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

Date: Fri, 27 Jun 2008 09:40:52 +1000

Date: Fri, 27 Jun 2008 09:40:52 +1000

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

Now only two weeks behind... this week there were 28 new preprints and 12

replacements.

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arXiv:0806.1114

Date: Fri, 6 Jun 2008 09:33:18 GMT (51kb)

Title: Finite size Berezinski-Kosterlitz-Thouless transition at grain

boundaries in solid $^4$He and role of $^3$He impurities

Authors: S. Gaudio, E. Cappelluti, G. Rastelli, L. Pietronero

Categories: cond-mat.other

\\

We analyze the complex phenomenology of the Non-Classical Rotational Inertia

(NCRI) observed at low temperature in solid $^4$He within the context of a two

dimensional Berezinski-Kosterlitz-Thouless transition in a premelted $^4$He

film at the grain boundaries. We show that both the temperature and $^3$He

doping dependence of the NCRI fraction (NCRIF) can be ascribed to finite size

effects induced by the finite grain size. We give an estimate of the average

size of the grains which we argue to be limited by the isotopic $^3$He

impurities and we provide a simple power-law relation between the NCRIF and the

$^3$He concentration.

\\ ( http://arxiv.org/abs/0806.1114 , 51kb)

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arXiv:0806.1181

Date: Fri, 6 Jun 2008 15:00:36 GMT (24kb)

Title: Some remarks on the coherent-state variational approach to nonlinear

boson models

Authors: P. Buonsante and V. Penna (Politecnico di Torino)

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

Comments: 16 pages

Journal-ref: J. Phys. A: Math. Theor., 41 (2008) 175301

DOI: 10.1088/1751-8113/41/17/175301

\\

The mean-field pictures based on the standard time-dependent variational

approach have widely been used in the study of nonlinear many-boson systems

such as the Bose-Hubbard model. The mean-field schemes relevant to

Gutzwiller-like trial states $|F>$, number-preserving states $|\xi >$ and

Glauber-like trial states $|Z>$ are compared to evidence the specific

properties of such schemes. After deriving the Hamiltonian picture relevant to

$|Z>$ from that based on $|F>$, the latter is shown to exhibit a Poisson

algebra equipped with a Weyl-Heisenberg subalgebra which preludes to the

$|Z>$-based picture. Then states $|Z>$ are shown to be a superposition of $\cal

N$-boson states $|\xi>$ and the similarities/differences of the $|Z>$-based and

$|\xi>$-based pictures are discussed. Finally, after proving that the simple,

symmetric state $|\xi>$ indeed corresponds to a SU(M) coherent state, a dual

version of states $|Z>$ and $|\xi>$ in terms of momentum-mode operators is

discussed together with some applications.

\\ ( http://arxiv.org/abs/0806.1181 , 24kb)

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arXiv:0806.1201

Date: Fri, 6 Jun 2008 16:23:47 GMT (19kb)

Title: Stability of persistent currents in a Bose-Einstein condensate confined

in a toroidal trap

Authors: M. Ogren, G. M. Kavoulakis

Categories: cond-mat.other

Comments: 6 pages, 5 figures

\\

Motivated by recent experiments in Bose-Einstein condensed atoms that have

been confined in toroidal traps, we examine the stability of persistent

currents in such systems. We investigate the extent that the stability of these

currents may be tunable, and the possible difficulties in their creation and

detection.

\\ ( http://arxiv.org/abs/0806.1201 , 19kb)

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arXiv:0806.1220

Date: Fri, 6 Jun 2008 19:59:48 GMT (400kb)

Title: Quantum-Fluctuation-Driven Coherent Spin Dynamics in Small Condensates

Authors: Xiaoling Cui, Yupeng Wang and Fei Zhou

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\

We have studied quantum spin dynamics of small condensates of cold sodium

atoms. For a condensate initially prepared in a mean field ground state, we

show that coherent spin dynamics are {\em purely} driven by quantum

fluctuations of collective spin coordinates and can be tuned by quadratic

Zeeman coupling and magnetization. These dynamics in small condensates can be

probed in a high-finesse optical cavity where temporal behaviors of excitation

spectra of a coupled condensate-photon system reveal the time evolution of

populations of atoms at different hyperfine spin states.

\\ ( http://arxiv.org/abs/0806.1220 , 400kb)

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arXiv:0805.1402 (*cross-listing*)

Date: Fri, 9 May 2008 19:47:31 GMT (216kb)

Title: QND measurements and state preparation in quantum gases by light

detection

Authors: Igor B. Mekhov, Helmut Ritsch

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

Comments: 4 pages, 3 figures

\\

We consider light scattering from ultracold atoms trapped in an optical

lattice into a cavity. The measurement of photons leaking out the cavity

provides a quantum nondemolition (QND) access to various atomic variables.

Depending on the chosen geometry the time resolved light detection projects the

atomic quantum state to various atom-number squeezed and Schroedinger cat

states. Modifications of the atomic and light properties at a single quantum

trajectory are demonstrated. The quantum structure of final states can be

revealed by further observations of the same sample.

\\ ( http://arxiv.org/abs/0805.1402 , 216kb)

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arXiv:0806.1048

Date: Fri, 6 Jun 2008 19:32:20 GMT (53kb)

Title: Spin squeezing and entanglement

Authors: Geza Toth, Christian Knapp, Otfried G\"uhne, Hans J. Briegel

Categories: quant-ph

Comments: 13 pages including 6 figures and 2 tables, revtex4

\\

What is the relation between spin squeezing and entanglement? To clarify

this, we derive the full set of generalized spin squeezing inequalities for the

detection of entanglement. These are inequalities for the mean values and

variances of the collective angular momentum components J_k. They can be used

for the experimental detection of entanglement in a system of spin-1/2

particles in which the spins cannot be individually addressed. We present

various sets of inequalities that can detect all entangled states that can be

detected based on the knowledge of: (i) the mean values and variances of J_k in

three orthogonal directions, or (ii) the variances of J_k in three orthogonal

directions, or (iii) the mean values of J_k^2 in three orthogonal directions or

(iv) the mean values and variances of J_k in arbitrary directions. We compare

our inequalities to known spin squeezing entanglement criteria and discuss to

which extent spin squeezing is related to entanglement in the reduced two-qubit

states. Finally, we apply our criteria for entanglement detection in spin

models, showing that they can be used to detect bound entanglement in these

systems.

\\ ( http://arxiv.org/abs/0806.1048 , 53kb)

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arXiv:0806.1196

Date: Fri, 6 Jun 2008 16:03:57 GMT (142kb)

Title: Creating ultracold molecules by collisions with ultracold rare gas atoms

in an optical trap

Authors: P. Barletta, J. Tennyson, P. F. Barker

Categories: physics.atom-ph physics.chem-ph

Comments: 5 pages, 1 figure, 1 table, submitted for publication

\\

We study collisions of para-H$_2$ with five rare gas atomic species (He, Ne,

Ar, Kr and Xe) over the range from 1 K to 1 $\mu$ K and evaluate the

feasibility of sympathetic cooling H$_2$ with ultracold ground state rare gas

atoms co-trapped within a deep optical trap. Collision cross-sections over this

large temperature range show that all of these species could be used to cool

H$_2$ to ultracold temperatures and that argon and helium are the most

promising species for future experiments.

\\ ( http://arxiv.org/abs/0806.1196 , 142kb)

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arXiv:0806.1517

Date: Mon, 9 Jun 2008 18:47:15 GMT (842kb,D)

Title: Stirring trapped atoms into fractional quantum Hall puddles

Authors: Stefan K. Baur, Kaden R. A. Hazzard, and Erich J. Mueller (Cornell)

Categories: cond-mat.mes-hall cond-mat.other

Comments: 4 pages, 3 figures (13 subfigures)

\\

We theoretically explore the generation of few-body analogs of fractional

quantum Hall states. We consider an array of identical few-atom clusters

(n=2,3,4), each cluster trapped at the node of an optical lattice. By

temporally varying the amplitude and phase of the trapping lasers, one can

introduce a rotating deformation at each site. We analyze protocols for

coherently transferring ground state clusters into highly correlated states,

producing theoretical fidelities in excess of 99%.

\\ ( http://arxiv.org/abs/0806.1517 , 842kb)

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arXiv:0806.1295

Date: Sat, 7 Jun 2008 18:55:32 GMT (343kb)

Title: Giant formation rates of ultracold molecules via Feshbach Optimized

Photoassociation

Authors: Philippe Pellegrini, Marko Gacesa, and Robin C\^ot\'e

Categories: quant-ph

\\

Ultracold molecules offer a broad variety of applications, ranging from

metrology to quantum computing. However, forming "real" ultracold molecules,

{\it i.e.} in deeply bound levels, is a very difficult proposition. Here, we

show how photoassociation in the vicinity of a Feshbach resonance enhance

molecular formation rates by several orders of magnitude. We illustrate this

effect in heteronuclear systems, and find giant rate coefficients even in

deeply bound levels. We also give a simple analytical expression for the

photoassociation rates, and discuss future applications of the Feshbach

Optimized Photoassociation, or FOPA, technique.

\\ ( http://arxiv.org/abs/0806.1295 , 343kb)

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arXiv:0806.1479

Date: Mon, 9 Jun 2008 15:49:23 GMT (7kb)

Title: Exciton BCS or BEC state in a semiconductor bilayer system?

Authors: E. H. Martins Ferreira, Tathiana Moreira, M. C. Nemes

Categories: quant-ph

Comments: 4 pages

\\

We calculate the off-diagonal long range order (ODLRO) terms of the

exciton--exciton correlation function of a semiconductor bilayer system with

Coulomb interaction and a transverse magnetic field. We show that the formation

of a BEC state is very sensitive to the width of the interaction in momentum

space. This dependence is analytically derived and represents the key physical

ingredient for the formation (or not) of an exciton condensate state.

\\ ( http://arxiv.org/abs/0806.1479 , 7kb)

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arXiv:0806.1368

Date: Mon, 9 Jun 2008 03:36:56 GMT (59kb)

Title: Application of B-splines to determining eigen-spectrum of Feshbach

molecules

Authors: A. Derevianko, E. Luc-Koenig, and F. Masnou-Seeuws

Categories: physics.atom-ph physics.comp-ph

Comments: submitted to can j phys: Walter Johnson symposum

\\

The B-spline basis set method is applied to determining the rovibrational

eigen-spectrum of diatomic molecules. A particular attention is paid to a

challenging numerical task of an accurate and efficient description of the

vibrational levels near the dissociation limit (halo-state and Feshbach

molecules). Advantages of using B-splines are highlighted by comparing the

performance of the method with that of the commonly-used discrete variable

representation (DVR) approach. Several model cases, including the Morse

potential and realistic potentials with 1/R^3 and 1/R^6 long-range dependence

of the internuclear separation are studied. We find that the B-spline method is

superior to the DVR approach and it is robust enough to properly describe the

Feshbach molecules. The developed numerical method is applied to studying the

universal relation of the energy of the last bound state to the scattering

length. We numerically illustrate the validity of the quantum-defect-theoretic

formulation of such a relation for a 1/R^6 potential.

\\ ( http://arxiv.org/abs/0806.1368 , 59kb)

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arXiv:0806.1627

Date: Tue, 10 Jun 2008 10:39:49 GMT (96kb)

Title: Atom-atom correlations and relative number squeezing in dissociation of

spatially inhomogeneous molecular condensates

Authors: Magnus Ogren and K. V. Kheruntsyan

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

Comments: 4 pages, 2 figures

\\

We study atom-atom correlations and relative number squeezing in the

dissociation of a Bose-Einstein condensate (BEC) of molecular dimers made of

either bosonic or fermionic atom pairs. Our treatment addresses the role of the

spatial inhomogeneity of the molecular BEC on the strength of correlations in

the short time limit. We obtain explicit analytic results for the

density-density correlation functions in momentum space, and show that the

correlation widths and the degree of relative number squeezing are determined

merely by the shape of the molecular condensate.

\\ ( http://arxiv.org/abs/0806.1627 , 96kb)

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arXiv:0806.1688

Date: Tue, 10 Jun 2008 15:16:44 GMT (216kb)

Title: Anyons from fermions with conventional two-body interactions

Authors: Yue Yu, Yi Li

Categories: cond-mat.other cond-mat.str-el

Comments: 8 pages, 7 figures

\\

Emergent anyonic excitations are the key elements to reach the fault-tolerant

topological quantum computation, which was first recognized by Kitaev in the

study of the toric code model. However, it is difficult to realize these toric

codes in a practical system because of unconventional interactions in the model

Hamiltonian. We propose a two-component fermion model with conventional

interaction from which anyons emerge. We show that the low-lying excitations in

this model obey the same fusion rules as those of the toric code model and the

vortices are mutual semions. After switching on the mutual component

interaction between fermions, non-abelian anyons emerge. We discuss the

possible practical systems for these anyons and found the anyons may be

observed in systems of cold dipolar Fermi atoms, e.g., Ytterbium, and cold

dipolar fermionic heteronuclear molecules, e.g., $^{40}$K$^{87}$Rb, in optical

lattice. We can create and manipulate these anyons by laser beams acting on

lattice sites.

\\ ( http://arxiv.org/abs/0806.1688 , 216kb)

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arXiv:0806.1553

Date: Tue, 10 Jun 2008 18:07:52 GMT (673kb)

Title: Amplification of Fluctuations in a Spinor Bose Einstein Condensate

Authors: S. R. Leslie, J. Guzman, M. Vengalattore, J. D. Sau, M. L. Cohen, D.

M. Stamper-Kurn

Categories: quant-ph

\\

Dynamical instabilities due to spin-mixing collisions in a $^{87}$Rb F=1

spinor Bose-Einstein condensate are used as an amplifier of quantum spin

fluctuations. We demonstrate the spectrum of this amplifier to be tunable, in

quantitative agreement with mean-field calculations. We quantify the

microscopic spin fluctuations of the initially paramagnetic condensate by

applying this amplifier and measuring the resulting macroscopic magnetization.

The magnitude of these fluctuations is consistent with predictions of a

beyond-mean-field theory. The spinor-condensate-based spin amplifier is thus

shown to be nearly quantum-limited at a gain as high as 30 dB.

\\ ( http://arxiv.org/abs/0806.1553 , 673kb)

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arXiv:0806.1697

Date: Tue, 10 Jun 2008 15:59:29 GMT (667kb)

Title: Diffraction of fast atoms and molecules from surfaces

Authors: J. R. Manson, Hocine Khemliche, Philippe Roncin

Categories: physics.atom-ph

Comments: 37 pages including 3 figures

\\

Prompted by recent experimental developments, a theory of surface scattering

of fast atoms at grazing incidence is developed. The theory gives rise to a

quantum mechanical limit for ordered surfaces that describes coherent

diffraction peaks whose thermal attenuation is governed by a Debye-Waller

factor, however, this Debye-Waller factor has values much larger than would be

calculated using simple models. A classical limit for incoherent scattering is

obtained for high energies and temperatures. Between these limiting classical

and quantum cases is another regime in which diffraction features appear that

are broadened by the motion in the fast direction of the scattered beam but

whose intensity is not governed by a Debye-Waller factor. All of these limits

appear to be accessible within the range of currently available experimental

conditions.

\\ ( http://arxiv.org/abs/0806.1697 , 667kb)

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arXiv:0806.1747

Date: Tue, 10 Jun 2008 20:19:40 GMT (171kb)

Title: Exact quantum Monte Carlo study of one dimensional trapped fermions with

attractive contact interactions

Authors: Michele Casula, D. M. Ceperley, and Erich J. Mueller

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

Comments: 11 pages, 10 figures

\\

Using exact continuous quantum Monte Carlo techniques, we study the zero and

finite temperature properties of a system of harmonically trapped one

dimensional spin 1/2 fermions with short range interactions. Motivated by

experimental searches for modulated Fulde-Ferrel-Larkin-Ovchinikov states, we

systematically examine the impact of a spin imbalance on the density profiles.

We quantify the accuracy of the Thomas-Fermi approximation, finding that for

sufficiently large particle numbers (N > 100) it quantitatively reproduces most

features of the exact density profile. The Thomas-Fermi approximation fails to

capture small Friedel-like spin and density oscillations and overestimates the

size of the fully paired region in the outer shell of the trap. Based on our

results, we suggest a range of experimentally tunable parameters to maximize

the visibility of the double shell structure of the system and the

Fulde-Ferrel-Larkin-Ovchinikov state in the one dimensional harmonic trap.

Furthermore, we analyze the fingerprints of the attractive contact interactions

in the features of the momentum and pair momentum distributions.

\\ ( http://arxiv.org/abs/0806.1747 , 171kb)

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arXiv:0806.1761

Date: Tue, 10 Jun 2008 21:57:30 GMT (39kb)

Title: Exact Ground State Energy of Hubbard Rings in the Atomic Limit

Authors: W. B. Hodge, N. A. W. Holzwarth, W. C. Kerr

Categories: cond-mat.str-el

Comments: 4 pages, 4 figure files for 3 figures

\\

Making some reasonable assumptions, we derive an expression for the ground

state energy of a one-dimensional Hubbard ring in the atomic limit, valid for

systems of finite size. In doing so, we show that a straightforward solution to

equations derived by Lieb and Wu does not obtain the expected ground state

energy in this limit.

\\ ( http://arxiv.org/abs/0806.1761 , 39kb)

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arXiv:0806.1773

Date: Wed, 11 Jun 2008 00:51:43 GMT (62kb)

Title: Exact solution for strongly interacting Fermi gases in tight waveguides

Authors: Liming Guan, Shu Chen, Yupeng Wang, Zhong-Qi Ma

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

Comments: 4 pages, 3 figures

\\

We present an exact analytical solution of the fundamental systems of

quasi-one-dimensional spin-1/2 fermions with infinite repulsion for arbitrary

confining potential. The eigenfunctions are constructed by the combination of

Gireardeau's hard-core contacting boundary condition and group theoretical

method which guarantees the obtained states to be simultaneously the

eigenstates of $S$ and $S_z$ and fulfill the antisymmetry under odd

permutation. We show that the total ground-state density profile behaves like

the polarized noninteracting fermions, whereas the spin-dependent densities

display different properties for different spin configurations. We also discuss

the splitting of the ground states for large but finite repulsion.

\\ ( http://arxiv.org/abs/0806.1773 , 62kb)

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arXiv:0806.1777

Date: Wed, 11 Jun 2008 01:46:40 GMT (204kb)

Title: Spin echo in spinor dipolar Bose-Einstein condensates

Authors: Masashi Yasunaga and Makoto Tsubota

Categories: cond-mat.other

Comments: 4 pages, 5 figures

\\

We theoretically propose and numerically realize spin echo in a spinor

Bose--Einstein condensate (BEC). We investigate the influence on the spin echo

of phase separation of the condensate. The equation of motion of the spin

density exhibits two relaxation times. We use two methods to separate the

relaxation times and hence demonstrate a technique to reveal magnetic

dipole--dipole interactions in spinor BECs.

\\ ( http://arxiv.org/abs/0806.1777 , 204kb)

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arXiv:0806.1799

Date: Wed, 11 Jun 2008 09:17:21 GMT (196kb)

Title: Construction of localized atomic wave packets

Authors: S. Sree Ranjani, P. K. Panigrahi and A. K. Kapoor

Categories: cond-mat.other

Comments: 10 pages, 3 figures

\\

It is shown that highly localized solitons can be created in lower

dimensional Bose-Einstein condensates (BEC), trapped in a regular harmonic

trap, by temporally varying the trap frequency. A BEC trapped in such a trap

can be effectively used to construct a pulsed atomic laser emitting coherent

atomic wave packets. It is also shown that one has complete control over the

spatio-temporal dynamics of the solitons. The dynamics of these solitons are

compared with those constructed in a BEC where the trap frequency is constant.

\\ ( http://arxiv.org/abs/0806.1799 , 196kb)

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arXiv:0806.1885

Date: Wed, 11 Jun 2008 14:55:47 GMT (765kb)

Title: Unitary polarized Fermi gas under adiabatic rotation

Authors: I. Bausmerth, A. Recati, S. Stringari

Categories: cond-mat.other

Comments: 8 pages, 10 figures

\\

We discuss the effect of an adiabatic rotation on the phase separation

between the superfluid and normal component of a trapped polarized Fermi gas at

unitarity and zero temperature, under the assumption that quantized vortices

are not formed. We show that the Chandrasekhar-Clogston limit

$n_{\downarrow}/\n_{\uparrow}$ characterizing the local polarization in the

normal phase at the interface is enhanced by the rotation as a consequence of

the centrifugal effect. The density profiles (local and column integral) of the

two spin species are calculated as a function of the angular velocity for

different values of the polarization. The critical value of the angular

velocity at which the superfluid exhibits a spontaneous quadrupole deformation

is also calculated for the unpolarized case.

\\ ( http://arxiv.org/abs/0806.1885 , 765kb)

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arXiv:0806.1889

Date: Wed, 11 Jun 2008 14:52:36 GMT (19kb)

Title: Hydrodynamic equations of anisotropic, polarized and inhomogeneous

superfluid vortex tangles

Authors: David Jou, Maria Stella Mongiov\`i, Michele Sciacca

Categories: cond-mat.other

Comments: 17 pages

\\

We include the effects of anisotropy and polarization in the hydrodynamics of

inhomogeneous vortex tangles, thus generalizing the well known

Hall-Vinen-Bekarevich-Khalatnikov equations, which do not take them in

consideration. These effects contribute to the mutual friction force ${\bf

F}_{ns}$ between normal and superfluid components and to the vortex tension

force $\rho_s{\bf T}$. These equations are complemented by an evolution

equation for the vortex line density, which takes into account these

contributions.

\\ ( http://arxiv.org/abs/0806.1889 , 19kb)

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arXiv:0806.1789

Date: Wed, 11 Jun 2008 05:18:29 GMT (322kb)

Title: Towards a guided atom interferometer based on a superconducting atom

chip

Authors: T. Mueller, X. Wu, A. Mohan, A. Eyvazov, Y. Wu and R. Dumke

Categories: physics.atom-ph

Comments: 14 pages, 7 figures, accepted for New Journal of Physics

\\

We evaluate the realization of a novel geometry of a guided atom

interferometer based on a high temperature superconducting microstructure. The

interferometer type structure is obtained with a guiding potential realized by

two current carrying superconducting wires in combination with a closed

superconducting loop sustaining a persistent current. We present the layout and

realization of our superconducting atom chip. By employing simulations we

discuss the critical parameters of the interferometer guide in particular near

the splitting regions of the matter waves. Based on measurements of the

relevant chip properties we discuss the application of a compact and reliable

on-chip atom interferometer.

\\ ( http://arxiv.org/abs/0806.1789 , 322kb)

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arXiv:0806.1991

Date: Thu, 12 Jun 2008 03:08:20 GMT (696kb)

Title: Roton softening and supersolidity in Rb spinor condensates

Authors: R. W. Cherng, E. Demler

Categories: cond-mat.other

Comments: 8 pages, 5 figures

\\

Superfluids with a tendency towards periodic crystalline order have both a

phonon and roton like spectrum of collective modes. The softening of the roton

spectrum provides one route to a supersolid. We show that roton softening

occurs in 87Rb spinor condensates once dipolar interactions and spin dynamics

are taken into account. By including the effects of a quasi-two-dimensional

geometry and rapid Larmor precession, we show a dynamical instability develops

in the collective mode spectrum at finite wavevectors. We construct phase

diagrams showing a variety of instabilities as a function of the direction of

the magnetic field and strength of the quadratic Zeeman shift. Our results

provide a possible explanation of current experiments in the Berkeley group

Phys. Rev. Lett. 100:170403 (2008).

\\ ( http://arxiv.org/abs/0806.1991 , 696kb)

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arXiv:0806.2012

Date: Thu, 12 Jun 2008 07:09:48 GMT (261kb)

Title: Uniformly frustrated bosonic Josephson-junction arrays

Authors: Kenichi Kasamatsu

Categories: cond-mat.stat-mech cond-mat.mes-hall

Comments: 5 pages, 2 figures

\\

We derive an uniformly frustrated XY model that describes two-dimensional

Josephson junction arrays consisting of rotating Bose-Einstein condensates

trapped by both a harmonic trap and a corotating deep optical lattice. The

harmonic trap makes the coupling constant of the model have a nonuniform

parabolic dependance. We study the ground state through Monte Carlo simulations

in a wide range of the frustration parameter $f$, revealing a rich variety of

vortex patterns.

\\ ( http://arxiv.org/abs/0806.2012 , 261kb)

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arXiv:0806.2077

Date: Thu, 12 Jun 2008 13:42:38 GMT (127kb)

Title: Vortex dynamics in trapped Bose-Einstein condensate

Authors: E. J. M. Madarassy and C. F. Barenghi

Categories: cond-mat.stat-mech

Comments: 16 pages, 18 figures, accepted to JLTP

\\

We perform numerical simulations of vortex motion in a trapped Bose-Einstein

condensate by solving the two-dimensional Gross-Pitaevskii Equation in the

presence of a simple phenomenological model of interaction between the

condensate and the finite temperature thermal cloud. At zero temperature, the

trajectories of a single, off - centred vortex precessing in the condensate,

and of a vortex - antivortex pair orbiting within the trap, excite acoustic

emission. At finite temperatures the vortices move to the edge of the

condensate and vanish. By fitting the finite -temperature trajectories, we

relate the phenomenological damping parameter to the friction coefficients

$\alpha$ and $\alpha^{'}$, which are used to describe the interaction between

quantised vortices and the normal fluid in superfluid helium.

\\ ( http://arxiv.org/abs/0806.2077 , 127kb)

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arXiv:0806.2093

Date: Thu, 12 Jun 2008 15:06:36 GMT (357kb)

Title: Detuning effects in the vertical cold-atom micromaser

Authors: John Martin and Thierry Bastin

Categories: quant-ph

Comments: 11 pages

Journal-ref: Eur. Phys. J. D 48, 301 (2008)

DOI: 10.1140/epjd/e2008-00108-1

\\

The quantum theory of the cold atom micromaser including the effects of

gravity is established in the general case where the cavity mode and the atomic

transition frequencies are detuned. We show that atoms which classically would

not reach the interaction region are able to emit a photon inside the cavity.

The system turns out to be extremely sensitive to the detuning and in

particular to its sign. A method to solve the equations of motion for non

resonant atom-field interaction and arbitrary cavity modes is presented.

\\ ( http://arxiv.org/abs/0806.2093 , 357kb)

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arXiv:0806.1982

Date: Thu, 12 Jun 2008 00:45:47 GMT (160kb)

Title: Universal resonant ultracold molecular scattering

Authors: Vladimir Roudnev and Michael Cavagnero

Categories: physics.atom-ph physics.atm-clus

Comments: 4 pages, 4 figures, 1 table

\\

The elastic scattering amplitudes of indistinguishable, bosonic,

strongly-polar molecules possess near-threshold resonance features that can be

tuned with an applied electric field. An adiabatic description of ultracold

collisions of field-aligned molecules provides an elementary and complete

interpretation and classification of these resonant states; including three

series of threshold bound states, shape resonances, and mixed Feshbach/shape

resonances. Small tunneling amplitudes for the resonant states result in strong

correlations between the magnitude of total elastic cross sections and the

isotropy, or lack thereof, of threshold differential cross-sections.

Implications of universal scaling for the formation and trapping of dilute

quantum degenerate gases are discussed.

\\ ( http://arxiv.org/abs/0806.1982 , 160kb)

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arXiv:0805.1507

replaced with revised version Thu, 5 Jun 2008 21:58:43 GMT (265kb)

Title: Maximizing the Neel temperature of fermions in a simple-cubic optical

lattice

Authors: C.J.M. Mathy and David A. Huse

Categories: cond-mat.str-el

Comments: 4 pages, 3 figures, minor changes

\\ ( http://arxiv.org/abs/0805.1507 , 265kb)

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arXiv:0709.2924

replaced with revised version Fri, 6 Jun 2008 00:54:24 GMT (47kb)

Title: Feshbach resonances in ultracold ^{6,7}Li + ^{23}Na atomic mixtures

Authors: Marko Gacesa, Philippe Pellegrini, and Robin C\^ot\'e

Categories: physics.atom-ph

Comments: 4 pages, 3 figures

\\ ( http://arxiv.org/abs/0709.2924 , 47kb)

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arXiv:cond-mat/0405182

replaced with revised version Sat, 7 Jun 2008 02:43:52 GMT (196kb)

Title: Vortex lattice stability and phase coherence in three-dimensional

rapidly rotating Bose condensates

Authors: S. Andrew Gifford, Gordon Baym

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

Comments: 10 pages, 2 figures, Changes include the addition of the particle

density - vortex density coupling and the correct value of the shear modulus

Journal-ref: Phys. Rev. A 70, 033602 (2004)

\\ ( http://arxiv.org/abs/cond-mat/0405182 , 196kb)

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arXiv:0712.0880

replaced with revised version Mon, 9 Jun 2008 04:33:43 GMT (248kb)

Title: New Density Wave Ground States and Dynamical Phase Transitions in an

Optical Lattice

Authors: Manan Vyas, Priyam Das, and Prasanta K. Panigrahi

Categories: cond-mat.other

Comments: 4 pages

\\ ( http://arxiv.org/abs/0712.0880 , 248kb)

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arXiv:0804.1277

replaced with revised version Sun, 8 Jun 2008 15:17:01 GMT (8kb)

Title: Hydrodynamics of Bose and Fermi superfluids at zero temperature: the

superfluid nonlinear Schrodinger equation

Authors: Luca Salasnich (CNR-INFM and CNISM, University of Padua)

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

Comments: 4 pages, no figures, prepared for the Special Issue of Laser Physics:

Physics of Cold Trapped Atoms; in the second version corrected some typos

\\ ( http://arxiv.org/abs/0804.1277 , 8kb)

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arXiv:0712.0880

replaced with revised version Tue, 10 Jun 2008 04:47:08 GMT (248kb)

Title: New Density Wave Ground States and Dynamical Phase Transitions in an

Optical Lattice

Authors: Manan Vyas, Priyam Das, and Prasanta K. Panigrahi

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\ ( http://arxiv.org/abs/0712.0880 , 248kb)

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arXiv:0803.4352

replaced with revised version Tue, 10 Jun 2008 12:15:58 GMT (282kb,D)

Title: Experimental observation of oscillating and interacting matter wave dark

solitons

Authors: A. Weller, J.P. Ronzheimer, C. Gross, D.J. Frantzeskakis, G.

Theocharis, P.G. Kevrekidis, J. Esteve, and M.K. Oberthaler

Categories: quant-ph cond-mat.other

Comments: 5 pages, 3 figures

\\ ( http://arxiv.org/abs/0803.4352 , 282kb)

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arXiv:0805.3663

replaced with revised version Tue, 10 Jun 2008 17:10:19 GMT (513kb)

Title: Phase diagram, extended domain walls, and soft collective modes in a

three component fermionic superfluid

Authors: G. Catelani, E. A. Yuzbashyan

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

Comments: 16 pages, 6 figures. References added, typos corrected

\\ ( http://arxiv.org/abs/0805.3663 , 513kb)

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arXiv:0801.1815

replaced with revised version Wed, 11 Jun 2008 13:18:49 GMT (40kb)

Title: Superfluid pairing between fermions with unequal masses

Authors: M.A. Baranov, C. Lobo, and G.V. Shlyapnikov

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

Comments: 21 pages, 9 figures, 1 table, discussions added

\\ ( http://arxiv.org/abs/0801.1815 , 40kb)

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arXiv:0804.2610

replaced with revised version Wed, 11 Jun 2008 13:55:38 GMT (64kb)

Title: Phase diagram and binding energy of interacting Bose gases

Authors: M. M\"annel, K. Morawetz, M. Schreiber, P. Lipavsk\'y

Categories: cond-mat.stat-mech

\\ ( http://arxiv.org/abs/0804.2610 , 64kb)

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arXiv:physics/0701272

replaced with revised version Tue, 10 Jun 2008 20:15:38 GMT (659kb)

Title: Experimental single-impulse magnetic focusing of launched cold atoms

Authors: David A. Smith, Aidan S. Arnold, Matthew J. Pritchard and Ifan G.

Hughes

Categories: physics.atom-ph physics.optics

Comments: Revised to incorporate referee suggestions, final version

Journal-ref: J. Phys. B 41, 125302 (2008)

DOI: 10.1088/0953-4075/41/12/125302

\\ ( http://arxiv.org/abs/physics/0701272 , 659kb)

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arXiv:0804.2068

replaced with revised version Thu, 12 Jun 2008 09:50:27 GMT (150kb)

Title: Self-trapping of Bose-Einstein condensates expanding into shallow

optical lattices

Authors: M. Rosenkranz, D. Jaksch, F. Y. Lim, W. Bao

Categories: quant-ph cond-mat.other

Comments: 7 pages, 5 figures, RevTeX4. Published version. Changed title, minor

clarifications, added two references, also added arXiv ids for most

references

Journal-ref: Phys. Rev. A 77, 063607 (2008)

DOI: 10.1103/PhysRevA.77.063607

\\ ( http://arxiv.org/abs/0804.2068 , 150kb)

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Till next time,

Matt.

-- ========================================================================= Dr M. J. Davis, Senior Lecturer in Physics School of Physical Sciences, email: mdavis_at_physics.uq.edu.au University of Queensland, ph : +61 7 334 69824 Brisbane, QLD 4072, fax : +61 7 336 51242 Australia. http://www.physics.uq.edu.au/people/mdavis/ ========================================================================= 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 =========================================================================Received on Fri Jul 04 2008 - 08:30:56 EST

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