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

Date: Mon, 15 May 2006 10:28:53 +1000 (EST)

Date: Mon, 15 May 2006 10:28:53 +1000 (EST)

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

Lots of interesting papers this week.

List home page is:

http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/

The abstracts:

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Paper: cond-mat/0605138

Date: Fri, 5 May 2006 12:40:09 GMT (52kb)

Title: Landau functions for non-interacting bosons

Authors: Andreas Sinner, Florian Schuetz, and Peter Kopietz

Comments: 4 pages, 4 figures

Subj-class: Statistical Mechanics

\\

We define and calculate the Landau functions and the associated order

parameter probability distributions for Bose-Einstein condensation (BEC) and

spontaneous symmetry breaking (SSB) of non-interacting bosons within a

canonical ensemble. We show that even for finite clusters consisting of N >= 2

bosons there is an unambiguously defined critical temperature where the Landau

function continuously develops minima at a finite value of the relevant order

parameter. For infinite systems BEC and SSB are described by the same Landau

function whose shape exhibits a rather complicated dependence on the

dimensionality and on the form of the external potential.

\\ ( http://arXiv.org/abs/cond-mat/0605138 , 52kb)

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Paper: cond-mat/0605140

Date: Fri, 5 May 2006 12:56:13 GMT (37kb)

Title: Phase separations of bosonic mixtures in optical lattices from

macroscopic to microscopic scales

Authors: Ofir E. Alon, Alexej I. Streltsov and Lorenz S. Cederbaum

Comments: 12 pages, 3 figures

Subj-class: Other

\\

Mixtures of cold bosonic atoms in optical lattices undergo phase separations

on different length scales with increasing inter-species repulsion. As a

general rule, the stronger the intra-species interactions, the shorter is this

length scale. The wealth of phenomena is documented by illustrative examples on

both superfluids and Mott-insulators.

\\ ( http://arXiv.org/abs/cond-mat/0605140 , 37kb)

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Paper: cond-mat/0605143

Date: Fri, 5 May 2006 15:11:25 GMT (68kb)

Title: Classification of zero-energy resonances by dissociation of Feshbach

molecules

Authors: Thomas M. Hanna, Krzysztof Goral, Emilia Witkowska, Thorsten Koehler

Comments: 10 pages, 5 eps figures

Subj-class: Other

\\

We study the dissociation of Feshbach molecules by a magnetic field sweep

across a zero-energy resonance. In the limit of an instantaneous magnetic field

change, the distribution of atomic kinetic energy can have a peak indicating

dominance of the molecular closed-channel spin configuration over the entrance

channel. The extent of this dominance influences physical properties such as

stability with respect to collisions, and so the readily measurable presence or

absence of the corresponding peak provides a practical method of classifying

zero-energy resonances. Currently achievable ramp speeds, e.g. those

demonstrated by Duerr et al. [Phys. Rev. A 70, 031601 (2005)], are fast enough

to provide magnetic field changes that may be interpreted as instantaneous. We

study the transition from sudden magnetic field changes to asymptotically wide,

linear ramps. In the latter limit, the predicted form of the atomic kinetic

energy distribution is independent of the specific implementation of the

two-body physics, provided that the near-resonant scattering properties are

properly accounted for.

\\ ( http://arXiv.org/abs/cond-mat/0605143 , 68kb)

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Paper: cond-mat/0605148

Date: Fri, 5 May 2006 16:18:15 GMT (8kb)

Title: Bose-Einstein condensation and entanglement in magnetic systems

Authors: Mucio A. Continentino

Comments: 4 pages, 1 Table

Subj-class: Strongly Correlated Electrons; Statistical Mechanics

\\

We present a study of magnetic field induced quantum phase transitions in

insulating systems. A generalized scaling theory is used to obtain the

temperature dependence of several physical quantities along the quantum

critical trajectory ($H=H_{C}$, $T\to0$) where $H$ is a longitudinal external

magnetic field and $H_{C}$ the critical value at which the transition occurs.

We consider transitions from a spin liquid at a critical field $H_{C1}$ and

from a fully polarized paramagnet, at $H_{C2}$, into phases with long range

order in the transverse components. The transitions at $H_{C1}$ and $H_{C2}$

can be viewed as Bose-Einstein condensations of magnons which however belong to

different universality classes since they have different values of the dynamic

critical exponent $z$. Finally, we use that the magnetic susceptibility is an

entanglement witness to discuss how this type of correlation sets in as the

system approaches the quantum critical point along the critical trajectory,

$H=H_{C2}$, $T\to0$.

\\ ( http://arXiv.org/abs/cond-mat/0605148 , 8kb)

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Paper: quant-ph/0605055

Date: Fri, 5 May 2006 14:06:40 GMT (53kb)

Title: Atom interferometry

Authors: Alain Miffre (LCAR), Marion Jacquey (LCAR), Matthias B\"{u}chner

(LCAR), G\'{e}rard Tr\'{e}nec (LCAR), Jacques Vigu\'{e} (LCAR)

Comments: submitted to Physica Scripta as a Comment on Atomic Molecular and

Optical Physics

Proxy: ccsd ccsd-00023896

\\

In this paper, we present a brief overview of atom interferometry. This field

of research has developed very rapidly since 1991. Atom and light wave

interferometers present some similarities but there are very important

differences in the tools used to manipulate these two types of waves. Moreover,

the sensitivity of atomic waves and light waves to their environment is very

different. Atom interferometry has already been used for a large variety of

studies: measurements of atomic properties and of inertial effects

(accelerations and rotations), new access to some fundamental constants,

observation of quantum decoherence, etc. We review the techniques used for a

coherent manipulation of atomic waves and the main applications of atom

interferometers.

\\ ( http://arXiv.org/abs/quant-ph/0605055 , 53kb)

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Paper: quant-ph/0605059

Date: Fri, 5 May 2006 16:12:28 GMT (216kb)

Title: Creation of macroscopic superpositions of flow states with Bose-Einstein

condensates

Authors: Jacob Dunningham and David Hallwood

Comments: 9 pages, 7 figures

\\

We present a straightforward scheme for creating macroscopic superpositions

of different superfluid flow states of Bose-Einstein condensates trapped in

optical lattices. This scheme has the great advantage that all the techniques

required are achievable with current experiments. Furthermore, the relative

difficulty of creating cats scales favorably with the size of the cat. This

means that this scheme may be well-suited to creating superpositions involving

large numbers of particles. Such states may have interesting technological

applications such as making quantum-limited measurements of angular momentum.

\\ ( http://arXiv.org/abs/quant-ph/0605059 , 216kb)

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Paper: cond-mat/0605154

Date: Fri, 5 May 2006 22:23:19 GMT (17kb)

Title: Fractionalization in Bosonic Extended Hubbard Models : Emergence of

Artificial Photons in an Optical Lattice

Authors: Sumanta Tewari, V. W. Scarola, T. Senthil, S. Das Sarma

Comments: 4+ pages, 1 eps figure

Subj-class: Strongly Correlated Electrons

\\

We establish the theoretical feasibility of direct analog simulation of the

compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We

discuss the realizability of various fractionalized topological phases in

extended Bose-Hubbard models in several optical lattice geometries. We predict

the testable signatures of the emergent U(1) Coulomb phase in noise correlation

measurements, thus suggesting the possible emergence of artificial light in

optical lattices.

\\ ( http://arXiv.org/abs/cond-mat/0605154 , 17kb)

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Paper: cond-mat/0605163

Date: Sat, 6 May 2006 15:06:55 GMT (156kb)

Title: Mean-field phase diagram of disordered bosons in a lattice at non-zero

temperature

Authors: K.V.Krutitsky, A.Pelster and R.Graham

Subj-class: Other; Disordered Systems and Neural Networks

\\

Bosons in a periodic lattice with on-site disorder at low but non-zero

temperature are considered within a mean-field theory. We show that, not only

at vanishing but also at non-zero temperature, both the Mott-insulator and the

Bose-glass phase are unambiguously distinguished by their density of states at

small energies. We obtain the phase diagram of these phases as well as the

superfluid.

\\ ( http://arXiv.org/abs/cond-mat/0605163 , 156kb)

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Paper: cond-mat/0605169

Date: Sun, 7 May 2006 15:04:33 GMT (248kb)

Title: Fermion pairing with spin-density imbalance in an optical lattice

Authors: T. Koponen, J. Kinnunen, J.-P. Martikainen, L.M. Jensen, and P. Torma

Comments: 18 pages, 16 figures

Subj-class: Superconductivity; Materials Science

\\

We consider pairing in a two-component atomic Fermi gas, in a

three-dimensional optical lattice, when the components have unequal densities,

i.e. the gas is polarized. We show that a superfluid where the translational

symmetry is broken by a finite Cooper pair momentum, namely an FFLO-type state,

minimizes the Helmholtz free energy of the system. We demonstrate that such a

state is clearly visible in the observable momentum distribution of the atoms,

and analyze the dependence of the order parameter and the momentum distribution

on the filling fraction and the interaction strength.

\\ ( http://arXiv.org/abs/cond-mat/0605169 , 248kb)

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Paper: cond-mat/0605180

Date: Mon, 8 May 2006 08:00:49 GMT (913kb)

Title: Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas

Authors: Y. H. Pong, C. K. Law

Comments: 14 pages, 4 figures, submitted to Phys. Rev. A

Subj-class: Other

\\

We examine the basic mode structure of atomic Cooper pairs in an

inhomogeneous Fermi gas. Based on the properties of Bogoliubov quasi-particle

vacuum, the single particle density matrix and the anomalous density matrix

share the same set of eigenfunctions. These eigenfunctions correspond to

natural pairing orbits associated with the BCS ground state. We investigate

these orbits for a Fermi gas in a spherical harmonic trap, and construct the

wave function of a Cooper pair in the form of Schmidt decomposition. The issue

of spatial quantum entanglement between constituent atoms in a pair is

addressed.

\\ ( http://arXiv.org/abs/cond-mat/0605180 , 913kb)

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Paper: cond-mat/0605183

Date: Mon, 8 May 2006 08:57:36 GMT (508kb)

Title: Detecting phonons and persistent currents in toroidal Bose-Einstein

condensates by means of pattern formation

Authors: M. Modugno, C. Tozzo, F. Dalfovo

Comments: 4 pages, 4 figures

Subj-class: Other

\\

We theoretically investigate the dynamic properties of a Bose-Einstein

condensate in a toroidal trap. A periodic modulation of the transverse

confinement is shown to produce a density pattern due to parametric

amplification of phonon pairs. By imaging the density distribution after free

expansion one obtains i) a precise determination of the Bogoliubov spectrum and

ii) a sensitive detection of quantized circulation in the torus. The parametric

amplification is also sensitive to thermal and quantum fluctuations.

\\ ( http://arXiv.org/abs/cond-mat/0605183 , 508kb)

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Paper: cond-mat/0605184

Date: Mon, 8 May 2006 10:11:07 GMT (832kb)

Title: A Mott state of molecules

Authors: T. Volz, N. Syassen, D. M. Bauer, E. Hansis, S. D\"urr, G. Rempe

Subj-class: Statistical Mechanics

\\

Mott insulators of ultracold gases in optical lattices are of great interest,

because they represent strongly correlated many-body systems with quantum

states that cannot be described as simple products of single-particle wave

functions. These systems bear a great potential for applications in quantum

simulations and quantum information processing, in particular when using

particles with a long-range dipole-dipole interaction, such as polar molecules.

Here we show the realization of a Mott state of molecules. The molecules are

produced from an atomic Mott insulator with a density profile chosen such that

the central region of the gas contains two atoms per lattice site. A Feshbach

resonance is used to associate the atom pairs to molecules. Remaining atoms can

be removed with blast light. In order to show that the resulting state is a

molecular Mott state, the molecules are dissociated and the lattice depth is

reduced. This restores phase coherence which is seen in time-of-flight images.

\\ ( http://arXiv.org/abs/cond-mat/0605184 , 832kb)

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Paper: cond-mat/0605196

Date: Mon, 8 May 2006 14:33:01 GMT (614kb)

Title: Repulsively bound atom pairs in an optical lattice

Authors: K. Winkler, G. Thalhammer, F. Lang, R. Grimm, J. Hecker Denschlag, A.

J. Daley, A. Kantian, H. P. Buechler, P. Zoller

Comments: 5 pages, 4 figures

Subj-class: Other

\\

Throughout physics, stable composite objects are usually formed via

attractive forces, which allow the constituents to lower their energy by

binding together. Repulsive forces separate particles in free space. However,

in a structured environment such as a periodic potential and in the absence of

dissipation, stable composite objects can exist even for repulsive

interactions. Here we report on the first observation of such an exotic bound

state, comprised of a pair of ultracold atoms in an optical lattice. Consistent

with our theoretical analysis, these repulsively bound pairs exhibit long

lifetimes, even under collisions with one another. Signatures of the pairs are

also recognised in the characteristic momentum distribution and through

spectroscopic measurements. There is no analogue in traditional condensed

matter systems of such repulsively bound pairs, due to the presence of strong

decay channels. These results exemplify on a new level the strong

correspondence between the optical lattice physics of ultracold bosonic atoms

and the Bose-Hubbard model, a correspondence which is vital for future

applications of these systems to the study of strongly correlated condensed

matter systems and to quantum information.

\\ ( http://arXiv.org/abs/cond-mat/0605196 , 614kb)

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Paper: cond-mat/0605197

Date: Mon, 8 May 2006 15:07:06 GMT (163kb)

Title: Calogero-Sutherland-Lieb-Liniger gas in one-dimensional cold atoms

Authors: Yue Yu

Comments: 5 pages, 5 figures

Subj-class: Other; Statistical Mechanics

\\

We study an array of cigar-like Bose atom condensates confined in a cylinder

and examine the competition between the dipole-dipole and the short range

interactions. The system is effectively reduced to a one-dimensional boson one

with a contact and inverse square interactions. We call this system the

Calogero-Sutherland-Lieb-Liniger gas. The universal properties of the ground

state are analyzed by the renormalization group theory. By using the

bosonization techniques to the excluson gas, we calculate the non-universal

exponent depending on the microscopic parameters. This exponent may be

experimentally measurable.

\\ ( http://arXiv.org/abs/cond-mat/0605197 , 163kb)

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Paper: cond-mat/0605198

Date: Mon, 8 May 2006 15:34:40 GMT (736kb)

Title: Cooling toolbox for atoms in optical lattices

Authors: M. Popp, J.-J. Garcia-Ripoll, K. G. H. Vollbrecht and J. I. Cirac

Comments: 14 pages, 13 figures

Subj-class: Other

\\

We propose and analyze several schemes for cooling bosonic and fermionic

atoms in an optical lattice potential close to the ground state of the

no-tunnelling regime. Some of the protocols rely on the concept of algorithmic

cooling, which combines occupation number filtering with ideas from ensemble

quantum computation. We also design algorithms that create an ensemble of

defect-free quantum registers. We study the efficiency of our protocols for

realistic temperatures and in the presence of a harmonic confinement. We also

propose an incoherent physical implementation of filtering which can be

operated in a continuous way.

\\ ( http://arXiv.org/abs/cond-mat/0605198 , 736kb)

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Paper: cond-mat/0602620

replaced with revised version Mon, 8 May 2006 10:42:41 GMT (18kb)

Title: Composite-fermion description of rotating Bose gases at low angular

momenta

Authors: Nicolay Korslund and Susanne Viefers

Comments: 7 pages (RevTeX), 1 figure. Slightly revised version (accepted for

publication in Phys Rev A)

Report-no: OSLO-TP 1-06

Subj-class: Mesoscopic Systems and Quantum Hall Effect

\\ ( http://arXiv.org/abs/cond-mat/0602620 , 18kb)

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Paper: cond-mat/0603424

replaced with revised version Mon, 8 May 2006 16:17:57 GMT (331kb)

Title: Superfluid Dynamics of a Bose-Einstein Condensate in a One Dimensional

Optical Super-Lattice

Authors: Aranya B Bhattacherjee

Comments: 18 pages

Subj-class: Statistical Mechanics

\\ ( http://arXiv.org/abs/cond-mat/0603424 , 331kb)

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Paper: cond-mat/0604424

replaced with revised version Mon, 8 May 2006 07:28:29 GMT (164kb)

Title: Non-BCS superfluidity in trapped ultracold Fermi gases

Authors: L. M. Jensen, J. Kinnunen, and P. Torma

Comments: Misprints corrected, references added

Subj-class: Strongly Correlated Electrons; Other

\\ ( http://arXiv.org/abs/cond-mat/0604424 , 164kb)

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Paper: cond-mat/0604464

replaced with revised version Mon, 8 May 2006 14:49:56 GMT (119kb)

Title: Quantum theory of an atom laser originating from a Bose-Einstein

condensate or a Fermi gas in the presence of gravity

Authors: Tobias Kramer and Mirta Rodriguez

Comments: 13 pages, 8 figures, slightly expanded version

Subj-class: Other; Atomic Physics

\\ ( http://arXiv.org/abs/cond-mat/0604464 , 119kb)

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Paper: quant-ph/0605075

Date: Mon, 8 May 2006 11:51:59 GMT (340kb)

Title: Cavity-QED entangled photon source based on two truncated Rabi

oscillations

Authors: R. Garcia-Maraver, K. Eckert, R. Corbalan, and J. Mompart

Comments: 18 pages, 9 figures; submitted for the "Optical Quantum Information

Science Special Issue" of JOSA B

\\

We discuss a cavity-QED scheme to deterministically generate entangled

photons pairs by using a three-level atom successively coupled to two single

longitudinal mode high-Q cavities presenting polarization degeneracy. The first

cavity is prepared in a well defined Fock state with two photons with opposite

circular polarizations while the second cavity remains in the vacuum state. A

half-of-a-resonant Rabi oscillation in each cavity transfers one photon from

the first to the second cavity, leaving the photons entangled in their

polarization degree of freedom. The feasibility of this implementation and some

practical considerations are discussed for both, microwave and optical regimes.

In particular, Monte Carlo wave function simulations have been performed with

state-of-the-art parameter values to evaluate the success probability of the

cavity-QED source in producing entangled photon pairs as well as its

entanglement capability.

\\ ( http://arXiv.org/abs/quant-ph/0605075 , 340kb)

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Paper: physics/0605052

Date: Sat, 6 May 2006 04:36:30 GMT (420kb)

Title: Cooling in reduced period optical lattices: non-zero Raman detuning

Authors: V. S. Malinovsky and P. R. Berman

Subj-class: Atomic Physics; General Physics

\\

In a previous paper [Phys. Rev. A 72, 033415 (2005)], it was shown that

sub-Doppler cooling occurs in a standing-wave Raman scheme (SWRS) that can lead

to reduced period optical lattices. These calculations are extended to allow

for non-zero detuning of the Raman transitions. New physical phenomena are

encountered, including cooling to non-zero velocities, combinations of Sisyphus

and "corkscrew" polarization cooling, and somewhat unusual origins of the

friction force. The calculations are carried out in a semi-classical

approximation and a dressed state picture is introduced to aid in the

interpretation of the results.

\\ ( http://arXiv.org/abs/physics/0605052 , 420kb)

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Paper: cond-mat/0605206

Date: Tue, 9 May 2006 02:58:58 GMT (96kb)

Title: Stabilization of BEC droplet in free space by feedback control of

interatomic interaction

Authors: Hiroki Saito and Masahito Ueda

Comments: 7 pages, 6 figures

Subj-class: Other

\\

A self-trapped Bose-Einstein condensate in three-dimensional free space is

shown to be stabilized by feedback control of the interatomic interaction

through nondestructive measurement of the condensate's peak column density. The

stability is found to be robust against poor resolution and experimental errors

in the measurement.

\\ ( http://arXiv.org/abs/cond-mat/0605206 , 96kb)

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Paper: cond-mat/0605207

Date: Mon, 8 May 2006 18:12:07 GMT (42kb)

Title: Entanglement entropy and entanglement witnesses in models of strongly

interacting low-dimensional fermions

Authors: V. V. Fran\c{c}a and K. Capelle

Comments: 5 pages, 5 figures

Subj-class: Strongly Correlated Electrons; Statistical Mechanics

\\

We investigate the behaviour of an entanglement measure (the local von Neuman

entropy ${\cal E}$) and an entanglement witness (the spin susceptibility

$\chi$) in models of strongly correlated fermions with metallic, insulating and

superconducting phases. ${\cal E}$ changes drastically at quantum critical

points, such as the Mott metal-insulator transition, but also at the smoother

crossover from the BCS to the Bose-Einstein regime of paired particles.

Nontrivial dependence of ${\cal E}$ on the system parameters is observed

throughout the phase diagram, even away from critical points and lines, but

${\cal E}$ is found not to be a state function in the thermodynamic sense.

Hilbert space restrictions can lead to counterintuitive behaviour of ${\cal

E}$. The spin susceptibility is shown to be a faithfull entanglement marker,

but its dependence on the nature of the underlying particle-particle

interactions is nontrivial. The opening of spin gaps in antiferromagnetic

insulators is numerically shown to be associated with enhanced entanglement.

\\ ( http://arXiv.org/abs/cond-mat/0605207 , 42kb)

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Paper: cond-mat/0605218

Date: Tue, 9 May 2006 06:28:12 GMT (42kb)

Title: Supersolid phases in the one dimensional extended soft core Bosonic

Hubbard model

Authors: G.G. Batrouni, F. Hebert, R.T. Scalettar

Comments: 4 pages, 5 figures

Subj-class: Superconductivity; Statistical Mechanics

\\

We present results of Quantum Monte Carlo simulations for the soft core

extended bosonic Hubbard model in one dimension. By studying the superfluid

density, the compressibility and the structure factor, we show that, contrary

to previous claims, supersolid phases are present, similar to those recently

shown to exist in two dimensions. We find the dynamic critical exponent z=1 for

the insulator-superfluid transition and z=2 for the insulator-supersolid

transition. The mechanism behind this difference is discussed. The simultaneous

presence of two types of quasi long range order results in two soliton-like

dips in the excitation spectrum.

\\ ( http://arXiv.org/abs/cond-mat/0605218 , 42kb)

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Paper: cond-mat/0605005

replaced with revised version Tue, 9 May 2006 18:52:15 GMT (49kb)

Title: Phase Transition in Imbalanced Fermion Superfluids

Authors: Heron Caldas

Comments: This is an invited contribution to a book titled "Pairing beyond BCS

Theory in Fermionic Systems" (Mark Alford, John Clark and Armen Sedrakian,

eds.), to be published by World Scientific. 3 figures, 12 pages, added more

references

Subj-class: Superconductivity; Strongly Correlated Electrons

\\ ( http://arXiv.org/abs/cond-mat/0605005 , 49kb)

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Paper: cond-mat/0605258

Date: Wed, 10 May 2006 10:56:53 GMT (751kb)

Title: Direct Observation of the Superfluid Phase Transition in Ultracold Fermi

Gases

Authors: Martin W. Zwierlein, Christian H. Schunck, Andre Schirotzek, and

Wolfgang Ketterle

Comments: 16 pages (incl. Supplemental Material), 5 figures

Subj-class: Superconductivity; Strongly Correlated Electrons

\\

Water freezes into ice, atomic spins spontaneously align in a magnet, liquid

helium becomes superfluid: Phase transitions are dramatic phenomena. However,

despite the drastic change in the system's behaviour, observing the transition

can sometimes be subtle. The hallmark of Bose-Einstein condensation (BEC) and

superfluidity in trapped, weakly interacting Bose gases is the sudden

appearance of a dense central core inside a thermal cloud. In strongly

interacting gases, such as the recently observed fermionic superfluids, this

clear separation between the superfluid and the normal parts of the cloud is no

longer given. Condensates of fermion pairs could be detected only using

magnetic field sweeps into the weakly interacting regime. The quantitative

description of these sweeps presents a major theoretical challenge. Here we

demonstrate that the superfluid phase transition can be directly observed by

sudden changes in the shape of the clouds, in complete analogy to the case of

weakly interacting Bose gases. By preparing unequal mixtures of the two spin

components involved in the pairing, we greatly enhance the contrast between the

superfluid core and the normal component. Furthermore, the non-interacting

wings of excess atoms serve as a direct and reliable thermometer. Even in the

normal state, strong interactions significantly deform the density profile of

the majority spin component. We show that it is these interactions which drive

the normal-to-superfluid transition at the critical population imbalance of

70(5)%.

\\ ( http://arXiv.org/abs/cond-mat/0605258 , 751kb)

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Paper: cond-mat/0605261

Date: Wed, 10 May 2006 11:11:16 GMT (32kb)

Title: Transmission of matter wave solitons through nonlinear traps and

barriers

Authors: Josselin Garnier, Fatkhulla Abdullaev

Comments: 6 pages, 4 figures

Subj-class: Other

\\

The transmissions of matter wave solitons through linear and nonlinear

inhomogeneities induced by the spatial variations of the trap and the

scattering length in Bose-Einstein condensates are investigated. New phenomena,

such as the enhanced transmission of a soliton through a linear trap by a

modulation of the scattering length, are exhibited. The theory is based on the

perturbed Inverse Scattering Transform for solitons, and we show that radiation

effects are important. Numerical simulations of the Gross-Pitaevskii equation

confirm the theoretical predictions.

\\ ( http://arXiv.org/abs/cond-mat/0605261 , 32kb)

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Paper: cond-mat/0605271

Date: Wed, 10 May 2006 14:41:57 GMT (291kb)

Title: Non-Linear Beam Splitter in Bose-Einstein Condensate Interferometers

Authors: L. Pezze', A. Smerzi, G.P. Berman, A.R. Bishop, and L.A. Collins

Comments: draft, 19 pages, 10 figures

Subj-class: Materials Science

\\

A beam splitter is an important component of an atomic/optical Mach-Zehnder

interferometer. Here we study a Bose Einstein Condensate beam splitter,

realized with a double well potential of tunable height. We analyze how the

sensitivity of a Mach Zehnder interferometer is degraded by the non-linear

particle-particle interaction during the splitting dynamics. We distinguish

three regimes, Rabi, Josephson and Fock, and associate to them a different

scaling of the phase sensitivity with the total number of particles.

\\ ( http://arXiv.org/abs/cond-mat/0605271 , 291kb)

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Paper: cond-mat/0510624

replaced with revised version Tue, 9 May 2006 22:58:13 GMT (496kb)

Title: The role of interactions, tunneling and harmonic confinement on the

adiabatic loading of bosons in an optical lattice

Authors: Ana Maria Rey, Guido Pupillo, and J. V. Porto

Comments: 9 pages and 6 figures. Two typos in Sec.IIIA were corrected and some

references were updated

Subj-class: Statistical Mechanics

Journal-ref: Phys. Rev. A 73, 023608 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0510624 , 496kb)

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Paper: cond-mat/0511641

replaced with revised version Wed, 10 May 2006 17:18:10 GMT (40kb)

Title: Quantum criticality of a Fermi gas with a spherical dispersion minimum

Authors: Kun Yang and Subir Sachdev

Comments: 4 pages, 1 figure; (v2) added clarifications in response to comments;

(v3) published version with correction to lifetime result

Subj-class: Strongly Correlated Electrons; Superconductivity

Journal-ref: Physical Review Letters 96, 187001 (2006)

DOI: 10.1103/PhysRevLett.96.187001

\\ ( http://arXiv.org/abs/cond-mat/0511641 , 40kb)

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Paper: quant-ph/0604074

replaced with revised version Wed, 10 May 2006 16:50:57 GMT (20kb)

Title: Thermal limitation of far-field matter-wave interference

Authors: Klaus Hornberger

Comments: 8 pages, 2 figures; published version

Journal-ref: Phys. Rev. A 73, 052102 (2006)

DOI: 10.1103/PhysRevA.73.052102

\\ ( http://arXiv.org/abs/quant-ph/0604074 , 20kb)

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Paper: cond-mat/0605283

Date: Wed, 10 May 2006 20:01:45 GMT (543kb)

Title: Matter-wave solitons in radially periodic potentials

Authors: Bakhtiyor B. Baizakov, Boris A. Malomed, and Mario Salerno

Comments: 16 pages, 23 figures

Subj-class: Other

\\

We investigate two-dimensional (2D) states of Bose-Einstein condensates (BEC)

with self-attraction or self-repulsion, trapped in an axially symmetric

optical-lattice potential periodic along the radius. Unlike previously studied

2D models with Bessel lattices, no localized states exist in the linear limit

of the present model, hence all localized states are truly nonlinear ones. We

consider the states trapped in the central potential well, and in remote

circular troughs. In both cases, a new species, in the form of \textit{radial

gap solitons}, are found in the repulsive model (the gap soliton trapped in a

circular trough may additionally support stable dark-soliton pairs). In remote

troughs, stable localized states may assume a ring-like shape, or shrink into

strongly localized solitons. The existence of stable annular states, both

azimuthally uniform and weakly modulated ones, is corroborated by simulations

of the corresponding Gross-Pitaevskii equation. Dynamics of strongly localized

solitons circulating in the troughs is also studied. While the solitons with

sufficiently small velocities are stable, fast solitons gradually decay, due to

the leakage of matter into the adjacent trough under the action of the

centrifugal force. Collisions between solitons are investigated too. Head-on

collisions of in-phase solitons lead to the collapse; $\pi $-out of phase

solitons bounce many times, but eventually merge into a single soliton without

collapsing. The proposed setting may also be realized in terms of spatial

solitons in photonic-crystal fibers with a radial structure.

\\ ( http://arXiv.org/abs/cond-mat/0605283 , 543kb)

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\\

Paper: cond-mat/0605291

Date: Thu, 11 May 2006 06:55:25 GMT (269kb)

Title: Berezinskii-Kosterlitz-Thouless Crossover in a Trapped Atomic Gas

Authors: Zoran Hadzibabic (LKB - Lhomond), Peter Kr\"{u}ger (LKB - Lhomond),

Marc Cheneau (LKB - Lhomond), Baptiste Battelier (LKB - Lhomond), Jean B.

Dalibard (LKB - Lhomond)

Comments: accepted for publication in Nature

Proxy: ccsd ccsd-00067716

Subj-class: Other

\\

Any state of matter is classified according to its order, and the kind of

order a physical system can posses is profoundly affected by its

dimensionality. Conventional long-range order, like in a ferromagnet or a

crystal, is common in three-dimensional (3D) systems at low temperature.

However, in two-dimensional (2D) systems with a continuous symmetry, true

long-range order is destroyed by thermal fluctuations at any finite

temperature. Consequently, in contrast to the 3D case, a uniform 2D fluid of

identical bosons cannot undergo Bose-Einstein condensation. Nevertheless, it

can form a "quasi-condensate" and become superfluid below a finite critical

temperature. The Berezinskii-Kosterlitz-Thouless (BKT) theory associates this

phase transition with the emergence of a topological order, resulting from the

pairing of vortices with opposite circulations. Above the critical temperature,

proliferation of unbound vortices is expected. Here we report the observation

of a BKT-type crossover in a trapped quantum degenerate gas of rubidium atoms.

Using a matter wave heterodyning technique, we observe both the long-wavelength

fluctuations of the quasi-condensate phase and the free vortices. At low

temperatures, the gas is quasi-coherent on the length scale set by the system

size. As the temperature is increased, the loss of long-range coherence

coincides with the onset of proliferation of free vortices. Our results provide

direct experimental evidence for the microscopic mechanism underlying the BKT

theory, and raise new questions regarding coherence and superfluidity in

mesoscopic systems.

\\ ( http://arXiv.org/abs/cond-mat/0605291 , 269kb)

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\\

Paper: cond-mat/0605302

Date: Thu, 11 May 2006 13:49:52 GMT (200kb)

Title: Transport of Atom Packets in a Train of Ioffe-Pritchard Traps

Authors: Thierry Lahaye (LKB - Lhomond), Gael Reinaudi (LKB - Lhomond),

Zhaoying Wang (LKB - Lhomond), Antoine Couvert (LKB - Lhomond), David

Gu\'{e}ry-Odelin (LKB - Lhomond)

Proxy: ccsd ccsd-00068349

Subj-class: Other

\\

We demonstrate transport and evaporative cooling of several atomic clouds in

a chain of magnetic Ioffe-Pritchard traps moving at a low speed ($<1$~m/s). The

trapping scheme relies on the use of a magnetic guide for transverse

confinement and of magnets fixed on a conveyor belt for longitudinal trapping.

This experiment introduces a new approach for parallelizing the production of

Bose-Einstein condensates as well as for the realization of a continuous atom

laser.

\\ ( http://arXiv.org/abs/cond-mat/0605302 , 200kb)

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\\

Paper: cond-mat/0510635

replaced with revised version Thu, 11 May 2006 15:40:57 GMT (609kb)

Title: Integrable models for asymmetric Fermi superfluids: Emergence of a new

exotic pairing phase

Authors: J. Dukelsky, G. Ortiz, S.M.A. Rombouts and K. Van Houcke

Comments: Revised version accepted for publication

Subj-class: Other; Superconductivity

Journal-ref: Phys. Rev. Lett 96, 180404 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0510635 , 609kb)

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\\

Paper: cond-mat/0601184

replaced with revised version Thu, 11 May 2006 01:02:35 GMT (726kb)

Title: Observation of Strong Quantum Depletion in a Gaseous Bose-Einstein

Condensate

Authors: K. Xu, Y. Liu, D.E. Miller, J.K. Chin, W. Setiawan and W. Ketterle

Comments: Replaced with accepted version in PRL

Subj-class: Other

Journal-ref: Phys. Rev. Lett. 96, 180405 (2006)

DOI: 10.1103/PhysRevLett.96.180405

\\ ( http://arXiv.org/abs/cond-mat/0601184 , 726kb)

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\\

Paper: cond-mat/0602278

replaced with revised version Wed, 10 May 2006 20:57:41 GMT (168kb)

Title: Vortex-Peierls States in Optical Lattices

Authors: A.A. Burkov, Eugene Demler

Comments: 4 pages, 4 figures. Published version

Subj-class: Strongly Correlated Electrons; Superconductivity

Journal-ref: Physical Review Letters 96, 180406 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0602278 , 168kb)

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\\

Paper: cond-mat/0604139

replaced with revised version Thu, 11 May 2006 13:44:30 GMT (599kb)

Title: Bose-Fermi Mixtures in a Three-dimensional Optical Lattice

Authors: Kenneth G\"unter, Thilo St\"oferle, Henning Moritz, Michael K\"ohl,

Tilman Esslinger

Subj-class: Strongly Correlated Electrons

Journal-ref: Phys. Rev. Lett. 96, 180402 (2006)

DOI: 10.1103/PhysRevLett.96.180402

\\ ( http://arXiv.org/abs/cond-mat/0604139 , 599kb)

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\\

Paper: physics/0605092

Date: Thu, 11 May 2006 10:07:49 GMT (269kb)

Title: Diffuse reflection of a Bose-Einstein condensate from a rough evanescent

wave mirror

Authors: Helene Perrin, Yves Colombe, Brigitte Mercier, Vincent Lorent, and

Carsten Henkel

Comments: submitted to J Phys B, 10 pages, 6 figures

Subj-class: Atomic Physics; Optics

\\

We present experimental results showing the diffuse reflection of a

Bose-Einstein condensate from a rough mirror, consisting of a dielectric

substrate supporting a blue-detuned evanescent wave. The scattering is

anisotropic, more pronounced in the direction of the surface propagation of the

evanescent wave. These results agree very well with theoretical predictions.

\\ ( http://arXiv.org/abs/physics/0605092 , 269kb)

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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/ -------------------------------------------------------------------------Received on Mon May 15 2006 - 10:28:53 EST

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