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

Date: Sun, 29 Jun 2008 22:46:10 +1000

Date: Sun, 29 Jun 2008 22:46:10 +1000

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

I've finally done it! You're back up to date: there are no emails from

arXiv.org waiting for me to go through.

This week there were 27 preprints and 11 replacements:

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arXiv:0806.3395

Date: Fri, 20 Jun 2008 14:01:19 GMT (203kb)

Title: Creation and detection of a mesoscopic gas in a non-local quantum

superposition

Authors: Christoph Weiss (LKB - Lhomond), Yvan Castin (LKB - Lhomond)

Categories: cond-mat.other

Comments: 4 pages, 1 figure

\\

We investigate the scattering of a quantum matter wave soliton on a barrier

in a one dimensional geometry and we show that it can lead to mesoscopic

Schr\"odinger cat states, where the atomic gas is in a coherent superposition

of being in the half-space to the left of the barrier and being in the

half-space to the right of the barrier. We propose an interferometric method to

reveal the coherent nature of this superposition and we discuss in details the

experimental feasibility.

\\ ( http://arxiv.org/abs/0806.3395 , 203kb)

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arXiv:0806.3402

Date: Fri, 20 Jun 2008 14:20:29 GMT (281kb)

Title: Ionization in a frozen Rydberg gas with attractive or repulsive

potentials

Authors: Matthieu Viteau (LAC), Amodsen Chotia (LAC), Daniel Comparat (LAC),

Duncan A. Tate (LAC), Thomas F. Gallagher (LAC), Pierre Pillet (LAC)

Categories: physics.atom-ph

Comments: 4 pages

\\

We report clear evidence of the role of dipole-dipole interaction in Penning

ionization of Rydberg atoms, leading to the formation of an ultracold plasma.

Penning ionization of np Rydberg Cesium atoms is prevented for states with in n

< 42, which correspond to a repulsive potential, but it does not occur for n

larger than 42, corresponding to an attractive potential. Blackbody radiation

is mostly responsible for the background and initial ionization, although

ion-Rydberg collisions and population transfer due to limited superradiance may

have to be considered.

\\ ( http://arxiv.org/abs/0806.3402 , 281kb)

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arXiv:0806.3780

Date: Mon, 23 Jun 2008 21:44:28 GMT (171kb)

Title: Cold Fermionic Atoms in Traps -- Pairing versus Hund's Rule

Authors: M. Rontani, J. Armstrong, Y. Yu, S. {\AA}berg, S. M. Reimann

Categories: cond-mat.mes-hall

Comments: RevTeX 4.0, 4 pages, 4 colour postscript figures

\\

The microscopic properties of a finite many-body system of few interacting

cold fermionic atoms confined in a harmonic trap are studied by numerical

diagonalization. For repulsive interactions, a strong shell structure

dominates, with Hund's rule acting at its extreme for the mid-shell

configurations. In the attractive case, odd-even oscillations due to pairing

occur simultaneously with deformations in the internal structure of the ground

states, as seen from pair correlation functions.

\\ ( http://arxiv.org/abs/0806.3780 , 171kb)

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arXiv:0806.3806

Date: Tue, 24 Jun 2008 04:33:54 GMT (655kb)

Title: Exactly chaotic shock waves of a Bose-Einstein condensate

Authors: Wenhua Hai, Qianquan Zhu, Shiguang Rong

Categories: cond-mat.other nlin.CD quant-ph

Comments: 4 pages, 2 figures

\\

Classical Smale-horseshoe chaos appeared in a perimetrically driven Duffing

system with the attractive or expulsive parabolic potential and the

nonlinearity. It is demonstrated that such a well-known chaos certainly exists

in the time evolution of one-dimensional (1D) Bose-Einstein condensate (BEC)

experiencing the time-periodic harmonic or inverted-harmonic potential. A

formally exact solution of the time-dependent Gross-Pitaevskii equation (GPE)

is constructed, which describes the matter shock wave with chaotic or periodic

amplitude and phase. When the periodic driving is switched off and the number

of condensed atoms is conserved, the exact shock wave alternately collapses and

grows for the harmonic trapping or propagates with exponentially increased

shock-front speed for the antitrapping. The result suggests an experimental

method for preparing the exponentially accelerated shock waves.

\\ ( http://arxiv.org/abs/0806.3806 , 655kb)

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arXiv:0806.3840

Date: Tue, 24 Jun 2008 09:43:40 GMT (631kb)

Title: Spin-vortex nucleation in a Bose-Einstein condensate by a spin-dependent

rotating trap

Authors: Hiroki Chiba and Hiroki Saito

Categories: cond-mat.other

Comments: 6 pages, 3 figures

\\

A method to produce a spin-dependent rotating potential using near-resonant

circularly polarized laser beams is proposed. It is shown that half-quantum

vortices are nucleated in a spinor Bose-Einstein condensate with an

antiferromagnetic interaction. In contrast to the vortex nucleation in a scalar

BEC, the spin-vortex nucleation occurs at a low rotation frequency ($\simeq 0.1

\omega_\perp$ with $\omega_\perp$ being the radial trap frequency) in a short

nucleation time $\simeq 50$ ms without dissipation. A method for nondestructive

measurement of half-quantum vortices is discussed.

\\ ( http://arxiv.org/abs/0806.3840 , 631kb)

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arXiv:0806.3877

Date: Tue, 24 Jun 2008 12:49:56 GMT (588kb,D)

Title: Optimizing number squeezing when splitting a mesoscopic condensate

Authors: Julian Grond, Joerg Schmiedmayer, Ulrich Hohenester

Categories: cond-mat.other

Comments: 4 pages

\\

We optimize number squeezing when splitting a mesoscopic condensate. A

combination of optimal control theory and the multiconfigurational

time-dependent Hartree method for bosons allowed us to identify a form of the

splitting ramp which drastically outperforms the adiabatic splitting. Our

results can be interpreted in terms of a generic two-mode model mapped onto a

parametric harmonic oscillator. This optimal route to squeezing paves the way

to atom interferometry close to the Heisenberg limit.

\\ ( http://arxiv.org/abs/0806.3877 , 588kb)

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arXiv:0806.3948

Date: Tue, 24 Jun 2008 18:28:03 GMT (119kb)

Title: How the effective boson-boson interaction works in Bose-Fermi mixtures

in periodic geometries

Authors: Giovanni Mazzarella

Categories: cond-mat.other

\\

We study mixtures of spinless bosons and not spin-polarized fermions loaded

in two dimensional optical lattices. We approach the problem of the ground

state stability within the framework of the linear response theory; by the mean

of an iterative procedure, we are able to obtain a relation for the dependence

of boson-boson effective interaction on the absolute temperature of the sample.

Proceeding from such a formula, we write down analyitical expressions for

Supersolid (SS) and Phase Separation (PS) transition temperatures, and plot the

phase diagrams.

\\ ( http://arxiv.org/abs/0806.3948 , 119kb)

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arXiv:0806.3754

Date: Tue, 24 Jun 2008 13:34:12 GMT (693kb)

Title: Quantum critical behavior in strongly interacting Rydberg gases

Authors: Hendrik Weimer, Robert L\"ow, Tilman Pfau, Hans Peter B\"uchler

Categories: quant-ph

Comments: 4 pages, 3 figures

\\

We study the appearance of correlated many-body phenomena in an ensemble of

atoms driven resonantly into a strongly interacting Rydberg state. The ground

state of the Hamiltonian describing the driven system exhibits a second order

quantum phase transition. We derive the critical theory for the quantum phase

transition and show that it describes the properties of the driven Rydberg

system in the saturated regime. We find that the suppression of Rydberg

excitations known as blockade phenomena exhibits an algebraic scaling law with

a universal exponent.

\\ ( http://arxiv.org/abs/0806.3754 , 693kb)

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arXiv:0806.3842

Date: Tue, 24 Jun 2008 09:33:22 GMT (443kb)

Title: Quantum Ratchet Accelerator without a Bichromatic Lattice Potential

Authors: Jiao Wang and Jiangbin Gong

Categories: quant-ph

Comments: 9 pages, 6 figures, submitted to Phys. Rev. E

\\

In a quantum ratchet accelerator system, a linearly increasing directed

current can be dynamically generated without using a biased field. Generic

quantum ratchet acceleration with full classical chaos [Gong and Brumer, Phys.

Rev. Lett. 97, 240602 (2006)] constitutes a new element of quantum chaos and an

interesting violation of a sum rule of classical ratchet transport. Here we

propose a simple quantum ratchet accelerator model that can also generate

linearly increasing quantum current with full classical chaos. This new model

does not require a bichromatic lattice potential. It is based on a variant of

an on-resonance kicked-rotor system, periodically kicked by two optical lattice

potentials of the same lattice constant, but with unequal amplitudes and a

fixed phase shift between them. The dependence of the ratchet current

acceleration rate on the system parameters is studied in detail. The cold-atom

version of our new quantum ratchet accelerator model should be realizable by

introducing slight modifications to current cold-atom experiments.

\\ ( http://arxiv.org/abs/0806.3842 , 443kb)

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arXiv:0806.3909

Date: Tue, 24 Jun 2008 17:10:52 GMT (2154kb)

Title: Blue-detuned evanescent field surface traps for neutral atoms based on

mode interference in ultra-thin optical fibres

Authors: G. Sague, A. Baade and A. Rauschenbeutel

Categories: quant-ph

Comments: 16 pages, 14 figures

\\

We present and analyze a novel concept for blue-detuned evanescent field

surface traps for cold neutral atoms based on two-mode interference in

ultra-thin optical fibres. When two or more transverse modes with the same

frequency co-propagate in the fibre, their different phase velocities cause a

stationary interference pattern to establish. Intensity minima of the

evanescent field at any distance from the fibre surface can be created and an

array of optical microtraps can thus be obtained in the evanescent field. We

discuss three possible combinations of the lowest order modes, yielding traps

at one to two hundred nanometres from the fibre surface which, using a few ten

milliwatts of trapping laser power, have a depth on the order of 1 mK for

caesium atoms and a trapping lifetime exceeding 100 seconds. The resulting

trapping geometry is of particular interest because atoms in such microtrap

arrays will be coupled to any additional field propagating in the fibre via the

evanescent field, thereby realising ensembles of fibre-coupled atoms.

\\ ( http://arxiv.org/abs/0806.3909 , 2154kb)

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arXiv:0806.3829

Date: Tue, 24 Jun 2008 11:56:17 GMT (302kb)

Title: Optical pumping and vibrational cooling of molecules

Authors: Matthieu Viteau (LAC), Amodsen Chotia (LAC), Maria Allegrini (LAC,

CNISM), Nadia Bouloufa (LAC), Olivier Dulieu (LAC), Daniel Comparat (LAC),

Pierre Pillet (LAC)

Categories: physics.atom-ph

Comments: 8 pages

\\

The methods producing cold molecules from cold atoms tend to leave molecular

ensembles with substantial residual internal energy. For instance, Cs2

molecules initially formed via photoassociation of cold Cs atoms are in several

vibrational levels, v, of the electronic ground state. Here we apply a

broadband femtosecond laser that redistributes the vibrational population in

the ground state via a few electronic excitation - spontaneous emission cycles.

The laser pulses are shaped to remove the excitation frequency band of the v =

0 level, preventing re-excitation from that state. We observe a fast and

efficient accumulation, about 70% of the initially detected molecules, in the

lowest vibrational level, v = 0, of the singlet electronic state. The validity

of this incoherent depopulation pumping method is very general and opens

exciting prospects for laser cooling and manipulation of molecules.

\\ ( http://arxiv.org/abs/0806.3829 , 302kb)

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arXiv:0806.3839

Date: Tue, 24 Jun 2008 09:39:27 GMT (22kb)

Title: N-body Efimov states of trapped bosons

Authors: M. Th{\o}gersen, D. V. Fedorov, A. S. Jensen

Categories: physics.atom-ph

\\

We demonstrate the possibility of existence of meta-stable N-body Efimov

states in trapped Bose systems with large scattering length. We calculate

spectra of trapped systems of N=3,4,5,6, and 7 bosons using a stochastic

variational method with a restricted correlated Gaussian basis. For each system

the calculations reveal a series of Efimov states where the energy and the

r.m.s. radius exhibit the characteristic exponential dependence upon the state

number. We also estimate the contribution of these states to the recombination

rate of Bose-Einstein condensates.

\\ ( http://arxiv.org/abs/0806.3839 , 22kb)

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arXiv:0806.3894

Date: Tue, 24 Jun 2008 15:48:14 GMT (645kb,D)

Title: Fractional resonances in the atom-optical delta-kicked accelerator

Authors: M. Saunders, P.L. Halkyard, S.A. Gardiner, and K.J. Challis

Categories: physics.atom-ph

Comments: 20 pages, 8 figures

\\

We consider resonant dynamics in a dilute atomic gas falling under gravity

through a periodically pulsed standing-wave laser field. Our numerical

calculations are based on a Monte Carlo method for an incoherent mixture of

noninteracting plane waves, and show that quantum resonances are highly

sensitive to the relative acceleration between the atomic gas and the pulsed

optical standing wave. For particular values of the atomic acceleration, we

observe fractional resonances. We investigate the effect of the initial atomic

momentum width on the fractional resonances, and quantify the sensitivity of

fractional resonances to thermal effects.

\\ ( http://arxiv.org/abs/0806.3894 , 645kb)

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arXiv:0806.3490

Date: Mon, 23 Jun 2008 18:14:36 GMT (406kb)

Title: Controlled quantum stirring of Bose-Einstein condensates

Authors: Moritz Hiller, Tsampikos Kottos, Doron Cohen

Categories: cond-mat.other

Comments: 12 pages, 8 figures

\\

By cyclic adiabatic change of two control parameters of an optical trap one

can induce a circulating current of condensed bosons. The amount of particles

that are transported per period depends on the "radius" of the cycle, and this

dependence can be utilized in order to probe the interatomic interactions. For

strong repulsive interaction the current can be regarded as arising from a

sequence of Landau-Zener crossings. For weaker interaction one observes either

gradual or coherent mega crossings, while for attractive interaction the

particles are glued together and behave like a classical ball. For the analysis

we use the Kubo approach to quantum pumping with the associated Dirac monopoles

picture of parameter space.

\\ ( http://arxiv.org/abs/0806.3490 , 406kb)

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arXiv:0806.3608

Date: Mon, 23 Jun 2008 03:52:35 GMT (536kb)

Title: Solitons in Bose-Einstein Condensates with time-dependent atomic

scattering length in an expulsive parabolic and complex potential

Authors: Biao Li, Xiao-Fei Zhang, Yu-Qi Li, Yong Chen, W. M. Liu

Categories: cond-mat.other

Comments: 8 pages, 5 figures

\\

We present two families of analytical solutions of the one-dimensional

nonlinear Schr\"{o}dinger equation which describe the dynamics of bright and

dark solitons in Bose-Einstein condensates (BECs) with the time-dependent

interatomic interaction in an expulsive parabolic and complex potential. We

also demonstrate that the lifetime of both a bright soliton and a dark soliton

in BECs can be extended by reducing both the ratio of the axial oscillation

frequency to radial oscillation frequency and the loss of atoms. It is

interested that a train of bright solitons may be excited with a strong enough

background. An experimental protocol is further designed for observing this

phenomenon.

\\ ( http://arxiv.org/abs/0806.3608 , 536kb)

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arXiv:0806.3464

Date: Fri, 20 Jun 2008 20:19:30 GMT (86kb)

Title: Photoassociation spectroscopy of a Spin-1 Bose-Einstein condensate

Authors: C.D. Hamley, E.M. Bookjans, G. Behin-Aein, P. Ahmadi, and M.S. Chapman

Categories: physics.atom-ph

Comments: 5 pages, 4 figures

\\

We report on the high resolution photoassociation spectroscopy of a $^{87}$Rb

spin-1 Bose-Einstein condensate to the $1_\mathrm{g} (P_{3/2}) v = 152$ excited

molecular states. We demonstrate the use of spin dependent photoassociation to

experimentally identify the molecular states and their corresponding initial

scattering channel. These identifications are in excellent agreement with the

eigenvalues of a hyperfine-rotational Hamiltonian. Using the observed spectra

we estimate the change in scattering length and identify photoassociation laser

light frequency ranges that maximize the change in the spin-dependent

mean-field interaction energy.

\\ ( http://arxiv.org/abs/0806.3464 , 86kb)

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arXiv:0806.3466

Date: Fri, 20 Jun 2008 20:28:18 GMT (861kb)

Title: Dark dynamic acousto-optic ring lattices for ultracold atoms

Authors: N. Houston, E. Riis, A. S. Arnold

Categories: physics.optics physics.atom-ph

Comments: 6 pages, 5 figures, hyperlinked references

\\

We demonstrate the optical generation of dynamic dark optical ring lattices,

which do not require Laguerre-Gauss beams, large optical coherence lengths or

interferometric stability. Simple control signals lead to spatial modulation

and reproducible rotation, offering manifold possibilities for complex dynamic

ring lattices. In conjunction with a magnetic trap, these scanned 2D intensity

distributions from a single laser beam will enable precision trapping and

manipulation of ultracold species using blue-detuned light. The technique is

ideal for azimuthal ratchet, Mott insulator and persistent current experiments

with quantum degenerate gases.

\\ ( http://arxiv.org/abs/0806.3466 , 861kb)

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arXiv:0806.3991

Date: Tue, 24 Jun 2008 21:17:21 GMT (129kb)

Title: Low-energy resonances and bound states of aligned bosonic and fermionic

dipoles

Authors: K. Kanjilal and D. Blume

Categories: cond-mat.other

Comments: 4 pages, 4 figures

\\

The low-energy scattering properties of two aligned identical bosonic and

identical fermionic dipoles are analyzed. Generalized scattering lengths are

determined as functions of the dipole moment and the scattering energy. Near

resonance, where a new bound state is being pulled in, all non-vanishing

generalized scattering lengths diverge, with the $a_{00}$ and $a_{11}$

scattering lengths being dominant for identical bosons and identical fermions,

respectively, near both broad and narrow resonances. Implications for the

energy spectrum and the eigenfunctions of trapped two-dipole systems and for

pseudo-potential treatments are discussed.

\\ ( http://arxiv.org/abs/0806.3991 , 129kb)

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arXiv:0806.4106

Date: Wed, 25 Jun 2008 19:20:16 GMT (24kb)

Title: Formation of vortices in a dense Bose-Einstein condensate

Authors: V.P. Barros, Ch. Moseley, A. Gammal, K. Ziegler

Categories: cond-mat.other

Comments: 10 pages, 4 figures

\\

A relaxation method is employed to study a rotating dense Bose-Einstein

condensate beyond Thomas-Fermi approximation. We use a slave-boson model to

describe the strongly interacting condensate and derive a generalized

non-linear Schr\"odinger equation with kinetic term for the rotating

condensate. In comparison with previous calculations, based on Thomas-Fermi

approximation, significant improvements are found in regions, where the

condensate in a trap potential is not smooth. The critical angular velocity of

the vortex formation is higher than in the Thomas-Fermi prediction.

\\ ( http://arxiv.org/abs/0806.4106 , 24kb)

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arXiv:0806.4002

Date: Wed, 25 Jun 2008 15:46:47 GMT (768kb)

Title: Quantum theory of ultracold atom-ion collisions

Authors: Zbigniew Idziaszek, Tommaso Calarco, Paul S. Julienne, and Andrea

Simoni

Categories: physics.atom-ph

Comments: 5 pages,3 figures

\\

We study atom-ion scattering in the ultracold regime. To this aim, an

analytical model based on the multichannel quantum defect formalism is

developed and compared to close-coupled numerical calculations. We investigate

the occurrence of magnetic Feshbach resonances focusing on the specific 40Ca+ -

Na system. The presence of several resonances at experimentally accessible

magnetic fields should allow the atom-ion interaction to be precisely tuned. A

fully quantum-mechanical study of charge exchange processes shows that

charge-exchange rates should remain small even in the presence of resonance

effects. Most of our results can be cast in a system-independent form and are

important for the realization of the charge-neutral ultracold systems.

\\ ( http://arxiv.org/abs/0806.4002 , 768kb)

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arXiv:0806.4192

Date: Wed, 25 Jun 2008 20:21:22 GMT (73kb)

Title: Theory of spin nematic to spin-Peierls quantum phase transition in

ultracold spin-1 atoms in optical lattices

Authors: Christoph M. Puetter, Michael J. Lawler, Hae-Young Kee

Categories: cond-mat.str-el

Comments: 7 pages, 4 figures

\\

We present a theory of the anisotropy tuned quantum phase transition between

spin nematic and spin-Peierls phases in S=1 systems with significant

bi-quadratic exchange interactions. Based on quantum Monte Carlo studies on

finite size systems, [K. Harada et al., J. Phys. Soc. Jpn. 76, 013703 (2007)]

it has been proposed that this phase transition is second order with new

deconfined fractional excitations that are absent in either of the two phases

[T. Grover and T. Senthil, Phys. Rev. Lett. 98, 247202 (2007)]. The possibility

of a weak first order transition, however, cannot be ruled out. To elucidate

the nature of the transition, we construct a large-N SO(3N) model for this

phase transition and find in the $N\to\infty$ limit that the transition is

generically of first order. Furthermore, in the extreme anisotropic

1-dimensional limit, we find no sign of a disordered spin nematic phase, as

originally suggested by Chubukov [A. V. Chubukov, Phys. Rev. B, 43, 3337

(1990)] based on a spin-1 bond operator (two-site cluster) approach.

Predictions for $^{23}$Na atoms trapped in an optical lattice, where this

quantum phase transition naturally arises, are discussed.

\\ ( http://arxiv.org/abs/0806.4192 , 73kb)

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arXiv:0806.4283

Date: Thu, 26 Jun 2008 18:01:30 GMT (58kb)

Title: Synchronization and Dephasing of Many-Body States in Optical Lattices

Authors: M. B. Hastings and L. S. Levitov

Categories: cond-mat.str-el

\\

We introduce an approach to describe quantum-coherent evolution of a system

of cold atoms in an optical lattice triggered by a change in superlattice

potential. Using a time-dependent mean field description, we map the problem to

a strong coupling limit of previously studied time-dependent BCS model. We

compare the mean field dynamics to a simulation using light-cone methods and

find reasonable agreement for numerically accessible times. The mean field

model is integrable, and gives rise to a rich behavior, in particular to beats

and recurrences in the order parameter, as well as singularities in the

momentum distribution, directly measureable in cold atom experiment.

\\ ( http://arxiv.org/abs/0806.4283 , 58kb)

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arXiv:0806.4310

Date: Thu, 26 Jun 2008 13:10:05 GMT (125kb)

Title: Strong dissipation inhibits losses and induces correlations in cold

molecular gases

Authors: N. Syassen, D. M. Bauer, M. Lettner, T. Volz, D. Dietze, J. J.

Garcia-Ripoll, J. I. Cirac, G. Rempe, S. D\"urr

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

Journal-ref: Science 320, 1329 (2008)

DOI: 10.1126/science.1155309

\\

Atomic quantum gases in the strong-correlation regime offer unique

possibilities to explore a variety of many-body quantum phenomena. Reaching

this regime has usually required both strong elastic and weak inelastic

interactions, as the latter produce losses. We show that strong inelastic

collisions can actually inhibit particle losses and drive a system into a

strongly-correlated regime. Studying the dynamics of ultracold molecules in an

optical lattice confined to one dimension, we show that the particle loss rate

is reduced by a factor of 10. Adding a lattice along the one dimension

increases the reduction to a factor of 2000. Our results open up the

possibility to observe exotic quantum many-body phenomena with systems that

suffer from strong inelastic collisions.

\\ ( http://arxiv.org/abs/0806.4310 , 125kb)

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arXiv:0806.4325

Date: Thu, 26 Jun 2008 15:33:51 GMT (131kb)

Title: Harmonic Stability Analysis of the 2D Square and Hexagonal Bravais

Lattices for a Finite--Ranged Repulsive Pair Potential. Consequence for a 2D

System of Ultracold Composite Bosons

Authors: D.J. Papoular

Categories: cond-mat.other

Comments: 8 pages, 5 figures

\\

We consider a classical, two-dimensional system of identical particles which

interact via a finite-ranged, repulsive pair potential. We assume that the

system is in a crystalline phase. We calculate the normal vibrational modes of

a two-dimensional square Bravais lattice, first analytically within the

nearest-neighbour approximation, and then numerically, relaxing the preceding

hypothesis. We show that, in the harmonic approximation, the excitation of a

transverse vibrational mode leads to the breakdown of the square lattice. We

next study the case of the hexagonal Bravais lattice and we show that it can be

stable with respect to lattice vibrations. We give a criterion determining

whether or not it is stable in the nearest-neighbour approximation. Finally, we

apply our results to a two-dimensional system of composite bosons and infer

that the crystalline phase of such a system, if it exists, corresponds to a

hexagonal lattice.

\\ ( http://arxiv.org/abs/0806.4325 , 131kb)

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arXiv:0806.4378

Date: Thu, 26 Jun 2008 19:42:06 GMT (11kb)

Title: Vortex pseudomomentum and dissipation in a superfluid vortex lattice

Authors: H. M. Cataldo

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

Comments: 9 pages, no figures

Journal-ref: J. Phys. A: Math. Theor. 41 (2008) 295501 (9pp)

DOI: 10.1088/1751-8113/41/29/295501

\\

We propose an alternative approach to the dissipative vortex dynamics

occurring in a superfluid vortex lattice at finite temperatures. Focusing upon

the pseudomomentum of a vortex and its surrounding quasiparticles, we derive an

equation of motion which, in spite of yielding the same evolution as the usual

one for massless vortices, does not involve the vortex mass. This picture could

provide further insights into the controversy about the nature of the vortex

mass.

\\ ( http://arxiv.org/abs/0806.4378 , 11kb)

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arXiv:0806.4258

Date: Thu, 26 Jun 2008 07:54:34 GMT (1234kb)

Title: Photon echoes generated by reversing magnetic field gradients in a

rubidium vapour

Authors: G. H\'etet, M. Hosseini, B. Sparkes, D. Oblak, P. K. Lam and B. C.

Buchler

Categories: quant-ph

\\

We propose a photon echo quantum memory scheme using detuned Raman coupling

to long lived ground states. In contrast to previous 3-level schemes based on

controlled reversible inhomogeneous broadening that use sequences of

$\pi$-pulses, the scheme does not require accurate control of the coupling

dynamics to the ground states. We present a proof of principle experimental

realization of our proposal using rubidium atoms in a warm vapour cell. The

Raman resonance line is broadened using a magnetic field that varies linearly

along the direction of light propagation. Inverting the magnetic field gradient

rephases the atomic dipoles and re-emits the light pulse in the forward

direction.

\\ ( http://arxiv.org/abs/0806.4258 , 1234kb)

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arXiv:0806.4337

Date: Thu, 26 Jun 2008 15:17:37 GMT (1776kb)

Title: Low-density, one dimensional quantum gases in the presence of a

localised attractive potential

Authors: J. Goold, D. O Donoghue and Th. Busch

Categories: quant-ph

Comments: 15 pages, 9 figures

\\

We investigate low-density, quantum-degenerate gases in the presence of a

localised attractive potential in the centre of a one-dimensional harmonic

trap.The attractive potential is modelled using a parameterised delta-function,

allowing us to determine all single particle eigenfunctions analytically. From

these we calculate the ground state many-body properties for a system of

spin-polarised fermions and, using the Bose-Fermi mapping theorem, extend the

results to strongly interacting bosonic systems. We discuss the single particle

densities, the pair correlation functions, the reduced single particle density

matrices and the momentum distributions as a function of particle number and

strength of the attractive point potential. As an important experimental

observable, we place special emphasis on spatial coherence properties of such

samples.

\\ ( http://arxiv.org/abs/0806.4337 , 1776kb)

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arXiv:0712.2256

replaced with revised version Thu, 19 Jun 2008 22:45:18 GMT (160kb)

Title: New type of Bose-Einstein condensation of cold atoms with effective

spin-orbit interactions

Authors: Tudor Stanescu and Victor Galitski

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

Comments: 4 pages, 2 color figures (new Fig. 2)

\\ ( http://arxiv.org/abs/0712.2256 , 160kb)

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arXiv:0804.2705

replaced with revised version Thu, 19 Jun 2008 23:27:14 GMT (304kb)

Title: Phase Separation in Bose-Fermi-Fermi Mixtures as a Probe of Fermi

Superfluidity

Authors: S. G. Bhongale and Han Pu

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

\\ ( http://arxiv.org/abs/0804.2705 , 304kb)

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arXiv:0712.2571

replaced with revised version Tue, 24 Jun 2008 10:24:37 GMT (559kb,D)

Title: Ultracold atomic gas in non-Abelian "magnetic" fields: the quantum Hall

effect supremacy

Authors: N. Goldman, A. Kubasiak, P. Gaspard and M. Lewenstein

Categories: cond-mat.mes-hall

Comments: 4 pages, 3 figures: latest version with updated acknowledgments

\\ ( http://arxiv.org/abs/0712.2571 , 559kb)

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arXiv:0803.0507

replaced with revised version Tue, 24 Jun 2008 12:45:36 GMT (851kb,D)

Title: Numerical observation of Hawking radiation from acoustic black holes in

atomic Bose-Einstein condensates

Authors: Iacopo Carusotto, Serena Fagnocchi, Alessio Recati, Roberto Balbinot,

Alessandro Fabbri

Categories: cond-mat.other gr-qc hep-th

Comments: Version 2 with enlarged text and several new figures

\\ ( http://arxiv.org/abs/0803.0507 , 851kb)

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arXiv:0805.2708

replaced with revised version Tue, 24 Jun 2008 11:08:35 GMT (405kb,D)

Title: Modulation transfer spectroscopy in atomic rubidium

Authors: D. J. McCarron, S. A. King and S. L. Cornish

Categories: physics.atom-ph

Comments: 14 pages, 7 figures

\\ ( http://arxiv.org/abs/0805.2708 , 405kb)

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arXiv:0804.0355

replaced with revised version Mon, 23 Jun 2008 09:48:25 GMT (20kb)

Title: Pair-Breaking in Rotating Fermi Gases

Authors: Michael Urban and Peter Schuck

Categories: cond-mat.other

Comments: 4 pages, 2 figures; v2: discussion clarified, typos corrected, one

reference added

\\ ( http://arxiv.org/abs/0804.0355 , 20kb)

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arXiv:0805.2708

replaced with revised version Mon, 23 Jun 2008 14:57:31 GMT (452kb)

Title: Modulation transfer spectroscopy in atomic rubidium

Authors: D. J. McCarron, S. A. King and S. L. Cornish

Categories: physics.atom-ph

Comments: 14 pages, 7 figures

\\ ( http://arxiv.org/abs/0805.2708 , 452kb)

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arXiv:0804.1547

replaced with revised version Wed, 25 Jun 2008 01:02:19 GMT (572kb)

Title: Supersolid state of ultracold fermions in an optical lattice

Authors: Akihisa Koga, Takuji Higashiyama, Kensuke Inaba, Seiichiro Suga, and

Norio Kawakami

Categories: cond-mat.supr-con

Comments: 5 pages, 4 figures

Journal-ref: J. Phys. Soc. Jpn. 77, 073602 (2008)

DOI: 10.1143/JPSJ.77.073602

\\ ( http://arxiv.org/abs/0804.1547 , 572kb)

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arXiv:0802.4055

replaced with revised version Wed, 25 Jun 2008 15:49:33 GMT (264kb)

Title: Bifurcations, order, and chaos in the Bose-Einstein condensation of

dipolar gases

Authors: Patrick K\"oberle, Holger Cartarius, Toma\v{z} Fab\v{c}i\v{c}, J\"org

Main, G\"unter Wunner

Categories: quant-ph nlin.CD

Comments: 10 pages, 4 figures

\\ ( http://arxiv.org/abs/0802.4055 , 264kb)

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arXiv:0710.1848

replaced with revised version Thu, 26 Jun 2008 10:15:10 GMT (355kb,D)

Title: Long wavelength spin dynamics of ferromagnetic condensates

Authors: Austen Lamacraft

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

Comments: arXiv version contains additional Section V relevant to the

experiment of Vengalattore et. al. (Phys. Rev. Lett. 100, 170403, (2008))

Journal-ref: Phys. Rev. A 77, 063622 (2008)

\\ ( http://arxiv.org/abs/0710.1848 , 355kb)

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arXiv:0803.1889

replaced with revised version Thu, 26 Jun 2008 09:38:10 GMT (260kb)

Title: Atom-Pair Tunneling in Optical Lattices

Authors: J.-Q. Liang, J.-L. Liu, W.-D. Li, Z.-J. Li

Categories: cond-mat.other quant-ph

\\ ( http://arxiv.org/abs/0803.1889 , 260kb)

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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 Jul 04 2008 - 08:31:07 EST

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