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

Date: Tue, 17 Jan 2006 08:44:25 +1000 (EST)

Date: Tue, 17 Jan 2006 08:44:25 +1000 (EST)

This week is only a day late....

Cheers,

Matt.

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Paper: cond-mat/0601103

Date: Thu, 5 Jan 2006 21:49:02 GMT (110kb)

Title: Pomeranchuk and Topological Fermi Surface Instabilities from Central

Interactions

Authors: J. Quintanilla and A. J. Schofield

Comments: 6 pages, 3 figures

Subj-class: Strongly Correlated Electrons; Statistical Mechanics

\\

We address, at the mean field (MF) level, the emergence of a Pomeranchuk

instability (PI) in a uniform Fermi liquid with \emph{central}

particle-particle interactions. We find that a PI with all symmetries, except

$l=1,$ can take place if the interaction is repulsive and has a finite range

$r_{0}$ of the order of the inter-particle distance. We demonstrate this by

solving the MF equations analytically for a simple model interaction. We find,

in addition to the PI, other, subtler phase transitions in which the Fermi

surface changes topology without rotational symmetry-breaking. We argue that

such ``interaction-driven Lifshitz transitions'' may be as generic to such

systems as the PI.

\\ ( http://arXiv.org/abs/cond-mat/0601103 , 110kb)

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Paper: cond-mat/0601109

Date: Fri, 6 Jan 2006 18:50:58 GMT (26kb)

Title: Path Integral Monte Carlo Applied to Nearly Parallel Vortex Filaments

Authors: Timothy Andersen and Chjan Lim

Comments: 17 pages, 5 figures

Subj-class: Statistical Mechanics; Superconductivity

\\

The Nearly Parallel Vortex Filament (NPVF) model has a wide range of

applications from classical fluid turbulence to electron plasmas to superfluids

and Bose-Einstein Condensates. Ceperley's Path Integral Monte Carlo (PIMC)

algorithms provide an excellent tool for calculating the statistics of these

systems in equilibrium, as Sen, Trivedi and Ceperley showed for flux lines of

type-II superconductors by \cite{Sen:2001}. In this poster we discuss our

application of PIMC to NPVF to study the melting of vortex crystals under a

trapping potential when trapping intensity (e.g. angular velocity) increases,

forcing higher vortex densities. We discover a phase transition in which

control of the statistics of containment radius transfers from vortex

interaction in the crystal phase to internal vortex fluctuations in the liquid

phase. At the critical point entropy rather than internal energy becomes the

main factor deciding the system state, consequently the radius becomes chaotic.

We also show that this transition does not exist in the point vortex model.

This work represents the first numerical evidence for the kind of turbulence

occuring at high rotation speed due to vortex tangling. We argue that the

simplified, NPVF model is sufficient to make these assertions and that the full

Biot-Savart law is unnecessary.

\\ ( http://arXiv.org/abs/cond-mat/0601109 , 26kb)

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Paper: cond-mat/0601113

Date: Fri, 6 Jan 2006 07:56:34 GMT (17kb)

Title: Inhomogeneous Hubbard Models: from Weak to Strong Coupling

Authors: Wei-Feng Tsai and Steven A. Kivelson

Comments: 4 pages, 3 figures

Subj-class: Strongly Correlated Electrons; Superconductivity

\\

We present a controlled perturbative approach to the low temperature phase

diagram of highly inhomogeneous Hubbard models in the limit of small coupling,

$t'$, between clusters. We apply this to the dimerized and checkerboard models.

The dimerized model is found to behave like a doped semiconductor, with a

Fermi-liquid groundstate with parameters ({\it e.g.} the effective mass) which

are smooth functions of the Hubbard interaction, $U$. By contrast, the

checkerboard model has a Fermi liquid phase at large $U > U_c = 4.67$, a d-wave

superconducting state with a full gap for $U_c > U > 0$, and a narrow strip of

an intermediate d-wave superconducting phase with gapless ``nodal''

quasiparticles for $|U - U_c| < {\cal O}(t^\prime)$.

\\ ( http://arXiv.org/abs/cond-mat/0601113 , 17kb)

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Paper: cond-mat/0601122

Date: Fri, 6 Jan 2006 15:26:59 GMT (38kb)

Title: Density profile of a polarized unitary Fermi gas

Authors: Fr\'{e}d\'{e}ric Chevy (LKB - Lhomond)

Comments: 4 pages, 3 figures

Proxy: ccsd ccsd-00016604

Subj-class: Statistical Mechanics

\\

We present a theoretical study of the density profile of a trapped strongly

interacting Fermi gas with unbalanced spin populations. Making the assumption

of the existence of a first order phase transition between an unpolarized

superfluid phase and a fully polarized normal phase, we show good agreement

with a recent experiment presented in Partridge et al.

\\ ( http://arXiv.org/abs/cond-mat/0601122 , 38kb)

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Paper: cond-mat/0601125

Date: Fri, 6 Jan 2006 17:39:06 GMT (50kb)

Title: On the free energy within the mean-field approximation

Authors: R. Agra, F. van Wijland, E. Trizac

Comments: pedagogical paper for undergraduate teaching, to appear in Eur. J.

Physics

Subj-class: Statistical Mechanics; Materials Science

\\

We compare two widespread formulations of the mean-field approximation, based

on minimizing an appropriately built mean-field free energy. We use the example

of the antiferromagnetic Ising model to show that one of these formulations

does not guarantee the existence of an underlying variational principle. This

results in a severe failure where straightforward minimization of the

corresponding mean-field free energy leads to incorrect results.

\\ ( http://arXiv.org/abs/cond-mat/0601125 , 50kb)

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Paper: cond-mat/0508645

replaced with revised version Thu, 5 Jan 2006 21:00:48 GMT (31kb)

Title: Potential-energy (BCS) to kinetic-energy (BEC)-driven pairing in the

attractive Hubbard model

Authors: B. Kyung, A. Georges, and A. -M. S. Tremblay

Comments: 4.1 pages, 4 figures

Subj-class: Strongly Correlated Electrons; Superconductivity

\\ ( http://arXiv.org/abs/cond-mat/0508645 , 31kb)

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Paper: cond-mat/0511332

replaced with revised version Fri, 6 Jan 2006 14:21:24 GMT (26kb)

Title: Ground state energy of spin-1/2 fermions in the unitary limit

Authors: Dean Lee (North Carolina State University)

Comments: 17 pages, 9 figures, expanded manuscript includes more data and

cross-checks

Subj-class: Statistical Mechanics

\\ ( http://arXiv.org/abs/cond-mat/0511332 , 26kb)

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Paper: physics/0601036

Date: Fri, 6 Jan 2006 16:23:26 GMT (603kb)

Title: Coherent manipulation of atoms by co-propagating laser beams

Authors: Yuri B. Ovchinnikov

Comments: 19 pages, 12 figures

Subj-class: Atomic Physics

\\

Optical dipole traps and fractional Talbot optical lattices based on the

interference between multiple co-propagating laser beams are proposed. The

variation of relative amplitudes and phases of the interfering light beams of

these traps makes it possible to manipulate the spatial position of trapped

atoms. Examples of spatial translation and splitting of atoms between a set of

the interference traps are considered. The prospect of constructing all-light

atom chips based on the proposed technique is presented.

\\ ( http://arXiv.org/abs/physics/0601036 , 603kb)

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Paper: cond-mat/0601140

Date: Mon, 9 Jan 2006 19:15:59 GMT (7kb)

Title: Relaxation of the molecular state in atomic Fermi gases near a Feshbach

resonance

Authors: V. S. Babichenko

Comments: RevTex4, 4 pages

Subj-class: Other

\\

Relaxation processes in ultra-cold degenerate atomic Fermi gas near a

Feshbach resonance are considered. It is shown that the relaxation rate of the

molecules being in a resonance with the atomic Fermi system is of the order of

the part of the chemical potential defined by the interaction between resonance

molecules. In this connection the lower part of the excitation spectrum of the

system of resonance molecules is not defined well.

\\ ( http://arXiv.org/abs/cond-mat/0601140 , 7kb)

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Paper: cond-mat/0601147

Date: Sun, 8 Jan 2006 16:02:10 GMT (520kb)

Title: LOFF Pairing vs. Breached Pairing in Asymmetric Fermion Superfluids

Authors: Lianyi He, Meng Jin and Pengfei Zhuang

Comments: 14 pages, 18 figures

Subj-class: Superconductivity

\\

A general analysis for the competition between breached pairing and LOFF

pairing mechanisms in asymmetric fermion superfluids is presented in the frame

of a four fermion interaction model in weak coupling region. For the

superfluids with mismatched Fermi surfaces formed in different physical

systems, we analytically and numerically calculated the coupled set of

equations for the gap parameter, pair momentum, and thermodynamic potential.

The breached pairing state is instable due to the Sarma instability or magnetic

instability in any asymmetric system. While the LOFF state is stable only in a

narrow asymmetry window in the case with fixed chemical potentials or fixed

total number and chemical potential difference, it is stable in the whole

coexistence region of breached pairing and LOFF pairing states in the case with

fixed numbers of the two species. The LOFF state can even survive in the highly

asymmetry region where the breached pairing state disappears.

\\ ( http://arXiv.org/abs/cond-mat/0601147 , 520kb)

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Paper: cond-mat/0601148

Date: Sun, 8 Jan 2006 16:25:32 GMT (75kb)

Title: Finite Size Effects in Cold Asymmetrical Fermion Superfluids

Authors: Heron Caldas

Comments: 5 pages, 3 figures (eps)

Subj-class: Superconductivity

\\

We derive the surface energy between the normal and superfluid components of

a mixed phase of a system composed of two particle species with different

densities. The surface energy is obtained by the integration of the free energy

density in the interface between the two phases. We show that the mixed phase

remains as the favored ground state over the gapless phase, even upon the

consideration of the surface energy.

\\ ( http://arXiv.org/abs/cond-mat/0601148 , 75kb)

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Paper: cond-mat/0601151

Date: Sun, 8 Jan 2006 21:18:42 GMT (404kb)

Title: Resonant control of spin dynamics in ultracold quantum gases by

microwave dressing

Authors: Fabrice Gerbier, Artur Widera, Simon Foelling, Olaf Mandel, Immanuel

Bloch

Comments: 4 pages, 5 figures

Subj-class: Other

\\

We study experimentally interaction-driven spin oscillations in optical

lattices in the presence of an off-resonant microwave field. We show that the

energy shift induced by this microwave field can be used to control the spin

oscillations by tuning the system either into resonance to achieve near-unity

contrast or far away from resonance to suppress the oscillations. Finally, we

propose a scheme based on this technique to create a flat sample with either

singly- or doubly-occupied sites, starting from an inhomogeneous Mott

insulator, where singly- and doubly-occupied sites coexist.

\\ ( http://arXiv.org/abs/cond-mat/0601151 , 404kb)

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Paper: cond-mat/0506472

replaced with revised version Sat, 7 Jan 2006 13:17:29 GMT (710kb)

Title: Dynamical stabilization of matter-wave solitons revisited

Authors: Alexander Itin, Shinichi Watanabe, Toru Morishita

Subj-class: Other; Atomic Physics; Chaotic Dynamics

\\ ( http://arXiv.org/abs/cond-mat/0506472 , 710kb)

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Paper: cond-mat/0508063

replaced with revised version Mon, 9 Jan 2006 20:28:10 GMT (33kb)

Title: Bosonization, Pairing, and Superconductivity of the Fermionic

Tonks-Girardeau Gas

Authors: M.D. Girardeau and A. Minguzzi

Comments: v3: 4 pages, 2 figures, revtex4. Section on the fermionic TG gas on a

ring revised, emphasizing degeneracy of ground state for even N and resultant

high sensitivity to external fields. Submitted to PRL

Subj-class: Superconductivity

\\ ( http://arXiv.org/abs/cond-mat/0508063 , 33kb)

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Paper: quant-ph/0601049

Date: Mon, 9 Jan 2006 10:41:54 GMT (89kb)

Title: Atomic reflection off conductor walls as a tool in cold atom traps

Authors: M. Al-Amri and M. Babiker

Comments: article

\\

We explain why a system of cold $^{85}Rb$ atoms at temperatures of the order

$T\approx 7.78\times 10^{-5}$ K and below, but not too low to lie in the

quantum reflection regime, should be automatically repelled from the surface of

a conductor without the need of an evanescent field, as in a typical atom

mirror, to counteract the van der Waals attraction. The repulsive potential

arises naturally outside the conductor and is effective at distances from the

conductor surface of about 400nm, intermediate between the van der Waals and

the Casimir-Polder regions of variation. We propose that such a field-free

reflection capability should be useful as a component in cold atom traps. It

should be practically free of undesirable field fluctuations and would be

operative at distances for which surface roughness, dissipative effects and

other finite conductivity effects should be negligibly small.

\\ ( http://arXiv.org/abs/quant-ph/0601049 , 89kb)

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Paper: quant-ph/0601052

Date: Mon, 9 Jan 2006 19:14:09 GMT (528kb)

Title: Ion Trap in a Semiconductor Chip

Authors: D. Stick, W. K. Hensinger, S. Olmschenk, M. J. Madsen, K. Schwab, and

C. Monroe

Comments: 4 pages, 4 figures

Journal-ref: Nature Phys. 2 (2006) 36-39

\\

The electromagnetic manipulation of isolated atoms has led to many advances

in physics, from laser cooling and Bose-Einstein condensation of cold gases to

the precise quantum control of individual atomic ion. Work on miniaturizing

electromagnetic traps to the micrometer scale promises even higher levels of

control and reliability. Compared with 'chip traps' for confining neutral

atoms, ion traps with similar dimensions and power dissipation offer much

higher confinement forces and allow unparalleled control at the single-atom

level. Moreover, ion microtraps are of great interest in the development of

miniature mass spectrometer arrays, compact atomic clocks, and most notably,

large scale quantum information processors. Here we report the operation of a

micrometer-scale ion trap, fabricated on a monolithic chip using semiconductor

micro-electromechanical systems (MEMS) technology. We confine, laser cool, and

measure heating of a single 111Cd+ ion in an integrated radiofrequency trap

etched from a doped gallium arsenide (GaAs) heterostructure.

\\ ( http://arXiv.org/abs/quant-ph/0601052 , 528kb)

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Paper: cond-mat/0601184

Date: Tue, 10 Jan 2006 02:24:38 GMT (739kb)

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

Subj-class: Other

\\

We studied quantum depletion in a gaseous Bose-Einstein condensate. An

optical lattice enhanced the atomic interactions and modified the dispersion

relation resulting in strong quantum depletion. The depleted fraction was

directly observed as a diffuse background in the time-of-flight images.

Bogoliubov theory provided a semi-quantitative description for our observations

of depleted fractions in excess of 50%.

\\ ( http://arXiv.org/abs/cond-mat/0601184 , 739kb)

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Paper: cond-mat/0601195

Date: Tue, 10 Jan 2006 12:11:14 GMT (910kb)

Title: Applications of density matrices in a trapped Bose gas

Authors: K. Ch. Chatzisavvas, S. E. Massen, Ch. C. Moustakidis, C. P. Panos

Comments: 40 pages, 14 figures, 2 Tables

Subj-class: Other

\\

An overview of the Bose-Einstein condensation of correlated atoms in a trap

is presented by examining the effect of interparticle correlations to one- and

two-body properties of the above systems at zero temperature in the framework

of the lowest order cluster expansion. Analytical expressions for the one- and

two-body properties of the Bose gas are derived using Jastrow-type correlation

function. In addition numerical calculations of the natural orbitals and

natural occupation numbers are also carried out. Special effort is devoted for

the calculation of various quantum information properties including Shannon

entropy, Onicescu informational energy, Kullback-Leibler relative entropy and

the recently proposed Jensen-Shannon divergence entropy. The above quantities

are calculated for the trapped Bose gases by comparing the correlated and

uncorrelated cases as a function of the strength of the short-range

correlations. The Gross-Piatevskii equation is solved giving the density

distributions in position and momentum space, which are employed to calculate

quantum information properties of the Bose gas.

\\ ( http://arXiv.org/abs/cond-mat/0601195 , 910kb)

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Paper: cond-mat/0508624

replaced with revised version Tue, 10 Jan 2006 02:49:26 GMT (212kb)

Title: Kolmogorov Spectrum of Quantum Turbulence

Authors: Michikazu Kobayashi and Makoto Tsubota

Comments: 14pages, 24 figures and 1 table. Appeared in Journal of the Physical

Society of Japan, Vol.74, No.12, p.3248-3258

Subj-class: Other; Statistical Mechanics

Journal-ref: J. Phys. Soc. Jpn 74, 3248 (2005)

\\ ( http://arXiv.org/abs/cond-mat/0508624 , 212kb)

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Paper: quant-ph/0601063

Date: Tue, 10 Jan 2006 17:40:17 GMT (13kb)

Title: Dynamics of Open Bosonic Quantum Systems in Coherent State

Representation

Authors: D.A.R. Dalvit, G.P. Berman, and M. Vishik

Comments: 7 pages

Journal-ref: Phys. Rev. A 73, 013803 (2006)

\\

We consider the problem of decoherence and relaxation of open bosonic quantum

systems from a perspective alternative to the standard master equation or

quantum trajectories approaches. Our method is based on the dynamics of

expectation values of observables evaluated in a coherent state representation.

We examine a model of a quantum nonlinear oscillator with a density-density

interaction with a collection of environmental oscillators at finite

temperature. We derive the exact solution for dynamics of observables and

demonstrate a consistent perturbation approach.

\\ ( http://arXiv.org/abs/quant-ph/0601063 , 13kb)

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Paper: physics/0601054

Date: Mon, 9 Jan 2006 23:01:40 GMT (806kb)

Title: Cold Molecule Spectroscopy for Constraining the Evolution of the Fine

Structure Constant

Authors: Eric R. Hudson, H. J. Lewandowski, Brian C. Sawyer, Jun Ye

Subj-class: Atomic Physics; General Physics

\\

We report precise measurements of ground-state, $\lambda$-doublet microwave

transitions in the hydroxyl radical molecule (OH). Utilizing slow, cold

molecules produced by a Stark decelerator we have improved over the precision

of the previous best measurement by twenty-five-fold for the F' = 2 $\to$ F = 2

transition, yielding (1 667 358 996 $\pm$ 4) Hz, and by ten-fold for the F' = 1

$\to$ F = 1 transition, yielding (1 665 401 803 $\pm$ 12) Hz. Comparing these

laboratory frequencies to those from OH megamasers in interstellar space will

allow a sensitivity of 1 ppm for $\Delta\alpha/\alpha$ over $\sim$$10^{10}$

years.

\\ ( http://arXiv.org/abs/physics/0601054 , 806kb)

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Paper: cond-mat/0601217

Date: Wed, 11 Jan 2006 07:23:32 GMT (878kb)

Title: Two-dimensional solitons in the Gross-Pitaevskii equation with spatially

modulated nonlinearity

Authors: Hidetsugu Sakaguchi and Boris A. Malomed

Comments: 11 pages, 9 figures

Subj-class: Superconductivity; Statistical Mechanics

\\

We introduce a dynamical model of a Bose-Einstein condensate based on the 2D

Gross-Pitaevskii equation, in which the nonlinear coefficient is a function of

radius. The model describes a situation with spatial modulation of the negative

atomic scattering length, via the Feshbach resonance controlled by a properly

shaped magnetic of optical field. We focus on the configuration with the

nonlinear coefficient different from zero in a circle or annulus, including the

case of a narrow ring. Two-dimensional axisymmetric solitons are found in a

numerical form, and also by means of a variational approximation; for an

infinitely narrow ring, the soliton is found in an exact form (in the latter

case, exact solitons are also found in a two-component model). A stability

region for the solitons is identified by means of numerical and analytical

methods. In particular, if the nonlinearity is supported on the annulus, the

upper stability border is determined by azimuthal perturbations; the stability

region disappears if the ratio of the inner and outer radii of the annulus

exceeds a critical value 0.47. The model gives rise to bistability, as the

stationary solitons coexist with stable axisymmetric breathers, whose stability

region extends to higher values of the norm than that of the static solitons.

The collapse threshold strongly increases with the radius of the inner hole of

the annulus. Vortex solitons are found too, but they are unstable.

\\ ( http://arXiv.org/abs/cond-mat/0601217 , 878kb)

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Paper: cond-mat/0601228

Date: Wed, 11 Jan 2006 13:45:46 GMT (38kb)

Title: Small polarons in dilute gas Bose-Einstein condensates

Authors: Fernando M. Cucchietti and Eddy Timmermans

Report-no: LA-UR-06-0083

Subj-class: Other

\\

A neutral impurity atom immersed in a dilute Bose-Einstein condensate (BEC)

can have a bound ground state in which the impurity is self-localized. In this

small polaron-like state, the impurity distorts the density of the surrounding

BEC, thereby creating the self-trapping potential minimum. We describe the

self-localization in a strong coupling approach.

\\ ( http://arXiv.org/abs/cond-mat/0601228 , 38kb)

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Paper: physics/0601073

Date: Wed, 11 Jan 2006 11:55:33 GMT (70kb)

Title: Properties of quasi-one-dimensional molecules with Feshbach resonance

interaction

Authors: V. A. Yurovsky (Tel Aviv University)

Comments: 7 pages, 5 figures

Subj-class: Atomic Physics

\\

Bound states and collisions of atoms with two-channel two-body interactions

in harmonic waveguides are analyzed. The closed-channel contributions to

two-atom bound states become dominant in a case of a weak resonance. At low

energies and values of the non-resonant scattering length the problem can be

approximated by a one-dimensional resonant model. Three-body problem becomes

nonintegrable and properties of three-atomic molecules become different from

ones in the integrable Lieb-Liniger-McGuire model.

\\ ( http://arXiv.org/abs/physics/0601073 , 70kb)

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Paper: cond-mat/0601249

Date: Thu, 12 Jan 2006 09:36:24 GMT (387kb)

Title: Self-trapping of Bose-Einstein condensates in optical lattices

Authors: Bingbing Wang, Panming Fu, Jie Liu, and Biao Wu

Comments: 8 pages, 15 figures

Subj-class: Other

\\

The self-trapping phenomenon of Bose-Einstein condensates (BECs) in optical

lattices is studied extensively by numerically solving the Gross-Pitaevskii

equation. Our numerical results not only reproduce the phenomenon that was

observed in a recent experiment [Anker {\it et al.}, Phys. Rev. Lett. {\bf 94}

(2005)020403], but also find that the self-trapping breaks down at long

evolution times, that is, the self-trapping in optical lattices is only

temporary. The analysis of our numerical results shows that the self-trapping

in optical lattices is related to the self-trapping of BECs in a double-well

potential. A possible mechanism of the formation of steep edges in the wave

packet evolution is explored in terms of the dynamics of relative phases

between neighboring wells.

\\ ( http://arXiv.org/abs/cond-mat/0601249 , 387kb)

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Paper: cond-mat/0601269

Date: Thu, 12 Jan 2006 17:34:28 GMT (78kb)

Title: Phase transitions in the boson-fermion resonance model in one dimension

Authors: Edmond Orignac (ENS-Lyon), Roberta Citro (Salerno)

Comments: 31 pages, 8 EPS figures, RevTeX 4, long version of cond-mat/0505706

Subj-class: Mesoscopic Systems and Quantum Hall Effect; Other

\\

We study 1D fermions with photoassociation or with a narrow Fano-Feshbach

resonance described by the Boson-Fermion resonance model. Using thebosonization

technique, we derive a low-energy Hamiltonian of the system. We show that at

low energy, the order parameters for the Bose Condensation and fermion

superfluidity become identical, while a spin gap and a gap against the

formation of phase slips are formed. As a result of these gaps, charge density

wave correlations decay exponentially in contrast with the phases where only

bosons or only fermions are present. We find a Luther-Emery point where the

phase slips and the spin excitations can be described in terms of

pseudofermions. This allows us to provide closed form expressions of the

density-density correlations and the spectral functions. The spectral functions

of the fermions are gapped, whereas the spectral functions of the bosons remain

gapless. The application of a magnetic field results in a loss of coherence

between the bosons and the fermion and the disappearance of the gap. Changing

the detuning has no effect on the gap until either the fermion or the boson

density is reduced to zero. Finally, we discuss the formation of a Mott

insulating state in a periodic potential. The relevance of our results for

experiments with ultracold atomic gases subject to one-dimensional confinement

is also discussed.

\\ ( http://arXiv.org/abs/cond-mat/0601269 , 78kb)

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Paper: quant-ph/0601079

Date: Thu, 12 Jan 2006 09:03:30 GMT (167kb)

Title: Entanglement of indistinguishable particles in condensed matter physics

Authors: Mark R. Dowling, Andrew C. Doherty and Howard M. Wiseman

Comments: 13 pages, 6 figures, comments welcome

\\

The concept of entanglement in systems where the particles are

indistinguishable has been the subject of much recent interest and controversy.

In this paper we study the notion of entanglement of particles introduced by

Wiseman and Vaccaro [Phys. Rev. Lett. 91, 097902 (2003)] in several specific

physical systems, including some that occur in condensed matter physics. The

entanglement of particles is relevant when the identical particles are

itinerant and so not distinguished by their position as in spin models. We show

that entanglement of particles can behave differently to other approaches that

have been used previously, such as entanglement of modes (occupation-number

entanglement) and the entanglement in the two-spin reduced density matrix. We

argue that the entanglement of particles is what could actually be measured in

most experimental scenarios and thus its physical significance is clear. This

suggests entanglement of particles may be useful in connecting theoretical and

experimental studies of entanglement in strongly-correlated condensed matter

systems.

\\ ( http://arXiv.org/abs/quant-ph/0601079 , 167kb)

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Paper: quant-ph/0601079

Date: Thu, 12 Jan 2006 09:03:30 GMT (167kb)

Title: Entanglement of indistinguishable particles in condensed matter physics

Authors: Mark R. Dowling, Andrew C. Doherty and Howard M. Wiseman

Comments: 13 pages, 6 figures, comments welcome

\\

The concept of entanglement in systems where the particles are

indistinguishable has been the subject of much recent interest and controversy.

In this paper we study the notion of entanglement of particles introduced by

Wiseman and Vaccaro [Phys. Rev. Lett. 91, 097902 (2003)] in several specific

physical systems, including some that occur in condensed matter physics. The

entanglement of particles is relevant when the identical particles are

itinerant and so not distinguished by their position as in spin models. We show

that entanglement of particles can behave differently to other approaches that

have been used previously, such as entanglement of modes (occupation-number

entanglement) and the entanglement in the two-spin reduced density matrix. We

argue that the entanglement of particles is what could actually be measured in

most experimental scenarios and thus its physical significance is clear. This

suggests entanglement of particles may be useful in connecting theoretical and

experimental studies of entanglement in strongly-correlated condensed matter

systems.

\\ ( http://arXiv.org/abs/quant-ph/0601079 , 167kb)

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Paper: quant-ph/0601083

Date: Thu, 12 Jan 2006 17:44:56 GMT (177kb)

Title: Simulating the t-J-U Hamiltonian with atoms in optical lattices

Authors: Alexander Klein and Dieter Jaksch

Comments: 8 pages, 4 figures

\\

We show how the t-J-U Hamiltonian, which is often discussed in the field of

high-temperature superconductivity, can be simulated using ultracold atoms in

optical lattices. For this purpose, previous simulation schemes are extended to

overcome the restriction of a filling factor of exactly one. The time needed to

simulate the Hamiltonian is estimated and the accuracy of the simulation

process is investigated numerically for small systems.

\\ ( http://arXiv.org/abs/quant-ph/0601083 , 177kb)

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Received on Tue Jan 17 2006 - 08:44:25 EST

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