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

Date: Wed, 3 May 2006 08:47:24 +1000 (EST)

Date: Wed, 3 May 2006 08:47:24 +1000 (EST)

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

Hi all,

My apologies for the delay this week ... all arXiv submissions up until

yesterday are included.

BTW - I am slightly paranoid that I might miss the odd abstract here and there.

If you think I have missed something of interest to the community, please let me

know and I will include it in the following week.

Cheers,

Matt.

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Paper: cond-mat/0604495

Date: Thu, 20 Apr 2006 21:14:28 GMT (18kb)

Title: Magnetic phase diagram of a frustrated ferrimagnetic ladder: Relation to

the one-dimensional boson Hubbard model

Authors: N. B. Ivanov and J. Richter

Comments: 4 pages, 2 figures

Subj-class: Strongly Correlated Electrons

Journal-ref: Phys. Rev. B 73, 132407 (2006)

DOI: 10.1103/PhysRevB.73.132407

\\

We study the magnetic phase diagram of two coupled mixed-spin $(1,{1/2})$

Heisenberg chains as a function of the frustration parameter related to

diagonal exchange couplings. The analysis is performed by using spin-wave

series and exact numerical diagonalization techniques. The obtained phase

diagram--containing the Luttinger liquid phase, the plateau phase with a

magnetization per rung $M=1/2$, and the fully polarized phase--is closely

related to the generic $(J/U,\mu/U)$ phase diagram of the one-dimensional boson

Hubbard model.

\\ ( http://arXiv.org/abs/cond-mat/0604495 , 18kb)

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Paper: cond-mat/0604500

Date: Fri, 21 Apr 2006 19:45:56 GMT (88kb)

Title: An epsilon expansion for Fermi gas at infinite scattering length

Authors: Yusuke Nishida and Dam Thanh Son

Comments: 4 pages, 4 figures, revtex4

Report-no: INT-PUB 06-08, TKYNT-06-06

Subj-class: Other

\\

We show that there exists a systematic expansion around four spatial

dimensions for Fermi gas in the unitarity regime. We perform the calculations

to leading and next-to-leading orders in the expansion over epsilon=4-d, where

d is the dimensionality of space. We find the ratio of chemical potential and

Fermi energy to be mu/epsilon_F=1/2 epsilon^3/2 + 1/16 epsilon^5/2 ln epsilon

-0.0246 epsilon^5/2 and the ratio of the gap in the fermion quasiparticle

spectrum and the chemical potential to be Delta/mu=2/epsilon-0.691. The minimum

of the fermion dispersion curve is located at |p|=(2m epsilon_0)^1/2 where

epsilon_0/mu=2+O(epsilon). Extrapolation to d=3 gives results consistent with

Monte Carlo simulations.

\\ ( http://arXiv.org/abs/cond-mat/0604500 , 88kb)

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Paper: cond-mat/0604505

Date: Fri, 21 Apr 2006 08:16:45 GMT (106kb)

Title: Cyclic phase in F=2 spinor condensate: long-range order, kinks, and

roughening transition

Authors: W. V. Pogosov, K. Machida

Comments: 6 pages, 1 figure

Subj-class: Statistical Mechanics

\\

We study the effect of thermal fluctuations on homogeneous infinite

Bose-Einstein condensate with spin F=2 in the cyclic state, when atoms occupy

three hyperfine states with $m_{F}=0, \pm 2$. We use both the approach of

small-amplitude oscillations and mapping of our model on the sine-Gordon model.

We show that thermal fluctuations lead to the existence of the rough phase in

one- and two-dimensional systems, when presence of kinks is favorable. The

structure and energy of a single kink are found. We also discuss the effect of

thermal fluctuations on spin degrees of freedom in F=1 condensate.

\\ ( http://arXiv.org/abs/cond-mat/0604505 , 106kb)

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Paper: cond-mat/0604509

Date: Fri, 21 Apr 2006 10:19:26 GMT (121kb)

Title: Bose-Einstein Condensation Picture of Superconductivity in High

Temperature Superconductors (Dilute Metals)

Authors: V.N.Bogomolov

Comments: 5 pages, 5 figures

Subj-class: Superconductivity

\\

Structures and parameters of some high and low temperature superconductors

(HTSC, LTSC) are considered basing on the alternative estimate of the O2- ion

radius magnitude (0.5-0.6) A. Phase transitions into the superconducting state

are considered as the Bose-Einstein condensation (BEC). The super HTSC with Tc

= 371 K (YBa2Cu3Se7) and TC ~ 400K (Ag2(Ag3Pb2H2O6)) and LTSC with Tc~0.3K

(SrNbxTi(1-x)O3) are shown to be of the BEC type. Instability of the structure

of the first one results from higher magnitude of the Se2- ion radius in

comparison with the O2- radius. The second one forms quasi one-dimensional

structures and is rather inpractical. The electron density and the effective

mass are estimated for some stoichiometric and non-stoichiometric

(nano-composite) high temperature superconductors, which have some peculiar

features. Large effective masses can indicate existance of polarons

(bipolarons) in such systems. Some new superconductors MgxWO3.

\\ ( http://arXiv.org/abs/cond-mat/0604509 , 121kb)

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Paper (*cross-listing*): nlin.PS/0604044

Date: Thu, 20 Apr 2006 16:03:24 GMT (151kb)

Title: Oblique spatial dark solitons in supersonic flow of Bose-Einstein

condensate

Authors: G.A. El, A. Gammal, A.M. Kamchatnov

Comments: 4 pages, 3 figures

Subj-class: Pattern Formation and Solitons; Soft Condensed Matter

\\

In framework of the Gross-Pitaevskii mean field approach it is shown that

supersonic flow of Bose-Einstein condensate can support a new type of

pattern--an oblique spatial dark soliton. Exact spatial dark soliton solution

of the Gross-Pitaevskii equation is obtained. It is demonstrated by numerical

simulations that spatial solitons can be generated by an obstacle inserted into

the flow. Connection of the developed theory with available experimental data

is discussed.

\\ ( http://arXiv.org/abs/nlin/0604044 , 151kb)

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Paper: quant-ph/0604158

Date: Thu, 20 Apr 2006 21:06:08 GMT (846kb)

Title: Semiclassical approach to Bose-Einstein condensates in a triple well

potential

Authors: S. Mossmann, C. Jung

Comments: 15 pages, 15 figures

\\

We present a new approach for the analysis of Bose-Einstein condensates in a

few mode approximation. This method has already been used to successfully

analyze the vibrational modes in various molecular systems and offers a new

perspective on the dynamics in many particle bosonic systems. We discuss a

system consisting of a Bose-Einstein condensate in a triple well potential.

Such systems correspond to classical Hamiltonian systems with three degrees of

freedom. The semiclassical approach allows a simple visualization of the

eigenstates of the quantum system referring to the underlying classical

dynamics. From this classification we can read off the dynamical properties of

the eigenstates such as particle exchange between the wells and entanglement

without further calculations. In addition, this approach offers new insights

into the validity of the mean-field description of the many particle system by

the Gross-Pitaevskii equation, since we make use of exactly this correspondence

in our semiclassical analysis. We choose a three mode system in order to

visualize it easily and, moreover, to have a sufficiently interesting

structure, although the method can also be extended to higher dimensional

systems.

\\ ( http://arXiv.org/abs/quant-ph/0604158 , 846kb)

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Paper: quant-ph/0604165

Date: Fri, 21 Apr 2006 16:39:50 GMT (141kb)

Title: Entanglement of orbital angular momentum states between an ensemble of

cold atoms and a photon

Authors: R. Inoue, N. Kanai, T. Yonehara, Y. Miyamoto, M. Koashi and M. Kozuma

Comments: 12 pages, 3 figures

\\

Various atom-photon entangled states can be generated by utilizing

corresponding conservation law. In particular, higher-dimensional entanglement

between an atomic ensemble and a photon is expected to arise from angular

momentum conservation law. Here we demonstrate entanglement of orbital angular

momentum states by utilizing atomic collective excitation and Laguerre-Gaussian

modes of light. Generation of higher-dimensional entanglement between remote

atomic ensembles and an application to condensed matter physics are also

discussed.

\\ ( http://arXiv.org/abs/quant-ph/0604165 , 141kb)

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Paper (*cross-listing*): cond-mat/0604464

Date: Wed, 19 Apr 2006 23:23:40 GMT (117kb)

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: 12 pages, 8 figures

Subj-class: Other; Atomic Physics

\\

We present a 3D quantum mechanical theory of radio-frequency outcoupled atom

lasers from trapped atomic gases in the presence of the gravitational force.

Predictions for the total outcoupling rate as a function of the radio-frequency

and for the beam wave function are given. We establish a sum rule for the

energy integrated outcoupling, which leads to a separate determination of the

coupling strength between the atoms and the radiation field.

For a non-interacting Bose-Einstein condensate analytic solutions are derived

which are subsequently extended to include the effects of atomic interactions.

The interactions enhance interference effects in the beam profile and modify

the outcoupling rate of the atom laser. We provide a complete quantum

mechanical solution which is in line with experimental findings and allows to

determine the validity of commonly used approximative methods.

We also extend the formalism to a fermionic atom laser and analyze the effect

of superfluidity on the outcoupling of atoms.

\\ ( http://arXiv.org/abs/cond-mat/0604464 , 117kb)

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Paper: quant-ph/0601163

replaced with revised version Fri, 21 Apr 2006 10:22:24 GMT (620kb)

Title: Trapping atoms on a transparent permanent-magnet atom chip

Authors: A. Shevchenko, M. Heilio, T. Lindvall, A. Jaakkola, I. Tittonen, M.

Kaivola, T. Pfau

Comments: Modifications: A) Reference I. Barb et al., Eur. Phys. JD, 35, 75

(2005) added. B)Sentence rewritten: We routinely capture more than 10^6 atoms

in a micro-MOT on a magnetized pattern. C) The magnetic field strengths are

now given in Teslas. D) The second sentence in the fourth paragraph has been

rewritten in order to more clearly describe the geometry and purpose of the

compensation coils.E) In the seventh paragraph we have rewritten the sentence

about the creation of the external magnetic field for the magnetic-domain

patterning. F) In the ninth paragraph, we clarify the way to shift the trap

center. G) Caption of Fig. 4 changed. H) We have modified paragraph 12 to

improve the description on the guiding of the trap center along a toroidal

pattern. I) The last two sentences of the manuscript have been rewritten

\\ ( http://arXiv.org/abs/quant-ph/0601163 , 620kb)

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Paper: physics/0604169

Date: Fri, 21 Apr 2006 18:46:55 GMT (99kb)

Title: Resonant electric dipole-dipole interactions between cold Rydberg atoms

in a magnetic field

Authors: K. Afrousheh, P. Bohlouli-Zanjani, J. D. Carter, A. Mugford, J. D. D.

Martin

Comments: Accepted for publication in Physical Review A

Subj-class: Atomic Physics

\\

Laser cooled Rb atoms were optically excited to 46d Rydberg states. A

microwave pulse transferred a fraction of the atoms to the 47p Rydberg state.

The resonant electric dipole-dipole interactions between atoms in these two

states were probed using the linewidth of the two-photon microwave transition

46d-47d. The presence of a weak magnetic field (approximately 0.5 G) reduced

the observed line broadening, indicating that the interaction is suppressed by

the field. The field removes some of the energy degeneracies responsible for

the resonant interaction, and this is the basis for a quantitative model of the

resulting suppression. A technique for the calibration of magnetic field

strengths using the 34s-34p one-photon transition is also presented.

\\ ( http://arXiv.org/abs/physics/0604169 , 99kb)

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Paper: nlin.PS/0604045

Date: Thu, 20 Apr 2006 16:53:49 GMT (257kb)

Date (revised v2): Thu, 20 Apr 2006 20:14:13 GMT (257kb)

Title: Coexistence of Josephson oscillations and novel self-trapping regime in

optical waveguide arrays

Authors: Ramaz Khomeriki, Jerome Leon, Stefano Ruffo

Comments: 4 pages, 4 figures

Subj-class: Pattern Formation and Solitons; Statistical Mechanics; Optics

\\

Considering the coherent nonlinear dynamics between two weakly linked optical

waveguide arrays, we find the first example of coexistence of Josephson

oscillations with a novel self-trapping regime. This macroscopic bistability is

explained by proving analytically the simultaneous existence of symmetric,

antisymmetric and asymmetric stationary solutions of the associated

Gross-Pitaevskii equation. The effect is, moreover, illustrated and confirmed

by numerical simulations. This property allows to conceive an optical switch

based on the variation of the refractive index of the linking central

waveguide.

\\ ( http://arXiv.org/abs/nlin/0604045 , 257kb)

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Paper: cond-mat/0604522

Date: Mon, 24 Apr 2006 12:45:06 GMT (885kb)

Title: A quantitative study of spin noise spectroscopy in a classical gas of

$^{41}$K atoms

Authors: Bogdan Mihaila, Scott A. Crooker, Dwight G. Rickel, Krastan B.

Blagoev, Peter B. Littlewood, and Darryl L. Smith

Report-no: LA-UR-06-2838

Subj-class: Other

\\

We present a general derivation of the electron spin noise power spectrum in

alkali gases as measured by optical Faraday rotation, which applies to both

classical gases at high temperatures as well as ultracold quantum gases. We

show that the spin-noise power spectrum is determined by an electron spin-spin

correlation function, and we find that measurements of the spin-noise power

spectra for a classical gas of $^{41}$K atoms are in good agreement with the

predicted values. Experimental and theoretical spin noise spectra are directly

and quantitatively compared in both longitudinal and transverse magnetic fields

up to the high magnetic field regime (where Zeeman energies exceed the

intrinsic hyperfine energy splitting of the $^{41}$K ground state).

\\ ( http://arXiv.org/abs/cond-mat/0604522 , 885kb)

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Paper: cond-mat/0604525

Date: Sat, 22 Apr 2006 11:10:54 GMT (86kb)

Title: Deconfinement and cold atoms in optical lattices

Authors: M. A. Cazalilla, A. F. Ho and T. Giamarchi

Comments: Proceedings of the conference on "Quantum Many Body Theories 13", to

be published by World Scientific

Subj-class: Strongly Correlated Electrons; Superconductivity

\\

Despite the fact that by now one dimensional and three dimensional systems of

interacting particles are reasonably well understood, very little is known on

how to go from the one dimensional physics to the three dimensional one. This

is in particular true in a quasi-one dimensional geometry where the hopping of

particles between one dimensional chains or tubes can lead to a dimensional

crossover between a Luttinger liquid and more conventional high dimensional

states. Such a situation is relevant to many physical systems. Recently cold

atoms in optical traps have provided a unique and controllable system in which

to investigate this physics. We thus analyze a system made of coupled one

dimensional tubes of interacting fermions. We explore the observable

consequences, such as the phase diagram for isolated tubes, and the possibility

to realize unusual superfluid phases in coupled tubes systems.

\\ ( http://arXiv.org/abs/cond-mat/0604525 , 86kb)

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Paper: cond-mat/0604530

Date: Sun, 23 Apr 2006 10:06:37 GMT (99kb)

Title: Asymmetric Fermi superfluid in a harmonic trap

Authors: C.-H. Pao and S.-K. Yip

Comments: 15 pages, 5 figures

Subj-class: Other; Superconductivity

\\

We consider a dilute two-component atomic fermion gas with unequal

populations in a harmonic trap potential using the mean field theory and the

local density approximation. We show that the system is phase separated into

concentric shells with the superfluid in the core surrounded by the normal

fermion gas in both the weak-coupling BCS side and near the Feshbach resonance.

In the strong-coupling BEC side, the composite bosons and left-over fermions

can be mixed. We calculate the cloud radii and compare axial density profiles

systemically for the BCS, near resonance and BEC regimes.

\\ ( http://arXiv.org/abs/cond-mat/0604530 , 99kb)

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Paper: cond-mat/0604550

Date: Mon, 24 Apr 2006 15:10:55 GMT (33kb)

Title: Condensation temperature of interacting Bose gases with and without

disorder

Authors: O. Zobay

Comments: 7 pages, 2 figures

Subj-class: Statistical Mechanics

Journal-ref: Phys. Rev. A 73, 023616 (2006)

DOI: 10.1103/PhysRevA.73.023616

\\

The momentum-shell renormalization group (RG) is used to study the

condensation of interacting Bose gases without and with disorder. First of all,

for the homogeneous disorder-free Bose gas the interaction-induced shifts in

the critical temperature and chemical potential are determined up to second

order in the scattering length. The approach does not make use of dimensional

reduction and is thus independent of previous derivations. Secondly, the RG is

used together with the replica method to study the interacting Bose gas with

delta-correlated disorder. The flow equations are derived and found to reduce,

in the high-temperature limit, to the RG equations of the classical

Landau-Ginzburg model with random-exchange defects. The random fixed point is

used to calculate the condensation temperature under the combined influence of

particle interactions and disorder.

\\ ( http://arXiv.org/abs/cond-mat/0604550 , 33kb)

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Paper: cond-mat/0404577

replaced with revised version Mon, 24 Apr 2006 08:42:33 GMT (45kb)

Title: Deformed Fermi surfaces in ultracold Fermi gases

Authors: Armen Sedrakian, Jordi Mur-Petit, Artur Polls, Herbert M\"uther

Comments: v1: 12 pages, including 3 figures; v2: 5 pages, 3 figures, minor

corrections. See cond-mat/0504511 for the expanded work

Subj-class: Superconductivity

\\ ( http://arXiv.org/abs/cond-mat/0404577 , 45kb)

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Paper: cond-mat/0604557

Date: Mon, 24 Apr 2006 20:02:41 GMT (140kb)

Title: Stable skyrmions in spinor condensates

Authors: Igor F. Herbut and Masaki Oshikawa

Comments: 4 pages, 2 figures

Subj-class: Superconductivity; Statistical Mechanics

\\

Globally symmetric spinor condensates in free space are argued not to support

stable topological defects in either two or three dimensions. In the latter

case, however, we show that a topological skyrmion can be stabilized by forcing

it to adopt certain density profiles. A sufficient condition for the existence

of a stable skyrmion in three dimensions is formulated and illustrated in

simple examples. Our results pertain to Bose-Einstein condensation in Rb.

\\ ( http://arXiv.org/abs/cond-mat/0604557 , 140kb)

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Paper: cond-mat/0604558

Date: Tue, 25 Apr 2006 15:08:53 GMT (940kb)

Title: Phase diagram of a polarized Fermi gas across a Feshbach resonance in a

potential trap

Authors: W. Yi and L.-M. Duan

Comments: 9 pages, 4 figures

Subj-class: Other

\\

We map out the detailed phase diagram of a trapped ultracold Fermi gas with

population imbalance across a wide Feshbach resonance. We show that under the

local density approximation, the properties of the atoms in any (anisotropic)

harmonic traps are universally characterized by three dimensionless parameters:

the normalized temperature, the dimensionless interaction strength, and the

population imbalance. We then discuss the possible quantum phases in the trap,

and quantitatively characterize their phase boundaries in various typical

parameter regions.

\\ ( http://arXiv.org/abs/cond-mat/0604558 , 940kb)

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Paper: cond-mat/0604565

Date: Tue, 25 Apr 2006 08:07:14 GMT (9kb)

Title: Quantum Depletion of a Soliton Condensate

Authors: Guoxiang Huang, L. Deng, Jiaren Yan, and Bambi Hu

Comments: 11 pages

Subj-class: Other

\\

We present rigorous results on the diagonalization of Bogoliubov Hamilto-

nian for a soliton condensate. Using the complete and orthonomalized set of

eigenfunction for the Bogoliubov de Gennes equations, we calculate ex- actly

the quantum depletion of the condensate and show that two degenerate

zero-modes, which originate from a U(1) guage- and a translational-symmetry

breaking of the system, induce the quantum diffusion and transverse instabil-

ity of the soliton condensate.

\\ ( http://arXiv.org/abs/cond-mat/0604565 , 9kb)

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Paper: cond-mat/0604572

Date: Tue, 25 Apr 2006 12:07:45 GMT (78kb)

Title: Resonant pairing between Fermions with unequal masses

Authors: S.-T. Wu, C.-H. Pao and S.-K. Yip

Comments: 10 pages, 4 figures

Subj-class: Superconductivity; Other

\\

We study the pairing between Fermions of different masses, especially at the

unitary limit. At equal populations, the thermodynamic properties are identical

with the equal mass case provided an appropriate rescaling is made. At unequal

populations, for sufficiently light majority species, the system does not phase

separate. For sufficiently heavy majority species, the phase separated normal

phase have a density larger than that of the superfluid. For atoms in harmonic

traps, the density profiles for unequal mass Fermions can be drastically

different from their equal-mass counterparts.

\\ ( http://arXiv.org/abs/cond-mat/0604572 , 78kb)

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Paper (*cross-listing*): nucl-th/0604053

Date: Fri, 21 Apr 2006 04:39:31 GMT (497kb)

Title: Universality in a 2-component Fermi System at Finite Temperature

Authors: Gautam Rupak

Comments: 10 pages, 6 figures, LaTeX2e

Report-no: INT PUB-06 5

Subj-class: Nuclear Theory; Statistical Mechanics

\\

Thermodynamic properties of a fermionic system close to the unitarity limit,

where the 2-body scattering length |a| approaches infinity is studied at high

temperature Boltzmann regime. For dilute systems the virial expansion

coefficients in the Boltzmann regime are expected, from general arguments, to

be universal. A model independent finite temperature T calculation of the third

virial coefficient b3(T) is presented. At the unitarity limit, b3(T) = -0.48 is

an universal number. The energy density up to the third virial expansion is

derived. These results are relevant for dilute neutron matter and could be

tested in current atomic experiments on dilute fermionic gases near the

Feshbach resonance.

\\ ( http://arXiv.org/abs/nucl-th/0604053 , 497kb)

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Paper: cond-mat/0507399

replaced with revised version Tue, 25 Apr 2006 14:15:08 GMT (20kb)

Title: The unitary three-body problem in a trap

Authors: F\'{e}lix Werner (LKB - Lhomond), Yvan Castin (LKB - Lhomond)

Comments: 4 pages

Proxy: ccsd ccsd-00007574

Subj-class: Other

\\ ( http://arXiv.org/abs/cond-mat/0507399 , 20kb)

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Paper: cond-mat/0508010

replaced with revised version Tue, 25 Apr 2006 07:40:29 GMT (34kb)

Title: Production efficiency of Feshbach molecules in fermion systems

Authors: B. E. Dobrescu, V. L. Pokrovsky

Comments: 4 pages, 1 figure

Subj-class: Statistical Mechanics

Journal-ref: Phys. Lett. A 350, 154 (2006)

DOI: 10.1016/j.physleta.2005.10.009

\\ ( http://arXiv.org/abs/cond-mat/0508010 , 34kb)

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Paper: cond-mat/0604416

replaced with revised version Tue, 25 Apr 2006 06:57:14 GMT (337kb)

Title: Crossover States of Vortex Matter in Trapped Bose Condensates

Authors: S. Kragset, E. Babaev and A. Sudbo

Comments: v2: figure quality improved

Subj-class: Statistical Mechanics

\\ ( http://arXiv.org/abs/cond-mat/0604416 , 337kb)

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Paper: cond-mat/0604580

Date: Tue, 25 Apr 2006 20:33:15 GMT (16kb)

Title: Superfluidity in a Three-flavor Fermi Gas with SU(3) Gauge Symmetry

Authors: Lianyi He, Meng Jin and Pengfei Zhuang (Tsinghua U.)

Comments: 10 pages, 2 figures

Subj-class: Other

\\

We investigate the superfluidity and the associated Nambu-Goldstone modes in

a three-flavor atomic Fermi gas with SU(3) gauge symmetry. The s-wave pairing

occurs in flavor anti-triplet channel due to the Pauli principle. The

superfluid state contains both gapped and gapless fermionic excitations, and

the SU(3) gauge symmetry group is spontaneously broken to a SU(2) subgroup.

Since five generators of SU(3) group are broken, we expect five Nambu-Goldstone

modes will appear. However, we only find three Nambu-Goldstone modes. One

Nambu-Goldstone mode has linear dispersion law and the other two

Nambu-Goldstone mode have quadratic dispersion law. The additional two

collective modes obtain a mass gap. This mass gap is of order the energy gap of

fermions in a wide range of the coupling. The abnormal number of

Nambu-Goldstone modes, the quadratic dispersion law and the mass gap have

significant effect on the low temperature thermodynamics of the matter.

\\ ( http://arXiv.org/abs/cond-mat/0604580 , 16kb)

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Paper: cond-mat/0604600

Date: Wed, 26 Apr 2006 17:47:36 GMT (367kb)

Title: High field fractional quantum Hall effect in optical lattices

Authors: R. N. Palmer, D. Jaksch

Comments: 4 pages, 4 figures, accepted by PRL

Subj-class: Mesoscopic Systems and Quantum Hall Effect

\\

We consider interacting bosonic atoms in an optical lattice subject to a

large simulated magnetic field. We develop a model similar to a bilayer

fractional quantum Hall system valid near simple rational numbers of magnetic

flux quanta per lattice cell. Then we calculate its ground state, magnetic

lengths, fractional fillings, and find unexpected sign changes in the Hall

current. Finally we study methods for detecting these novel features via shot

noise and Hall current measurements.

\\ ( http://arXiv.org/abs/cond-mat/0604600 , 367kb)

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Paper: physics/0604061

replaced with revised version Tue, 25 Apr 2006 14:23:42 GMT (751kb)

Title: 6-axis inertial sensor using cold-atom interferometry

Authors: B. Canuel, F. Leduc, D. Holleville, A. Gauguet, J. Fils, A. Virdis, A.

Clairon, N. Dimarcq, Ch. J. Borde, P. Bouyer, A. Landragin

Comments: submitted to PRL

Subj-class: Atomic Physics

\\ ( http://arXiv.org/abs/physics/0604061 , 751kb)

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Paper: cond-mat/0604625

Date: Thu, 27 Apr 2006 15:55:06 GMT (422kb)

Title: Signatures of the superfluid to Mott-insulator transition in the

excitation spectrum of ultracold atoms

Authors: S.R. Clark and D. Jaksch

Comments: 17 pages and 11 figures

Subj-class: Other

\\

We present a detailed analysis of the dynamical response of ultra-cold

bosonic atoms in a one-dimensional optical lattice subjected to a periodic

modulation of the lattice depth. Following the experimental realization by

Stoferle et al [Phys. Rev. Lett. 92, 130403 (2004)] we study the excitation

spectrum of the system as revealed by the response of the total energy as a

function of the modulation frequency Omega. By using the Time Evolving Block

Decimation algorithm, we are able to simulate one-dimensional systems

comparable in size to those in the experiment, with harmonic trapping and

across many lattice depths ranging from the Mott-insulator to the superfluid

regime. Our results produce many of the features seen in the experiment, namely

a broad response in the superfluid regime, and narrow discrete resonances in

the Mott-insulator regime. We identify several signatures of the

superfluid-Mott insulator transition that are manifested in the spectrum as it

evolves from one limit to the other.

\\ ( http://arXiv.org/abs/cond-mat/0604625 , 422kb)

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Paper: cond-mat/0509693

replaced with revised version Thu, 27 Apr 2006 19:39:12 GMT (29kb)

Title: Superfluidity without Symmetry-Breaking: The Time-Dependent Hartree-Fock

Approximation for Bose-Condensed Systems

Authors: C.-H. Zhang and H.A. Fertig

Comments: 2 figure. Submitted to PRA

Subj-class: Mesoscopic Systems and Quantum Hall Effect

\\ ( http://arXiv.org/abs/cond-mat/0509693 , 29kb)

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Paper: quant-ph/0604205

Date: Thu, 27 Apr 2006 15:25:58 GMT (721kb)

Title: Analytical solutions for the dynamics of two trapped interacting

ultracold atoms

Authors: Zbigniew Idziaszek, Tommaso Calarco

Comments: RevTeX, 15 pages, 15 figures

\\

We discuss exact solutions of the Schroedinger equation for the system of two

ultracold atoms confined in an axially symmetric harmonic potential. We

investigate different geometries of the trapping potential, in particular we

study the properties of eigenenergies and eigenfunctions for quasi-one- and

quasi-two-dimensional traps. We show that the quasi-one- and the

quasi-two-dimensional regimes for two atoms can be already realized in the

traps with moderately large (or small) ratios of the trapping frequencies in

the axial and the transverse directions. Finally, we apply our theory to

Feshbach resonances for trapped atoms. Introducing in our description an

energy-dependent scattering length we calculate analytically the eigenenergies

for two trapped atoms in the presence of a Feshbach resonance.

\\ ( http://arXiv.org/abs/quant-ph/0604205 , 721kb)

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Paper: physics/0604220

Date: Thu, 27 Apr 2006 17:31:48 GMT (313kb)

Title: Analysis of the atom-number correlation function in a few-atom trap

Authors: Youngwoon Choi, Seokchan Yoon, Sungsam Kang, Woongnae Kim, Jai-Hyung

Lee, and Kyungwon An

Comments: 5 pages, 3 figures

Subj-class: Atomic Physics

\\

Stochastic properties of loading and loss mechanism in a few atom trap are

analyzed. An approximate formula is derived for the atom-number correlation

function for the trapped atoms in the limit of reasonably small two-atom loss

rate. Validity of the approximate formula is confirmed by numerical

simulations.

\\ ( http://arXiv.org/abs/physics/0604220 , 313kb)

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Paper: cond-mat/0604638

Date: Fri, 28 Apr 2006 03:22:33 GMT (363kb)

Title: Surface tension in population imbalanced unitary Fermi gases

Authors: Theja N. De Silva, Erich J. Mueller

Comments: 4 pages, 4 figures

Subj-class: Other

\\

We study the effects of surface tension between normal and superfluid regions

of a trapped Fermi gas at unitarity. We find that surface tension causes

notable distortions in the shape of large aspect ratio clouds. Including these

distortions in our theories resolves many of the apparent discrepancies among

different experiments and between theory and experiments.

\\ ( http://arXiv.org/abs/cond-mat/0604638 , 363kb)

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Paper: cond-mat/0604671

Date: Fri, 28 Apr 2006 16:30:48 GMT (677kb)

Title: Theory of Ultracold Superstrings

Authors: Michiel Snoek, S. Vandoren, and H.T.C. Stoof

Comments: 16 pages, 9 figures

Subj-class: Other

\\

The combination of a vortex line in a one-dimensional optical lattice with

fermions bound to the vortex core makes up an ultracold superstring. We give a

detailed derivation of the way to make this supersymmetric string in the

laboratory. In particular, we discuss the presence of a fermionic bound state

in the vortex core and the tuning of the laser beams needed to achieve

supersymmetry. Moreover, we discuss experimental consequences of supersymmetry

and identify the precise supersymmetry in the problem. Finally, we make the

mathematical connection with string theory.

\\ ( http://arXiv.org/abs/cond-mat/0604671 , 677kb)

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Paper: cond-mat/0604673

Date: Fri, 28 Apr 2006 17:08:53 GMT (127kb)

Title: Evolution from a Bose-Einstein Condensate to a Tonks-Girardeau Gas: An

Exact Diagonalization Study

Authors: Frank Deuretzbacher, Kai Bongs, Klaus Sengstock, Daniela Pfannkuche

Comments: 5 pages, 5 figures

Subj-class: Other

\\

We study ground state properties of spinless, quasi one-dimensional bosons

which are confined in a harmonic trap and interact via repulsive

delta-potentials. We use the exact diagonalization method to analyze the

pair-correlation function, as well as the density, the momentum distribution,

different contributions to the energy and the population of single particle

orbitals in the whole interaction regime. In particular, we are able to trace

the fascinating transition from bosonic to fermi-like behavior in

characteristic features of the momentum distribution which is accessible to

experiments. Our calculations yield quantitative measures for the interaction

strength limiting the mean-field regime on one side and the Tonks-Girardeau

regime on the other side of an intermediate regime.

\\ ( http://arXiv.org/abs/cond-mat/0604673 , 127kb)

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Paper: quant-ph/0604214

Date: Fri, 28 Apr 2006 17:23:15 GMT (561kb)

Title: Wave-Particle Fluctuations, Coherence, and Bose-Einstein Condensation

Authors: N. M. Chase

\\

By extending Einstein's separation of wave and particle parts of the second

order thermal fluctuation to encompass "generalized fluctuations" in any Bose

field, P. E. Gordon has proposed alternative definitions for nth order

coherence and nth order coherent states. The main point of this paper is to

explore some of the physical insights to be gained by extending dualism to

higher orders. Recent experiments have examined aspects of the coherence of

Bose-Einstein condensates. It has been argued that the condensate state is

coherent to (at least) second or third order, but the coherence properties of

Bose-Einstein condensates remain somewhat controversial. Using probability

distributions developed by M. O. Scully and V. V. Kocharovsky et. al., we apply

Gordon's dualistic expression of the coherence conditions to investigate

coherence properties in Bose-Einstein condensation. Via numerical calculations,

we present a graphical survey of wave-like and particle-like fluctuations in

condensed and uncondensed fractions. Near the critical point, we find a very

marked peak in the ratio of nth order wave to nth order particle fluctuations

in the condensate. Not surprisingly, n-point correlations between the positions

of condensate atoms also peak near the critical temperature, and this

apparently mirrors, to higher orders, the well-known relation between the

integral of the 2-point correlation function over a certain volume and the rms

fluctuation in the number of particles in that volume.

\\ ( http://arXiv.org/abs/quant-ph/0604214 , 561kb)

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Paper: cond-mat/0605005

Date: Mon, 1 May 2006 01:49:18 GMT (50kb)

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

Subj-class: Superconductivity

\\

In this chapter the recent theoretical work on phase transition in imbalanced

fermion superfluids is reviewed. The imbalanced systems are those in which the

two fermionic species candidate to form pairing have different Fermi surfaces

or densities. We consider systems subjected to weak interactions. In this

scenario two distinct phase transitions are predicted to occur. A

thermodynamical phase transition, induced by the temperature (T), and a quantum

phase transition as a function of the increasing chemical potentials asymmetry,

that takes place at zero temperature. We also briefly discuss some recent

experimental work at non-zero T with imbalanced Fermi gases in cold atomic

traps.

\\ ( http://arXiv.org/abs/cond-mat/0605005 , 50kb)

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Paper: cond-mat/0605038

Date: Mon, 1 May 2006 18:06:15 GMT (211kb)

Title: The evolution of additional (hidden) quantum variables in the

interference of Bose-Einstein condensates

Authors: W. J. Mullin, R. Krotkov, and F. Lalo\"{e}

Comments: 27 pages, 7 figures

Subj-class: Other

\\

Additional variables (also often called ``hidden variables'') are sometimes

added to standard quantum mechanics in order to remove its indeterminism or

``incompletness,'' and to make the measurement process look more classical.

Here we discuss a case in which an additional variable arises almost

spontaneously from the quantum formalism: the emergence of relative phase

between two highly populated Fock state Bose-Einstein condensates. The model

simulated here involves the interference of two Bose condensates, one with all

up spins, and the other with down spins, along a z-axis. With the clouds

overlapping, we consider the results of measuring spins in a transverse plane

(the general direction is studied in an appendix). The determination of the

previously ``hidden'' phase becomes progressively more definite as additional

measurements are made. We also provide an analysis of a recent and closely

related experiment.

\\ ( http://arXiv.org/abs/cond-mat/0605038 , 211kb)

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Paper: cond-mat/0605039

Date: Mon, 1 May 2006 19:07:46 GMT (61kb)

Title: Intermediate temperature superfluidity in an atomic Fermi gas with

population imbalance

Authors: Chih-Chun Chien, Qijin Chen, Yan He, and K. Levin

Comments: 4 pages, 4 EPS figures, submitted to PRL

Subj-class: Strongly Correlated Electrons; Superconductivity

\\

We derive the underlying finite temperature theory which describes Fermi gas

superfluidity in the presence of population imbalance. We address the behavior

of the pair formation and superfluid transition temperatures, and of the

superfluid density and thereby present a complete phase diagram for a

homogeneous system. In the fermionic regime, we show how thermal effects can

enhance pairing and stabilize the polarized superfluid phase away from T=0.

Importantly, at unitarity the polarized state is an ``intermediate temperature

superfluid".

\\ ( http://arXiv.org/abs/cond-mat/0605039 , 61kb)

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Paper: cond-mat/0512134

replaced with revised version Fri, 28 Apr 2006 21:52:39 GMT (84kb)

Title: Acoustic attenuation probe for fermion superfluidity in ultracold atom

gases

Authors: Sergio Gaudio (1)(2), B. Mihaila (2), K. B. Blagoev (2), K. S. Bedell

(1), Eddy Timmermans (2) (1) (Department of Physics, Boston College) (2)

(Theoretical Division, Los Alamos Natl Labs)

Comments: 4 pages, 2 figures. Revised version

Report-no: LAUR-05-3432

Subj-class: Other

\\ ( http://arXiv.org/abs/cond-mat/0512134 , 84kb)

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\\

Paper: quant-ph/0502011

replaced with revised version Fri, 28 Apr 2006 20:33:44 GMT (115kb)

Title: Deterministic Entanglement via Molecular Dissociation in Integrated Atom

Optics

Authors: Bo Zhao, Zeng-Bing Chen, Jian-Wei Pan, J. Schmiedmayer, Alessio

Recati, Grigory E. Astrakharchik, Tommaso Calarco

Comments: 4 pages, 3 figures

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

\\ ( http://arXiv.org/abs/quant-ph/0502011 , 115kb)

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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 Wed May 03 2006 - 08:47:24 EST

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