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

Date: Fri, 24 Aug 2007 09:30:12 +1000 (EST)

Date: Fri, 24 Aug 2007 09:30:12 +1000 (EST)

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

Hi everyone,

Firstly I would like to apologise for the delay in this posting, but for once I

have a good excuse. I usually try to compile this list on Monday mornings, but

not long after I arrived at work on August 6 my wife called me to say I

should get home quick and take her to the hospital. Less than three hours

later, Owen Joseph Davis made his way into the world. Hence I've had some time

off in the last couple of weeks :)

For those that are interested I've posted a few photos here

http://www.flickr.com/photos/matt0064/sets/72157601254687643/

I should have you up to date fairly shortly. Here is the first week's worth

that you have no doubt been anticipating: 31 new papers and 17 replacements.

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arXiv:0707.4061

Date: Fri, 27 Jul 2007 08:17:15 GMT (91kb)

Title: Generation of mesoscopic superpositions of a binary Bose-Einstein

condensate in a slightly asymmetric double well

Authors: Christoph Weiss (LKB - Lhomond), Niklas Teichmann (UMSIHP)

Categories: cond-mat.other

Comments: 5 pages, 4 figures, preprint-version

Proxy: ccsd hal-00165661

\\

A previous publication [Europhysics Letters 78, 10009 (2007)] suggested to

coherently generate mesoscopic superpositions of a two-component Bose-Einstein

condensate in a double well under perfectly symmetric conditions. However,

already tiny asymmetries can destroy the entanglement properties of the ground

state. Nevertheless, even under more realistic conditions, the scheme is

demonstrated numerically to generate mesoscopic superpositions.

\\ ( http://arxiv.org/abs/0707.4061 , 91kb)

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arXiv:0707.4066

Date: Fri, 27 Jul 2007 08:38:29 GMT (707kb)

Title: Fulde-Ferrell-Larkin-Ovchinnikov states in one-dimensional

spin-polarized ultracold atomic Fermi gases

Authors: Xia-Ji Liu, Hui Hu, and Peter D. Drummond

Categories: cond-mat.stat-mech cond-mat.str-el

Comments: 23 papes, 19 figures, submitted to Phys. Rev. A

\\

We present a systematic study of quantum phases in a one-dimensional

spin-polarized Fermi gas. Three comparative theoretical methods are used to

explore the phase diagram at zero temperature: the mean-field theory with

either an order parameter in a single-plane-wave form or a self-consistently

determined order parameter using the Bogoliubov-de Gennes equations, as well as

the exact soluble Bethe ansatz method. We find that a spatially inhomogeneous

Fulde-Ferrell-Larkin-Ovchinnikov phase, which lies between the fully paired BCS

state and the fully polarized normal state, dominates most of the phase diagram

of a uniform gas. The phase transition from the BCS state to the

Fulde-Ferrell-Larkin-Ovchinnikov phase is of second order, and therefore there

are no phase separation states in one-dimensional homogeneous polarized gases.

This is in sharp contrast to the three-dimensional situation, where a phase

separation regime is predicted to occupy a very large space in the phase

diagram. We conjecture that the prediction of the dominance of the phase

separation phases in three dimension could be an artifact of the

non-self-consistent mean-field approximation, which is heavily used in the

study of three-dimensional polarized Fermi gases. We consider also the effect

of a harmonic trapping potential on the phase diagram, and find that in this

case the trap generally leads to phase separation, in accord with the

experimental observations for a trapped gas in three dimension. We finally

investigate the local fermionic density of states of the

Fulde-Ferrell-Larkin-Ovchinnikov ansatz. A two-energy-gap structure is shown

up, which could be used as an experimental probe of the

Fulde-Ferrell-Larkin-Ovchinnikov states.

\\ ( http://arxiv.org/abs/0707.4066 , 707kb)

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arXiv:0707.4113

Date: Fri, 27 Jul 2007 13:44:08 GMT (133kb)

Title: Mean-field description of ultracold Bosons on disordered two-dimensional

optical lattices

Authors: P. Buonsante (1), Francesco Massel (1), Vittorio Penna (1), Alessandro

Vezzani (2) ((1) Dipartimento di Fisica, Torino Politecnico (2) Dipartimento

di Fisica, Universita' degli Studi di Parma)

Categories: cond-mat.dis-nn cond-mat.mes-hall

Comments: Accepted for publication on JPB-FTC

\\

In the present paper we describe the properties induced by disorder on an

ultracold gas of Bosonic atoms loaded into a two-dimensional optical lattice

with global confinement ensured by a parabolic potential. Our analysis is

centered on the spatial distribution of the various phases, focusing

particularly on the superfluid properties of the system as a function of

external parameters and disorder amplitude. In particular, it is shown how

disorder can suppress superfluidity, while partially preserving the system

coherence.

\\ ( http://arxiv.org/abs/0707.4113 , 133kb)

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arXiv:0707.4115

Date: Fri, 27 Jul 2007 13:49:35 GMT (146kb)

Title: Dynamics of the attractive 1D Bose gas: analytical treatment from

integrability

Authors: P. Calabrese and J.-S. Caux

Categories: cond-mat.str-el cond-mat.stat-mech

Comments: 26 pages, 5 figures

\\

The physics of the attractive one-dimensional Bose gas (Lieb-Liniger model)

is investigated with techniques based on the integrability of the system.

Combining a knowledge of particle quasi-momenta to exponential precision in the

system size with determinant representations of matrix elements of local

operators coming from the Algebraic Bethe Ansatz, we obtain rather general

analytical results for the zero-temperature dynamical correlation functions of

the density and field operators. Our results thus provide quantitative

predictions for possible future experiments in atomic gases or optical

waveguides.

\\ ( http://arxiv.org/abs/0707.4115 , 146kb)

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arXiv:0707.4119

Date: Fri, 27 Jul 2007 14:01:28 GMT (8kb)

Title: Supersymmetry and Goldstino Mode in Bose-Fermi Mixtures

Authors: Yue Yu and Kun Yang

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

Comments: 4 pages

\\

Supersymmetry is assumed to be a basic symmetry of the world in many high

energy theories, but none of the super partners of any known elementary

particle has been observed yet. We argue that supersymmetry can also be

realized and studied in ultracold atomic systems with a mixture of bosons and

fermions, with properly tuned interactions and single particle dispersion. We

further show that in such non-releativistic systems supersymmetry is either

spontaneously broken, or explicitly broken by a chemical potential difference

between the bosons and fermions. In both cases the system supports a sharp

fermionic collective mode or the so-called Goldstino, due to supersymmetry. We

also discuss possible ways to detect the Goldstino mode experimentally.

\\ ( http://arxiv.org/abs/0707.4119 , 8kb)

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arXiv:0707.4172

Date: Fri, 27 Jul 2007 21:51:27 GMT (104kb)

Title: Pairing states of a polarized Fermi gas trapped in a one-dimensional

optical lattice

Authors: A.E. Feiguin, and F. Heidrich-Meisner

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

Comments: 4 pages, 5 figs

\\

We study the properties of a one-dimensional (1D) gas of fermions trapped in

a lattice by means of the density matrix renormalization group method, focusing

on the case of unequal spin populations, and strong attractive interaction. In

the low density regime, the system phase-separates into a well defined

superconducting core and a fully polarized metallic cloud surrounding it. We

argue that the superconducting phase corresponds to a 1D analogue of the

Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, with a quasi-condensate of

tightly bound bosonic pairs with a finite center-of-mass momentum that scales

linearly with the magnetization. In the large density limit, the system allows

for four phases: in the core, we either find a Fock state of localized pairs or

a metallic shell with free spin-down fermions moving in a fully filled

background of spin-up fermions. As the magnetization increases, the Fock state

disappears to give room for a metallic phase, with a partially polarized

superconducting FFLO shell and a fully polarized metallic cloud surrounding the

core.

\\ ( http://arxiv.org/abs/0707.4172 , 104kb)

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arXiv:0707.4164

Date: Fri, 27 Jul 2007 19:02:25 GMT (18kb)

Title: Any-order propagation of the nonlinear Schroedinger equation

Authors: Frederick W. Strauch

Categories: quant-ph

Comments: 10 pages, no figures, submitted to Phys. Rev. E

\\

We derive an exact propagation scheme for nonlinear Schroedinger equations.

This scheme is entirely analogous to the propagation of linear Schroedinger

equations. We accomplish this by defining a special operator whose algebraic

properties ensure the correct propagation. As applications, we provide a simple

proof of a recent conjecture regarding higher-order integrators for the

Gross-Pitaevskii equation, extend it to multi-component equations, and to a new

class of integrators.

\\ ( http://arxiv.org/abs/0707.4164 , 18kb)

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arXiv:0707.4189

Date: Sat, 28 Jul 2007 12:27:30 GMT (176kb)

Title: Superfluid-Insulator Transition and Fermion Pairing in Bose-Fermi

Mixtures

Authors: Kun Yang

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

Comments: 4 pages with 4 embedded figures

\\

It is well known that bosons on an optical lattice undergo a second-order

superfluid-insulator transition (SIT) when the lattice potential increases. In

this paper we study SIT when fermions coexist with the bosons. We find that the

critical properties of particle-hole symmetric SIT with dynamical exponent z=1

is modified when fermions are present; it either becomes a fluctuation-driven

first order transition or a different second-order transition. On the other

hand the more generic particle-hole asymmetric (with z=2) SIT is stable against

coupling with fermions. We also discuss pairing interaction between fermions

mediated by quantum critical fluctuations near SIT.

\\ ( http://arxiv.org/abs/0707.4189 , 176kb)

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arXiv:0707.4259

Date: Sat, 28 Jul 2007 20:04:56 GMT (23kb)

Title: Fermi-Polaron: Diagrammatic Monte Carlo for Divergent Sign-Alternating

Series

Authors: Nikolay Prokof'ev and Boris Svistunov

Categories: cond-mat.stat-mech

Comments: 4 pages, 7 figures

\\

Diagrammatic Monte Carlo approach is applied to a problem of a single

spin-down fermion resonantly interacting with the sea of ideal spin-up

fermions. On one hand, we develop a generic, sign-problem tolerant, method of

exact numerical solution of polaron-type models. On the other hand, our

solution is important for understanding the phase diagram and properties of the

BCS-BEC crossover in the strongly imbalanced regime. This is the first, and

possibly characteristic, example of how the Monte Carlo approach can be applied

to a divergent sign-alternating diagrammatic series.

\\ ( http://arxiv.org/abs/0707.4259 , 23kb)

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arXiv:0707.4383

Date: Mon, 30 Jul 2007 12:31:02 GMT (152kb)

Title: Quantum rotor description of the Mott-insulator transition in the

Bose-Hubbard model

Authors: T. P. Polak and T. K. Kope\'c

Categories: cond-mat.stat-mech

Comments: accepted to PRB

\\

We present the novel approach to the Bose-Hubbard model using the

$\mathrm{U}(1)$ quantum rotor description. The effective action formalism

allows us to formulate a problem in the phase only action and obtain an

analytical formulas for the critical lines. We show that the nontrivial

$\mathrm{U}(1)$ phase field configurations have an impact on the phase

diagrams. The topological character of the quantum field is governed by terms

of the integer charges - winding numbers. The comparison presented results to

recently obtained quantum Monte Carlo numerical calculations suggests that the

competition between quantum effects in strongly interacting boson systems is

correctly captured by our model.

\\ ( http://arxiv.org/abs/0707.4383 , 152kb)

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arXiv:0707.4392

Date: Mon, 30 Jul 2007 12:38:08 GMT (22kb)

Title: An Effective Low-Dimensional Hamiltonian for Strongly Interacting Atoms

in a Transverse Trap

Authors: J. P. Kestner, L.-M. Duan

Categories: cond-mat.other

Comments: 4 pages, 1 figure

\\

We derive an effective low-dimensional Hamiltonian for strongly interacting

ultracold atoms in a transverse trapping potential near a wide Feshbach

resonance. The Hamiltonian includes crucial information about transverse

excitations in an effective model with renormalized interaction between atoms

and composite dressed molecules. We fix all the parameters in the Hamiltonian

for both one and two dimensional cases.

\\ ( http://arxiv.org/abs/0707.4392 , 22kb)

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arXiv:0707.4394

Date: Mon, 30 Jul 2007 13:44:10 GMT (76kb)

Title: Recent results from the Gaussian Quantum Monte Carlo method for fermions

with symmetry projection

Authors: P. Corboz, A. Kleine, F. F. Assaad, I. P. McCulloch, U. Schollw\"ock,

M. Troyer

Categories: cond-mat.str-el

Comments: 11 pages, 14 figures

\\

Gaussian Quantum Monte Carlo (GQMC) is a stochastic phase space method for

fermions with positive weights. In the example of the Hubbard model close to

half filling it fails to reproduce all the symmetries of the ground state

leading to systematic errors at low temperatures. In a previous work [Phys.

Rev. B {\bf 72}, 224518 (2005)] we proposed to restore the broken symmetries by

projecting the density matrix obtained from the simulation onto the ground

state symmetry sector. In this paper we present a systematic study of the

method for 2 and 3 leg Hubbard ladders for different fillings and on-site

repulsion strengths. We provide several indications that the systematic errors

stem from non-vanishing boundary terms in the partial integration step in the

derivation of the Fokker-Planck equation. Checking for spiking trajectories and

slow decaying probability distributions provides an important test of the

reliability of the results. Possible solutions to avoid boundary terms are

discussed. Furthermore we compare results obtained from two different sampling

methods: Reconfiguration of walkers and the Metropolis algorithm.

\\ ( http://arxiv.org/abs/0707.4394 , 76kb)

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arXiv:0707.4422

Date: Mon, 30 Jul 2007 14:09:23 GMT (64kb)

Title: Specific heat of a one-dimensional interacting Fermi system: the role of

anomalies

Authors: Andrey V. Chubukov, Dmitrii L. Maslov, and Ronojoy Saha

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

Comments: 21 pages, 6 figures

\\

We re-visit the issue of the temperature dependence of the specific heat for

interacting fermions in 1D. Of particular interest is the spin component C_s(T)

of the specific heat. Unlike the charge component which scales linearly with T,

C_s(T) was shown by a variety of bosonization technique to contain a cube of

the running backscattering amplitude g_1(T), and eventually to scale down as

T/\log^3 T. On the other hand, a perturbative expansion of C_s (T) in powers of

the bare amplitude g_1 contains terms g_1, g^2_1, g^3_1, etc. We study in

detail why the running amplitude g_1 (T) appears in C_s(T) only at third order,

but not earlier. We consider a model with two cutoffs, fermionic and bosonic --

Lambda_f and Lambda_b-- set by the bandwidth and by the momentum-dependent

interaction, respectively. We show that for Lambda_f>Lambda_b (assumed in all

previous papers), C_s (T) does contains the running amplitude g_1 (T), but only

at intermediate temperatures: Lambda_b < T <Lambda_f. At lower T, g_1 in C_s

(T) freezes on the scale Lambda_b. We find that a physically distinct

contribution to C_s (T), emerging at third order, contains the running

amplitude g_1 (T) down to the lowest temperatures. We also show how to obtain

the same results within the sine-Gordon model.

\\ ( http://arxiv.org/abs/0707.4422 , 64kb)

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arXiv:0707.4435

Date: Mon, 30 Jul 2007 16:17:34 GMT (83kb)

Title: Emulating Non-Abelian Topological Matter in Cold Atom Optical Lattices

Authors: V. W. Scarola and S. Das Sarma

Categories: cond-mat.other

\\

Certain proposed extended Bose-Hubbard models may exhibit topologically

ordered ground states with excitations obeying non-Abelian braid statistics. A

sufficient tuning of Hubbard parameters could yield excitation braiding rules

to allow implementation of a universal set of topologically protected quantum

gates. We discuss potential issues in realizing a model with a proposed

non-Abelian topologically ordered ground state using optical lattices

containing bosonic dipoles. Our direct implementation scheme does not realize

the necessary anisotropic hopping, anisotropic interactions, and low

temperatures. We briefly mention other implementation ideas which may alleviate

some of these problems.

\\ ( http://arxiv.org/abs/0707.4435 , 83kb)

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arXiv:0707.4444

Date: Mon, 30 Jul 2007 19:46:13 GMT (396kb)

Title: Bose-Einstein Condensates in Strongly Disordered Traps

Authors: T. Nattermann and V.L. Pokrovsky

Categories: cond-mat.stat-mech cond-mat.dis-nn

\\

A Bose-Einstein condensate in an external potential consisting of a

superposition of a harmonic and a random potential is considered theoretically.

From a semi-quantitative analysis we find the size, shape and excitation

energy as a function of the disorder strength. For positive scattering length

and sufficiently strong disorder the condensate decays into fragments each of

the size of the Larkin length ${\cal L}$. This state is stable over a large

range of particle numbers. The frequency of the breathing mode scales as

$1/{\cal L}^2$. For negative scattering length a condensate of size ${\cal L}$

may exist as a metastable state. These finding are generalized to anisotropic

traps.

\\ ( http://arxiv.org/abs/0707.4444 , 396kb)

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arXiv:0707.4397 (*cross-listing*)

Date: Mon, 30 Jul 2007 12:56:43 GMT (93kb)

Title: Ultracold collisions in magnetic fields: reducing inelastic cross

sections near Feshbach resonances

Authors: R. Adam Rowlands, Maykel Leonardo Gonzalez-Martinez and Jeremy M.

Hutson

Categories: physics.chem-ph physics.atm-clus physics.atom-ph

Comments: 9 pages, 9 figures

\\

We have carried out bound-state and low-energy quantum scattering

calculations on He + NH (triplet Sigma) in magnetic fields, with the NH

molecule in its n=1 rotationally excited states. We have explored the pattern

of levels as a function of magnetic field and identified the nearly good

quantum numbers in different regimes. We have used the bound-state calculations

to locate low-energy Feshbach resonances. When the magnetic field is used to

tune across such a resonance, the real and imaginary part of the scattering

length show asymmetric oscillations and peaks with amplitude between 1 and 3

Angstroms. The scattering length does not pass through a pole at resonance. The

resonant behavior is characterized by a complex resonant scattering length

a_res. The corresponding inelastic cross sections show troughs as well as peaks

near resonance. This may be important for efforts to achieve evaporative and

sympathetic cooling for molecules, because it offers the hope that inelastic

trap losses can be reduced by tuning close to a Feshbach resonance.

\\ ( http://arxiv.org/abs/0707.4397 , 93kb)

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arXiv:0707.4519

Date: Tue, 31 Jul 2007 01:33:17 GMT (100kb)

Title: Condensation Phenomena in the `Maxwell-Boltzmann' statistics

Authors: Jun Ohkubo

Categories: cond-mat.dis-nn cond-mat.stat-mech

Comments: 6 pages, 5 figures

\\

We study real-space condensation phenomena in a type of classical stochastic

processes (site-particle system), such as zero-range processes and urn models.

We here study a stochastic process in the Ehrenfest class, i.e., particles in a

site are distinguishable. In terms of the statistical mechanical analogue, the

Ehrenfest class obeys the Maxwell-Boltzmann statistics. It is revealed why the

condensation phenomenon is difficult to occur in the Ehrenfest class. In

addition, we discuss a model for the condensation phenomenon in the Ehrenfest

class. It becomes clear that the condensation phenomenon arises only in the

case with quenched disorder, and that the model shows three types of

condensation depending on the disorder parameters.

\\ ( http://arxiv.org/abs/0707.4519 , 100kb)

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arXiv:0707.4520

Date: Tue, 31 Jul 2007 01:43:15 GMT (21kb)

Title: Correlations Functions of One-Dimensional Lieb-Liniger Anyons

Authors: Ovidiu I. Patu, Vladimir E. Korepin, Dmitri V. Averin

Categories: cond-mat.stat-mech

Comments: 19 pages, RevTeX 4

\\

We have investigated the properties of a model of 1D anyons interacting

through a $\delta$-function repulsive potential. The structure of the

quasi-periodic boundary conditions for the anyonic field operators and the

many-anyon wavefunctions is clarified. The spectrum of the low-lying

excitations including the particle-hole excitations is calculated for periodic

and twisted boundary conditions. Using the ideas of the conformal field theory

we obtain the large-distance asymptotics of the density and field correlation

function at the critical temperature T=0 and at small finite temperatures. Our

expression for the field correlation function extends the results in the

literature obtained for harmonic quantum anyonic fluids.

\\ ( http://arxiv.org/abs/0707.4520 , 21kb)

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arXiv:0707.4530

Date: Tue, 31 Jul 2007 04:40:16 GMT (110kb)

Title: Stabilization of a Bose-Einstein droplet by hyperfine Rabi oscillations

Authors: Hiroki Saito, Randall G. Hulet, Masahito Ueda

Categories: cond-mat.other

Comments: 6 pages, 2 figures

\\

A self-trapped Bose-Einstein condensate is shown to be stabilized in

two-dimensional free space by Rabi oscillations between two hyperfine states

which make an effective interatomic interaction oscillate in time. The

stabilization mechanism is elucidated by using a two-component Gross-Pitaevskii

equation combined with a variational analysis. The parameter regime of

stability is investigated.

\\ ( http://arxiv.org/abs/0707.4530 , 110kb)

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arXiv:0707.4630

Date: Tue, 31 Jul 2007 14:44:08 GMT (192kb)

Title: Ground state properties of a homogeneous 2D system of Bosons with

dipolar interactions

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

Lozovik

Categories: cond-mat.other

Comments: Contribution to RPMBT14 conference. To be published in a volume of

the Series on Advances in Quantum Many-Body by World Scientific

\\

The ground-state phase properties of a two-dimensional Bose system with

dipole-dipole interactions is studied by means of quantum Monte Carlo

techniques. Limitations of mean-field theory in a two-dimensional geometry are

discussed. A quantum phase transition from gas to solid is found. Crystal is

tested for existence of a supersolid in the vicinity of the phase transition.

Existence of mesoscopic analogue of the off-diagonal long-range order is shown

in the one-body density matrix in a finite-size crystal. Non-zero superfluid

fraction is found in a finite-size crystal, the signal being dramatically

increased in presence of vacancies.

\\ ( http://arxiv.org/abs/0707.4630 , 192kb)

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arXiv:0707.4652

Date: Tue, 31 Jul 2007 16:39:10 GMT (955kb)

Title: Laser tweezers for atomic solitons

Authors: Alicia V. Carpentier, Juan Belmonte-Beitia, Humberto Michinel, and

Victor M. Perez-Garcia

Categories: cond-mat.other

Comments: 6 pages, 7 figures

\\

We describe a controllable and precise laser tweezers for Bose-Einstein

condensates of ultracold atomic gases. In our configuration, a laser beam is

used to locally modify the sign of the scattering length in the vicinity of a

trapped BEC. The induced attractive interactions between atoms allow to extract

and transport a controllable number of atoms. We analyze, through numerical

simulations, the number of emitted atoms as a function of the width and

intensity of the outcoupling beam. We also study different configurations of

our system, as the use of moving beams. The main advantage of using the control

laser beam to modify the nonlinear interactions in comparison to the usual way

of inducing optical forces, i.e. through linear trapping potentials, is to

improve the controllability of the outcoupled solitary wave-packet, which opens

new possibilities for engineering macroscopic quantum states.

\\ ( http://arxiv.org/abs/0707.4652 , 955kb)

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arXiv:0707.4668

Date: Tue, 31 Jul 2007 18:19:53 GMT (294kb)

Title: Atomic lattice excitons: from condensates to crystals

Authors: A. Kantian, A. J. Daley, P. Torma, P. Zoller

Categories: cond-mat.other

Comments: 19 pages, 15 figures

\\

We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed

by fermionic atoms in two bands of an optical lattice. Such a system provides a

clean setup to study fundamental properties of excitons, ranging from

condensation to exciton crystals (which appear for a large effective mass ratio

between particles and holes). Using both mean-field treatments and 1D numerical

computation, we discuss the properities of ALEs under varying conditions, and

discuss in particular their preparation and measurement.

\\ ( http://arxiv.org/abs/0707.4668 , 294kb)

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arXiv:0707.4624

Date: Tue, 31 Jul 2007 17:34:57 GMT (253kb)

Title: Conceptual Design of a Micron-Scale Atomic Clock

Authors: Eric C. Hannah, Michael A. Brown

Categories: physics.atom-ph physics.ins-det

Comments: Submitted to the Journal of Applied Physics

\\

A theoretical proposal for reducing an entire atomic clock to micron

dimensions. A phosphorus or nitrogen atom is introduced into a fullerene cage.

This endohedral fullerene is then coated with an insulating shell and a number

of them are deposited as a thin layer on a silicon chip. Next to this layer a

GMR sensor is fabricated which is close to the endohedral fullerenes. This GMR

sensor measures oscillating magnetic fields on the order of micro-gauss from

the nuclear spins varying at the frequency of the hyperfine transition (413 MHz

frequency). Given the micron scale and simplicity of this system only a few

transistors are needed to control the waveforms and to perform digital

clocking. This new form of atomic clock exhibits extremely low power (nano

watts), high vibration and shock resistance, stability on the order of 10^{-9},

and is compatible with MEMS fabrication and chip integration. As GMR sensors

continue to improve in sensitivity the stability of this form of atomic clock

will increase proportionately.

\\ ( http://arxiv.org/abs/0707.4624 , 253kb)

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arXiv:0708.0003

Date: Wed, 1 Aug 2007 19:54:15 GMT (206kb)

Title: One-dimensional quantum wires: A pedestrian approach to bosonization

Authors: Sebastian Eggert

Categories: cond-mat.str-el

Comments: 47 pages, 18 figures, lecture notes (A3 Foresight Summer School,

Korea, 2006). The most recent version can be found at

http://www.physik.uni-kl.de/eggert/papers/

\\

In these lecture notes we will consider systems in which the motion of

electrons is confined to one dimension (1D). In these so-called quantum wires

electron-electron interaction effects play an important role because the

restricted dimensions enhance the scattering between the electrons and

completely destroy the quasi-particle picture. New density wave excitations

appear that are described by bosonic operators. Here, we will develop this

bosonic description, following a pedestrian approach which does not require any

previous knowledge in field theory methods. These notes therefore serve as a

detailed introduction into bosonization by carefully deriving the most

fundamental formulas.

\\ ( http://arxiv.org/abs/0708.0003 , 206kb)

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arXiv:0708.0092

Date: Wed, 1 Aug 2007 08:51:33 GMT (297kb)

Title: Bistability and 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

\\

Fluctuations of the number of condensed atoms in a finite-size, weakly

interacting Bose gas confined in a box potential are investigated for

temperatures up to the critical region. We develop a recursive scheme that

allows to calculate condensate statistics for systems of few hundred particles

and an approximate approach applicable to systems with N~10000 particles. We

point out the importance of particle-number constrain for the statistics near

the critical region, which reveal a novel bistable phase of the condensate. Our

analysis is performed in the canonical ensemble and the excitations are

described in a self-consistent way within the Bogoliubov-Popov approximation.

\\ ( http://arxiv.org/abs/0708.0092 , 297kb)

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arXiv:0708.0154

Date: Wed, 1 Aug 2007 13:55:55 GMT (26kb)

Title: Upper limit on the transition temperature for non-ideal Bose gases

Authors: Wu-Sheng Dai and Mi Xie

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

Comments: 7 pages, 1 figure

Journal-ref: Ann. Phys. (New York) 322, 1771-1775 (2007)

\\

In this paper we show that for a non-ideal Bose gas there exists an upper

limit on the transition temperature above which Bose-Einstein condensation

cannot occur regardless of the pressure applied. Such upper limits for some

realistic Bose gases are estimated. This result implies that there may also

exist an upper limit on the transition temperature of superconductors.

\\ ( http://arxiv.org/abs/0708.0154 , 26kb)

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arXiv:0708.0208

Date: Wed, 1 Aug 2007 18:15:42 GMT (497kb)

Title: Collective oscillations in optical matter

Authors: F. J. Garcia de Abajo

Categories: cond-mat.soft cond-mat.other

Comments: 4 figures. Optics Express (in press)

\\

Atom and nanoparticle arrays trapped in optical lattices are shown to be

capable of sustaining collective oscillations of frequency proportional to the

strength of the external light field. The spectrum of these oscillations

determines the mechanical stability of the arrays. This phenomenon is studied

for dimers, strings, and two-dimensional planar arrays. Laterally confined

particles free to move along an optical channel are also considered as an

example of collective motion in partially-confined systems. The fundamental

concepts of dynamical response in optical matter introduced here constitute the

basis for potential applications to quantum information technology and signal

processing. Experimental realizations of these systems are proposed.

\\ ( http://arxiv.org/abs/0708.0208 , 497kb)

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arXiv:0708.0120

Date: Wed, 1 Aug 2007 10:48:34 GMT (214kb)

Title: A case study of the Hirsch index for 26 non-prominent physicists

Authors: Michael Schreiber

Categories: physics.soc-ph

Comments: 13 pages, 3 figures, accepted for publication in Annalen der Physik

(Ann. Phys.)

\\

The h index was introduced by Hirsch to quantify an individual's scientific

research output. It has been widely used in different fields to show the

relevance of the research work of prominent scientists. I have worked out 26

practical cases of physicists which are not so prominent. Therefore this case

study should be more relevant to discuss various features of the Hirsch index

which are interesting or disturbing or both for the more average situation. In

particular, I investigate quantitatively some pitfalls in the evaluation and

the influence of self-citations.

\\ ( http://arxiv.org/abs/0708.0120 , 214kb)

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arXiv:0708.0253

Date: Thu, 2 Aug 2007 01:01:23 GMT (63kb)

Title: Many-Body Quantum and Thermal Fluctuations in Josephson-Linked

Condensates

Authors: Chaohong Lee, Libin Fu, Yuri S. Kivshar

Categories: quant-ph

Comments: 4 pages, 4 figures

\\

We analyze many-body quantum and thermal fluctuations of phase coherence

between two Josephson-linked Bose-Einstein condensates with repulsive

interaction. For zero temperature, we find that the coherence fluctuations of

symmetric systems grow as $\sim E_C/E_J$ and the number squeezing increases as

$\sim N^2 E_C/E_J$, where E_C is the interaction energy, E_J is the tunneling

energy, and N is the total particle number. The coherence fluctuations are

suppressed dramatically due to an interplay between the system asymmetry and

interaction revealing interesting resonance effects. For finite temperatures,

the coherence fluctuations grow, and the formation of self-trapped states

causes an anomalous behavior. The results are in a good qualitative agreement

with the experimental data.

\\ ( http://arxiv.org/abs/0708.0253 , 63kb)

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arXiv:0708.0356

Date: Thu, 2 Aug 2007 14:46:05 GMT (8kb)

Title: Quantum phase diffusion of a Bose system: beyond the

Hartree-Fock-Bogoliubov approximation

Authors: Ferdinando de Pasquale, Gian Luca Giorgi

Categories: quant-ph

\\

A diffusion process is usually assumed for the phase of the order parameter

of a Bose system of finite size. The theoretical basis is limited to the so

called Bogoliubov approximation. We show that a suitable generalization of the

Hartree-Fock-Bogoliubov approach recovers phase diffusion.

\\ ( http://arxiv.org/abs/0708.0356 , 8kb)

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\\

arXiv:0708.0358

Date: Thu, 2 Aug 2007 14:51:19 GMT (176kb)

Title: Entanglement, BEC, and superfluid-like behavior of two-mode photon

systems

Authors: Ferdinando de Pasquale, Gian Luca Giorgi

Categories: quant-ph

\\

A system of two interacting photon modes, without constraints on the photon

number, in the presence of a Kerr nonlinearity, exhibits BEC if the transfer

amplitude is greater than the mode frequency. A symmetry-breaking field (SBF)

can be introduced by taking into account a classical electron current. The

ground state, in the limit of small nonlinearity, becomes a squeezed state, and

thus the modes become entangled. The smaller is the SBF, the greater is

entanglement. Superfluid-like behavior is observed in the study of entanglement

growth from an initial coherent state, since in the short-time range the growth

does not depend on the SBF amplitude, and on the initial state amplitude. On

the other hand, the latter is the only parameter which determines entanglement

in the absence of the SBF.

\\ ( http://arxiv.org/abs/0708.0358 , 176kb)

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The replacements:

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arXiv:cond-mat/0612664

replaced with revised version Fri, 27 Jul 2007 15:50:09 GMT (251kb)

Title: Vortex quantum creation and winding number scaling in a quenched spinor

Bose gas

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

Categories: cond-mat.other

Comments: 4+epsilon pages of RevTex4, 2 figures; to appear in Physical Review

Letters

\\ ( http://arxiv.org/abs/cond-mat/0612664 , 251kb)

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arXiv:cond-mat/0511647

replaced with revised version Mon, 30 Jul 2007 10:27:50 GMT (22kb)

Title: Thermodynamic properties of a trapped Bose gas : A diffusion Monte Carlo

study

Authors: S Datta

Categories: cond-mat.stat-mech

Comments: 19 pages, 12 figures

\\ ( http://arxiv.org/abs/cond-mat/0511647 , 22kb)

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arXiv:cond-mat/0702555

replaced with revised version Sat, 28 Jul 2007 19:45:08 GMT (36kb)

Title: Bold Diagrammatic Monte Carlo: When Sign Problem is Welcome

Authors: Nikolay Prokof'ev and Boris Svistunov

Categories: cond-mat.stat-mech cond-mat.str-el

Comments: 4 pages, 2 figures, revtex4

\\ ( http://arxiv.org/abs/cond-mat/0702555 , 36kb)

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arXiv:cond-mat/0511647

replaced with revised version Tue, 31 Jul 2007 03:01:07 GMT (22kb)

Title: Thermodynamic properties of a trapped Bose gas : A diffusion Monte Carlo

study

Authors: S Datta

Categories: cond-mat.stat-mech

Comments: 19 pages, 12 figures

\\ ( http://arxiv.org/abs/cond-mat/0511647 , 22kb)

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arXiv:cond-mat/0610198

replaced with revised version Tue, 31 Jul 2007 11:28:40 GMT (193kb)

Title: Quantum liquid of repulsively bound pairs of particles in a lattice

Authors: David Petrosyan, Bernd Schmidt, James R. Anglin, Michael Fleischhauer

Categories: cond-mat.other quant-ph

Comments: Modified, expanded text, added figures

\\ ( http://arxiv.org/abs/cond-mat/0610198 , 193kb)

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\\

arXiv:0707.3320

replaced with revised version Tue, 31 Jul 2007 02:37:46 GMT (8kb)

Title: Discontinuity in the specific heat of a weakly interacting Bose gas

Authors: Sang-Hoon Kim

Categories: cond-mat.stat-mech

Comments: 2 pages, 2 figures

\\ ( http://arxiv.org/abs/0707.3320 , 8kb)

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arXiv:cond-mat/0305669

replaced with revised version Wed, 1 Aug 2007 09:21:22 GMT (67kb)

Title: Meissner effect in a charged Bose gas with short-range repulsion

Authors: Shun-ichiro Koh

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

Comments: 8 pages, 3 figures

Journal-ref: Physical Review B 68,144502(2003)

DOI: 10.1103/PhysRevB.68.144502

\\ ( http://arxiv.org/abs/cond-mat/0305669 , 67kb)

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arXiv:cond-mat/0601496

replaced with revised version Wed, 1 Aug 2007 12:31:50 GMT (482kb)

Title: The ground state of a mixture of two species of fermionic atoms in 1D

optical lattice

Authors: Shi-Jian Gu, Rui Fan, and Hai-Qing Lin

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

Comments: 9 pages, 10 figures, extended version

\\ ( http://arxiv.org/abs/cond-mat/0601496 , 482kb)

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\\

arXiv:cond-mat/0603479

replaced with revised version Wed, 1 Aug 2007 02:43:02 GMT (9kb)

Title: Ground state energy density of a dilute Bose gas in the canonical

transformation

Authors: Sang-Hoon Kim, Chul Koo Kim, and Mukunda P. Das

Categories: cond-mat.stat-mech

Comments: 5 pages, 0 figure

\\ ( http://arxiv.org/abs/cond-mat/0603479 , 9kb)

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arXiv:quant-ph/0611240

replaced with revised version Wed, 1 Aug 2007 08:56:09 GMT (173kb)

Title: Ultracold atoms in radio-frequency-dressed potentials beyond the

rotating wave approximation

Authors: S. Hofferberth, B. Fischer, T. Schumm, J. Schmiedmayer, and I.

Lesanovsky

Categories: quant-ph

Comments: 6 pages, 4 figures

Journal-ref: Phys. Rev. A 76, 013401 (2007)

\\ ( http://arxiv.org/abs/quant-ph/0611240 , 173kb)

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arXiv:cond-mat/0701744

replaced with revised version Thu, 2 Aug 2007 05:46:16 GMT (169kb)

Title: Universal thermodynamics of strongly interacting Fermi gases

Authors: Hui Hu, Peter D. Drummond, and Xia-Ji Liu

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

Comments: 5 pages + 3 figures, submitted for publication

Journal-ref: Nature Physics, Vol 3 (2007)469

\\ ( http://arxiv.org/abs/cond-mat/0701744 , 169kb)

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arXiv:cond-mat/0702569

replaced with revised version Thu, 2 Aug 2007 04:04:31 GMT (23kb)

Title: Quantum rearrangement and self-consistent BCS-BEC crossover

thermodynamics

Authors: Ji-sheng Chen, Chuan-ming Cheng, Jia-rong Li, Yan-ping Wang

Categories: cond-mat.stat-mech hep-ph nucl-th

Comments: published version revised according to comments; a few typos fixed

and references updated

\\ ( http://arxiv.org/abs/cond-mat/0702569 , 23kb)

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\\

arXiv:0705.0972

replaced with revised version Thu, 2 Aug 2007 00:27:14 GMT (15kb)

Title: Fermionic stabilization and density-wave ground state of a polar

condensate

Authors: O.Dutta R. Kanamoto and P.Meystre

Categories: cond-mat.other

\\ ( http://arxiv.org/abs/0705.0972 , 15kb)

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arXiv:0706.2259

replaced with revised version Thu, 2 Aug 2007 08:26:42 GMT (138kb)

Title: Non-equilibrium coherence dynamics in one-dimensional Bose gases

Authors: S. Hofferberth, I. Lesanovsky, B. Fischer, T. Schumm, J. Schmiedmayer

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

Comments: to appear in nature

\\ ( http://arxiv.org/abs/0706.2259 , 138kb)

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arXiv:0707.4172

replaced with revised version Thu, 2 Aug 2007 18:38:26 GMT (104kb)

Title: Pairing states of a polarized Fermi gas trapped in a one-dimensional

optical lattice

Authors: A.E. Feiguin, and F. Heidrich-Meisner

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

Comments: 4 pages, 5 figs

\\ ( http://arxiv.org/abs/0707.4172 , 104kb)

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arXiv:quant-ph/0701110

replaced with revised version Thu, 2 Aug 2007 18:45:29 GMT (114kb)

Title: Preparing and probing atomic number states with an atom interferometer

Authors: J. Sebby-Strabley, B. L. Brown, M. Anderlini, P. J. Lee, P. R.

Johnson, W. D. Phillips, and J. V. Porto

Categories: quant-ph

Journal-ref: Phys. Rev. Lett. 98 200405 (2007)

DOI: 10.1103/PhysRevLett.98.200405

\\ ( http://arxiv.org/abs/quant-ph/0701110 , 114kb)

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arXiv:0707.1653

replaced with revised version Thu, 2 Aug 2007 17:10:50 GMT (99kb)

Title: Chaos in kicked Bose-Einstein condensates: Bogoliubov resonances

Authors: J. Reslen, C.E. Creffield, and T.S. Monteiro

Categories: quant-ph

Comments: 5 pages

\\ ( http://arxiv.org/abs/0707.1653 , 99kb)

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-- ========================================================================= Dr M. J. Davis, Senior Lecturer in Physics School of Physical Sciences, email: mdavis_at_physics.uq.edu.au University of Queensland, ph : +61 7 334 69824 Brisbane, QLD 4072, fax : +61 7 336 51242 Australia. http://www.physics.uq.edu.au/people/mdavis/ ========================================================================= 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 Aug 24 2007 - 09:30:12 EST

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