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

Date: Mon, 10 Nov 2008 12:05:03 +1000

Date: Mon, 10 Nov 2008 12:05:03 +1000

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

Hi all,

This week there were 23 new preprints and 7 replacements:

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arXiv:0810.5625

Date: Fri, 31 Oct 2008 06:25:59 GMT (57kb)

Title: Finite-frequency dynamics of vortex loops at the $^4$He superfluid phase

transition

Authors: Gary A. Williams

Categories: cond-mat.stat-mech

Comments: 4 pages, submitted to Journal of Physics: Conference Series

(Proceedings of LT25)

\\

The finite-frequency dynamics of the $^4$He superfluid phase transition can

be formulated in terms of the response of thermally excited vortex loops to an

oscillating flow field. The key parameter is the Hausdorff fractal dimension

$d_H$ of the loops, which affects the dynamics because the frictional force on

a loop is proportional to the total perimeter $P$ of the loop, which varies as

$P \sim a^{d_H}$ where $a$ is the loop diameter. Solving the 3D Fokker-Planck

equation for the loop response at frequency $\omega $ yields a superfluid

density which varies at $T_{\lambda}$ as $\omega^{1/(d_H -1)}$. This power-law

variation with $\omega$ agrees with the scaling form found by Fisher, Fisher,

and Huse, since the dynamic exponent $z$ is identified as $z = d_H-1$. Flory

scaling for the self-avoiding loops gives a fractal dimension in terms of the

space dimension $d$ as $d_H = (d+2)/2$, yielding $z = d/2 = 3/2$ for d = 3, in

complete agreement with dynamic scaling.

\\ ( http://arxiv.org/abs/0810.5625 , 57kb)

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arXiv:0810.5687

Date: Fri, 31 Oct 2008 13:46:56 GMT (334kb)

Title: Incoherence of Bose-Einstein condensates at supersonic speeds due to

quantum noise

Authors: R.G. Scott and D.A.W. Hutchinson

Categories: cond-mat.other

Comments: 6 pages, 5 figures

\\

We calculate the effect of quantum noise in supersonic transport of

Bose-Einstein condensates. When an obstacle obstructs the flow of atoms,

quantum fluctuations cause atoms to be scattered incoherently into random

directions. This suppresses the propagation of Cherenkov radiation, creating

quantum turbulence and a crescent of incoherent atoms around the obstacle. We

observe similar dynamics if the BEC is stirred by a laser beam: crescents of

incoherent atoms are emitted from the laser's turning-points. Finally, we

investigate supersonic flow through a disordered potential, and find that the

quantum fluctuations generate an accumulation of incoherent atoms as the

condensate enters the disorder.

\\ ( http://arxiv.org/abs/0810.5687 , 334kb)

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arXiv:0810.5690

Date: Fri, 31 Oct 2008 14:10:33 GMT (700kb)

Title: Rayleigh superradiance and dynamic Bragg gratings in an end-pumped

Bose-Einstein condensate

Authors: A. Hilliard, F. Kaminski, R. le Targat, C. Olausson, E. S. Polzik, and

J. H. M\"uller

Categories: cond-mat.other

Comments: 5 pages, 3 figures

\\

We study experimentally superradiant Rayleigh scattering from a Bose-Einstein

condensate (BEC) in a new parameter regime where pump depletion and the

exchange of photons between the endfire modes are important. Through

experiments and simulations we show that collective atom light coupling leads

to the self-organized formation of dynamic Bragg gratings within the sample.

These gratings lead to an efficient back-scattering of pump photons and optical

resonator structures within the BEC.

\\ ( http://arxiv.org/abs/0810.5690 , 700kb)

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arXiv:0810.5726

Date: Fri, 31 Oct 2008 16:16:49 GMT (68kb)

Title: Control of the persistent currents in two interacting quantum rings

through the Coulomb interaction and inter-ring tunneling

Authors: L. K. Castelano, G.-Q. Hai, B. Partoens and F. M. Peeters

Categories: cond-mat.mes-hall

Comments: accepted for publication in Phys. Rev. B

\\

The persistent current in two vertically coupled quantum rings containing few

electrons is studied. We find that the Coulomb interaction between the rings in

the absence of tunneling affects the persistent current in each ring and the

ground state configurations. Quantum tunneling between the rings alters

significantly the ground state and the persistent current in the system.

\\ ( http://arxiv.org/abs/0810.5726 , 68kb)

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arXiv:0810.5744

Date: Fri, 31 Oct 2008 17:49:38 GMT (423kb)

Title: Dark state experiments with ultracold, deeply-bound triplet molecules

Authors: Florian Lang, Christoph Strauss, Klaus Winkler, Tetsu Takekoshi,

Rudolf Grimm, Johannes Hecker Denschlag

Categories: cond-mat.other

Comments: 20 pages, 9 figures

\\

We examine dark quantum superposition states of weakly bound Rb2 Feshbach

molecules and tightly bound triplet Rb2 molecules in the rovibrational ground

state, created by subjecting a pure sample of Feshbach molecules in an optical

lattice to a bichromatic Raman laser field. We analyze both experimentally and

theoretically the creation and dynamics of these dark states. Coherent

wavepacket oscillations of deeply bound molecules in lattice sites, as observed

in one of our previous experiments, are suppressed due to laser-induced phase

locking of molecular levels. This can be understood as the appearance of a

novel multilevel dark state. In addition, the experimental methods developed

help to determine important properties of our coupled atom / laser system.

\\ ( http://arxiv.org/abs/0810.5744 , 423kb)

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arXiv:0810.5703

Date: Fri, 31 Oct 2008 15:02:29 GMT (522kb)

Title: Stimulating the production of deeply bound RbCs molecules with laser

pulses: the role of spin-orbit coupling in forming ultracold molecules

Authors: Subhas Ghosal, Richard J. Doyle, Christiane P. Koch and Jeremy M.

Hutson

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

\\

We investigate the possibility of forming deeply bound ultracold RbCs

molecules by a two-color photoassociation experiment. We compare the results

with those for Rb_2 in order to understand the characteristic differences

between heteronuclear and homonuclear molecules. The major differences arise

from the different long-range potential for excited states. Ultracold 85Rb and

133Cs atoms colliding on the X^1Sigma+ potential curve are initially

photoassociated to form excited RbCs molecules in the region below the Rb(5S) +

Cs(6P_1/2) asymptote. We explore the nature of the Omega=0^+ levels in this

region, which have mixed A^1Sigma^+ and b^3Pi character. We then study the

quantum dynamics of RbCs by a time-dependent wavepacket (TDWP) approach. A

wavepacket is formed by exciting a few vibronic levels and is allowed to

propagate on the coupled electronic potential energy curves. For a detuning of

7.5 cm-1, the wavepacket for RbCs reaches the short-range region in about 13

ps, which is significantly faster than for the homonuclear Rb_2 system; this is

mostly because of the absence of an R^-3 long-range tail in the excited-state

potential curves for heteronuclear systems. We give a simple semiclassical

formula that relates the time taken to the long-range potential parameters. For

RbCs, in contrast to Rb_2, the excited-state wavepacket shows a substantial

peak in singlet density near the inner turning point, and this produces a

significant probability of deexcitation to form ground-state molecules bound by

up to 1500 cm-1. Our analysis of the role of spin-orbit coupling concerns the

character of the mixed states in general and is important for both

photoassociation and stimulated Raman deexcitation.

\\ ( http://arxiv.org/abs/0810.5703 , 522kb)

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arXiv:0810.5738

Date: Fri, 31 Oct 2008 17:26:55 GMT (139kb)

Title: Two-photon coherent control of femtosecond photoassociation

Authors: Christiane P. Koch, Mamadou Ndong, Ronnie Kosloff

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

\\

Photoassociation with short laser pulses has been proposed as a technique to

create ultracold ground state molecules. A broad-band excitation seems the

natural choice to drive the series of excitation and deexcitation steps

required to form a molecule in its vibronic ground state from two scattering

atoms. First attempts at femtosecond photoassociation were, however, hampered

by the requirement to eliminate the atomic excitation leading to trap

depletion. On the other hand, molecular levels very close to the atomic

transition are to be excited. The broad bandwidth of a femtosecond laser then

appears to be rather an obstacle. To overcome the ostensible conflict of

driving a narrow transition by a broad-band laser, we suggest a two-photon

photoassociation scheme. In the weak-field regime, a spectral phase pattern can

be employed to eliminate the atomic line. When the excitation is carried out by

more than one photon, different pathways in the field can be interfered

constructively or destructively. In the strong-field regime, a temporal phase

can be applied to control dynamic Stark shifts. The atomic transition is

suppressed by choosing a phase which keeps the levels out of resonance. We

derive analytical solutions for atomic two-photon dark states in both the

weak-field and strong-field regime. Two-photon excitation may thus pave the way

toward coherent control of photoassociation. Ultimately, the success of such a

scheme will depend on the details of the excited electronic states and

transition dipole moments. We explore the possibility of two-photon femtosecond

photoassociation for alkali and alkaline-earth metal dimers and present a

detailed study for the example of calcium.

\\ ( http://arxiv.org/abs/0810.5738 , 139kb)

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arXiv:0810.5745

Date: Fri, 31 Oct 2008 18:10:22 GMT (7kb)

Title: Observation of the Nuclear Magnetic Octupole Moment of 87Rb from

Spectroscopic Measurements of Hyperfine Intervals

Authors: Vladislav Gerginov, Carol E. Tanner and W. R. Johnson

Categories: physics.atom-ph

\\

The magnetic octupole moment of 87Rb is determined from hyperfine intervals

in the 5p 2P[3/2] state measured by Ye et al. [Opt. Lett. 21, 1280 (1996)].

Hyperfine constants A = 84.7189(22) MHz, B = 12.4942(43) MHz, and C = -0.12(09)

kHz are obtained from the published measurements. The existence of a

significant value for C indicates the presence of a nuclear magnetic octupole

moment Omega. Combining the hyperfine constants with atomic structure

calculations, we obtain Omega = -0.58(39) (b muN). Second-order corrections

arising from interaction with the nearby 5p 2P[1/2] state are found to be

insignificant.

\\ ( http://arxiv.org/abs/0810.5745 , 7kb)

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arXiv:0811.0314

Date: Mon, 3 Nov 2008 14:59:43 GMT (158kb)

Title: Predicting scattering properties of ultracold atoms: adiabatic

accumulated phase method and mass scaling

Authors: B.J. Verhaar, E.G.M. van Kempen, S.J.J.M.F. Kokkelmans

Categories: cond-mat.other

Comments: 14 pages, 9 figures

\\

Ultracold atoms are increasingly used for high precision experiments that can

be utilized to extract accurate scattering properties. This calls for a

stronger need to improve on the accuracy of interatomic potentials, and in

particular the usually rather inaccurate inner-range potentials. A boundary

condition for this inner range can be conveniently given via the accumulated

phase method. However, in this approach one should satisfy two conditions,

which are in principle conflicting, and the validity of these approximations

comes under stress when higher precision is required. We show that a better

compromise between the two is possible by allowing for an adiabatic change of

the hyperfine mixing of singlet and triplet states for interatomic distances

smaller than the separation radius. A mass scaling approach to relate

accumulated phase parameters in a combined analysis of isotopically related

atom pairs is described in detail and its accuracy is estimated, taking into

account both Born-Oppenheimer and WKB breakdown. We demonstrate how numbers of

singlet and triplet bound states follow from the mass scaling.

\\ ( http://arxiv.org/abs/0811.0314 , 158kb)

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arXiv:0811.0045

Date: Fri, 31 Oct 2008 23:44:53 GMT (1171kb)

Title: Cavity QED characterization of many-body atomic states in double-well

potentials -- The role of dissipation

Authors: W. Chen and P. Meystre

Categories: quant-ph

Comments: 8 pages, 15 figures

\\

When an incident light beam is scattered off a sample of ultracold atoms

trapped in an optical lattice, the statistical properties of the

retro-reflected field contain information about the quantum state of the atoms,

and permit for example to distinguish between atoms in a superfluid and a Mott

insulator state. This paper extends our previous analysis of this problem to

include the effects of cavity damping. We use a Monte Carlo wave function

method to determine the two-time correlation function and time-dependent

physical spectrum of the retro-reflected field in the case of a simple two-well

lattice. We also analyze quantitatively the entanglement between the atoms and

the light field for atoms in a Mott insulator and a superfluid state.

\\ ( http://arxiv.org/abs/0811.0045 , 1171kb)

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arXiv:0811.0264

Date: Mon, 3 Nov 2008 11:17:13 GMT (2059kb)

Title: Two-photon gateway in one-atom cavity quantum electrodynamics

Authors: A. Kubanek, A. Ourjoumtsev, I. Schuster, M. Koch, P.W.H. Pinkse, K.

Murr, G. Rempe

Categories: quant-ph

Comments: PRL, 4 figures

\\

Single atoms absorb and emit light from a resonant laser beam photon by

photon. We show that a single atom strongly coupled to an optical cavity can

absorb and emit resonant photons in pairs. The effect is observed in a photon

correlation experiment on the light transmitted through the cavity. We find

that the atom-cavity system transforms a random stream of input photons into a

correlated stream of output photons, thereby acting as a two-photon gateway.

The phenomenon has its origin in the quantum anharmonicity of the energy

structure of the atom-cavity system. Future applications could include the

controlled interaction of two photons by means of one atom.

\\ ( http://arxiv.org/abs/0811.0264 , 2059kb)

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arXiv:0811.0397

Date: Mon, 3 Nov 2008 21:09:28 GMT (538kb)

Title: Ground State Phase Diagram of the Two-Component Bose-Hubbard Model

Authors: \c{S}.G. S\"oyler, B. Capogrosso-Sansone, N.V. Prokof'ev, B.V.

Svistunov

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

Comments: 4 pages, 3 figures

\\

We have performed path integral Monte Carlo simulations of the two-component

hard-core Bose-Hubbard model on a square lattice at half-integer filling factor

for each component. This system can be realized experimentally with

heteronuclear bosonic mixtures in optical lattices with tunable interspecies

interactions. Our results disagree with preexisting analytical treatments both

quantitatively and qualitatively. We reveal the existence of an additional

solid+superfluid phase for strong anisotropy between the hopping amplitudes

which radically changes the topology of the ground-state phase diagram. The new

phase is a direct consequence of effective interactions between "heavy" atoms

mediated by the "light" superfluid component. Remarkably, mediated interactions

are sign-alternating and thus lead to a rich variety of yet to be discovered

quantum phases.

\\ ( http://arxiv.org/abs/0811.0397 , 538kb)

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arXiv:0811.0555

Date: Tue, 4 Nov 2008 17:05:51 GMT (61kb)

Title: Three-Component Fermi Gas in a one-dimensional Optical Lattice

Authors: P. Azaria, S. Capponi, P. Lecheminant

Categories: cond-mat.str-el

Comments: 4 pages, 3 figures

\\

We investigate the effect of the anisotropy between the s-wave scattering

lengths of a three-component atomic Fermi gas loaded into a one-dimensional

optical lattice. We find four different phases which support trionic

instabilities made of bound states of three fermions. These phases distinguish

themselves by the relative phases between the 2$k_F$ atomic density waves

fluctuations of the three species. At small enough densities or strong

anisotropies we give further evidences for a decoupling and the stabilization

of more conventional BCS phases. Finally our results are discussed in light of

a recent experiment on $^{6}$Li atoms.

\\ ( http://arxiv.org/abs/0811.0555 , 61kb)

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arXiv:0811.0410

Date: Tue, 4 Nov 2008 01:04:07 GMT (2573kb)

Title: The influence of optical molasses in loading a shallow optical trap

Authors: Mathew S. Hamilton, Anthony R. Gorges and Jacob L. Roberts

Categories: physics.atom-ph

Comments: 7 pages, 5 figures

\\

We have examined loading of 85Rb atoms into a shallow Far-Off-Resonance Trap

(FORT) from an optical molasses and compared it to loading from a

Magneto-Optical Trap (MOT). We found that substantially more atoms could be

loaded into the FORT via an optical molasses as compared to loading from the

MOT alone. To determine why this was the case, we measured the rate of atoms

loaded into the FORT and the losses from the FORT during the loading process.

For both MOT and molasses loading, we examined atom load rate and losses over a

range of detunings as well as hyperfine pump powers. We found that the losses

induced during MOT loading were essentially the same as the losses induced

during molasses loading at the same MOT/molasses detuning. In contrast, load

rate of the molasses was higher than that of a MOT at a given detuning. This

caused the optical molasses to be able to load more atoms than the MOT.

Optimization of FORT loading form an optical molasses improved the number of

atoms we could trap by a factor of two over that of optimal loading from a MOT.

\\ ( http://arxiv.org/abs/0811.0410 , 2573kb)

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arXiv:0811.0624

Date: Wed, 5 Nov 2008 11:49:18 GMT (32kb)

Title: Spectral function and quasi-particle damping of interacting bosons in

two dimensions

Authors: Andreas Sinner, Nils Hasselmann, and Peter Kopietz

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\

We employ the functional renormalization group to study dynamical properties

of the two-dimensional Bose gas. Our approach is free of infrared divergences,

which plague the usual diagrammatic approaches, and is consistent with the

exact Nepomnyashchy identity, which states that the anomalous self-energy

vanishes at zero frequency and momentum. We recover the correct infrared

behavior of the propagators and present explicit results for the spectral

line-shape, from which we extract the quasi-particle dispersion and damping.

\\ ( http://arxiv.org/abs/0811.0624 , 32kb)

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arXiv:0811.0671

Date: Wed, 5 Nov 2008 09:02:37 GMT (848kb)

Title: All-Optical Formation of Quantum Degenerate Mixtures

Authors: Takeshi Fukuhara, Seiji Sugawa, Yosuke Takasu, and Yoshiro Takahashi

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\

We report the realization of quantum degenerate mixed gases of ytterbium (Yb)

isotopes using all-optical methods. We have succeeded in cooling attractively

interacting 176Yb atoms via sympathetic cooling down to below the Bose-Einstein

transition temperature, coexisting with a stable condensate of 174Yb atoms with

a repulsive interaction. We have observed a rapid atom loss in 176Yb atoms

after cooling down below the transition temperature, which indicates the

collapse of a 176Yb condensate. The sympathetic cooling technique has been

applied to cool a 173Yb-174Yb Fermi-Bose mixture to the quantum degenerate

regime.

\\ ( http://arxiv.org/abs/0811.0671 , 848kb)

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arXiv:0811.0770

Date: Wed, 5 Nov 2008 16:35:33 GMT (75kb)

Title: Enhanced paraconductivity-like fluctuations in the radio frequency

spectra of ultracold Fermi atoms

Authors: Pierbiagio Pieri, Andrea Perali, Giancarlo Calvanese Strinati

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

Comments: 17 pages, 5 figures

\\

Ultracold Fermi atoms allow the realization of the crossover from

Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose- Einstein

condensation (BEC), by varying with continuity the attraction between fermions

of different species. In this context, radio frequency (RF) spectroscopy

provides a microscopic probe to infer the nature of fermionic pairing. In the

strongly-interacting regime, this pairing affects a wide temperature range

comprising the critical temperature T_c, in analogy to the pseudogap physics

for high-temperature superconductors. By including what are known in

superconductors as "paraconductivity" fluctuations, here we calculate the RF

spectra above T_c for fermions with balanced populations and compare them with

available experimental data, thus revealing that the role of these fluctuations

is considerably enhanced with respect to superconductors. In addition, we

extract from the spectra an energy scale associated with pairing and relate it

to a universal quantity recently introduced for Fermi gases.

\\ ( http://arxiv.org/abs/0811.0770 , 75kb)

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arXiv:0811.0695

Date: Wed, 5 Nov 2008 10:56:21 GMT (505kb,D)

Title: Dark resonances for ground state transfer of molecular quantum gases

Authors: Manfred J. Mark, Johann G. Danzl, Elmar Haller, Mattias Gustavsson,

Nadia Bouloufa, Olivier Dulieu, Houssam Salami, Tom Bergeman, Helmut Ritsch,

Russell Hart and Hanns-Christoph N\"agerl

Categories: quant-ph

Comments: 7 pages, 4 figures

\\

One possible way to produce ultracold, high-phase-space-density quantum gases

of molecules in the rovibronic ground state is given by molecule association

from quantum-degenerate atomic gases on a Feshbach resonance and subsequent

coherent optical multi-photon transfer into the rovibronic ground state. In

ultracold samples of Cs_2 molecules, we observe two-photon dark resonances that

connect the intermediate rovibrational level |v=73,J=2> with the rovibrational

ground state |v=0,J=0> of the singlet $X^1\Sigma_g^+$ ground state potential.

For precise dark resonance spectroscopy we exploit the fact that it is possible

to efficiently populate the level |v=73,J=2> by two-photon transfer from the

dissociation threshold with the stimulated Raman adiabatic passage (STIRAP)

technique. We find that at least one of the two-photon resonances is

sufficiently strong to allow future implementation of coherent STIRAP transfer

of a molecular quantum gas to the rovibrational ground state |v=0,J=0>.

\\ ( http://arxiv.org/abs/0811.0695 , 505kb)

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arXiv:0811.0844

Date: Wed, 5 Nov 2008 23:51:25 GMT (15kb)

Title: On the spin-liquid phase of one dimensional spin-1 bosons

Authors: F.H.L. Essler, G.V. Shlyapnikov and A.M. Tsvelik

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

Comments: 17 pages

\\

We consider a model of one dimensional spin-1 bosons with repulsive

density-density interactions and antiferromagnetic exchange. We show that the

low energy effective field theory is given by a spin-charge separated theory of

a Tomonaga-Luttinger Hamiltonian and the O(3) nonlinear sigma model describing

collective charge and spin excitations respectively. At a particular ratio of

the density-density to spin-spin interaction the model is integrable, and we

use the exact solutions to provide an independent derivation of the low energy

effective theory. The system is in a superfluid phase made of singlet pairs of

bosons, and we calculate the long-distance asymptotics of certain correlation

functions.

\\ ( http://arxiv.org/abs/0811.0844 , 15kb)

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arXiv:0811.0874

Date: Thu, 6 Nov 2008 06:12:25 GMT (778kb)

Title: Solitons and vortices in an evolving Bose-Einstein condensate

Authors: Shi-Jie Yang, Quan-Sheng Wu, Shiping Feng, Yu-Chuan Wen, and Yue Yu

Categories: cond-mat.supr-con

Comments: 4 pages, 4 figures

Journal-ref: Physical Review A 77,035602(2008)

\\

Spatiotemporal evolution of a confined Bose-Einstein condensate is studied by

numerically integrating the time-dependent Gross-Pitaevskii equation.

Self-interference between the successively expanding and reflecting nonlinear

matter waves results in spiral atomic density profile, which subsequently

degenerates into an embedding structure: The inner part preserves memory of the

initial states while the outer part forms a sequence of necklacelike rings. The

phase plot reveals a series of discrete concentric belts. The large gradients

between adjacent belts indicate that the ring density notches are dark

solitons. In the dynamical process, a scenario of vortex-antivortex pairs are

spontaneously created and annihilated, whereas the total vorticity keeps

invariant.

\\ ( http://arxiv.org/abs/0811.0874 , 778kb)

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arXiv:0811.1021

Date: Thu, 6 Nov 2008 20:00:31 GMT (14kb)

Title: Bose condensation of interacting gases in traps with and without optical

lattice

Authors: S. Chatterjee, A. E. Meyerovich

Categories: cond-mat.other

Comments: 9 pages, 4 figures

\\

We discuss effects of particle interaction on Bose condensation in

inhomogeneous traps with and without optical lattice. Interaction pushes normal

particles away from the condensate droplet, which is located in the center of

the trap, towards the periphery of the trap where the trapping potential is

large. In the end, the remaining normal particles are squeezed to a quasi-2D

shell around the condensate droplet thus changing the effective dimensionality

of the system. In the absence of the optical lattice the index in the

temperature dependence of the condensate density at the later stages of the

process is close to 2 with a weak dependence on the number of trapped

particles. In the presence of the lattice inside the trap this index acquires a

strong dependence on the number of particles inside the trap and gradually

falls from a 3D to a 2D value with an increase in the number of particles. This

change in index is explained by the lattice-driven spread of the condensate

droplet and the localization of the narrow band particles by the trap

potential.

\\ ( http://arxiv.org/abs/0811.1021 , 14kb)

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arXiv:0811.0925

Date: Thu, 6 Nov 2008 12:02:44 GMT (10kb)

Title: Quantum measuring processes for trapped ultracold bosonic gases

Authors: S. Anderloni, F. Benatti, R. Floreanini, A. Trombettoni

Categories: quant-ph

Comments: 11 pages, LaTeX

\\

The standard experimental techniques usually adopted in the study of the

behaviour of ultracold atoms in optical lattices involve extracting the atom

density profile from absorption images of the atomic sample after trap release.

Quantum mechanically this procedure is described by a generalized measure

(POVM); interference patterns found in absorption images suggest a generalized

measure based on fixed-phase, coherent-like states. We show that this leads to

an average atomic density which differs from the usually adopted one, obtained

as the expectation value of the atom density operator in the many-body state.

\\ ( http://arxiv.org/abs/0811.0925 , 10kb)

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and just for interest's sake:

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arXiv:0811.0237

Date: Mon, 3 Nov 2008 08:11:32 GMT (51kb)

Title: Testing bibliometric indicators by their prediction of scientists

promotions

Authors: Pablo Jensen (LET, Phys-ENS, IXXI), Jean-Baptiste Rouquier (IXXI,

LIP), Yves Croissant (LET)

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

Journal-ref: Scientometrics 3, 78 (2008) 0

DOI: 10.1007/s11192-007-2014-3

\\

We have developed a method to obtain robust quantitative bibliometric

indicators for several thousand scientists. This allows us to study the

dependence of bibliometric indicators (such as number of publications, number

of citations, Hirsch index...) on the age, position, etc. of CNRS scientists.

Our data suggests that the normalized h index (h divided by the career length)

is not constant for scientists with the same productivity but differents ages.

We also compare the predictions of several bibliometric indicators on the

promotions of about 600 CNRS researchers. Contrary to previous publications,

our study encompasses most disciplines, and shows that no single indicator is

the best predictor for all disciplines. Overall, however, the Hirsch index h

provides the least bad correlations, followed by the number of papers

published. It is important to realize however that even h is able to recover

only half of the actual promotions. The number of citations or the mean number

of citations per paper are definitely not good predictors of promotion.

\\ ( http://arxiv.org/abs/0811.0237 , 51kb)

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The replacments:

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arXiv:0801.2637

replaced with revised version Fri, 31 Oct 2008 19:28:19 GMT (40kb)

Title: Polarized polariton condensates and coupled XY models

Authors: Jonathan Keeling

Categories: cond-mat.mes-hall

Comments: 6 pages, 3 figures. Extended version

\\ ( http://arxiv.org/abs/0801.2637 , 40kb)

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arXiv:0809.3680

replaced with revised version Fri, 31 Oct 2008 11:05:05 GMT (19kb)

Title: Many-body approach to low-lying collective excitations in a BEC

approaching collapse

Authors: Anindya Biswas and Tapan Kumar Das

Categories: cond-mat.other

Comments: 8 pages, 2 figures

\\ ( http://arxiv.org/abs/0809.3680 , 19kb)

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arXiv:0807.4245

replaced with revised version Mon, 3 Nov 2008 14:39:42 GMT (78kb)

Title: Dirac-point engineering and topological phase transitions in honeycomb

optical lattices

Authors: B. Wunsch, F. Guinea, F. Sols

Categories: cond-mat.mes-hall

Comments: Published version 10 pages, 5 figures

Journal-ref: New J. Phys. 10 (2008) 103027

DOI: 10.1088/1367-2630/10/10/103027

\\ ( http://arxiv.org/abs/0807.4245 , 78kb)

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arXiv:0811.0045

replaced with revised version Tue, 4 Nov 2008 18:15:05 GMT (1171kb)

Title: Cavity QED characterization of many-body atomic states in double-well

potentials -- The role of dissipation

Authors: W. Chen and P. Meystre

Categories: quant-ph

Comments: 8 pages, 15 figures

\\ ( http://arxiv.org/abs/0811.0045 , 1171kb)

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arXiv:0803.2265

replaced with revised version Thu, 6 Nov 2008 10:59:10 GMT (974kb)

Title: Macroscopic Superpositions of Phase States with Bose-Einstein

Condensates

Authors: F. Piazza, L. Pezze', and A. Smerzi

Categories: cond-mat.other

Journal-ref: Phys. Rev. A 78, 051601 (2008)

DOI: 10.1103/PhysRevA.78.051601

\\ ( http://arxiv.org/abs/0803.2265 , 974kb)

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arXiv:0809.1814

replaced with revised version Thu, 6 Nov 2008 17:41:21 GMT (244kb)

Title: Collective oscillations of a Fermi gas in the unitarity limit:

Temperature effects and the role of pair correlations

Authors: S. Riedl, E. R. Sanchez Guajardo, C. Kohstall, A. Altmeyer, M. J.

Wright, J. Hecker Denschlag, R. Grimm, G. M. Bruun, H. Smith

Categories: cond-mat.other

Comments: 8 pages, 5 figures

Journal-ref: Phys. Rev. A 78, 053609 (2008)

DOI: 10.1103/PhysRevA.78.053609

\\ ( http://arxiv.org/abs/0809.1814 , 244kb)

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arXiv:0709.0613

replaced with revised version Thu, 6 Nov 2008 14:36:58 GMT (334kb)

Title: Complementarity and uncertainty relations for matter wave interferometry

Authors: K.-P. Marzlin, B. C. Sanders, and P. L. Knight

Categories: quant-ph

Comments: nine pages, five figures

\\ ( http://arxiv.org/abs/0709.0613 , 334kb)

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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 Mon Nov 10 2008 - 13:55:19 EST

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