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

Date: Wed, 28 May 2008 22:24:59 +1000

Date: Wed, 28 May 2008 22:24:59 +1000

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

Hi everyone,

Sorry for the delays. There are 31 new preprints and 12 replacements this week.

Hopefully will be up to date again in a few days.

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arXiv:0805.0164

Date: Thu, 1 May 2008 23:45:36 GMT (240kb)

Title: Superconducting qubits

Authors: Alexandre Zagoskin and Alexandre Blais

Categories: cond-mat.supr-con cond-mat.mes-hall

Comments: Invited review article

Journal-ref: Physics in Canada, v.63, 215-227 (2007)

\\

From a physicist's standpoint, the most interesting part of quantum computing

research may well be the possibility to probe the boundary between the quantum

and the classical worlds. The more macroscopic are the structures involved, the

better. So far, the most "macroscopic" qubit prototypes that have been studied

in the laboratory are certain kinds of superconducting qubits. To get a feeling

for how macroscopic these systems can be, the states of flux qubits which are

brought in a quantum superposition corresponds to currents composed of as much

as 10^5-10^6 electrons flowing in opposite directions in a superconducting

loop. Non-superconducting qubits realized so far are all essentially

microscopic.

\\ ( http://arxiv.org/abs/0805.0164 , 240kb)

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arXiv:0805.0189

Date: Fri, 2 May 2008 08:39:29 GMT (283kb)

Title: Rabi switch of condensate wavefunctions in a multicomponent Bose gas

Authors: H.E. Nistazakis, Z. Rapti, D.J. Frantzeskakis, P.G. Kevrekidis, P.

Sodano, and A. Trombettoni

Categories: cond-mat.other

\\

Using a time-dependent linear (Rabi) coupling between the components of a

weakly interacting multicomponent Bose-Einstein condensate (BEC), we propose a

protocol for transferring the wavefunction of one component to the other. This

"Rabi switch" can be generated in a binary BEC mixture by an electromagnetic

field between the two components, typically two hyperfine states. When the

wavefunction to be transfered is - at a given time - a stationary state of the

multicomponent Hamiltonian, then, after a time delay (depending on the Rabi

frequency), it is possible to have the same wavefunction on the other

condensate. The Rabi switch can be used to transfer also moving bright

matter-wave solitons, as well as vortices and vortex lattices in

two-dimensional condensates. The efficiency of the proposed switch is shown to

be 100% when inter-species and intra-species interaction strengths are equal.

The deviations from equal interaction strengths are analyzed within a two-mode

model and the dependence of the efficiency on the interaction strengths and on

the presence of external potentials is examined in both 1D and 2D settings.

\\ ( http://arxiv.org/abs/0805.0189 , 283kb)

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arXiv:0805.0227

Date: Fri, 2 May 2008 13:11:39 GMT (71kb)

Title: One-dimensional phase transitions in a two-dimensional optical lattice

Authors: Magnus Rehn, Sara Bergkvist, Anders Rosengren, Robert Saers, Martin

Zel\'an, Emil Lundh, Anders Kastberg

Categories: cond-mat.other

Comments: 14 pages, 8 figures

\\

A phase transition for bosonic atoms in a two-dimensional anisotropic optical

lattice is considered. If the tunnelling rates in two directions are different,

the system can undergo a transition between a two-dimensional superfluid and a

one-dimensional Mott insulating array of strongly coupled tubes. The connection

to other lattice models is exploited in order to better understand the phase

transition. Critical properties are obtained using quantum Monte Carlo

calculations. These critical properties are related to correlation properties

of the bosons and a criterion for commensurate filling is established.

\\ ( http://arxiv.org/abs/0805.0227 , 71kb)

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arXiv:0805.0235

Date: Fri, 2 May 2008 14:30:54 GMT (32kb,D)

Title: Kondo polarons in a one-dimensional Fermi gas

Authors: Austen Lamacraft

Categories: cond-mat.mes-hall cond-mat.str-el

\\

We consider the motion of a spin-1/2 impurity in a one-dimensional gas of

spin-1/2 fermions. For antiferromagnetic interaction between the impurity and

the fermions, the low temperature behavior of the system is governed by the

two-channel Kondo effect, leading to the impurity becoming completely opaque to

the spin excitations of the gas. As well as the known spectral signatures of

the two-channel Kondo effect, we find that the low temperature mobility of the

resulting `Kondo polaron' takes the universal form $\mu\to \frac{3\hbar

v_F^2}{2\pi k_B^2T^2}$, in sharp contrast to the spinless case where

$\mu\propto T^{-4}$.

\\ ( http://arxiv.org/abs/0805.0235 , 32kb)

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arXiv:0805.0255

Date: Fri, 2 May 2008 16:34:50 GMT (146kb)

Title: Strong-Coupling Phases of Frustrated Bosons on a 2-leg Ladder with Ring

Exchange

Authors: D. N. Sheng, Olexei I. Motrunich, Simon Trebst, Emanuel Gull, Matthew

P. A. Fisher

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

Comments: 22 pages, 15 figures

\\

Developing a theoretical framework to access quantum phases of itinerant

bosons or fermions in two dimensions (2D) that exhibit singular structure along

surfaces in momentum space but have no quasi-particle description remains as a

central challenge in the field of strongly correlated physics. In this paper we

propose that distinctive signatures of such 2D strongly correlated phases will

be manifest in quasi-one-dimensional "N-leg ladder" systems. Characteristic of

each parent 2D quantum liquid would be a precise pattern of 1D gapless modes on

the N-leg ladder. These signatures could be potentially exploited to approach

the 2D phases from controlled numerical and analytical studies in quasi-1D. As

a first step we explore itinerant boson models with a frustrating ring exchange

interaction on the 2-leg ladder, searching for signatures of the recently

proposed two-dimensional d-wave correlated Bose liquid (DBL) phase. A

combination of exact diagonalization, density matrix renormalization group,

variational Monte Carlo, and bosonization analysis of a quasi-1D gauge theory,

all provide compelling evidence for the existence of a new strong-coupling

phase of bosons on the 2-leg ladder which can be understood as a descendant of

the two-dimensional DBL. We suggest several generalizations to quantum spin and

electron Hamiltonians on ladders which could likewise reveal fingerprints of

such 2D non-Fermi liquid phases.

\\ ( http://arxiv.org/abs/0805.0255 , 146kb)

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arXiv:0805.0260

Date: Fri, 2 May 2008 16:42:52 GMT (615kb)

Title: Directly determining the relative phase of two coherent solitary waves

in attractive Bose-Einstein condensates

Authors: Weibin Li

Categories: cond-mat.other

Comments: 5 pages, 4 figures

\\

We study the dynamic structure factor of two coherent bright solitary waves

in attractive Bose- Einstein condensates confined in a harmonic trap. We

demonstrate that the wave function of the two solitary waves with a fixed

relative phase shows interference in momentum space. The fringes are shifted

depending on the values of the phase. This momentum interference can be

extracted from the dynamic structure factor of the system using stimulated

two-photon Bragg scattering. Thus our method provides a way to measure the

relative phase directly.

\\ ( http://arxiv.org/abs/0805.0260 , 615kb)

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arXiv:0805.0295

Date: Fri, 2 May 2008 19:42:07 GMT (57kb)

Title: Bragg spectroscopy of a strongly interacting 85Rb Bose-Einstein

condensate

Authors: S. B. Papp, J. M. Pino, R. J. Wild, S. Ronen, C. E. Wieman, D. S. Jin,

and E. A. Cornell

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\

We report on measurements of the excitation spectrum of a strongly

interacting Bose-Einstein condensate (BEC). A magnetic-field Feshbach resonance

is used to tune atom-atom interactions in the condensate and to reach a regime

where quantum depletion and beyond mean-field corrections to the condensate

chemical potential are significant. We use two-photon Bragg spectroscopy to

probe the condensate excitation spectrum; our results demonstrate the onset of

beyond mean-field effects in a gaseous BEC.

\\ ( http://arxiv.org/abs/0805.0295 , 57kb)

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arXiv:0805.0023 (*cross-listing*)

Date: Wed, 30 Apr 2008 23:23:30 GMT (487kb)

Title: Two-Component Nonlinear Schrodinger Models with a Double-Well Potential

Authors: C. Wang, P. G. Kevrekidis, N. Whitaker, B. A. Malomed

Categories: nlin.PS cond-mat.other

Comments: 17 pages, 12 figures, Physica D, in press

\\

We introduce a model motivated by studies of Bose-Einstein condensates (BECs)

trapped in double-well potentials. We assume that a mixture of two hyperfine

states of the same atomic species is loaded in such a trap.The analysis is

focused on symmetry-breaking bifurcations in the system, starting at the linear

limit and gradually increasing the nonlinearity. Depending on values of the

chemical potentials of the two species, we find numerous states, as well as

symmetry-breaking bifurcations, in addition to those known in the

single-component setting. These branches, which include all relevant stationary

solutions of the problem, are predicted analytically by means of a two-mode

approximation, and confirmed numerically. For unstable branches, outcomes of

the instability development are explored in direct simulations.

\\ ( http://arxiv.org/abs/0805.0023 , 487kb)

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arXiv:0805.0247

Date: Fri, 2 May 2008 15:39:23 GMT (353kb)

Title: 1-D Mott insulator transition of a Bose-Einstein condensate

Authors: R. E. Sapiro, R. Zhang, G. Raithel

Categories: physics.atom-ph

Comments: 5 pages, 5 figures

\\

The superfluid to one-dimensional Mott-insulator transition of a 87Rb

Bose-Einstein condensate is demonstrated. In the experiment, we apply a

one-dimensional optical lattice, formed by two laser beams with a wavelength of

852 nm, to a three dimensional BEC in a shallow trap. We use Kapitza-Dirac

scattering to determine the depth of the optical lattice without knowledge of

its exact geometry. We further study the dynamics of the transition as well as

steady-state phase behavior specific to the one-dimensional case.

\\ ( http://arxiv.org/abs/0805.0247 , 353kb)

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arXiv:0805.0404

Date: Sun, 4 May 2008 11:29:38 GMT (155kb)

Title: Controlled generation of coherent matter-currents using a periodic

driving field

Authors: C.E. Creffield and F. Sols

Categories: cond-mat.other

Comments: 4.1 pages, 4 eps figures

\\

We study the effect of a strong, oscillating driving field on the dynamics of

ultracold bosons held in an optical lattice. Modeling the system as a

Bose-Hubbard model, we show how the driving field can be used to produce and

maintain a coherent atomic current by controlling the phase of the intersite

tunneling processes. We investigate both the stroboscopic and time-averaged

behavior using Floquet theory, and demonstrate that this procedure provides a

stable and precise method of controlling coherent quantum systems.

\\ ( http://arxiv.org/abs/0805.0404 , 155kb)

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arXiv:0805.0457

Date: Mon, 5 May 2008 05:03:21 GMT (753kb)

Title: Repulsive shield between polar molecules

Authors: A. V. Gorshkov, P. Rabl, G. Pupillo, A. Micheli, P. Zoller, M. D.

Lukin, H. P. B\"uchler

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

Comments: 4 pages, 3 figures

\\

We propose and analyze a technique that allows to suppress inelastic

collisions and simultaneously enhance elastic interactions between cold polar

molecules. The main idea is to cancel the leading dipole-dipole interaction

with a suitable combination of static electric and microwave fields in such a

way that the remaining van-der-Waals-type potential forms a three-dimensional

repulsive shield. We analyze the elastic and inelastic scattering cross

sections relevant for evaporative cooling of polar molecules and discuss the

prospect for the creation of crystalline structures.

\\ ( http://arxiv.org/abs/0805.0457 , 753kb)

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arXiv:0805.0487

Date: Mon, 5 May 2008 09:04:40 GMT (412kb)

Title: Localization of the relative phase via measurements

Authors: G. S. Paraoanu

Categories: cond-mat.stat-mech

Comments: 8 pages, 1 figure

\\

When two independently-prepared Bose-Einstein condensates are released from

their corresponding traps, the absorbtion image of the overlapping clouds

presents an interference pattern. Here we analyze a model introduced by

Javanainen and Yoo (J. Javanainen and S. M. Yoo, Phys. Rev. Lett. 76, 161

(1996)), who considered two atomic condensates described by plane waves

propagating in opposite directions. We present an analytical argument for the

measurement-induced breaking of the relative phase symmetry in this system,

demonstrating how the phase gets localized after a large enough number of

detection events.

\\ ( http://arxiv.org/abs/0805.0487 , 412kb)

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arXiv:0805.0488

Date: Mon, 5 May 2008 09:06:04 GMT (913kb,D)

Title: Physical replicas and the Bose-glass in cold atomic gases

Authors: S. Morrison, A. Kantian, A. J. Daley, H.G. Katzgraber, M. Lewenstein,

H. P. B\"uchler, and P. Zoller

Categories: cond-mat.other cond-mat.dis-nn

Comments: 16 pages, 6 figures

\\

We study cold atomic gases in a disorder potential and analyze the

correlations between different systems subjected to the same disorder

landscape. Such independent copies with the same disorder landscape are known

as replicas. While in general these are not accessible experimentally in

condensed matter systems, they can be realized using standard tools for

controlling cold atomic gases in an optical lattice. Of special interest is the

overlap function which represents a natural order parameter for disordered

systems and is a correlation function between the atoms of two independent

replicas with the same disorder. We demonstrate an efficient measurement scheme

for the determination of this disorder-induced correlation function. As an

application, we focus on the disordered Bose-Hubbard model and determine the

overlap function within perturbation theory and a numerical analysis. We find

that the measurement of the overlap function allows for the identification of

the Bose-glass phase in certain parameter regimes.

\\ ( http://arxiv.org/abs/0805.0488 , 913kb)

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arXiv:0805.0531

Date: Mon, 5 May 2008 13:43:23 GMT (249kb)

Title: Differences between mean-field dynamics and N-particle quantum dynamics

as a signature of entanglement

Authors: Christoph Weiss (LKB - Lhomond), Niklas Teichmann (UMSIHP)

Categories: cond-mat.other

Comments: four pages, five figures

Journal-ref: Physical Review Letters 100 (2008) 140408

DOI: 10.1103/PhysRevLett.100.140408

\\

A Bose-Einstein condensate in a tilted double-well potential under the

influence of time-periodic potential differences is investigated in the regime

where the mean-field (Gross-Pitaevskii) dynamics become chaotic. For some

parameters near stable regions, even averaging over several condensate

oscillations does not remove the differences between mean-field and N-particle

results. While introducing decoherence via piecewise deterministic processes

reduces those differences, they are due to the emergence of mesoscopic

entangled states in the chaotic regime.

\\ ( http://arxiv.org/abs/0805.0531 , 249kb)

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arXiv:0805.0482

Date: Mon, 5 May 2008 11:07:22 GMT (23kb)

Title: Atomic spin squeezing in an optical cavity

Authors: Anne E. B. Nielsen and Klaus Molmer

Categories: quant-ph

Comments: 8 pages, 2 figures

\\

We consider squeezing of one component of the collective spin vector of an

atomic ensemble inside an optical cavity. The atoms interact with a cavity

mode, and the squeezing is obtained by probing the state of the light field

that is transmitted through the cavity. Starting from the stochastic master

equation, we derive the time evolution of the state of the atoms and the cavity

field, and we compute expectation values and variances of the atomic spin

components and the quadratures of the cavity mode. The performance of the setup

is compared to spin squeezing of atoms by probing of a light field transmitted

only once through the sample.

\\ ( http://arxiv.org/abs/0805.0482 , 23kb)

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arXiv:0805.0528

Date: Mon, 5 May 2008 13:34:16 GMT (462kb)

Title: The conversion of phase to amplitude fluctuations of a light beam by an

optical cavity

Authors: Alessandro S. Villar

Categories: quant-ph

\\

Very low intensity and phase fluctuations are present in a bright light field

such as a laser beam. These subtle quantum fluctuations may be used to encode

quantum information. Although intensity is easily measured with common

photodetectors, accessing the phase information requires interference

experiments. We introduce one such technique, the rotation of the noise ellipse

of light, which employs an optical cavity to achieve the conversion of phase to

intensity fluctuations. We describe the quantum noise of light and how it can

be manipulated by employing an optical resonance technique and compare it to

similar techniques, such as Pound-Drever-Hall laser stabilization and homodyne

detection.

\\ ( http://arxiv.org/abs/0805.0528 , 462kb)

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arXiv:0805.0477

Date: Mon, 5 May 2008 07:14:34 GMT (101kb)

Title: Probing a Bose-Einstein Condensate with an Atom Laser

Authors: D. D\"oring, N. P. Robins, C. Figl, and J. D. Close

Categories: physics.atom-ph

Comments: 4 pages, 3 figures

\\

We use a pulsed atom laser derived from a Bose-Einstein condensate to probe a

second target condensate. The target condensate scatters the incident atom

laser pulse. From the spatial distribution of scattered atoms, we measure the

s-wave scattering length that, in low energy collisions, describes the

interaction between the |F=1,m_F=-1> and |F=2,m_F=0> hyperfine ground states in

87Rb.

\\ ( http://arxiv.org/abs/0805.0477 , 101kb)

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arXiv:0805.0623

Date: Tue, 6 May 2008 02:44:18 GMT (574kb,D)

Title: Realization of a strongly interacting Bose-Fermi mixture from a

two-component Fermi gas

Authors: Yong-il Shin, Andr\'e Schirotzek, Christian H. Schunck, Wolfgang

Ketterle

Categories: cond-mat.stat-mech

Comments: 5 pages, 5 figures

\\

We show the emergence of a strongly interacting Bose-Fermi mixture from a

two-component Fermi mixture with population imbalance. By analyzing in situ

density profiles of $^6$Li atoms in the BCS-BEC crossover regime we identify a

critical interaction strength, beyond which all minority atoms pair up with

majority atoms, and form a Bose condensate. This is the regime where the system

can be effectively described as a boson-fermion mixture. We determine the

dimer-fermion and dimer-dimer scattering lengths and beyond-mean-field

contributions. Our study realizes a Gedanken experiment of bosons immersed in a

Fermi sea of one of their constituents, revealing the composite nature of the

bosons.

\\ ( http://arxiv.org/abs/0805.0623 , 574kb)

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arXiv:0805.0738

Date: Tue, 6 May 2008 08:48:58 GMT (1316kb)

Title: Composite fermionization of 1-D Bose-Bose mixtures

Authors: Sascha Z\"ollner, Hans-Dieter Meyer, Peter Schmelcher

Categories: cond-mat.other

Comments: 9 pages, 9 figures

\\

We study the ground states of one-dimensional Bose-Bose mixtures under

harmonic confinement. As we vary the inter-species coupling strength up to the

limit of infinite repulsion, we observe a generalized, composite-fermionization

crossover. The initially coexisting phases demix as a whole (for weak

intra-species interactions) and separate on an atomic level (for strong

intra-species repulsion). By symmetry, the two components end up with strongly

overlapping profiles, albeit sensitive to symmetry-breaking perturbations.

Different pathways emerge in case the two components have different atom

numbers, different intra-species interactions, or different masses and/or trap

frequencies.

\\ ( http://arxiv.org/abs/0805.0738 , 1316kb)

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arXiv:0805.0761

Date: Tue, 6 May 2008 17:28:35 GMT (776kb)

Title: Nonlinear Waves in Bose-Einstein Condensates: Physical Relevance and

Mathematical Techniques

Authors: R. Carretero-Gonzalez, D.J. Frantzeskakis, and P.G. Kevrekidis

Categories: cond-mat.other

Comments: 69 pages, 10 figures, to appear in Nonlinearity, 2008

\\

The aim of the present review is to introduce the reader to some of the

physical notions and of the mathematical methods that are relevant to the study

of nonlinear waves in Bose-Einstein Condensates (BECs). Upon introducing the

general framework, we discuss the prototypical models that are relevant to this

setting for different dimensions and different potentials confining the atoms.

We analyze some of the model properties and explore their typical wave

solutions (plane wave solutions, bright, dark, gap solitons, as well as

vortices). We then offer a collection of mathematical methods that can be used

to understand the existence, stability and dynamics of nonlinear waves in such

BECs, either directly or starting from different types of limits (e.g., the

linear or the nonlinear limit, or the discrete limit of the corresponding

equation). Finally, we consider some special topics involving more recent

developments, and experimental setups in which there is still considerable need

for developing mathematical as well as computational tools.

\\ ( http://arxiv.org/abs/0805.0761 , 776kb)

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arXiv:0805.0655

Date: Tue, 6 May 2008 07:14:10 GMT (764kb)

Title: Photon-Mediated Interaction between Two Distant Atoms

Authors: Stefan Rist, J\"urgen Eschner, Markus Hennrich and Giovanna Morigi

Categories: quant-ph

Comments: 18 pages, 15 figures

\\

We study the photonic interactions between two distant atoms which are

coupled by an optical element (a lens or an optical fiber) focussing part of

their emitted radiation onto each other. Two regimes are distinguished

depending on the ratio between the radiative lifetime of the atomic excited

state and the propagation time of a photon between the two atoms. In the two

regimes, well below saturation the dynamics exhibit either typical features of

a bad resonator, where the atoms act as the mirrors, or typical characteristics

of dipole-dipole interaction. We study the coherence properties of the emitted

light and show that it carries signatures of the multiple scattering processes

between the atoms. The model predictions are compared with the experimental

results in J. Eschner {\it et al.}, Nature {\bf 413}, 495 (2001).

\\ ( http://arxiv.org/abs/0805.0655 , 764kb)

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arXiv:0805.0758

Date: Tue, 6 May 2008 17:18:43 GMT (669kb)

Title: Observation of Rydberg blockade between two atoms

Authors: E. Urban, T. A. Johnson, T. Henage, L. Isenhower, D. D. Yavuz, T. G.

Walker, and M. Saffman

Categories: quant-ph

Comments: 4 figures

\\

We demonstrate experimentally that a single Rb atom excited to the

$79d_{5/2}$ level blocks the subsequent excitation of a second atom located

more than $10 \mu\rm m$ away. The observed probability of double excitation of

$\sim 30%$ is consistent with a theoretical model based on calculations of the

long range dipole-dipole interaction between atoms.

\\ ( http://arxiv.org/abs/0805.0758 , 669kb)

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arXiv:0805.0765

Date: Tue, 6 May 2008 19:11:37 GMT (760kb)

Title: Controlled insertion and retrieval of atoms coupled to a high-finesse

optical resonator

Authors: Mkrtych Khudaverdyan, Wolfgang Alt, Igor Dotsenko, Tobias Kampschulte,

Karim Lenhard, Arno Rauschenbeutel, Sebastian Reick, Karsten Sch\"orner,

Artur Widera, and Dieter Meschede

Categories: quant-ph

\\

We experimentally investigate the interaction between one and two atoms and

the field of a high-finesse optical resonator. Laser-cooled caesium atoms are

transported into the cavity using an optical dipole trap. We monitor the

interaction dynamics of a single atom strongly coupled to the resonator mode

for several hundred milliseconds by observing cavity transmission. Moreover, we

investigate the position and atom-number dependent coupling strength by

shuttling one or two atoms through the cavity mode. We demonstrate an

alternative method, which suppresses heating effects, to analyze the atom-field

interaction by retrieving the atom from the cavity and by measuring its final

state.

\\ ( http://arxiv.org/abs/0805.0765 , 760kb)

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arXiv:0805.0798

Date: Wed, 7 May 2008 16:45:55 GMT (549kb)

Title: Exploring local quantum many-body relaxation by atoms in optical

superlattices

Authors: M. Cramer, A. Flesch, I.P. McCulloch, U. Schollwoeck, J. Eisert

Categories: cond-mat.stat-mech

Comments: 5 pages, 3 figures

\\

We establish a setting - atoms in optical superlattices with period 2 - in

which one can experimentally probe signatures of the process of local

relaxation and apparent thermalization in non-equilibrium dynamics without the

need of addressing single sites. This opens up a way to explore the convergence

of subsystems to maximum entropy states in quenched quantum many-body systems

with present technology. Remarkably, the emergence of thermal states does not

follow from a coupling to an environment, but is a result of the complex

non-equilibrium dynamics in closed systems. We explore ways of measuring the

relevant signatures of thermalization in this analogue quantum simulation of a

relaxation process, exploiting the possibilities offered by optical

superlattices.

\\ ( http://arxiv.org/abs/0805.0798 , 549kb)

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arXiv:0805.0847

Date: Wed, 7 May 2008 07:41:47 GMT (840kb)

Title: Properties of rotating two-component Bose-Einstein Condensates

Authors: I. Corro, R.G. Scott and A.M. Martin

Categories: cond-mat.other

Comments: 5 pages, 3 figures

\\

We derive equations of motion for rotating two-component Bose-Einstein

Condensates, finding multiple solutions. Stability analysis of these solutions

and comparison with Truncated Wigner simulations enables us to identify the

regimes for which giant multiply quantized vortices and interlocking vortex

lattices will occur. In addition, our analysis predicts novel center of mass

oscillations.

\\ ( http://arxiv.org/abs/0805.0847 , 840kb)

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arXiv:0805.1025

Date: Wed, 7 May 2008 17:07:51 GMT (519kb)

Title: Winding up by a quench: Insulator to superfluid phase transition in a

ring of BECs

Authors: J. Dziarmaga, J. Meisner, and W.H. Zurek

Categories: cond-mat.stat-mech

Comments: 4 pages, 3 figures

\\

We study phase transition from the Mott insulator to superfluid in a periodic

optical lattice. Kibble-Zurek mechanism predicts buildup of winding number

through random walk of BEC phases, with the step size scaling as a the third

root of transition rate. We confirm this and demonstrate that this scaling

accounts for the net winding number after the transition.

\\ ( http://arxiv.org/abs/0805.1025 , 519kb)

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arXiv:0805.1036

Date: Wed, 7 May 2008 18:19:32 GMT (683kb)

Title: Observation of Anomalous Spin Segregation in a Trapped Fermi Gas

Authors: X. Du, L. Luo, B. Clancy, and J. E. Thomas

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\

We report the observation of spin segregation, i.e., separation of spin

density profiles, in a trapped ultracold Fermi gas of $^6$Li with a

magnetically tunable scattering length close to zero. The roles of the spin

components are inverted when the sign of the scattering length is reversed. The

observed density profiles are in qualitative agreement with the spin-wave

theory applied previously to explain spin segregation in a Bose gas, but

disagree in amplitude by two orders of magnitude. The observed atomic density

profiles are far from equilibrium, yet they persist for $\simeq$ 5 seconds in a

trap with an axial frequency of $\simeq$ 150 Hz. We attribute this long

lifetime to Fermi statistics: The scattering amplitude is nonzero only for

atoms in opposite states, and vanishes for atoms in the same state. By

measuring the magnetic field at which spin segregation ceases, we precisely

determine the zero crossing in the scattering length of $^6$Li as $527.5\pm0.2$

G.

\\ ( http://arxiv.org/abs/0805.1036 , 683kb)

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arXiv:0805.1048

Date: Wed, 7 May 2008 19:20:11 GMT (9kb)

Title: Exactly solvable models for triatomic-molecular Bose-Einstein

Condensates

Authors: G. Santos, A. Foerster, I. Roditi, Z. V. T. Santos, A. P. Tonel

Categories: cond-mat.other

Comments: 11 pages

\\

We construct a family of triatomic models for heteronuclear and homonuclear

molecular Bose-Einstein condensates. We show that these new generalized models

are exactly solvable through the algebraic Bethe ansatz method and derive their

corresponding Bethe ansatz equations and energies.

\\ ( http://arxiv.org/abs/0805.1048 , 9kb)

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arXiv:0805.0816

Date: Wed, 7 May 2008 00:26:44 GMT (9kb)

Title: Laguerre-Gaussian Modes and the Wigner Transform

Authors: Michael VanValkenburgh

Categories: quant-ph

\\

Recent developments in laser physics have called renewed attention to orbital

angular momentum modes for the paraxial wave equation. In this paper we will

consider the corresponding Laguerre-Gaussian modes for the two-dimensional

harmonic oscillator, which appear in the transversal plane at the laser beam's

waist. We will see how they arise as Wigner transforms of Hermite-Gaussian

modes, and then we will proceed to find their own Wigner transforms. The main

observation is that the Wigner transform intertwines the creation and

annihilation operators for the two classes of modes. Our methods provide an

alternative to other recent methods of Gase and Simon--Agarwal, and indeed give

a more general result.

\\ ( http://arxiv.org/abs/0805.0816 , 9kb)

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\\

arXiv:0805.1081

Date: Thu, 8 May 2008 00:53:32 GMT (389kb)

Title: Mesoscopic pendulum and giant-persistent current on a superconducting

ring

Authors: Yanzhang He, Chengguang Bao

Categories: cond-mat.other

Comments: 4 pages, 3 figures

\\

A device as a controllable quantum pendulum based on a mesoscopic

superconducting ring is proposed. The ring is threaded by a magnetic flux. A

potential is set upon a segment of the ring to localize the electron initially.

Then a sudden cancellation of both the potential and the flux may cause an

exact periodic motion of the electron, which is in nature different from the

well known Aharonov-Bohm (A-B) oscillation. The period of oscillation is

controllable. The associated persistent current can be tuned more than two

orders larger than the usual A-B current. Related theory and numerical results

are presented.

\\ ( http://arxiv.org/abs/0805.1081 , 389kb)

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\\

arXiv:0805.1139

Date: Thu, 8 May 2008 11:12:13 GMT (762kb)

Title: Absolute absorption on the rubidium D lines: comparison between theory

and experiment

Authors: Paul Siddons, Charles S. Adams, Chang Ge and Ifan G. Hughes

Categories: physics.atom-ph

Comments: 18 pages, 8 figures, submitted to Journal of Physics B

\\

We study the Doppler-broadened absorption of a weak monochromatic probe beam

in a thermal rubidium vapour cell on the D lines. A detailed model of the

susceptibility is developed which takes into account the absolute linestrengths

of the allowed electric dipole transitions and the motion of the atoms parallel

to the probe beam. All transitions from both hyperfine levels of the ground

term of both isotopes are incorporated. The absorption and refractive index as

a function of frequency are expressed in terms of the complementary error

function. The absolute absorption profiles are compared with experiment, and

are found to be in excellent agreement provided a sufficiently weak probe beam

with an intensity under one thousandth of the saturation intensity is used. The

importance of hyperfine pumping for open transitions is discussed in the

context of achieving the weak-probe limit. Theory and experiment show excellent

agreement, with an rms error better than 0.2% for the D2 line at 16.5 degrees

C.

\\ ( http://arxiv.org/abs/0805.1139 , 762kb)

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The replacements:

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\\

arXiv:0711.2325

replaced with revised version Wed, 7 May 2008 02:27:41 GMT (654kb,D)

Title: Collective spin systems in dispersive optical cavity QED: Quantum phase

transitions and entanglement

Authors: S. Morrison, A.S. Parkins

Categories: quant-ph cond-mat.other

Comments: 19 pages, 18 figures, shortened version

Journal-ref: Phys. Rev. A 77, 043810 (2008)

DOI: 10.1103/PhysRevA.77.043810

\\ ( http://arxiv.org/abs/0711.2325 , 654kb)

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\\

arXiv:cond-mat/0703087

replaced with revised version Thu, 1 May 2008 23:42:01 GMT (337kb)

Title: p-wave Feshbach molecules

Authors: J. P. Gaebler, J. T. Stewart, J. L. Bohn, D. S. Jin

Categories: cond-mat.other

Journal-ref: Phys. Rev. Lett. 98, 200403 (2007)

DOI: 10.1103/PhysRevLett.98.200403

\\ ( http://arxiv.org/abs/cond-mat/0703087 , 337kb)

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\\

arXiv:0802.4097

replaced with revised version Thu, 1 May 2008 22:45:59 GMT (719kb)

Title: Manifestations of the Roton Mode in Dipolar Bose-Einstein Condensates

Authors: Ryan M. Wilson, Shai Ronen, Han Pu and John L. Bohn

Categories: cond-mat.other

Comments: 4 pages, 2 column format, 3 figures, submitted to PRL

\\ ( http://arxiv.org/abs/0802.4097 , 719kb)

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\\

arXiv:0712.3866

replaced with revised version Mon, 5 May 2008 07:30:02 GMT (170kb)

Title: Resonant tunneling of Bose-Einstein condensates in optical lattices

Authors: Alessandro Zenesini, Carlo Sias, Hans Lignier, Yeshpal Singh,

Donatella Ciampini, Oliver Morsch, Riccardo Mannella, Ennio Arimondo, Andrea

Tomadin, and Sandro Wimberger

Categories: cond-mat.other

Comments: New J. Phys., in press

\\ ( http://arxiv.org/abs/0712.3866 , 170kb)

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\\

arXiv:0804.4003

replaced with revised version Fri, 2 May 2008 20:46:47 GMT (26kb)

Title: Adiabatic nonlinear probes of one-dimensional Bose gases

Authors: C. De Grandi, R. A. Barankov, A. Polkovnikov

Categories: cond-mat.other

Comments: 4+ pages, 4 figures, corrected references, added acknowledgements

\\ ( http://arxiv.org/abs/0804.4003 , 26kb)

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\\

arXiv:0802.0833

replaced with revised version Mon, 5 May 2008 14:31:59 GMT (81kb)

Title: The inherent fluctuations of the pulsed atom laser produced in the F=2

manifold

Authors: Lin Xia, Fan Yang, Xu Xu, Xiaoji Zhou and Xuzong Chen

Categories: physics.atom-ph

Comments: 5 pages, 6 figures

\\ ( http://arxiv.org/abs/0802.0833 , 81kb)

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\\

arXiv:0710.5318

replaced with revised version Tue, 6 May 2008 03:41:24 GMT (17kb)

Title: Phase diagram of a Bose gas near a wide Feshbach resonance

Authors: Lan Yin

Categories: cond-mat.other cond-mat.stat-mech cond-mat.str-el cond-mat.supr-con

Comments: 5 pages, 4 figures

Journal-ref: Phys. Rev. A 77, 043630 (2008)

\\ ( http://arxiv.org/abs/0710.5318 , 17kb)

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\\

arXiv:0801.0932

replaced with revised version Tue, 6 May 2008 07:29:45 GMT (377kb)

Title: Optimum spin-squeezing in Bose-Einstein condensates with particle losses

Authors: Yun Li (LKB - Lhomond, ECNU), Yvan Castin (LKB - Lhomond), Alice

Sinatra (LKB - Lhomond)

Categories: quant-ph

Comments: 4 pages

\\ ( http://arxiv.org/abs/0801.0932 , 377kb)

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\\

arXiv:cond-mat/0612261

replaced with revised version Wed, 7 May 2008 11:12:15 GMT (303kb)

Title: Controllable diffusion of cold atoms in a harmonically driven and tilted

optical lattice: Decoherence by spontaneous emission

Authors: Navinder Singh

Categories: cond-mat.stat-mech

Comments: 16 pages, 7 figures, revised version

\\ ( http://arxiv.org/abs/cond-mat/0612261 , 303kb)

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\\

arXiv:0704.3868

replaced with revised version Thu, 8 May 2008 05:32:02 GMT (27kb)

Title: An effective many-body theory for strongly interacting polar molecules

Authors: Daw-Wei Wang

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

Comments: Same as published version (11 pages, 2 figure)

Journal-ref: New J. Phys. 10 (2008) 053005

DOI: 10.1088/1367-2630/10/5/053005

\\ ( http://arxiv.org/abs/0704.3868 , 27kb)

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\\

arXiv:0804.4631

replaced with revised version Thu, 8 May 2008 16:40:22 GMT (37kb)

Title: Andreev reflection in bosonic condensates

Authors: I. Zapata and F. Sols

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

Comments: 4 pages, 3 figures. Text revised

\\ ( http://arxiv.org/abs/0804.4631 , 37kb)

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\\

arXiv:0707.3834

replaced with revised version Thu, 8 May 2008 16:12:57 GMT (411kb)

Title: Spin squeezing in optical lattice clocks via lattice-based QND

measurements

Authors: D. Meiser, Jun Ye, and M. J. Holland

Categories: quant-ph physics.atom-ph

Comments: Substantially expanded version

\\ ( http://arxiv.org/abs/0707.3834 , 411kb)

-----------------------------------------------------------------------------

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 Tue Jun 03 2008 - 08:26:51 EST

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