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

Date: Mon, 8 May 2006 13:25:40 +1000 (EST)

Date: Mon, 8 May 2006 13:25:40 +1000 (EST)

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

Hi everyone,

This week I learnt that I should occasionally save the file with all the

abstracts in it, otherwise I might have to go through all those listings

twice!

Home page at:

http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/

On with the abstracts:

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Paper: cond-mat/0605048

Date: Tue, 2 May 2006 08:37:28 GMT (181kb)

Title: Deviation from one-dimensionality in stationary properties and

collisional dynamics of matter-wave solitons

Authors: Lev Khaykovich, Boris A. Malomed

Comments: 10 pages, 7 figures

Subj-class: Other

\\

By means of analytical and numerical methods, we study how the residual

three-dimensionality affects dynamics of solitons in an attractive

Bose-Einstein condensate loaded into a cigar-shaped trap. Based on an effective

1D Gross-Pitaevskii equation that includes an additional quintic self-focusing

term, generated by the tight transverse confinement, we find a family of exact

one-soliton solutions and demonstrate stability of the entire family, despite

the possibility of collapse in the 1D equation with the quintic self-focusing

nonlinearity. Simulating collisions between two solitons in the same setting,

we find a critical velocity, $V_{c}$, below which merger of identical in-phase

solitons is observed. Dependence of $V_{c} $ on the strength of the transverse

confinement and number of atoms in the solitons is predicted by means of the

perturbation theory and investigated in direct simulations. Symmetry breaking

in collisions of identical solitons with a nonzero phase difference is also

shown in simulations and qualitatively explained by means of an analytical

approximation.

\\ ( http://arXiv.org/abs/cond-mat/0605048 , 181kb)

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Paper: cond-mat/0605052

Date: Tue, 2 May 2006 10:45:37 GMT (791kb)

Title: Vortex localization in rotating clouds of bosons and fermions

Authors: S.M. Reimann, M. Koskinen, Y. Yu and M. Manninen

Comments: 12 pages, 12 figures

Subj-class: Mesoscopic Systems and Quantum Hall Effect; Strongly Correlated

Electrons

\\

Finite quantal systems at high angular momenta may exhibit vortex formation

and localization. These phenomena occur independent of the statistics of the

repulsively interacting particles, which may be of bosonic or fermionic nature.

We analyze the relation between vortex localization and formation of stable

Wigner molecules at high angular momenta in the view of particle-hole

duality.Trial wave functions for the vortex states and the corresponding

fermion-boson relations are discussed.

\\ ( http://arXiv.org/abs/cond-mat/0605052 , 791kb)

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Paper: cond-mat/0605056

Date: Tue, 2 May 2006 13:05:43 GMT (758kb)

Title: Dressed molecules in an optical lattice

Authors: K. B. Gubbels, D. B. M. Dickerscheid, and H. T. C. Stoof

Comments: 20 pages, 4 figures

Subj-class: Statistical Mechanics

\\

We present the theory of an atomic gas in an optical lattice near a Feshbach

resonance. We derive from first principles a generalized Hubbard model, that

incorporates all the relevant two-body physics exactly, except for the

background atom-atom scattering. For most atoms the background interactions are

negligible, but this is not true for lithium-6, which has an exceptionally

large background scattering length near the experimentally relevant Feshbach

resonance at 834 G. Therefore, we show how to include background atom-atom

scattering by solving the on-site two-body Feshbach problem exactly. We apply

the obtained solution to lithium-6 and find that the background interactions

indeed have a significant effect in this case.

\\ ( http://arXiv.org/abs/cond-mat/0605056 , 758kb)

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Paper (*cross-listing*): math-ph/0605002

Date: Mon, 1 May 2006 05:14:22 GMT (24kb)

Title: Feynman cycles in the Bose gas

Authors: Daniel Ueltschi

Comments: 16 pages

Subj-class: Mathematical Physics; Statistical Mechanics

MSC-class: 82B10; 82B21; 82B26; 82D50

\\

We study the lengths of the cycles formed by trajectories in the Feynman-Kac

representation of the Bose gas. We discuss the occurrence of infinite cycles

and their relation to Bose-Einstein condensation.

\\ ( http://arXiv.org/abs/math-ph/0605002 , 24kb)

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Paper: quant-ph/0605020

Date: Tue, 2 May 2006 01:06:10 GMT (366kb)

Title: The Super-Strong Coupling Regime of Cavity Quantum Electrodynamics

Authors: D. Meiser, P. Meystre

Comments: revtex, 4 pages, 4 figures

\\

We describe a qualitatively new regime of cavity quantum electrodynamics, the

super strong coupling regime. This regime is characterized by atom-field

coupling strengths of the order of the free spectral range of the cavity,

resulting in a significant change in the spatial mode functions of the light

field. It can be reached in practice for cold atoms trapped in an optical

dipole potential inside the resonator. We present a nonperturbative scheme that

allows us to calculate the frequencies and linewidths of the modified field

modes, thereby providing a good starting point for a quantization of the

theory.

\\ ( http://arXiv.org/abs/quant-ph/0605020 , 366kb)

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Paper: quant-ph/0605023

Date: Tue, 2 May 2006 08:59:51 GMT (97kb)

Title: A possible approach to improve sensitivity of Michelson interferometer

Authors: Jian Fu

Comments: 8 pages, 3 figures

\\

We propose a possible approach to achieve an 1/N sensitivity of Michelson

interferometer by using a properly designed random phase modulation. Although,

the $\sqrt{N}$ precision improvement might not be achieved due to the

complication of the random phase modulation, it can help interferometers such

as LIGO to reach higher sensitivity.

\\ ( http://arXiv.org/abs/quant-ph/0605023 , 97kb)

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Paper: quant-ph/0605029

Date: Tue, 2 May 2006 18:48:00 GMT (8kb)

Title: Field fluctuations near a conducting plate and Casimir-Polder forces in

the presence of boundary conditions

Authors: S. Spagnolo, R. Passante and L. Rizzuto

Comments: 10 pages

\\

We consider vacuum fluctuations of the quantum electromagnetic field in the

presence of an infinite and perfectly conducting plate. We evaluate how the

change of vacuum fluctuations due to the plate modifies the Casimir-Polder

potential between two atoms placed near the plate. We use two different methods

to evaluate the Casimir-Polder potential in the presence of the plate. They

also give new insights on the role of boundary conditions in the Casimir-Polder

interatomic potential, as well as indications for possible generalizations to

more complicated boundary conditions.

\\ ( http://arXiv.org/abs/quant-ph/0605029 , 8kb)

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Paper: physics/0605018

Date: Tue, 2 May 2006 12:02:19 GMT (201kb)

Title: Long-lived Bloch oscillations with bosonic Sr atoms and application to

gravity measurement at micrometer scale

Authors: G. Ferrari, N. Poli, F. Sorrentino, G. M. Tino

Subj-class: Atomic Physics

\\

We report on the observation of Bloch oscillations on the unprecedented time

scale of severalseconds. The experiment is carried out with ultra-cold bosonic

strontium-88 loaded into a vertical optical standing wave. The negligible

atom-atom elastic cross section and the absence of spin makes $^{88}$Sr an

almost ideal Bose gas insensitive to typical mechanisms of decoherence due to

thermalization and to external stray fields. The small size enables precision

measurements of forces at micrometer scale. This is a challenge in physics for

studies of surfaces, Casimir effects, and searches for deviations from

Newtonian gravity predicted by theories beyond the standard model.

\\ ( http://arXiv.org/abs/physics/0605018 , 201kb)

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Paper: physics/0605019

Date: Tue, 2 May 2006 15:35:17 GMT (191kb)

Title: Formation of ultracold LiCs molecules

Authors: Stephan D. Kraft, Peter Staanum, Joerg Lange, Leif Vogel, Roland

Wester, Matthias Weidemueller

Comments: 8 pages, 2 figures

Subj-class: Atomic Physics

\\

We present the first observation of ultracold LiCs molecules. The molecules

are formed in a two-species magneto-optical trap and detected by two-photon

ionization and time-of-flight mass spectrometry. The production rate

coefficient is found to be in the range $10^{-18}\unit{cm^3s^{-1}}$ to

$10^{-16}\unit{cm^3s^{-1}}$, at least an order of magnitude smaller than for

other heteronuclear diatomic molecules directly formed in a magneto-optical

trap.

\\ ( http://arXiv.org/abs/physics/0605019 , 191kb)

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Paper: physics/0605017

Date: Tue, 2 May 2006 09:53:20 GMT (285kb)

Title: Soliton control in fading optical lattices

Authors: Yaroslav V. Kartashov, Victor A. Vysloukh, Lluis Torner

Comments: 12 pages, 3 figures, to appear in Optics Letters

Subj-class: Optics

\\

We predict new phenomena, such as soliton steering and soliton fission, in

optical lattices that fade away exponentially along the propagation direction.

Such lattices, featuring tunable decay rates, arise in photorefractive crystals

in the wavelength range 360-400 nm. We show that the predicted phenomena offer

different opportunities for soliton control.

\\ ( http://arXiv.org/abs/physics/0605017 , 285kb)

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Paper: physics/0604082

replaced with revised version Tue, 2 May 2006 19:53:10 GMT (252kb)

Title: Atom interferometer as a selective sensor of rotation or gravity

Authors: B. Dubetsky and M. A. Kasevich

Comments: 21 pages, 4 figures

Subj-class: Atomic Physics

\\ ( http://arXiv.org/abs/physics/0604082 , 231kb)

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Paper: cond-mat/0605085

Date: Wed, 3 May 2006 12:36:57 GMT (41kb)

Title: Anomalous specific heat jump in a two-component ultracold Fermi gas

Authors: Armen Sedrakian, Herbert M\"uther, Artur Polls

Comments: 4 pages, 3 figures

Subj-class: Superconductivity; Statistical Mechanics

\\

We study the temperature-asymmetry phase diagram of a Fermi gas with spin

population imbalance. The imbalance suppresses the pairing in general, and the

temperature dependence of the gap and thermodynamic functions is analogous to

the ordinary BCS state in the high-temperature domain. Anomalies appear in the

low temperature domain: the pairing gap decreases with the temperature and the

entropy of the superfluid is enhanced above the entropy of the normal state.

For large asymmetries the gap shows a reentrance effect - it exists in a

temperature domain bounded by two critical temperatures. This effect leads to

an anomalous second jump in the specific heat of the superfluid, which can be

measured in calorimetric experiments.

\\ ( http://arXiv.org/abs/cond-mat/0605085 , 41kb)

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Paper: cond-mat/0605090

Date: Wed, 3 May 2006 13:17:15 GMT (489kb)

Title: Fast energy transfer mediated by multi-quanta bound states in a

nonlinear quantum lattice

Authors: Cyril Falvo (LPM), Vincent Pouthier (LPM), J. C. Eilbeck

Comments: 28 pages, 8 figures

Proxy: ccsd ccsd-00023659

Subj-class: Other

\\

By using a Generalized Hubbard model for bosons, the energy transfer in a

nonlinear quantum lattice is studied, with special emphasis on the interplay

between local and nonlocal nonlinearity. For a strong local nonlinearity, it is

shown that the creation of v quanta on one site excites a soliton band formed

by bound states involving v quanta trapped on the same site. The energy is

first localized on the excited site over a significant timescale and then

slowly delocalizes along the lattice. As when increasing the nonlocal

nonlinearity, a faster dynamics occurs and the energy propagates more rapidly

along the lattice. Nevertheless, the larger is the number of quanta, the slower

is the dynamics. However, it is shown that when the nonlocal nonlinearity

reaches a critical value, the lattice suddenly supports a very fast energy

propagation whose dynamics is almost independent on the number of quanta. The

energy is transfered by specific bound states formed by the superimposition of

states involving v-p quanta trapped on one site and p quanta trapped on the

nearest neighbour sites, with p=0,..,v-1. These bound states behave as

independent quanta and they exhibit a dynamics which is insensitive to the

nonlinearity and controlled by the single quantum hopping constant.

\\ ( http://arXiv.org/abs/cond-mat/0605090 , 489kb)

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Paper: cond-mat/0605093

Date: Wed, 3 May 2006 16:21:11 GMT (55kb)

Title: Nonergodic Brownian Dynamics and the Fluctuation-Dissipation Theorem

Authors: Jing-Dong Bao, Yi-Zhong Zhuo, Fernando A. Oliveira and Peter H\"anggi

Comments: 4 pages, 2 figures

Subj-class: Statistical Mechanics

\\

Nonergodic Brownian motion is elucidated within the framework of the

generalized Langevin equation. For thermal noise yielding either a vanishing or

a divergent zero-frequency friction strength, the non-Markovian Browninan

dynamics exhibits a riveting, anomalous diffusion behavior being characterized

by a ballistic or possibly also a localized dynamics. As a consequence, such

tailored thermal noise may cause a net acceleration of directed transport in a

rocking Brownian motor. Two notable conditions for the thermal noise are

identified in order to guarantee the fluctuation-dissipation theorem of first

kind.

\\ ( http://arXiv.org/abs/cond-mat/0605093 , 55kb)

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Paper: cond-mat/0605097

Date: Wed, 3 May 2006 17:56:12 GMT (25kb)

Title: Decoherence and Quantum Walks: anomalous diffusion and ballistic tails

Authors: Nikolay Prokof'ev and Philip Stamp

Comments: 4 pages, 1 figure

Subj-class: Other

\\

The common perception is that strong coupling to the environment will always

render the evolution of the system density matrix quasi-classical (in fact,

diffusive) in the long time limit. We present here a counter-example, in which

a particle makes quantum transitions between the sites of a d-dimensional

hypercubic lattice whilst strongly coupled to a bath of two-level systems which

'record' the transitions. The long-time evolution of an initial wave packet

is found to be most unusual: the mean square displacement of the particle

density matrix shows long-range ballitic behaviour, but simultaneously a kind

of weakly-localised behaviour near the origin. This result may have important

implications for the design of quantum computing algorithms, since it describes

a class of quantum walks.

\\ ( http://arXiv.org/abs/cond-mat/0605097 , 25kb)

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Paper: cond-mat/0605099

Date: Wed, 3 May 2006 19:31:18 GMT (709kb)

Title: Strongly Interacting Atoms and Molecules in a 3D Optical Lattice

Authors: Michael K\"ohl, Kenneth G\"unter, Thilo St\"oferle, Henning Moritz,

and Tilman Esslinger

Subj-class: Other

Journal-ref: J. Phys. B: At. Mol. Opt. Phys. 39 (2006) S47-S56

DOI: 10.1088/0953-4075/39/10/S05

\\

We report on the realization of a strongly interacting quantum degenerate gas

of fermionic atoms in a three-dimensional optical lattice. We prepare a

band-insulating state for a two-component Fermi gas with one atom per spin

state per lattice site. Using a Feshbach resonance, we induce strong

interactions between the atoms. When sweeping the magnetic field from the

repulsive side towards the attractive side of the Feshbach resonance we induce

a coupling between Bloch bands leading to a transfer of atoms from the lowest

band into higher bands. Sweeping the magnetic field across the Feshbach

resonance from the attractive towards the repulsive side leads to two-particle

bound states and ultimately to the formation of molecules. From the fraction of

formed molecules we determine the temperature of the atoms in the lattice.

\\ ( http://arXiv.org/abs/cond-mat/0605099 , 832kb)

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Paper (*cross-listing*): nlin.SI/0605006

Date: Tue, 2 May 2006 15:25:16 GMT (21kb)

Title: Nonlinear Dynamics of Quantum Systems and Soliton Theory

Authors: Eldad Bettelheim, Alexander G. Abanov, Paul Wiegmann

Subj-class: Exactly Solvable and Integrable Systems; Other

\\

We show that space-time evolution of one-dimensional fermionic systems is

described by nonlinear equations of soliton theory. We identify a space-time

dependence of a matrix element of fermionic systems related to the {\it

Orthogonality Catastrophe} or {boundary states} with the $\tau$-function of the

modified KP-hierarchy. The established relation allows to apply the apparatus

of soliton theory to the study of non-linear aspects of quantum dynamics. We

also describe a {\it bosonization in momentum space} - a representation of a

fermion operator by a Bose field in the presence of a boundary state.

\\ ( http://arXiv.org/abs/nlin/0605006 , 21kb)

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Paper: quant-ph/0605036

Date: Wed, 3 May 2006 11:20:10 GMT (9kb)

Title: An optimal entanglement criterion for mixed quantum states

Authors: Heinz-Peter Breuer

Comments: 4 pages, no figures

\\

We develop a strong and computationally simple entanglement criterion. The

criterion is based on an elementary positive map Phi which operates on state

spaces with even dimension N >= 4. It is shown that Phi detects many entangled

states with positive partial transposition (PPT) and that it leads to a class

of optimal entanglement witnesses. This implies that there are no other

witnesses which can detect more entangled PPT states. The map Phi yields a

systematic method for the explicit construction of high-dimensional manifolds

of bound entangled states.

\\ ( http://arXiv.org/abs/quant-ph/0605036 , 9kb)

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Paper: physics/0605028

Date: Wed, 3 May 2006 03:13:55 GMT (280kb)

Title: Effect of Magnetization Inhomogeneity on Magnetic Microtraps for Atoms

Authors: S. Whitlock, B. V. Hall, T. Roach, R. Anderson, P. Hannaford and A. I.

Sidorov

Comments: 4 pages, 4 figures

Subj-class: Atomic Physics

\\

We report on the origin of fragmentation of ultracold atoms observed on a

permanent magnetic film atom chip. A novel technique is used to characterize

small spatial variations of the magnetic field near the film surface using

radio frequency spectroscopy of the trapped atoms. Direct observations indicate

the fragmentation is due to a corrugation of the magnetic potential caused by

long range inhomogeneity in the film magnetization. A model which takes into

account two-dimensional variations of the film magnetization is consistent with

the observations.

\\ ( http://arXiv.org/abs/physics/0605028 , 280kb)

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Paper: physics/0605034

Date: Wed, 3 May 2006 16:47:16 GMT (930kb)

Title: Kilohertz-resolution spectroscopy of cold atoms with an optical

frequency comb

Authors: T. M. Fortier, Y. Le Coq, J. E. Stalnaker, D. Ortega, S. A. Diddams,

C. W. Oates and L. Hollberg

Comments: 4 pages, 4 Figures

Subj-class: Atomic Physics

\\

We have performed sub-Doppler spectroscopy on the narrow intercombination

line of cold calcium atoms using the amplified output of a femtosecond laser

frequency comb. Injection locking of a 657-nm diode laser with a femtosecond

comb allows for two regimes of amplification, one in which many lines of the

comb are amplified, and one where a single line is predominantly amplified. The

output of the laser in both regimes was used to perform kilohertz-level

spectroscopy. This experiment demonstrates the potential for high-resolution

absolute-frequency spectroscopy over the entire spectrum of the frequency comb

output using a single high-finesse optical reference cavity.

\\ ( http://arXiv.org/abs/physics/0605034 , 930kb)

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Paper: cond-mat/0605102

Date: Wed, 3 May 2006 20:07:03 GMT (243kb)

Title: Topological defects and the superfluid transition of the $s=1$ spinor

condensate in two dimensions

Authors: Subroto Mukerjee, Cenke Xu, and J. E. Moore

Comments: 4 pages, 2 figures

Subj-class: Other

\\

The $s=1$ spinor Bose condensate at zero temperature supports ferromagnetic

and polar phases that combine magnetic and superfluid ordering. The polar

condensate at finite temperature in two dimensions is shown to have a nematic

or paired superfluid phase with algebraic order in $\exp(2 i \theta)$,where

$\theta$ is the superfluid phase, and no magnetic order. The

Kosterlitz-Thouless transition out of this phase is driven by unbinding of

half-vortices (the spin-disordered version of the combined spin and phase

defects found by Zhou), and the anomalous $8 T_c / \pi$ stiffness jump at the

transition is confirmed in numerical simulations. Experimental observation of

the anomalous jump would be direct confirmation of a phase transition

controlled by unbinding of half-vortices.

\\ ( http://arXiv.org/abs/cond-mat/0605102 , 243kb)

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Paper: cond-mat/0605121

Date: Thu, 4 May 2006 16:51:05 GMT (14kb)

Title: Sweeping from the superfluid to Mott phase in the Bose-Hubbard model

Authors: Ralf Sch\"utzhold, Michael Uhlmann, Yan Xu, Uwe R. Fischer

Comments: 4 pages of RevTex4, 1 figure

Subj-class: Statistical Mechanics

\\

We study the sweep through the quantum phase transition from the superfluid

to the Mott state for the Bose-Hubbard model with a time-dependent tunneling

rate $J(t)$. In the experimentally relevant case of exponential decay,

$J(t)\propto e^{-\gamma t}$, an adapted mean-field expansion for large

fillings~$n$ yields a scaling solution for the fluctuations. This enables us to

analytically calculate the evolution of the number and phase variations

(on-site) and correlations (off-site) for slow ($\gamma\ll\mu$), intermediate,

and fast (non-adiabatic $\gamma\gg\mu$) sweeps, where $\mu$ is the chemical

potential. Finally, we derive the dynamical decay of the off-diagonal

long-range order as well as the temporal shrinkage of the superfluid fraction

in a persistent ring-current setup.

\\ ( http://arXiv.org/abs/cond-mat/0605121 , 14kb)

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Paper: cond-mat/0604638

replaced with revised version Thu, 4 May 2006 18:38:17 GMT (363kb)

Title: Surface tension in population imbalanced unitary Fermi gases

Authors: Theja N. De Silva, Erich J. Mueller

Comments: 4 pages, 4 figures

Subj-class: Other

\\ ( http://arXiv.org/abs/cond-mat/0604638 , 363kb)

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Paper: quant-ph/0602180

replaced with revised version Thu, 4 May 2006 13:15:16 GMT (12kb)

Title: On the detectability of quantum radiation in Bose-Einstein condensates

Authors: Ralf Sch\"utzhold

Comments: 4 pages, 1 figure

\\ ( http://arXiv.org/abs/quant-ph/0602180 , 12kb)

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And if you've read this far, here's one just for fun:

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Paper: physics/0605040

Date: Thu, 4 May 2006 11:13:35 GMT (154kb)

Title: Scattering of a Baseball by a Bat

Authors: Rod Cross and Alan M. Nathan

Comments: Accepted for publication in American Journal of Physics

Subj-class: Popular Physics

\\

A ball can be hit faster if it is projected without spin but it can be hit

farther if it is projected with backspin. Measurements are presented in this

paper of the tradeoff between speed and spin for a baseball impacting a

baseball bat. The results are inconsistent with a collision model in which the

ball rolls off the bat and instead imply tangential compliance in the ball, the

bat, or both. If the results are extrapolated to the higher speeds that are

typical of the game of baseball, they suggest that a curveball can be hit with

greater backspin than a fastball, but by an amount that is less than would be

the case in the absence of tangential compliance.

\\ ( http://arXiv.org/abs/physics/0605040 , 154kb)

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-- ------------------------------------------------------------------------- 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/ -------------------------------------------------------------------------Received on Mon May 08 2006 - 13:25:40 EST

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