# Matt's arXiv selection: week ending 9th May 2008.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
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
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
\\
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
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
\\ ( 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
\\ ( 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
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
\\ ( 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
\\ ( 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/
=========================================================================
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Received on Tue Jun 03 2008 - 08:26:51 EST

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