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

Date: Fri, 15 Jun 2007 21:37:00 +1000 (EST)

Date: Fri, 15 Jun 2007 21:37:00 +1000 (EST)

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

So I've found myself with some time at Singapore airport on the way back

to Brisbane, so I thought I may as well be constructive... here is an

early arXiv email!

One thing I should point out: something funny happened with the

Wednesday cond-mat mailing. I went back and trawled through the

abstracts on the web, but it is possible I may have missed something.

If I missed your papers, please let me know and I'll put it in next

week.

Another busy week with 31 new abstracts, and 9 replaced.

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arXiv:0706.1128

Date: Fri, 8 Jun 2007 08:13:11 GMT (360kb)

Title: Dipole Oscillations in Bose - Fermi Mixture in the Time-Dependent

Grosspitaevskii and Vlasov equations

Authors: Tomoyuki Maruyama, George F. Bertsch

Categories: cond-mat.other

Comments: 17 pages text, and 15 figures

\\

We study the dipole collective oscillations in the bose-fermi mixture using a

dynamical time-dependent approach, which are formulated with the time-dependent

Gross-Pitaevskii equation and the Vlasov equation. We find big difference in

behaviors of fermion oscillation between the time-dependent approach and usual

approaches such as the random-phase approximation and the sum-rule approach.

While the bose gas oscillates monotonously, the fermion oscillation shows a

beat and a damping. When the amplitude is not minimal, the dipole oscillation

of the fermi gas cannot be described with a simple center-of-mass motion.

\\ ( http://arxiv.org/abs/0706.1128 , 360kb)

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arXiv:0706.1181

Date: Fri, 8 Jun 2007 13:30:57 GMT (30kb)

Title: Polarization and angular distribution of the radiation emitted in

laser-assisted recombination

Authors: Saverio Bivona, Giovanni Bonanno, Riccardo Burlon, Claudio Leone

Categories: cond-mat.other

Comments: 5 pages, 3 figures

\\

The effect of an intense external linear polarized radiation field on the

angular distributions and polarization states of the photons emitted during the

radiative recombination is investigated. It is predicted, on symmetry grounds,

and corroborated by numerical calculations of approximate recombination rates,

that emission of elliptically polarized photons occurs when the momentum of the

electron beam is not aligned to the direction of the oscillating field.

Moreover, strong modifications to the angular distributions of the emitted

photons are induced by the external radiation field.

\\ ( http://arxiv.org/abs/0706.1181 , 30kb)

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arXiv:0706.1205

Date: Fri, 8 Jun 2007 16:55:06 GMT (155kb)

Title: Single particle spectrum of resonant population imbalanced Fermi gases

Authors: Francesco Fumarola, Erich J. Mueller

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

Comments: 4 pages, 4 figures

\\

We use a T-matrix approximation to calculate the single particle spectrum of

the normal state of a gas of Fermionic atoms at low temperature.

In the strongly interacting regime of the polarized gas, we find that the

spectrum is separated in two branches, leading to a double-peaked

radiofrequency spectral feature.

\\ ( http://arxiv.org/abs/0706.1205 , 155kb)

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arXiv:0706.1230

Date: Fri, 8 Jun 2007 18:54:23 GMT (40kb)

Title: Three bodies bind even when two do not: Efimov states and Fano

resonances in atoms and nuclei

Authors: A. R. P. Rau

Categories: quant-ph

Comments: 2 figures

\\

Efimov's prediction more than three decades ago that three-body bound states

can exist when the pairwise attractions do not bind or only support weakly

bound states of a pair, has remained unconfirmed till just the past year. This

lecture provides the pedagogical background for recent work on Efimov states in

neutron-rich nuclei done with I. Mazumdar (TIFR) and V. S. Bhasin (Delhi

University), and published in Phys. Rev. Lett. 97, 062503 (2006). Both these

nuclear systems and recent observations of cold cesium atoms provide the first

clear evidence for the existence of Efimov states.

\\ ( http://arxiv.org/abs/0706.1230 , 40kb)

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arXiv:0706.1170

Date: Fri, 8 Jun 2007 12:24:14 GMT (179kb)

Title: A lattice of microtraps for ultracold atoms based on patterned magnetic

films

Authors: R. Gerritsma, S. Whitlock, T. Fernholz, H. Schlatter, J. A. Luigjes,

J.-U. Thiele, J. B. Goedkoop and R. J. C. Spreeuw

Categories: physics.atom-ph

Comments: 7 pages, 7 figures

\\

We have realized a two dimensional permanent magnetic lattice of

Ioffe-Pritchard microtraps for ultracold atoms. The lattice is formed by a

single 300 nm magnetized layer of FePt, patterned using optical lithography.

Our magnetic lattice consists of more than 15000 tightly confining microtraps

with a density of 1250 traps/mm$^2$. Simple analytical approximations for the

magnetic fields produced by the lattice are used to derive relevant trap

parameters. We load ultracold atoms into at least 30 lattice sites at a

distance of approximately 10 $\mu$m from the film surface. The present result

is an important first step towards quantum information processing with neutral

atoms in magnetic lattice potentials.

\\ ( http://arxiv.org/abs/0706.1170 , 179kb)

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arXiv:0706.1253

Date: Fri, 8 Jun 2007 20:50:01 GMT (303kb)

Title: Finite temperature phase diagram of trapped Fermi gases with population

imbalance

Authors: Wei Zhang and L.-M. Duan

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

Comments: 9 pages, 7 figures

\\

We consider a trapped Fermi gas with population imbalance at finite

temperatures and map out the detailed phase diagram across a wide Feshbach

resonance. We take the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state into

consideration and minimize the thermodynamical potential to ensure stability.

Under the local density approximation, we conclude that a stable LOFF state is

present only on the BCS side of the Feshbach resonance, but not on the BEC side

or at unitarity. Furthermore, even on the BCS side, a LOFF state is restricted

at low temperatures and in a small region of the trap, which makes a direct

observation of LOFF state a challenging task.

\\ ( http://arxiv.org/abs/0706.1253 , 303kb)

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arXiv:0706.1296

Date: Mon, 11 Jun 2007 18:48:08 GMT (1363kb)

Title: Hyperspherical approach to the four-body problem

Authors: Nirav P. Mehta, Seth T. Rittenhouse, Jose P. D'Incao, Chris H. Greene

Categories: cond-mat.other

Comments: 10 pages, 3 figures. To be published in: Atomic Structure and

Collision Processes Publisher: Narosa

\\

The four-particle system is the simplest few-body system containing the

fundamental physics involved in ultracold fermionic gases. We have made recent

efforts to solve the quantum four-body problem in the adiabatic hyperspherical

representation. Our approach yields a set of coupled potential curves that can

in turn be solved for all elastic and inelastic processes. These rates may play

an important role in the lifetime of molecules in ultracold fermi gases. We

believe this will lead to a deeper understanding of ultracold fermi systems and

the physics of the BCS-BEC crossover.

\\ ( http://arxiv.org/abs/0706.1296 , 1363kb)

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arXiv:0706.1297

Date: Sat, 9 Jun 2007 09:26:24 GMT (42kb)

Title: Lattice bosons in quartic confinement

Authors: R. Ramakumar and A. N. Das

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

Comments: 11 pages including figures

\\

We present a theoretical study of bose condensation of non-interacting bosons

in finite lattices in quartic potentials in one, two, and three dimensions. We

investigate dimensionality effects and quartic potential effects on single

boson density of energy states, condensation temperature, condensate fraction,

and specific heat. The results obtained are compared with corresponding results

for lattice bosons in harmonic traps.

\\ ( http://arxiv.org/abs/0706.1297 , 42kb)

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arXiv:0706.1322

Date: Sat, 9 Jun 2007 17:14:01 GMT (9kb)

Title: Demonstration that the local density approximation for trapped systems

is exact in the thermodynamic limit

Authors: Nadia Sandoval-Figueroa and V\'{\i}ctor Romero-Roch\'{\i}n

Categories: cond-mat.stat-mech

Comments: Submitted to Physical Review Letters, 10 pages

\\

We demonstrate that the so-called ``local density approximation'' used to

calculate thermodynamic properties of systems confined by external potentials

is exact in the thermodynamic limit. We prove our result for classical and

quantum systems as well. We point out that this procedure also validates the

introduction of generalized variables in inhomogeneous fluids that replace the

usual volume and pressure, and in terms of which the equation of state of

confined ultracold gases must be expressed.

\\ ( http://arxiv.org/abs/0706.1322 , 9kb)

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arXiv:0706.1390

Date: Mon, 11 Jun 2007 02:14:36 GMT (356kb)

Title: Strong atom-field coupling for Bose-Einstein condensates in an optical

cavity on a chip

Authors: Yves Colombe, Tilo Steinmetz, Guilhem Dubois, Felix Linke, David

Hunger, Jakob Reichel

Categories: quant-ph

\\

An optical cavity enhances the interaction between atoms and light, and the

rate of coherent atom-photon coupling can be made larger than all decoherence

rates of the system. For single atoms, this strong coupling regime of cavity

quantum electrodynamics (cQED) has been the subject of spectacular experimental

advances, and great efforts have been made to control the coupling rate by

trapping and cooling the atom towards the motional ground state, which has been

achieved in one dimension so far. For N atoms, the three-dimensional ground

state of motion is routinely achieved in atomic Bose-Einstein

condensates(BECs), but although first experiments combining BECs and optical

cavities have been reported recently, coupling BECs to strong-coupling cavities

has remained an elusive goal. Here we report such an experiment, which is made

possible by combining a new type of fibre-based cavity with atom chip

technology. This allows single-atom cQED experiments with a simplified setup,

but moreover realizes the new situation of N atoms in a cavity each of which is

identically and strongly coupled to the cavity mode. The BEC can be positioned

deterministically anywhere within the cavity and localized entirely within a

single antinode of the standing-wave cavity field. This gives rise to a

controlled, tunable coupling rate, as we confirm experimentally. We study the

back action of a cavity transmission measurement as a function of the coupling

rate and find no measurable heating for strongly coupled BECs. The spectrum of

the coupled atoms-cavity system, which we map out over a wide range of atom

numbers and cavity-atom detunings, shows vacuum Rabi splittings exceeding 20

GHz, as well as anticrossings. The system is suitable as a light-matter quantum

interface for quantum information.

\\ ( http://arxiv.org/abs/0706.1390 , 356kb)

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arXiv:0706.1431

Date: Mon, 11 Jun 2007 10:15:11 GMT (319kb)

Title: Observation of squeezed light with 10dB quantum noise reduction

Authors: Henning Vahlbruch, Moritz Mehmet, Nico Lastzka, Boris Hage, Simon

Chelkowski, Alexander Franzen, Stefan Gossler, Karsten Danzmann and Roman

Schnabel

Categories: quant-ph

Comments: 10 pages, 4 figures

\\

Squeezing of light's quantum noise requires temporal rearranging of photons.

This again corresponds to creation of quantum correlations between individual

photons. Squeezed light is a non-classical manifestation of light with great

potential in high-precision quantum measurements, for example in the detection

of gravitational waves. Equally promising applications have been proposed in

quantum communication. However, after 20 years of intensive research doubts

arose whether strong squeezing can ever be realized as required for eminent

applications. Here we show experimentally that strong squeezing of light's

quantum noise is possible. We reached a benchmark squeezing factor of 10 in

power (10dB). Thorough analysis reveals that even higher squeezing factors will

be feasible in our setup.

\\ ( http://arxiv.org/abs/0706.1431 , 319kb)

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arXiv:0706.1465

Date: Mon, 11 Jun 2007 13:22:48 GMT (17kb)

Title: Supercurrents in an atom-molecule gas in an optical ring lattice

Authors: T. Wang J. Javanainen S. F. Yelin

Categories: quant-ph

Comments: 5 pages, 4 figures, submitted to PRA

\\

Atom and molecule currents in a Fermi gas in the neighborhood of a Feshbach

resonance are studied in a one-dimensional optical ring lattice by directly

diagonalizing small models. A rotational analogy of flux quantization is used

to show that fraction of the current is carried by particles with twice the

mass of an atom, which suggests pairing and superfluidity.

\\ ( http://arxiv.org/abs/0706.1465 , 17kb)

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arXiv:0706.1470

Date: Mon, 11 Jun 2007 13:40:53 GMT (19kb)

Title: Fast mode of rotating atoms in one-dimensional lattice rings

Authors: T. Wang and S. F. Yelin

Categories: quant-ph

Comments: 4 pages, 5 figures

\\

We study the rotation of atoms in one-dimensional lattice rings. In

particular, the "fast mode", where the ground state atoms rotate faster than

the stirring rotating the atoms, is studied both analytically and numerically.

The conditions for the transition to the fast mode are found to be very

different from that in continuum rings. We argue that these transition

frequencies remain unchanged for bosonic condensates described in a mean field.

We show that Fermionic interaction and filling factor have a significant effect

on the transition to the fast mode, and Pauli principle may suppress it

altogether.

\\ ( http://arxiv.org/abs/0706.1470 , 19kb)

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arXiv:0706.1295

Date: Sat, 9 Jun 2007 09:03:50 GMT (19kb)

Title: Reaction Time of a Group of Physics Students

Authors: Charu Saxena, Rini Kaur, P.Arun

Categories: physics.ed-ph

Comments: 10 pages, 4 figures

\\

The reaction time of a group of students majoring in Physics is reported

here. Strong co-relation between fatigue, reaction time and performance have

been seen and may be useful for academicians and administrators responsible of

working out time-tables, course structures, students counsellings etc.

\\ ( http://arxiv.org/abs/0706.1295 , 19kb)

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arXiv:0706.1741

Date: 12 June 2007

Title: Breakdown of the Thomas Fermi approximation for polarized Fermi gases

Authors: Rajdeep Sensarma, William Schneider, Roberto B. Diener, Mohit Randeria

Categories: physics.ed-ph

Comments: 10 pages, 4 figures

\\

We use Bogoliubov de-Gennes theory to show that the commonly used

Thomas-Fermi approximation (TFA) can fail in describing polarized unitary gases

in anisotropic harmonic traps. We find a magnetized superfluid region inside

the trap, with order parameter oscillations, even though there is no such

stable bulk phase. This leads to magnetization profiles that deviate from

contours of constant potential energy. We determine how this violation scales

with trap anisotropy and number of particles, and show that we are able to

account for important differences between the MIT and Rice experiments.

\\ ( http://arxiv.org/abs/0706.1741 , 355kb)

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arXiv:0706.1741 [ps, pdf, other] :

Title: Breakdown of the Thomas Fermi approximation for polarized Fermi gases

Authors: Rajdeep Sensarma, William Schneider, Roberto B. Diener, Mohit

Randeria

Comments: 4 pages 3 figures

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arXiv:0706.1627

Date: Tue, 12 Jun 2007 08:29:41 GMT (117kb)

Title: Rectified momentum transport for a kicked Bose-Einstein Condensate

Authors: Mark Sadgrove, Munekazu Horikoshi, Tetsuo Sekimura, Ken'ichi Nakagawa

Categories: quant-ph

Comments: 4 Pages, 4 Figures. Accepted for publication Phys. Rev. Lett. June

2007

\\

We report the experimental observation of rectified momentum transport for a

Bose-Einstein Condensate kicked at the Talbot time (quantum resonance) by an

optical standing wave. Atoms are initially prepared in a superposition of the 0

and -2*hbar*kl momentum states using an optical pi/2 pulse. By changing the

relative phase of the superposed states, a momentum current in either direction

along the standing wave may be produced. We offer an interpretation based on

matter wave interference, showing that the observed effect is uniquely quantum.

\\ ( http://arxiv.org/abs/0706.1627 , 117kb)

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arXiv:0706.1674

Date: Tue, 12 Jun 2007 12:50:38 GMT (8kb)

Title: Fluctuations of the Casimir-Polder force between an atom and a

conducting wall

Authors: R. Messina and R. Passante

Categories: quant-ph

Comments: 6 pages

\\

We consider the quantum fluctuations of the Casimir-Polder force between a

neutral atom and a perfectly conducting wall in the ground state of the system.

In order to obtain the atom-wall force fluctuation we first define an operator

directly associated to the force experienced by the atom considered as a

polarizable body in an electromagnetic field, and we use a time-averaged force

operator in order to avoid ultraviolet divergences appearing in the fluctuation

of the force. This time-averaged force operator takes into account that any

measurement involves a finite time. We also calculate the Casimir-Polder force

fluctuation for an atom between two conducting walls. Experimental

observability of these Casimir-Polder force fluctuations is also discussed, as

well as the dependence of the relative force fluctuation on the duration of the

measurement.

\\ ( http://arxiv.org/abs/0706.1674 , 8kb)

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arXiv:0706.1587

Date: Mon, 11 Jun 2007 22:07:15 GMT (523kb)

Title: Resonances of the Quantum $\delta$-Kicked Accelerator

Authors: V. Ramareddy, G. Behinaein, I. Talukdar, P. Ahmadi, G. S. Summy

Categories: physics.atom-ph

Comments: 4 pages, 4 figures

\\

We report the observation of high order resonances of the quantum

$\delta$-kicked accelerator using a BEC kicked by a standing wave of light. The

signature of these resonances is the existence of quantum accelerator modes.

For the first time quantum accelerator modes were seen near 1/4 and 1/3 of the

Talbot time. Using a BEC enabled us to study the detailed structure of the

modes and resonances which are related to the fractional Talbot effect. We

present a general theory for this system and apply it to predict the behavior

of the accelerator modes.

\\ ( http://arxiv.org/abs/0706.1587 , 523kb)

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arXiv:0706.1608

Date: Tue, 12 Jun 2007 05:33:50 GMT (865kb)

Title: Magneto-optical Trapping of Cadmium

Authors: K.-A. Brickman, M.-S. Chang, M. Acton, A. Chew, D. Matsukevich, P. C.

Haljan, V. S. Bagnato, and C. Monroe

Categories: physics.atom-ph

Comments: 8 pages, 11 figures

\\

We report the laser-cooling and confinement of Cd atoms in a magneto-optical

trap, and characterize the loading process from the background Cd vapor. The

trapping laser drives the 1S0-1P1 transition at 229 nm in this two-electron

atom and also photoionizes atoms directly from the 1P1 state. This

photoionization overwhelms the other loss mechanisms and allows a direct

measurement of the photoionization cross section, which we measure to be

2(1)x10^(-16)cm^(2) from the 1P1 state. When combined with nearby laser-cooled

and trapped Cd^(+) ions, this apparatus could facilitate studies in ultracold

interactions between atoms and ions.

\\ ( http://arxiv.org/abs/0706.1608 , 865kb)

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arXiv:0706.1797

Date: Tue, 12 Jun 2007 22:24:13 GMT (10kb)

Title: Soluble Models of Strongly Interacting Ultracold Gas Mixtures in Tight

Waveguides

Authors: M.D. Girardeau and A. Minguzzi

Categories: cond-mat.other

Comments: 4 pages, no figures, revtex4

\\

A generalized Fermi-Bose mapping method is used to determine the exact ground

states of several models of mixtures of strongly interacting ultracold gases in

tight waveguides, which are generalizations of the Tonks-Girardeau (TG) gas (1D

Bose gas with point hard cores) and fermionic Tonks-Girardeau (FTG) gas (1D

spin-aligned Fermi gas with infinitely strong zero-range attractions). Three

are two-component mixtures of TG and/or ideal Fermi gases with TG interactions

between the two components, three are two-component mixtures of FTG and/or

ideal Bose gases with FTG interactions between the two components, and several

more involve some aspects of both TG and FTG interactions. Exact results are

given for density profiles in a harmonic trap and for single-particle density

matrices and momentum distributions.

\\ ( http://arxiv.org/abs/0706.1797 , 10kb)

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arXiv:0706.1840

Date: Wed, 13 Jun 2007 07:39:19 GMT (180kb)

Title: Vortex pump for dilute Bose-Einstein condensates

Authors: Mikko Mottonen, Ville Pietila, Sami M. M. Virtanen

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

Comments: 4 pages, 3 figures

\\

The formation of vortices by topological phase engineering has been realized

experimentally to create the first two- and four-quantum vortices in dilute

atomic Bose-Einstein condensates [A. E. Leanhardt et al., Phys. Rev. Lett. 89,

190403 (2002)]. We consider a similar system, but in addition to the

Ioffe-Pritchard magnetic trap we employ an additional hexapole field. By

controlling cyclicly the strengths of these magnetic fields, we show that a

fixed amount of vorticity can be added to the condensate in each cycle. In an

adiabatic operation of this vortex pump, the appearance of vortices into the

condensate is interpreted as the accumulation of a local Berry phase. Our

design can be used as an experimentally realizable vortex source for possible

vortex-based applications of dilute Bose-Einstein condensates.

\\ ( http://arxiv.org/abs/0706.1840 , 180kb)

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arXiv:0706.1850

Date: Wed, 13 Jun 2007 09:05:13 GMT (44kb)

Title: Casimir-Lifshitz force out of thermal equilibrium

Authors: Mauro Antezza, Lev P. Pitaevskii, Sandro Stringari, Vitaly B. Svetovoy

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

Comments: 24 pages, 5 figures

\\

We study the Casimir-Lifshitz interaction out of thermal equilibrium, with

particular attention devoted to the surface-surface and surface-atom

configurations. A systematic investigation of the contributions to the force

coming from the propagating and evanescent components of the electromagnetic

radiation is performed. The large distance behaviors of such interactions is

discussed, and both analytical and numerical results are compared with the

equilibrium ones. A detailed analysis of the crossing between the

surface-surface and the surface-rarefied body, and finally the surface-atom

force is shown, and a complete derivation and discussion of the recently

predicted non-additivity effects and new asymptotic behaviors is presented.

\\ ( http://arxiv.org/abs/0706.1850 , 44kb)

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arXiv:0706.1854

Date: Wed, 13 Jun 2007 09:18:53 GMT (55kb)

Title: Two-particle binding energy of interacting Bose gases

Authors: K. Morawetz M. M{\"a}nnel, M. Schreiber and P. Lipavsk\'y

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

Comments: 4 pages

\\

The pole of the two-particle T-matrix including the influence of the

surrounding medium for an interacting Bose gas is analyzed. The phase diagram

of the Bose-Einstein condensation (BEC) depending on the temperature, density,

scattering length, and momentum is derived from this pole. The critical

momentum for the occurrence of superfluidity is obtained in this way. As a new

observation a two-particle binding energy is reported intimately connected with

the occurrence of the BEC. It is suggested that this might have cosmological

consequences on the dark energy problem.

\\ ( http://arxiv.org/abs/0706.1854 , 55kb)

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arXiv:0706.1870

Date: Wed, 13 Jun 2007 10:49:01 GMT (305kb)

Title: Stability of coreless vortices in ferromagnetic spinor Bose-Einstein

condensates

Authors: V. Pietila, M. Mottonen, and S. M. M. Virtanen

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

Comments: 7 pages, 6 figures

\\

We study the energetic and dynamic stability of coreless vortices in

nonrotated spin-1 Bose-Einstein condensates, trapped with a three-dimensional

optical potential and a Ioffe-Pritchard field. The stability of stationary

vortex states is investigated by solving the corresponding Bogoliubov

equations. We show that the quasiparticle excitations corresponding to

axisymmetric stationary states can be taken to be eigenstates of angular

momentum in the axial direction. Our results show that coreless vortex states

can occur as local or global minima of the condensate energy or become

energetically or dynamically unstable depending on the parameters of the

Ioffe-Pritchard field. The experimentally most relevant coreless vortex state

containing a doubly quantized vortex in one of the hyperfine spin components

turned out to have very non-trivial stability regions, and especially a

quasiperiodic dynamic instability region which corresponds to splitting of the

doubly quantized vortex.

\\ ( http://arxiv.org/abs/0706.1870 , 305kb)

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arXiv:0706.1821

Date: Wed, 13 Jun 2007 05:04:47 GMT (403kb)

Title: Holographic storage of multiple coherence gratings in a Bose-Einstein

condensate

Authors: Yutaka Yoshikawa, Kazuyuki Nakayama, Yoshio Torii, and Takahiro Kuga

Categories: physics.atom-ph

Comments: 5 pages, 4 figures

\\

We demonstrate superradiant conversion between a two-mode collective atomic

state and a single-mode light field in an elongated cloud of Bose-condensed

atoms. Two off-resonant write beams induce superradiant Raman scattering,

producing two independent coherence gratings with a different wave vector in

the cloud. By applying phase-matched read beams after a controllable delay, the

gratings can be selectively converted into the light field also in a

superradiant way. Due to the large cooperativity parameter and the small

velocity width of the condensate, a high conversion efficiency of $> 70$ % and

a long storage time of $> 120$ $\mu$s were achieved.

\\ ( http://arxiv.org/abs/0706.1821 , 403kb)

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arXiv:0706.1903

Date: Wed, 13 Jun 2007 13:59:02 GMT (341kb)

Title: Avoiding radiation pressure in an optical cavity interacting with

ultra-cold atoms

Authors: Simone Bux, Gordon Krenz, Sebastian Slama, Claus Zimmermann, Philippe

W. Courteille

Categories: physics.atom-ph physics.optics

Comments: 6 pages, 7 figures

\\

The combination of ultra-cold atomic clouds stored in the light field of

optical cavities provides a powerful model system for the development of new

types of laser cooling and for studying cooperative phenomena. These

experiments critically depend on the precise tuning of an incident pump laser

with respect to a cavity resonance. Here, we present a simple and reliable

experimental tuning scheme based on a two-mode laser spectrometer. The scheme

uses a first laser for probing higher-order transversal modes of the cavity

having an intensity minimum near the cavity's optical axis, where the atoms are

confined. In this way the cavity resonance is observed without exposing the

atoms to unwanted radiation pressure. A second laser, which is phase-locked to

the first one and tuned close to a fundamental cavity mode drives the coherent

atom-field dynamics.

\\ ( http://arxiv.org/abs/0706.1903 , 341kb)

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arXiv:0706.2078

Date: Thu, 14 Jun 2007 10:26:14 GMT (62kb)

Title: Nonclassical dynamics of Bose condensates in an optical lattice in the

superfluid regime

Authors: Roberto Franzosi (Dipartimento di fisica Universita' di Firenze and

CNR-INFM)

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

Comments: 5 pages, 4 figures

Journal-ref: Phys. Rev. A, 75, 053610 (2007)

\\

A condensate in an optical lattice, prepared in the ground state of the

superfluid regime, is stimulated first by suddenly increasing the optical

lattice amplitude and then, after a waiting time, by abruptly decreasing this

amplitude to its initial value. Thus the system is first taken to the Mott

regime and then back to the initial superfluid regime. We show that, as a

consequence of this nonadiabatic process, the system falls into a configuration

far from equilibrium whose superfluid order parameter is described in terms of

a particular superposition of Glauber coherent states that we derive. We also

show that the classical equations of motion describing the time evolution of

this system are inequivalent to the standard discrete nonlinear Schreodinger

equations. By numerically integrating such equations with several initial

conditions, we show that the system loses coherence, becoming insulating.

\\ ( http://arxiv.org/abs/0706.2078 , 62kb)

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arXiv:0706.2082

Date: Thu, 14 Jun 2007 10:25:49 GMT (445kb)

Title: Elementary Excitations of a Bose-Einstein Condensate in an Effective

Magnetic Field

Authors: D. R. Murray (1), P. \"Ohberg (2), Dami\'{a} Gomila (3) and Stephen M.

Barnett (1) ((1) SUPA, University of Strathclyde, Glasgow, UK (2) SUPA,

Heriot-Watt University, Edinburgh, UK (3) IFISC, CSIC-UIB, Campus Universitat

Illes Balears, Palma de Mallorca, Spain)

Categories: cond-mat.other

Comments: 8 pages, 4 figures

\\

We calculate the low energy elementary excitations of a Bose-Einstein

Condensate in an effective magnetic field. The field is created by the

interplay between light beams carrying orbital angular momentum and the trapped

atoms. We examine the role of the homogeneous magnetic field, familiar from

studies of rotating condensates, and also investigate spectra for vector

potentials with a more general radial dependence. We discuss the instabilities

which arise and how these may be manifested.

\\ ( http://arxiv.org/abs/0706.2082 , 445kb)

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arXiv:0706.2133

Date: Thu, 14 Jun 2007 14:43:06 GMT (74kb)

Title: Boson-Fermion pairing in Bose-Fermi mixtures on 1D optical lattices

Authors: X. Barillier-Pertuisel, S. Pittel, L.Pollet, P. Schuck

Categories: cond-mat.other

Comments: submitted to Phys. Rev. A

\\

Boson-fermion pairing is considered in a discrete environment of bosons and

fully spin-polarized fermions, coupled via an attractive Bose-Fermi Hubbard

Hamiltonian in one dimension. The results of the T-matrix approximation for

particles of equal mass and at double half filling are compared with the

results of exact diagonalization and with Quantum Monte Carlo results.

Satisfactory agreement for most quantities is found. The appearance of a

stable, weak-coupling pairing mode is also confirmed.

\\ ( http://arxiv.org/abs/0706.2133 , 74kb)

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arXiv:0706.2161

Date: Thu, 14 Jun 2007 17:02:52 GMT (81kb)

Title: General Hubbard model for strongly interacting fermions in an optical

lattice and its phase detection

Authors: L.-M. Duan

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

Comments: 5 pages, 4 figures

\\

Based on consideration of the system symmetry and its Hilbert space, we show

that strongly interacting fermions in an optical lattice or superlattice can be

generically described by a lattice resonance Hamiltonian. The latter can be

mapped to a general Hubbard model with particle assisted tunneling rates. We

investigate the model under population imbalance and show the attractive and

the repulsive models have the same complexity in phase diagram under the

particle-hole mapping. Using this mapping, we propose an experimental method to

detect possible exotic superfluid/magnetic phases for this system.

\\ ( http://arxiv.org/abs/0706.2161 , 81kb)

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The replacements:

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arXiv:0704.0440

replaced with revised version Fri, 8 Jun 2007 16:08:33 GMT (94kb)

Title: Dynamics of a quantum phase transition in a ferromagnetic Bose-Einstein

condensate

Authors: Bogdan Damski and Wojciech H. Zurek

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

Comments: 4 pages & figures, significantly improved presentation with respect

to the first submission

Report-no: LAUR-07-1400

\\ ( http://arxiv.org/abs/0704.0440 , 94kb)

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arXiv:0706.0629

replaced with revised version Fri, 8 Jun 2007 11:40:41 GMT (9kb)

Title: Quasi localization and quasi mobility edge for the light fermionic atoms

mixed with the heavy ones

Authors: E. Kogan

Categories: cond-mat.dis-nn

Comments: 4 pages, 1 figure, latex

\\ ( http://arxiv.org/abs/0706.0629 , 9kb)

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arXiv:cond-mat/0702645

replaced with revised version Mon, 11 Jun 2007 11:32:32 GMT (202kb)

Title: Fast initialization of a high-fidelity quantum register using optical

superlattices

Authors: B. Vaucher and S. R. Clark and U. Dorner and D. Jaksch

Categories: cond-mat.other quant-ph

Comments: 22 pages, 9 figures, IOP style. Revised version to appear in NJP

\\ ( http://arxiv.org/abs/cond-mat/0702645 , 202kb)

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arXiv:cond-mat/0703526

replaced with revised version Mon, 11 Jun 2007 01:26:57 GMT (47kb)

Title: Local Density Functional Theory for Superfluid Fermionic Systems: The

Unitary Gas

Authors: Aurel Bulgac

Categories: cond-mat.supr-con nucl-th

Comments: 4 pages, 3 eps figures + online appendix, significant changes

including comparison with new ab initio results

\\ ( http://arxiv.org/abs/cond-mat/0703526 , 47kb)

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arXiv:cond-mat/0703610

replaced with revised version Mon, 11 Jun 2007 16:22:56 GMT (61kb)

Title: Dynamics of one-dimensional Bose liquids: Andreev-like reflection at

Y-junctions and absence of the Aharonov-Bohm effect

Authors: Akiyuki Tokuno, Masaki Oshikawa, Eugene Demler

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

Comments: 4pages, 3figures, revised version, a few brief summaries added

\\ ( http://arxiv.org/abs/cond-mat/0703610 , 61kb)

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arXiv:0704.3959

replaced with revised version Mon, 11 Jun 2007 15:33:06 GMT (799kb)

Title: Optical Devices for Cold Atoms and Bose-Einstein Condensates

Authors: Naceur Gaaloul (PPM, LSAMA), Amine Jaouadi (PPM, LSAMA), Mourad

Telmini (LSAMA), Laurence Pruvost (LAC), Eric Charron (PPM)

Categories: quant-ph

Comments: Proceedings of the International Spectroscopy Conference ISC-2007,

Sousse, Tunisia

\\ ( http://arxiv.org/abs/0704.3959 , 799kb)

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arXiv:quant-ph/0403128

replaced with revised version Tue, 12 Jun 2007 08:52:03 GMT (66kb)

Title: Casimir-Polder forces: A non-perturbative approach

Authors: Stefan Yoshi Buhmann, Ho Trung Dung, Ludwig Kn\"{o}ll, Dirk-Gunnar

Welsch

Categories: quant-ph

Comments: 23 pages, 3 figures, additional misprints corrected

Journal-ref: Physical Review A 70 (5), 052117 (2004)

DOI: 10.1103/PhysRevA.70.052117

\\ ( http://arxiv.org/abs/quant-ph/0403128 , 66kb)

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arXiv:quant-ph/0603193

replaced with revised version Tue, 12 Jun 2007 08:12:34 GMT (11kb)

Title: Microscopic origin of Casimir-Polder forces

Authors: Stefan Yoshi Buhmann, Hassan Safari, Dirk-Gunnar Welsch, and Ho Trung

Dung

Categories: quant-ph

Comments: 10 pages, 0 figures

Journal-ref: Open Systems and Information Dynamics 13 (4), 427 (2006)

DOI: 10.1007/s11080-006-9024-0

\\ ( http://arxiv.org/abs/quant-ph/0603193 , 11kb)

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arXiv:0706.1854

replaced with revised version Thu, 14 Jun 2007 12:57:21 GMT (55kb)

Title: Two-particle binding energy of interacting Bose gases

Authors: K. Morawetz M. M{\"a}nnel, M. Schreiber and P. Lipavsk\'y

Categories: cond-mat.other astro-ph cond-mat.stat-mech cond-mat.str-el

physics.atom-ph

Comments: 4 pages

\\ ( http://arxiv.org/abs/0706.1854 , 55kb)

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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 Fri Jun 15 2007 - 21:37:00 EST

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