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

Date: Tue, 19 May 2009 08:44:04 +1000

Date: Tue, 19 May 2009 08:44:04 +1000

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

Thanks for this week's abstracts goes to Geoff Lee. There are 13 new preprints

and 7 replacements:

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arXiv:0902.3649

Date: Fri, 20 Feb 2009 19:45:00 GMT (149kb)

Title: Stimulated Raman scattering in an optical parametric oscillator based on

periodically poled MgO-doped stoichiometric LiTaO3

Authors: T-H. My (LAC), O. Robin (LAC), O. Mhibik (LAC), C. Drag (LAC), and F.

Bretenaker (LAC)

Categories: physics.optics physics.ins-det

Comments: 6 figures

\\

The evolution versus pump power of the spectrum of a singly resonant optical

parametric oscillator based on an MgO-doped periodically poled stoichiometric

lithium tantalate crystal is observed. The onset of cascade Raman lasing due to

stimulated Raman scattering in the nonlinear crystal is analyzed. Spurious

frequency doubling and sum-frequency generation phenomena are observed and

understood. A strong reduction of the intracavity Raman scattering is obtained

by a careful adjustment of the cavity losses.

\\ ( http://arxiv.org/abs/0902.3649 , 149kb)

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arXiv:0902.3685

Date: Fri, 20 Feb 2009 23:25:06 GMT (91kb)

Title: The Mass of a Spin Vortex in a Bose-Einstein Condensate

Authors: Ari M. Turner

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

Comments: 5 pages, 3 figures

\\

In contrast to charge vortices in a superfluid, spin vortices in a

ferromagnetic condensate move inertially (if the condensate has zero

magnetization along an axis). The mass of spin vortices depends on the

spin-dependent interactions, and can be measured as a part of experiments on

how spin vortices orbit one another. For Rb87 in a 1 micron thick trap m_v is

about 10^-21 kg.

\\ ( http://arxiv.org/abs/0902.3685 , 91kb)

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arXiv:0902.3720

Date: Sat, 21 Feb 2009 05:49:35 GMT (241kb)

Title: Diffusion of Inhomogeneous Vortex Tangle and Decay of Superfluid

Turbulence

Authors: Sergey K. Nemirovskii

Categories: cond-mat.other

Comments: 7 pages, 6 figures

\\

The theory describing the evolution of inhomogeneous vortex tangle at zero

temperature is developed on the bases of kinetics of merging and splitting

vortex loops. Vortex loops composing the vortex tangle can move as a whole with

some drift velocity depending on their structure and their length. The flux of

length, energy, momentum etc. executed by the moving vortex loops takes a

place. Situation here is exactly the same as in usual classical kinetic theory

with the difference that the "carriers" of various physical quantities are not

the point particles, but extended objects (vortex loops), which possess an

infinite number of degrees of freedom with very involved dynamics. We offer to

fulfill investigation basing on supposition that vortex loops have a Brownian

structure with the only degree of freedom, namely, lengths of loops $l$. This

conception allows us to study dynamics of the vortex tangle on the basis of the

kinetic equation for the distribution function $n(l,t)$ of the density of a

loop in the space of their lengths. Imposing the coordinate dependence on the

distribution function $n(l,\mathbf{% r},t)$ and modifying the "kinetic"

equation with regard to inhomogeneous situation, we are able to investigate

various problem on the transport processes in superfluid turbulence. In this

paper we derive relation for the flux of the vortex line density

$\mathcal{L}(x,t)$. The correspoding evolution of quantity $\mathcal{L}(x,t)$

obeys the diffusion type equation as it can be expected from dimensional

analysis. The according diffusion coefficient is evaluated from calculation of

the (size dependent) free path of the vortex loops. We use this equation to

describe the decay of the vortex tangle at very low temperature. We compare

that solution with recent experiments on decay of the superfluid turbulence.

\\ ( http://arxiv.org/abs/0902.3720 , 241kb)

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arXiv:0902.3848

Date: Mon, 23 Feb 2009 04:59:30 GMT (31kb)

Title: Reduced fidelity in topological quantum phase transitions

Authors: Erik Eriksson and Henrik Johannesson

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

Comments: 4 pages, 2 figures

\\

We study the reduced fidelity between local states of lattice systems

exhibiting topological order. By exploiting mappings to spin models with

classical order, we are able to analytically extract the scaling behavior of

the reduced fidelity at the corresponding quantum phase transitions out of the

topologically ordered phases. Our results suggest that the reduced fidelity,

albeit being a local measure, generically serves as a faithful marker of a

topological quantum phase transition.

\\ ( http://arxiv.org/abs/0902.3848 , 31kb)

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arXiv:0902.3967

Date: Mon, 23 Feb 2009 17:48:47 GMT (32kb)

Title: Josephson oscillations between exciton condensates in electrostatic

traps

Authors: Massimo Rontani, L. J. Sham

Categories: cond-mat.mes-hall

Comments: RevTeX 4.0. 4 pages, 2 figures

\\

Technological advances allow for tunable lateral confinement of cold dipolar

excitons in coupled quantum wells. We consider theoretically the Josephson

effect between exciton condensates in two traps separated by a weak link. The

flow of the exciton supercurrent is driven by the dipole energy difference

between the traps. The Josephson oscillations may be observed after ensemble

average of the time correlation of photons separately emitted from the two

traps. The fringe visibility is controlled by the trap coupling and is robust

against quantum and thermal fluctuations.

\\ ( http://arxiv.org/abs/0902.3967 , 32kb)

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arXiv:0902.3969

Date: Mon, 23 Feb 2009 17:59:32 GMT (160kb)

Title: Faraday patterns in dipolar Bose-Einstein condensates

Authors: R. Nath and L. Santos

Categories: cond-mat.other

Comments: 4 pages, 10 figures

\\

Faraday patterns can be induced in Bose-Einstein condensates by a periodic

modulation of the system nonlinearity. We show that these patterns are

remarkably different in dipolar gases with a roton-maxon excitation spectrum.

Whereas for non-dipolar gases the pattern size decreases monotonously with the

driving frequency, patterns in dipolar gases present, even for shallow roton

minima, a highly non trivial frequency dependence characterized by abrupt

pattern size transitions, which are especially pronounced when the dipolar

interaction is modulated. Faraday patterns constitute hence an optimal tool for

revealing the onset of the roton minimum, a major key feature of dipolar gases.

\\ ( http://arxiv.org/abs/0902.3969 , 160kb)

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arXiv:0902.3980

Date: Mon, 23 Feb 2009 19:58:19 GMT (42kb,D)

Title: Causality in Condensates: Grey Solitons as Remnants of BEC Formation

Authors: Wojciech H. Zurek

Categories: cond-mat.stat-mech

Comments: Phys. Rev. Lett., in press

\\

Symmetry breaking during phase transitions can lead to the formation of

topological defects (such as vortex lines in superfluids). However, the usually

studied BEC's have the shape of a cigar, a geometry that impedes vortex

formation, survival, and detection. I show that, in elongated traps, one can

expect the formation of "grey solitons" (long-lived, non-topological "phase

defects") as a result of the same mechanism. Their number will rise

approximately in proportion to the transition rate. This steep rise is due to

the increasing size of the region of the BEC cigar where the phase of the

condensate wavefunction is chosen locally (rather than passed on from the

already formed BEC).

\\ ( http://arxiv.org/abs/0902.3980 , 42kb)

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arXiv:0902.4119

Date: Tue, 24 Feb 2009 11:17:08 GMT (34kb)

Title: Multiple condensed phases in attractively interacting Bose systems

Authors: M. M\"annel, K. Morawetz, P. Lipavsk\'y

Categories: cond-mat.stat-mech

\\

We investigate a Bose gas with finite-range interaction using a scheme to

eliminate unphysical repeated collisions in the T-matrix approximation. In this

way the corrected T-matrix becomes suitable to calculate properties below the

critical temperature. For attractive interaction, the Evans-Rashid transition

occurs from the quasi-ideal Bose gas to the BCS-like phase with a gaped

dispersion. The gap decreases with increasing density and vanishes at a

critical density where the single-particle dispersion becomes linear for small

momenta indicating Bose-Einstein condensation.

\\ ( http://arxiv.org/abs/0902.4119 , 34kb)

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arXiv:0902.4134

Date: Tue, 24 Feb 2009 12:26:57 GMT (444kb)

Title: A new view on superfluidity

Authors: V. A. Golovko

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

Comments: Full version of a paper published earlier in Physica A, 45 pages, 2

figures

\\

This paper represents the full version of a paper published earlier in

Physica A [246 (1997), 275]. The present paper includes argumentation, proofs

and details omitted in the shortened version. The papers are a further

development of the approach in quantum statistical mechanics proposed by the

author. The hierarchy of equations for reduced density matrices obtained

previously is extended to the case corresponding to the Bose-Einstein

condensation. The relevant state of the system with a condensate can be

superfluid as well as nonsuperfluid. Special attention is given to the

thermodynamics of superfluid systems. According to the results of the papers

superfluidity is the state of a fluid whose symmetry is spontaneously broken

because of a stationary flow. The state corresponds to thermodynamic

equilibrium while the magnitude of the flow depends upon the temperature and is

determined by thermodynamic considerations. The equations obtained are solved

in two simple cases. The physical origin of superfluidity, peculiarities of the

phenomenon in closed volumes and the critical velocity are discussed as well.

\\ ( http://arxiv.org/abs/0902.4134 , 444kb)

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arXiv:0902.4205

Date: Tue, 24 Feb 2009 17:56:11 GMT (2007kb)

Title: Small Numbers of Vortices in Anisotropic Traps

Authors: S. McEndoo and Th. Busch

Categories: cond-mat.other

Comments: 7 pages, 7 figures

\\

We investigate the appearance of vortices and vortex lattices in

two-dimensional, anisotropic and rotating Bose-Einstein condensates. Once the

anisotropy reaches a critical value, the positions of the vortex cores in the

ground state are no longer given by an Abrikosov lattice geometry, but by a

linear arrangement. Using a variational approach, we determine the critical

stirring frequency for a single vortex as well as the equilibrium positions of

a small number of vortices.

\\ ( http://arxiv.org/abs/0902.4205 , 2007kb)

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arXiv:0902.4653

Date: Thu, 26 Feb 2009 20:51:55 GMT (402kb)

Title: FFLO vs Bose-Fermi mixture in polarized 1D Fermi gas on a Feshbach

resonance: a 3-body study

Authors: Stefan K. Baur, John Shumway, Erich J. Mueller

Categories: cond-mat.supr-con

Comments: 4 pages, 3 figures

\\

We study the three-fermion problem within a 1D model of a Feshbach resonance

in order to gain insight into how the FFLO-like state at small negative

scattering lengths evolves into a Bose-Fermi mixture at small positive

scattering lengths. The FFLO state possesses an oscillating superfluid

correlation function, while in a Bose-Fermi mixture correlations are monotonic.

We find that this behavior is is already present at the 3-body level. We

present an exact study of the 3-body problem, and compare the results to

scalable quantum Monte Carlo calculations.

\\ ( http://arxiv.org/abs/0902.4653 , 402kb)

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arXiv:0902.4655

Date: Thu, 26 Feb 2009 18:10:24 GMT (1493kb)

Title: Binding between two-component bosons in one dimension

Authors: Emmerich Tempfli, Sascha Z\"ollner, Peter Schmelcher

Categories: cond-mat.other

Comments: 9 pages, 10 figures

\\

We investigate the ground state of one-dimensional few-atom Bose-Bose

mixtures under harmonic confinement throughout the crossover from weak to

strong inter-species attraction. The calculations are based on the numerically

exact multi-configurational time-dependent Hartree method. For repulsive

components we detail the condition for the formation of a molecular

Tonks-Girardeau gas in the regime of intermediate inter-species interactions,

and the formation of a molecular condensate for stronger coupling. Beyond a

critical inter-species attraction, the system collapses to an overall bound

state. Different pathways emerge for different particle numbers and

intra-species interactions. In particular, for mixtures with one attractive

component, this species can be viewed as an effective potential dimple in the

trap center for the other, repulsive component.

\\ ( http://arxiv.org/abs/0902.4655 , 1493kb)

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arXiv:0902.4523

Date: Thu, 26 Feb 2009 07:27:50 GMT (276kb)

Title: Universal scaling in a strongly interacting Rydberg gas

Authors: Robert L\"ow, Hendrik Weimer, Ulrich Raitzsch, Rolf Heidemann, Vera

Bendkowsky, Bj\"orn Butscher, Hans Peter B\"uchler, and Tilman Pfau

Categories: quant-ph

Comments: 5 pages, 3 figures

\\

We study a gas of ultracold atoms resonantly driven into a strongly

interacting Rydberg state. The long distance behavior of the spatially frozen

effective pseudospin system is determined by a set of dimensionless parameters,

and we find that the experimental data exhibits algebraic scaling laws for the

excitation dynamics and the saturation of Rydberg excitation. Mean field

calculations as well as numerical simulations provide an excellent agreement

with the experimental finding, and are evidence for universality in a strongly

interacting frozen Rydberg gas.

\\ ( http://arxiv.org/abs/0902.4523 , 276kb)

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The replacements:

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arXiv:0812.4422

replaced with revised version Fri, 20 Feb 2009 16:50:40 GMT (198kb,D)

Title: Quantum Simulation of the Hubbard Model: The Attractive Route

Authors: A. F. Ho, M. A. Cazalilla, T. Giamarchi

Categories: cond-mat.str-el

Comments: 11 pages, 5 figs. New version as accepted in PRA. We have clarified

the models we are discussing in various places, and expanded on the critical

number estimate to include both K40 and Li6 in section V. Also added

references

\\ ( http://arxiv.org/abs/0812.4422 , 198kb)

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arXiv:0901.1300

replaced with revised version Thu, 19 Feb 2009 10:06:12 GMT (903kb)

Title: Coherent collapse of a dipolar Bose-Einstein condensate for different

trap geometries

Authors: J Metz, T Lahaye, B Fr\"ohlich, A Griesmaier, T Pfau, H Saito, Y

Kawaguchi, and M Ueda

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

\\ ( http://arxiv.org/abs/0901.1300 , 903kb)

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arXiv:0902.2558

replaced with revised version Thu, 19 Feb 2009 16:26:38 GMT (205kb,D)

Title: Probing Interactions between Ultracold Fermions

Authors: G. K. Campbell, M. M. Boyd, J. W. Thomsen, M. J. Martin, S. Blatt, M.

D. Swallows, T. L. Nicholson, T. Fortier, C. W. Oates, S. A. Diddams, N. D.

Lemke, P. Naidon, P. Julienne, Jun Ye, A. D. Ludlow

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

Comments: accepted to Science

\\ ( http://arxiv.org/abs/0902.2558 , 205kb)

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arXiv:0811.1910

replaced with revised version Sat, 21 Feb 2009 15:54:35 GMT (2738kb)

Title: Solitons with Cubic and Quintic Nonlinearities Modulated in Space and

Time

Authors: A.T. Avelar, D. Bazeia, W.B. Cardoso

Categories: quant-ph cond-mat.soft hep-th

Comments: 4 pages, 6 figures; version to appear in PRE, RC

\\ ( http://arxiv.org/abs/0811.1910 , 2738kb)

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arXiv:0812.2310

replaced with revised version Mon, 23 Feb 2009 01:19:50 GMT (711kb)

Title: Ramsey interferometry with an atom laser

Authors: D. D\"oring, J. E. Debs, N. P. Robins, C. Figl, P. A. Altin, and J. D.

Close

Categories: physics.atom-ph

Comments: submitted version, 4 pages, 3 figures

\\ ( http://arxiv.org/abs/0812.2310 , 711kb)

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arXiv:0807.3606

replaced with revised version Tue, 24 Feb 2009 06:16:46 GMT (16kb)

Title: Defect production due to quenching through a multicritical point

Authors: Uma Divakaran, Victor Mukherjee, Amit Dutta and Diptiman Sen

Categories: cond-mat.stat-mech

Comments: 4 pages, 2 figures, updated references and added one figure

Journal-ref: J. Stat. Mech. (2009) P02007

\\ ( http://arxiv.org/abs/0807.3606 , 16kb)

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arXiv:0812.4863

replaced with revised version Mon, 23 Feb 2009 22:59:35 GMT (241kb)

Title: Polarization-based Light-Atom Quantum Interface with an All-optical Trap

Authors: Marcin Kubasik, Marco Koschorreck, Mario Napolitano, Sebasti\'an R. de

Echaniz, Herbert Crepaz, J\"urgen Eschner, Eugene S. Polzik, Morgan W.

Mitchell

Categories: quant-ph

Comments: 8 pages, 4 figures

\\ ( http://arxiv.org/abs/0812.4863 , 241kb)

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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 =========================================================================Received on Tue May 19 2009 - 11:49:23 EST

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