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

Date: Mon, 29 May 2006 10:50:52 +1000 (EST)

Date: Mon, 29 May 2006 10:50:52 +1000 (EST)

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

Home page at:

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

On with the abstracts:

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Paper: cond-mat/0605506

Date: Sun, 21 May 2006 10:10:24 GMT (519kb)

Title: Many-body effects on adiabatic passage through Feshbach resonances

Authors: I. Tikhonenkov, E. Pazy, Y. B. Band, M. Fleischhauer, and A. Vardi

Comments: 9 pages, 9 figures

Subj-class: Other

Journal-ref: Phys. Rev. A 73, 043605 (2006)

\\

We theoretically study the dynamics of an adiabatic sweep through a Feshbach

resonance, thereby converting a degenerate quantum gas of fermionic atoms into

a degenerate quantum gas of bosonic dimers. Our analysis relies on a zero

temperature mean-field theory which accurately accounts for initial molecular

quantum fluctuations, triggering the association process. The structure of the

resulting semiclassical phase space is investigated, highlighting the dynamical

instability of the system towards association, for sufficiently small detuning

from resonance. It is shown that this instability significantly modifies the

finite-rate efficiency of the sweep, transforming the single-pair exponential

Landau-Zener behavior of the remnant fraction of atoms Gamma on sweep rate

alpha, into a power-law dependence as the number of atoms increases. The

obtained nonadiabaticity is determined from the interplay of characteristic

time scales for the motion of adiabatic eigenstates and for fast periodic

motion around them. Critical slowing-down of these precessions near the

instability leads to the power-law dependence. A linear power law $Gamma\propto

alpha$ is obtained when the initial molecular fraction is smaller than the 1/N

quantum fluctuations, and a cubic-root power law $Gamma\propto alpha^{1/3}$ is

attained when it is larger. Our mean-field analysis is confirmed by exact

calculations, using Fock-space expansions. Finally, we fit experimental low

temperature Feshbach sweep data with a power-law dependence. While the

agreement with the experimental data is well within experimental error bars,

similar accuracy can be obtained with an exponential fit, making additional

data highly desirable.

\\ ( http://arXiv.org/abs/cond-mat/0605506 , 519kb)

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Paper: cond-mat/0605507

Date: Sun, 21 May 2006 20:00:01 GMT (768kb)

Title: Fluctuations in Ideal and Interacting Bose-Einstein Condensates: From

the laser phase transition analogy to squeezed states and Bogoliubov

quasiparticles

Authors: Vitaly V. Kocharovsky, Vladimir V. Kocharovsky, Martin Holthaus, C.H.

Raymond Ooi, Anatoly A. Svidzinsky, Wolfgang Ketterle and Marlan O. Scully

Comments: 78 pages, 19 figures, review article

Subj-class: Statistical Mechanics

Journal-ref: Advances in Atomic, Molecular and Optical Physics v. 53, 291

(2006)

\\

We review the phenomenon of equilibrium fluctuations in the number of

condensed atoms in a trap containing N atoms total. We start with a history of

the Bose-Einstein distribution, the Einstein-Uhlenbeck debate concerning the

rounding of the mean number of condensed atoms near a critical temperature, and

a discussion of the relations between statistics of BEC fluctuations in the

grand canonical, canonical, and microcanonical ensembles.

Next we discuss different approaches capable of providing approximate

analytical results and physical insight into the problem of fluctuations. In

particular, we describe the master equation (similar to the quantum theory of

the laser) and canonical-ensemble quasiparticle approaches which give the most

accurate and physically transparent picture of the BEC fluctuations.

In the last part we describe condensate fluctuations in the interacting Bose

gas. In particular, we show that the canonical-ensemble quasiparticle approach

works very well for the interacting gases and yields analytical formulas for

the characteristic function and all moments of the condensate fluctuations. In

most cases the ground-state occupation fluctuations are anomalously large and

are not Gaussian even in the thermodynamic limit. We clarify a crossover

between the ideal and weakly-interacting-gas statistics which is governed by a

pair-correlation squeezing mechanism.

\\ ( http://arXiv.org/abs/cond-mat/0605507 , 768kb)

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Paper: cond-mat/0605508

Date: Sun, 21 May 2006 21:42:00 GMT (190kb)

Title: Inverse Symmetry Breaking in Multi-Scalar Field Theories

Authors: Marcus Benghi Pinto and Rudnei O. Ramos

Comments: 7 pages, 3 figures, talk given at the workshop on Quantum Fields

Under the Influence of External Conditions, QFEXT05, Barcelona, sep-2005

Subj-class: Other

Journal-ref: J. Phys. A39, (2006) 6649-6655

\\

We review how the phenomena of inverse symmetry breaking (and symmetry

nonrestoration) may arise in the context of relativistic as well as

nonrelativistic multi-scalar field theories. We discuss how the consideration

of thermal effects on the couplings produce different transition patterns for

both theories. For the relativistic case, these effects allow the appearance of

inverse symmetry breaking (and symmetry nonrestoration) at arbitrarily large

temperatures. On the other hand, the same phenomena are suppressed in the

nonrelativistic case, which is relevant for condensed matter physics. In this

case, symmetry nonrestoration does not happen while inverse symmetry is allowed

only to be followed by symmetry restoration characterizing a reentrant phase.

The aim of this paper is to give more insight concerning the, qualitatively

correct, results obtained by using one loop perturbation theory in the

evaluation of thermal masses and couplings.

\\ ( http://arXiv.org/abs/cond-mat/0605508 , 190kb)

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Paper: cond-mat/0605509

Date: Mon, 22 May 2006 03:51:56 GMT (68kb)

Title: Spin current and shot noise from a quantum dot coupled to a quantized

cavity field

Authors: Ivana Djuric and Chris P. Search

Subj-class: Other

\\

We examine the spin current and the associated shot noise generated in a

quantum dot connected to normal leads with zero bias voltage across the dot.

The spin current is generated by spin flip transitions induced by a quantized

electromagnetic field inside a cavity with one of the Zeeman states lying below

the Fermi level of the leads and the other above. In the limit of strong

Coulomb blockade, this model is analogous to the Jaynes-Cummings model in

quantum optics. We also calculate the photon current and photon current shot

noise resulting from photons leaking out of the cavity. We show that the photon

current is equal to the spin current and that the spin current can be

significantly larger than for the case of a classical driving field as a result

of cavity losses. In addition to this, the frequency dependent spin (photon)

current shot noise show dips (peaks) that are a result of the discrete nature

of photons.

\\ ( http://arXiv.org/abs/cond-mat/0605509 , 68kb)

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Paper: cond-mat/0605513

Date: Mon, 22 May 2006 09:54:35 GMT (10kb)

Title: Many-body wavefunctions for normal liquid $^3$He

Authors: Markus Holzmann, Bernard Bernu, D. M. Ceperley

Comments: 4 pages

Subj-class: Strongly Correlated Electrons; Statistical Mechanics

\\

We present new trial wave-functions which include 3-body correlations into

the backflow coordinates and a 4-body symmetric potential. We show that our

wavefunctions lower the energy enough to stabilize the ground state energies of

normal liquid $^3$He in the unpolarized state at all pressures in agreement

with experiment; however, quantitative discrepancies remain. Further, we

include strong spin coupling into the Fermi liquid by adapting pairing wave

functions. We demonstrate a new, numerically stable method to evaluate pairing

functions which is also useful for Path Integrals calculations at low, but

non-zero temperatures.

\\ ( http://arXiv.org/abs/cond-mat/0605513 , 10kb)

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Paper: cond-mat/0410287

replaced with revised version Mon, 22 May 2006 13:04:24 GMT (449kb)

Title: The Gross-Pitaevskii equations and beyond for inhomogeneous condensed

bosons

Authors: G. G. N. Angilella, S. Bartalini, F. S. Cataliotti, I. Herrera, N. H.

March, R. Pucci

Comments: To appear in "Trends in Boson Research", edited by A. V. Ling (Nova

Science, New York, ISBN 1594545219). Better quality figures available upon

request

Subj-class: Soft Condensed Matter

\\ ( http://arXiv.org/abs/cond-mat/0410287 , 449kb)

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Paper: quant-ph/0605190

Date: Mon, 22 May 2006 10:54:05 GMT (838kb)

Title: Quantum Computing Using Crossed Atomic Beams

Authors: P. Blythe, B. Varcoe

Comments: 13 pages, 3 figures. PACS: 32.80.Qk, 42.50.Pq, 03.67.Lx

\\

A quantum computer is a hypothetical device in which the laws of quantum

mechanics are used to introduce a degree of parallelism into computations and

which could therefore significantly improve on the computational speed of a

classical computer at certain tasks. Cluster state quantum computing (recently

proposed by Raussendorf and Briegel) is a new paradigm in quantum information

processing and is a departure from the conventional model of quantum

computation. The cluster state quantum computer begins by creating a highly

entangled multi-particle state (the cluster state) which it uses as a quantum

resource during the computation. Information is processed in the computer via

selected measurements on individual qubits that form the cluster state. We

describe in detail how a scalable quantum computer can be constructed using

microwave cavity QED and, in a departure from the traditional understanding of

a computer as a fixed array of computational elements, we show that cluster

state quantum computing is well suited to atomic beam experiments. We show that

all of the necessary elements have been individually realised, and that the

construction of a truly scalable atomic beam quantum computer may be an

experimental reality in the near future.

\\ ( http://arXiv.org/abs/quant-ph/0605190 , 838kb)

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Paper: quant-ph/0605191

Date: Mon, 22 May 2006 12:06:26 GMT (146kb)

Title: Atomic entanglement mediated by a squeezed cavity field

Authors: Biplab Ghosh, A. S. Majumdar, N. Nayak

Comments: 6 pages, 7 eps figures

\\

We consider the coherent state radiation field inside a micromaser cavity and

study the entanglement mediated by it on a pair of two level atoms passing

though the cavity one after the other. We then investigate the effects of

squeezing of the cavity field on the atomic entanglement. We compute the

entanglement of formation for the emerging mixed two-atom state and show that

squeezing of the cavity radiation field can increase the atomic entanglement.

\\ ( http://arXiv.org/abs/quant-ph/0605191 , 146kb)

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Paper: physics/0605176

Date: Mon, 22 May 2006 15:56:17 GMT (284kb)

Title: Phase-dependent light propagation in atomic vapors

Authors: S. Kajari-Schroeder, G. Morigi, S. Franke-Arnold and G.-L. Oppo

Comments: 16 pages, 11 figures

Subj-class: Atomic Physics

\\

Light propagation in an atomic medium whose coupled electronic levels form a

diamond-configuration exhibits a critical dependence on the input conditions.

In particular, the relative phase of the input fields gives rise to

interference phenomena in the electronic excitation whose interplay with

relaxation processes determines the stationary state. We integrate numerically

the Maxwell-Bloch equations and observe two metastable behaviors for the

relative phase of the propagating fields corresponding to two possible

interference phenomena. These phenomena are associated to separate types of

response along propagation, minimize dissipation, and are due to atomic

coherence. These behaviors could be studied in gases of isotopes of

alkali-earth atoms with zero nuclear spin, and offer new perspectives in

control techniques in quantum electronics.

\\ ( http://arXiv.org/abs/physics/0605176 , 284kb)

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Paper : cond-mat/0506415

replaced with revised version Tue, 23 May 2006 18:36:54 GMT (74kb)

Title: Cold Atom Optical Lattices as Quantum Analog Simulators for Aperiodic

One-Dimensional Localization Without Disorder

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

Subj-class: Other; Atomic Physics

Journal-ref: Phys. Rev. A 73, 041609(R) (2006)

\\ ( http://arXiv.org/abs/cond-mat/0506415 , 74kb)

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Paper: cond-mat/0605550

Date: Tue, 23 May 2006 03:42:20 GMT (127kb)

Title: Fermion nodes and nodal cells of noninteracting and interacting fermions

Authors: Lubos Mitas

Comments: 17 pages, 10 figures

Subj-class: Other; Strongly Correlated Electrons

\\

A fermion node is subset of fermionic configurations for which a real wave

function vanishes due to the antisymmetry and the node divides the

configurations space into compact nodal cells (domains). We analyze the

properties of fermion nodes of fermionic ground state wave functions for a

number of systems. For several models we demonstrate that noninteracting

spin-polarized fermions in dimension two and higher have closed-shell ground

state wave functions with the minimal two nodal cells for any system size and

we formulate a theorem which sumarizes this result. The models include periodic

fermion gas, fermions on the surface of a sphere, fermions in a box. We prove

the same property for atomic states with up to 3d half-filled shells. Under

rather general assumptions we then derive that the same is true for unpolarized

systems with arbitrarily weak interactions using Bardeen-Cooper-Schrieffer

(BCS) variational wave function. We further show that pair correlations

included in the BCS wave function enable singlet pairs of particles to wind

around the periodic box without crossing the node pointing towards the

relationship of nodes to transport and many-body phases such as

superconductivity. Finally, we point out that the arguments extend also to

fermionic temperature dependent/imaginary-time density matrices. The results

reveal fundamental properties of fermion nodal structures and provide new

insights for accurate constructions of wave functions and density matrices in

quantum and path integral Monte Carlo methods.

\\ ( http://arXiv.org/abs/cond-mat/0605550 , 127kb)

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Paper: cond-mat/0605554

Date: Tue, 23 May 2006 09:22:27 GMT (52kb)

Title: Dark stationary matter-waves via parity-selective evaporation in a

Tonks-Girardeau gas

Authors: H. Buljan, O. Manela, R. Pezer, A. Vardi, and M. Segev

Comments: 4 pages, 1 figure

Subj-class: Other

\\

We propose a scheme for observing dark stationary waves in a Tonks-Girardeau

(TG) gas. The scheme is based on parity-selective dynamical "evaporation" of

the gas via a time-dependent potential, which excites the gas from its ground

state towards a desired specially-tailored many-body state. These excitations

of the TG gas are analogous to linear partially coherent nondiffracting beams

in optics, as evident from the mapping between the quantum dynamics of the TG

gas and the propagation of incoherent light in one-dimensional linear photonic

structures.

\\ ( http://arXiv.org/abs/cond-mat/0605554 , 52kb)

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Paper: cond-mat/0605571

Date: Tue, 23 May 2006 13:19:44 GMT (36kb)

Title: Phases of the polar spin-1 Bose gas in magnetic field

Authors: Krisztian Kis-Szabo, Peter Szepfalusy, Gergely Szirmai

Comments: 5 pages, 1 figure

Subj-class: Other

\\

We study different properties of the phases originating from the polar phase

of a Bose--Einstein condensed spin-1 gas when a magnetic field is switched on.

Within the Green's function approach generalized Hugenholtz--Pines theorems are

presented, which ensure the existence of gapless Goldstone modes, whose number

is shown to reflect the number of independent phase fluctuations of the complex

order parameter. Crossover to a quantum phase transition when the temperature

goes to zero is also studied. Detailed calculations are presented in a

generalized mean field approximation.

\\ ( http://arXiv.org/abs/cond-mat/0605571 , 36kb)

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Paper: cond-mat/0506371

replaced with revised version Tue, 23 May 2006 14:46:05 GMT (134kb)

Title: Localization of Matter Waves in 2D-Disordered Optical Potentials

Authors: R. C. Kuhn, C. Miniatura, D. Delande, O. Sigwarth and C. A. Mueller

Comments: 4 pages, 3 figures, figures changed, references updated

Subj-class: Mesoscopic Systems and Quantum Hall Effect

Journal-ref: Phys. Rev. Lett. 95, 250403 (2005)

DOI: 10.1103/PhysRevLett.95.250403

\\ ( http://arXiv.org/abs/cond-mat/0506371 , 134kb)

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Paper: cond-mat/0512243

replaced with revised version Tue, 23 May 2006 13:20:09 GMT (217kb)

Title: Phase diagram of Bose-Fermi mixtures in one-dimensional optical lattices

Authors: Lode Pollet, Matthias Troyer, Kris Van Houcke, Stefan M. A. Rombouts

Comments: 5 pages, 5 figures, replaced with published version

Subj-class: Statistical Mechanics

Journal-ref: Phys. Rev. Lett. 96, 190402 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0512243 , 217kb)

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Paper: cond-mat/0603332

replaced with revised version Tue, 23 May 2006 00:21:00 GMT (410kb)

Title: Mean field phase diagrams of imbalanced Fermi gases near a Feshbach

resonance

Authors: Hui Hu and Xia-Ji Liu

Comments: 4 pages + 5 figures, references updated, Published verison in Phys.

Rev. A as a Rapid Communication

Subj-class: Strongly Correlated Electrons; Superconductivity

Journal-ref: Phys. Rev. A 73, 051603 (R) (2006)

DOI: 10.1103/PhysRevA.73.051603

\\ ( http://arXiv.org/abs/cond-mat/0603332 , 410kb)

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Paper: cond-mat/0603571

replaced with revised version Tue, 23 May 2006 16:01:22 GMT (90kb)

Title: Identifying the Bose glass phase

Authors: R. Pugatch, N. Bar-gill, N. Katz, E. Rowen, N. Davidson

Comments: 4 pages, 3 figures (corrected and expanded bibliography)

Subj-class: Soft Condensed Matter; Other

\\ ( http://arXiv.org/abs/cond-mat/0603571 , 90kb)

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Paper: cond-mat/0605102

replaced with revised version Tue, 23 May 2006 16:45:14 GMT (243kb)

Title: Topological defects and the superfluid transition of the $s=1$ spinor

condensate in two dimensions

Authors: Subroto Mukerjee, Cenke Xu, and J. E. Moore

Comments: 4 pages, 2 figures; corrected references

Subj-class: Other

\\ ( http://arXiv.org/abs/cond-mat/0605102 , 243kb)

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Paper: physics/0605200

Date: Tue, 23 May 2006 17:01:52 GMT (401kb)

Title: An accurate optical lattice clock with 87Sr atoms

Authors: Rodolphe Le Targat (SYRTE), Xavier Baillard (SYRTE), Mathilde

Fouch\'{e} (SYRTE), Anders Brusch (SYRTE), Olivier Tcherbakoff (SYRTE),

Giovanni D. Rovera (SYRTE), Pierre Lemonde (SYRTE)

Proxy: ccsd ccsd-00071833

Subj-class: Atomic Physics

\\

We report a frequency measurement of the 1S0-3P0 transition of 87Sr atoms in

an optical lattice clock. The frequency is determined to be 429 228 004 229 879

(5) Hz with a fractional uncertainty that is comparable to state-of-the-art

optical clocks with neutral atoms in free fall. Two previous measurements of

this transition were found to disagree by about 2x10^{-13}, i.e. almost four

times the combined error bar, instilling doubt on the potential of optical

lattice clocks to perform at a high accuracy level. In perfect agreement with

one of these two values, our measurement essentially dissipates this doubt.

\\ ( http://arXiv.org/abs/physics/0605200 , 401kb)

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Paper: cond-mat/0605581

Date: Tue, 23 May 2006 21:08:29 GMT (23kb)

Title: Response to Comment on "Pairing and Phase Separation in a Polarized

Fermi Gas"

Authors: Guthrie B. Partridge, Wenhui Li, Ramsey I. Kamar, Yean-An Liao, and

Randall G. Hulet

Comments: This is a response to version 1 of the Comment (cond-mat/0603489 v1).

This version of the Comment was submitted to and rejected by Science

Subj-class: Superconductivity; Strongly Correlated Electrons

\\

In their comment, Zwierlein and Ketterle contend that features observed in

real-space distributions recorded in our experiment are an artifact of an

anharmonic trapping potential. We show that Zwierlein and Ketterle have grossly

overestimated these effects, and that anharmonicities can neither

quantitatively nor qualitatively reproduce the observed distributions.

\\ ( http://arXiv.org/abs/cond-mat/0605581 , 23kb)

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Paper: cond-mat/0605597

Date: Wed, 24 May 2006 13:01:29 GMT (95kb)

Title: Classical simulation of infinite-size quantum lattice systems in one

spatial dimension

Authors: G. Vidal

Comments: 5 pages, 6 figures

Subj-class: Strongly Correlated Electrons

\\

We show how translational invariance can be exploited to efficiently simulate

one-dimensional quantum lattice systems in the limit of an infinite lattice.

Both the computation of the ground state and the simulation of time evolution

are considered.

\\ ( http://arXiv.org/abs/cond-mat/0605597 , 95kb)

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Paper: cond-mat/0605603

Date: Wed, 24 May 2006 15:09:19 GMT (5kb)

Title: Finite time collapse of N classical fields described by coupled

nonlinear Schrodinger equations

Authors: D. C. Roberts and A. C. Newell

Comments: 3 pages

Subj-class: Other

\\

We prove the finite-time collapse of a system of N classical fields, which

are described by N coupled nonlinear Schrodinger equations. We derive the

conditions under which all of the fields experiences this finite-time collapse.

Finally, for two-dimensional systems, we derive constraints on the number of

particles associated with each field that are necessary to prevent collapse.

\\ ( http://arXiv.org/abs/cond-mat/0605603 , 5kb)

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Paper: cond-mat/0605604

Date: Wed, 24 May 2006 15:14:29 GMT (61kb)

Title: pi-Josephson junction and spontaneous superflow in rings from ultracold

fermionic gases

Authors: Miodrag Kulic

Comments: 6 pages, 3 figures

Subj-class: Statistical Mechanics; Strongly Correlated Electrons

\\

The BCS like pairing in ultracold fermionic gases is studied in the model of

"isotopic-spin" pairing which is proposed in 1991. This model assumes a

mismatch $\delta $ in energies (chemical potentials) of pairing fermionic

atoms. In case when $\delta >\delta_{c1}$ at T=0 $K$, and $\delta >\delta

^{\ast}$ at $T<T^{\ast}$, the nonuniform (LOFF-like) superfluid state is

realized with the oscillating order parameter. It is shown that the $\pi

$-Josephson junction can be realized in $SMS$ systems, where the left and right

banks $S$ are neutral ultracold fermionic superfluids. The weak link $M$ is

made from the normal ultracold fermionic gas (also neutral) with the finite

mismatch $\delta $. If such a $\pi $% -junction is a part of the closed ring

there is a spontaneous breaking of time-reversal symmetry and spontaneous

superfluid mass-current flows in the ring. This is realized if the radius of

the ring $R$ is larger than the critical one $R_{c}$. All these effects exist

also in the case when $\delta \gg \Delta $, where $\Delta $ is the superfluid

gap, but with the reduced thickness of the weak link.

It is discussed also, that if junctions such as $SM_{1}M_{2}S$ and trilayers

$% M_{1}SM_{2}$ are realizable in ultracold fermionic atomic gases, they could

open a way for a new kind of electronics - \textit{hypertronics}.

\\ ( http://arXiv.org/abs/cond-mat/0605604 , 61kb)

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Paper: cond-mat/0605607

Date: Wed, 24 May 2006 18:31:34 GMT (217kb)

Title: A superfluid 4He interferometer operating near 2 K

Authors: Emile Hoskinson, Yuki Sato, and Richard Packard

Comments: 8 pages, 2 figures

Subj-class: Superconductivity

\\

Matter-wave interferometers reveal some of the most fascinating phenomena of

the quantum world. Phase shifts due to rotation (the Sagnac effect) for

neutrons, free atoms and superfluid 3He reveal the connection of matter waves

to a non-rotating inertial frame. In addition, phase shifts in electron waves

due to magnetic vector potentials (the Aharonov-Bohm effect) show that physical

states can be modified in the absence of classical forces. We report here the

observation of interference induced by the Earth's rotation in superfluid 4He

at 2 K, a temperature 2000 times higher than previously achieved with 3He. This

interferometer, an analog of a dc-SQUID, employs a recently reported phenomenon

wherein superfluid 4He exhibits quantum oscillations in an array of sub-micron

apertures. We find that the interference pattern persists not only when the

aperture array current-phase relation is a sinusoidal function characteristic

of the Josephson effect, but also at lower temperatures where it is linear and

oscillations occur by phase slips. The modest requirements for the

interferometer (2 K cryogenics and fabrication of apertures at the level of

100nm) and its potential resolution suggest that, when engineering challenges

such as vibration isolation are met, superfluid 4He interferometers could

become important scientific probes.

\\ ( http://arXiv.org/abs/cond-mat/0605607 , 217kb)

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Paper: cond-mat/0508195

replaced with revised version Wed, 24 May 2006 16:08:04 GMT (93kb)

Title: Velocity of vortices in inhomogeneous Bose-Einstein condensates

Authors: Halvor M. Nilsen, Gordon Baym, and C. J. Pethick

Comments: 5 pages, one .eps figure. Published version

Report-no: NORDITA-2005-51

Subj-class: Other

Journal-ref: Proc. Natl. Acad. Sci. 103, 7978 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0508195 , 93kb)

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Paper: cond-mat/0510750

replaced with revised version Wed, 24 May 2006 10:30:54 GMT (34kb)

Title: Explicit expressions for the topological defects of spinor Bose-Einstein

condensates

Authors: H. M\"akel\"a

Comments: 17 pages, partly rewritten to improve clarity, conclusions unchanged

Subj-class: Other

Journal-ref: J. Phys. A: Math. Gen. 39, 7423 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0510750 , 34kb)

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Paper: cond-mat/0601681

replaced with revised version Wed, 24 May 2006 17:18:29 GMT (226kb)

Title: Exact Study of the 1D Boson Hubbard Model with a Superlattice Potential

Authors: V.G. Rousseau, D.P. Arovas M. Rigol, F. H\'ebert, G.G. Batrouni, R.T.

Scalettar

Comments: 12 pages, 22 figures

Subj-class: Other; Strongly Correlated Electrons

Journal-ref: Physical Review B 73, 174516 (2006)

DOI: 10.1103/PhysRevB.73.174516

\\ ( http://arXiv.org/abs/cond-mat/0601681 , 226kb)

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Paper: cond-mat/0603498

replaced with revised version Wed, 24 May 2006 06:00:43 GMT (682kb)

Title: Pairing in a three component Fermi gas

Authors: T. Paananen, J.-P. Martikainen, and P. Torma

Comments: 10 pages, 3 figures

Subj-class: Superconductivity

Journal-ref: Phys. Rev. A 73, 053606 (2006)

\\ ( http://arXiv.org/abs/cond-mat/0603498 , 682kb)

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Paper: cond-mat/0604232

replaced with revised version Wed, 24 May 2006 09:39:08 GMT (346kb)

Title: Three-dimensional strong localization of matter waves by scattering from

atoms in a lattice with a confinement-induced resonance

Authors: Pietro Massignan (LKB - Lhomond), Yvan Castin (LKB - Lhomond)

Comments: 21 pages; 14 figures

Proxy: ccsd ccsd-00022452

Subj-class: Disordered Systems and Neural Networks

\\ ( http://arXiv.org/abs/cond-mat/0604232 , 346kb)

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Paper: quant-ph/0605202

Date: Tue, 23 May 2006 22:37:44 GMT (21kb)

Title: Adiabatic Condition for Nonlinear Systems

Authors: Han Pu, Peter Maenner, Weiping Zhang, and Hong Y. Ling

Comments: 4 pages, 3 figures

\\

We revisit the adiabatic criterion in stimulated Raman adiabatic passage for

the three-level $\Lambda$-system, and compare the situation with and without

nonlinearity. In linear systems, the adiabatic condition is derived with the

help of the instantaneous eigenvalues and eigenstates of the Hamiltonian, a

procedure that breaks down in the presence of nonlinearity. Using an explicit

example relevant to photoassociation of atoms into diatomic molecules, we

demonstrate that the proper way to derive the adiabatic condition for the

nonlinear systems is through a linearization procedure.

\\ ( http://arXiv.org/abs/quant-ph/0605202 , 21kb)

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Paper: quant-ph/0605210

Date: Wed, 24 May 2006 14:20:11 GMT (390kb)

Title: Ultracold Few-Boson Systems in a Double-Well Trap

Authors: Sascha Z\"ollner, Hans-Dieter Meyer, and Peter Schmelcher

\\

We investigate the transition of a quasi-one-dimensional few-boson system

from a weakly correlated to a fragmented and finally a fermionized ground

state. Our numerically exact analysis, based on a multi-configurational method,

explores the interplay between different shapes of external and inter-particle

forces. Specifically, we demonstrate that the addition of a central barrier to

an otherwise harmonic trap may supports the system's fragmentation, with a

symmetry-induced distinction between even and odd atom numbers. Moreover, the

impact of inhomogeneous interactions is studied, where the effective coupling

strength is spatially modulated. It is laid out how the ground state can be

displaced in a controlled way depending on the trap and the degree of

modulation. We present the one- and two-body densities and, beyond that,

highlight the role of correlations on the basis of the natural occupations.

\\ ( http://arXiv.org/abs/quant-ph/0605210 , 390kb)

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\\

Paper: cond-mat/0605616

Date: Thu, 25 May 2006 01:25:22 GMT (61kb)

Title: Pi-Josephson junction and spontaneous superflow in rings from ultracold

fermionic atomic gases

Authors: Miodrag L. Kulic

Comments: 6 pages, 3 figures

Subj-class: Superconductivity; Soft Condensed Matter

\\

The BCS like pairing in ultracold fermionic gases is studied in the model of

"isotopic-spin" pairing which is proposed in 1991 by the present author and his

collaborator. This model assumes a mismatch \delta in energies (chemical

potentials) of pairing fermionic atoms. In case when \delta >\delta_{c1} at T=0

K, and \delta >\delta ^{\ast} at T<T^{\ast}, the nonuniform (LOFF-like)

superfluid state is realized with the oscillating order parameter. It is shown

that the pi-Josephson junction can be realized in SMS systems, where the left

and right banks S are neutral ultracold fermionic superfluids. The weak link

$M$ is made from the normal ultracold fermionic gas (also neutral) with the

finite mismatch \delta. If such a pi-junction is a part of the closed ring

there is a spontaneous breaking of time-reversal symmetry and spontaneous

superfluid mass-current flows in the ring. This is realized if the radius of

the ring R is larger than the critical one R_{c}. All these effects exist also

in the case when \delta >>\Delta, where \Delta is the superfluid gap, but with

the reduced thickness of the weak link.

It is discussed also, that if junctions such as SM_{1}M_{2}S and trilayers

M_{1}SM_{2} are realizable in ultracold fermionic atomic gases, they could open

a way for a new kind of electronics - hypertronics.

\\ ( http://arXiv.org/abs/cond-mat/0605616 , 61kb)

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\\

Paper: cond-mat/0605622

Date: Thu, 25 May 2006 09:30:53 GMT (261kb)

Title: Discrete breathers in BEC with two- and three-body interactions in

optical lattice

Authors: F.Kh. Abdullaev, A. Bouketir, A. Messikh, B.A. Umarov

Comments: 10 pages, 10 figures

Subj-class: Other

\\

We investigate the properties of discrete breathers in a Bose-Einstein

condensate with two- and three-body interactions in optical lattice. In the

tight-binding approximation the Gross-Pitaevskii equation with periodic

potential for the condensate wavefunction is reduced to the cubic-quintic

discrete nonlinear Schr\"odinger equation. We analyze the regions of

modulational instabilities of nonlinear plane waves. This result is important

to obtain the conditions for generation of discrete solitons(breathers) in

optical lattice. Also using the Page approach, we derive the conditions for the

existence and stability for bright discrete breather solutions. It is shown

that the quintic nonlinearity brings qualitatively new conditions for stability

of strongly localized modes. The numerical simulations conform with the

analytical predictions.

\\ ( http://arXiv.org/abs/cond-mat/0605622 , 261kb)

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\\

Paper: physics/0605225

Date: Thu, 25 May 2006 15:27:16 GMT (70kb)

Title: Worm Algorithm and Diagrammatic Monte Carlo: A New Approach to

Continuous-Space Path Integral Monte Carlo Simulations

Authors: M. Boninsegni, N. V. Prokof'ev and B. V. Svistunov

Comments: 17 pages, 13 figures

Subj-class: Computational Physics

\\

A detailed description is provided of a new Worm Algorithm, enabling the

accurate computation of thermodynamic properties of quantum many-body systems

in continuous space, at finite temperature. The algorithm is formulated within

the general Path Integral Monte Carlo (PIMC) scheme, but also allows one to

perform quantum simulations in the grand canonical ensemble, as well as to

compute off-diagonal imaginary-time correlation functions, such as the

Matsubara Green function, simultaneously with diagonal observables. Another

important innovation consists of the expansion of the attractive part of the

pairwise potential energy into elementary (diagrammatic) contributions, which

are then statistically sampled. This affords a complete microscopic account of

the long-range part of the potential energy, while keeping the computational

complexity of all updates independent of the size of the simulated system. The

computational scheme allows for efficient calculations of the superfluid

fraction and off-diagonal correlations in space-time, for system sizes which

are orders of magnitude larger than those accessible to conventional PIMC. We

present illustrative results for the superfluid transition in bulk liquid

helium-four in two and three dimensions, as well as the calculation of the

chemical potential of solid helium-four.

\\ ( http://arXiv.org/abs/physics/0605225 , 70kb)

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\\

Paper: physics/0509157

replaced with revised version Thu, 25 May 2006 17:10:31 GMT (132kb)

Title: Polarization spectroscopy in rubidium and cesium

Authors: M. L. Harris, C. S. Adams, S. L. Cornish, I. C. McLeod, E. Tarleton

and I. G. Hughes

Comments: 8 pages, 5 figures, to be published in Phys. Rev. A; figures and

discussion added

Subj-class: Atomic Physics

\\ ( http://arXiv.org/abs/physics/0509157 , 132kb)

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Till next week,

Matt.

-- ------------------------------------------------------------------------- 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 29 2006 - 10:50:52 EST

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