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

Date: Mon, 14 Jun 2010 22:24:58 +1000

Date: Mon, 14 Jun 2010 22:24:58 +1000

Dear subscribers,

This week's selection was compiled by Chao Feng, and contains 38 new abstracts

and 12 replacements.

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arXiv:1003.3048 (*cross-listing*)

Date: Mon, 15 Mar 2010 23:21:56 GMT (173kb)

Date (revised v2): Tue, 18 May 2010 20:08:15 GMT (339kb,D)

Title: Tunable disorder in a crystal of cold polar molecules

Authors: Felipe Herrera and Marina Litinskaya and Roman V. Krems

Categories: physics.atom-ph cond-mat.other physics.chem-ph quant-ph

\\

In the present work, we demonstrate the possibility of controlling by an

external field the dynamics of collective excitations (excitons) of molecules

on an optical lattice. We show that a suitably chosen two-species mixture of

ultracold polar molecules loaded on an optical lattice forms a phononless

crystal, where exciton-impurity interactions can be controlled by applying an

external electric field. This can be used for the controlled creation of

many-body entangled states of ultracold molecules and the time-domain quantum

simulation of disorder-induced localization and delocalization of quantum

particles.

\\ ( http://arxiv.org/abs/1003.3048 , 339kb)

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arXiv:1005.2420

Date: Thu, 13 May 2010 20:33:46 GMT (398kb)

Title: Comment on "Inequivalence between the Schrodinger equation and the

Madelung hydrodynamic equations"

Authors: Vel Hushwater

Categories: quant-ph

\\

In the paper with the above-noted title, T. C. Wallstrom claims that the

description of the particle's motion as a certain "conservative" diffusion is

not equivalent to quantum mechanics in spite of the fact that the Madelung

"hydrodynamic" equations, which provide the description of such a diffusion,

can be converted to the Schrodinger equation. He pointed out that such a

stochastic theory can be regarded as equivalent to conventional quantum

mechanics only if they can derive from it not just the Madelung equations but

also the condition that the circulation of the "probability fluid" is always

quantized, which is equivalent the condition for the single-valuedness of the

wave function. We, however, show that the single-valuedness of the wave

function required in quantum mechanics, is not an auxiliary condition but a

property of all solutions of the Schrodinger equation. Based on the one-to-one

correspondence between solutions of the Schrodinger and the Madelung equations

this means that the quantization of the circulation of the "probability fluid"

is a property of all solutions of the Madelung equations.

\\ ( http://arxiv.org/abs/1005.2420 , 398kb)

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arXiv:1005.2483

Date: Fri, 14 May 2010 09:25:20 GMT (400kb)

Title: Disordered one-dimensional Bose-Fermi mixtures: The Bose-Fermi glass

Authors: Fran\c{c}ois Cr\'epin, Gergely Zar\'and, Pascal Simon

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

Comments: 4 pages, 2 figures

\\

We analyze an interacting Bose-Fermi mixture in a 1D disordered potential

using a combination of renormalization group and variational methods. We obtain

the complete phase diagram in the incommensurate case as a function of bosonic

and inter-species interaction strengths, in the weak disorder limit. We find

that the system is characterized by several phase transitions between

superfluid and various glassy insulating states, including a new Bose-Fermi

glass phase, where both species are coupled and localized. We show that the

dynamical structure factor, as measured through Bragg scattering experiments,

can distinguish between the various localized phases and probe their dynamics.

\\ ( http://arxiv.org/abs/1005.2483 , 400kb)

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arXiv:1005.2493

Date: Fri, 14 May 2010 10:23:18 GMT (173kb)

Title: Collective excitations of a dipolar Bose-Einstein condensate

Authors: G. Bismut, B. Pasquiou, E. Mar\'echal, P. Pedri, L. Vernac, O. Gorceix

and B. Laburthe-Tolra

Categories: cond-mat.quant-gas quant-ph

Comments: 4 pages, 4 figures

\\

We have measured the effect of dipole-dipole interactions on the frequency of

a collective mode of a Bose-Einstein condensate. At relatively large numbers of

atoms, the experimental measurements are in good agreement with zero

temperature theoretical predictions based on the Thomas Fermi approach.

Experimental results obtained for the dipolar shift of a collective mode show a

larger dependency to both the trap geometry and the atom number than the ones

obtained when measuring the modification of the condensate aspect ratio due to

dipolar forces. These findings are in good agreement with simulations based on

a gaussian ansatz.

\\ ( http://arxiv.org/abs/1005.2493 , 173kb)

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arXiv:1005.2520

Date: Fri, 14 May 2010 13:26:56 GMT (41kb,D)

Title: Asymptotically exact trial wave functions for yrast states of rotating

Bose gases

Authors: Susanne Viefers and Mathieu Taillefumier

Categories: cond-mat.quant-gas

\\

We revisit the composite fermion (CF) construction of the lowest angular

momentum yrast states of rotating Bose gases with weak short range interaction.

For angular momenta at and below the single vortex, $L \leq N$, the overlaps

between these trial wave functions and the corresponding exact solutions {\it

increase} with increasing system size and appear to approach unity in the

thermodynamic limit. In the special case $L=N$, this remarkable behaviour was

previously observed numerically. Here we present methods to address this point

analytically, and find strongly suggestive evidence in favour of similar

behaviour for all $L \leq N$. While not constituting a fully conclusive proof

of the converging overlaps, our results do demonstrate a striking similarity

between the analytic structure of the exact ground state wave functions at $L

\leq N$, and that of their CF counterparts. Results are given for two different

projection methods commonly used in the CF approach.

\\ ( http://arxiv.org/abs/1005.2520 , 41kb)

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arXiv:1005.2559

Date: Fri, 14 May 2010 15:55:51 GMT (437kb,D)

Title: Multipartite entangled states with two bosonic modes and qubits

Authors: P. P. Munhoz, F. L. Semi\~ao

Categories: quant-ph

Comments: 10 pages, 5 figures, REVTeX 4.1, BibTeX

\\

We theoretically investigate the role of different phases of coupling

constants in the dynamics of atoms and two cavity modes, observing

deterministic generation of prototype or hybrid Bell, W, GHZ, and cluster

states. Commonly induced dipole-dipole interactions (far-off resonance) are

inhibited between particular pairs of qubits under suitable choice of that

phases. We evaluate the generation fidelities when imperfections such as

dissipative environments and time precision errors are considered. We show

violation of local realism for the generated cluster state under such

imperfections, even when approaching the weak coupling regime.

\\ ( http://arxiv.org/abs/1005.2559 , 437kb)

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arXiv:1005.2576

Date: Fri, 14 May 2010 17:19:53 GMT (144kb)

Title: Double resonances in Borromean heteronuclear triatomic systems

Authors: F. Bringas, M. T. Yamashita, T. Frederico and L. Tomio

Categories: cond-mat.quant-gas physics.atom-ph

\\

We investigate the occurrence of Borromean three-body continuum s-wave

resonances, in an $\alpha\alpha\beta$ system for large negative two-body

scattering lengths. The energy and width are determined by a scaling function

with arguments given by energy ratios of the two-body virtual state subsystem

energies with the shallowest three-body bound state. The Borromean continuum

resonances emerging from Efimov states present a peculiar behavior for trapped

ultracold atoms near a Feshbach resonance: two resonances with equal energies

at different values of the scattering length. The corresponding three-body

recombination peaks should merge as the temperature is raised, with one moving

towards lower values of the scattering length as the other moves to larger

values.

\\ ( http://arxiv.org/abs/1005.2576 , 144kb)

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arXiv:1005.2581 (*cross-listing*)

Date: Fri, 14 May 2010 17:41:53 GMT (59kb)

Title: A Performance Comparison of CUDA and OpenCL

Authors: Kamran Karimi, Neil G. Dickson, and Firas Hamze

Categories: cs.PF cs.DC physics.comp-ph

Comments: 10 pages, 6 Tables, 5 Figures

\\

CUDA and OpenCL offer two different interfaces for programming GPUs. OpenCL

is an open standard that can be used to program CPUs, GPUs, and other devices

from different vendors, while CUDA is specific to NVIDIA GPUs. Although OpenCL

promises a portable language for GPU programming, its generality may entail a

performance penalty. In this paper, we compare the performance of CUDA and

OpenCL using complex, near-identical kernels. We show that when using NVIDIA

compiler tools, converting a CUDA kernel to an OpenCL kernel involves minimal

modifications. Making such a kernel compile with ATI's build tools involves

more modifications. Our performance tests measure and compare data transfer

times to and from the GPU, kernel execution times, and end-to-end application

execution times for both CUDA and OpenCL.

\\ ( http://arxiv.org/abs/1005.2581 , 59kb)

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arXiv:1005.2610

Date: Fri, 14 May 2010 19:16:19 GMT (2549kb)

Title: Generation of inter-component dispersive shocks and dark-bright soliton

trains in counterflowing superfluids

Authors: C. Hamner, J.J. Chang, P. Engels, M. A. Hoefer

Categories: cond-mat.quant-gas

Comments: 5 pages, 4 figures

\\

Superfluids can exhibit an intriguing variety of nonlinear effects. Using two

distinguishable components of a Bose-Einstein condensate, we investigate the

counterflow of two superfluids in a narrow channel. We present the first

experimental observation of inter-component dispersive shock waves and

demonstrate that they consist of trains of dark-bright solitons. Our

observations are theoretically interpreted with three-dimensional numerical

simulations of coupled Gross-Pitaevskii equations. Nonlinear self-steepening as

well as a counterflow-induced modulational instability are identified as two

central processes in the dynamics. We also present the first experimental

evidence for a novel dark-dark soliton in a binary BEC that we observe during

the mixing of two superfluid components.

\\ ( http://arxiv.org/abs/1005.2610 , 2549kb)

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arXiv:1005.2635

Date: Fri, 14 May 2010 21:55:37 GMT (88kb)

Title: Coherence freeze in an optical lattice investigated via pump-probe

spectroscopy

Authors: Samansa Maneshi, Chao Zhuang, Christopher R. Paul, Luciano S. Cruz,

and Aephraim M. Steinberg

Categories: quant-ph

Comments: 4 pages, 5 figures

\\

Motivated by our observation of fast echo decay and a surprising coherence

freeze, we have developed a pump-probe spectroscopy technique for vibrational

states of ultracold $^{85}$Rb atoms in an optical lattice to gain information

about the memory dynamics of the system. We use pump-probe spectroscopy to

monitor the time-dependent changes of frequencies experienced by atoms and to

characterize the probability distribution of these frequency trajectories. We

show that the inferred distribution, unlike a naive microscopic model of the

lattice, correctly predicts the main features of the observed echo decay.

\\ ( http://arxiv.org/abs/1005.2635 , 88kb)

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arXiv:1005.2645

Date: Sat, 15 May 2010 01:48:28 GMT (87kb)

Title: Time-resolved density correlations as probe of squeezing in toroidal

Bose-Einstein condensates

Authors: Michael Uhlmann

Categories: cond-mat.quant-gas

Comments: 18 pages, IOP style

\\

I study the evolution of mean field and linear quantum fluctuations in a

toroidal Bose-Einstein condensate, whose interaction strength is quenched from

a finite (repulsive) value to zero. The azimuthal equal-time density-density

correlation function is calculated and shows temporal oscillations with twice

the (final) excitation frequencies after the transition. These oscillations are

a direct consequence of positive and negative frequency mixing during

non-adiabatic evolution. I will argue that a time-resolved measurement of the

equal-time density correlator might be used to calculate the moduli of the

Bogoliubov coefficients and thus the amount of squeezing imposed on a mode,

i.e., the number of atoms excited out of the condensate.

\\ ( http://arxiv.org/abs/1005.2645 , 87kb)

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arXiv:1005.2649

Date: Sat, 15 May 2010 04:49:14 GMT (303kb)

Title: System size scaling of topological defect creation in a second-order

dynamical quantum phase transition

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

Categories: cond-mat.stat-mech gr-qc quant-ph

Comments: 19 pages of IOP style, 6 figures

\\

We investigate the system size scaling of the net defect number created by a

rapid quench in a second-order quantum phase transition from an O(N) symmetric

state to a phase of broken symmetry. Using a controlled mean-field expansion

for large $N$, we find that the net defect number variance in general convex

volumina scales like the surface area of the sample. For short-range

correlations, this behaviour follows generally from spatial and internal

symmetries. Conversely, if spatial isotropy is broken, e.g., by a lattice, and

in addition long-range periodic correlations develop in the broken-symmetry

phase, we get the rather counterintuitive result that the scaling strongly

depends on the dimension being even or odd: For even dimensions, the net defect

number variance scales like the surface area squared, with a prefactor

oscillating with the system size, while for odd dimensions, it essentially

vanishes.

\\ ( http://arxiv.org/abs/1005.2649 , 303kb)

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arXiv:1005.2751

Date: Sun, 16 May 2010 14:13:27 GMT (4kb)

Title: Finite temperature Schr\"odinger Equation

Authors: Xiang-Yao Wu, Xiao-Jing Liu, Bai-Jun Zhang, Yi-Heng Wu, Qing-Cai Wang,

Yan Wang and Jing-Wu Li

Categories: physics.gen-ph quant-ph

\\

We know the Schr\"odinger equation describes the dynamics of quantum systems,

which didn't include temperature. In this paper, we propose a new finite

temperature Schr\"odinger equation, which can describe the quantum systems in

an arbitrary temperature.

\\ ( http://arxiv.org/abs/1005.2751 , 4kb)

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arXiv:1005.2864

Date: Mon, 17 May 2010 10:15:29 GMT (52kb)

Title: Turbulent superfluid as continuous vortex mixture

Authors: V.I. Yukalov

Categories: cond-mat.quant-gas quant-ph

Comments: Latex file, 22 pages, one figure

Journal-ref: Laser Phys. Lett. 7 (2010) 467-476

\\

A statistical model is advanced for describing quantum turbulence in a

superfluid system with Bose-Einstein condensate. Such a turbulent superfluid

can be realized for trapped Bose atoms subject to either an alternating

trapping potential or to an alternating magnetic field modulating the atomic

scattering length by means of Feshbach resonance. The turbulent system is

represented as a continuous mixture of states each of which is characterized by

its own vorticity corresponding to a particular vortex.

\\ ( http://arxiv.org/abs/1005.2864 , 52kb)

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arXiv:1005.2938

Date: Mon, 17 May 2010 14:47:08 GMT (1375kb)

Title: Correlation versus commensurability effects for finite bosonic systems

in one-dimensional lattices

Authors: Ioannis Brouzos and Sascha Z\"ollner and Peter Schmelcher

Categories: cond-mat.quant-gas quant-ph

Comments: 16 pages, 16 figures

Journal-ref: Phys. Rev. A 81, 053613 (2010)

DOI: 10.1103/PhysRevA.81.053613

\\

We investigate few-boson systems in finite one-dimensional multi-well traps

covering the full interaction crossover from uncorrelated to fermionized

particles. Our treatment of the ground state properties is based on the

numerically exact Multi-Configurational Time-Dependent Hartree method. For

commensurate filling we trace the fingerprints of localisation, as the

interaction strength increases, in several observables like reduced density

matrices, fluctuations and momentum distribution. For filling factor larger

than one we observe on-site repulsion effects in the densities and

fragmentation of particles beyond the validity of the Bose-Hubbard model upon

approaching the Tonks-Girardeau limit. The presence of an incommensurate

fraction of particles induces incomplete localisation and spatial modulations

of the density profiles, taking into account the finite size of the system.

\\ ( http://arxiv.org/abs/1005.2938 , 1375kb)

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arXiv:1005.3040

Date: Mon, 17 May 2010 20:32:02 GMT (13kb)

Title: Spin oscillations of the normal polarized Fermi gas at Unitarity

Authors: Alessio Recati and Sandro Stringari

Categories: cond-mat.quant-gas

Comments: 5 pages, 1 figure

\\

Using density functional theory in a time dependent approach we determine the

frequencies of the compressional modes of the normal phase of a Fermi gas at

unitarity as a function of its polarization. Our energy functional accounts for

the typical elastic deformations exhibited by Landau theory of Fermi liquids.

The comparison with the available experiments is biased by important

collisional effects affecting both the {\it in phase} and the {\it out of

phase} oscillations even at the lowest temperatures. New experiments in the

collisionless regime would provide a crucial test of the applicability of

Landau theory to the dynamics of these strongly interacting normal Fermi gases.

\\ ( http://arxiv.org/abs/1005.3040 , 13kb)

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arXiv:1005.3069

Date: Mon, 17 May 2010 22:35:12 GMT (1519kb)

Title: Open quantum systems approach to atomtronics

Authors: R. A. Pepino, J. Cooper, D. Meiser, D. Z. Anderson, and M. J. Holland

Categories: quant-ph physics.atom-ph

Comments: 10 pages, 10 figures, 1 table

\\

We derive a quantum master equation to treat quantum systems interacting with

multiple reservoirs. The formalism is used to investigate atomic transport

across a variety of lattice configurations. We demonstrate how the behavior of

an electronic diode, a field-effect transistor, and a bipolar junction

transistor can be realized with neutral, ultracold atoms trapped in optical

lattices. An analysis of the current fluctuations is provided for the case of

the atomtronic diode. Finally, we show that it is possible to demonstrate AND

logic gate behavior in an optical lattice.

\\ ( http://arxiv.org/abs/1005.3069 , 1519kb)

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arXiv:1005.3081

Date: Tue, 18 May 2010 00:53:26 GMT (1014kb,D)

Title: Fluctuations and correlations in rotating Bose-Einstein condensates

Authors: Soheil Baharian and Gordon Baym

Categories: cond-mat.quant-gas

\\

We investigate the effect of correlations on the properties of the ground

state of the rotating Bose gas when Bogoliubov fluctuations are added to the

mean-field ground state of a single-vortex system. We demonstrate that the

correlations induced by the fluctuations lower the energy compared to that of

the mean-field ground state, that the vortex acquires a finite (constant)

density at its core, and that an unstable mode with negative energy (for

rotations slower than a critical frequency) emerges in the energy spectrum

which points at a better state for slow rotation rates. We find, in the

mean-field picture, the critical rotation frequencies for transitions from the

0- to 1-vortex and from 1- to 2-vortex states and also the rotation frequency

for the appearance of a metastable state supporting an off-center vortex in the

cloud and its {\lq\lq}mirror{\rq\rq} vortex in the evanescent tail of the

cloud.

\\ ( http://arxiv.org/abs/1005.3081 , 1014kb)

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arXiv:1005.3090

Date: Tue, 18 May 2010 02:33:45 GMT (653kb)

Title: Domain wall dynamics in a two-component Bose-Mott insulator

Authors: Stefan S. Natu and Erich J. Mueller

Categories: cond-mat.quant-gas

Comments: 6 pages, 5 figures submitted to PRA

\\

We model the dynamics of two species of bosonic atoms trapped in an optical

lattice within the Mott regime by mapping the system onto a spin model. A field

gradient breaks the cloud into two domains. We study how the domain wall

evolves under adiabatic and diabatic changes of this gradient. We determine the

timescales for adiabaticity, and study how temperature evolves for slow ramps.

We show that after large, sudden changes of the field gradient, the system does

not equilibrate on typical experimental timescales. We find interesting spin

dynamics even when the initial temperature is large compared to the

super-exchange energy. We discuss the implication of our results for

experiments wishing to use such a two-component system for thermometry, or as

part of a cooling scheme.

\\ ( http://arxiv.org/abs/1005.3090 , 653kb)

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arXiv:1005.3117

Date: Tue, 18 May 2010 08:07:34 GMT (7kb)

Title: Effective Mass Schrodinger Equation via Point Canonical Transformation

Authors: Altug Arda and Ramazan Sever

Categories: quant-ph

Comments: 10 pages

\\

Exact solutions of effective radial Schr\"{o}dinger equation are obtained for

some inverse potentials by using the point canonical transformation. The energy

eigenvalues and the corresponding wave functions are calculated by using a set

of mass distributions

\\ ( http://arxiv.org/abs/1005.3117 , 7kb)

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arXiv:1005.3129

Date: Tue, 18 May 2010 09:45:19 GMT (664kb)

Title: Ab-initio phase diagram of ultracold 87-Rb in an one-dimensional

two-color superlattice

Authors: Felix Schmitt, Markus Hild, Robert Roth

Categories: cond-mat.quant-gas

Comments: 11 pages, 8 figures, 3 tables

\\

We investigate the ab-initio phase diagram of ultracold 87-Rb atoms in an

one-dimensional two-color superlattice. Using single-particle band structure

calculations we map the experimental setup onto the parameters of the

Bose-Hubbard model. This ab-initio ansatz allows us to express the phase

diagrams in terms of the experimental control parameters, i.e., the intensities

of the lasers that form the optical superlattice. In order to solve the

many-body problem for experimental system sizes we adopt the density-matrix

renormalization-group algorithm. A detailed study of convergence and

finite-size effects for all observables is presented. Our results show that all

relevant quantum phases, i.e., superfluid, Mott-insulator, and quasi

Bose-glass, can be accessed through intensity variation of the lasers alone.

However, it turns out that the phase diagram is strongly affected by the

longitudinal trapping potential.

\\ ( http://arxiv.org/abs/1005.3129 , 664kb)

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arXiv:1005.3141

Date: Tue, 18 May 2010 10:17:10 GMT (810kb,D)

Title: A BCS wavefunction approach to the BEC-BCS crossover of

exciton-polariton condensates

Authors: Tim Byrnes, Tomoyuki Horikiri, Natsuko Ishida, Yoshihisa Yamamoto

Categories: cond-mat.quant-gas cond-mat.mes-hall

Comments: 10 pages, 3 figures

\\

The crossover between low and high density regimes of exciton-polariton

condensates is examined using a BCS wavefunction approach. Our approach is an

extension of the BEC-BCS crossover theory for excitons, but includes a cavity

photon field. The approach can describe both the low density limit, where the

system can be described as a Bose-Einstein condensate (BEC) of

exciton-polaritons, and the high density limit, where the system enters a

photon dominated regime. In contrast to the exciton BEC-BCS crossover where the

system approaches an electron-hole plasma, the polariton high density limit has

strongly correlated electron-hole pairs. At intermediate densities, there is a

regime with BCS-like properties, with a peak at non-zero momentum of the

singlet pair function. We calculate the expected photoluminescence and give

several experimental signatures of the crossover.

\\ ( http://arxiv.org/abs/1005.3141 , 810kb)

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arXiv:1005.3152

Date: Tue, 18 May 2010 10:42:17 GMT (1281kb)

Title: Fiber-comb-stabilized light source at 556 nm for magneto-optical

trapping of ytterbium

Authors: Masami Yasuda, Takuya Kohno, Hajime Inaba, Yoshiaki Nakajima, Kazumoto

Hosaka, Atsushi Onae, and Feng-Lei Hong

Categories: physics.atom-ph physics.optics

Comments: 18 pages, 6 figures, submitted to and accepted by J. Opt. Soc. Am. B

(ID 125081)

Journal-ref: J. Opt. Soc. Am. B, 2010 (ID 125081)

\\

A frequency-stabilized light source emitting at 556 nm is realized by

frequency-doubling a 1112-nm laser, which is phase-locked to a fiber-based

optical frequency comb. The 1112-nm laser is either an ytterbium (Yb)-doped

distributed feedback fiber laser or a master-slave laser system that uses an

external cavity diode laser as a master laser. We have achieved the continuous

frequency stabilization of the light source over a five-day period. With the

light source, we have completed the second-stage magneto-optical trapping (MOT)

of Yb atoms using the 1S0 - 3P1 intercombination transition. The temperature of

the ultracold atoms in the MOT was 40 uK when measured using the time-of-flight

method, and this is sufficient for loading the atoms into an optical lattice.

The fiber-based frequency comb is shown to be a useful tool for controlling the

laser frequency in cold-atom experiments.

\\ ( http://arxiv.org/abs/1005.3152 , 1281kb)

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arXiv:1005.3167 (*cross-listing*)

Date: Tue, 18 May 2010 12:03:05 GMT (1463kb)

Title: Pipelike current-carrying vortices in two-component condensates

Authors: M.N. Chernodub and A.S. Nedelin

Categories: hep-th cond-mat.supr-con hep-ph

Comments: 11 pages, 14 figures, RevTex 4.1

Report-no: UUITP-20/10

\\

We study straight vortices with global longitudinal currents in the

Bogomol'ny limit of the Abelian Higgs model with two charged scalar fields. The

model possesses global SU(2) and local electromagnetic U(1) symmetries

spontaneously broken to global U(1) group, and corresponds to a semilocal limit

of the standard electroweak model. We show that the contribution of the global

SU(2) current to the vortex energy is proportional to the total current

squared. Locally, these vortices carry also longitudinal electromagnetic

currents, while the total electromagnetic current flowing through a transverse

section of the vortex is always zero. The vortices with high winding numbers

have, in general, a nested pipelike structure. The magnetic field of the vortex

is concentrated at a certain distance from the geometric center of the vortex,

thus resembling a ``pipe''. This magnetic pipe is layered between two

electrically charged pipes that carry longitudinal electric currents in

opposite directions.

\\ ( http://arxiv.org/abs/1005.3167 , 1463kb)

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arXiv:1005.3206

Date: Tue, 18 May 2010 14:23:12 GMT (511kb)

Title: Luttinger liquid in superlattice structures: atomic gases, quantum dots

and the classical Ising chain

Authors: Aranya B Bhattacherjee, Pradip Jha, Tarun Kumar and ManMohan

Categories: cond-mat.mes-hall

Comments: 7 figures

\\

We study physical properties of a Luttinger liquid in a superlattice which is

characterized by alternating two tunneling parameters. Employing the

Bosonization approach, we describe the corresponding Hubbard model by the

equivalent Tomonoga-Luttinger model. We analyze the spin-charge separation and

transport property as the difference between the two tunneling parameter

increases. We suggest that cold Fermi gases trapped in a bichromatic optical

lattice and coupled quantum dots offer the opportunity to measure these effects

in a convenient manner. We also study the classical Ising chain with two

tunneling parameters. We found that the classical two-point correlator

decreases as the difference between the two tunneling parameter increases.

\\ ( http://arxiv.org/abs/1005.3206 , 511kb)

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arXiv:1005.3239

Date: Tue, 18 May 2010 16:09:25 GMT (597kb)

Title: Competition between Normal Superfluidity and Larkin-Ovchinnikov Phases

of Polarized Fermi Gases in Elongated Traps

Authors: J.C. Pei, J. Dukelsky, W. Nazarewicz

Categories: cond-mat.quant-gas nucl-th

Comments: 4 pages, 4 figures

\\

By applying the recently proposed antisymmetric superfluid local density

approximation (ASLDA) to strongly interacting polarized atomic gases in

elongated traps, we predict clear signals of a type of Larkin-Ovchinnikov (LO)

phase that could be accessible by increasing adiabatically the trap aspect

ratio. We compare ASLDA with the Superfluid Local Density Approximation (SLDA),

previously introduced for unpolarized systems. In particular, we find that the

deformation of the superfluid core in distorted traps that appears in the

ground state solution of SLDA as well as in some Bogoliubov-de Gennes

treatments, is washed out in more realistic ASLDA calculations.

\\ ( http://arxiv.org/abs/1005.3239 , 597kb)

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arXiv:1005.3356

Date: Wed, 19 May 2010 03:39:28 GMT (164kb)

Title: Bounds for multipartite concurrence

Authors: Ming Li, Shao-Ming Fei and Zhi-Xi Wang

Categories: quant-ph

Comments: 8 pages

Journal-ref: Rep. Math. Phys. 65(2010)289-296

\\

We study the entanglement of a multipartite quantum state. An inequality

between the bipartite concurrence and the multipartite concurrence is obtained.

More effective lower and upper bounds of the multipartite concurrence are

obtained. By using the lower bound, the entanglement of more multipartite

states are detected.

\\ ( http://arxiv.org/abs/1005.3356 , 164kb)

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arXiv:1005.3372 (*cross-listing*)

Date: Wed, 19 May 2010 07:48:40 GMT (2238kb)

Title: Nanometer-scale spatial modulation of an inter-atomic interaction in a

Bose-Einstein condensate

Authors: Rekishu Yamazaki and Shintaro Taie and Seiji Sugawa and Yoshiro

Takahashi

Categories: physics.atom-ph cond-mat.quant-gas quant-ph

\\

We demonstrate nanometer-scale spatial control of inter-atomic interactions

in a Bose-Einstein condensate of ytterbium(Yb). A pulsed optical standing wave,

tuned near an optical Feshbach resonance varies the s-wave scattering length

continuously across the standing wave pattern. The modulated mean-field energy

with a spatial period of every 278 nm is monitored by a diffraction pattern in

a time-of-flight image. We observe a wide scattering length control of up to

160 nm. The demonstrated spatial modulation of the scattering length proves

that the high resolution control of atomic interactions is possible.

\\ ( http://arxiv.org/abs/1005.3372 , 2238kb)

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\\

arXiv:1005.3408 (*cross-listing*)

Date: Wed, 19 May 2010 10:40:24 GMT (8kb)

Title: Excitation of Quantized Longitudinal Electric Waves in a Degenerate

Fermi Gas

Authors: Levan N. Tsintsadze

Categories: physics.plasm-ph astro-ph.CO quant-ph

Comments: Submitted to Physical Review E

\\

The system of electron beam - degenerate Fermi gas in a magnetic field is

investigated. Instabilities of the quantized longitudinal electric waves are

studied by a newly derived dispersion equation. Novel branches of longitudinal

waves are found, which have no analogies without the Landau quantization.

Growth rates of these new modes are obtained. The excitation of the zero sound

by an electron beam is discussed and found that the quantization of the energy

of electrons imposes a new condition. Furthermore, the excitation of

Bogolyubov's type of spectrum by a strong electric field is considered.

\\ ( http://arxiv.org/abs/1005.3408 , 8kb)

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\\

arXiv:1005.3541

Date: Wed, 19 May 2010 20:00:36 GMT (36kb)

Title: Nonlinear resonant tunneling of Bose-Einstein condensates in tilted

optical lattices

Authors: K. Rapedius, C. Elsen, D. Witthaut, S. Wimberger, and H. J. Korsch

Categories: cond-mat.quant-gas quant-ph

Comments: 4 pages, 4 figures

\\

We study the tunneling decay of a Bose-Einstein condensate out of tilted

optical lattices within the mean-field approximation. We introduce a novel

method to calculate the resonance eigenstates of the Gross-Pitaevskii equation,

based on a grid relaxation procedure with complex absorbing potentials. This

algorithm works efficiently in a wide range of parameters where established

methods fail. It allows us to study the effects of the nonlinearity in detail

in the regime of resonant tunneling, where the decay rate is enhanced by

resonant coupling to excited unstable states.

\\ ( http://arxiv.org/abs/1005.3541 , 36kb)

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\\

arXiv:1005.3557

Date: Wed, 19 May 2010 20:48:28 GMT (86kb)

Title: Observing Monopoles in a Magnetic Analog of Ice

Authors: Michel J.P. Gingras

Categories: cond-mat.other

Comments: 3 pages, 1 figure

Journal-ref: Science 326, 375 (2009)

DOI: 10.1126/science.1181510

\\

This is a nontechnical Perspective commentary on two recent neutron

scattering experiments (Science 326, 415 (2009) and Science 326, 411 (2009))

reporting evidence for the validity of a "Coulomb phase" description of the

low-temperature regime of frustrated spin ice magnetic materials as well as the

existence of topological defect (monopole-like) excitations in these systems.

\\ ( http://arxiv.org/abs/1005.3557 , 86kb)

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\\

arXiv:1005.3576

Date: Thu, 20 May 2010 01:50:28 GMT (153kb)

Title: Thermodynamic properties of two-component fermionic atoms trapped in a

two-dimensional optical lattice

Authors: Kensuke Inaba and Makoto Yamashita

Categories: cond-mat.quant-gas

Comments: 9 pages, 13 figures

\\

We study the finite temperature properties of two-component fermionic atoms

trapped in a two-dimensional optical lattice. We apply the self-energy

functional approach to the two-dimensional Hubbard model with a harmonic

trapping potential, and systematically investigate the thermodynamic properties

of this system. We find that entropy and grand potential provide evidence of a

crossover between the Mott insulating and metallic phases at certain

temperatures. In addition, we find that entropy exhibits a cusp-like anomaly at

lower temperatures, suggesting a second or higher order antiferromagnetic

transition. We estimate the antiferromagnetic transition temperatures, and

clarify how the trapping potential affects this magnetic transition.

\\ ( http://arxiv.org/abs/1005.3576 , 153kb)

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\\

arXiv:1005.3628

Date: Thu, 20 May 2010 08:39:11 GMT (48kb)

Title: When a DNA Triple helix melts: An analog of the Efimov state

Authors: Jaya Maji, Somendra M. Bhattacharjee, Flavio Seno and A. Trovatto

Categories: cond-mat.soft cond-mat.stat-mech nucl-th

Comments: 7 pages, 8 figures

\\

The base sequences of DNA contain the genetic code and to decode it a double

helical DNA has to open its base pairs. Last several years' studies have shown

that one can use a third strand to identify the base sequences without opening

the double helix but by forming a triple helix. It is predicted here that such

a three chain system exhibits the unusual behaviour of the existence of a three

chain bound state in the absence of any two being bound. This phenomenon is

analogous to the Efimov state in three particle quantum mechanics. A scaling

theory is used to justify the Efimov connection. Real space renormalization

group (RG), and exact numerical calculations are used to validate the

prediction of a biological Efimov effect.

\\ ( http://arxiv.org/abs/1005.3628 , 48kb)

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\\

arXiv:1005.3641

Date: Thu, 20 May 2010 09:37:30 GMT (110kb)

Title: Correlations and superfluidity of a one-dimensional Bose gas in a

quasiperiodic potential

Authors: Alberto Cetoli and Emil Lundh

Categories: cond-mat.dis-nn

Comments: Accepted for publication in PRA

\\

We consider the correlations and superfluid properties of a Bose gas in an

external potential. Using a Bogoliubov scheme, we obtain expressions for the

correlation function and the superfluid density in an arbitrary external

potential. These expressions are applied to a one-dimensional system at zero

temperature subject to a quasiperiodic modulation. The critical parameters for

the Bose glass transition are obtained using two different criteria and the

results are compared. The Lifshits glass is seen to be the limiting case for

vanishing interactions.

\\ ( http://arxiv.org/abs/1005.3641 , 110kb)

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\\

arXiv:1005.3660

Date: Thu, 20 May 2010 11:16:42 GMT (164kb)

Title: Lieb-Liniger gas in a constant force potential

Authors: D. Juki\'c, S. Gali\'c, R. Pezer, H. Buljan

Categories: cond-mat.quant-gas quant-ph

\\

We use Gaudin's Fermi-Bose mapping operator to calculate exact solutions for

the Lieb-Liniger model in a linear (constant force) potential (the constructed

exact stationary solutions are referred to as the Lieb-Liniger-Airy wave

functions). The ground state properties of the gas in the wedge-like trapping

potential are calculated in the strongly interacting regime by using

Girardeau's Fermi-Bose mapping and the pseudopotential approach in the

$1/c$-approximation ($c$ denotes the strength of the interaction). We point out

that quantum dynamics of Lieb-Liniger wave packets in the linear potential can

be calculated by employing an $N$-dimensional Fourier transform as in the case

of free expansion.

\\ ( http://arxiv.org/abs/1005.3660 , 164kb)

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\\

arXiv:1005.3670

Date: Thu, 20 May 2010 11:49:46 GMT (781kb)

Title: Realization of SU(2)*SU(6) Fermi System

Authors: Shintaro Taie, Yosuke Takasu, Seiji Sugawa, Rekishu Yamazaki, Takuya

Tsujimoto, Ryo Murakami, Yoshiro Takahashi

Categories: cond-mat.quant-gas physics.atom-ph

Comments: 4 pages, 5 figures

\\

We report the realization of a novel degenerate Fermi mixture with an

SU(2)*SU(6) symmetry in a cold atomic gas. We successfully cool the mixture of

the two fermionic isotopes of ytterbium 171Yb with the nuclear spin I=1/2 and

173Yb with I=5/2 below the Fermi temperature T_ F as 0.46T_F for 171Yb and

0.54T_F for 173Yb. The same scattering lengths for different spin components

make this mixture featured with the novel SU(2)*SU(6) symmetry. The nuclear

spin components are separately imaged by exploiting an optical Stern-Gerlach

effect. In addition, the mixture is loaded into a 3D optical lattice to

implement the SU(2)*SU(6) Hubbard model. This mixture will open the door to the

study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like

fermionic superfluid.

\\ ( http://arxiv.org/abs/1005.3670 , 781kb)

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\\

arXiv:1005.3725

Date: Thu, 20 May 2010 15:01:46 GMT (608kb)

Title: Off-axis Vortex in a Rotating Dipolar Bose-Einstein Condensation

Authors: C. Yuce, Z. Oztas

Categories: cond-mat.quant-gas

Comments: Journal of Physics B (to be published); 9 pages; 6 Figures

\\

We consider a singly quantized off-axis straight vortex in a rotating dipolar

ultracold gas in the Thomas-Fermi (TF) regime. We derive analytic results for

small displacements and perform numerical calculations for large displacement

within the TF regime. We show that the dipolar interaction energy increases

(decreases) as the vortex moves from the trap center to the edge in an oblate

(a prolate) trap. We find that for an oblate (a prolate) trap, the effect of

the dipole-dipole interaction is to lower (raise) both the precession velocity

of an off-center straight vortex line and the angular velocity representing the

onset of metastability.

\\ ( http://arxiv.org/abs/1005.3725 , 608kb)

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\\

arXiv:1005.3789

Date: Thu, 20 May 2010 18:55:29 GMT (2959kb)

Title: Dynamics of Dark-Bright Solitons in Cigar-Shaped Bose-Einstein

Condensates

Authors: S. Middelkamp, J.J. Chang, C. Hamner, R. Carretero-Gonzalez, P.G.

Kevrekidis, V. Achilleos, D.J. Frantzeskakis, P. Schmelcher, P. Engels

Categories: cond-mat.quant-gas

Comments: 4 pages, 5 figures

\\

We explore the stability and dynamics of dark-bright solitons in

two-component elongated Bose-Einstein condensates by developing effective 1D

vector equations as well as solving the corresponding 3D Gross-Pitaevskii

equations. A strong dependence of the oscillation frequency and of the

stability of the dark-bright (DB) soliton on the atom number of its components

is found. Spontaneous symmetry breaking leads to oscillatory dynamics in the

transverse degrees of freedom for a large occupation of the component

supporting the dark soliton. Moreover, the interactions of two DB solitons are

investigated with special emphasis on the importance of their relative phases.

Experimental results showcasing dark-bright soliton dynamics and collisions in

a BEC consisting of two hyperfine states of $^{87}$Rb confined in an elongated

optical dipole trap are presented.

\\ ( http://arxiv.org/abs/1005.3789 , 2959kb)

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The replacements:

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\\

arXiv:0904.3221

replaced with revised version Tue, 18 May 2010 10:06:59 GMT (197kb)

Title: Exact methods in analysis of nonequilibrium dynamics of integrable

models: application to the study of correlation functions in nonequilibrium

1D Bose gas

Authors: Vladimir Gritsev, Timofei Rostunov, Eugene Demler

Categories: cond-mat.quant-gas cond-mat.other math-ph math.MP quant-ph

Comments: 27 pages, 7 figures, minor corrections, refs added

Journal-ref: J. Stat. Mech. (2010) P05012

DOI: 10.1088/1742-5468/2010/05/P05012

\\ ( http://arxiv.org/abs/0904.3221 , 197kb)

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\\

arXiv:0907.2906

replaced with revised version Mon, 17 May 2010 19:54:23 GMT (882kb)

Title: Anharmonicity Induced Resonances for Ultracold Atoms and their Detection

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

Categories: cond-mat.quant-gas

Comments: 6 pages, 5 figures; expanded presentation

Journal-ref: New J. Phys. 12, 053016 (2010)

DOI: 10.1088/1367-2630/12/5/053016

\\ ( http://arxiv.org/abs/0907.2906 , 882kb)

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\\

arXiv:0910.1749 (*cross-listing*)

replaced with revised version Fri, 14 May 2010 13:48:33 GMT (187kb)

Title: Fermionization dynamics of a strongly interacting 1D Bose gas after an

interaction quench

Authors: Dominik Muth, Bernd Schmidt, and Michael Fleischhauer

Categories: quant-ph cond-mat.quant-gas

Comments: 10 pages, 4 figures

\\ ( http://arxiv.org/abs/0910.1749 , 187kb)

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\\

arXiv:0910.1859

replaced with revised version Fri, 14 May 2010 08:02:16 GMT (622kb,D)

Title: Observability of Quantum Criticality and a Continuous Supersolid in

Atomic Gases

Authors: S. Diehl, M. Baranov, A. J. Daley, P. Zoller

Categories: cond-mat.quant-gas

Comments: 4 pages, 2 figures, published version (Editor's suggestion)

Journal-ref: Phys. Rev. Lett. 104, 165301 (2010)

DOI: 10.1103/PhysRevLett.104.165301

\\ ( http://arxiv.org/abs/0910.1859 , 622kb)

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\\

arXiv:0912.3502

replaced with revised version Thu, 20 May 2010 15:22:34 GMT (87kb,D)

Title: 1D Lieb-Liniger Bose Gas as Non-Relativistic Limit of the Sinh-Gordon

Model

Authors: M. Kormos, G. Mussardo, A. Trombettoni

Categories: cond-mat.stat-mech cond-mat.quant-gas hep-th

Comments: published version, 27 pages, 10 figures

Journal-ref: Phys.Rev.A81:043606,2010

DOI: 10.1103/PhysRevA.81.043606

\\ ( http://arxiv.org/abs/0912.3502 , 87kb)

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\\

arXiv:1002.0552

replaced with revised version Thu, 20 May 2010 07:35:44 GMT (622kb)

Title: Dark solitons in cigar-shaped Bose-Einstein condensates in double-well

potentials

Authors: S. Middelkamp, G. Theocharis, P.G. Kevrekidis, D.J. Frantzeskakis, P.

Schmelcher

Categories: cond-mat.quant-gas

Comments: 35 pages, 12 figures

Journal-ref: Phys. Rev. A 81, 053618 (2010)

DOI: 10.1103/PhysRevA.81.053618

\\ ( http://arxiv.org/abs/1002.0552 , 622kb)

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\\

arXiv:1003.0387

replaced with revised version Thu, 20 May 2010 02:00:45 GMT (1528kb)

Title: Vortex dynamics in superconducting channels with periodic constrictions

Authors: K. Yu (1), M.B.S. Hesselberth (2), P.H. Kes (2), B.L.T. Plourde (1)

((1) Department of Physics, Syracuse University, (2) Kamerlingh Onnes

Laboratorium, Leiden University)

Categories: cond-mat.supr-con

Journal-ref: Phys. Rev. B 81, 184503 (2010)

DOI: 10.1103/PhysRevB.81.184503

\\ ( http://arxiv.org/abs/1003.0387 , 1528kb)

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\\

arXiv:1004.1966

replaced with revised version Tue, 18 May 2010 09:45:37 GMT (152kb,D)

Title: Influence of the particle number on the spin dynamics of ultracold atoms

Authors: Jannes Heinze, Frank Deuretzbacher and Daniela Pfannkuche

Categories: cond-mat.quant-gas

\\ ( http://arxiv.org/abs/1004.1966 , 152kb)

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\\

arXiv:1004.3969

replaced with revised version Thu, 20 May 2010 14:48:46 GMT (192kb)

Title: EIT-based Vector Magnetometry in Linear Polarized Light

Authors: V. I. Yudin, A. V. Taichenachev, Y. I. Dudin, V. L. Velichansky, A. S.

Zibrov, S. A. Zibrov

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

Comments: 8 pages, 7 figures

\\ ( http://arxiv.org/abs/1004.3969 , 192kb)

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\\

arXiv:1005.1812

replaced with revised version Tue, 18 May 2010 09:19:32 GMT (0kb,I)

Title: Absence of pairing in atomic Fermi gases

Authors: J. J. Kinnunen

Categories: cond-mat.quant-gas quant-ph

Comments: The draft paper has been withdrawn by the author

\\ ( http://arxiv.org/abs/1005.1812 , 0kb)

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\\

arXiv:1005.2403

replaced with revised version Fri, 14 May 2010 17:42:50 GMT (477kb,D)

Title: A superfluid-droplet crystal and a free-space supersolid in a

dipole-blockaded gas

Authors: F. Cinti, P. Jain, M. Boninsegni, A. Micheli, P. Zoller, and G.

Pupillo

Categories: cond-mat.quant-gas cond-mat.stat-mech

Comments: 4 pages, 4 figures

\\ ( http://arxiv.org/abs/1005.2403 , 477kb)

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\\

arXiv:cond-mat/0703498

replaced with revised version Wed, 19 May 2010 05:23:56 GMT (98kb)

Title: Re-examining Bogoliubov's theory of an interacting Bose gas

Authors: A.M. Ettouhami

Categories: cond-mat.stat-mech cond-mat.other cond-mat.quant-gas

Comments: Major revision of version 1; 41 pages, 16 figures

\\ ( http://arxiv.org/abs/cond-mat/0703498 , 98kb)

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Till next time,

Matt.

-- ========================================================================= Dr M. J. Davis, Associate Professor in Physics School of Mathematics and Physics, ph : +61 7 334 69824 The University of Queensland, fax : +61 7 336 51242 Brisbane, QLD 4072, mdavis_at_physics.uq.edu.au Australia. www.physics.uq.edu.au/people/mdavis/ ========================================================================= Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/ ========================================================================= Legal stuff: Unless stated otherwise, this e-mail represents only the views of the sender and not the views of the University of Queensland ========================================================================= _______________________________________________ Matts-arxiv mailing list Matts-arxiv_at_lists.sps.uq.edu.auReceived on Wed Aug 04 2010 - 09:31:28 EST

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