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

Date: Thu, 10 Jun 2010 15:44:36 +1000

Date: Thu, 10 Jun 2010 15:44:36 +1000

Dear subscribers,

Thanks for all the supportive emails. I will be continuing Matt's arXiv and

have set up a schedule in order to try to keep up to date. We should be back on

track in the next week.

This week's selection was compiled by Geoff Lee, and contains 29 new abstracts

and 12 replacements.

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arXiv:0910.0052 (*cross-listing*)

Date: Wed, 30 Sep 2009 23:17:56 GMT (263kb)

Date (revised v2): Mon, 10 May 2010 18:51:05 GMT (264kb)

Title: Stability of a Fully Polarized Ultracold Fermi Gas near Zero-Crossing of

a p-wave Feshbach Resonance

Authors: N. T. Zinner

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

Comments: Published version, 6 pages, 2 figures

Journal-ref: Eur. Phys. J. D 57, 235 (2010)

DOI: 10.1140/epjd/e2010-00047-2

\\

We consider a fully polarized ultracold Fermi gas interacting through a

p-wave Feshbach resonance. Using a two-channel model, we find the effective

potential at the point where the p-wave scattering length goes to zero. Here

the effective interaction provides attraction and one can therefore ask about

the stability of the system. We calculate the energy density of the system in

the Thomas-Fermi approximation, determine the profile of the gas, and the

critical number of particle in the system as function of the relevant

interaction parameters. The instability can be deduced from a simple breathing

mode argument which explains the scaling found numerically. The critical

particle number turns out to be extremely large unless the external confinement

is very tight. We therefore conclude that the effect is insignificant for

standard trapping potentials and that the magnetic dipole interaction is the

important term at zero scattering length. However, for tight confinement as in

an optical lattice higher-order corrections can become important.

\\ ( http://arxiv.org/abs/0910.0052 , 264kb)

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arXiv:1001.3250 (*cross-listing*)

Date: Tue, 19 Jan 2010 13:27:10 GMT (982kb)

Date (revised v2): Tue, 11 May 2010 18:21:02 GMT (985kb)

Title: Three-dimensional Roton-Excitations and Supersolid formation in

Rydberg-excited Bose-Einstein Condensates

Authors: N. Henkel, R. Nath, T. Pohl

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

Comments: 4 pages, 5 figures

Journal-ref: Phys. Rev. Lett. 104, 195302 (2010)

DOI: 10.1103/PhysRevLett.104.195302

\\

We study the behavior of a Bose-Einstein condensate in which atoms are weakly

coupled to a highly excited Rydberg state. Since the latter have very strong

van der Waals interactions, this coupling induces effective, nonlocal

interactions between the dressed ground state atoms, which, opposed to dipolar

interactions, are isotropically repulsive. Yet, one finds partial attraction in

momentum space, giving rise to a roton-maxon excitation spectrum and a

transition to a supersolid state in three-dimensional condensates. A detailed

analysis of decoherence and loss mechanisms suggests that these phenomena are

observable with current experimental capabilities.

\\ ( http://arxiv.org/abs/1001.3250 , 985kb)

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arXiv:1005.1138

Date: Fri, 7 May 2010 06:11:11 GMT (682kb,D)

Title: Manipulation of coherent atom waves using accelerated two-dimensional

optical lattices

Authors: Wei-Chih Ting, Dian-Jiun Han, and Shin-Tza Wu

Categories: cond-mat.quant-gas

Comments: Figures with low resolution; high quality ones can be supplied on

request

\\

We study the dynamics of Bose-Einstein condensates in accelerated

two-dimensional optical square lattices by numerically solving the

Gross-Pitaevskii equation. We consider the regime with negligible mean-field

interactions and examine in detail the pulses of atom clouds ejected from the

condensate due to Landau-Zener tunnelling. The pulses exhibit patterned

structures that can be understood from the momentum-space dynamics of the

condensate. Aside from conceiving realization of a pulsed two-dimensional atom

laser, we demonstrate that, by exploring the band structure of the lattice,

Landau-Zener tunnelling and Bragg reflection of the condensate inside the

optical lattice can provide means for manipulation of coherent atom waves. This

result shall be valuable for beam splitting in atom interferometry and possibly

also for quantum information sciences.

\\ ( http://arxiv.org/abs/1005.1138 , 682kb)

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arXiv:1005.1158

Date: Fri, 7 May 2010 08:58:56 GMT (23kb)

Title: Temperature and coupling dependence of the "contact" for an ultracold

Fermi gas

Authors: F. Palestini, A. Perali, P. Pieri, G. C. Strinati

Categories: cond-mat.quant-gas

Comments: 4 pages, 3 figures

\\

Physical properties of an ultracold Fermi gas in the temperature-coupling

phase diagram can be characterized by the "contact" C, which enters the

pair-correlation function at short distances and describes how the two-body

problem merges into its surrounding. We show that the local order established

by pairing fluctuations about the critical temperature Tc of the superfluid

transition considerably enhances the contact C in a temperature range where

pseudogap phenomena are maximal. Our results for C in a trap compare well with

recently available experimental data. A detailed analysis is also provided for

the effects that trap averaging has on the values of C.

\\ ( http://arxiv.org/abs/1005.1158 , 23kb)

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arXiv:1005.1190 (*cross-listing*)

Date: Fri, 7 May 2010 12:14:23 GMT (8kb)

Title: Stochastic process behind nonlinear thermodynamic quantum master

equation

Authors: Hans Christian \"Ottinger

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

Comments: 4 pages

\\

We propose a piecewise deterministic Markovian jump process in Hilbert space

such that the covariance matrix of this stochastic process solves the

thermodynamic quantum master equation. The proposed stochastic process is

particularly simple because the normalization of the vectors in Hilbert space

is preserved only on average. As a consequence of the nonlinearity of the

thermodynamic master equation, the construction of stochastic trajectories

involves the density matrix as a running ensemble average. We identify a

principle of detailed balance and a fluctuation-dissipation relation for our

Markovian jump process.

\\ ( http://arxiv.org/abs/1005.1190 , 8kb)

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arXiv:1005.1262

Date: Fri, 7 May 2010 17:41:46 GMT (3011kb)

Title: Vortex Dynamics in Anisotropic Traps

Authors: S. McEndoo and Th. Busch

Categories: cond-mat.quant-gas

Comments: 6 pages, 6 figures

\\

We investigate the dynamics of linear vortex lattices in anisotropic traps in

two-dimensions and show that the interplay between the rotation and the

anisotropy leads to a rich but highly regular dynamics.

\\ ( http://arxiv.org/abs/1005.1262 , 3011kb)

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arXiv:1005.1270

Date: Fri, 7 May 2010 18:19:52 GMT (70kb)

Title: Supersolid and charge density-wave states from anisotropic interaction

in an optical lattice

Authors: Y.-H. Chan, Y.-J. Han, L.-M. Duan

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

Comments: 5 pages, 5 figures.

\\

We show anisotropy of the dipole interaction between magnetic atoms or polar

molecules can stabilize new quantum phases in an optical lattice. Using a well

controlled numerical method based on the tensor network algorithm, we calculate

phase diagram of the resultant effective Hamiltonian in a two-dimensional

square lattice - an anisotropic Hubbard model of hard-core bosons with

attractive interaction in one direction and repulsive interaction in the other

direction. Besides the conventional superfluid and the Mott insulator states,

we find the striped and the checkerboard charge density wave states and the

supersolid phase that interconnect the superfluid and the striped solid states.

The transition to the supersolid phase has a mechanism different from the case

of the soft-core Bose Hubbard model.

\\ ( http://arxiv.org/abs/1005.1270 , 70kb)

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arXiv:1005.1276

Date: Fri, 7 May 2010 19:09:35 GMT (8098kb,D)

Title: Multi-Component Quantum Gases in Spin-Dependent Hexagonal Lattices

Authors: Parvis Soltan-Panahi, Julian Struck, Philipp Hauke, Andreas Bick,

Wiebke Plenkers, Georg Meineke, Christoph Becker, Patrick Windpassinger,

Maciej Lewenstein, and Klaus Sengstock

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

Comments: 9 pages, 5 figures

\\

Periodicity is one of the most fundamental structural characteristics of

systems occurring in nature. The properties of these systems depend strongly on

the symmetry of the underlying periodic structure. In solid state materials -

for example - the static and transport properties as well as the magnetic and

electronic characteristics are crucially influenced by the crystal symmetry. In

this context, hexagonal structures play an extremely important role and lead to

novel physics like that of carbon nanotubes or graphene. Here we report on the

first realization of ultracold atoms in a spin-dependent optical lattice with

hexagonal symmetry. We show how combined effects of the lattice and

interactions between atoms lead to a forced antiferromagnetic N\'eel order when

two spin-components localize at different lattice sites. We also demonstrate

that the coexistence of two components - one Mott-insulating and the other one

superfluid - leads to the formation of a forced supersolid. Our observations

are consistent with theoretical predictions using Gutzwiller mean-field theory.

\\ ( http://arxiv.org/abs/1005.1276 , 8098kb)

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arXiv:1005.1309

Date: Fri, 7 May 2010 23:18:54 GMT (1081kb)

Title: Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

Authors: Christian Sanner, Edward J. Su, Aviv Keshet, Ralf Gommers, Yong-il

Shin, Wujie Huang, Wolfgang Ketterle

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

\\

We study density profiles of an ideal Fermi gas and observe Pauli suppression

of density fluctuations for cold clouds deep in the quantum degenerate regime.

Strong suppression of shot noise was observed for probe volumes containing more

than 10,000 atoms. Atom noise provides sensitive thermometry at low

temperatures. The Poissonian noise of a hot cloud provides a direct and

accurate calibration of the optical resolution and absorption cross section.

After this method of sensitive noise measurements has been validated with an

ideal Fermi gas, it can now be applied to characterize phase transitions in

strongly correlated many-body systems.

\\ ( http://arxiv.org/abs/1005.1309 , 1081kb)

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arXiv:1005.1363

Date: Sun, 9 May 2010 04:19:37 GMT (20kb)

Title: A Composite Fermion Approach to the Ultracold Dilute Fermi Gas

Authors: M. A. Cazalilla

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

Comments: 9 pages, no figures

\\

It is argued that the recently observed Fermi liquids in strongly interacting

ultracold Fermi gases are adiabatically connected to a projected Fermi gas.

This conclusion is reached by constructing a set of Jastrow wavefunctions,

following Tan's observations on the structure of the physical Hilbert space

[Annals of Physics 323, 2952 (2008)]. The Jastrow projection merely implements

the Bethe-Peierls condition on the BCS and Fermi gas wavefunctions. This

procedure provides a simple picture of the emergence of Fermi polarons as

composite fermions in the normal state of the highly polarized gas. It is also

shown that the projected BCS wavefunction can be written as a condensate of

pairs of composite fermions (or Fermi polarons). A Hamiltonian for the

composite fermions is derived. Within a mean-field theory, it is shown that the

ground state and excitations of this Hamiltonian are those of a non-interacting

Fermi gas although they are described by Jastrow-Slater wavefunctions.

\\ ( http://arxiv.org/abs/1005.1363 , 20kb)

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arXiv:1005.1399

Date: Sun, 9 May 2010 14:07:28 GMT (33kb)

Title: Simulating Wess-Zumino Supersymmetry Model in Optical Lattices

Authors: Yue Yu and Kun Yang

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

Comments: 4 pages, 1 figure

\\

We study a cold atom-molecule mixture in two-dimensional optical lattices, in

which fermionic atoms have a Dirac-type dispersion. We show that by fine-tuning

the atomic and molecular interactions, such mixtures can simulate Wess-Zumino

supersymmetry (SUSY) model, the first example of SUSY theories. At zero

temperature, SUSY is not spontaneously broken for this simplest SUSY model,

which implies identical relativistic dispersions of the atom and its

superpartner, bosonic diatom molecule. This defining signature of SUSY can be

probed by single particle spectroscopies. Thermal breaking of SUSY at finite

temperature is accompanied by a thermal Goldstone fermion, i.e., phonino

excitation. This and other signatures of broken SUSY can also be probed

experimentally.

\\ ( http://arxiv.org/abs/1005.1399 , 33kb)

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arXiv:1005.1436

Date: Mon, 10 May 2010 02:15:12 GMT (785kb)

Title: Light trapping in high-density ultracold atomic gases for quantum memory

applications

Authors: I.M. Sokolov, D.V. Kupriyanov, R.G. Olave, and M.D. Havey

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

Comments: Submitted to Journal of Modern Optics, Special 2010 PQE Issue

\\

High-density and ultracold atomic gases have emerged as promising media for

storage of individual photons for quantum memory applications. In this paper we

provide an overview of our theoretical and experimental efforts in this

direction, with particular attention paid to manipulation of light storage (a)

through complex recurrent optical scattering processes in very high density

gases (b) by an external control field in a characteristic electromagnetically

induced transparency configuration.

\\ ( http://arxiv.org/abs/1005.1436 , 785kb)

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arXiv:1005.1549

Date: Fri, 7 May 2010 07:59:45 GMT (12kb)

Title: Onset Properties of Supersolid Helium

Authors: Yongle Yu

Categories: cond-mat.supr-con

Comments: 3 pages, 2 fiugres

\\

Supersolid helium has a rather low transition temperature and a small

critical velocity, compared with liquid helium. These properties could be

explained in terms of helium's spectrum structure and quantum jumps involving

large momentum transfer. A grain in the solid helium possess valleys (local

minima) in its many-body dispersion curve, and an exchange of large momenta

with the grain's surroundings occurs in a jump between a level in one valley

and another level in the neighboring valley. Such jump process also naturally

causes dissipation accompanying the onset of supersolidity.

\\ ( http://arxiv.org/abs/1005.1549 , 12kb)

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arXiv:1005.1562

Date: Mon, 10 May 2010 14:28:24 GMT (108kb)

Title: Entangling two Bose Einstein condensates in a double cavity system

Authors: Tarun Kumar, Aranya B Bhattacherjee and ManMohan

Categories: cond-mat.quant-gas

Comments: 3 figures

\\

We propose a scheme to transfer the quantum state of light fields to the

collective density excitations of a Bose Einstein condensate (BEC) in a cavity.

This scheme allows to entangle two BECs in a double cavity setup by

transferring the quantum entanglement of two light fields produced from a

nondegenerate parametric amplifier (NOPA) to the collective density excitations

of the two BECs. An EPR state of the collective density excitations can be

created by a judicious choice of the system parameters.

\\ ( http://arxiv.org/abs/1005.1562 , 108kb)

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arXiv:1005.1812

Date: Tue, 11 May 2010 12:15:48 GMT (689kb,D)

Title: Absence of pairing in atomic Fermi gases

Authors: J. J. Kinnunen

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

Comments: Not submitted to any journal. Manuscript sent here for peer preview.

All questions, comments, and critique highly appreciated.

\\

Pairing of atoms is a central paradigm in the studies of ultracold Fermi

atomic gases. For a gas with attractive interactions, the pairing comes in the

form of BCS pairing in the superfluid phase or as preformed pairs in the

pseudogap phase, and as formation of molecules in the presence of two-body

bound states. In this work I show that the main experiments used for measuring

the pair binding energy in atomic Fermi gases can be easily explained using a

theory which makes no reference to bound pairs of atoms.

\\ ( http://arxiv.org/abs/1005.1812 , 689kb)

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arXiv:1005.1872

Date: Tue, 11 May 2010 16:00:43 GMT (202kb)

Title: Nonequilibrium dynamical mean-field calculations based on the

non-crossing approximation and its generalizations

Authors: Martin Eckstein and Philipp Werner

Categories: cond-mat.str-el

Comments: 14 pages, 9 figures

\\

We solve the impurity problem which arises within nonequilibrium dynamical

mean-field theory for the Hubbard model by means of a self-consistent

perturbation expansion around the atomic limit. While the lowest order, known

as the non-crossing approximation (NCA), is reliable only when the interaction

U is much larger than the bandwidth, low-order corrections to the NCA turn out

to be sufficient to reproduce numerically exact Monte Carlo results in a wide

parameter range that covers the insulating phase and the metal-insulator

crossover regime at not too low temperatures. As an application of the

perturbative strong-coupling impurity solver we investigate the response of the

double occupancy in the Mott insulating phase of the Hubbard model to a

dynamical change of the interaction or the hopping, a technique which has been

used as a probe of the Mott insulating state in ultracold fermionic gases.

\\ ( http://arxiv.org/abs/1005.1872 , 202kb)

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arXiv:1005.1897

Date: Tue, 11 May 2010 17:57:09 GMT (1724kb)

Title: Single vortex-antivortex pair in an exciton polariton condensate

Authors: Georgios Roumpos, Michael D. Fraser, Andreas L\"offler, Sven

H\"ofling, Alfred Forchel and Yoshihisa Yamamoto

Categories: cond-mat.quant-gas

\\

In a homogeneous two-dimensional system at non-zero temperature, although

there can be no ordering of infinite range, a superfluid phase is predicted for

a Bose liquid. The stabilization of phase in this superfluid regime is achieved

by the formation of bound vortex-antivortex pairs. It is believed that several

different systems share this common behaviour, when the parameter describing

their ordered state has two degrees of freedom, and the theory has been tested

for some of them. However, there has been no direct experimental observation of

the phase stabilization mechanism by a bound pair. Here we present an

experimental technique that can identify a single vortex-antivortex pair in a

two-dimensional exciton polariton condensate. The pair is generated by the

inhomogeneous pumping spot profile, and is revealed in the time-integrated

phase maps acquired using Michelson interferometry, which show that the

condensate phase is only locally disturbed. Numerical modelling based on open

dissipative Gross-Pitaevskii equation suggests that the pair evolution is quite

different in this non-equilibrium system compared to atomic condensates. Our

results demonstrate that the exciton polariton condensate is a unique system

for studying two-dimensional superfluidity in a previously inaccessible regime.

\\ ( http://arxiv.org/abs/1005.1897 , 1724kb)

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arXiv:1005.1906

Date: Tue, 11 May 2010 18:38:38 GMT (93kb)

Title: Reentrant transition of bosons in a quasiperiodic potential

Authors: A. Cetoli, E. Lundh

Categories: cond-mat.quant-gas

Comments: Accepted for publication in EPL

\\

We investigate the behavior of a two dimensional array of Bose-Einstein

condensate tubes described by means of a Bose-Hubbard Hamiltonian. Using a

Wannier function expansion for the wavefunction in each tube, we compute the

Bose-Hubbard parameters related to two different longitudinal potentials,

periodic and quasiperiodic. We predict that - upon increasing the external

potential strength along the direction of the tubes - the condensate can

experience a reentrant transition between a Mott insulating phase and the

superfluid one.

\\ ( http://arxiv.org/abs/1005.1906 , 93kb)

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arXiv:1005.1915

Date: Tue, 11 May 2010 19:17:08 GMT (552kb)

Title: Analytical and numerical study of trapped strongly correlated bosons in

two- and three-dimensional lattices

Authors: Itay Hen and Marcos Rigol

Categories: cond-mat.quant-gas

Comments: 14 pages, 14 figures.

\\

We study the ground-state properties of trapped inhomogeneous systems of

hardcore bosons in two- and three-dimensional lattices. We obtain our results

both numerically, using quantum Monte Carlo techniques, and via several

analytical approximation schemes, such as the Gutzwiller-mean-field approach, a

cluster-mean-field method and a spin-wave analysis which takes quantum

fluctuations into account. We first study the homogeneous case, for which

simple analytical expressions are obtained for all observables of interest, and

compare the results with the numerical ones. We obtain the equation of state of

the system along with other thermodynamic properties such as the free energy,

kinetic energy, superfluid density, condensate fraction and compressibility. In

the presence of a trap, superfluid and insulating domains coexist in the

system. We show that the spin-wave-based method reproduces the quantum

Monte-Carlo results for global as well as for local quantities with a high

degree of accuracy. We also discuss the validity of the local density

approximation in those systems. Our analysis can be used to describe bosons in

optical lattices where the onsite interaction U is much larger than the hopping

amplitude t.

\\ ( http://arxiv.org/abs/1005.1915 , 552kb)

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arXiv:1005.1922

Date: Tue, 11 May 2010 19:52:51 GMT (1781kb,D)

Title: Enhanced and reduced atom number fluctuations in a BEC splitter

Authors: Kenneth Maussang, G. Edward Marti, Tobias Schneider, Philipp

Treutlein, Yun Li, Alice Sinatra, Romain Long, J\'er\^ome Est\`eve, Jakob

Reichel

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

\\

We measure atom number statistics after splitting a gas of ultracold 87Rb

atoms in a purely magnetic double-well potential created on an atom chip. Well

below the critical temperature for Bose-Einstein condensation T_c, we observe

reduced fluctuations down to -4.9dB below the atom shot noise level.

Fluctuations rise to more than +3.8dB close to T_c, before reaching the shot

noise level for higher temperatures. We use two-mode and classical field

simulations to model these results. This allows us to confirm that the

super-shot noise fluctuations directly originate from quantum statistics.

\\ ( http://arxiv.org/abs/1005.1922 , 1781kb)

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arXiv:1005.1963

Date: Tue, 11 May 2010 22:27:07 GMT (318kb)

Title: Two-dimensional expansion of a condensed dense Bose gas

Authors: E.S. Annibale, A. Gammal, K. Ziegler

Categories: cond-mat.quant-gas nlin.PS

Comments: 5 pages, 8 figures

\\

We study the expansion dynamics of a condensate in a strongly interacting

Bose gas in the presence of an obstacle. Our focus is on the generation of

shock waves after the Bose gas has passed the obstacle. The strongly

interacting Bose gas is described in the slave-boson representation. A

saddle-point approximation provides a nonlinear equation of motion for the

macroscopic wave function, analogous to the Gross-Pitaevskii equation of a

weakly interacting Bose gas but with different nonlinearity. We compare the

results with the Gross-Pitaevskii dynamics of a weakly interacting Bose gas and

find a similar behavior with a slower behavior of the strongly interacting

system.

\\ ( http://arxiv.org/abs/1005.1963 , 318kb)

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arXiv:1005.1990

Date: Wed, 12 May 2010 05:12:05 GMT (33kb,D)

Title: Beyond universality in three-body recombination: an Effective Field

Theory treatment

Authors: C. Ji, L. Platter, D. R. Phillips

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

Comments: 14 pages, 4 figures

Report-no: INT-PUB-10-020, HISKP-TH-10-11

\\

We discuss the impact of a finite effective range on three-body systems

interacting through a large two-body scattering length. By employing a

perturbative analysis in an effective field theory well-suited to this scale

hierarchy we find that an additional three-body parameter is required for

consistent renormalization once range corrections are considered. This allows

us to extend previously discussed universal relations between different

observables in the recombination of cold atoms to account for the presence of a

finite effective range. We show that such range corrections improve the

agreement with experimental data for Lithium-7 data obtained by the Bar-Ilan

group. They cannot, however, explain the relationship between positive- and

negative-scattering-length data on Lithium-7 recombination taken by the Rice

group.

\\ ( http://arxiv.org/abs/1005.1990 , 33kb)

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arXiv:1005.2011

Date: Wed, 12 May 2010 07:40:02 GMT (116kb)

Title: Parametric amplification of matter waves in dipolar spinor Bose-Einstein

condensates

Authors: F. Deuretzbacher, G. Gebreyesus, O. Topic, M. Scherer, B. L\"ucke, W.

Ertmer, J. Arlt, C. Klempt, L. Santos

Categories: cond-mat.quant-gas

\\

Spin-changing collisions may lead under proper conditions to the parametric

amplification of matter waves in spinor Bose-Einstein condensates. Magnetic

dipole-dipole interactions, although typically very weak in alkaline atoms, are

shown to play a very relevant role in the amplification process. We show that

these interactions may lead to a strong dependence of the amplification

dynamics on the angle between the trap axis and the magnetic-field orientation.

We analyze as well the important role played by magnetic-field gradients, which

modify also strongly the amplification process. Magnetic-field gradients must

be hence carefully controlled in future experiments, in order to observe

clearly the effects of the dipolar interactions in the amplification dynamics.

\\ ( http://arxiv.org/abs/1005.2011 , 116kb)

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arXiv:1005.2069

Date: Wed, 12 May 2010 12:22:50 GMT (482kb)

Title: The Generation, Evolution and Decay of Pure Quantum Turbulence: A Full

Biot-Savart Simulation

Authors: Shoji Fujiyama, Akira Mitani, Makoto Tsubota, David I. Bradley, Shaun

N. Fisher, Anthony M. Guenault, Richard P. Haley, George R. Pickett and

Viktor Tsepelin

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

Comments: 5 pages, 4 figures, accepted for PRB Rapid Communications (11May2010)

\\

A zero temperature superfluid is arguably the simplest system in which to

study complex fluid dynamics, such as turbulence. We describe computer

simulations of such turbulence and compare the results directly with recent

experiments in superfluid 3He-B. We are able to follow the entire process of

the production, evolution, and decay of quantum turbulence. We find striking

agreement between simulation and experiment and gain new insights into the

mechanisms involved.

\\ ( http://arxiv.org/abs/1005.2069 , 482kb)

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arXiv:1005.2153

Date: Wed, 12 May 2010 16:56:07 GMT (1065kb)

Title: Coherent excitation of a single atom to a Rydberg state

Authors: Y. Miroshnychenko, A. Ga\"etan, C. Evellin, P. Grangier, D. Comparat,

P. Pillet, T. Wilk, and A. Browaeys

Categories: quant-ph

\\

We present the coherent excitation of a single Rubidium atom to the Rydberg

state (58d3/2) using a two-photon transition. The experimental setup is

described in detail, as well as experimental techniques and procedures. The

coherence of the excitation is revealed by observing Rabi oscillations between

ground and Rydberg states of the atom. We analyze the observed oscillations in

detail and compare them to numerical simulations which include imperfections of

our experimental system. Strategies for future improvements on the coherent

manipulation of a single atom in our settings are given.

\\ ( http://arxiv.org/abs/1005.2153 , 1065kb)

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arXiv:1005.2203

Date: Wed, 12 May 2010 20:40:38 GMT (53kb)

Title: BECs on slightly asymmetric double-well potentials

Authors: B. Julia-Diaz, J. Martorell, A. Polls

Categories: cond-mat.quant-gas

Comments: 6 pages, 4 figures, to appear in Phys. Rev. A

\\

An analytical insight into the symmetry breaking mechanisms underlying the

transition from Josephson to self-trapping regimes in Bose-Einstein condensates

is presented. We obtain expressions for the ground state properties of the

system of a gas of attractive bosons modelized by a two site Bose-Hubbard

hamiltonian with an external bias. Simple formulas are found relating the

appearance of fragmentation in the condensate with the large quantum

fluctuations of the population imbalance occurring in the transition from the

Josephson to the self-trapped regime.

\\ ( http://arxiv.org/abs/1005.2203 , 53kb)

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arXiv:1005.2366

Date: Thu, 13 May 2010 16:05:02 GMT (676kb,D)

Title: Competition between pairing and ferromagnetic instabilities in ultracold

Fermi gases near Feshbach resonances

Authors: David Pekker, Mehrtash Babadi, Rajdeep Sensarma, Nikolaj Zinner, Lode

Pollet, Martin W. Zwierlein, Eugene Demler

Categories: cond-mat.quant-gas

Comments: 4+epsilon pages, 4 figures

\\

We study the quench dynamics of a two-component ultracold Fermi gas from the

weak into the strong interaction regime, where the short time dynamics are

governed by the exponential growth rate of unstable collective modes. We obtain

an effective interaction that takes into account both Pauli blocking and the

energy dependence of the scattering amplitude near a Feshbach resonance. Using

this interaction we analyze the competing instabilities towards Stoner

ferromagnetism and pairing.

\\ ( http://arxiv.org/abs/1005.2366 , 676kb)

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arXiv:1005.2389 (*cross-listing*)

Date: Thu, 13 May 2010 18:35:29 GMT (32kb)

Title: Basic zeta functions and some applications in physics

Authors: Klaus Kirsten

Categories: hep-th math-ph math.MP quant-ph

Comments: To appear in "A Window into Zeta and Modular Physics", Mathematical

Sciences Research Institute Publications, Vol. 57, 2010, Cambridge University

Press

\\

It is the aim of these lectures to introduce some basic zeta functions and

their uses in the areas of the Casimir effect and Bose-Einstein condensation. A

brief introduction into these areas is given in the respective sections. We

will consider exclusively spectral zeta functions, that is zeta functions

arising from the eigenvalue spectrum of suitable differential operators. There

is a set of technical tools that are at the very heart of understanding

analytical properties of essentially every spectral zeta function. Those tools

are introduced using the well-studied examples of the Hurwitz, Epstein and

Barnes zeta function. It is explained how these different examples of zeta

functions can all be thought of as being generated by the same mechanism,

namely they all result from eigenvalues of suitable (partial) differential

operators. It is this relation with partial differential operators that

provides the motivation for analyzing the zeta functions considered in these

lectures. Motivations come for example from the questions "Can one hear the

shape of a drum?" and "What does the Casimir effect know about a boundary?".

Finally "What does a Bose gas know about its container?"

\\ ( http://arxiv.org/abs/1005.2389 , 32kb)

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\\

arXiv:1005.2403

Date: Thu, 13 May 2010 19:49:15 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

\\

A novel supersolid phase is predicted for an ensemble of Rydberg atoms in the

dipole-blockade regime, interacting via a repulsive dipolar potential

"softened" at short distances. Using exact numerical techniques, we study the

low temperature phase diagram of this system, and observe an intriguing phase

consisting of a crystal of mesoscopic superfluid droplets. At low temperature,

phase coherence throughout the whole system, and the ensuing bulk

superfluidity, are established through tunnelling of identical particles

between neighbouring droplets.

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

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The replacements:

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\\

arXiv:0901.4385

replaced with revised version Mon, 10 May 2010 11:00:54 GMT (1014kb)

Title: Metastable Quantum Phase Transitions in a Periodic One-dimensional Bose

Gas: Mean-Field and Bogoliubov Analyses

Authors: R. Kanamoto, L. D. Carr, M. Ueda

Categories: cond-mat.other

Journal-ref: Phys. Rev. A 79, 063616 (2009)

DOI: 10.1103/PhysRevA.79.063616

\\ ( http://arxiv.org/abs/0901.4385 , 1014kb)

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\\

arXiv:0903.0968

replaced with revised version Wed, 12 May 2010 09:15:28 GMT (446kb)

Title: Parametrically excited "Scars" in Bose-Einstein condensates

Authors: Nadav Katz and Oded Agam

Categories: cond-mat.other

\\ ( http://arxiv.org/abs/0903.0968 , 446kb)

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\\

arXiv:0910.2805

replaced with revised version Mon, 10 May 2010 11:05:02 GMT (1126kb)

Title: Metastable quantum phase transitions in a periodic one-dimensional Bose

gas: II. Many-body theory

Authors: R. Kanamoto, L.D. Carr, M. Ueda

Categories: cond-mat.quant-gas

Journal-ref: Phys. Rev. A 81, 023625 (2010); Erratum: Phys. Rev. A 81,

049903(E) (2010)

DOI: 10.1103/PhysRevA.81.023625; 10.1103/PhysRevA.81.049903

\\ ( http://arxiv.org/abs/0910.2805 , 1126kb)

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\\

arXiv:0911.3157

replaced with revised version Tue, 11 May 2010 09:37:26 GMT (1051kb)

Title: Spontaneous population imbalance in two-component Bose and Fermi gases

Authors: Shintaro Takayoshi, Masahiro Sato, Shunsuke Furukawa

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

Comments: 7 pages, 5 figures

Journal-ref: Phys. Rev. A 81, 053606 (2010)

DOI: 10.1103/PhysRevA.81.053606

\\ ( http://arxiv.org/abs/0911.3157 , 1051kb)

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\\

arXiv:0912.1239

replaced with revised version Wed, 12 May 2010 14:15:14 GMT (1918kb)

Title: Macroscopic self trapping in BECs: analysis of a dynamical quantum phase

transition

Authors: B. Julia-Diaz, D. Dagnino, M. Lewenstein, J. Martorell, A. Polls

Categories: cond-mat.quant-gas

Comments: Fig 6c,d corrected. 7 pages, 10 eps figures

Journal-ref: Phys. Rev. A 81, 023615 (2010)

DOI: 10.1103/PhysRevA.81.023615

\\ ( http://arxiv.org/abs/0912.1239 , 1918kb)

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\\

arXiv:0912.5022

replaced with revised version Mon, 10 May 2010 13:56:31 GMT (1541kb,D)

Title: Temporal coherence, anomalous moments, and pairing correlations in the

classical-field description of a degenerate Bose gas

Authors: T. M. Wright, P. B. Blakie, and R. J. Ballagh

Categories: cond-mat.quant-gas

Comments: 11 pages, 6 figures. v2: References added. Abstract and introduction

revised

\\ ( http://arxiv.org/abs/0912.5022 , 1541kb)

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\\

arXiv:1001.1004

replaced with revised version Tue, 11 May 2010 19:13:40 GMT (438kb)

Title: RF-field-induced Feshbach resonances

Authors: T. V. Tscherbul, T. Calarco, I. Lesanovsky, R. V. Krems, A. Dalgarno,

J. Schmiedmayer

Categories: physics.atom-ph

Comments: 10 pages, 4 figures; minor typos corrected, journal reference added

Journal-ref: Phys. Rev. A 81, 050701(R) (2010)

DOI: 10.1103/PhysRevA.81.050701

\\ ( http://arxiv.org/abs/1001.1004 , 438kb)

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\\

arXiv:1002.0578

replaced with revised version Fri, 7 May 2010 13:16:18 GMT (272kb)

Title: Generalized Rashba spin-orbit coupling for cold atoms

Authors: Gediminas Juzeliunas, Julius Ruseckas, Jean Dalibard

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

Comments: 8 figures; corrected typos and figures

Journal-ref: Phys. Rev. A 81, 053403 (2010)

DOI: 10.1103/PhysRevA.81.053403

\\ ( http://arxiv.org/abs/1002.0578 , 272kb)

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\\

arXiv:1002.4652

replaced with revised version Thu, 13 May 2010 18:24:29 GMT (175kb)

Title: Fermi liquid theory of ultra-cold trapped Fermi gases: Implications for

Pseudogap Physics and Other Strongly Correlated Phases

Authors: Chih-Chun Chien and K. Levin

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

Comments: 4 pages, 2 figures, revised version

Report-no: LA-UR 10-00975

\\ ( http://arxiv.org/abs/1002.4652 , 175kb)

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\\

arXiv:1004.4134

replaced with revised version Fri, 7 May 2010 20:20:57 GMT (195kb,D)

Title: Oscillating solitons in a three component BEC

Authors: Piotr Szankowski, Eryk Infeld, Marek Trippenbach

Categories: cond-mat.quant-gas

Comments: 4 pages, 4 figures

\\ ( http://arxiv.org/abs/1004.4134 , 195kb)

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\\

arXiv:1004.4499

replaced with revised version Mon, 10 May 2010 13:54:58 GMT (115kb)

Title: Finite temperature QMC study of the one-dimensional polarized Fermi gas

Authors: M. J. Wolak, V. G. Rousseau, C. Miniatura, B. Gremaud, R. T.

Scalettar, and G. G. Batrouni

Categories: cond-mat.quant-gas

Comments: 10 pages, 13 figures We added a discussion of the behaviour of the

FFLO peak as a function of the attractive interaction strength

\\ ( http://arxiv.org/abs/1004.4499 , 115kb)

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\\

arXiv:1005.0461

replaced with revised version Fri, 7 May 2010 15:05:28 GMT (55kb)

Title: Super-Tonks-Girardeau gas of spin-1/2 interacting fermions

Authors: Liming Guan and Shu Chen

Categories: cond-mat.quant-gas

Comments: 4 pages, 4 figures

\\ ( http://arxiv.org/abs/1005.0461 , 55kb)

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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 Thu Jun 10 2010 - 16:22:09 EST

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