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

Date: Fri, 21 Aug 2009 13:51:58 +1000

Date: Fri, 21 Aug 2009 13:51:58 +1000

Dear subscribers,

Things have fallen behind again, but I am hoping my team of helpers will have us

up to date again soon. This week's list was compiled by Dr Andy Ferris (who

deserves congratulations for officially receiving his PhD just this week!)

This week there are 31 new preprints and 10 replacements:

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arXiv:0906.3528

Date: Thu, 18 Jun 2009 20:44:16 GMT (147kb)

Title: Haldane charge conjecture in one-dimensional multicomponent fermionic

cold atoms

Authors: H. Nonne, P. Lecheminant, S. Capponi, G. Roux, E. Boulat

Categories: cond-mat.str-el cond-mat.quant-gas

Comments: 4 pages, 4 figures

\\

A Haldane conjecture is revealed for spin-singlet charge modes in

2N-component fermionic cold atoms loaded into one-dimensional optical lattice.

By means of a low-energy approach and DMRG calculations, we show the emergence

of gapless and gapped phases depending on the parity of N for attractive

interactions at half-filling. In particular, the analogue of the Haldane phase

of the spin-1 Heisenberg chain is stabilized for N = 2 with non-local string

charge correlation, and pseudo-spin 1/2 edge states. At the heart of this

even-odd behavior is the existence of spin-singlet pseudo-spin N/2 operator

which governs the low-energy properties of the model for attractive

interactions and give rise to the Haldane physics.

\\ ( http://arxiv.org/abs/0906.3528 , 147kb)

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arXiv:0906.3564

Date: Fri, 19 Jun 2009 03:21:01 GMT (1212kb)

Title: Vortices in $p$-Wave Superfluids of Trapped Fermionic Atom Gases

Authors: Y. Tsutsumi, K. Machida

Categories: cond-mat.supr-con cond-mat.quant-gas

Comments: 17 pages, 9 figures, to be published in J. Phys. Soc. Jpn

\\

In order to help detecting superfluidity, we theoretically investigate p-wave

pairing superfluids in neutral Fermion atom gases confined by a three

dimensimentional (3D) harmonic potential. The Ginzburg-Landau framework, which

is generic for p-wave superfluids, is used to describe the order parameter

spatial structure, or texture characterized by the $l$-vector both at rest and

under rotation. The $l$-vector configuration is strongly contrained by the

boundary condition due to a trap. It is found that the ground state textures

exhibit spontaneous supercurrent at rest both cigar and pancake shape traps.

The current direction depends on the trapping shape. Under rotation a pair of

half-quantum vortex with half-winding number enters a system and is stabilized

for both trap geometries. We give detailed explanation for their 3D structure.

The deformations of the condensate shape are seen with increasing the rotation

speed, which is tightly connected with the underlying vortex formation where

the condensates are depressed in the vortex core.

\\ ( http://arxiv.org/abs/0906.3564 , 1212kb)

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arXiv:0906.3687

Date: Fri, 19 Jun 2009 14:52:48 GMT (2291kb)

Title: Controlled localization of interacting bosons in a disordered optical

lattice

Authors: J. Santos, R. A. Molina, J. Ortigoso and M. Rodriguez

Categories: cond-mat.quant-gas

Comments: 5 pages 6 figs

\\

We show how a fast oscillatory force can be used to control the localization

properties of interacting bosons trapped in a disordered optical lattice. By

adiabatically increasing the amplitude of the external driving force one can

induce a transition from superfluid to insulating states such as a Bose-Glass

or a Mott-insulator or, for strong disorder, from an Anderson-Glass to a

Bose-Glass. Within the disordered Bose-Hubbard model, we show that this method

can be used to explore in a controlled way the entire phase diagram of bosons

in the presence of disorder and interactions.

\\ ( http://arxiv.org/abs/0906.3687 , 2291kb)

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arXiv:0906.3511

Date: Thu, 18 Jun 2009 20:37:05 GMT (475kb)

Title: Experimental quantum-enhanced estimation of a lossy phase shift

Authors: M. Kacprowicz, R. Demkowicz-Dobrzanski, W. Wasilewski, K. Banaszek, I.

A. Walmsley

Categories: quant-ph

Comments: 5 pages

\\

When standard light sources are employed, the precision of the phase

determination is limited by the shot noise. Quantum entanglement provides means

to exceed this limit with the celebrated example of N00N states that saturate

the ultimate Heisenberg limit on precision, but at the same time are extremely

fragile to losses. In contrast, we provide experimental evidence that

appropriately engineered quantum states outperform both standard and N00N

states in the precision of phase estimation when losses are present.

\\ ( http://arxiv.org/abs/0906.3511 , 475kb)

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arXiv:0906.3664

Date: Fri, 19 Jun 2009 13:30:37 GMT (1363kb)

Title: One-Dimensional Optical Lattice Clock with a Fermionic 171Yb Isotope

Authors: Takuya Kohno, Masami Yasuda, Kazumoto Hosaka, Hajime Inaba, Yoshiaki

Nakajima, Feng-Lei Hong

Categories: physics.atom-ph physics.optics

Comments: 11 pages, 5 figures, Appl. Phys. Express (Open Select Paper: open

access)

Journal-ref: Appl. Phys. Express 2 (2009) 072501

DOI: 10.1143/APEX.2.072501

\\

We demonstrate a one-dimensional optical lattice clock with ultracold 171Yb

atoms, which is free from the linear Zeeman effect. The absolute frequency of

the 1S0(F = 1/2) - 3P0(F = 1/2) clock transition in 171Yb is determined to be

518 295 836 590 864(28) Hz with respect to the SI second.

\\ ( http://arxiv.org/abs/0906.3664 , 1363kb)

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arXiv:0906.3753

Date: Mon, 22 Jun 2009 00:10:32 GMT (384kb,P)

Title: Zero Sound in Dipolar Fermi Gases

Authors: Shai Ronen and John Bohn

Categories: cond-mat.quant-gas

\\

We study the propagation of sound in a homogeneous dipolar gas at zero

temperature, known as zero sound. We find that below a critical dipolar

interaction, undamped sound propagation is possible only in a range of solid

angles around the direction of polarization of the dipoles. For larger

interaction strength, zero sound propagates in all directions, but its nature

changes as a function of direction. In particular, there appears a transverse

mode for the perpendicular propagation direction, which resembles the

transverse mode in liquid He-3. We explain how these properties arise as a

result of the anisotropic dipolar interaction.

\\ ( http://arxiv.org/abs/0906.3753 , 384kb)

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arXiv:0906.3777

Date: Sat, 20 Jun 2009 04:06:09 GMT (5kb)

Title: Do bosons obey Bose-Einstein distribution: two iterated limits of

Gentile distribution

Authors: Wu-Sheng Dai and Mi Xie

Categories: cond-mat.stat-mech

Comments: 6 pages, no figure

Journal-ref: Physics Letters A 373 (2009) 1524

\\

It is a common impression that by only setting the maximum occupation number

to infinity, which is the demand of the indistinguishability of bosons, one can

achieve the statistical distribution that bosons obey -- the Bose-Einstein

distribution. In this letter, however, we show that only with an infinite

maximum occupation number one cannot uniquely achieve the Bose-Einstein

distribution, since in the derivation of the Bose-Einstein distribution, the

problem of iterated limit is encountered. For achieving the Bose-Einstein

distribution, one needs to take both the maximum occupation number and the

total number of particles to infinities, and, then, the problem of the order of

taking limits arises. Different orders of the limit operations will lead to

different statistical distributions. For achieving the Bose-Einstein

distribution, besides setting the maximum occupation number, we also need to

state the order of the limit operations.

\\ ( http://arxiv.org/abs/0906.3777 , 5kb)

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arXiv:0906.3905

Date: Mon, 22 Jun 2009 02:03:51 GMT (13kb)

Title: Numerical representation of quantum states in the positive-P and Wigner

representations

Authors: M. K. Olsen and A. S. Bradley

Categories: cond-mat.quant-gas

Comments: 16 pages, single column format

\\

Numerical stochastic integration is a powerful tool for the investigation of

quantum dynamics in interacting many body systems. As with all numerical

integration of differential equations, the initial conditions of the system

being investigated must be specified. With application to quantum optics in

mind, we show how various commonly considered quantum states can be numerically

simulated by the use of widely available Gaussian and uniform random number

generators. We note that the same methods can also be applied to computational

studies of Bose-Einstein condensates, and give some examples of how this can be

done.

\\ ( http://arxiv.org/abs/0906.3905 , 13kb)

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arXiv:0906.3976

Date: Mon, 22 Jun 2009 11:09:01 GMT (268kb)

Title: Adiabatic Splitting, Transport, and Self-Trapping of a Bose-Einstein

Condensate in a Double-Well Potential

Authors: C. Ottaviani, V. Ahufinger, R. Corbal\'an, and J. Mompart

Categories: cond-mat.quant-gas

Comments: 8 pages and 7 figures

\\

We show that the adiabatic dynamics of a Bose-Einstein condensate (BEC) in a

double well potential can be described in terms of a dark variable resulting

from the combination of the population imbalance and the spatial atomic

coherence between the two wells. By means of this dark variable, we extend, to

the non-linear matter wave case, the recent proposal by Vitanov and Shore

[Phys. Rev. A 73, 053402 (2006)] on adiabatic passage techniques to coherently

control the population of two internal levels of an atom/molecule. We

investigate the conditions to adiabatically split or transport a BEC as well as

to prepare an adiabatic self trapping state by the optimal delayed temporal

variation of the tunneling rate via either the energy bias between the two

wells or the BEC non-linearity. The emergence of non-linear eigenstates and

unstable stationary solutions of the system as well as their role in the

breaking down of the adiabatic dynamics is investigated in detail.

\\ ( http://arxiv.org/abs/0906.3976 , 268kb)

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arXiv:0906.3983

Date: Mon, 22 Jun 2009 11:30:57 GMT (46kb)

Title: Pseudogap in fermionic density of states in the BCS-BEC crossover of

atomic Fermi gases

Authors: S. Tsuchiya, R. Watanabe, and Y. Ohashi

Categories: cond-mat.quant-gas

Comments: 6 pages, 4 figures, Proceedings of QFS 2009

\\

We study pseudogap behaviors of ultracold Fermi gases in the BCS-BEC

crossover region. We calculate the density of states (DOS), as well as the

single-particle spectral weight, above the superfluid transition temperature

$T_{\rm c}$ including pairing fluctuations within a $T$-matrix approximation.

We find that DOS exhibits a pseudogap structure in the BCS-BEC crossover

region, which is most remarkable near the unitarity limit. We determine the

pseudogap temperature $T^*$ at which the pseudogap structure in DOS disappears.

We also introduce another temperature $T^{**}$ at which the BCS-like

double-peak structure disappears in the spectral weight. While one finds

$T^*>T^{**}$ in the BCS regime, $T^{**}$ becomes higher than $T^*$ in the

crossover and BEC regime. We also determine the pseudogap region in the phase

diagram in terms of temperature and pairing interaction.

\\ ( http://arxiv.org/abs/0906.3983 , 46kb)

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arXiv:0906.3995

Date: Mon, 22 Jun 2009 13:05:09 GMT (90kb)

Title: Transport in a Luttinger liquid with dissipation: two impurities

Authors: Leiming Chen, Zoran Ristivojevic, and Thomas Nattermann

Categories: cond-mat.str-el cond-mat.dis-nn

Comments: 11 pages, 3 figures

\\

We consider theoretically the transport in a one-channel spinless Luttinger

liquid with two strong impurities in the presence of dissipation. As a

difference with respect to the dissipation free case, where the two impurities

fully transmit electrons at resonance points, the dissipation prevents complete

transmission in the present situation. A rich crossover diagram for the

conductance as a function of applied voltage, temperature, dissipation

strength, Luttinger liquid parameter K and the deviation from the resonance

condition is obtained. For weak dissipation and 1/2<K<1, the conduction shows a

non-monotonic increase as a function of temperature or voltage. For strong

dissipation the conduction increases monotonically but is exponentially small.

\\ ( http://arxiv.org/abs/0906.3995 , 90kb)

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arXiv:0902.4623 (*cross-listing*)

Date: Thu, 26 Feb 2009 16:27:00 GMT (8kb)

Date (revised v2): Mon, 9 Mar 2009 18:51:47 GMT (24kb)

Date (revised v3): Mon, 22 Jun 2009 08:44:56 GMT (24kb)

Title: Fidelity susceptibility and quantum adiabatic condition in thermodynamic

limits

Authors: Shi-Jian Gu

Categories: quant-ph cond-mat.str-el

Comments: 4 pages, final version accepted by PRE

\\

In this work, we examine the validity of quantum adiabatic theorem in

thermodynamic systems. For a $d$-dimensional quantum many-body system, we show

that the duration time $\tau_0$ required by its ground-state adiabatic process

does not depend on the microscopic details, but the scaling dimension of the

fidelity susceptibility $d_a$. Our result, therefore, provides a quantitative

time scale of the quantum adiabatic theorem in thermodynamic systems. The

quantum adiabatic theorem might be violated in case that the scaling dimension

of the fidelity susceptibility is larger than the system's real dimension

($d_a>d$).

\\ ( http://arxiv.org/abs/0902.4623 , 24kb)

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arXiv:0906.3779

Date: Mon, 22 Jun 2009 16:04:10 GMT (1962kb)

Title: Atom-ion quantum gate

Authors: Hauke Doerk-Bendig, Zbigniew Idziaszek and Tommaso Calarco

Categories: quant-ph

Comments: submitted to Phys. Rev. A

\\

We study ultracold collisions of ions with neutral atoms in traps. Recently,

ultracold atom-ion systems are becoming available in experimental setups, where

their quantum states can be coherently controlled. This allows for an

implementation of quantum information processing combining the advantages of

charged and neutral particles. The state-dependent dynamics that is a necessary

ingredient for quantum computation schemes is provided in this case by the

short-range interaction forces depending on hyperfine states of both particles.

In this work we develop a theoretical description of spin-state-dependent

trapped atom-ion collisions in the framework of a Multichannel Quantum Defect

Theory (MQDT) and formulate an effective single channel model that reduces the

complexity of the problem.

Based on this description we simulate a two-qubit phase gate between a Ba135+

ion and a Rb87 atom using a realistic combination of the singlet and triplet

scattering lengths. We optimize and accelerate the gate process with the help

of optimal control techniques. Our result is a gate fidelity 0.999 within 350

microseconds.

\\ ( http://arxiv.org/abs/0906.3779 , 1962kb)

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arXiv:0906.3938

Date: Mon, 22 Jun 2009 07:29:43 GMT (79kb)

Title: On coherence lengths of wave packets I

Authors: Kenzo Ishikawa and Yutaka Tobita

Categories: quant-ph

Comments: 27 pages,3 figures

Report-no: EPHOU-09-002

\\

Coherence lengths of one particle states described by quantum wave functions

are studied. We show that one particle states in various situations are not

described by simple plane waves but are described by wave packets that are

superpositions of plane waves. Wave packet is an approximate eigenstate of the

free Hamiltonian and has a finite spatial size which we call the coherence

length. The coherence lengths in the coordinate space and in the momentum space

are studied in the present paper. We investigate several mechanisms of forming

wave packets, stabilities of wave packets, and transformations of wave packets.

\\ ( http://arxiv.org/abs/0906.3938 , 79kb)

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arXiv:0906.4259

Date: Tue, 23 Jun 2009 13:42:39 GMT (220kb)

Title: Vortices in dipolar condensates with dominant dipolar interactions

Authors: M. Abad, M. Guilleumas, R. Mayol, M. Pi, and D. M. Jezek

Categories: cond-mat.quant-gas

Comments: 10 pages with 9 figures

Journal-ref: Phys. Rev. A 79, 063622 (2009)

DOI: 10.1103/PhysRevA.79.063622

\\

We present full three-dimensional numerical calculations of single vortex

states in rotating dipolar condensates. We consider a Bose-Einstein condensate

of 52Cr atoms with dipole-dipole and s-wave contact interactions confined in an

axially symmetric harmonic trap. We obtain the vortex states by numerically

solving the Gross-Pitaevskii equation in the rotating frame with no further

approximations. We investigate the properties of a single vortex and calculate

the critical angular velocity for different values of the s-wave scattering

length. We show that, whereas the standard variational approach breaks down in

the limit of pure dipolar interactions, exact solutions of the Gross-Pitaevskii

equation can be obtained for values of the s-wave scattering length down to

zero. The energy barrier for the nucleation of a vortex is calculated as a

function of the vortex displacement from the rotation axis for different values

of the angular velocity of the rotating trap.

\\ ( http://arxiv.org/abs/0906.4259 , 220kb)

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arXiv:0906.4300

Date: Tue, 23 Jun 2009 16:28:31 GMT (15kb)

Title: BCS-BEC crossover with unequal mass fermions

Authors: Roberto B. Diener and Mohit Randeria

Categories: cond-mat.quant-gas

Comments: 4 pages, 3 figures

\\

We investigate the crossover from BCS pairing to molecular BEC in an atomic

gas with two fermion species with masses $m_\up \ne m_\dn$ tuned through a

Feshbach resonance. We present results for the T=0 equation of state as a

function of the scattering length including the effects of Gaussian

fluctuations about the mean field ground state. We compute the ground state

energy as a function of $m_\up/m_\dn$ at unitarity and find excellent agreement

with the quantum Monte Carlo result for $m_\up/m_\dn = 6.67$ for a

$^{40}$K-$^6$Li mixture. We show that the dimer scattering length in the BEC

limit as a function of $m_\up/m_\dn$ compares well with exact four-body results

of Petrov {\it et al}. We also derive the condition for trapping frequencies to

obtain an unpolarized gas in a harmonic trap.

\\ ( http://arxiv.org/abs/0906.4300 , 15kb)

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arXiv:0906.4143

Date: Mon, 22 Jun 2009 23:16:11 GMT (355kb)

Title: Dynamics of a bistable Mott insulator to superfluid phase transition in

cavity optomechanics

Authors: K. Zhang, W. Chen, P. Meystre

Categories: quant-ph

Comments: 6 pages, 5 figures

\\

We study the dynamics of the many-body state of ultracold bosons trapped in a

bistable optical lattice in an optomechanical resonator controlled by a

time-dependent input field. We focus on the dynamics of the many-body system

following discontinuous jumps of the intracavity field. We identify

experimentally realizable parameters for the bistable quantum phase transition

between Mott insulator and superfluid.

\\ ( http://arxiv.org/abs/0906.4143 , 355kb)

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arXiv:0906.4158

Date: Tue, 23 Jun 2009 03:02:17 GMT (892kb)

Title: Ultracold Fermions in a Graphene-Type Optical Lattice

Authors: Kean Loon Lee, Benoit Gremaud, Rui Han, Berthold-Georg Englert and

Christian Miniatura

Categories: quant-ph

\\

Some important features of the graphene physics can be reproduced by loading

ultracold fermionic atoms in a two-dimensional optical lattice with honeycomb

symmetry and we address here its experimental feasibility. We analyze in great

details the optical lattice generated by the coherent superposition of three

coplanar running laser waves with respective angles $2\pi/3$. The corresponding

band structure displays Dirac cones located at the corners of the Brillouin

zone and close to half-filling this system is well described by massless Dirac

fermions. We characterize their properties by accurately deriving the

nearest-neighbor hopping parameter $t_0$ as a function of the optical lattice

parameters. Our semi-classical instanton method proves in excellent agreement

with an exact numerical diagonalization of the full Hamilton operator in the

tight-binding regime. We conclude that the temperature range needed to access

the Dirac fermions regime is within experimental reach. We also analyze

imperfections in the laser configuration as they lead to optical lattice

distortions which affect the Dirac fermions. We show that the Dirac cones do

survive up to some critical intensity or angle mismatches which are easily

controlled in actual experiments. In the tight-binding regime, we predict, and

numerically confirm, that these critical mismatches are inversely proportional

to the square-root of the optical potential strength. We also briefly discuss

the interesting possibility of fine-tuning the mass of the Dirac fermions by

controlling the laser phase in an optical lattice generated by the incoherent

superposition of three coplanar independent standing waves with respective

angles $2\pi/3$.

\\ ( http://arxiv.org/abs/0906.4158 , 892kb)

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arXiv:0906.4378

Date: Tue, 23 Jun 2009 23:45:30 GMT (204kb,D)

Title: A Universal Trimer in a Three-Component Fermi Gas

Authors: A. N. Wenz, T. Lompe, T. B. Ottenstein, F. Serwane, G. Z\"urn, and S.

Jochim

Categories: cond-mat.quant-gas

Comments: 5 pages, 3 figures

\\

We show that the recently measured magnetic field dependence of three-body

loss in a three-component mixture of ultracold $^6$Li atoms [1,2] can be

explained by the presence of a universal trimer state. Previous work suggested

a universal trimer state as a probable explanation, yet failed to get good

agreement between theory and experiment over the whole range of magnetic

fields. For our description we adapt the theory of Braaten and Hammer [3] for

three identical bosons to the case of three distinguishable fermions by

combining the three scattering lengths $a_{12},$ $a_{23}$ and $a_{13}$ between

the three components to an effective interaction parameter $a_m$. We show that

taking into account a magnetic field variation of the lifetime of the trimer

state is essential to obtain a complete understanding of the observed decay

rates.

\\ ( http://arxiv.org/abs/0906.4378 , 204kb)

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arXiv:0906.4455

Date: Wed, 24 Jun 2009 12:00:52 GMT (63kb)

Title: Feynman path-integral treatment of the BEC-impurity polaron

Authors: J. Tempere, W. Casteels, M.K. Oberthaler, E. Timmermans, J.T. Devreese

Categories: cond-mat.quant-gas

Comments: 13 pages, 3 figures

\\

The description of an impurity atom in a Bose-Einstein condensate can be cast

in the form of Frohlich's polaron Hamiltonian, where the Bogoliubov excitations

play the role of the phonons. An expression for the corresponding polaronic

coupling strength is derived, relating the coupling strength to the scattering

lengths, the trap size and the number of Bose condensed atoms. This allows to

identify several approaches to reach the strong-coupling limit for the quantum

gas polarons, whereas this limit was hitherto experimentally inaccessible in

solids. We apply Feynman's path-integral method to calculate for all coupling

strengths the polaronic shift in the free energy and the increase in the

effective mass. The effect of temperature on these quantities is included in

the description. We find similarities to the acoustic polaron results and

indications of a transition between free polarons and self-trapped polarons.

The prospects, based on the current theory, of investigating the polaron

physics with ultracold gases are discussed for lithium atoms in a sodium

condensate.

\\ ( http://arxiv.org/abs/0906.4455 , 63kb)

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arXiv:0906.4319 (*cross-listing*)

Date: Tue, 23 Jun 2009 17:20:00 GMT (17kb)

Title: Microscopic description of the chiral Tomonaga-Luttinger liquid at the

fractional quantum Hall edge

Authors: Wei Huang, Zhao-Long Wang, Mu-Lin Yan

Categories: hep-th cond-mat.mes-hall cond-mat.str-el

Comments: 14 pages, 2 figures

Report-no: USTC-ICTS-09-08

\\

The effective field theory of the fractional quantum Hall edge is

reformulated from microscopic dynamics. Noncommutative Chern-Simons theory is a

microscopic description for the quantum Hall fluid. We use it for reference.

Considering relabeling symmetry of the electrons and incompressibility of the

fluid, we obtain a constraint and derive a chiral Tomonaga-Luttinger liquid

theory containing interaction terms. We calculate one-loop corrections to the

phonon and electron propagators and get a new tunneling exponent. It agrees

with experiments.

\\ ( http://arxiv.org/abs/0906.4319 , 17kb)

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arXiv:0906.4417

Date: Wed, 24 Jun 2009 07:34:34 GMT (838kb)

Title: Population Dynamics in Cold Gases Resulting from the Long-Range

Dipole-Dipole Interaction

Authors: A. Mandilara, V. M. Akulin and P. Pillet

Categories: quant-ph

Comments: 6 pages, 8 figures

\\

We consider the effect of the long range dipole-dipole interaction on the

excitation exchange dynamics of cold two-level atomic gase in the conditions

where the size of the atomic cloud is large as compared to the wavelength of

the dipole transition. We show that this interaction results in population

redistribution across the atomic cloud and in specific spectra of the

spontaneous photons emitted at different angles with respect to the direction

of atomic polarization.

\\ ( http://arxiv.org/abs/0906.4417 , 838kb)

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arXiv:0906.4606

Date: Thu, 25 Jun 2009 05:35:39 GMT (683kb)

Title: Finite temperature theory of bosons in optical lattices

Authors: D. Baillie and P. B. Blakie

Categories: cond-mat.quant-gas

Comments: 24 pages, 21 figures

\\

A practical finite temperature theory is developed for the superfluid regime

of a weakly interacting Bose gas in an optical lattice with additional harmonic

confinement. We derive an extended Bose-Hubbard model that is valid for shallow

lattices and when excited bands are occupied. Using the

Hartree-Fock-Bogoliubov-Popov mean-field approach, and applying local density

and coarse-grained envelope approximations, we arrive at a theory that can be

numerically implemented accurately and efficiently. We present results for a

three-dimensional system, characterizing the importance of the features of the

extended Bose-Hubbard model and compare against other theoretical results and

show improved agreement with experimental data. We present extensive analysis

of the microscopic parameters in our extended Bose-Hubbard model, exploring the

validity of commonly used approximations.

\\ ( http://arxiv.org/abs/0906.4606 , 683kb)

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arXiv:0906.4593

Date: Thu, 25 Jun 2009 02:33:49 GMT (285kb)

Title: Ground State of Fermions in a ID Trap with $\delta$ Function Interaction

Authors: C. N. Yang

Categories: cond-mat.str-el

Comments: 7 pages, 1 figure

\\

The ground state of Fermions in a ID trap with $\delta$ function interaction

is studied mathematically with group theory ideas.

\\ ( http://arxiv.org/abs/0906.4593 , 285kb)

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arXiv:0906.4584

Date: Thu, 25 Jun 2009 00:08:13 GMT (222kb)

Title: Phases of a bilayer Fermi gas

Authors: Yusuke Nishida

Categories: cond-mat.quant-gas

Comments: 4 pages, 5 figures

Report-no: MIT-CTP 4048

\\

We investigate a two-species Fermi gas in which one species is confined in

two parallel layers and interacts with the other species in the

three-dimensional space by a tunable short-range interaction. Based on the

controlled weak coupling analysis and the exact three-body calculation, we show

that the system has a rich phase diagram in the plane of the effective

scattering length and the layer separation. Resulting phases include an

interlayer s-wave pairing, an intralayer p-wave pairing, a dimer Bose-Einstein

condensation, and a Fermi gas of Efimov-like trimers. Our system provides a

widely applicable scheme to induce long-range interlayer correlations in

ultracold atoms.

\\ ( http://arxiv.org/abs/0906.4584 , 222kb)

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arXiv:0906.4708

Date: Thu, 25 Jun 2009 15:01:04 GMT (1152kb)

Title: Spatial Dependence of Entropy in Trapped Ultracold Bose Gases

Authors: Lincoln D. Carr and Markus K. Oberthaler

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

Comments: 5 pages, 4 figures

\\

We find a new physical regime in the trapped Bose-Hubbard Hamiltonian using

time-evolving block decimation. Between Mott-insulating and superfluid phases,

the latter induced by trap compression, a spatially self-organized state

appears in which non-local entropy signals entanglement between spatially

distant superfluid shells. We suggest a linear rather than harmonic potential

as an ideal way to observe such a self-organized system. We also explore both

quantum information and thermal entropies in the superfluid regime, finding

that while the former follows the density closely the latter can be strongly

manipulated with the mean field.

\\ ( http://arxiv.org/abs/0906.4708 , 1152kb)

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arXiv:0906.4731

Date: Thu, 25 Jun 2009 16:05:45 GMT (52kb)

Title: Observation of universality in ultracold 7Li three-body recombination

Authors: Noam Gross, Zav Shotan, Servaas Kokkelmans and Lev Khaykovich

Categories: cond-mat.other

Comments: 5 pages, 2 figures

\\

We report on experimental evidence of universality in ultracold 7Li atoms'

three-body recombination loss in the vicinity of a Feshbach resonance. We

observe a recombination minimum and an Efimov resonance in regions of positive

and negative scattering lengths, respectively, which are connected through the

pole of the Feshbach resonance. Both observed features lie deeply within the

range of validity of the universal theory and we find that the relations

between their properties, i.e. widths and locations, are in an excellent

agreement with the theoretical predictions.

\\ ( http://arxiv.org/abs/0906.4731 , 52kb)

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arXiv:0906.4732

Date: Thu, 25 Jun 2009 16:07:58 GMT (35kb)

Title: Mixtures of correlated bosons and fermions: Dynamical mean-field theory

for normal and condensed phases

Authors: Krzysztof Byczuk and Dieter Vollhardt

Categories: cond-mat.quant-gas cond-mat.str-el

Comments: 11 pages

\\

We derive a dynamical mean-field theory for mixtures of interacting bosons

and fermions on a lattice (BF-DMFT). The BF-DMFT is a comprehensive,

thermodynamically consistent framework for the theoretical investigation of

Bose-Fermi mixtures and is applicable for arbitrary values of the coupling

parameters and temperatures. It becomes exact in the limit of high spatial

dimensions $d$ or coordination number $Z$ of the lattice. In particular, the

BF-DMFT treats normal and condensed bosons on equal footing and thus includes

the effects caused by their dynamic coupling. Using the BF-DMFT we investigate

two different interaction models of correlated lattice bosons and fermions, one

where all particles are spinless (model I) and one where fermions carry a spin

one-half (model II). In model I the local, repulsive interaction between bosons

and fermions can give rise to an attractive effective interaction between the

bosons. In model II it can also lead to an attraction between the fermions.

\\ ( http://arxiv.org/abs/0906.4732 , 35kb)

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arXiv:0906.4512 (*cross-listing*)

Date: Wed, 24 Jun 2009 16:12:24 GMT (32kb)

Title: Bethe equations for generalized Hubbard models

Authors: V. Fomin, L. Frappat and E. Ragoucy

Categories: hep-th cond-mat.str-el math-ph math.MP

Comments: 36 pages

Report-no: LAPTH-1334/09

\\

We compute the eigenfunctions, energies and Bethe equations for a class of

generalized integrable Hubbard models based on gl(n|m)\oplus gl(2)

superalgebras. The Bethe equations appear to be similar to the Hubbard model

ones, up to a phase due to the integration of a subset of `simple' Bethe

equations. We discuss relations with AdS/CFT correspondence, and with condensed

matter physics.

\\ ( http://arxiv.org/abs/0906.4512 , 32kb)

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arXiv:0906.4726

Date: Thu, 25 Jun 2009 16:00:22 GMT (1202kb)

Title: Ultra-cold mechanical resonators coupled to atoms in an optical lattice

Authors: Andrew A. Geraci, John Kitching

Categories: quant-ph

Comments: 5 pages, 3 figures

\\

We propose an experiment utilizing an array of cooled micro-cantilevers

coupled to a sample of ultra-cold atoms trapped near a micro-fabricated

surface. The cantilevers allow individual lattice site addressing for atomic

state control and readout, and potentially may be useful in optical lattice

quantum computation schemes. Assuming resonators can be cooled to their

vibrational ground state, the implementation of a two-qubit controlled-NOT gate

with atomic internal states and the motional states of the resonator is

described. We also consider a protocol for entangling two or more cantilevers

on the atom chip with different resonance frequencies, using the trapped atoms

as an intermediary. Although similar experiments could be carried out with

magnetic microchip traps, the optical confinement scheme we consider may

exhibit reduced near-field magnetic noise and decoherence. Prospects for using

this novel system for tests of quantum mechanics at macroscopic scales or

quantum information processing are discussed.

\\ ( http://arxiv.org/abs/0906.4726 , 1202kb)

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arXiv:0906.4724

Date: Thu, 25 Jun 2009 15:55:52 GMT (221kb)

Title: Measurement and simulation of laser-induced fluorescence from

non-equilibrium ultracold neutral plasmas

Authors: A. Denning, S. D. Bergeson, and F. Robicheaux

Categories: physics.atom-ph physics.plasm-ph

\\

We report new measurements and simulations of laser-induced fluorescence in

ultracold neutral plasmas. We focus on the earliest times, when the plasma

equilibrium is evolving and before the plasma expands. In the simulation, the

ions interact via the Yukawa potential in a small cell with wrapped boundary

conditions. We solve the optical Bloch equation for each ion in the simulation

as a function of time. Both the simulation and experiment show the initial

Bloch vector rotation, disorder-induced heating, and coherent oscillation of

the rms ion velocity. Detailed modeling of the fluorescence signal makes it

possible to use fluorescence spectroscopy to probe ion dynamics in ultracold

and strongly coupled plasmas.

\\ ( http://arxiv.org/abs/0906.4724 , 221kb)

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The replacements:

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arXiv:0902.0388

replaced with revised version Mon, 22 Jun 2009 10:46:15 GMT (215kb)

Title: Dispersive spectrum and orbital order of spinless p-band fermions in an

optical lattice

Authors: Xiancong Lu and E. Arrigoni

Categories: cond-mat.str-el

Comments: published version

Journal-ref: Phys. Rev. B 79, 245109 (2009)

\\ ( http://arxiv.org/abs/0902.0388 , 215kb)

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arXiv:0902.1069 (*cross-listing*)

replaced with revised version Mon, 22 Jun 2009 10:44:10 GMT (569kb)

Title: Dilute gas of ultracold two-level atoms inside a cavity; generalized

Dicke model

Authors: Jonas Larson, Maciej Lewenstein

Categories: quant-ph cond-mat.other

Comments: 10 pages, 7 figures

Journal-ref: New J. Phys. 11, 063027 (2009)

\\ ( http://arxiv.org/abs/0902.1069 , 569kb)

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arXiv:0903.2534

replaced with revised version Mon, 22 Jun 2009 14:57:51 GMT (1075kb)

Title: Vortex-Induced Phase Slip Dissipation in a Toroidal Bose-Einstein

Condensate Flowing Through a Barrier

Authors: F. Piazza, L. A. Collins, and A. Smerzi

Categories: cond-mat.other

Comments: Updated version. A discussion of an analytic criterion for the

instability of the superfluid is added. The case of vortex anti-vortex

annihilation is also added to the presented results of the numerical

simulations

\\ ( http://arxiv.org/abs/0903.2534 , 1075kb)

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arXiv:0903.3635

replaced with revised version Sat, 20 Jun 2009 01:12:19 GMT (1621kb,D)

Title: Dynamics of Cold Atoms Crossing a One-Way Barrier

Authors: Jeremy J. Thorn, Elizabeth A. Schoene, Tao Li, and Daniel A. Steck

Categories: physics.atom-ph

Comments: 20 pages, 20 figures; update to match published version

Journal-ref: Physical Review A vol. 79, 063402 (2009)

DOI: 10.1103/PhysRevA.79.063402

\\ ( http://arxiv.org/abs/0903.3635 , 1621kb)

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arXiv:0903.3570

replaced with revised version Tue, 23 Jun 2009 10:17:42 GMT (119kb)

Title: Combination of a magnetic Feshbach resonance and an optical

bound-to-bound transition

Authors: D.M. Bauer, M. Lettner, C. Vo, G. Rempe, S. D\"urr

Categories: cond-mat.other

Journal-ref: Physical Review A 79, 062713 (2009)

DOI: 10.1103/PhysRevA.79.062713

\\ ( http://arxiv.org/abs/0903.3570 , 119kb)

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arXiv:0903.4968

replaced with revised version Tue, 23 Jun 2009 14:16:04 GMT (29kb)

Title: Construction of a Coordinate Bethe Ansatz for the asymmetric simple

exclusion process with open boundaries

Authors: Damien Simon

Categories: cond-mat.stat-mech math-ph math.MP

Comments: references added, one new subsection and corrected typos

\\ ( http://arxiv.org/abs/0903.4968 , 29kb)

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arXiv:0906.0714 (*cross-listing*)

replaced with revised version Tue, 23 Jun 2009 09:58:54 GMT (1901kb)

Title: Towards a random laser with cold atoms

Authors: William Guerin (INLN), Nicolas Mercadier (INLN), Franck Michaud

(INLN), Davide Brivio (INLN), Luis S. Froufe-P\'erez, R\'emi Carminati (LOA),

Vitalie Eremeev (LPMMC), Arthur Goetschy (LPMMC), Sergey E. Skipetrov

(LPMMC), Robin Kaiser (INLN)

Categories: physics.atom-ph cond-mat.dis-nn physics.optics

Comments: Submitted to J. Opt. A for the special issue on nanolasers and random

lasers (to be published early 2010)

\\ ( http://arxiv.org/abs/0906.0714 , 1901kb)

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arXiv:0906.1686

replaced with revised version Tue, 23 Jun 2009 07:17:18 GMT (24kb)

Title: Quantum entanglement of spin-1 bosons with coupled ground states in

optical lattices

Authors: B. \"Oztop, M. \"O. Oktel, \"O. E. M\"ustecapl\i o\u{g}lu and L. You

Categories: cond-mat.quant-gas quant-ph

Comments: 18 pages, 8 figures. To be published in Journal of Physics B

Journal-ref: Journal of Physics B 42, 145505 (2009)

\\ ( http://arxiv.org/abs/0906.1686 , 24kb)

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arXiv:0903.4843

replaced with revised version Tue, 23 Jun 2009 13:55:12 GMT (31kb,D)

Title: Framed Hilbert space: hanging the quasi-probability pictures of quantum

theory

Authors: Christopher Ferrie, Joseph Emerson

Categories: quant-ph

Comments: 46 pages, 1 table, contains a review of finite dimensional

quasi-probability functions

Journal-ref: New J. Phys. 11 (2009) 063040

DOI: 10.1088/1367-2630/11/6/063040

\\ ( http://arxiv.org/abs/0903.4843 , 31kb)

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arXiv:0901.4719

replaced with revised version Thu, 25 Jun 2009 05:28:24 GMT (366kb)

Title: Bloch oscillations of Bose-Einstein condensates: Quantum counterpart of

dynamical instability

Authors: Andrey R. Kolovsky, Hans J\"urgen Korsch, Eva-Maria Graefe

Categories: quant-ph

Comments: 12 pages, 14 figures

\\ ( http://arxiv.org/abs/0901.4719 , 366kb)

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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 ========================================================================= _______________________________________________ Matts-arxiv mailing list Matts-arxiv_at_lists.sps.uq.edu.auReceived on Fri Aug 21 2009 - 14:14:01 EST

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