Matt's arXiv selection: week ending 7th September 2007. (fwd) from Matthew Davis on 2007-10-06 (Matt's arXiv selection)

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Sat, 6 Oct 2007 22:07:09 +1000 (EST)

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

Hi everyone,

All sorts of circumstances over the past four weeks that I won't go into have
gotten in the way of this email, but hopefully a more normal service will
resume in short order. I haven't stopped just yet!

In the week that this email covers, there are 26 new preprints and 10
replacements.

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arXiv:0708.4304
Date: Fri, 31 Aug 2007 09:31:00 GMT (463kb,D)

Title: Control of atomic currents using a quantum stirring device
Authors: Moritz Hiller, Tsampikos Kottos, Doron Cohen
Categories: cond-mat.mes-hall cond-mat.other
Comments: 5 pages, 4 figures
\\
We propose a BEC stirring device which can be regarded as the incorporation
of a quantum pump into a closed circuit: it produces a DC circulating current
in response to a cyclic adiabatic change of two control parameters of an
optical trap. We demonstrate the feasibility of this concept and point out that
such device can be utilized in order to probe the interatomic interactions.
\\ ( http://arxiv.org/abs/0708.4304 , 463kb)
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\\
arXiv:0709.0012
Date: Fri, 31 Aug 2007 20:53:42 GMT (257kb)

Title: Observation of persistent flow of a Bose-Einstein condensate in a
   toroidal trap
Authors: C. Ryu, M. F. Andersen, P. Clade, Vasant Natarajan, K. Helmerson, W.
   D. Phillips
Categories: cond-mat.other cond-mat.supr-con
Comments: 1 file, 5 figures
\\
   We have observed the persistent flow of Bose-condensed atoms in a toroidal
trap. The flow persists without decay for up to 10 s, limited only by
experimental factors such as drift and trap lifetime. The quantized rotation
was initiated by transferring one unit, $\hbar$, of the orbital angular
momentum from Laguerre-Gaussian photons to each atom. Stable flow was only
possible when the trap was multiply-connected, and was observed with a BEC
fraction as small as 15%. We also created flow with two units of angular
momentum, and observed its splitting into two singly-charged vortices when the
trap geometry was changed from multiply- to simply-connected.
\\ ( http://arxiv.org/abs/0709.0012 , 257kb)
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\\
arXiv:0709.0149
Date: Mon, 3 Sep 2007 03:56:02 GMT (10kb)

Title: Blackbody radiation shift in a 43Ca+ ion optical frequency standard
Authors: Bindiya Arora, M. S. Safronova, and Charles W. Clark
Categories: quant-ph
Comments: 4 pages
\\
Motivated by the prospect of an optical frequency standard based on 43Ca+, we
calculate the blackbody radiation (BBR) shift of the 4s_1/2-3d_5/2 clock
transition, which is a major component of the uncertainty budget. The
calculations are based on the relativistic all-order single-double method where
all single and double excitations of the Dirac-Fock wave function are included
to all orders of perturbation theory. Additional calculations are conducted for
the dominant contributions in order to evaluate some omitted high-order
corrections and estimate the uncertainties of the final results. The BBR shift
obtained for this transition is 0.38(1) Hz. The tensor polarizability of the
3d_5/2 level is also calculated and its uncertainty is evaluated as well. Our
results are compared with other calculations.
\\ ( http://arxiv.org/abs/0709.0149 , 10kb)
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\\
arXiv:0709.0212
Date: Mon, 3 Sep 2007 12:32:54 GMT (10kb)

Title: Generation of non-critically squeezed light via spontaneous rotational
symmetry breaking
Authors: Carlos Navarrete-Benlloch, Eugenio Roldan, and German J. de Valcarcel
Categories: quant-ph
Comments: 4 pages, no figures
\\
We theoretically address the generation of squeezed light through the
spontaneous breaking of rotational invariance that occurs in a two-mode
degenerate optical parametric oscillator (DOPO) pumped above threshold. In
particular, we show that a DOPO with spherical mirrors in which the signal and
idler fields, which are degenerate in frequency and polarization, correspond to
first order Gauss-Laguerre modes, produces a perfectly squeezed vacuum, within
the linearized theory, at any pumping level above threshold. Hence the
phenomenon is non-critical.
\\ ( http://arxiv.org/abs/0709.0212 , 10kb)
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\\
arXiv:0708.4056 (*cross-listing*)
Date: Thu, 30 Aug 2007 02:34:24 GMT (86kb)

Title: Renormalization group analysis of resonantly interacting anyons
Authors: Yusuke Nishida
Categories: hep-th cond-mat.other nucl-th quant-ph
Comments: 5 pages, 5 figures
Report-no: INT-PUB 07-20
\\
We formulate a field theory for resonantly interacting anyons, which enables
us to perform a perturbative calculation near the fermionic limit. We derive
renormalization group equations for three-body and four-body couplings at
one-loop order. In addition to two fixed points, we find a limit cycle behavior
in the four-body coupling, which implies an infinite set of bound states in the
four anyon system.
\\ ( http://arxiv.org/abs/0708.4056 , 86kb)
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arXiv:0709.0014
Date: Fri, 31 Aug 2007 21:19:22 GMT (10kb)

Title: Accurate determination of electric-dipole matrix elements in K and Rb
from Stark shift measurements
Authors: Bindiya Arora, M. S. Safronova, and Charles W. Clark
Categories: physics.atom-ph
Comments: 5 pages
\\
Stark shifts of potassium and rubidium D1 lines have been measured with high
precision by Miller et al [1]. In this work, we combine these measurements with
our all-order calculations to determine the values of the electric-dipole
matrix elements for the 4p_j-3d_j' transitions in K and for the 5p_j-4d_j'
transitions in Rb to high precision. The 4p_1/2-3d_3/2 and 5p_1/2-4d_3/2
transitions contribute on the order of 90% to the respective polarizabilities
of the np_1/2 states in K and Rb, and the remaining 10% can be accurately
calculated using the relativistic all-order method. Therefore, the combination
of the experimental data and theoretical calculations allows us to determine
the np-(n-1)d matrix elements and their uncertainties. We compare these values
with our all-order calculations of the np-(n-1)d matrix elements in K and Rb
for a benchmark test of the accuracy of the all-order method for transitions
involving nd states. Such matrix elements are of special interest for many
applications, such as determination of magic wavelengths in alkali-metal atoms
for state-insensitive cooling and trapping and determination of blackbody
radiation shifts in optical frequency standards with ions.
\\ ( http://arxiv.org/abs/0709.0014 , 10kb)
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\\
arXiv:0709.0130
Date: Sun, 2 Sep 2007 21:26:16 GMT (52kb)

Title: Magic wavelengths for the np-ns transitions in alkali-metal atoms
Authors: Bindiya Arora, M. S. Safronova, and Charles W. Clark
Categories: physics.atom-ph
Comments: 12 pages, 8 figures
\\
Extensive calculations of the electric-dipole matrix elements in alkali-metal
atoms are conducted using the relativistic all-order method. This approach is a
linearized version of the coupled-cluster method, which sums infinite sets of
many-body perturbation theory terms. All allowed transitions between the lowest
ns, np_1/2, np_3/2 states and a large number of excited states are considered
in these calculations and their accuracy is evaluated. The resulting
electric-dipole matrix elements are used for the high-precision calculation of
frequency-dependent polarizabilities of the excited states of alkali-metal
atoms. We find magic wavelengths in alkali-metal atoms for which the ns and
np_1/2 and np_3/2 atomic levels have the same ac Stark shifts, which
facilitates state-insensitive optical cooling and trapping.
\\ ( http://arxiv.org/abs/0709.0130 , 52kb)
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\\
arXiv:0709.0359
Date: Tue, 4 Sep 2007 08:15:22 GMT (125kb)

Title: Adiabatic Fidelity for Atom-Molecule Conversion in a Nonlinear
Three-Level $\Lambda$-system
Authors: Shao-Ying Meng, Li-Bin Fu, Jie Liu
Categories: cond-mat.other
Comments: 4 pages, 5 figures
\\
We investigate the dynamics of the population transfer for atom-molecule
three-level $\Lambda$-system on stimulated Raman adiabatic passage(STIRAP). We
find that the adiabatic fidelity for the coherent population trapping(CPT)
state or dark state, as the function of the adiabatic parameter, approaches to
unit in a power law. The power exponent however is much less than the
prediction of linear adiabatic theorem. We further discuss how to achieve
higher adiabatic fidelity for the dark state through optimizing the external
parameters of STIRAP. Our discussions are helpful to gain higher atom-molecule
conversion yield in practical experiments.
\\ ( http://arxiv.org/abs/0709.0359 , 125kb)
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arXiv:0709.0362
Date: Tue, 4 Sep 2007 08:29:58 GMT (230kb)

Title: Non-perturbative renormalization-group approach to zero-temperature Bose
systems
Authors: N. Dupuis and K. Sengupta
Categories: cond-mat.other
Comments: 6 pages, 8 figures
\\
We use a non-perturbative renormalization-group technique to study
interacting bosons at zero temperature. Our approach reveals the instability of
the Bogoliubov fixed point when $d\leq 3$ and yields the exact infrared
behavior in all dimensions $d>1$ within a rather simple theoretical framework.
It also enables to compute the low-energy properties in terms of the parameters
of a microscopic model. In one-dimension and for not too strong interactions,
it yields a good picture of the Luttinger-liquid behavior of the superfluid
phase.
\\ ( http://arxiv.org/abs/0709.0362 , 230kb)
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arXiv:0709.0368
Date: Tue, 4 Sep 2007 09:05:18 GMT (20kb)

Title: Vortex spectrum in superfluid turbulence: interpretation of a recent
   experiment
Authors: Philippe-Emmanuel P.-E. Roche (NEEL), Carlo F. Barenghi
Categories: cond-mat.other
Comments: Submitted for publication
   http://crtbt.grenoble.cnrs.fr/helio/GROUP/infa.html
   http://www.mas.ncl.ac.uk/~ncfb/
Proxy: ccsd hal-00169495
\\
   We discuss a recent experiment in which the spectrum of the vortex line
density fluctuations has been measured in superfluid turbulence. The observed
frequency dependence of the spectrum, $f^{-5/3}$, disagrees with classical
vorticity spectra if, following the literature, the vortex line density is
interpreted as a measure of the vorticity or enstrophy. We argue that the
disagrement is solved if the vortex line density field is decomposed into a
polarised field (which carries most of the energy) and an isotropic field
(which is responsible for the spectrum).
\\ ( http://arxiv.org/abs/0709.0368 , 20kb)
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arXiv:0709.0388
Date: Tue, 4 Sep 2007 10:34:34 GMT (626kb)

Title: Effects of a Fluctuating Interface between a Superfluid and a Polarized
Fermi Gas
Authors: Hui Zhai and Dung-Hai Lee
Categories: cond-mat.supr-con cond-mat.mes-hall
Comments: 4 pages, 3 figures
\\
Motivated by recent experiments in trapped Fermi gas with spin population
imbalance, we discuss the effects of the quantum and thermal fluctuations of
the interface between a fully paired superfluid core and a fully polarized
Fermi gas. We demonstrate that even if there is no true partially polarized
thermodynamic phase in bulk, the interface fluctuation can give rise to a
partially polarized transition regime in trap. Our theory yields a definite
prediction for the functional forms of the spatial profile of spin polarization
and pairing gap, and we show that the spin-resolved density profiles measured
by both the MIT and Rice groups obey this function form. We also show that
sufficient large fluctuation will lead to a visibly unequal density even at the
center of the cloud. We hope this picture can shed lights on the controversial
discrepancies in recent experiments.
\\ ( http://arxiv.org/abs/0709.0388 , 626kb)
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arXiv:0709.0405
Date: Tue, 4 Sep 2007 12:12:08 GMT (17kb)

Title: Metastability of persistent currents in trapped gases of atoms
Authors: K. Karkkainen (1), J. Christensson (1), G. Reinisch (2), G. M.
Kavoulakis (1), S. M. Reimann (1) ((1) LTH, Lund, (2) Nice)
Categories: cond-mat.other
Comments: 7 pages, RevTex, 5 figures
\\
We examine the conditions that give rise to metastable, persistent currents
in a trapped Bose-Einstein condensate. A necessary condition for the stability
of persistent currents is that the trapping potential is not a monotonically
increasing function of the distance from the trap center. Persistent currents
also require that the interatomic interactions are sufficiently strong and
repulsive. Finally, any off-center vortex state is shown to be unstable, while
a driven gas shows hysteresis.
\\ ( http://arxiv.org/abs/0709.0405 , 17kb)
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arXiv:0709.0499
Date: Tue, 4 Sep 2007 18:48:24 GMT (116kb)

Title: Scattering Models for Ultracold Atoms
Authors: Eric Braaten, Masaoki Kusunoki and Dongqing Zhang
Categories: cond-mat.other
Comments: 60 pages, 6 figures
\\
We present a review of scattering models that can be used to describe the
low-energy behavior of identical bosonic atoms. In the simplest models, the
only degrees of freedom are atoms in the same spin state. More elaborate models
have other degrees of freedom, such as atoms in other spin states or diatomic
molecules. The parameters of the scattering models are specified by giving the
S-wave phase shifts for scattering of atoms in the spin state of primary
interest. The models are formulated as local quantum field theories and the
renormalization of their coupling constants is determined. Some of the
parameters can be constrained by renormalizability or by the absence of
negative-norm states. The Green's functions that describe the evolution of
two-atom states are determined analytically. They are used to determine the
T-matrix elements for atom-atom scattering and the binding energies of diatomic
molecules. The scattering models all exhibit universal behavior as the
scattering length in a specific spin state becomes large.
\\ ( http://arxiv.org/abs/0709.0499 , 116kb)
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arXiv:0709.0343
Date: Tue, 4 Sep 2007 07:28:34 GMT (670kb)

Title: Exactly-solvable coupled-channel potential models of atom-atom magnetic
Feshbach resonances from supersymmetric quantum mechanics
Authors: Andrey M. Pupasov, Boris F. Samsonov, Jean-Marc Sparenberg
Categories: quant-ph
Comments: 19 pages, 15 figures
\\
Starting from a system of $N$ radial Schr\"odinger equations with a vanishing
potential and finite threshold differences between the channels, a coupled $N
\times N$ exactly-solvable potential model is obtained with the help of a
single non-conservative supersymmetric transformation. The obtained potential
matrix, which subsumes a result obtained in the literature, has a compact
analytical form, as well as its Jost matrix. It depends on $N (N+1)/2$
unconstrained parameters and on one upper-bounded parameter, the factorization
energy. A detailed study of the model is done for the $2\times 2$ case: a
geometrical analysis of the zeros of the Jost-matrix determinant shows that the
model has 0, 1 or 2 bound states, and 0 or 1 resonance; the potential
parameters are explicitly expressed in terms of its bound-state energies, of
its resonance energy and width, or of the open-channel scattering length, which
solves schematic inverse problems. As a first physical application,
exactly-solvable $2\times 2$ atom-atom interaction potentials are constructed,
for cases where a magnetic Feshbach resonance interplays with a bound or
virtual state close to threshold, which results in a large background
scattering length.
\\ ( http://arxiv.org/abs/0709.0343 , 670kb)
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arXiv:0709.0352
Date: Tue, 4 Sep 2007 07:55:18 GMT (78kb)

Title: Macroscopic Entanglement of a Bose Einstein Condensate on a
Superconducting Atom Chip
Authors: Mandip Singh
Categories: quant-ph
Comments: 4 Pages, Two figures
\\
We propose and analyse a practically implementable scheme to generate
macroscopic entanglement of a Bose-Einstein condensate in a micro-magnetic trap
magnetically coupled to a superconducting loop. We treat the superconducting
loop in a quantum superposition of two different flux states coupled with the
magnetic trap to generate macroscopic entanglement. Our scheme also provides a
platform to realise interferometry of entangled atoms through the Bose-Einstein
condensate and to explore physics at the quantum-classical interface.
\\ ( http://arxiv.org/abs/0709.0352 , 78kb)
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arXiv:0709.0527
Date: Tue, 4 Sep 2007 20:13:07 GMT (564kb,D)

Title: Quantum Non-Demolition Detection of Strongly Correlated Systems
Authors: Kai Eckert, Oriol Romero-Isart, Mirta Rodriguez, Maciej Lewenstein,
   Eugene S. Polzik and Anna Sanpera
Categories: cond-mat.other
Comments: Accepted for publication in Nature Physics. This is the original
   submitted version
\\
   Preparation, manipulation, and detection of strongly correlated states of
quantum many body systems are among the most important goals and challenges of
modern physics. Ultracold atoms offer an unprecedented playground for
realization of these goals. Here we show how strongly correlated states of
ultracold atoms can be detected in a quantum non-demolition scheme, that is, in
the fundamentally least destructive way permitted by quantum mechanics. In our
method, spatially resolved components of atomic spins couple to quantum
polarization degrees of freedom of light. In this way quantum correlations of
matter are faithfully mapped on those of light; the latter can then be
efficiently measured using homodyne detection. We illustrate the power of such
spatially resolved quantum noise limited polarization measurement by applying
it to detect various standard and "exotic" types of antiferromagnetic order in
lattice systems and by indicating the feasibility of detection of superfluid
order in Fermi liquids.
\\ ( http://arxiv.org/abs/0709.0527 , 564kb)
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arXiv:0709.0605
Date: Wed, 5 Sep 2007 13:58:59 GMT (518kb)

Title: AC-induced superfluidity
Authors: Andre Eckardt and Martin Holthaus
Categories: cond-mat.other
Comments: 6 pages, 4 figures
\\
We argue that a system of ultracold bosonic atoms in a tilted optical lattice
can become superfluid in response to resonant AC forcing. Among others, this
allows one to prepare a Bose-Einstein condensate in a state associated with a
negative effective mass. Our reasoning is backed by both exact numerical
simulations for systems consisting of few particles, and by a theoretical
approach based on Floquet-Fock states.
\\ ( http://arxiv.org/abs/0709.0605 , 518kb)
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\\
arXiv:0709.0656
Date: Wed, 5 Sep 2007 14:00:02 GMT (900kb)

Title: Hidden Fermi Liquid: The Secret of High Tc Cuprates
Authors: Philip W Anderson
Categories: cond-mat.str-el cond-mat.supr-con
\\
I present a formalism for dealing directly with the effects of the Gutzwiller
projection, which is implicit in the t-J model widely believed to underly the
phenomenology of the high-Tc cuprates. I suggest that a true BCS condensation
from a Fermi liquid state takes place, but in the unphysical space prior to
projection. The theory which results upon projection does not follow
conventional rules of diagram theory and in fact in the normal state is a Z=0
non-Fermi liquid. Anomalous properties of this strange metal normal state are
predicted and compared to experiments.
\\ ( http://arxiv.org/abs/0709.0656 , 900kb)
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\\
arXiv:0709.0698
Date: Wed, 5 Sep 2007 16:39:22 GMT (192kb)

Title: Probing two-fluid hydrodynamics in a trapped Fermi superfluid at
unitarity
Authors: Edward Taylor, Hui Hu, Xia-Ji Liu, Allan Griffin
Categories: cond-mat.other
Comments: 5 pages, 3 figures
\\
We develop a variational approach to calculate the density response function
at finite temperatures of the lowest-lying two-fluid modes in a trapped
two-component Fermi superfluid close to a Feshbach resonance. The out-of-phase
oscillations, which are the analogue in trapped gases of second sound in
uniform superfluids, have so far not been observed in cold-atom experiments. We
show that these modes are observable via two-photon Bragg scattering, whose
spectrum is proportional to the imaginary part of density response function. We
predict pronounced peaks for the out-of-phase modes in the Bragg scattering
spectrum at unitarity at finite temperatures. This provides strong evidence for
superfluidity at unitarity and a promising way to probe the unitarity equation
of state.
\\ ( http://arxiv.org/abs/0709.0698 , 192kb)
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\\
arXiv:0709.0613
Date: Wed, 5 Sep 2007 10:29:24 GMT (14kb)

Title: Complementarity and uncertainty relations for matter wave interferometry
Authors: K.-P. Marzlin, B. C. Sanders, and P. L. Knight
Categories: quant-ph
Comments: four pages, one figure
\\
We provide a rigorous quantitative connection between the complementarity
relations of path information vs fringe visibility for a particle in an
interferometer and uncertainty relations between position and modular momentum.
This theory is applied to atom interferometry wherein spontaneously emitted
photons can provide path information, and we show that the metamaterial
`perfect lens' enables atom interferometry to reach an extremum of this
complementarity trade-off.
\\ ( http://arxiv.org/abs/0709.0613 , 14kb)
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\\
arXiv:0709.0716
Date: Wed, 5 Sep 2007 17:49:31 GMT (47kb)

Title: Maximum Entanglement in Squeezed Boson and Fermion States
Authors: F.C. Khanna, J.M.C. Malbouisson, A.E. Santana, E.S. Santos
Categories: quant-ph
Comments: 4 pages
Journal-ref: Phys. Rev A {\bf 76}, 022109 (2007)
DOI: 10.1103/PhysRevA.76.022109
\\
A class of squeezed boson and fermion states is studied with particular
emphasis on the nature of entanglement. We first investigate the case of
bosons, considering two-mode squeezed states. Then we construct the fermion
version to show that such states are maximum entangled, for both bosons and
fermions. To achieve these results, we demonstrate some relations involving
squeezed boson states. The generalization to the case of fermions is made by
using Grassmann variables.
\\ ( http://arxiv.org/abs/0709.0716 , 47kb)
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\\
arXiv:0709.0817
Date: Thu, 6 Sep 2007 10:08:42 GMT (21kb)

Title: Competition between final-state and pairing-gap effects in the
radio-frequency spectra of ultracold Fermi atoms
Authors: A. Perali, P. Pieri, G.C. Strinati
Categories: cond-mat.supr-con cond-mat.other
Comments: 4 pages, 3 figures
\\
The radio-frequency spectra of ultracold Fermi atoms are calculated by
including final-state interactions affecting the excited level of the
transition, and compared quantitatively with the experimental data. This
inclusion reveals a competition between pairing-gap effects which tend to push
the oscillator strength toward high frequencies away from threshold, and
final-state effects which tend instead to pull the oscillator strength toward
threshold. As a result of this competition, the position of the peak of the
spectra cannot be simply related to the value of the pairing gap, whose
extraction thus requires support from theoretical calculations.
\\ ( http://arxiv.org/abs/0709.0817 , 21kb)
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\\
arXiv:0709.0895
Date: Thu, 6 Sep 2007 15:49:48 GMT (207kb,D)

Title: Vortex nucleation in Bose-Einstein Condensates subject to light induced
effective magnetic fields
Authors: D. R. Murray, P \"Ohberg, Dami\'a Gomila and Stephen M. Barnett
Categories: cond-mat.other
Comments: 7 pages, 7 figures
\\
We numerically simulate vortex nucleation in a Bose-Einstein Condensate (BEC)
subject to an effective magnetic field. The effective magnetic field is
generated from the interplay between light with a non-trivial phase structure
and the BEC, and can be shaped and controlled by appropriate modifications to
the phase and intensity of the light. We demonstrate that the nucleation of
vortices is seeded by instabilities in surface excitations which are coupled to
by an asymmetric trapping potential (similar to the case of condensates subject
to mechanical rotation) and show that this picture also holds when the applied
effective magnetic field is not homogeneous. The eventual configuration of
vortices in the cloud depends on the geometry of the applied field.
\\ ( http://arxiv.org/abs/0709.0895 , 207kb)
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\\
arXiv:0708.4304 (*cross-listing*)
Date: Fri, 31 Aug 2007 09:31:00 GMT (463kb,D)

Title: Control of atomic currents using a quantum stirring device
Authors: Moritz Hiller, Tsampikos Kottos, Doron Cohen
Categories: cond-mat.mes-hall cond-mat.other quant-ph
Comments: 5 pages, 4 figures
\\
We propose a BEC stirring device which can be regarded as the incorporation
of a quantum pump into a closed circuit: it produces a DC circulating current
in response to a cyclic adiabatic change of two control parameters of an
optical trap. We demonstrate the feasibility of this concept and point out that
such device can be utilized in order to probe the interatomic interactions.
\\ ( http://arxiv.org/abs/0708.4304 , 463kb)
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\\
arXiv:0709.0754
Date: Thu, 6 Sep 2007 16:51:51 GMT (951kb)

Title: Coherent Control of Trapped Bosons
Authors: Analabha Roy, Linda E. Reichl
Categories: physics.atom-ph
Comments: 17 figures
\\
We investigate the quantum behavior of a mesoscopic two-boson system produced
by number-squeezing ultracold gases of alkali metal atoms. The quantum Poincare
maps of the wavefunctions are affected by chaos in those regions of the phase
space where the classical dynamics produces features that are comparable to
hbar. We also investigate the possibility for quantum control in the dynamics
of excitations in these systems. Controlled excitations are mediated by pulsed
signals that cause Stimulated Raman Adiabatic passage (STIRAP) from the ground
state to a state of higher energy. The dynamics of this transition is affected
by chaos caused by the pulses in certain regions of the phase space. A
transition to chaos can thus provide a method of controlling STIRAP.
\\ ( http://arxiv.org/abs/0709.0754 , 951kb)
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\\
arXiv:0709.0827
Date: Thu, 6 Sep 2007 10:48:42 GMT (162kb)

Title: Sympathetic cooling in a mixture of diamagnetic and paramagnetic atoms
Authors: S. Tassy, N. Nemitz, F. Baumer, C. H\"ohl, A. Bat\"ar, A. G\"orlitz
Categories: physics.atom-ph
Comments: 4 pages, 4 figures
\\
We have experimentally realized a hybrid trap for ultracold paramagnetic
rubidium and diamagnetic ytterbium atoms by combining a bichromatic optical
dipole trap for ytterbium with a Ioffe-Pritchard-type magnetic trap for
rubidium. In this hybrid trap, sympathetic cooling of five different ytterbium
isotopes through elastic collisions with rubidium was achieved. A strong
dependence of the interspecies collisional cross section on the mass of the
ytterbium isotope was observed.
\\ ( http://arxiv.org/abs/0709.0827 , 162kb)
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The replacements:

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arXiv:0708.4304
Date: Fri, 31 Aug 2007 09:31:00 GMT (463kb,D)

More soon,
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 Sat Oct 06 2007 - 22:07:09 EST

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