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

Date: Fri, 18 Jun 2010 17:16:57 +1000

Date: Fri, 18 Jun 2010 17:16:57 +1000

Dear subscribers,

This week's selection was compiled by Chris Foster, and contains 34 new

abstracts and 13 replacements.

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arXiv:1005.3846 (*cross-listing*)

Date: Thu, 20 May 2010 21:31:52 GMT (489kb)

Title: Cold heteronuclear atom-ion collisions

Authors: Christoph Zipkes, Stefan Palzer, Lothar Ratschbacher, Carlo Sias,

Michael K\"ohl

Categories: physics.atom-ph quant-ph

\\

We study cold heteronuclear atom ion collisions by immersing a trapped single

ion into an ultracold atomic cloud. Using ultracold atoms as reaction targets,

our measurement is sensitive to elastic collisions with extremely small energy

transfer. The observed energy-dependent elastic atom-ion scattering rate

deviates significantly from the prediction of Langevin but is in full agreement

with the quantum mechanical cross section. Additionally, we characterize

inelastic collisions leading to chemical reactions at the single particle level

and measure the energy-dependent reaction rate constants. The reaction products

are identified by in-trap mass spectrometry, revealing the branching ratio

between radiative and non-radiative charge exchange processes.

\\ ( http://arxiv.org/abs/1005.3846 , 489kb)

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arXiv:1005.3936

Date: Fri, 21 May 2010 11:14:23 GMT (84kb)

Title: Josephson effects in one-dimensional supersolids

Authors: M. Kunimi, Y. Nagai and Y. Kato

Categories: cond-mat.quant-gas

Comments: 5 pages, 5 figures

\\

We demonstrate that superfluidity past an obstacle is possible in a solid

phase in the one-dimensional Gross-Pitaevskii equation with a finite-range

two-body interaction. The phenomenon we find is analogous to the DC Josephson

effect in superconductors and we deduce the " Josephson relation " between the

current and phase difference of the condensates separated by the obstacle. The

phase diagram in the plane of the current and the interaction strength is

given.

\\ ( http://arxiv.org/abs/1005.3936 , 84kb)

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arXiv:1005.3964

Date: Fri, 21 May 2010 14:02:15 GMT (1075kb,D)

Title: A slow gravity compensated Atom Laser

Authors: G. Kleine B\"uning, J. Will, W. Ertmer, C. Klempt, J. Arlt

Categories: cond-mat.quant-gas

Comments: 7 pages, 8 figures, to be published in Applied Physics B

DOI: 10.1007/s00340-010-4078-7

\\

We report on a slow guided atom laser beam outcoupled from a Bose-Einstein

condensate of 87Rb atoms in a hybrid trap. The acceleration of the atom laser

beam can be controlled by compensating the gravitational acceleration and we

reach residual accelerations as low as 0.0027 g. The outcoupling mechanism

allows for the production of a constant flux of 4.5x106 atoms per second and

due to transverse guiding we obtain an upper limit for the mean beam width of

4.6 \mu\m. The transverse velocity spread is only 0.2 mm/s and thus an upper

limit for the beam quality parameter is M2=2.5. We demonstrate the potential

of the long interrogation times available with this atom laser beam by

measuring the trap frequency in a single measurement. The small beam width

together with the long evolution and interrogation time makes this atom laser

beam a promising tool for continuous interferometric measurements.

\\ ( http://arxiv.org/abs/1005.3964 , 1075kb)

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arXiv:1005.3997

Date: Fri, 21 May 2010 16:19:49 GMT (1421kb)

Title: Antiferromagnetic Order and Bose-Einstein Condensation in

Strongly-Correlated Cold-Atom Systems: Bosonic t-J Model in the Double-CP1

Representation

Authors: Yuki Nakano, Takumi Ishima, Naohiro Kobayashi, Kazuhiko Sakakibara,

Ikuo Ichinose, Tetsuo Matsui

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

Comments: 13 pages, 17 figures

\\

We study the three-dimensional bosonic t-J model, i.e., the t-J model of

"bosonic electrons" at finite temperatures. This model describes a system of

cold bosonic atoms with two species in an optical lattice. The model is derived

from the Hubbard model for very large on-site repulsive interaction between

bosons of same species (hard-core nature) and also strong correlations between

different species. The operator B_{x\sigma} for an atom at the site x with a

two-component (pseudo-) spin \sigma (=1,2) is treated as a hard-core boson

operator, and represented by a composite of two slave particles; a spinon

described by a CP1 field (Schwinger boson) z_{x\sigma} and a holon described

by a hard-core-boson field \phi_x as B_{x\sigma}=\phi^\dag_x z_{x\sigma}.

\phi_x is then expressed by a pseudo-spin, which is, in turn, represented by

another CP1 (pseudo) spinon w_{x\eta} as \phi_x = w_{x2}^\dag w_{x1}. We then

have a double-CP1 representation of the model by z_{x\sigma} and w_{x\eta}. By

means of Monte Carlo simulations of this bosonic t-J model, we study its phase

structure and the possible phenomena like appearance of antiferromagnetic

long-range order, Bose-Einstein condensation, phase separation, etc. They

should be compared with the possible experimental results of a recently studied

boson-boson mixture like ^87Rb and ^41K in an optical lattice.

\\ ( http://arxiv.org/abs/1005.3997 , 1421kb)

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arXiv:1005.4024

Date: Fri, 21 May 2010 17:40:15 GMT (5403kb)

Title: Black-hole lasers in Bose-Einstein condensates

Authors: Stefano Finazzi and Renaud Parentani

Categories: cond-mat.quant-gas gr-qc

Comments: iopams, 36 pages, 14 figures, 1 table; for associated gif animations,

see http://people.sissa.it/~finazzi/bec_bhlasers/movies/

\\

We consider elongated condensates that cross twice the speed of sound. In the

absence of periodic boundary conditions, the phonon spectrum possesses a

discrete and finite set of complex frequency modes which induce a laser effect.

This effect is due, on one hand, to the anomalous dispersion of the phonons

and, on the other hand, to the supersonic region which acts as a resonant

cavity. We numerically compute the complex frequencies and density-density

correlation function. We obtain patterns with very specific signatures. In

terms of the gravitational analogy, the flows we consider correspond to a pair

of black hole and white hole horizons, and the laser effect can be conceived as

a self-amplified Hawking radiation. This is verified by comparing the outgoing

flux at early time with the standard black hole radiation.

\\ ( http://arxiv.org/abs/1005.4024 , 5403kb)

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arXiv:1005.4027

Date: Fri, 21 May 2010 17:45:21 GMT (660kb)

Title: Bose-Einstein supersolid phase for a novel type of momentum dependent

interaction

Authors: Xiaopeng Li and W. Vincent Liu and Chungwei Lin

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

Comments: 4 pages 3 figures

\\

Motivated by the experiments of dipolar quantum gases, we study a system of

bosons with long range interaction in the regime between superfluid and Wigner

crystal phases. From the effective field theory analysis of low energy

fluctuations and the variational comparison of energies, a novel class of

interaction potentials is found to favor crystalline Bose-Einstein condensation

in the ground state against both the standard homogeneous BEC and

non-superfluid Wigner crystal states. The mechanism is that the potentials

display a minimal value at a finite momentum considerably lower than at zero

momentum.

\\ ( http://arxiv.org/abs/1005.4027 , 660kb)

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arXiv:1005.4076

Date: Fri, 21 May 2010 20:59:29 GMT (216kb)

Title: Observation of a two-dimensional Fermi gas of atoms

Authors: Kirill Martiyanov, Vasiliy Makhalov, Andrey Turlapov

Categories: cond-mat.quant-gas

\\

We have prepared a degenerate gas of fermionic atoms which move in two

dimensions while the motion in the third dimension is "frozen" by tight

confinement and low temperature. {\it In situ} imaging provides direct

measurement of the density profile and temperature. The gas is confined in a

defect-free optical potential, and the interactions are widely tunable by means

of a Fano--Feshbach resonance. This system can be a starting point for

exploration of 2D Fermi physics and critical phenomena in a pure, controllable

environment.

\\ ( http://arxiv.org/abs/1005.4076 , 216kb)

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arXiv:1005.4085 (*cross-listing*)

Date: Fri, 21 May 2010 21:33:20 GMT (193kb,D)

Title: Tunable Cavity Optomechanics with Ultracold Atoms

Authors: T.P. Purdy, D.W.C. Brooks, T. Botter, N. Brahms, Z.-Y. Ma and D.M.

Stamper-Kurn

Categories: quant-ph physics.atom-ph physics.optics

Comments: 4 pages, 5 figures

\\

We present an atom-chip-based realization of quantum cavity optomechanics

with cold atoms localized within a Fabry-Perot cavity. Effective sub-wavelength

positioning of the atomic ensemble allows for tuning the linear and quadratic

optomechanical coupling parameters, varying the sensitivity to the displacement

and strain of a compressible gaseous cantilever. We observe effects of such

tuning on cavity optical nonlinearity and optomechanical frequency shifts,

providing their first characterization in the quadratic-coupling regime.

\\ ( http://arxiv.org/abs/1005.4085 , 193kb)

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arXiv:1005.4121

Date: Sat, 22 May 2010 12:02:33 GMT (308kb)

Title: Spin dynamics and domain formation of a spinor Bose-Einstein condensate

in an optical cavity

Authors: Lu Zhou, Han Pu, Hong Y. Ling, Keye Zhang and Weiping Zhang

Categories: cond-mat.quant-gas

Comments: 8 pages, 5 figures, submitted to Phys. Rev. A

\\

We consider a ferromagnetic spin-1 Bose-Einstein condensate (BEC)

dispersively coupled to a unidirectional ring cavity. We show that the ability

of a cavity to modify, in a highly nonlinear fashion, matter-wave phase shifts

adds a new dimension to the study of spinor condensates both within and beyond

the single-mode approximation. In addition to demonstrating strong matter-wave

bistability as in our earlier publication [L. Zhou et al., Phys. Rev. Lett.

103, 160403 (2009)], we show that the interplay between atomic and cavity

fields can greatly enrich both the physics of critical slowing down in spin

mixing dynamics and the physics of spin-domain formation in spinor condensates.

\\ ( http://arxiv.org/abs/1005.4121 , 308kb)

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arXiv:1005.4213 (*cross-listing*)

Date: Sun, 23 May 2010 17:25:03 GMT (320kb)

Title: Cold matter trapping via rotating helical optical potential

Authors: A.Yu.Okulov

Categories: physics.atom-ph cond-mat.quant-gas nlin.PS physics.optics

Comments: 6 pages, 3 figures

\\

We consider a cold bosonic ensemble trapping by a helical interference

pattern in the optical $loop$ scheme. The counter propagating Laguerre-Gaussian

beams with slightly detuned frequencies produce helical potential provided

their optical angular momenta are counter directed. The small frequency

difference required for helix rotation might be induced by Sagnac effect. For

the large number of atoms trapped by a slowly rotating helical optical

potential the Gross-Pitaevskii equation is solved in Thomas-Fermi

approximation. Two possible configurations of the atomic ensemble wavefunction

are presented. The optical $loop$ scheme requirements are briefly formulated.

\\ ( http://arxiv.org/abs/1005.4213 , 320kb)

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arXiv:1005.4377

Date: Mon, 24 May 2010 17:01:33 GMT (109kb,D)

Title: Effect of buffer gas on electromagnetically induced transparency in a

ladder system using thermal rubidium vapor

Authors: Armen Sargsyan, David Sarkisyan, Ulrich Krohn, James Keaveney, Charles

Adams

Categories: physics.atom-ph

Comments: 4 pages, 4 figures

\\

We report on the first observation of electromagnetically induced

transparency (EIT) in a ladder system in the presence of a buffer gas. In

particular we study the 5S1/2 - 5P3/2 - 5D5/2 transition in thermal rubidium

vapor with a neon buffer gas at a pressure of 6 Torr. In contrast to the line

narrowing effect of buffer gas on {\Lambda}-systems we show that the presence

of the buffer gas leads to an additional broadening of (32 ± 5) MHz, which

suggests a cross section for Rb(5D5/2)-Ne of {\sigma} = (7 ± 1) x 10-19 m2.

However, in the limit where the coupling Rabi frequency is larger than k the

collisional dephasing a strong transparency feature can still be observed.

\\ ( http://arxiv.org/abs/1005.4377 , 109kb)

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arXiv:1005.4391 (*cross-listing*)

Date: Mon, 24 May 2010 18:23:06 GMT (501kb)

Title: Cold atoms in rotating optical lattice with nearest neighbour

interaction

Authors: Rashi Sachdeva, Sonika Johri and Sankalpa Ghosh

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

Comments: 9 pages, 3 figures

\\

Extended Bose Hubbard models with nearest neighbour interaction describe

minimally the effect of long range interaction on ultra cold atoms in deep

optical lattices. Rotation of such optical lattices subject such neutral cold

atoms to the effect of an artificial magnetic field. The modification of the

phase boundaries of the Density wave and Mott Insulator phases due to this

rotation are shown to be related to the edge spectrum of spinorial and scalar

Harper equation. Corresponding profiles of the checkerboard vortex states with

sublattice modulated superfluid order parameter near density wave phase

boundary are calculated.

\\ ( http://arxiv.org/abs/1005.4391 , 501kb)

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arXiv:1005.4476

Date: Tue, 25 May 2010 03:56:07 GMT (581kb)

Title: Ultracold bosons in a synthetic periodic magnetic field: Mott phases and

re-entrant superfluid-insulator transitions

Authors: K. Saha, K. Sengupta, and K. Ray

Categories: cond-mat.str-el

Comments: 8 pages, 11 figures, v1

\\

We study Mott phases and superfluid-insulator (SI) transitions of ultracold

bosonic atoms in a two-dimensional square optical lattice at commensurate

filling and in the presence of a synthetic periodic vector potential

characterized by a strength $p$ and a period $l=qa$, where $q$ is an integer

and $a$ is the lattice spacing. We show that the Schr\"odinger equation for the

non-interacting bosons in the presence of such a periodic vector potential can

be reduced to an one-dimensional Harper-like equation which yields $q$ energy

bands. The lowest of these bands have either single or double minima whose

position within the magnetic Brillouin zone can be tuned by varying $p$ for a

given $q$. Using these energies and a strong-coupling expansion technique, we

compute the phase diagram of these bosons in the presence of a deep optical

lattice. We chart out the $p$ and $q$ dependence of the momentum distribution

of the bosons in the Mott phases near the SI transitions and demonstrate that

the bosons exhibit several re-entrant field-induced SI transitions for any

fixed period $q$. We also predict that the superfluid density of the resultant

superfluid state near such a SI transition has a periodicity $q$ ($q/2$) in

real space for odd (even) $q$ and suggest experiments to test our theory.

\\ ( http://arxiv.org/abs/1005.4476 , 581kb)

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arXiv:1005.4519

Date: Tue, 25 May 2010 09:37:30 GMT (339kb)

Title: Extracting the Mott gap from energy measurements in trapped atomic gases

Authors: Juan Carrasquilla and Federico Becca

Categories: cond-mat.quant-gas

Comments: 4 pages and 5 figures

\\

We show that the measure of the so-called {\it release-energy}, which is an

experimentally accessible quantity, makes it possible to assess the value of

the Mott gap in the presence of the confinement potential that is unavoidable

in the actual experimental setup. Indeed, the curve of the release-energy as a

function of the total number of particles shows kinks that are directly related

to the existence of excitation gaps. Calculations are presented within the

Gutzwiller approach, but the final results go beyond this simple approximation

and represent a genuine feature of the real system. In the case of harmonic

confinement, the Mott gaps may be renormalized with respect to the uniform

case. On the other hand, in the case of the recently proposed off-diagonal

confinement, our results show an almost perfect agreement with the homogeneous

case.

\\ ( http://arxiv.org/abs/1005.4519 , 339kb)

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arXiv:1005.4726

Date: Wed, 26 May 2010 03:06:34 GMT (249kb)

Title: Anderson localization of a Tonks-Girardeau gas in potentials with

controlled disorder

Authors: J. Radi\'c, V. Ba\v{c}i\'c, D. Juki\'c, M. Segev, H. Buljan

Categories: cond-mat.quant-gas

\\

We theoretically demonstrate features of Anderson localization in the

Tonks-Girardeau gas confined in one-dimensional (1D) potentials with controlled

disorder. That is, we investigate the evolution of the single particle density

and correlations of a Tonks-Girardeau wave packet in such disordered

potentials. The wave packet is initially trapped, the trap is suddenly turned

off, and after some time the system evolves into a localized steady state due

to Anderson localization. The density tails of the steady state decay

exponentially, while the coherence in these tails increases. The latter

phenomenon corresponds to the same effect found in incoherent optical solitons.

\\ ( http://arxiv.org/abs/1005.4726 , 249kb)

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arXiv:1005.4737

Date: Wed, 26 May 2010 06:21:34 GMT (104kb)

Title: Infinite invariant densities for anomalous diffusion in optical lattices

and other logarithmic potentials

Authors: David A. Kessler and Eli Barkai

Categories: cond-mat.stat-mech math-ph math.MP

Comments: 4 pages, 2 figures

\\

We solve the Fokker-Planck equation for Brownian motion in a logarithmic

potential. When the diffusion constant is below a critical value the solution

approaches a non-normalizable scaling state, reminiscent of an infinite

invariant density. With this non-normalizable density we obtain the phase

diagram of anomalous diffusion for this important process. We briefly discuss

the consequence for a range of physical systems including atoms in optical

lattices and charges in vicinity of long polyelectrolytes. Our work explains in

what sense the infinite invariant density and not Boltzmann's equilibrium

describes the long time limit of these systems.

\\ ( http://arxiv.org/abs/1005.4737 , 104kb)

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arXiv:1005.4738

Date: Wed, 26 May 2010 06:26:21 GMT (1074kb)

Title: Splitting and oscillation of Majorana zero modes in the p-wave BCS-BEC

evolution with plural vortices

Authors: T. Mizushima, K. Machida

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

Comments: 15 pages, 10 figures

\\

We investigate how the vortex-vortex separation changes Majorana zero modes

in the vicinity of the BCS-BEC (Bose-Einstein condensation) topological phase

transition of p-wave resonant Fermi gases. By analytically and numerically

solving the Bogoliubov-de Gennes equation for spinless p-wave superfluids with

plural vortices, it is demonstrated that the quasiparticle tunneling between

neighboring vortices gives rise to the quantum oscillation of the low-lying

spectra on the scale of the Fermi wavelength in addition to the exponential

splitting. This rapid oscillation, which appears in the weak coupling regime as

a consequence of quantum oscillations of quasiparticle wave functions,

disappears in the vicinity of the BCS-BEC topological phase transition. This is

understandable from that the wave function of the Majorana zero modes is

described by the modified Bessel function in the strong coupling regime and

thus it becomes spread over the vortex core region. Due to the exponential

divergence of the modified Bessel function, the concrete realization of the

Majorana zero modes near the topological phase transition requires the

neighboring vortices to be separated beyond the length scale defined by the

coherence length and the dimensionless coupling constant. All these behaviors

are also confirmed by carrying out the full numerical diagonalization of the

non-local Bogoliubov-de Gennes equation in a two dimensional geometry.

Furthermore, this argument is expanded into the case of three-vortex systems,

where a pair of core-bound and edge-bound Majorana states survive at zero

energy state regardless of the vortex separation.

\\ ( http://arxiv.org/abs/1005.4738 , 1074kb)

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arXiv:1005.4760

Date: Wed, 26 May 2010 08:51:50 GMT (249kb)

Title: Texture control in a pseudospin Bose-Einstein condensate

Authors: Gary Ruben, Michael J. Morgan, and David M. Paganin

Categories: cond-mat.quant-gas

Comments: 4 pages, 5 figures, REVTeX4-1

\\

We describe a wavefunction engineering approach to the formation of textures

in a two-component nonrotated Bose-Einstein condensate. By controlling the

phases of wavepackets that combine in a three-wave interference process, a

ballistically-expanding regular lattice-texture is generated, in which the

phases determine the component textures. A particular example is presented of a

lattice-texture composed of half-quantum vortices and spin-2 textures. We

demonstrate the lattice formation with numerical simulations of a viable

experiment, identifying the textures and relating their locations to a linear

theory of wavepacket interference.

\\ ( http://arxiv.org/abs/1005.4760 , 249kb)

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arXiv:1005.4784

Date: Wed, 26 May 2010 10:45:00 GMT (1982kb,D)

Title: Zero-temperature phase diagram of Bose-Fermi gaseous mixtures in optical

lattices

Authors: T. P. Polak and T. K. Kope\'c

Categories: cond-mat.quant-gas

DOI: 10.1103/PhysRevA.81.043612

\\

We study the ground state phase diagram of a mixture of bosonic and fermionic

cold atoms confined on two- and three-dimensional optical lattices. The

coupling between bosonic fluctuations and fermionic atoms can be attractive or

repulsive and has similarities with electron-phonon coupling in crystals. We

investigate behavior of the mixtures in the limit, where the Bogoliubov sound

velocity that dictates bosonic dynamics is comparable to the Fermi velocity,

hence the retardation effects are important part of the physics. The dynamic

Lindhard response function of the fermionic density to changes in the bosonic

number of particles above some critical frequency can alter the sign and in

consequence the inter-species interaction between particles becomes repulsive

in contrast to the static limit (instantaneous and always attractive).

Considering the above we show that the structure of the phase diagrams

crucially depends on the difference in masses of the bosons and fermions. We

discuss the situations where integrating out fermionic field provides an

additional interaction that can decrease or increase bosonic coherence.

\\ ( http://arxiv.org/abs/1005.4784 , 1982kb)

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arXiv:1005.4787

Date: Wed, 26 May 2010 10:56:10 GMT (879kb,D)

Title: Frustration effects in rapidly rotating square and triangular optical

lattices

Authors: T. P. Polak and T. K. Kope\'c

Categories: cond-mat.quant-gas

DOI: 10.1103/PhysRevA.79.063629

\\

We discuss the ground state of the two-dimensional Bose-Hubbard (BH)

Hamiltonian, relevant for rotating gaseous Bose-Einstein condensates, by

employing \mathrm{U}\left(1\right) quantum rotor approach and the topologically

constrained path integral that includes a summation over

\mathrm{U}\left(1\right) topological charge. We derive an effective quantum

action for the BH model, which enables a non-perturbative treatment of the

zero-temperature phase transition. We calculate the ground-state phase diagram,

analytically deriving maximum repulsive energy for several rational values of

the frustration rotation parameter f=0, 1/2, 1/3, 1/4, and 1/6 for the square

and triangular lattice, which improves upon previous theoretical treatments.

The ground state of the rotating Bose-Einstein condensates on a triangular

lattice appears to be most stable against the effects of rotation. Performed

calculations revealed strong dependence of the critical ratio of the kinetic

energy to the repulsive on-site energy, that separates the global coherent from

the insulating state, on topology of the lattice.

\\ ( http://arxiv.org/abs/1005.4787 , 879kb)

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arXiv:1005.4790 (*cross-listing*)

Date: Wed, 26 May 2010 11:18:20 GMT (73kb)

Title: Reduction of quantum noise and increase of amplification of

gravitational waves signals in Michelson interferometer by the use of

squeezed states

Authors: Yacob Ben-Aryeh

Categories: gr-qc quant-ph

Comments: 6 pages

Report-no: 7664

\\

It is shown in the present Letter that the quantum noise due to high laser

intensities in Michelson interferometer for gravitational waves detection can

be reduced by sending squeezed vacuum states to the 'dark' port of the

interferometer. The experimental details of such physical system have been

described in a recent article by Barak and Ben-Aryeh (JOSA-B, 25, 361(2008)).

In another very recent article by Voronov and Weyrauch (Phys. Rev.A 81, 053816

(2010)) they have followed our methods for treating the same physical system,

and have pointed out an error in the sign of one of our expressions thus

claiming for the elimination of our physical results. I show here a method by

which the expectation value for the photon number operator is increased and at

the same time the standard deviation is reduced. Although due to the mistake in

sign in our expression the physical method for obtaining such result is

different from our original study [1], the main physical effect can remain .

\\ ( http://arxiv.org/abs/1005.4790 , 73kb)

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arXiv:1005.4816

Date: Wed, 26 May 2010 13:56:13 GMT (1195kb,D)

Title: Ultracold Atoms in an Optical Lattice with Dynamically Variable

Periodicity

Authors: S. Al-Assam, R. A. Williams, C. J. Foot

Categories: cond-mat.quant-gas

Comments: 4 pages, 3 figures

\\

The first use of a dynamic `accordion' lattice with ultracold atoms is

demonstrated. Ultracold atoms of $^{87}$Rb are trapped in a two-dimensional

optical lattice, and the spacing of the lattice is then increased in both

directions from 2.2 microns to 5.5 microns. It is shown that the atoms remain

bound for expansion times as short as a few milliseconds, and the

experimentally measured minimum ramp time is found to agree well with numerical

calculations. This technique allows an experiment such as quantum simulations

to be performed with a lattice spacing smaller than the resolution limit of the

imaging system, while allowing imaging of the atoms at individual lattice sites

by subsequent expansion of the optical lattice.

\\ ( http://arxiv.org/abs/1005.4816 , 1195kb)

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arXiv:1005.4865

Date: Wed, 26 May 2010 16:17:36 GMT (581kb)

Title: A master equation approach for interacting slow- and stationary-light

polaritons

Authors: Martin Kiffner and Michael J. Hartmann

Categories: quant-ph

\\

A master equation approach for the description of dark-state polaritons in

coherently driven atomic media is presented. This technique provides a

description of light-matter interactions under conditions of

electromagnetically induced transparency (EIT) that is well suited for the

treatment of polariton losses. The master equation approach allows us to

describe general polariton-polariton interactions that may be conservative,

dissipative or a mixture of both. In particular, it enables us to study

dissipation-induced correlations as a means for the creation of strongly

correlated polariton systems. Our technique reveals a loss mechanism for

stationary-light polaritons that has not been discussed so far. We find that

polariton losses in level configurations with non-degenerate ground states can

be a multiple of those in level schemes with degenerate ground states.

\\ ( http://arxiv.org/abs/1005.4865 , 581kb)

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arXiv:1005.5033

Date: Thu, 27 May 2010 11:38:42 GMT (195kb)

Title: Weak chaos in the disordered nonlinear Schroedinger chain: destruction

of Anderson localization by Arnold diffusion

Authors: D. M. Basko

Categories: cond-mat.dis-nn

Comments: 98 pages

\\

The subject of this study is the long-time equilibration dynamics of a

strongly disordered one-dimensional chain of coupled weakly anharmonic

classical oscillators. It is argued that chaos in this system has a very

particular spatial structure: it can be viewed as a dilute gas of chaotic

spots. Each chaotic spot corresponds to a stochastic pump which drives the

Arnold diffusion of the oscillators surrounding it, thus leading to their

relaxation and thermalization. The most important mechanism of relaxation at

long distances is provided by random migration of the chaotic spots along the

chain, which bears analogy with variable-range hopping of electrons in strongly

disordered solids.

\\ ( http://arxiv.org/abs/1005.5033 , 195kb)

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arXiv:1005.5038

Date: Thu, 27 May 2010 11:46:23 GMT (597kb)

Title: Heisenberg-limited interferometry with pair coherent states and parity

measurements

Authors: Christopher C. Gerry and Jihane Mimih

Categories: quant-ph

\\

After reviewing parity measurement based interferometry with twin-Fock

states, which allows for super-sensitivity (Heisenberg-limited) and

super-resolution, we consider interferometry with two different superpositions

of twin-Fock states, namely two-mode squeezed vacuum states and pair coherent

states. This study is motivated by the experimental challenge of producing

twin-Fock states on opposite sides of a beam splitter. We find that input

two-mode squeezed states, while allowing for Heisenberg-limited sensitivity, do

not yield super-resolutions, whereas we that find both are possible with input

pair coherent states.

\\ ( http://arxiv.org/abs/1005.5038 , 597kb)

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arXiv:1005.5139 (*cross-listing*)

Date: Thu, 27 May 2010 18:03:05 GMT (283kb,X)

Title: A Better Definition of the Kilogram

Authors: Ronald F. Fox, Theodore P. Hill, and Jack Miller

Categories: physics.data-an physics.pop-ph

Comments: 10 pages, no figures

\\

This article reviews several recent proposed redefinitions of the kilogram,

and compares them with respect to practical realizations, uncertainties

(estimated standard deviations), and educational aspects.

\\ ( http://arxiv.org/abs/1005.5139 , 283kb)

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arXiv:1005.5174 (*cross-listing*)

Date: Thu, 27 May 2010 20:42:54 GMT (588kb)

Title: Spin transport in coupled spinor Bose gases

Authors: J.M. McGuirk

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

\\

We report direct measurements of spin transport in a trapped, partially

condensed spinor Bose gas. Detailed analyses of spin flux in this

out-of-equilibrium quantum gas are performed by monitoring the flow of atoms in

different hyperfine spin states. The main mechanisms for motion in this system

are exchange scattering and potential energy inhomogeneity, which lead to spin

waves in the normal component and domain formation in the condensate. We find a

large discrepancy in domain formation timescales with those predicted by

potential-driven formation, indicating strong coupling of the condensate to the

normal component spin wave.

\\ ( http://arxiv.org/abs/1005.5174 , 588kb)

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\\

arXiv:1005.5212

Date: Fri, 28 May 2010 04:31:42 GMT (1228kb)

Title: Heating and Cooling in Adiabatic Mixing process

Authors: Jing Zhou, Zi Cai, Xu-Bo Zou, and Guang-Can Guo

Categories: cond-mat.quant-gas

Comments: 5 pages, 5 figures

\\

We study the effect of interaction on the temperature change in the process

of adiabatic mixing a two-component fermi gases by the real-space Bogoliubov-de

Gennes (BdG) method. We find that in the process of adiabatic mixing, the

competition of the adiabatic expansion and the attractive interaction make it

possible to cool or heal the system depending on strength interactions. The

change of temperature in a bulk system and a trapped system have been

investigated respectively.

\\ ( http://arxiv.org/abs/1005.5212 , 1228kb)

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\\

arXiv:1005.5227

Date: Fri, 28 May 2010 07:08:09 GMT (504kb)

Title: Twenty Hirsch index variants and other indicators giving more or less

preference to highly cited papers

Authors: Michael Schreiber

Categories: physics.soc-ph cs.DL

Comments: 19 pages, including 6 tables and 3 figures accepted for publication

in Annalen der Physik Berlin

\\

The Hirsch index or h-index is widely used to quantify the impact of an

individual's scientific research output, determining the highest number h of a

scientist's papers that received at least h citations. Several variants of the

index have been proposed in order to give more or less preference to highly

cited papers. I analyse the citation records of 26 physicists discussing

various suggestions, in particular A, e, f, g, h(2), h_w, h_T, \hbar, m, {\pi},

R, s, t, w, and maxprod. The total number of all and of all cited publications

as well as the highest and the average number of citations are also compared.

Advantages and disadvantages of these indices and indicators are discussed.

Correlation coefficients are determined quantifying which indices and

indicators yield similar and which yield more deviating rankings of the 26

datasets. For 6 datasets the determination of the indices and indicators is

visualized.

\\ ( http://arxiv.org/abs/1005.5227 , 504kb)

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\\

arXiv:1005.5272

Date: Fri, 28 May 2010 12:01:12 GMT (2787kb)

Title: Weakly linked binary mixtures of F=1 87-Rb Bose-Einstein condensates

Authors: M. Mele-Messeguer, B. Julia-Diaz, M. Guilleumas, A. Polls and A.

Sanpera

Categories: cond-mat.quant-gas

Comments: 44 pages, 19 figures

\\

We present a study of binary mixtures of Bose-Einstein condensates confined

in a double-well potential within the framework of the mean field

Gross-Pitaevskii equation. We reexamine both the single component and the

binary mixture cases for such a potential, and we investigate in which

situations a simpler two-mode approach leads to an accurate description of

their dynamics. We also estimate the validity of the most usual dimensionality

reductions used to solve the Gross-Pitaevskii equations. To this end, we

compare both the semi-analytical two-mode approaches and the numerical

simulations of the 1D reductions with the full 3D numerical solutions of the

Gross-Pitaevskii equation. Our analysis provides a guide to clarify the

validity of several simplified models that describe mean field non-linear

dynamics, using an experimentally feasible binary mixture of an F=1 spinor

condensate with two of its Zeeman manifolds populated, m=+1 and m=-1.

\\ ( http://arxiv.org/abs/1005.5272 , 2787kb)

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\\

arXiv:1005.5282

Date: Fri, 28 May 2010 12:50:10 GMT (27kb)

Title: Electromagnetic and phonon modes for superfluid He-4 with a disk

resonator

Authors: V.M. Loktev and M.D. Tomchenko

Categories: cond-mat.other

Comments: 9 pages, 1 figure

\\

We find the distribution of the electromagnetic field inside and outside a

dielectric disk resonator placed in He-II. It is shown that this field consists

of a collection of "circular" (c-) photons. The wave function \Psi_c of a

c-phonon for the He-II + disk system is calculated in the zero-order

approximation in interaction. Due to the symmetry of the problem, the structure

of \Psi_c is such that a c-phonon possesses, similarly to a c-photon of the

resonator, a definite energy and an angular momentum with respect to the disk

axis, but it does not possess a definite momentum in the disk plane.

\\ ( http://arxiv.org/abs/1005.5282 , 27kb)

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\\

arXiv:1005.5284

Date: Fri, 28 May 2010 12:51:23 GMT (688kb,D)

Title: Generalized Hartree-Fock Theory for Interacting Fermions in Lattices:

Numerical Methods

Authors: Christina V. Kraus and J. Ignacio Cirac

Categories: quant-ph

Comments: 16 pages, 22 figures

\\

We present numerical methods to solve the Generalized Hartree-Fock theory for

fermionic systems in lattices, both in thermal equilibrium and out of

equilibrium. Specifically, we show how to determine the covariance matrix

corresponding to the Fermionic Gaussian state that optimally approximates the

quantum state of the fermions. The methods apply to relatively large systems,

since their complexity only scales quadratically with the number of lattice

sites. Moreover, they are specially suited to describe inhomogenous systems, as

those typically found in recent experiments with atoms in optical lattices, at

least in the weak interaction regime. As a benchmark, we have applied them to

the two-dimensional Hubbard model on a 10x10 lattice with and without an

external confinement.

\\ ( http://arxiv.org/abs/1005.5284 , 688kb)

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\\

arXiv:1005.5306 (*cross-listing*)

Date: Fri, 28 May 2010 14:50:01 GMT (435kb)

Title: Feshbach resonances of harmonically trapped atoms

Authors: Philipp-Immanuel Schneider, Yulian V. Vanne, and Alejandro Saenz

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

Comments: 4 pages, 3 figures

\\

Employing a short-range two-channel description we derive an analytic

equation for the eigenenergies and contribution of the resonant bound state

(RBS) of atoms in harmonic traps at a Feshbach resonance. On this basis we

obtain a new parameterization of the energy-dependent scattering length which

differs significantly from the one previously employed. We validate the model

by comparison with experiments and full numerical calculations for 6Li-87Rb.

Finally, we explore a new resonance phenomenon arising in traps -- a splitting

between the resonance and the maximal RBS admixture -- which is demonstrated to

have important impact on atom-loss processes.

\\ ( http://arxiv.org/abs/1005.5306 , 435kb)

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\\

arXiv:1005.5328

Date: Fri, 28 May 2010 16:21:10 GMT (6kb)

Title: Proof of the Standard Quantum Limit for Monitoring Free-Mass Position

Authors: Seiji Kosugi

Categories: quant-ph

Comments: 4 pages, no figure

\\

The measurement result of the moved distance for a free mass m during the

time t between two position measurements cannot be predicted with uncertainty

smaller than sqrt{hbar t/2m}. This is formulated as a standard quantum limit

(SQL) and it has been proven to always hold for the following position

measurement: a probe is set in a prescribed position before the measurement.

Just after the interaction of the mass with the probe, the probe position is

measured, and using this value, the measurement results of the pre-measurement

and post-measurement positions are estimated.

\\ ( http://arxiv.org/abs/1005.5328 , 6kb)

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The replacements:

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\\

arXiv:0912.4011

replaced with revised version Sun, 23 May 2010 14:01:39 GMT (1390kb)

Title: Modulation of breathers in cigar-shaped Bose-Einstein condensates

Authors: W. B. Cardoso, A. T. Avelar, D. Bazeia

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

Journal-ref: Physics Letters A,374(2010)2640-2645

DOI: 10.1016/j.physleta.2010.04.050

\\ ( http://arxiv.org/abs/0912.4011 , 1390kb)

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\\

arXiv:1005.1309 (*cross-listing*)

replaced with revised version Mon, 24 May 2010 21:06:29 GMT (1416kb)

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

Comments: minor edit: fixed technical problem with arxiv's processing of .eps

figure

\\ ( http://arxiv.org/abs/1005.1309 , 1416kb)

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\\

arXiv:1001.4371

replaced with revised version Tue, 25 May 2010 12:33:43 GMT (58kb,D)

Title: Three-body problem in heteronuclear mixtures with resonant interspecies

interaction

Authors: K. Helfrich, H.-W. Hammer, D.S. Petrov

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

Comments: 13 pages, 8 figures, minor changes, published version

Report-no: HISKP-TH-09/36

Journal-ref: Phys.Rev.A81:042715,2010

DOI: 10.1103/PhysRevA.81.042715

\\ ( http://arxiv.org/abs/1001.4371 , 58kb)

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\\

arXiv:0912.1633

replaced with revised version Tue, 25 May 2010 17:31:01 GMT (50kb)

Title: Wave functions of the super Tonks-Girardeau gas and the trapped 1D hard

sphere Bose gas

Authors: M.D. Girardeau, G.E. Astrakharchik

Categories: cond-mat.quant-gas

Comments: 4 pages, 1 figure, revtex4. Final version accepted by Phys. Rev. A

Rapid Communications

\\ ( http://arxiv.org/abs/0912.1633 , 50kb)

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\\

arXiv:1002.1433

replaced with revised version Wed, 26 May 2010 00:43:42 GMT (485kb)

Title: Ground states and dynamics of population-imbalanced Fermi condensates in

one dimension

Authors: Masaki Tezuka and Masahito Ueda

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

Comments: 20 pages, 15 figures, accepted for publication in New Journal of

Physics

\\ ( http://arxiv.org/abs/1002.1433 , 485kb)

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\\

arXiv:1001.5325

replaced with revised version Wed, 26 May 2010 06:33:44 GMT (696kb)

Title: Vortex structures and zero energy states in the BCS-to-BEC evolution of

p-wave resonant Fermi gases

Authors: T. Mizushima, K. Machida

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

Comments: 15 pages, 9 figures, published version

Journal-ref: Phys. Rev. A 81, 053605 (2010)

\\ ( http://arxiv.org/abs/1001.5325 , 696kb)

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\\

arXiv:0908.3012

replaced with revised version Wed, 26 May 2010 18:59:52 GMT (2277kb)

Title: Classical phases and quantum angles in the description of interfering

Bose-Einstein condensates

Authors: W. J. Mullin and F. Lalo\"e

Categories: quant-ph

Comments: 35 pages, 22 figures

\\ ( http://arxiv.org/abs/0908.3012 , 2277kb)

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\\

arXiv:0910.0603

replaced with revised version Thu, 27 May 2010 05:28:23 GMT (109kb)

Title: The stability of the low-dimensional mixtures of dilute quantum gases

Authors: Yu-Li Lee and Yu-Wen Lee

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

Comments: 8 pages, several paragraphs have been completely rewritten, two

figures and one reference are added

\\ ( http://arxiv.org/abs/0910.0603 , 109kb)

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\\

arXiv:0911.4564 (*cross-listing*)

replaced with revised version Thu, 27 May 2010 11:46:21 GMT (595kb)

Title: Spontaneous Four-Wave Mixing of de Broglie Waves: Beyond Optics

Authors: Valentina Krachmalnicoff (LCFIO), Jean-Christophe Jaskula (LCFIO),

Marie Bonneau (LCFIO), Vanessa Leung (LCFIO), Guthrie B. Partridge (LCFIO),

Denis Boiron (LCFIO), Christoph I Westbrook (LCFIO), Piotr Deuar, Pawel Zin,

Marek Trippenbach, Karen Kheruntsyan

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

Comments:

\\ ( http://arxiv.org/abs/0911.4564 , 595kb)

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\\

arXiv:1002.0195

replaced with revised version Thu, 27 May 2010 13:25:42 GMT (132kb,D)

Title: First and second sound in cylindrically trapped gases

Authors: G. Bertaina, L. Pitaevskii, S. Stringari

Categories: cond-mat.quant-gas

Comments: 4 pages, 2 figures. Paper reformatted, more emphasis on role of

viscosity and thermal conductivity in the long wave length limit, new damping

effect of non dissipative nature identified in second sound above Tc. New

figures presented

\\ ( http://arxiv.org/abs/1002.0195 , 132kb)

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\\

arXiv:1005.2403

replaced with revised version Thu, 27 May 2010 20:41:18 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:0912.2402

replaced with revised version Fri, 28 May 2010 04:36:21 GMT (1164kb)

Title: Continuous-variables entanglement purification with atomic systems

Authors: Stojan Rebic, Stefano Mancini, Giovanna Morigi and David Vitali

Categories: quant-ph

Comments: Published in Feature Issue "Quantum Optical Information Technologies"

Journal-ref: J. Opt. Soc. Am. B 27, A198 (2010)

\\ ( http://arxiv.org/abs/0912.2402 , 1164kb)

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\\

arXiv:1003.5925

replaced with revised version Fri, 28 May 2010 14:39:47 GMT (487kb)

Title: Spin self-rephasing and very long coherence times in a trapped atomic

ensemble

Authors: Christian Deutsch, Fernando Ramirez-Martinez, Clement Lacro\^ute,

Friedemann Reinhard, Tobias Schneider, Jean-No\"el Fuchs, Fr\'ed\'eric

Pi\'echon, Franck Lalo\"e, Jakob Reichel and Peter Rosenbusch

Categories: quant-ph physics.atom-ph

Comments: Revised version; improved description of the theoretical treatment

\\ ( http://arxiv.org/abs/1003.5925 , 487kb)

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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 - 09:32:19 EST

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