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

Date: Thu, 15 Jul 2010 14:06:53 +1000

Date: Thu, 15 Jul 2010 14:06:53 +1000

Dear subscribers,

This week's selection was compiled by Geoff Lee, and contains 38 new

abstracts and 9 replacements.

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arXiv:0912.1305 (*cross-listing*)

Date: Mon, 7 Dec 2009 18:53:47 GMT (242kb)

Date (revised v2): Fri, 11 Jun 2010 08:23:19 GMT (619kb,D)

Title: Vortex entanglement in Bose-Einstein condensates coupled to

Laguerre-Gauss beams

Authors: N. Lo Gullo, S. McEndoo, Th. Busch, M. Paternostro

Categories: cond-mat.quant-gas quant-ph

Comments: 10 pages, 7 figures, RevTex4

Journal-ref: Phys. Rev. A 81, 053625 (2010)

\\

We study the establishment of vortex entanglement in remote and weakly

interacting Bose Einstein condensates. We consider a two-mode photonic resource

entangled in its orbital angular momentum (OAM) degree of freedom and, by

exploiting the process of light-to-BEC OAM transfer, demonstrate that such

entanglement can be efficiently passed to the matter-like systems. Our proposal

thus represents a building block for novel low-dissipation and long-memory

communication channels based on OAM. We discuss issues of practical

realizability, stressing the feasibility of our scheme and present an operative

technique for the indirect inference of the set vortex entanglement.

\\ ( http://arxiv.org/abs/0912.1305 , 619kb)

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arXiv:1006.2160 (*cross-listing*)

Date: Thu, 10 Jun 2010 22:00:44 GMT (188kb,D)

Title: Many-Body Rate Limit on Photoassociation of a Bose-Einstein Condensate

Authors: Matt Mackie and Pierre Phou

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

Comments: 4 pages, 3 figures, 58 references, submitted to PRA as Brief Report

\\

We briefly report on zero-temperature photoassociation of a Bose-Einstein

condensate, focusing on the many-body rate limit for atom-molecule conversion.

An upgraded model that explicitly includes spontaneous radiative decay leads to

an unanticipated shift in the position of the photoassociation resonance, which

affects whether the rate (constant) maximizes or saturates, as well as the

limiting value itself. A simple analytical model agrees with numerical

experiments, but only for high density. Finally, an explicit comparison with

the two-body unitary limit, set by the size of the condensate, finds that the

many-body rate limit is generally more strict.

\\ ( http://arxiv.org/abs/1006.2160 , 188kb)

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arXiv:1006.2161

Date: Thu, 10 Jun 2010 22:15:57 GMT (346kb)

Title: Exact results on the two-particle Green's function of a Bose-Einstein

condensate

Authors: Takafumi Kita

Categories: cond-mat.quant-gas cond-mat.stat-mech cond-mat.supr-con nucl-th

Comments: 5 pages, 2 figures, to appear in Phys. Rev. B

\\

Starting from the Dyson-Beliaev and generalized Gross-Pitaevskii equations

with an extra nonlocal potential, we derive an exact expression of the

two-particle Green's function K for an interacting Bose-Einstein condensate in

terms of unambiguously defined self-energies and vertices. The formula can be a

convenient basis for approximate calculations of K. It also tells us that poles

of K are not shared with (i.e. shifted from) those of the single-particle

Green's function, contrary to the conclusion of previous studies.

\\ ( http://arxiv.org/abs/1006.2161 , 346kb)

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arXiv:1006.2241

Date: Fri, 11 Jun 2010 09:44:32 GMT (127kb,D)

Title: Radio Frequency Association of Efimov Trimers

Authors: Thomas Lompe, Timo B. Ottenstein, Friedhelm Serwane, Andre N. Wenz,

Gerhard Z\"urn and Selim Jochim

Categories: cond-mat.quant-gas

Comments: 14 pages, 6 figures

\\

The quantum-mechanical three-body problem is one of the fundamental

challenges of few-body physics. It becomes particularly interesting if the

two-body interactions between the particles become resonant. In 1970 V. Efimov

predicted that such systems can exhibit an infinite series of universal

three-body bound states whose properties are determined by the strength of the

two-body interactions. Here we report on the direct observation of such an

Efimov state with radio frequency (RF) association spectroscopy. We have

measured its binding energy as a function of interaction strength and found

good agreement with theoretical predictions. With this work both precision

studies and coherent manipulation of Efimov trimers have come into experimental

reach.

\\ ( http://arxiv.org/abs/1006.2241 , 127kb)

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arXiv:1006.2261

Date: Fri, 11 Jun 2010 11:21:43 GMT (2528kb)

Title: Magnetic Richtmyer-Meshkov instability in a two-component Bose-Einstein

condensate

Authors: A. Bezett, V. Bychkov, E. Lundh, D. Kobyakov, M. Marklund

Categories: cond-mat.quant-gas

Comments: 8 pages, 9 figures

\\

The magnetically induced Richtmyer-Meshkov instability in a two-component

Bose-Einstein condensate is investigated. We construct and study analytical

models describing the development of the instability at both the linear and

nonlinear stages. The models indicate new features of the instability: the

influence of quantum capillary waves and the separation of droplets, which are

qualitatively different from the classical case. We perform numerical

simulations of the instability in a trapped Bose-Einstein condensate using the

Gross-Pitaevskii equation and compare the simulation results to the model

predictions.

\\ ( http://arxiv.org/abs/1006.2261 , 2528kb)

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arXiv:1006.2267

Date: Fri, 11 Jun 2010 11:42:44 GMT (40kb)

Title: Nielsen-Olesen string field theory and the Abelian-Higgs duality in 3+1

and higher dimensions

Authors: A.J. Beekman, D. Sadri and J. Zaanen

Categories: cond-mat.str-el hep-th

Comments: RevTeX, 12 pages, 4 figures

\\

The Abelian-Higgs (or vortex, XY) duality in 2+1 dimensions demonstrates that

the quantum disordered superfluid is equivalent to an ordered superconductor

and the other way around. Such a duality structure should be ubiquitous but in

3+1 (and higher) dimensions a precise formulation of the duality is lacking.

The problem is that the topological defects become extended objects, strings in

3+1D. We argue how the condensate of such vortex strings must behave from the

known physics of the disordered superfluid, namely the Bose-Mott insulator. A

flaw in earlier proposals is repaired, and a more direct viewpoint, avoiding

gauge fields, in terms of the physical supercurrent is laid out, that also

easily generalizes to higher-dimensional and more complicated systems.

\\ ( http://arxiv.org/abs/1006.2267 , 40kb)

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arXiv:1006.2324

Date: Fri, 11 Jun 2010 14:43:22 GMT (229kb)

Title: Self-localization of a small number of Bose particles in a superfluid

Fermi system

Authors: Krzysztof Sacha, Katarzyna Targo\'nska

Categories: cond-mat.quant-gas

Comments: 7 pages, 7 fiqures

\\

We consider self-localization of a small number of Bose particles immersed in

a large homogeneous superfluid mixture of fermions in three and one dimensional

spaces. Bosons the distort density of surrounding fermions and create a

potential well where they can form a bound state analogous to a small polaron

state. In the three dimensional volume we observe the self-localization for

repulsive interactions between bosons and fermions. In the one dimensional case

bosons self-localize as well as for attractive interactions forming, together

with a pair of fermions at the bottom of the Fermi sea, a vector soliton. We

analyze also thermal effects and show that small non-zero temperature affects

the pairing function of the Fermi-subsystem and has little influence on the

self-localization phenomena.

\\ ( http://arxiv.org/abs/1006.2324 , 229kb)

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arXiv:1006.2358

Date: Fri, 11 Jun 2010 18:10:41 GMT (227kb)

Title: Atomic Bloch-Zener Oscillations and St\"uckelberg Interferometry in

Optical Lattices

Authors: Sebastian Kling, Tobias Salger, Christopher Grossert, and Martin Weitz

Categories: cond-mat.quant-gas

\\

We report on experiments investigating quantum transport and band

interferometry of an atomic Bose-Einstein condensate in an optical lattice with

a two-band miniband structure, realized with a Fourier-synthesized optical

lattice potential. Bloch-Zener oscillations, the coherent superposition of

Bloch oscillations and Landau-Zener tunneling between the two bands are

observed. When the relative phase between paths in different bands is varied,

an interference signal is observed, demonstrating the coherence of the dynamics

in the miniband system. Measured fringe patterns of this St\"uckelberg

interferometer allow to interferometrically map out the band structure of the

optical lattice over the full Brillouin zone.

\\ ( http://arxiv.org/abs/1006.2358 , 227kb)

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arXiv:1006.2393

Date: Fri, 11 Jun 2010 20:12:28 GMT (81kb,D)

Title: Efimov Physics in Atom-Dimer Scattering of Lithium-6 Atoms

Authors: H.-W. Hammer, Daekyoung Kang and Lucas Platter

Categories: cond-mat.quant-gas nucl-th

Comments: 13 pages, 5 figures

Report-no: HISKP-TH-10-14, INT-PUB-10-024

\\

Lithium-6 atoms in the three lowest hyperfine states display universal

properties when the S-wave scattering length between each pair of states is

large. Recent experiments reported four pronounced features arising from Efimov

physics in the atom-dimer relaxation rate, namely two resonances and two local

minima. We use the universal effective field theory to calculate the atom-dimer

relaxation rate at zero temperature. Our results describe the four features

qualitatively and imply there is a hidden local minimum. In the vicinity of the

resonance at 685 G, we perform a finite temperature calculation which improves

the agreement of theory and experiment. We conclude that finite temperature

effects cannot be neglected in the analysis of the experimental data.

\\ ( http://arxiv.org/abs/1006.2393 , 81kb)

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arXiv:1006.2548 (*cross-listing*)

Date: Sun, 13 Jun 2010 17:17:15 GMT (274kb)

Title: Fermion Condensate and Vacuum Current Density Induced by Homogeneous and

Inhomogeneous Magnetic Fields in (2+1)-Dimensions

Authors: Alfredo Raya and Edward Reyes

Categories: hep-ph cond-mat.supr-con hep-th math-ph math.MP

Comments: 8 pages, 2 figures. Accepted for publication in Phys. Rev. D

\\

We calculate the condensate and the vacuum current density induced by

external static magnetic fields in (2+1)-dimensions. At the perturbative level,

we consider an exponentially decaying magnetic field along one cartesian

coordinate. Non-perturbatively, we obtain the fermion propagator in the

presence of a uniform magnetic field by solving the Schwinger-Dyson equation in

the rainbow-ladder approximation. In the large flux limit, we observe that both

these quantities, either perturbative (inhomogeneous) and non-perturbative

(homogeneous), are proportional to the external field, in agreement with early

expectations.

\\ ( http://arxiv.org/abs/1006.2548 , 274kb)

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arXiv:1006.2556 (*cross-listing*)

Date: Sun, 13 Jun 2010 19:33:44 GMT (326kb)

Title: Dynamical studies of macroscopic superposition states: Phase engineering

of novel controlled entangled number states of the gaseous atomic

Bose-Einstein condensate in multiple wells

Authors: Mary Ann Leung, Khan W. Mahmud, William P. Reinhardt

Categories: cond-mat.quant-gas quant-ph

Comments: 9 pages, 11 figures

\\

We provide a scheme for the generation of entangled number states of

Bose-Einstein condensates in multiple wells with cyclic pairwise connectivity.

The condensate ground state in a multiple well trap can self-evolve, when phase

engineered with specific initial phase differences between the neighboring

wells, to a state with controllable entanglement. We demonstrate through

numerical simulations the creation of entangled states in three and four wells

and then explore the creation of "larger" entangled states where there are

either a larger number of particles in each well or a larger number of wells.

The type of entanglement produced as the particle numbers, or interaction

strength, increases changes in a novel and initially unexpected manner.

\\ ( http://arxiv.org/abs/1006.2556 , 326kb)

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arXiv:1006.2645

Date: Mon, 14 Jun 2010 09:22:35 GMT (4329kb)

Title: Macroscopic Rabi-Like Oscillations of Ultracold Atoms in an Asymmetrical

Two-Dimensional Magnetic Lattice

Authors: A. Abdelrahman, M. Vasiliev and K. Alameh

Categories: quant-ph cond-mat.quant-gas

\\

We investigate the existence of the $macroscopic$ $quantum$ $phase$ in

trapped ultracold quantum degenerate gases, such as Bose-Einstein condensate,

in an asymmetrical two-dimensional magnetic lattice. We show the key to

adiabatically control the tunneling in the new two-dimensional magnetic lattice

by means of external magnetic bias fields. The macroscopic quantum phase

signature is identified as a Rabi-like oscillation when solving the system of

coupled time-dependent differential equations, described here by the Boson

Josephson Junctions (BJJs). In solving the system of the BJJs we used an order

parameter that includes both time-dependent variational parameters which are

the fractional population at each lattice site and the phase difference. The

BJJs solution presents a clear evidence for the macroscopic quantum coherence.

\\ ( http://arxiv.org/abs/1006.2645 , 4329kb)

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arXiv:1006.2646 (*cross-listing*)

Date: Mon, 14 Jun 2010 09:24:21 GMT (81kb)

Title: Crossover in the Efimov spectrum

Authors: Ludovic Pricoupenko (LPTMC)

Categories: cond-mat.quant-gas quant-ph

Comments:

\\

A filtering method is introduced for solving the zero-range three-boson

problem. This scheme allows one to solve the original Skorniakov and Ter

Martirosian integral equation for an arbitrary large Ultra-Violet cut-off and

to avoid the Thomas collapse of the three particles. The method is applied to a

more general zero-range model including a finite background two-body scattering

length and the effective range. A cross-over in the Efimov spectrum is found in

such systems and a specific regime emerges where Efimov states are long-lived.

\\ ( http://arxiv.org/abs/1006.2646 , 81kb)

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arXiv:1006.2657

Date: Mon, 14 Jun 2010 10:14:45 GMT (5kb)

Title: Weak Equivalence Principle and Propagation of the Wave Function in

Quantum Mechanics

Authors: Clovis Jacinto de Matos

Categories: physics.gen-ph quant-ph

Comments: 3 pages

\\

The propagation of the wave function of a particle is characterised by a

group and a phase velocity. The group velocity is associated with the

particle's classical velocity, which is always smaller than the speed of light,

and the phase velocity is associated with the propagation speed of the wave

function phase and is treated as being unphysical, since its value is always

greater than the speed of light. Here we show, using Sciama's Machian

formulation of rest mass energy, that this physical interpretation, for the

group and the phase velocity of the wave function, is only valid if the weak

equivalence principle strictly holds for the propagating particle, except for

the photon. In case this constraint is released the phase velocity of the wave

function could acquire a physical meaning in quantum condensates.

\\ ( http://arxiv.org/abs/1006.2657 , 5kb)

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arXiv:1006.2716 (*cross-listing*)

Date: Mon, 14 Jun 2010 14:04:45 GMT (861kb)

Title: Quantum Monte Carlo simulations of antiferromagnetism in ultracold

fermions on optical lattices within real-space dynamical mean-field theory

Authors: N. Bl\"umer and E. V. Gorelik

Categories: cond-mat.quant-gas physics.comp-ph

Comments: 4 pages, 4 figures; proceedings of the Conference on Computational

Physics 2009

\\

We present a massively parallel quantum Monte Carlo based implementation of

real-space dynamical mean-field theory for general inhomogeneous correlated

fermionic lattice systems. As a first application, we study magnetic order in a

binary mixture of repulsively interacting fermionic atoms harmonically trapped

in an optical lattice. We explore temperature effects and establish signatures

of the N\'{e}el transition in observables directly accessible in cold-atom

experiments; entropy estimates are also provided. We demonstrate that the local

density approximation (LDA) fails for ordered phases. In contrast, a "slab"

approximation allows us to reach experimental system sizes with O(10^5) atoms

without significant loss of accuracy.

\\ ( http://arxiv.org/abs/1006.2716 , 861kb)

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arXiv:1006.2922

Date: Tue, 15 Jun 2010 08:38:31 GMT (596kb)

Title: Dynamics of Vortices and Solitons in a Bose-Einstein Condensate by an

Oscillating Potential

Authors: Kazuya Fujimoto and Makoto Tsubota

Categories: cond-mat.quant-gas

Comments: 8 pages, 6 figure

\\

We study numerically the dynamics of quantized vortices and solitons induced

by an oscillating potential inside a trapped Bose-Einstein condensate. The

dynamics of the topological defects is much different from the case for a

linear uniform object; the metamorphosis between vortices and solitons is

characteristic of the dynamics. We discuss how vortices are nucleated by an

oscillating potential.

\\ ( http://arxiv.org/abs/1006.2922 , 596kb)

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arXiv:1006.2934

Date: Tue, 15 Jun 2010 09:30:20 GMT (344kb)

Title: Fractalization and emission of vortex rings in the Kelvin waves cascade

Authors: Andrew W. Baggaley, Carlo F. Barenghi

Categories: cond-mat.stat-mech physics.flu-dyn

Comments: 18 pages, 12 figures

\\

We report results of numerical simulations of the time evolution of quantized

vortex filaments following a vortex reconnection. We study the resulting Kelvin

waves cascade and compare the amplitude spectrum with existing theories and

numerical calculations. We show that the vortex filaments become fractal, and

that large-amplitude twisting of the filaments leads to secondary reconnections

and the emission of small vortex rings.

\\ ( http://arxiv.org/abs/1006.2934 , 344kb)

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arXiv:1006.2954 (*cross-listing*)

Date: Tue, 15 Jun 2010 10:46:21 GMT (960kb)

Title: Particle-Localized Ground State of Atom-Molecule Bose-Einstein

Condensates in a Double-Well Potential

Authors: Atsushi Motohashi and Tetsuro Nikuni

Categories: cond-mat.quant-gas quant-ph

Comments: 34 pages,10 figures

\\

We study the effect of atom-molecule internal tunneling on the ground state

of atom-molecule Bose-Einstein condensates in a double-well potential. In the

absence of internal tunneling between atomic and molecular states, the ground

state is symmetric, which has equal-particle populations in two wells. From the

linear stability analysis, we show that the symmetric stationary state becomes

dynamically unstable at a certain value of the atom-molecule internal tunneling

strength. Above the critical value of the internal tunneling strength, the

ground state bifurcates to the particle-localized ground states. The origin of

this transition can be attributed to the effective attractive inter-atomic

interaction induced by the atom-molecule internal tunneling. This effective

interaction is similar to that familiar in the context of BCS-BEC crossover in

a Fermi gas with Feshbach resonance. Furthermore, we point out the possibility

of reentrant transition in the case of the large detuning between the atomic

and molecular states.

\\ ( http://arxiv.org/abs/1006.2954 , 960kb)

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arXiv:1006.2962

Date: Tue, 15 Jun 2010 11:21:41 GMT (1325kb)

Title: Rotonlike instability and pattern formation in spinor Bose-Einstein

condensates

Authors: Michal Matuszewski

Categories: cond-mat.quant-gas

\\

We show that metastable phases of an antiferromagnetic spin-1 condensate in a

simple model with pure contact interactions can exhibit a rotonlike minimum in

the excitation spectrum. The introduction of magnetic field gives rise to the

instability of roton modes, which can lead to spontaneous emergence of regular

periodic, polygonal, polyhedral or crystalline patterns, as shown in numerical

simulations within the truncated Wigner approximation. An explanation of the

occurrence of rotonlike instability is given based on the energy and spin

conservation laws.

\\ ( http://arxiv.org/abs/1006.2962 , 1325kb)

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arXiv:1006.2975 (*cross-listing*)

Date: Tue, 15 Jun 2010 12:40:56 GMT (241kb,D)

Title: Cold atom simulation of interacting relativistic quantum field theories

Authors: J. Ignacio Cirac, Paolo Maraner and Jiannis K. Pachos

Categories: cond-mat.str-el hep-lat quant-ph

Comments: 4 pages, 3 figues

\\

We demonstrate that Dirac fermions self-interacting or coupled to dynamic

scalar fields can emerge in the low energy sector of designed bosonic and

fermionic cold atom systems. We illustrate this with two examples defined in

two spacetime dimensions. The first one is the self-interacting Thirring model.

The second one is a model of Dirac fermions coupled to a dynamic scalar field

that gives rise to the Gross-Neveu model. The proposed cold atom experiments

can be used to probe spectral or correlation properties of interacting quantum

field theories thereby presenting an alternative to lattice gauge theory

simulations.

\\ ( http://arxiv.org/abs/1006.2975 , 241kb)

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arXiv:1006.2999

Date: Tue, 15 Jun 2010 14:21:54 GMT (86kb)

Title: Dynamical Density Fluctuation of Superfluids near Critical Velocities

Authors: Yusuke Kato and Shohei Watabe

Categories: cond-mat.quant-gas cond-mat.stat-mech

Comments: 4 pages, 1figure

\\

We propose a stability criterion of superfluids in condensed Bose-Einstein

systems, which incorporates the spectral function or the autocorrelation

function of the local density. Within the Gross-Pitaevskii-Bogoliubov theory,

we demonstrate the validity of our criterion for the soliton-emission

instability, with use of explicit forms of zero modes of the Bogoliubov

equation and a dynamical scaling near the saddle-node bifurcation. We also show

that the criterion is applicable to the Landau phonon instability and the

Landau roton instability within the single-mode approximation.

\\ ( http://arxiv.org/abs/1006.2999 , 86kb)

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arXiv:1006.3004

Date: Tue, 15 Jun 2010 14:42:52 GMT (267kb)

Title: The approach to vortex reconnection

Authors: Richard Tebbs, Anthony J. Youd, and Carlo F. Barenghi

Categories: cond-mat.quant-gas

Comments: 11 pages, 9 figures

\\

We present numerical solutions of the Gross--Pitaevskii equation

corresponding to reconnecting vortex lines. We determine the separation of

vortices as a function of time during the approach to reconnection, and study

the formation of pyramidal vortex structures. Results are compared with

analytical work and numerical studies based on the vortex filament method.

\\ ( http://arxiv.org/abs/1006.3004 , 267kb)

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arXiv:1006.3006

Date: Tue, 15 Jun 2010 15:05:25 GMT (38kb)

Title: Ultracold RbSr molecules can be formed by magnetoassociation

Authors: Piotr S. Zuchowski, J. Aldegunde and Jeremy M. Hutson

Categories: physics.atom-ph

Comments: 5 pages, 2 figures

\\

We investigate the interactions between ultracold alkali metal atoms and

closed-shell atoms using electronic structure calculations on the prototype

system Rb+Sr. There are molecular bound states that can be tuned across atomic

thresholds with magnetic field, and there are previously neglected terms in the

collision Hamiltonian that can produce zero-energy Feshbach resonances with

significant widths. The largest effect comes from the interaction-induced

variation of the Rb hyperfine coupling. The resonances may be used to form

paramagnetic polar molecules if the magnetic field can be controlled precisely

enough.

\\ ( http://arxiv.org/abs/1006.3006 , 38kb)

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arXiv:1006.3024

Date: Tue, 15 Jun 2010 16:27:07 GMT (200kb)

Title: Josephson tunneling of dark solitons in a double-well potential

Authors: H. Susanto, J. Cuevas, P. Kruger

Categories: cond-mat.quant-gas nlin.PS

Comments: 4 pages, submitted

\\

The dynamics of a quasi one-dimensional Bose-Einstein condensate in a double

well potential, modelled by an effectively one-dimensional nonlinear

Schrodinger equation, is studied. When a dark soliton is loaded into one of the

wells, it is shown that the soliton can tunnel between them experiencing the

physics known for electrons in a Josephson junction, or be self-trapped. A

coupled-mode approximation is derived to explain the observations. As dark

solitons are non-ground state excitations, numerical stability analysis based

on the full equation is necessary, where it is shown that such tunneling when

occurs can be stable. Through path following methods, unstable tunnelings are

also obtained. Finally, we outline an experimental scheme designed to explore

such dark soliton dynamics in the laboratory.

\\ ( http://arxiv.org/abs/1006.3024 , 200kb)

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arXiv:1006.3038

Date: Tue, 15 Jun 2010 17:30:53 GMT (158kb)

Title: Creation of NOON states by double Fock-state/Bose-Einstein condensates

Authors: W. J. Mullin \and F. Lalo\"{e}

Categories: quant-ph

Comments: 8 pages 5 figures

\\

NOON states (states of the form $|N>_{a}|0>_{b}+|0>_{a}|N>_{b}$ where $a$ and

$b$ are single particle states) have been used for predicting violations of

hidden-variable theories (Greenberger-Horne-Zeilinger violations) and are

valuable in metrology for precision measurements of phase at the Heisenberg

limit. We show theoretically how the use of two Fock state/Bose-Einstein

condensates as sources in a modified Mach Zender interferometer can lead to the

creation of the NOON state in which $a$ and $b$ refer to arms of the

interferometer and $N$ is the total number of particles in the two condensates.

The modification of the interferometer involves making conditional ``side''

measurements of a few particles near the sources. These measurements put the

remaining particles in a superposition of two phase states, which are converted

into NOON states by a beam splitter. The result is equivalent to the quantum

experiment in which a large molecule passes through two slits. The NOON states

are combined in a final beam splitter and show interference. Attempts to detect

through which ``slit'' the condensates passed destroys the interference.

\\ ( http://arxiv.org/abs/1006.3038 , 158kb)

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arXiv:1006.3063

Date: Tue, 15 Jun 2010 19:49:25 GMT (258kb)

Title: Non-classical Rotational Inertia in a Two-dimensional Bosonic Solid

Containing Grain Boundaries

Authors: Chandan Dasgupta and Oriol T. Valls

Categories: cond-mat.quant-gas

Comments: Ten pages, including figures

\\

We study the occurrence of non-classical rotational inertia (NCRI) arising

from superfluidity along grain boundaries in a two-dimensional bosonic system.

We make use of a standard mapping between the zero-temperature properties of

this system and the statistical mechanics of interacting vortex lines in the

mixed phase of a type-II superconductor. In the mapping, the liquid phase of

the vortex system corresponds to the superfluid bosonic phase. We consider

numerically obtained polycrystalline configurations of the vortex lines in

which the microcrystals are separated by liquid-like grain boundary regions

which widen as the vortex system temperature increases. The NCRI of the

corresponding zero-temperature bosonic systems can then be numerically

evaluated by solving the equations of superfluid hydrodynamics in the channels

near the grain boundaries. We find that the NCRI increases very abruptly as the

liquid regions in the vortex system (equivalently, superfluid regions in the

bosonic system) form a connected, system-spannig structure with one or more

closed loops. The implications of these results for experimentally observed

supersolid phenomena are discussed.

\\ ( http://arxiv.org/abs/1006.3063 , 258kb)

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arXiv:1006.3067

Date: Tue, 15 Jun 2010 19:57:16 GMT (76kb)

Title: Exact dynamics of two cold bosons in a harmonic trap

Authors: Tomasz Sowinski, Miroslaw Brewczyk, Mariusz Gajda, Kazimierz Rzazewski

Categories: quant-ph cond-mat.quant-gas

Comments: 9 figures

\\

We study dynamics of two interacting ultra cold Bose atoms in a harmonic

oscillator potential in one spatial dimension. Making use of the exact solution

of the eigenvalue problem of a particle in the delta-like potential we study a

time evolution of some particularly chosen initial states, all being a two-fold

product of identical states of both particles. The corresponding time dependent

single particle density matrix is obtained and diagonalized and single particle

orbitals are found. The evolution of the orbital corresponding to the largest

eigenvalue is then compared to the evolution given by the Gross-Pitaevskii

equation. We show that if initially the center of mass and relative degrees of

freedom are entangled then the Gross-Pitaevskii equation fails to reproduce the

exact dynamics. We stress that predictions of our study can be verified

experimentally in an optical lattice in the low-tunneling limit when two atoms

occupy each lattice site.

\\ ( http://arxiv.org/abs/1006.3067 , 76kb)

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arXiv:1006.3183

Date: Wed, 16 Jun 2010 11:18:09 GMT (161kb)

Title: Turbulent superfluid profiles in a counterflow channel

Authors: L. Galantucci, C.F. Barenghi, M. Sciacca, M. Quadrio, and P. Luchini

Categories: cond-mat.other

Comments: 3 double figures, 9 pages

\\

We have developed a two-dimensional model of quantised vortices in helium II

moving under the influence of applied normal fluid and superfluid in a

counterflow channel. We predict superfluid and vortex-line density profiles

which could be experimentally tested using recently developed visualization

techniques.

\\ ( http://arxiv.org/abs/1006.3183 , 161kb)

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arXiv:1006.3206

Date: Wed, 16 Jun 2010 13:24:46 GMT (155kb)

Title: Effective merging dynamics of two and three fluid vortices: Application

to two-dimensional decaying turbulence

Authors: Cl\'ement Sire, Pierre-Henri Chavanis, and Julien Sopik

Categories: cond-mat.stat-mech physics.flu-dyn

Comments: 4 pages; 3 figures

\\

We present a kinetic theory of two-dimensional decaying turbulence in the

context of two-body and three-body vortex merging processes. By introducing the

equations of motion for two or three vortices in the effective noise due to all

the other vortices, we demonstrate analytically that a two-body mechanism

becomes inefficient at low vortex density $n\ll 1$. When the more efficient

three-body vortex mergings are considered, we show that $n\sim t^{-\xi}$, with

$\xi=1$. We generalize this argument to three-dimensional geostrophic

turbulence, finding $\xi=5/4$, in excellent agreement with direct Navier-Stokes

simulations [J.\,C. McWilliams \emph{et al.}, J. Fluid Mech. {\bf 401}, 1

(1999)].

\\ ( http://arxiv.org/abs/1006.3206 , 155kb)

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\\

arXiv:1006.3212

Date: Wed, 16 Jun 2010 13:44:15 GMT (254kb,D)

Title: Interactions Between Rydberg-Dressed Atoms

Authors: J. E. Johnson and S. L. Rolston

Categories: physics.atom-ph quant-ph

Comments: 5 pages, 7 figures

\\

We examine interactions between atoms continuously and coherently driven

between the ground state and a Rydberg state, producing "Rydberg-dressed

atoms." Because of the large dipolar coupling between two Rydberg atoms, a

small admixture of Rydberg character into a ground state can produce an atom

with a dipole moment of a few Debye, the appropriate size to observe

interesting dipolar physics effects in cold atom systems. We have calculated

the interaction energies for atoms that interact via the dipole-dipole

interaction and find that due to blockade effects, the R-dependent two-atom

interaction terms are limited in size, and can be R-independent up until the

dipolar energy is equal to the detuning. This produces R-dependent interactions

different from the expected 1/R^3 dipolar form, which have no direct analogy in

condensed matter physics, and could lead to new quantum phases in trapped

Rydberg systems.

\\ ( http://arxiv.org/abs/1006.3212 , 254kb)

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\\

arXiv:1006.3240

Date: Wed, 16 Jun 2010 14:48:36 GMT (124kb)

Title: Hysteresis effects in Bose-Einstein condensates

Authors: Andrea Sacchetti

Categories: quant-ph cond-mat.quant-gas

Comments: 10 pages, 2 figures

\\

Here, we consider damped two-components Bose-Einstein condensates with

many-body interactions. We show that, when the external trapping potential has

a double-well shape and when the nonlinear coupling factors are modulated in

time, hysteresis effects may appear under some circumstances. Such hysteresis

phenomena are a result of the joint contribution between the appearance of

saddle node bifurcations and damping effect.

\\ ( http://arxiv.org/abs/1006.3240 , 124kb)

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\\

arXiv:1006.3258

Date: Wed, 16 Jun 2010 16:08:36 GMT (336kb)

Title: Ultracold atoms in a cavity mediated double-well system

Authors: Jonas Larson and Jani-Petri Martikainen

Categories: quant-ph cond-mat.quant-gas

Comments: 11 pages, 10 figures

\\

We study ground state properties and dynamics of a dilute ultracold atomic

gas in a double well potential. The Gaussian barrier separating the two wells

derives from the interaction between the atoms and a quantized field of a

driven Fabry-Perot cavity. Due to intrinsic atom-field nonlinearity, several

novel phenomena arise being the focus of this work. For the ground state, there

is a critical pumping amplitude in which the atoms self-organize and the intra

cavity field amplitude drastically increases. In the dynamical analysis, we

show that the Josephson oscillations depend strongly on the atomic density and

may be greatly suppressed within certain regimes, reminiscent of self-trapping

of Bose-Einstein condensates in double-well setups. This pseudo self-trapping

effect is studied within a mean-field treatment valid for large atom numbers.

For small numbers of atoms, we consider the analogous many-body problem and

demonstrate a collapse-revival structure in the Josephson oscillations.

\\ ( http://arxiv.org/abs/1006.3258 , 336kb)

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\\

arXiv:1006.3330

Date: Wed, 16 Jun 2010 21:28:41 GMT (161kb)

Title: Non-thermal equilibration of a one-dimensional Fermi gas

Authors: Matthias Kronenwett and Thomas Gasenzer

Categories: cond-mat.quant-gas cond-mat.stat-mech hep-ph

Comments: 4 pages, 4 figures

\\

Equilibration of an isolated Fermi gas in one spatial dimension after an

interaction quench is studied. Evaluating Kadanoff-Beym dynamic equations for

correlation functions obtained from the two-particle-irreducible effective

action in nonperturbative approximation, the gas is seen to evolve to states

characterized by thermal as well as nonthermal momentum distributions,

depending on the assumed initial conditions. For total energies near the Fermi

temperature, stationary power laws emerge for the high-momentum tails while at

lower momenta the distributions are of Fermi-Dirac type. The relation found

between fluctuations and dissipation exhibits nonthermal final states.

\\ ( http://arxiv.org/abs/1006.3330 , 161kb)

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\\

arXiv:1006.3406

Date: Thu, 17 Jun 2010 08:46:18 GMT (40kb)

Title: Pseudogap Phase and Remnant Fermi Surface in Ultracold Fermi Gases

Authors: A. Perali, P. Pieri, F. Palestini, G. C. Strinati, J. T. Stewart, J.

P. Gaebler, T. E. Drake, D. S. Jin

Categories: cond-mat.quant-gas

Comments: 6 pages, 6 figures

\\

Wave-vector resolved radio frequency (rf) spectroscopy data for an ultracold

trapped Fermi gas are reported for several couplings at Tc, and extensively

analyzed in terms of a pairing-fluctuation theory. This combined analysis shows

that the strongly non-Fermi-liquid behavior associated with the presence of a

pseudogap coexists with a robust remnant Fermi surface over a wide coupling

range, which in turn sets the boundary of the pseudogap phase.

\\ ( http://arxiv.org/abs/1006.3406 , 40kb)

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\\

arXiv:1006.3461

Date: Thu, 17 Jun 2010 13:29:57 GMT (22kb,D)

Title: On the bosonic behavior of mean-field fluctuations in atomic ensembles

Authors: Michael Keyl and Dirk-Michael Schlingemann and Zoltan Zimboras

Categories: quant-ph

Comments: 19 pages

\\

The mean field fluctuations of large atomic ensembles can behave like bosonic

modes, i.e. they induce a state on an appropriate system of bosonic modes. The

most prominent example is that, if the atomic ensemble is in a homogenous

product state, then the mean-field fluctuations are inducing a Gaussian state

on a system of bosonic modes. In the present paper we show that for atomic

ensemble states with exponentially decaying correlations (e.g. with respect to

the distance of atoms) the mean-field fluctuations are inducing (possibly

non-Gaussian) states on the on a system of bosonic modes. This result is true

for a general lattice of atomic systems that is equipped with a reasonable

distance function.

\\ ( http://arxiv.org/abs/1006.3461 , 22kb)

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\\

arXiv:1006.3466 (*cross-listing*)

Date: Thu, 17 Jun 2010 13:44:30 GMT (67kb)

Title: Collective atomic recoil motion in short-pulse multi-matter-optical wave

mixing

Authors: L. Deng and E.W. Hagley

Categories: cond-mat.quant-gas quant-ph

Comments: This manuscript was submitted for publication in Nov., 2009

\\

An analytical perturbation theory of short-pulse, matter-wave superradiant

scatterings is presented. We show that Bragg resonant enhancement is

incapacitated and both positive and negative order scatterings contribute

equally. We further show that propagation gain is small and scattering events

primarily occur at the end of the condensate where the generated field has

maximum strength, thereby explaining the apparent ``asymmetry" in the scattered

components with respect to the condensate center. In addition, the generated

field travels near the speed of light in a vacuum, resulting in significant

spontaneous emission when the one-photon detuning is not sufficiently large.

Finally, we show that when the excitation rate increases, the generated-field

front-edge-steepening and peak forward-shifting effects are due to depletion of

the ground state matter wave.

\\ ( http://arxiv.org/abs/1006.3466 , 67kb)

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\\

arXiv:1006.3539

Date: Thu, 17 Jun 2010 18:26:13 GMT (743kb)

Title: Femtosecond Quasiparticle and Phonon Dynamics in Superconducting

YBa2Cu3O7 Studied by Wideband Terahertz Spectroscopy

Authors: A. Pashkin, M. Porer, M. Beyer, K. W. Kim, A. Dubroka, C. Bernhard, X.

Yao, Y. Dagan, R. Hackl, A. Erb, J. Demsar, R. Huber, and A. Leitenstorfer

Categories: cond-mat.supr-con

Comments: 4 pages, 4 figures

\\

We measure the anisotropic mid-infrared response of electrons and phonons in

bulk YBa2Cu3O7 after femtosecond photoexcitation. A line shape analysis of

specific lattice modes reveals their transient occupation and coupling to the

superconducting condensate. The apex oxygen vibration is strongly excited

within 150\,fs demonstrating that the lattice absorbs a major portion of the

pump energy before the quasiparticles are thermalized. Our results attest to

substantial electron-phonon scattering and introduce a powerful concept probing

electron-lattice interactions in a variety of complex materials.

\\ ( http://arxiv.org/abs/1006.3539 , 743kb)

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\\

arXiv:1006.3550

Date: Thu, 17 Jun 2010 19:17:11 GMT (1500kb,D)

Title: Dynamics of a tunable superfluid junction

Authors: L. J. LeBlanc, A. B. Bardon, J. McKeever, M. H. T. Extavour, D.

Jervis, J. H. Thywissen, F. Piazza and A. Smerzi

Categories: cond-mat.quant-gas

Comments: 7 pages, 6 figures

\\

We study the population dynamics of a Bose-Einstein condensate in a

double-well potential with tunable barrier height. In the regime of weak

inter-well coupling, we observe Josephson plasma oscillations as expected.

However, in the strong-coupling regime, a second frequency enters the dynamics.

We explain the amplitude, frequency, and nature of these two modes by with

Gross-Pitaevskii calculations throughout the weak- to strong-coupling

crossover. Our results interpolate between two standard paradigms of

superfluidity: hydrodynamics and Josephson dynamics.

\\ ( http://arxiv.org/abs/1006.3550 , 1500kb)

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The replacements:

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\\

arXiv:1006.1438

replaced with revised version Fri, 11 Jun 2010 03:51:54 GMT (90kb,D)

Title: Semiclassical dynamics of quasi-one-dimensional, attractive

Bose-Einstein condensates

Authors: Alexander Tovbis and Mark A. Hoefer

Categories: cond-mat.quant-gas

Comments: 8 pages, 2 figures

\\ ( http://arxiv.org/abs/1006.1438 , 90kb)

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\\

arXiv:1001.2592

replaced with revised version Fri, 11 Jun 2010 09:52:04 GMT (34kb)

Title: The Universality and stability for a dilute Bose gas with a Feshbach

resonance

Authors: Yu-Li Lee and Yu-Wen Lee

Categories: cond-mat.quant-gas cond-mat.other

Comments: 6 pages, 4 figures

Journal-ref: Phys. Rev. A 81, 063613 (2010)

\\ ( http://arxiv.org/abs/1001.2592 , 34kb)

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\\

arXiv:0904.4667

replaced with revised version Mon, 14 Jun 2010 10:02:04 GMT (1464kb,D)

Title: Fermionic Projected Entangled Pair States

Authors: Christina V. Kraus, Norbert Schuch, Frank Verstraete, J. Ignacio Cirac

Categories: quant-ph cond-mat.other

Comments: 7 pages, 3 figures

Journal-ref: Phys. Rev. A 81, 052338 (2010)

DOI: 10.1103/PhysRevA.81.052338

\\ ( http://arxiv.org/abs/0904.4667 , 1464kb)

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\\

arXiv:0912.4205

replaced with revised version Tue, 15 Jun 2010 09:03:40 GMT (2075kb)

Title: Population and mass imbalance in atomic Fermi gases

Authors: J.E. Baarsma, K.B. Gubbels, H.T.C. Stoof

Categories: cond-mat.quant-gas

Comments: 17 pages, 17 figures

\\ ( http://arxiv.org/abs/0912.4205 , 2075kb)

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\\

arXiv:0909.1192

replaced with revised version Tue, 15 Jun 2010 11:35:38 GMT (69kb,D)

Title: Ground-state properties of few dipolar bosons in a quasi-one-dimensional

harmonic trap

Authors: Frank Deuretzbacher, Jonas C. Cremon, Stephanie M. Reimann

Categories: cond-mat.quant-gas cond-mat.other

Journal-ref: Phys. Rev. A 81, 063616 (2010)

DOI: 10.1103/PhysRevA.81.063616

\\ ( http://arxiv.org/abs/0909.1192 , 69kb)

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\\

arXiv:1003.5667

replaced with revised version Wed, 16 Jun 2010 10:43:15 GMT (94kb,D)

Title: Decay of polarons and molecules in a strongly polarized Fermi gas

Authors: G. M. Bruun, P. Massignan

Categories: cond-mat.quant-gas

Comments: Version accepted in PRL. Added discussion of three-body losses to

deeply bound molecular states

\\ ( http://arxiv.org/abs/1003.5667 , 94kb)

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\\

arXiv:1006.3179

replaced with revised version Thu, 17 Jun 2010 01:35:12 GMT (1147kb,D)

Title: Topological quantum phase transitions of attractive spinless fermions in

a honeycomb lattice

Authors: Dario Poletti, Christian Miniatura and Benoit Gremaud

Categories: cond-mat.quant-gas

Comments: 4 pages, 3 figures

\\ ( http://arxiv.org/abs/1006.3179 , 1147kb)

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\\

arXiv:0908.2159

replaced with revised version Thu, 17 Jun 2010 03:45:28 GMT (42kb)

Title: Universal four-component Fermi gas in one dimension

Authors: Yusuke Nishida and Dam T. Son

Categories: cond-mat.quant-gas nucl-th

Comments: 6 pages, 2 figures; (v2) Efimov effect for 5 bosons in 1D is

discussed

Report-no: MIT-CTP 4055, INT-PUB-09-038

\\ ( http://arxiv.org/abs/0908.2159 , 42kb)

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\\

arXiv:1006.3250 (*cross-listing*)

replaced with revised version Thu, 17 Jun 2010 14:44:39 GMT (836kb)

Title: Observation of collective atomic recoil motion in a momentum-squeezed,

ultra-cold, degenerate fermion gas

Authors: Pengjun Wang, L. Deng, E.W. Hagley, Zhengkun Fu, and Shijie Chai, Jing

Zhang

Categories: cond-mat.quant-gas quant-ph

\\ ( http://arxiv.org/abs/1006.3250 , 836kb)

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Till next time,

Matt.

-- ========================================================================= Dr M. J. Davis, Associate Professor in Physics School of Mathematics and Physics, ph : +61 7 334 69824 The University of Queensland, fax : +61 7 336 51242 Brisbane, QLD 4072, mdavis_at_physics.uq.edu.au Australia. 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 ========================================================================= _______________________________________________ Matts-arxiv mailing list Matts-arxiv_at_lists.sps.uq.edu.auReceived on Wed Sep 01 2010 - 11:01:36 EST

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