference with nlin,

quant-phys

Journal-ref: EPL 78 (2007) 50003

DOI: 10.1209/0295-5075/78/50003

\\

We analyze the fidelity decay for a system of interacting bosons described by

a Bose-Hubbard Hamiltonian. We find echoes associated with "non-universal"

structures that dominate the energy landscape of the perturbation operator.

Despite their classical origin, these echoes persist deep into the quantum

(perturbative) regime and can be described by an improved random matrix

modeling. In the opposite limit of strong perturbations (and high enough

energies), classical considerations reveal the importance of self-trapping

phenomena in the echo efficiency.

\\ ( http://arxiv.org/abs/0705.3454 , 551kb)

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arXiv:0705.3569

Date: Thu, 24 May 2007 16:31:53 GMT (15kb)

Title: A note on the spin-1/2 XXZ chain concerning its relation to the Bose gas

Authors: Alexander Seel, Tanaya Bhattacharyya, Frank G\"{o}hmann, Andreas

Kl\"{u}mper

Categories: cond-mat.stat-mech

Comments: 12 pages, 1 figure

\\

By considering the one-particle and two-particle scattering data of the

spin-1/2 Heisenberg chain at T=0 we derive a continuum limit relating the spin

chain to the 1D Bose gas. Applying this limit to the quantum transfer matrix

approach of the Heisenberg chain we obtain expressions for the correlation

functions of the Bose gas at arbitrary temperatures.

\\ ( http://arxiv.org/abs/0705.3569 , 15kb)

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arXiv:0705.3456

Date: Thu, 24 May 2007 18:50:48 GMT (402kb)

Title: Unifying variational methods for simulating quantum many-body systems

Authors: Christopher M. Dawson, Jens Eisert, Tobias J. Osborne

Categories: quant-ph

Comments: 5 pages, 3 figures

\\

We introduce a unified formulation of variational methods for simulating

ground state properties of quantum many-body systems. The key feature is a

novel variational method over quantum circuits via infinitesimal unitary

transformations, inspired by flow equation methods. This gives rise to a

unifying picture of several existing variational techniques for simulating

strongly correlated systems: variational classes are represented as efficiently

contractible unitary networks, including, the matrix-product states of density

matrix renormalization (DMRG), multiscale entanglement renormalization (MERA)

states, weighted graph states, quantum cellular automata, and others. In

particular, this provides a tool for varying over classes of states, such as

MERA, for which so far no efficient way of variation is known, including

two-dimensional systems. The scheme is flexible when it comes to hybridizing

existing methods or formulating new ones. We demonstrate the functioning of the

formalism by a numerical implementation.

\\ ( http://arxiv.org/abs/0705.3456 , 402kb)

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arXiv:0705.3477

Date: Wed, 23 May 2007 22:21:40 GMT (129kb)

Title: Vacuum Fluctuations induced Entanglement between Two Mesoscopic Systems

Authors: H. T. Ng and K. Burnett

Categories: quant-ph

Comments: 4 pages, 4 figures

\\

We study the dynamics of a pair of molecular ensembles trapped inside a

superconducting resonator through which they are strongly coupled via a

microwave field mode. We find that entanglement can be generated via ``vacuum

fluctuations'' even when the molecules and cavity field are initially prepared

in their ground state. This entanglement is created in a relatively short time

and without the need for further manipulation of the system. It does,

therefore, provide a convenient scheme to entangle two mesoscopic systems, and

may well be useful quantum information processing.

\\ ( http://arxiv.org/abs/0705.3477 , 129kb)

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arXiv:0705.3491

Date: Thu, 24 May 2007 01:13:23 GMT (9kb)

Title: Opposite sign correlations in fermion or boson gases

Authors: Alex D. Gottlieb, Thorsten Schumm

Categories: quant-ph

\\

We investigate pair correlations in trapped fermion and boson gases as a

means to probe the quantum states producing the density fluctuations. We point

out that "opposite sign correlations" (meaning pair correlations that are

positive for fermions and negative for bosons) unambiguously indicate that the

quantum many-particle state cannot be "free." In particular, a system of

fermions that exhibits positive pair correlations cannot be described by any

Slater determinant wavefunction. This insight may help one to interpret results

of current experiments on ultracold atomic gases.

\\ ( http://arxiv.org/abs/0705.3491 , 9kb)

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arXiv:0705.3506

Date: Thu, 24 May 2007 04:48:45 GMT (145kb,D)

Title: Entangled-State Cycles of Atomic Collective-Spin States

Authors: A. Chia and A. S. Parkins

Categories: quant-ph

Comments: 10 pages, 9 figures

\\

We study quantum trajectories of collective atomic spin states of $N$

effective two-level atoms driven with laser and cavity fields. We show that

interesting ``entangled-state cycles'' arise probabilistically when the (Raman)

transition rates between the two atomic levels are set equal. For odd (even)

$N$, there are $(N+1)/2$ ($N/2$) possible cycles. During each cycle the

$N$-qubit state switches, with each cavity photon emission, between the states

$(|N/2,m>\pm |N/2,-m>)/\sqrt{2}$, where $|N/2,m>$ is a Dicke state in a rotated

collective basis. The quantum number $m$ ($>0$), which distinguishes the

particular cycle, is determined by the photon counting record and varies

randomly from one trajectory to the next. For even $N$ it is also possible,

under the same conditions, to prepare probabilistically (but in steady state)

the Dicke state $|N/2,0>$, i.e., an $N$-qubit state with $N/2$ excitations,

which is of particular interest in the context of multipartite entanglement.

\\ ( http://arxiv.org/abs/0705.3506 , 145kb)

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\\

arXiv:0705.3639

Date: Thu, 24 May 2007 19:06:21 GMT (510kb,D)

Title: Prospects for the cavity-assisted laser cooling of molecules

Authors: Benjamin L. Lev, Andras Vukics, Eric R. Hudson, Brian C. Sawyer, Peter

Domokos, Helmut Ritsch, and Jun Ye

Categories: quant-ph

Comments: 18 pages, 10 figures

\\

Cooling of molecules via free-space dissipative scattering of photons is

thought not to be practicable due to the inherently large number of Raman loss

channels available to molecules and the prohibitive expense of building

multiple repumping laser systems. The use of an optical cavity to enhance

coherent Rayleigh scattering into a decaying cavity mode has been suggested as

a potential method to mitigate Raman loss, thereby enabling the laser cooling

of molecules to ultracold temperatures. We discuss the possibility of

cavity-assisted laser cooling particles without closed transitions, identify

conditions necessary to achieve efficient cooling, and suggest solutions given

experimental constraints. Specifically, it is shown that cooperativities much

greater than unity are required for cooling without loss, and that this could

be achieved via the superradiant scattering associated with intracavity

self-localization of the molecules. Particular emphasis is given to the polar

hydroxyl radical (OH), cold samples of which are readily obtained from Stark

deceleration.

\\ ( http://arxiv.org/abs/0705.3639 , 510kb)

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The replacments:

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arXiv:cond-mat/0205210

replaced with revised version Fri, 18 May 2007 15:32:40 GMT (25kb)

Title: Stability of the two-dimensional Bose gases in the resonant regime

Authors: Ludovic Pricoupenko and Maxim Olshanii

Categories: cond-mat

Comments: 6 pages, latex, 2 figures

Journal-ref: J. Phys. B: At. Mol. Opt. Phys. 40 (2007) 2065-2074

DOI: 10.1088/0953-4075/40/11/009

\\ ( http://arxiv.org/abs/cond-mat/0205210 , 25kb)

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\\

arXiv:cond-mat/0506264

replaced with revised version Fri, 18 May 2007 02:03:36 GMT (45kb)

Title: Exact results for the 1D interacting Fermi gas with arbitrary

polarization

Authors: M.T. Batchelor, M. Bortz, X.W. Guan and N. Oelkers

Categories: cond-mat.str-el cond-mat.stat-mech

Comments: 7 pages, 3 figures, final published version without the discussion of

harmonic trapping (to be taken up elsewhere). The effect of a magnetic-like

field term on pairing and phase transtions has been discussed via the TBA

approach in cond-mat/0702191

Journal-ref: J. Phys. Conf. Ser. 42 (2006) 5

DOI: 10.1088/1742-6596/42/1/002

\\ ( http://arxiv.org/abs/cond-mat/0506264 , 45kb)

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\\

arXiv:cond-mat/0701058

replaced with revised version Fri, 18 May 2007 15:14:57 GMT (9kb)

Title: Decoherence Dynamics in Low-Dimensional Cold Atom Interferometers

Authors: A.A. Burkov, M.D. Lukin, Eugene Demler

Categories: cond-mat.supr-con cond-mat.str-el

Comments: 4 pages, published version

Journal-ref: Phys. Rev. Lett. 98, 200404 (2007)

DOI: 10.1103/PhysRevLett.98.200404

\\ ( http://arxiv.org/abs/cond-mat/0701058 , 9kb)

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\\

arXiv:0704.1995

replaced with revised version Sat, 19 May 2007 08:40:29 GMT (85kb)

Title: Coherent dynamics of domain formation in the Bose Ferromagnet

Authors: Qiang Gu, Haibo Qiu

Categories: cond-mat.other cond-mat.stat-mech

Comments: 4 pages, 3 figures

Journal-ref: Phys. Rev. Lett. 98, 200401 (2007)

\\ ( http://arxiv.org/abs/0704.1995 , 85kb)

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\\

arXiv:cond-mat/0608585

replaced with revised version Sat, 19 May 2007 16:47:29 GMT (936kb)

Title: Long Phase Coherence Time and Number Squeezing of two Bose-Einstein

Condensates on an Atom Chip

Authors: G.-B. Jo, Y. Shin, S. Will, T. A. Pasquini, M. Saba, W. Ketterle, D.

E. Pritchard, M. Vengalattore, and M. Prentiss

Categories: cond-mat.other

Comments: 5 pages, 5 figures

Journal-ref: Phy. Rev. Lett. 98, 030407 (2007)

DOI: 10.1103/PhysRevLett.98.030407

\\ ( http://arxiv.org/abs/cond-mat/0608585 , 936kb)

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arXiv:cond-mat/0703006

replaced with revised version Sat, 19 May 2007 16:34:45 GMT (869kb)

Title: Phase Sensitive Recombination of Two Bose-Einstein Condensates on an

Atom Chip

Authors: G.-B. Jo, J.-H. Choi, C.A. Christensen, T.A. Pasquini, Y.-R. Lee, W.

Ketterle, and D.E. Pritchard

Categories: cond-mat.other

Comments: 5 pages, 4 figures

Journal-ref: Phys. Rev. Lett. 98, 180401 (2007)

DOI: 10.1103/PhysRevLett.98.180401

\\ ( http://arxiv.org/abs/cond-mat/0703006 , 869kb)

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arXiv:cond-mat/0601148

replaced with revised version Tue, 22 May 2007 02:30:31 GMT (56kb)

Title: Surface Energy in Cold Asymmetrical Fermion Superfluids

Authors: Heron Caldas

Categories: cond-mat.supr-con astro-ph cond-mat.str-el hep-ph nucl-th

Comments: 12 pages, 2 figures, expanded version, typos corrected, references

added

\\ ( http://arxiv.org/abs/cond-mat/0601148 , 56kb)

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arXiv:cond-mat/0703805

replaced with revised version Tue, 22 May 2007 04:13:57 GMT (87kb)

Title: Multicomponent Bright Solitons in F = 2 Spinor Bose-Einstein Condensates

Authors: Masaru Uchiyama, Jun'ichi Ieda, Miki Wadati

Categories: cond-mat.other nlin.SI

Comments: 15 pages, 8 figures

\\ ( http://arxiv.org/abs/cond-mat/0703805 , 87kb)

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arXiv:cond-mat/0412269

replaced with revised version Wed, 23 May 2007 12:20:26 GMT (26kb)

Title: Density correlations in ultracold atomic Fermi gases

Authors: W. Belzig, C. Schroll, and C. Bruder

Categories: cond-mat.supr-con cond-mat.mes-hall

Comments: 4 pages, 4 figures. To appear in Phys. Rev. A. New calculation of the

bin statistics of a free Bose gas; updated and extended bibliography

\\ ( http://arxiv.org/abs/cond-mat/0412269 , 26kb)

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\\

arXiv:cond-mat/0601148

replaced with revised version Tue, 22 May 2007 20:51:36 GMT (56kb)

Title: Surface Energy in Cold Asymmetrical Fermion Superfluids

Authors: Heron Caldas

Categories: cond-mat.supr-con astro-ph cond-mat.str-el hep-ph nucl-th

Comments: 12 pages, 2 figures, expanded version, typos corrected, references

added

\\ ( http://arxiv.org/abs/cond-mat/0601148 , 56kb)

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\\

arXiv:cond-mat/0612498

replaced with revised version Wed, 23 May 2007 10:13:20 GMT (90kb)

Title: Metastable states of a gas of dipolar bosons in a 2D optical lattice

Authors: C. Menotti, C. Trefzger, and M. Lewenstein

Categories: cond-mat.other cond-mat.dis-nn

Comments: small improvements in the text, Fig.4 replaced, added and updated

references. 4 pages, 4 figures, to appear in Phys. Rev. Lett

\\ ( http://arxiv.org/abs/cond-mat/0612498 , 90kb)

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arXiv:cond-mat/0612670

replaced with revised version Wed, 23 May 2007 18:52:38 GMT (29kb)

Title: Anderson Localization of Expanding Bose-Einstein Condensates in Random

Potentials

Authors: Laurent Sanchez-Palencia (LCFIO), David Cl\'ement (LCFIO), Pierre

Lugan (LCFIO), Philippe Bouyer (LCFIO), Georgy V. Shlyapnikov (LPTMS), Alain

Aspect (LCFIO)

Categories: cond-mat.other

Comments: published versioon (no significant change compared to last version)

Journal-ref: Physical Review Letters 98 (2007) 210401

DOI: 10.1103/PhysRevLett.98.210401

\\ ( http://arxiv.org/abs/cond-mat/0612670 , 29kb)

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arXiv:quant-ph/0609119

replaced with revised version Tue, 22 May 2007 22:05:01 GMT (568kb)

Title: Ultracold Bosons in a Tilted Multi-level Double-Well Potential

Authors: D. R. Dounas-Frazer, A. M. Hermundstad, and L. D. Carr

Categories: quant-ph cond-mat.other

Comments: 4 pages, 3 figures

\\ ( http://arxiv.org/abs/quant-ph/0609119 , 568kb)

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\\

arXiv:cond-mat/0604424

replaced with revised version Thu, 24 May 2007 19:27:15 GMT (121kb)

Title: Non-BCS superfluidity in trapped ultracold Fermi gases

Authors: L. M. Jensen, J. Kinnunen, and P. Torma

Categories: cond-mat.str-el cond-mat.other

Comments: Extended and revised, 13 pages, 13 figures

\\ ( http://arxiv.org/abs/cond-mat/0604424 , 121kb)

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arXiv:cond-mat/0612302

replaced with revised version Thu, 24 May 2007 18:00:10 GMT (94kb)

Title: Edge Transport in 2D Cold Atom Optical Lattices

Authors: V.W. Scarola and S. Das Sarma

Categories: cond-mat.other quant-ph

Journal-ref: Phys. Rev. Lett. 98, 210403 (2007)

\\ ( http://arxiv.org/abs/cond-mat/0612302 , 94kb)

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arXiv:physics/0612143

replaced with revised version Thu, 24 May 2007 11:39:56 GMT (138kb)

Title: Dynamical interferences to probe short-pulse photoassociation of Rb

atoms and stabilization of Rb_2 dimers

Authors: Jordi Mur-Petit, Eliane Luc-Koenig, Francoise Masnou-Seeuws

Categories: physics.atom-ph cond-mat.other quant-ph

Comments: 4 pages, 5 figures. v2: major changes in introduction, discussion

clarified. v3: minor corrections, version accepted for publication in Phys.

Rev. A (Rapid Comm.)

\\ ( http://arxiv.org/abs/physics/0612143 , 138kb)

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Till next time,

Matt.

-- ========================================================================= Dr M. J. Davis, Senior Lecturer in Physics School of Physical Sciences, email: mdavis_at_physics.uq.edu.au University of Queensland, ph : +61 7 334 69824 Brisbane, QLD 4072, fax : +61 7 336 51242 Australia. http://www.physics.uq.edu.au/people/mdavis/ ========================================================================= Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/ ========================================================================= Legal stuff: Unless stated otherwise, this e-mail represents only the views of the sender and not the views of the University of Queensland =========================================================================Received on Wed Jun 06 2007 - 01:57:30 EST

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