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

Date: Tue, 24 Feb 2009 20:29:00 +1000

Date: Tue, 24 Feb 2009 20:29:00 +1000

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

It almost seems like ancient history... there were 36 new preprints and 9

replacements.

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arXiv:0812.3718

Date: Fri, 19 Dec 2008 07:54:47 GMT (208kb)

Title: Universal three-body bound states in planar atomic wave guides

Authors: Ludovic Pricoupenko (LPTMC), Paolo Pedri (LPTMC, LPL)

Categories: cond-mat.other

\\

Shallow trimers are found for mixtures of two atomic species strongly trapped

in a quasi two-dimensional atomic wave guide. The binding energies are

functions of the 2D-scattering length and of the mass ratio and can be thus

tuned by various ways. These universal trimers are composed of two identical

non interacting particles and of a third particle of the other species.

Depending on the statistics of the two identical particles, the trimers have an

odd (fermions) or even (bosons) internal angular momentum. These results permit

to draw conclusions on the stability issue for the quasi-2D gaseous phase of

heteronuclear dimers.

\\ ( http://arxiv.org/abs/0812.3718 , 208kb)

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arXiv:0812.3767

Date: Fri, 19 Dec 2008 12:01:32 GMT (107kb)

Title: Cold atoms in double-well optical lattices

Authors: V.I. Yukalov and E.P. Yukalova

Categories: cond-mat.mes-hall cond-mat.stat-mech

Comments: Latex file, 24 pages, 3 figures

Journal-ref: Phys. Rev. A 78 (2008) 063610-10

\\

Cold atoms, loaded into an optical lattice with double-well sites, are

considered. Pseudospin representation for an effective Hamiltonian is derived.

The system in equilibrium displays two phases, ordered and disordered. The

second-order phase transition between the phases can be driven either by

temperature or by changing the system parameters. Collective pseudospin

excitations have a gap disappearing at the phase-transition point. Dynamics of

atoms is studied, when they are loaded into the lattice in an initially

nonequilibrium state. It is shown that the temporal evolution of atoms,

contrary to their equilibrium thermodynamics, cannot be described in the

mean-field approximation, since it results in a structurally unstable dynamical

system, but a more accurate description is necessary taking account of

attenuation effects.

\\ ( http://arxiv.org/abs/0812.3767 , 107kb)

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arXiv:0812.3660

Date: Fri, 19 Dec 2008 19:11:02 GMT (149kb)

Title: Alkaline-Earth Atoms as Few-Qubit Quantum Registers

Authors: Alexey V. Gorshkov, Ana Maria Rey, Andrew J. Daley, Martin M. Boyd,

Jun Ye, Peter Zoller, Mikhail D. Lukin

Categories: quant-ph

Comments: 4 pages, 2 figures

\\

We propose and analyze a novel approach to quantum information processing, in

which multiple qubits can be encoded and manipulated using electronic and

nuclear degrees of freedom associated with individual alkaline-earth atoms

trapped in an optical lattice. Specifically, we describe how the qubits within

each register can be individually manipulated and measured with sub-wavelength

optical resolution. We also show how such few-qubit registers can be coupled to

each other in optical superlattices via conditional tunneling to form a

scalable quantum network. Finally, potential applications to quantum

computation and precision measurements are discussed.

\\ ( http://arxiv.org/abs/0812.3660 , 149kb)

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arXiv:0812.3701

Date: Fri, 19 Dec 2008 03:40:56 GMT (102kb)

Title: Is a rubidium cell with long decay time always useful for generating a

non-classical photon pair?

Authors: Qun-Feng Chen, Xiao-Song Lu, Bao-Sen Shi, and Guang-Can Guo

Categories: quant-ph

Comments: 3 pages, 5 figures

\\

We experimentally find an interesting and unexpected thing: a rubidium cell

with long decay time can not be used to generate a non-classical correlated

photon pair via the D2 transition of $^{87}$Rb using four-wave mixing

configuration [Opt. Express {\bf 16}, 21708 (2008)]. In this work, we give a

detail theoretical analysis on the EIT of hot $^{87}$Rb with different ground

decay time, which shows a probable reason why a rubidium cell with long decay

time is not a useful candidate for preparation of a non-classical photon pair

via the D2 transition. The simulations agree well with the experimental

results. We believe our find is very instructive to such kind of research.

\\ ( http://arxiv.org/abs/0812.3701 , 102kb)

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arXiv:0812.3844

Date: Fri, 19 Dec 2008 16:41:29 GMT (68kb)

Title: Two-dimensional weakly interacting Bose gas: equation of state

Authors: G.E. Astrakharchik, J. Boronat, J. Casulleras, I.L. Kurbakov, and

Yu.E. Lozovik

Categories: quant-ph cond-mat.other

Comments: 2 figures, 2 tables

\\

The equation of state of a weakly interacting two-dimensional Bose gas is

studied at zero temperature by means of quantum Monte Carlo methods. Going down

to as low densities as na^2 ~ 10^{-67} permits us for the first time to obtain

agreement on beyond mean-field level between predictions of perturbative

methods and direct many-body numerical simulation, thus providing an answer to

the fundamental question of the equation of state of a two-dimensional dilute

Bose gas. We also show that the measure of the frequency of a breathing

collective oscillation in a trap at very low densities can be used to test the

universal equation of state of a two-dimensional Bose gas.

\\ ( http://arxiv.org/abs/0812.3844 , 68kb)

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arXiv:0812.3052 (*cross-listing*)

Date: Tue, 16 Dec 2008 13:33:51 GMT (21kb)

Date (revised v2): Wed, 17 Dec 2008 10:29:59 GMT (21kb)

Title: Dephasing of entangled atoms as an improved test of quantum gravity

Authors: Mark S. Everitt, Martin L. Jones, Benjamin T. H. Varcoe

Categories: gr-qc quant-ph

Comments: 4 pages, 2 figures

\\

In a recent article Wang et al. (Class. Quantum Grav. 23 (2006) L59),

demonstrated that phase of a particle fluctuated due to interactions with

random deviations of a conformal gravitational field. Furthermore they

demonstrated that atom interferometers were sensitive to these fluctuations and

that sensitivity to Planck scale effects could be achieved with a sufficiently

sensitive interferometer. In this paper we demonstrate that a class of

entangled states, the N-atom Greenberger-Horne-Zeilinger (GHZ) states, provide

a better scaling than atom interferometry and that current experiments are

capable of making a significant impact in this field. We outline an experiment

which uses atomic beams of rubidium atoms excited to Rydberg states that

undergo controlled collisions in high-Q microwave resonators in a sequence that

makes the resulting state highly sensitive to conformal field fluctuations. We

show that a significant advance in sensitivity is possible.

\\ ( http://arxiv.org/abs/0812.3052 , 21kb)

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arXiv:0812.3940

Date: Mon, 22 Dec 2008 12:35:05 GMT (1028kb)

Title: Trapping cold atoms using surface-grown carbon nanotubes

Authors: P. G. Petrov, S. Machluf, S. Younis, R. Macaluso, T. David, B. Hadad,

Y. Japha, M. Keil, E. Joselevich, R. Folman

Categories: cond-mat.other

\\

We present a feasibility study for loading cold atomic clouds into magnetic

traps created by single-wall carbon nanotubes grown directly onto dielectric

surfaces. We show that atoms may be captured for experimentally sustainable

nanotube currents, generating trapped clouds whose densities and lifetimes are

sufficient to enable detection by simple imaging methods. This opens the way

for a novel type of conductor to be used in atomchips, enabling atom trapping

at sub-micron distances, with implications for both fundamental studies and for

technological applications.

\\ ( http://arxiv.org/abs/0812.3940 , 1028kb)

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arXiv:0812.3945

Date: Sat, 20 Dec 2008 07:51:43 GMT (58kb)

Title: Quantum liquid crystals in imbalanced Fermi gas: fluctuations and

fractional vortices in Larkin-Ovchinnikov states

Authors: Leo Radzihovsky, Ashvin Vishwanath

Categories: cond-mat.supr-con

Comments: 4 pages, 1 figure

\\

We develop a low-energy model of a unidirectional Larkin-Ovchinnikov (LO)

state. Because the underlying rotational and translational symmetries are

broken spontaneously, this gapless superfluid is a smectic liquid crystal, that

exhibits fluctuations that are qualitatively stronger than in a conventional

superfluid, thus requiring a fully nonlinear description of its Goldstone

modes. Consequently, at nonzero temperature the LO superfluid is an algebraic

phase even in 3d. It exhibits half-integer vortex-dislocation defects, whose

unbinding leads to transitions to a superfluid nematic and other phases. In 2d

at nonzero temperature, the LO state is always unstable to a charge-4 nematic

superfluid. We expect this superfluid liquid-crystal phenomenology to be

realizable in imbalanced resonant Fermi gases trapped isotropically.

\\ ( http://arxiv.org/abs/0812.3945 , 58kb)

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arXiv:0812.3969

Date: Sat, 20 Dec 2008 14:39:32 GMT (62kb)

Title: Quantized vortices and superflow in arbitrary dimensions: Structure,

energetics and dynamics

Authors: Paul M. Goldbart and Florin Bora (University of Illinois at

Urbana-Champaign)

Categories: cond-mat.stat-mech

Comments: 35 pages, 7 figures

\\

The structure and energetics of superflow around quantized vortices, and the

motion inherited by these vortices from this superflow, are explored in the

general setting of the superfluidity of helium-four in arbitrary dimensions.

The vortices may be idealized as objects of co-dimension two, such as

one-dimensional loops and two-dimensional closed surfaces, respectively, in the

cases of three- and four-dimensional superfluidity. By using the analogy

between vorticial superflow and Ampere-Maxwell magnetostatics, the equilibrium

superflow containing any specified collection of vortices is constructed. The

energy of the superflow is found to take on a simple form for vortices that are

smooth and asymptotically large, compared with the vortex core size. The motion

of vortices is analyzed in general, as well as for the special cases of

hyper-spherical and weakly distorted hyper-planar vortices. In all dimensions,

vortex motion reflects vortex geometry. In dimension four and higher, this

includes not only extrinsic but also intrinsic aspects of the vortex shape,

which enter via the first and second fundamental forms of classical geometry.

For hyper-spherical vortices, which generalize the vortex rings of three

dimensional superfluidity, the energy-momentum relation is determined. Simple

scaling arguments recover the essential features of these results, up to

numerical and logarithmic factors.

\\ ( http://arxiv.org/abs/0812.3969 , 62kb)

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arXiv:0812.3997

Date: Sat, 20 Dec 2008 20:51:02 GMT (266kb)

Title: Phase transition to a Bose-Einstein condensate with atomic polaritons

Authors: A. P. Alodjants, A. Yu. Leksin, S. M. Arakelian, J. Nipper, U. Vogl,

M. Weitz

Categories: cond-mat.mes-hall

Comments: 12 pages, 10 postscript figures, REVTeX 4, presented to Phys. Rev. A

\\

We study a critical phenomenon for atomic polaritons in a cavity for the

interaction of two-level atoms with quantized optical radiation in the strong

coupling regime. We derive an expression for the critical temperature when a

Bardeen-Cooper-Schrieffer (BCS)-type phase transition between the normal and a

superfluid state occurs. Such a transition results in the appearance of a

macroscopic polarization of atomic medium at non-zero frequency. Important is

that the critical temperature of the phase transition is essentially dependent

on photon numbers in the cavity. We predict the densities at which the

crossover from BCS state to Bose-Einstein condensate (BEC) state takes place

for a two dimensional gas of polaritons in the cavity. A prerequisite for such

a phase transition is a fully thermalised system. We also describe the

experiment on atom-light interaction with rubidium atoms in an ultrahigh buffer

gas chamber. The lifetime of excited state rubidium atoms in the buffer gas

chamber is studied. Further, an observed detuning dependence of the saturated

lineshape is interpreted as evidence for thermal equilibrium of coupled

atom-light states.

\\ ( http://arxiv.org/abs/0812.3997 , 266kb)

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arXiv:0812.4049

Date: Sun, 21 Dec 2008 18:17:48 GMT (2835kb,D)

Title: The dynamics of quantum vortices in a toroidal trap

Authors: Peter Mason, Natalia G. Berloff

Categories: cond-mat.other

Comments: Submitted to Phys. Rev. A. 18 pages, 22 figures

\\

The dynamics of quantum vortices in a two-dimensional annular condensate are

considered by numerically simulating the Gross-Pitaevskii equation. Families of

solitary wave sequences are reported, both without and with a persistent flow,

for various values of interaction strength. It is shown that in the toroidal

geometry the dispersion curve of solutions is much richer than in the cases of

a semi-infinite channel or uniform condensate studied previously. In

particular, the toroidal condensate is found to have states of single vortices

at the same position and circulation that move with different velocities. The

stability of the solitary wave sequences for the annular condensate without a

persistent flow are also investigated by numerically evolving the solutions in

time. In addition, the interaction of vortex-vortex pairs and vortex-antivortex

pairs is considered and it is demonstrated that the collisions are either

elastic or inelastic depending on the magnitude of the angular velocity. The

similarities and differences between numerically simulating the

Gross-Pitaevskii equation and using a point vortex model for these collisions

are elucidated.

\\ ( http://arxiv.org/abs/0812.4049 , 2835kb)

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arXiv:0812.4075

Date: Mon, 22 Dec 2008 01:17:28 GMT (462kb)

Title: Vortex sheet in rotating two-component Bose-Einstein condensates

Authors: Kenichi Kasamatsu and Makoto Tsubota

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

Comments: 8 pages, 7 figures

\\

We investigate vortex states of immiscible two-component Bose-Einstein

condensates under rotation. When the imbalance of the intracomponent parameter

is small, each component makes up of winding chains of singly quantized

vortices, vortex sheet, instead of periodic vortex lattices. We discuss the

details of this structure through numerical simulations of the Gross-Pitaevskii

equations and the analytical estimate of the sheet distance, determined by the

competition between the surface tension of the domain wall and the kinetic

energy of the superflow via quantized vortices. By comparing the several length

scales in this system, the phase diagram of the vortex state is obtained.

\\ ( http://arxiv.org/abs/0812.4075 , 462kb)

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arXiv:0812.4155

Date: Mon, 22 Dec 2008 11:29:55 GMT (88kb,D)

Title: Self-organization in dissipative optical lattices

Authors: G. Baris Bagci and Ugur Tirnakli

Categories: cond-mat.stat-mech

Comments: 9 pages, 1 fig

\\

We show that the transition from Gaussian to the q-Gaussian distributions

occurring in atomic transport in dissipative optical lattices can be

interpreted as self-organization by recourse to a modified version of

Klimontovich's S-theorem. As a result, we find that self-organization is

possible in the transition regime, only where the second moment <p^{2}> is

finite. Therefore, the nonadditivity parameter q is confined within the range

1<q<5/3, although whole spectrum of q values i.e., 1<q<3, is considered

theoretically possible. The range of q values obtained from the modified

S-theorem is also confirmed by the experiments carried out by Douglas et al.

[Phys. Rev. Lett. 96, 110601 (2006)].

\\ ( http://arxiv.org/abs/0812.4155 , 88kb)

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arXiv:0812.4174

Date: Mon, 22 Dec 2008 20:49:36 GMT (320kb)

Title: Fragmented many-body ground states in a single trap for bosons with

long-range interactions

Authors: Philipp Bader and Uwe R. Fischer

Categories: cond-mat.other

Comments: 4 pages of RevTex3, 3 figures

\\

We investigate whether the many-body states of bosons in a generalized

two-mode model with arbitrary long-range interactions and single-particle

orbitals are coherent (condensed) or fragmented. It is demonstrated that

fragmentation can take place in a single trap for positive values of the

interaction couplings, implying that the system is potentially stable.

Furthermore, the degree of fragmentation is shown to be insensitive to small

perturbations on the single-particle level.

\\ ( http://arxiv.org/abs/0812.4174 , 320kb)

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arXiv:0812.4195

Date: Mon, 22 Dec 2008 14:21:06 GMT (1229kb)

Title: Fermionized photons in an array of driven dissipative nonlinear cavities

Authors: Iacopo Carusotto, Dario Gerace, Hakan Tureci, Simone De Liberato,

Cristiano Ciuti, Atac Imamoglu

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

\\

We theoretically investigate the optical response of a one-dimensional array

of strongly nonlinear optical microcavities. When the optical nonlinearity is

much larger than both losses and inter-cavity tunnel coupling, the

non-equilibrium steady state of the system is reminiscent of a strongly

correlated Tonks-Girardeau gas of impenetrable bosons. Signatures of strong

correlations are identified in the absorption spectrum of the system, as well

as in the intensity correlations of the emitted light. Possible experimental

implementations in state-of-the-art solid-state devices are discussed.

\\ ( http://arxiv.org/abs/0812.4195 , 1229kb)

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arXiv:0812.2701 (*cross-listing*)

Date: Mon, 15 Dec 2008 01:52:38 GMT (1221kb,D)

Title: Electro-Optical Nano-Traps for Neutral Atoms

Authors: Brian Murphy and Lene Vestergaard Hau

Categories: physics.atom-ph cond-mat.mes-hall hep-ph physics.optics quant-ph

Comments: 11 pages, 3 figures

\\

We propose a new class of nanoscale electro-optical traps for neutral atoms.

A prototype is the toroidal trap created by a suspended, charged carbon

nanotube decorated with a silver nanosphere dimer. An illuminating laser field,

blue detuned from an atomic resonance frequency, is strongly focused by

plasmons induced in the dimer and generates both a repulsive potential barrier

near the nanostructure surface and a large viscous damping force that

facilitates trap loading. Atoms with velocities of several meters per second

may be loaded directly into the trap via spontaneous emission of just two

photons.

\\ ( http://arxiv.org/abs/0812.2701 , 1221kb)

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arXiv:0812.3907

Date: Fri, 19 Dec 2008 22:11:34 GMT (1487kb,D)

Title: Microfabricated Chip Traps for Ions

Authors: J. M. Amini, J. Britton, D. Leibfried, D. J. Wineland

Categories: quant-ph

Comments: To be included as a chapter in the forthcoming book "Atom Chips"

edited by J. Reichel and V. Vuletic (to be published by WILEY-VCH)

\\

This submission is an introduction to microfabricated ion traps. We cover the

basics of Paul traps, various geometries for realizing the traps, a number of

design considerations, and, finally, a review of existing microfabricated

traps.

\\ ( http://arxiv.org/abs/0812.3907 , 1487kb)

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arXiv:0812.4048

Date: Sun, 21 Dec 2008 18:14:26 GMT (875kb)

Title: Atomic quantum superposition state generation via optical probing

Authors: Anne E. B. Nielsen, Uffe V. Poulsen, Antonio Negretti, and Klaus

Molmer

Categories: quant-ph

Comments: 10 pages, 9 figures

\\

We analyze the performance of a protocol to prepare an atomic ensemble in a

superposition of two macroscopically distinguishable states. The protocol

relies on conditional measurements performed on a light field, which interacts

with the atoms inside an optical cavity prior to detection, and we investigate

cavity enhanced probing with continuous beams of both coherent and squeezed

light. The stochastic master equations used in the analysis are expressed in

terms of the Hamiltonian of the probed system and the interaction between the

probed system and the probe field and are thus quite generally applicable.

\\ ( http://arxiv.org/abs/0812.4048 , 875kb)

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arXiv:0812.4072

Date: Mon, 22 Dec 2008 00:29:59 GMT (83kb)

Title: Qubit residence time measurements with a Bose-Einstein condensate

Authors: D.Sokolovski

Categories: quant-ph

\\

We show that an electrostatic qubit located near a Bose-Einstein condensate

trapped in a symmetric double-well potential can be used to measure the

duration the qubit has spent in one of its quantum states. The stronq, medium

and weak measurement regimes are analysed and a new type of Zeno effect is

discussed. The analogy between the residence and the traversal (tunnelling)

times is highlighted.

\\ ( http://arxiv.org/abs/0812.4072 , 83kb)

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arXiv:0812.4095

Date: Mon, 22 Dec 2008 05:00:27 GMT (125kb)

Title: The Bounded Anharmonic Oscillators: a simple approach

Authors: F. Maiz and M. Nasr

Categories: quant-ph

Comments: 14 pages

\\

We have developed a simple method to solve anharmonic oscillators equations.

The idea of our method is mainly based on the partitioning of the potential

curve into (n+1) small intervals, solving the Schr\"odinger equation in each

subintervals, and writing the continuity conditions of each solutions at each

subintervals boundary, which leads to the energy quantification condition, so

to the energy levels, and finally, one can calculate the exact wave function

associated to each energy level. Our method has been applied to three examples:

the well-known square well, the bounded and unbounded harmonic oscillators, the

Morse potential, and some anharmonic oscillators bounded by two infinite walls.

Our method is more realistic, simpler, with high degree of accuracy, both

satisfactory and not computationally complicated, and applicable for any forms

of potential. Our results agree very well with the preceding ones.

\\ ( http://arxiv.org/abs/0812.4095 , 125kb)

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arXiv:0812.4077

Date: Mon, 22 Dec 2008 01:27:39 GMT (35kb)

Title: Detection of quantum orders of ultracold atoms in optical lattices by

off-resonant scattering of cavity photons

Authors: Jinwu Ye, Jiangming Zhang, Wuming Liu, Keye Zhang, Yan Li, Zhe-Yu Ou

and Weiping Zhang

Categories: physics.atom-ph physics.optics

\\

We show that cavity enhanced off-resonant light scattering from ultra-cold

atoms loaded on optical lattices can detect the nature of quantum phases such

as the ground state, the excitation spectrum of these quantum phases and also

the universality class of any possible second order quantum phase transitions

between these phases. These quantum phases include not only the well known

superfluid and Mott insulating phases and the superfluid to Mott transition,

but also exotic phases such as charge density wave, valence bond solid and

several kinds of supersolids in one, two and three dimensional optical lattices

and quantum phases transitions between these phases. We also address how the

quantum information encoded in these quantum phases of matter can be

transferred to the light.

\\ ( http://arxiv.org/abs/0812.4077 , 35kb)

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arXiv:0812.4188

Date: Mon, 22 Dec 2008 13:54:46 GMT (499kb,D)

Title: Stark deceleration of lithium hydride molecules

Authors: S. K. Tokunaga, J. M. Dyne, E. A. Hinds and M. R. Tarbutt

Categories: physics.atom-ph

Comments: 14 pages, 6 figures

\\

We describe the production of cold, slow-moving LiH molecules. The molecules

are produced in the ground state using laser ablation and supersonic expansion,

and population is transferred efficiently to the rotationally excited state

using narrowband radiation at the rotational frequency of 444 GHz. The

molecules are then decelerated to low speed using a 100 stage Stark

decelerator. Two different modes of deceleration are demonstrated and compared.

We compare our experimental data to the results of simulations and find good

agreement. These simulations include the velocity dependence of the detection

efficiency and the probability of transitions between the weak-field seeking

and strong-field seeking quantum states. Together, the experimental and

simulated data provide information about the spatial extent of the source of

molecules. We consider the prospects for future trapping and sympathetic

cooling experiments.

\\ ( http://arxiv.org/abs/0812.4188 , 499kb)

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arXiv:0812.4259

Date: Mon, 22 Dec 2008 18:04:04 GMT (173kb)

Title: A simplified optical lattice clock

Authors: N. Poli, M. G. Tarallo, M. Schioppo, C. W. Oates and G. M. Tino

Categories: physics.atom-ph

Comments: 6 pages, 5 figures, submitted to Appl. Phys. B

\\

Existing optical lattice clocks demonstrate a high level of performance, but

they remain complex experimental devices. In order to address a wider range of

applications including those requiring transportable devices, it will be

necessary to simplify the laser systems and reduce the amount of support

hardware. Here we demonstrate two significant steps towards this goal:

demonstration of clock signals from a Sr lattice clock based solely on

semiconductor laser technology, and a method for finding the clock transition

(based on a coincidence in atomic wavelengths) that removes the need for

extensive frequency metrology hardware. Moreover, the unexpected high contrast

in the signal revealed evidence of density dependent collisions in Sr-88 atoms.

\\ ( http://arxiv.org/abs/0812.4259 , 173kb)

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arXiv:0812.4385

Date: Tue, 23 Dec 2008 12:47:11 GMT (41kb)

Title: Universal behavior of a trapped Fermi superfluid in the BCS-unitarity

crossover

Authors: S. K. Adhikari

Categories: cond-mat.other

Comments: 6 pages

\\

From an extensive calculation of static properties of a trapped Fermi

superfluid at zero temperature using a density-functional formulation, we

demonstrate a universal behavior of its observables, such as energy, chemical

potential, radius etc., over the crossover from the BCS limit to unitarity

leading to scaling over many orders of magnitude in fermion number. This

scaling allows to predict the static properties of the system, with a large

number ($\sim 10^5$) of fermions, over the crossover with an error of 1-2%,

from the knowledge of those for a small number ($\sim 10$) of fermions.

\\ ( http://arxiv.org/abs/0812.4385 , 41kb)

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arXiv:0812.4422

Date: Tue, 23 Dec 2008 16:27:37 GMT (196kb,D)

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

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

Categories: cond-mat.str-el

Comments: 11 pages, 5 figs

\\

We study the conditions under which, using a canonical transformation, the

phases sought after for the repulsive Hubbard model, namely a Mott insulator in

the paramagnetic and anti-ferromagnetic phases, and a putative d-wave

superfluid can be deduced from observations in an optical lattice loaded with a

spin-imbalanced ultra-cold Fermi gas with attractive interactions, thus

realizing the attractive Hubbard model. We show that the Mott insulator and

antiferromagnetic phase of the repulsive Hubbard model are in fact more easy to

observe as a paired, and superfluid phase respectively, in the attractive

Hubbard model. The putative d-wave superfluid phase of the repulsive Hubbard

model doped away from half-filling is related to a d-wave antiferromagnetic

phase for the attractive Hubbard model. We discuss the advantages of this

approach to 'quantum simulate' the Hubbard model in an optical lattice over the

approach that attempts to directly simulate the doped Hubbard model in the

repulsive regime. We also point out a number of technical difficulties of the

proposed approach and, in some cases, suggest possible solutions.

\\ ( http://arxiv.org/abs/0812.4422 , 196kb)

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arXiv:0812.4447

Date: Tue, 23 Dec 2008 20:11:07 GMT (102kb)

Title: Non-local pair correlations in the 1D Bose gas at finite temperature

Authors: P. Deuar, A. G. Sykes, D. M. Gangardt, M. J. Davis, P. D. Drummond,

and K. V. Kheruntsyan

Categories: cond-mat.other

Comments: 22 pages, 13 figures

\\

The behavior of the spatial two-particle correlation function is surveyed in

detail for a uniform 1D Bose gas with repulsive contact interactions at finite

temperatures. Both long-, medium-, and short-range effects are investigated.

The results span the entire range of physical regimes, from ideal gas, to

strongly interacting, and from zero temperature to high temperature. We present

perturbative analytic methods, available at strong and weak coupling, and

first-principle numerical results using imaginary time simulations with the

gauge-P representation in regimes where perturbative methods are invalid.

Nontrivial effects are observed from the interplay of thermally induced

bunching behavior versus interaction induced antibunching.

\\ ( http://arxiv.org/abs/0812.4447 , 102kb)

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arXiv:0812.4077

Date: Mon, 22 Dec 2008 01:27:39 GMT (35kb)

Title: Detection of quantum orders of ultracold atoms in optical lattices by

off-resonant scattering of cavity photons

Authors: Jinwu Ye, Jiangming Zhang, Wuming Liu, Keye Zhang, Yan Li, Zhe-Yu Ou

and Weiping Zhang

Categories: physics.atom-ph cond-mat.str-el physics.optics

\\

We show that cavity enhanced off-resonant light scattering from ultra-cold

atoms loaded on optical lattices can detect the nature of quantum phases such

as the ground state, the excitation spectrum of these quantum phases and also

the universality class of any possible second order quantum phase transitions

between these phases. These quantum phases include not only the well known

superfluid and Mott insulating phases and the superfluid to Mott transition,

but also exotic phases such as charge density wave, valence bond solid and

several kinds of supersolids in one, two and three dimensional optical lattices

and quantum phases transitions between these phases. We also address how the

quantum information encoded in these quantum phases of matter can be

transferred to the light.

\\ ( http://arxiv.org/abs/0812.4077 , 35kb)

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\\

arXiv:0812.4381

Date: Tue, 23 Dec 2008 12:24:18 GMT (124kb,D)

Title: Entanglement and the Mott insulator - superfluid phase transition in

bosonic atom chains

Authors: R. J. Costa Farias, M. C. de Oliveira

Categories: quant-ph

Comments: 4 pages, 3 figures

\\

We analyze the developing of bipartite and multipartite entanglement through

the Mott-Insulator - Superfluid quantum phase transition. Starting from a Mott

insulator state, where a filling factor $\nu = N/M = 1$ per lattice site is

considered, we derive an exact expression for a completely connected graph

configuration of bosons and show how bipartite and multipartite entanglement

signals the phase transition predicted in previous works. Moreover, through the

transition bipartite entanglement shows to be monogamous.

\\ ( http://arxiv.org/abs/0812.4381 , 124kb)

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\\

arXiv:0812.4387

Date: Tue, 23 Dec 2008 12:57:47 GMT (368kb,D)

Title: Generalized Purity and Quantum Phase Transition for Bose-Einstein

condensates in a Symmetric Double Well

Authors: Thiago F. Viscondi, K. Furuya, M.C. de Oliveira

Categories: quant-ph

Comments: 4 pages, 4 figures

\\

The generalized purity is employed for investigating the process of coherence

loss and delocalization of the Q-function in the Bloch sphere of a two-mode

Bose-Einstein condensate in a symmetrical double well with cross-collision.

Quantum phase transition of the model is signaled by the generalized purity as

a function of an appropriate parameter of the Hamiltonian and the number of

particles (N). A power law dependence of the critical parameter with N is

derived.

\\ ( http://arxiv.org/abs/0812.4387 , 368kb)

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\\

arXiv:0812.4297

Date: Mon, 22 Dec 2008 21:45:20 GMT (2400kb)

Title: Impact of Electric Fields on Highly Excited Rovibrational States of

Polar Dimers

Authors: Rosario Gonzalez-Ferez and Peter Schmelcher

Categories: physics.atom-ph

Comments: 10 pages, 4 figures

\\

We study the effect of a strong static homogeneous electric field on the

highly excited rovibrational levels of the LiCs dimer in its electronic ground

state. Our full rovibrational investigation of the system includes the

interaction with the field due to the permanent electric dipole moment and the

polarizability of the molecule. We explore the evolution of the states next to

the dissociation threshold as the field strength is increased. The rotational

and vibrational dynamics are influenced by the field; effects such as

orientation, angular motion hybridization and squeezing of the vibrational

motion are demonstrated and analyzed. The field also induces avoided crossings

causing a strong mixing of the electrically dressed rovibrational states.

Importantly, we show how some of these highly excited levels can be shifted to

the continuum as the field strength is increased, and reversely how two atoms

in the continuum can be brought into a bound state by lowering the electric

field strength.

\\ ( http://arxiv.org/abs/0812.4297 , 2400kb)

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\\

arXiv:0812.4335

Date: Tue, 23 Dec 2008 08:22:34 GMT (1315kb)

Title: Direct evaporative cooling of 41K into a Bose-Einstein condensate

Authors: T. Kishimoto, J. Kobayashi, K. Noda, K. Aikawa, M. Ueda, and S. Inouye

Categories: physics.atom-ph

Comments: 4 pages, 4 figures

\\

We have investigated the collisional properties of 41K atoms at ultracold

temperature. To show the possibility to use 41K as a coolant, a Bose-Einstein

condensate of 41K atoms in the stretched state (F=2, m_F=2) was created for the

first time by direct evaporation in a magnetic trap. An upper bound of three

body loss coefficient for atoms in the condensate was determined to be 4(2)

10^{-29} cm -6 s-1. A Feshbach resonance in the F=1, m_F=-1 state was observed

at 51.42(5) G, which is in good agreement with theoretical prediction.

\\ ( http://arxiv.org/abs/0812.4335 , 1315kb)

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\\

arXiv:0812.4355

Date: Tue, 23 Dec 2008 09:23:57 GMT (89kb)

Title: Radio-frequency association of molecules: the dressed state picture

Authors: Q. Beaufils, A. Crubellier, T. Zanon, B. Laburthe-Tolra, E. Marechal,

L. Vernac, O. Gorceix

Categories: physics.atom-ph

Comments: 4 pages, 2 figures

\\

We develop a theoretical model to describe the radio-frequency (rf) induced

coupling of a pair of colliding atoms to a Feshbach molecule when a magnetic

field arbitrarily far from the Feshbach resonance is modulated in time. We use

the dressed atom picture, and show that the coupling strength in presence of rf

is equal to the Feshbach coupling strength multiplied by the square of a Bessel

function. The argument of this function is equal to the ratio of the atomic rf

Rabi frequency to the rf frequency. We experimentally demonstrate this law by

measuring the rate of rf-association of molecules using a Feshbach resonance in

d-wave collisions between ultra-cold chromium atoms.

\\ ( http://arxiv.org/abs/0812.4355 , 89kb)

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\\

arXiv:0812.4425

Date: Tue, 23 Dec 2008 16:36:50 GMT (1881kb)

Title: A large sample study of spin relaxation and magnetometric sensitivity of

paraffin-coated Cs vapor cells

Authors: N. Castagna, G. Bison, G. Di Domenico, A. Hofer, P. Knowles, C.

Macchione, A. Weis

Categories: physics.atom-ph physics.optics

\\

We have manufactured more than 250 nominally identical paraffin-coated Cs

vapor cells (30 mm diameter bulbs) for multi-channel atomic magnetometer

applications. We describe our dedicated cell characterization apparatus. For

each cell we have determined the intrinsic longitudinal, $\sGamma{01}$, and

transverse, $\sGamma{02}$, relaxation rates. Our best cell shows

$\sGamma{01}/2\pi\approx 0.5 Hz, and $\sGamma{02}/2\pi\approx 2 Hz. We find a

strong correlation of both relaxation rates which we explain in terms of

reservoir and spin exchange relaxation. For each cell we have determined the

optimal combination of rf and laser powers which yield the highest sensitivity

to magnetic field changes. Out of all produced cells, 90% are found to have

magnetometric sensitivities in the range of 9 to 30 fTHz. Noise analysis shows

that the magnetometers operated with such cells have a sensitivity close to the

fundamental photon shot noise limit.

\\ ( http://arxiv.org/abs/0812.4425 , 1881kb)

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\\

arXiv:0812.4474

Date: Wed, 24 Dec 2008 02:13:38 GMT (14kb)

Title: Feshbach molecule production in fermionic atomic gases

Authors: V. Gurarie

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

Comments: 4 pages

\\

This paper examines the problem of molecule production in an atomic fermionic

gas close to an s-wave Feshbach resonance by means of a magnetic field sweep

through the resonance. The density of molecules at the end of the process is

derived for narrow resonance and slow sweep.

\\ ( http://arxiv.org/abs/0812.4474 , 14kb)

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\\

arXiv:0812.4530

Date: Wed, 24 Dec 2008 12:52:50 GMT (936kb)

Title: Exploring correlated 1D Bose gases from the superfluid to the

Mott-insulator state by inelastic light scattering

Authors: D. Cl\'ement, N. Fabbri, L. Fallani, C. Fort and M. Inguscio

Categories: cond-mat.other

Comments: 5 pages, 4 figures

\\

We report the Bragg spectroscopy of interacting one-dimensional Bose gases

loaded in optical lattices across the superfluid to Mott-insulator phase

transition. Elementary excitations are created with a non-zero momentum and the

response of the correlated 1D gases is in the linear regime. The complexity of

the strongly correlated quantum phases is directly displayed in the spectra

which exhibit novel features. This work paves the way for a precise

characterization of the state of correlated atomic phases in optical lattices.

\\ ( http://arxiv.org/abs/0812.4530 , 936kb)

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\\

arXiv:0812.4558

Date: Wed, 24 Dec 2008 17:37:25 GMT (824kb)

Title: Effective field theory for spinor dipolar Bose Einstein condensates

Authors: M. Takahashi (Okayama University), Sankalpa Ghosh (I. I. T. Delhi), T.

Mizushima (Okayama University), and K. Machida (Okayama University)

Categories: cond-mat.stat-mech cond-mat.mes-hall

Comments: Latex + 3 eps figures, accepted for publication in a special issue of

EPJB on "Novel Quantum Phases and Mesoscopic Physics in Quantum Gases"

\\

We show that the effective theory of long wavelength low energy behavior of a

dipolar Bose-Einstein condensate(BEC) with large dipole moments (treated as a

classical spin) can be modeled using an extended Non-linear sigma model (NLSM)

like energy functional with an additional non-local term that represents long

ranged anisotropic dipole-dipole interaction. Minimizing this effective energy

functional we calculate the density and spin-profile of the dipolar

Bose-Einstein condensate in the mean-field regime for various trapping

geometries. The resulting configurations show strong intertwining between the

spin and mass density of the condensate, transfer between spin and orbital

angular momentum in the form of Einstein-de Hass effect, and novel topological

properties. We have also described the theoretical framework in which the

collective excitations around these mean field solutions can be studied and

discuss some examples qualitatively.

\\ ( http://arxiv.org/abs/0812.4558 , 824kb)

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The replacements:

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\\

arXiv:0808.0008

replaced with revised version Fri, 19 Dec 2008 11:16:56 GMT (380kb)

Title: Wigner crystal vs. Friedel oscillations in the 1D Hubbard model

Authors: Stefan A. Soeffing, Michael Bortz, Imke Schneider, Alexander Struck,

Michael Fleischhauer and Sebastian Eggert

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

Comments: 5 pages, 4 figures, The most recent version can be found at

http://www.physik.uni-kl.de/eggert/papers/index.html Completely rewritten

version and different title/author list

\\ ( http://arxiv.org/abs/0808.0008 , 380kb)

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\\

arXiv:0808.3823

replaced with revised version Fri, 19 Dec 2008 04:08:04 GMT (247kb)

Title: Formation and Transformation of Vector-Solitons in Two-Species

Bose-Einstein Condensates with Tunable Interaction

Authors: Xunxu Liu, Han Pu, Bo Xiong, W. M. Liu, Jiangbin Gong

Categories: cond-mat.other

Comments: to appear in Physical Review A

\\ ( http://arxiv.org/abs/0808.3823 , 247kb)

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\\

arXiv:0811.2248

replaced with revised version Fri, 19 Dec 2008 11:54:09 GMT (1246kb)

Title: The Fluctuation Theorem and Relaxation to Equilibrium

Authors: Denis J. Evans, Debra J. Searles and Stephen R. Williams

Categories: cond-mat.stat-mech

Comments: 16 pages, no figures

\\ ( http://arxiv.org/abs/0811.2248 , 1246kb)

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\\

arXiv:0806.0270

replaced with revised version Fri, 19 Dec 2008 12:14:10 GMT (1723kb)

Title: The Einstein-Podolsky-Rosen paradox: from concepts to applications

Authors: M. D. Reid, P. D. Drummond, E. G. Cavalcanti, W. P. Bowen, P. K. Lam,

H. A. Bachor, U. L. Andersen, G. Leuchs

Categories: quant-ph

Comments: Colloquium in press in Reviews of Modern Physics, accepted Dec 2008

\\ ( http://arxiv.org/abs/0806.0270 , 1723kb)

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\\

arXiv:0807.1580

replaced with revised version Fri, 19 Dec 2008 14:48:57 GMT (830kb)

Title: Spin squeezing in a bimodal condensate: spatial dynamics and particle

losses

Authors: Yun Li (LKB - Lhomond, ECNU), Philipp Treutlein, Jakob Reichel (LKB -

Lhomond), Alice Sinatra (LKB - Lhomond)

Categories: quant-ph

Comments: 18 pages, 13 figures. Accepted for publication in European Physical

Journal B

\\ ( http://arxiv.org/abs/0807.1580 , 830kb)

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\\

arXiv:0809.2145

replaced with revised version Mon, 22 Dec 2008 05:31:22 GMT (653kb)

Title: Bragg spectroscopy of a strongly interacting Fermi gas

Authors: G. Veeravalli, E. Kuhnle, P. Dyke, and C. J. Vale

Categories: cond-mat.other

Comments: Replaced with published version

Journal-ref: Phys. Rev. Lett. 101, 250403 (2008)

DOI: 10.1103/PhysRevLett.101.250403

\\ ( http://arxiv.org/abs/0809.2145 , 653kb)

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\\

arXiv:0810.0360

replaced with revised version Mon, 22 Dec 2008 07:13:30 GMT (70kb)

Title: Semilinear response for the heating rate of cold atoms in vibrating

traps

Authors: A. Stotland, D. Cohen, N. Davidson

Categories: quant-ph cond-mat.mes-hall

Comments: 7 pages, 6 figures, improved version

\\ ( http://arxiv.org/abs/0810.0360 , 70kb)

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\\

arXiv:0812.1581

replaced with revised version Sat, 20 Dec 2008 20:03:38 GMT (1999kb)

Title: Superconductivity close to the Mott state: From condensed-matter systems

to superfluidity in optical lattices

Authors: Karyn Le Hur and T. Maurice Rice

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

Comments: 97 pages and 18 figures

\\ ( http://arxiv.org/abs/0812.1581 , 1999kb)

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\\

arXiv:0708.0092

replaced with revised version Tue, 23 Dec 2008 21:14:27 GMT (371kb)

Title: Fluctuations of a weakly interacting Bose-Einstein condensate

Authors: Z. Idziaszek, L. Zawitkowski, M. Gajda, K. Rzazewski

Categories: cond-mat.stat-mech

Comments: 4 pages, 4 figures; vastly improved version, now includes thermal

atom interactions for the condensate statistics

\\ ( http://arxiv.org/abs/0708.0092 , 371kb)

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Till next time,

Matt.

-- ========================================================================= Dr M. J. Davis, Associate Professor in Physics School of Mathematics and Physics, ph : +61 7 334 69824 The University of Queensland, fax : +61 7 336 51242 Brisbane, QLD 4072, mdavis_at_physics.uq.edu.au Australia. www.physics.uq.edu.au/people/mdavis/ ========================================================================= Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/ ========================================================================= Legal stuff: Unless stated otherwise, this e-mail represents only the views of the sender and not the views of the University of Queensland =========================================================================Received on Wed Feb 25 2009 - 08:31:33 EST

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