[Matts-arxiv] Matt's arXiv selection: week ending 10 September 2010

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Thu, 28 Oct 2010 22:05:43 +1000

Dear subscribers,

This week's selection was compiled by Jacopo Sabbatini, and contains 36 new
abstracts and 15 replacements.

Date: Thu, 2 Sep 2010 22:26:42 GMT (848kb)

Title: Anderson localization in Bose-Einstein condensates
Authors: Giovanni Modugno
Categories: cond-mat.dis-nn cond-mat.quant-gas quant-ph
Comments: 15 pages review, to appear in Reports on Progress in Physics
   The understanding of disordered quantum systems is still far from being
complete, despite many decades of research on a variety of physical systems. In
this review we discuss how Bose-Einstein condensates of ultracold atoms in
disordered potentials have opened a new window for studying fundamental
phenomena related to disorder. In particular, we point our attention to recent
experimental studies on Anderson localization and on the interplay of disorder
and weak interactions. These realize a very promising starting point for a
deeper understanding of the complex behaviour of interacting, disordered
\\ ( http://arxiv.org/abs/1009.0555 , 848kb)
Date: Fri, 3 Sep 2010 05:18:14 GMT (512kb,D)

Title: Feedback control of an interacting Bose-Einstein condensate using
   phase-contrast imaging
Authors: Stuart S. Szigeti, Michael R. Hush, Andre R. R. Carvalho and Joseph J.
Categories: physics.atom-ph cond-mat.quant-gas
Comments: 12 pages, 5 figures
   The linewidth of an atom laser is limited by density fluctuations in the
Bose-Einstein condensate (BEC) from which the atom laser beam is outcoupled. In
this paper we show that a stable spatial mode for an interacting BEC can be
generated using a realistic control scheme that includes the effects of the
measurement backaction. This model extends the feedback theory, based on a
phase-contrast imaging setup, presented in \cite{Szigeti:2009}. In particular,
it is applicable to a BEC with large interatomic interactions and solves the
problem of inadequacy of the mean-field (coherent state) approximation by
utilising a fixed number state approximation. Our numerical analysis shows the
control to be more effective for a condensate with a large nonlinearity.
\\ ( http://arxiv.org/abs/1009.0587 , 512kb)
arXiv:1009.0640 (*cross-listing*)
Date: Fri, 3 Sep 2010 11:57:34 GMT (151kb,D)

Title: Atomic Fock states by gradual trap reduction: from sudden to adiabatic
Authors: D.Sokolovski, M.Pons, A.del Campo and J.G.Muga
Categories: quant-ph cond-mat.quant-gas
   We investigate the possibility to form high fidelity atomic Fock states by
gradual reduction of a quasi one dimensional trap containing spin polarized
fermions or strongly interacting bosons in the Tonk-Girardeau regime. Making
the trap shallower and simultaneously squeezing it can lead to the preparation
of an ideal atomic Fock state as one approaches either the sudden or the
adiabatic limits. Nonetheless, the fidelity of the resulting state is shown to
exhibit a non-monotonic behaviour with the time scale in which the trapping
potential is changed.
\\ ( http://arxiv.org/abs/1009.0640 , 151kb)
arXiv:1009.0653 (*cross-listing*)
Date: Fri, 3 Sep 2010 13:09:43 GMT (435kb)

Title: Non-Linear Dynamics of Continuously Measured Bose-Einstein Condensates
   in One-Dimensional Harmonic Traps
Authors: T.Yu. Ivanova, M.S. Samoylova, D.A. Ivanov
Categories: quant-ph cond-mat.quant-gas
Comments: 8 pages, 5 figures
   Continuous center-of-mass position measurements performed on an interacting
harmonically trapped Bose-gas are considered. Using both semi-analytical
mean-field approach and completely quantum numerical technique based on
positive P-representation, it is demonstrated that the atomic delocalization
due to the measurement back action is smaller for a strongly interacting gas.
The numerically calculated second-order correlation functions demonstrate
appearance of atomic bunching as a result of the center-of-mass measurement.
Though being rather small the bunching is present also for strongly interacting
gas which is in contrast with the case of unperturbed gas. The performed
analysis allows to speculate that for relatively strong interactions the size
of atomic bunches can become smaller than the initial cloud size resulting in a
sort of squeezing effect.
\\ ( http://arxiv.org/abs/1009.0653 , 435kb)
Date: Fri, 3 Sep 2010 14:04:27 GMT (623kb)

Title: Polaronic slowing of fermionic impurities in lattice Bose-Fermi mixtures
Authors: Antonio Privitera and Walter Hofstetter
Categories: cond-mat.quant-gas
Comments: 13 pages, 5 figures
   We generalize the application of small polaron theory to ultracold gases of
Ref. [\onlinecite{jaksch_njp1}] to the case of Bose-Fermi mixtures, where both
components are loaded into an optical lattice. In a suitable range of
parameters, the mixture can be described within a Bogoliubov approach in the
presence of fermionic (dynamic) impurities and an effective description in
terms of polarons applies. In the dilute limit of the slow impurity regime, the
hopping of fermionic particles is exponentially renormalized due to polaron
formation, regardless of the sign of the Bose-Fermi interaction. This should
lead to clear experimental signatures of polaronic effects, once the regime of
interest is reached. The validity of our approach is analyzed in the light of
currently available experiments. We provide results for the hopping
renormalization factor for different values of temperature, density and
Bose-Fermi interaction for three-dimensional $^{87}\rm{Rb}-^{40}\rm{K}$
mixtures in optical lattice.
\\ ( http://arxiv.org/abs/1009.0675 , 623kb)
arXiv:1009.0759 (*cross-listing*)
Date: Fri, 3 Sep 2010 20:03:31 GMT (136kb)

Title: Momentum-space engineering of gaseous Bose-Einstein condensates
Authors: Mark Edwards, Brandon Benton, Jeffrey Heward, Charles W. Clark
Categories: cond-mat.quant-gas quant-ph
Comments: 13 pages, 4 figures
   We show how the momentum distribution of gaseous Bose-Einstein condensates
can be shaped by applying a sequence of standing--wave laser pulses. We present
a theory of the effect of such a pulse sequence on the condensate wave function
in momentum space. We generalize the previous result to the case of N pulses of
arbitrary intensity separated by arbitrary intervals and show how these
parameters can be engineered to produce a desired final momentum distribution.
We find that several momentum distributions, important in atom interferometry
applications, can be engineered with high fidelity with two or three pulses.
\\ ( http://arxiv.org/abs/1009.0759 , 136kb)
Date: Sat, 4 Sep 2010 00:16:27 GMT (416kb)

Title: Isentropic Curves at Magnetic Phase Transitions
Authors: J.D. Cone, A. Zujev and R.T. Scalettar
Categories: cond-mat.quant-gas
   Experiments on cold atom systems in which a lattice potential is ramped up on
a confined cloud have raised intriguing questions about how the temperature
varies along isentropic curves, and how these curves intersect features in the
phase diagram. In this paper, we study the isentropic curves of two models of
magnetic phase transitions- the classical Blume-Capel Model (BCM) and the Fermi
Hubbard Model (FHM). Both Mean Field Theory (MFT) and Monte Carlo (MC) methods
are used. The isentropic curves of the BCM generally run parallel to the phase
boundary in the Ising regime of low vacancy density, but intersect the phase
boundary when the magnetic transition is mainly driven by a proliferation of
vacancies. Adiabatic heating occurs in moving away from the phase boundary. The
isentropes of the half-filled FHM have a relatively simple structure, running
parallel to the temperature axis in the paramagnetic phase, and then curving
upwards as the antiferromagnetic transition occurs. However, in the doped case,
where two magnetic phase boundaries are crossed, the isentrope topology is
considerably more complex.
\\ ( http://arxiv.org/abs/1009.0791 , 416kb)
Date: Sat, 4 Sep 2010 10:56:58 GMT (829kb,D)

Title: Cascade of vortex loops initiated by a single reconnection of quantum
Authors: Miron Kursa, Konrad Bajer and Tomasz Lipniacki
Categories: cond-mat.other physics.flu-dyn
Comments: 9 pages, 5 figures, submitted to APS (preprint)
MSC-class: 76A25
   We demonstrate that a single reconnection of two quantum vortices can lead to
creation of a cascade of vortex rings. Our analysis, motivated by the
analytical solution in LIA, involves high-resolution Biot-Savart and
Gross-Pitaevskii simulations. The latter showed that the rings cascade starts
on the atomic scale, with rings diameters orders of magnitude smaller than the
characteristic line spacing in the tangle. So created vortex rings may
penetrate the tangle and annihilate on the boundaries. This provides an
efficient mechanism of the vortex tangle decay in very low temperatures.
\\ ( http://arxiv.org/abs/1009.0823 , 829kb)
Date: Sun, 5 Sep 2010 16:03:54 GMT (159kb)

Title: Study of Efimov physics in two nuclear-spin sublevels of 7Li
Authors: Noam Gross, Zav Shotan, Olga Machtey, Servaas Kokkelmans and Lev
Categories: cond-mat.quant-gas
Comments: 15 pages, 7 figures
   Efimov physics in two nuclear-spin sublevels of bosonic lithium is studied
and it is shown that the positions and widths of recombination minima and
Efimov resonances are identical for both states within the experimental errors
which indicates that the short-range physics is nuclear-spin independent. We
also find that the Efimov features are universally related across Feshbach
resonances. These results crucially depend on careful mapping between the
scattering length and the applied magnetic field which we achieve by
characterization of the two broad Feshbach resonances in the different states
by means of rf-spectroscopy of weakly bound molecules. By fitting the binding
energies numerically with a coupled channels calculation we precisely determine
the absolute positions of the Feshbach resonances and the values of the singlet
and triplet scattering lengths.
\\ ( http://arxiv.org/abs/1009.0926 , 159kb)
Date: Sun, 5 Sep 2010 21:13:46 GMT (174kb)

Title: Breakdown of universality in few-boson systems
Authors: A. Deltuva and R. Lazauskas
Categories: physics.atom-ph nucl-th
Journal-ref: Phys. Rev. A 82, 012705 (2010)
DOI: 10.1103/PhysRevA.82.012705
   We develop a series of resonant short-range two-boson potentials reproducing
the same two-body low-energy observables and apply them in three- and four-body
calculations. We demonstrate that the universal behavior predicted by effective
field theory may be strongly violated and analyze the conditions for this
\\ ( http://arxiv.org/abs/1009.0951 , 174kb)
Date: Mon, 6 Sep 2010 07:14:07 GMT (641kb)

Title: Breathing Oscillations in Bose - Fermi Mixing Gases with Yb atoms in the
   Largely Prolate Deformed Traps
Authors: Tomoyuki Maruyama, Hiroyuki Yabu
Categories: cond-mat.quant-gas
Comments: 27 pages, 12 figures
   We study the breathing oscillations in bose-fermi mixtures with Yb isotopes
in the largely prolate deformed trap, which are realized by Kyoto group. We
choose the three combinations of the Yb isotopes, Yb170-Yb171, Yb170-Yb173 and
Yb174-Yb173, whose boson-fermion interactions are weakly repulsive, strongly
attractive and strongly repulsive. The collective oscillations in the deformed
trap are calculated in the dynamical time-development approach, which is
formulated with the time-dependent Gross-Pitaevskii and the Vlasov equations.
We analyze the results in the time-development approach with the intrinsic
oscillation modes of the deformed system, which are obtained using the scaling
method, and show that the damping and forced-oscillation effects of the
intrinsic modes give time-variation of oscillations, especially, in the fermion
transverse mode.
\\ ( http://arxiv.org/abs/1009.0975 , 641kb)
Date: Mon, 6 Sep 2010 09:14:10 GMT (11kb)

Title: Squeezing Inequalities and Entanglement for Identical Particles
Authors: F. Benatti, R. Floreanini, U. Marzolino
Categories: quant-ph cond-mat.quant-gas
Comments: 13 pages, LaTex
   By identifying non-local effects in systems of identical Bosonic qubits
through correlations of their commuting observables, we show that entanglement
is not necessary to violate certain squeezing inequalities that hold for
distinguishable qubits and that spin squeezing may not be necessary to achieve
sub-shot noise accuracies in ultra-cold atom interferometry.
\\ ( http://arxiv.org/abs/1009.0995 , 11kb)
Date: Mon, 6 Sep 2010 14:36:02 GMT (433kb,D)

Title: Supersolid phases of dipolar bosons in optical lattices with a staggered
Authors: O. Tieleman, A. Lazarides, and C. Morais Smith
Categories: cond-mat.quant-gas
Comments: 10+ pages
   We present the theoretical mean-field zero-temperature phase diagram of a
Bose-Einstein condensate (BEC) with dipolar interactions loaded into an optical
lattice with a staggered flux. Apart from uniform superfluid, checkerboard
supersolid and striped supersolid phases, we identify several supersolid phases
with staggered vortices, which can be seen as combinations of supersolid phases
found in earlier work on dipolar BECs and a staggered-vortex phase found for
bosons in optical lattices with staggered flux. By allowing for different
phases and densities on each of the four sites of the elementary plaquette,
more complex phase patterns are found.
\\ ( http://arxiv.org/abs/1009.1072 , 433kb)
arXiv:1009.1073 (*cross-listing*)
Date: Mon, 6 Sep 2010 14:43:09 GMT (505kb)

Title: Stochastic quantum dynamics in 1D and lattice systems
Authors: J. Ruostekoski and A. D. Martin
Categories: cond-mat.quant-gas quant-ph
Comments: Chapter in "Non-Equilibrium Quantum Gases at Finite Temperatures",
   ed. M. Davis, S. Gardiner, N. Nygaard, N. Proukakis, and M. Szymanska (World
   Scientific, 2010)
   We show that stochastic phase-space methods within the truncated Wigner
approximation can be used to solve non-equilibrium dynamics of bosonic atoms in
1d traps. We consider systems both with and without an optical lattice and
address different approximations in stochastic synthesization of quantum
statistical correlations of the initial atomic field operator. We also present
a numerically efficient projection method for analyzing correlation functions
of the simulation results. Physical examples demonstrate non-equilibrium
quantum dynamics of solitons and atom number squeezing in optical lattices in
which case we, e.g., numerically track the soliton coordinates and calculate
quantum mechanical expectation values and uncertainties for the position of the
\\ ( http://arxiv.org/abs/1009.1073 , 505kb)
arXiv:1009.1295 (*cross-listing*)
Date: Tue, 7 Sep 2010 13:59:58 GMT (32kb)

Title: Efimov physics in bosonic atom-trimer scattering
Authors: A. Deltuva
Categories: physics.atm-clus cond-mat.quant-gas nucl-th
Comments: 4 pages, 4 figures, 3 tables
   Bosonic atom-trimer scattering is studied in the unitary limit using
momentum-space equations for four-particle transition operators. The impact of
the Efimov effect on the atom-trimer scattering observables is explored and a
number of universal relations is established. Positions and widths of tetramer
resonances are determined.
\\ ( http://arxiv.org/abs/1009.1295 , 32kb)
Date: Tue, 7 Sep 2010 14:46:10 GMT (33kb)

Title: Bose-Hubbard model with occupation dependent parameters
Authors: Omjyoti Dutta, Andre Eckardt, Philipp Hauke, Boris Malomed, and Maciej
Categories: cond-mat.quant-gas
Comments: 14 pages, 4 figures
   We study the ground-state properties of ultracold bosons in an optical
lattice in the regime of strong interactions. The system is described by a
non-standard Bose-Hubbard model with both occupation-dependent tunneling and
on-site interaction parameters. We find that for sufficiently strong coupling,
the system features a phase-transition from a Mott insulator with one particle
per site to a superfluid of spatially extended particle pairs living on top of
the Mott background. Increasing the interaction further, a superfluid of
particle pairs localized on a single site (rather than being extended) on top
of the Mott background appears. This happens at the same time when the
Mott-insulator phase with 2 particles per site is destroyed completely by
particle-hole fluctuations for arbitrary small tunneling. In another regime,
characterized by weak interaction, but high occupation numbers, we observe a
dynamical instability in the superfluid excitation spectrum. The new ground
state is a superfluid, forming a 2D slab, localized along one spatial direction
that is spontaneously chosen.
\\ ( http://arxiv.org/abs/1009.1313 , 33kb)
arXiv:1009.1358 (*cross-listing*)
Date: Tue, 7 Sep 2010 18:52:26 GMT (2171kb,D)

Title: Combined quantum state preparation and laser cooling of a continuous
   beam of cold atoms
Authors: Gianni Di Domenico, Laurent Devenoges, Claire Dumas, Pierre Thomann
Categories: physics.atom-ph quant-ph
   We use two-laser optical pumping on a continuous atomic fountain in order to
prepare cold cesium atoms in the same quantum ground state. A first laser
excites the F=4 ground state to pump the atoms toward F=3 while a second
pi-polarized laser excites the F=3 -> F'=3 transition of the D2 line to produce
Zeeman pumping toward m=0. To avoid trap states, we implement the first laser
in a 2D optical lattice geometry, thereby creating polarization gradients. This
configuration has the advantage of simultaneously producing Sisyphus cooling
when the optical lattice laser is tuned between the F=4 -> F'=4 and F=4 -> F'=5
transitions of the D2 line, which is important to remove the heat produced by
optical pumping. Detuning the frequency of the second pi-polarized laser
reveals the action of a new mechanism improving both laser cooling and state
preparation efficiency. A physical interpretation of this mechanism is
\\ ( http://arxiv.org/abs/1009.1358 , 2171kb)
arXiv:1009.1366 (*cross-listing*)
Date: Tue, 7 Sep 2010 19:03:17 GMT (10kb)

Title: Mapping between Hamiltonians with attractive and repulsive potentials on
   a lattice
Authors: Yogesh N. Joglekar
Categories: cond-mat.quant-gas cond-mat.other quant-ph
Comments: 6 pages, 1 figure
   Through a simple and exact analytical derivation, we show that for a particle
on a lattice, there is a one-to-one correspondence between the spectra in the
presence of an attractive potential $\hat{V}$ and its repulsive counterpart
$-\hat{V}$. For a Hermitian potential, this result implies that the number of
localized states is the same in both, attractive and repulsive, cases although
these states occur above (below) the band-continnum for the repulsive
(attractive) case. For a $\mP\mT$-symmetric potential that is odd under parity,
our result implies that in the $\mP\mT$-unbroken phase, the energy eigenvalues
are symmetric around zero, and that the corresponding eigenfunctions are
closely related to each other.
\\ ( http://arxiv.org/abs/1009.1366 , 10kb)
Date: Tue, 7 Sep 2010 20:03:16 GMT (668kb)

Title: Bogoliubov theory of interacting bosons on a lattice in a synthetic
   magnetic field
Authors: Stephen Powell, Ryan Barnett, Rajdeep Sensarma, Sankar Das Sarma
Categories: cond-mat.quant-gas cond-mat.supr-con
Comments: 22 pages, 7 figures
   We consider theoretically the problem of an artificial gauge potential
applied to a cold atomic system of interacting neutral bosons in a
tight-binding optical lattice. Using the Bose-Hubbard model, we show that an
effective magnetic field leads to superfluid phases with simultaneous spatial
order, which we analyze using Bogoliubov theory. This gives a consistent
expansion in terms of quantum and thermal fluctuations, in which the lowest
order gives a Gross-Pitaevskii equation determining the condensate
configuration. We apply an analysis based on the magnetic symmetry group to
show how the spatial structure of this configuration depends on commensuration
between the magnetic field and the lattice. Higher orders describe the
quasiparticle excitations, whose spectrum combines the intricacy the Hofstadter
butterfly with the characteristic features of the superfluid phase. We use the
depletion of the condensate to determine the range of validity of our
approximations and also to find an estimate for the onset of the Mott insulator
phase. Our theory provides concrete experimental predictions, for both
time-of-flight imagery and Bragg spectroscopy.
\\ ( http://arxiv.org/abs/1009.1389 , 668kb)
Date: Tue, 7 Sep 2010 20:29:24 GMT (124kb)

Title: Three-sublattice ordering of the SU(3) Heisenberg model of three-flavor
   fermions on the square and cubic lattices
Authors: Tamas A. Toth, Andreas M. Laeuchli, Frederic Mila, and Karlo Penc
Categories: cond-mat.str-el cond-mat.quant-gas
Comments: 4 pages, 3 figures
   Combining a semi-classical analysis with exact diagonalizations, we show that
the ground state of the SU(3) Heisenberg model on the square lattice develops
three-sublattice long-range order. This surprising pattern for a bipartite
lattice with only nearest-neighbor interactions is shown to be the consequence
of a subtle quantum order-by-disorder mechanism. By contrast, thermal
fluctuations favor two-sublattice configurations via entropic selection. These
results are shown to extend to the cubic lattice, and experimental implications
for the Mott-insulating states of three-flavor fermionic atoms in optical
lattices are discussed.
\\ ( http://arxiv.org/abs/1009.1398 , 124kb)
Date: Tue, 7 Sep 2010 21:31:03 GMT (174kb)

Title: Itinerant ferromagnetism in a Fermi gas with contact interaction:
   Magnetic properties in a dilute Hubbard model
Authors: Chia-Chen Chang, Shiwei Zhang, David M. Ceperley
Categories: cond-mat.quant-gas cond-mat.str-el
Comments: 4+ pages, 4 figures
   Ground state properties of the repulsive Hubbard model on a cubic lattice are
investigated by means of the auxiliary-field quantum Monte Carlo method. We
focus on low-density systems with varying on-site interaction $U/t$, as a model
relevant to recent experiments on itinerant ferromagnetism in a dilute Fermi
gas with contact interaction. Twist-average boundary conditions are used to
eliminate open-shell effects and large lattice sizes are studied to reduce
finite-size effects. The sign problem is controlled by a generalized
constrained path approximation. We find no ferromagnetic phase transition in
this model. The ground-state correlations are consistent with those of a
paramagnetic Fermi liquid.
\\ ( http://arxiv.org/abs/1009.1409 , 174kb)
Date: Tue, 7 Sep 2010 23:01:03 GMT (36kb)

Title: Supersolidity in electron-hole bilayers with a large density imbalance
Authors: Meera M. Parish, Francesca M. Marchetti, Peter B. Littlewood
Categories: cond-mat.str-el
Comments: 4+ pages, 3 figures
   We consider an electron-hole bilayer in the limit of extreme density
imbalance, where we have a single particle in one layer interacting
attractively with a Fermi liquid in the other parallel layer. Using an
appropriate variational wave function for the dressed exciton, we provide
strong evidence for the existence of the Fulde-Ferrell-Larkin-Ovchninnikov
(FFLO) phase in electron-hole bilayers with a large density imbalance.
Furthermore, within this unusual limit of FFLO, we find that a dilute gas of
minority particles forms excitons that condense into a two-dimensional
\\ ( http://arxiv.org/abs/1009.1420 , 36kb)
Date: Wed, 8 Sep 2010 07:35:08 GMT (1109kb)

Title: Phase diagram of spin-1/2 bosons in one-dimensional optical lattice
Authors: L. de Forges de Parny, M. Traynard, F. H\'ebert, V.G. Rousseau, R.T.
   Scalettar, and G.G. Batrouni
Categories: cond-mat.stat-mech
   Systems of two coupled bosonic species are studied using Mean Field Theory
and Quantum Monte Carlo. The phase diagram is characterized both based on the
mobility of the particles (Mott insulating or superfluid) and whether or not
the system is magnetic (different populations for the two species). The phase
diagram is shown to be population balanced for negative spin-dependent
interactions, regardless of whether it is insulating or superfluid. For
positive spin-dependent interactions, the superfluid phase is always polarized,
the two populations are imbalanced. On the other hand, the Mott insulating
phase with even commensurate filling has balanced populations while the odd
commensurate filling Mott phase has balanced populations at very strong
interaction and polarizes as the interaction gets weaker while still in the
Mott phase.
\\ ( http://arxiv.org/abs/1009.1465 , 1109kb)
Date: Wed, 8 Sep 2010 08:02:06 GMT (310kb)

Title: Internal Josephson Oscillations for Distinct Momenta Bose-Einstein
Authors: Lih-King Lim, T. Troppenz, and C. Morais Smith
Categories: cond-mat.quant-gas
Comments: 4 pages, 3 figures
   The internal Josephson oscillations between an atomic Bose-Einstein
condensate (BEC) and a molecular one are studied for atoms in a square optical
lattice subjected to a staggered gauge field. The system is described by a
Bose-Hubbard model with complex and anisotropic hopping parameters, which are
different for each species, atoms and molecules. When the flux per plaquette
for each species is small, the system oscillates between two conventional
zero-momentum condensates. However, there is a regime of parameters where
Josephson oscillations between a vortex-carrying atomic condensate (finite
momentum BEC) and a conventional zero-momentum molecular condensate may be
realized. The experimental observation of the oscillations between these
qualitatively distinct BEC's is possible with state of the art Ramsey
interference techniques.
\\ ( http://arxiv.org/abs/1009.1471 , 310kb)
Date: Wed, 8 Sep 2010 08:55:41 GMT (941kb)

Title: Two-boson Correlations in Various One-dimensional Traps
Authors: Anna Okopinska, Przemyslaw Koscik
Categories: quant-ph
Comments: 5 pages, 3 figures
Journal-ref: Few-Body System,Volume 45, Numbers 2-4, 223-226 2009
   A one-dimensional system of two trapped bosons which interact through a
contact potential is studied using the optimized configuration interaction
method. The rapid convergence of the method is demonstrated for trapping
potentials of convex and non-convex shapes. The energy spectra, as well as
natural orbitals and their occupation numbers are determined in function of the
inter-boson interaction strength. Entanglement characteristics are discussed in
dependence on the shape of the confining potential.
\\ ( http://arxiv.org/abs/1009.1482 , 941kb)
Date: Wed, 8 Sep 2010 12:10:08 GMT (91kb)

Title: The second critical point for the Perfect Bose gas in
   quasi-one-dimensional traps
Authors: Mathieu Beau (CPT), Valentin A. Zagrebnov (CPT)
Categories: cond-mat.quant-gas
   We present a new model of quasi-one-dimensional trap with some unknown
physical predictions about a second transition, including about a change in
fractions of condensed coherence lengths due to the existence of a second
critical temperature Tm < Tc. If this physical model is acceptable, we want to
challenge experimental physicists in this regard.
\\ ( http://arxiv.org/abs/1009.1511 , 91kb)
arXiv:1009.1552 (*cross-listing*)
Date: Wed, 8 Sep 2010 14:44:33 GMT (58kb)

Title: Simulation of gauge transformations on systems of ultracold atoms
Authors: O. Boada, A. Celi and J.I. Latorre
Categories: cond-mat.quant-gas hep-th quant-ph
Comments: 14 pages, 6 figures
   We show that gauge transformations can be simulated on systems of ultracold
atoms. We discuss observables that are invariant under these gauge
transformations and compute them using a tensor network ansatz that escapes the
phase problem. We determine that the Mott-insulator-to-superfluid critical
point is monotonically shifted as the induced magnetic flux increases. This
result is stable against the inclusion of a small amount of entanglement in the
variational ansatz.
\\ ( http://arxiv.org/abs/1009.1552 , 58kb)
Date: Wed, 8 Sep 2010 16:02:27 GMT (1253kb)

Title: Theoretical confirmation of Feynman's hypothesis on the creation of
   circular vortices in Bose-Einstein condensates: III
Authors: E. Infeld, A. Senatorski and A. A. Skorupski
Categories: cond-mat.quant-gas cond-mat.other
Comments: 10 pages, 7 figures
   In two preceding papers (Infeld and Senatorski 2003 J. Phys.: Condens. Matter
15 5865, and Senatorski and Infeld 2004 J. Phys.: Condens. Matter 16 6589) we
confirmed Feynman's hypothesis on how circular vortices can be created from
oppositely polarized pairs of linear vortices (first paper), and then gave
examples of the creation of several different circular vortices from one linear
pair (second paper). Here in part III, we give two classes of examples of how
the vortices can interact. The first confirms the intuition that the
reconnection processes which join two interacting vortex lines into one,
practically do not occur. The second shows that new circular vortices can also
be created from pairs of oppositely polarized coaxial circular vortices. This
seems to contradict the results for such pairs given in Koplik and Levine 1996
Phys. Rev. Lett. 76 4745.
\\ ( http://arxiv.org/abs/1009.1574 , 1253kb)
arXiv:1009.1599 (*cross-listing*)
Date: Wed, 8 Sep 2010 17:55:06 GMT (398kb)

Title: Persistent currents in Bose gases confined in annular traps
Authors: S. Bargi, F. Malet, G. M. Kavoulakis, S. M. Reimann
Categories: cond-mat.quant-gas quant-ph
Comments: 6 pages, 4 figures
   We examine the problem of stability of persistent currents in a mixture of
two Bose gases trapped in an annular potential. We evaluate the critical
coupling for metastability in the transition from quasi-one to two-dimensional
motion. We also evaluate the critical coupling for metastability in a mixture
of two species as function of the population imbalance. The stability of the
currents is shown to be sensitive to the deviation from one-dimensional motion.
\\ ( http://arxiv.org/abs/1009.1599 , 398kb)
Date: Wed, 8 Sep 2010 20:34:03 GMT (280kb,D)

Title: Do Quenched Spinor Condensates Thermalize?
Authors: Ryan Barnett, Anatoli Polkovnikov, and Mukund Vengalattore
Categories: cond-mat.quant-gas
Comments: 4 pages, 3 figures
   Motivated by recent experiments, we consider the dynamics of spin-one spinor
condensates after a quantum quench from the polar to ferromagnetic state from
varying the quadratic Zeeman field, $q$. We apply the Truncated Wigner
Approximation (TWA) to the spinor system with all spatial and spin degrees of
freedom. For short times, we find full agreement with the linearized Bogoliubov
analysis. For longer times, where the Bogoliubov theory fails, we find that the
system reaches a quasi-steady state. We compute the Bogoliubov spectrum about
the ferromagnetic state with finite $q$ and show that the resulting finite
temperature correlation functions grossly disagree with the full TWA results,
thus indicating that the system does not thermalize even over very long time
scales. We attribute this to the presence of topological defects (i.e. spin
vortices) which prevent the relaxation to the ground state over experimentally
relevant time scales.
\\ ( http://arxiv.org/abs/1009.1646 , 280kb)
Date: Thu, 9 Sep 2010 02:08:49 GMT (1280kb)

Title: Hydrodynamic equation of a spinor dipolar Bose-Einstein condensate
Authors: Kazue Kudo and Yuki Kawaguchi
Categories: cond-mat.quant-gas
Comments: 13 pages, 5 figures
   We introduce equations of motion for spin dynamics in a ferromagnetic
Bose-Einstein condensate with magnetic dipole-dipole interaction, written using
a vector expressing the superfluid velocity and a complex scalar describing the
magnetization. This simple hydrodynamical description affords a straightforward
approach by which to investigate the spin dynamics of the condensate. To
demonstrate the advantages of the description, we illustrate dynamical
instability and magnetic fluctuation preference, which are expressed in
analytical forms.
\\ ( http://arxiv.org/abs/1009.1671 , 1280kb)
Date: Thu, 9 Sep 2010 07:35:56 GMT (1318kb)

Title: Equilibrium Properties of Trapped Dipolar Gases at Finite Temperatures
Authors: Yuki Endo, Takahiko Miyakawa and Tetsuro Nikuni
Categories: cond-mat.other
Comments: 14 pages, 14 figures
   We study the equilibrium properties of dipolar Bose and Fermi gases at finite
temperatures. We recently developed a variational ansatz for the phase-space
distribution function of a dipolar Fermi gas at finite temperatures. We extend
the variational formalism to a Bose gas and discuss the effect of dipolar
interactions with different statistics on the thermal equilibrium, with
particular emphasis on the deformation in momentum space. We examine the
stability of the system by varying the temperature, trap aspect ratio and the
dipole moment. In addition, we discuss how deformation in both real and
momentum space can be observed in the high-temperature regime, which is
relevant for the current experiments at JILA [Ni et al. Science 322, 231
(2008)] and at University of Tokyo [Aikawa et al. New. J. Phys. 11, 055035
\\ ( http://arxiv.org/abs/1009.1696 , 1318kb)
Date: Thu, 9 Sep 2010 07:50:28 GMT (333kb)

Title: Bose-Einstein condensation of 86Sr
Authors: Simon Stellmer, Meng Khoon Tey, Rudolf Grimm, Florian Schreck
Categories: cond-mat.quant-gas
Comments: 4 pages, 3 figures
   We report on the attainment of Bose-Einstein condensation of 86Sr. This
isotope has a scattering length of about +800 a0 and thus suffers from fast
three-body losses. To avoid detrimental atom loss, evaporative cooling is
performed at low densities around 3x10^12 cm^-3 in a large volume optical
dipole trap. We obtain almost pure condensates of 5x10^3 atoms.
\\ ( http://arxiv.org/abs/1009.1701 , 333kb)
Date: Thu, 9 Sep 2010 11:24:21 GMT (4360kb)

Title: Crossover between Kelvin-Helmholtz and counter-superflow instabilities
   in two-component Bose-Einstein condensates
Authors: Naoya Suzuki, Hiromitsu Takeuchi, Kenichi Kasamatsu, Makoto Tsubota,
   Hiroki Saito
Categories: cond-mat.quant-gas
Comments: 10 pages, 9 figures
   Dynamical instabilities at the interface between two Bose--Einstein
condensates that are moving relative to each other are investigated using
mean-field and Bogoliubov analyses. Kelvin--Helmholtz instability is dominant
when the interface thickness is much smaller than the wavelength of the
unstable interface mode, whereas the counter-superflow instability becomes
dominant in the opposite case. These instabilities emerge not only in an
immiscible system but also in a miscible system where an interface is produced
by external potential. Dynamics caused by these instabilities are numerically
demonstrated in rotating trapped condensates.
\\ ( http://arxiv.org/abs/1009.1740 , 4360kb)
Date: Thu, 9 Sep 2010 13:33:09 GMT (5708kb)

Title: Multi-band and nonlinear hopping corrections to the 1D Bose-Fermi
   Hubbard model
Authors: Alexander Mering and Michael Fleischhauer
Categories: cond-mat.quant-gas
Comments: 10 pages, 4 figures, submitted to PRA
   Recent experiments revealed the importance of higher-band effects for the
Mott insulator -- superfluid transition of ultracold bosonic atoms or mixtures
of bosons and fermions in deep optical lattices [Best \emph{et al.}, PRL
\textbf{102}, 030408 (2009); Will \emph{et al.}, Nature \textbf{465}, 197
(2010)]. In the present work, we derive an effective lowest-band Hamiltonian in
1D that generalizes the standard Bose-Fermi-Hubbard model, taking these effects
into account within an adiabatic elimination scheme of virtual transitions to
higher bands. It also accounts for nonlinear corrections of the tunneling
amplitudes mediated by interspecies interactions within the first band only. It
is shown that a correct description of the lattice states in terms of the
bare-lattice Wannier functions rather than approximations such as harmonic
oscillator states is essential. In contrast to self-consistent treatments of
effective lattice wavefunctions, the present approach shows a reduction of the
superfluid phase for both attractive and repulsive interactions between bosons
and fermions.
\\ ( http://arxiv.org/abs/1009.1776 , 5708kb)
Date: Thu, 9 Sep 2010 14:09:30 GMT (44kb)

Title: On the thermodynamics of classical micro-canonical systems
Authors: Maarten Baeten and Jan Naudts
Categories: cond-mat.stat-mech math-ph math.MP
   We study the configurational probability distribution of a mono-atomic gas
with a finite number of particles N in the micro-canonical ensemble. We give
two arguments why the thermodynamic entropy of the configurational subsystem
involves Renyi's entropy function rather than that of Tsallis. The first
argument is that the temperature of the configurational subsystem is equal to
that of the kinetic subsystem. The second argument is that the instability of
the pendulum, which occurs for energies close to the rotation threshold, is
correctly reproduced.
\\ ( http://arxiv.org/abs/1009.1787 , 44kb)

The replacements:

arXiv:1007.4038 (*cross-listing*)
replaced with revised version Thu, 2 Sep 2010 22:40:30 GMT (4194kb)

Title: Robust Mesoscopic Superposition of Strongly Correlated Ultracold Atoms
Authors: David W. Hallwood, Thomas Ernst, Joachim Brand
Categories: quant-ph cond-mat.quant-gas
Comments: 4 pages, 3 figures
\\ ( http://arxiv.org/abs/1007.4038 , 4194kb)
replaced with revised version Fri, 3 Sep 2010 07:16:11 GMT (1141kb,D)

Title: Phase separation of binary condensates in harmonic and lattice
Authors: S. Gautam and D. Angom
Categories: cond-mat.quant-gas
Comments: 12 pages, 9 figures, typos removed, title changed
\\ ( http://arxiv.org/abs/1008.4732 , 1141kb)
replaced with revised version Fri, 3 Sep 2010 12:09:31 GMT (766kb)

Title: Rotons in a hybrid Bose-Fermi system
Authors: I.A. Shelykh, T. Taylor and A.V. Kavokin
Categories: cond-mat.quant-gas
Comments: Revised version with parameters of realistic GaAs double quantum
   well, accepted for publication in Phys. Rev. Lett
\\ ( http://arxiv.org/abs/1007.2891 , 766kb)
replaced with revised version Mon, 6 Sep 2010 08:13:45 GMT (39kb)

Title: Bose-Fermi-Hubbard model at finite temperature
Authors: T S Mysakovych
Categories: cond-mat.other
Journal-ref: J. Phys.: Condens. Matter 22 (2010) 355601
\\ ( http://arxiv.org/abs/1004.0304 , 39kb)
replaced with revised version Mon, 6 Sep 2010 08:50:24 GMT (683kb,D)

Title: Manipulation of coherent atom waves using accelerated two-dimensional
   optical lattices
Authors: Wei-Chih Ting, Dian-Jiun Han, and Shin-Tza Wu
Categories: cond-mat.quant-gas
Comments: Figures with low resolution; high quality ones can be supplied on
Journal-ref: New J Phys, 12, 083059 (2010)
DOI: 10.1088/1367-2630/12/8/083059
\\ ( http://arxiv.org/abs/1005.1138 , 683kb)
arXiv:1008.3406 (*cross-listing*)
replaced with revised version Mon, 6 Sep 2010 11:23:07 GMT (700kb,D)

Title: Quantum phase diagram of the integrable p_x+ip_y fermionic superfluid
Authors: Stefan M.A. Rombouts, Jorge Dukelsky, Gerardo Ortiz
Categories: cond-mat.quant-gas quant-ph
Comments: 12 figures
\\ ( http://arxiv.org/abs/1008.3406 , 700kb)
replaced with revised version Mon, 6 Sep 2010 19:13:20 GMT (44kb)

Title: Decoherence and damping in ideal gases
Authors: Janos Polonyi
Categories: quant-ph cond-mat.stat-mech
Comments: final version, to appear in Europhysical Letter
\\ ( http://arxiv.org/abs/1001.1803 , 44kb)
replaced with revised version Wed, 8 Sep 2010 15:05:26 GMT (151kb,D)

Title: Radio Frequency Association of Efimov Trimers
Authors: Thomas Lompe, Timo B. Ottenstein, Friedhelm Serwane, Andre N. Wenz,
   Gerhard Z\"urn and Selim Jochim
Categories: cond-mat.quant-gas
Comments: 15 pages, 6 figures
\\ ( http://arxiv.org/abs/1006.2241 , 151kb)
replaced with revised version Wed, 8 Sep 2010 15:33:09 GMT (123kb)

Title: Klein tunneling and Dirac potentials in trapped ions
Authors: J. Casanova, J. J. Garcia-Ripoll, R. Gerritsma, C. F. Roos, and E.
Categories: quant-ph cond-mat.mes-hall cond-mat.quant-gas hep-th
Comments: 4 pages, 3 figures, minor changes
Journal-ref: Phys. Rev. A. 82, 020101(R) (2010)
\\ ( http://arxiv.org/abs/1004.5400 , 123kb)
replaced with revised version Wed, 8 Sep 2010 17:14:30 GMT (47kb)

Title: Magnetic phases of spin-3/2 fermions on a spatially anisotropic square
Authors: A. K. Kolezhuk and T. Vekua
Categories: cond-mat.quant-gas
Comments: 10 Revtex pages, 5 figures; (v2) corrected the last paragraph in
   Appendix B and some typos
\\ ( http://arxiv.org/abs/1008.0598 , 47kb)
replaced with revised version Wed, 8 Sep 2010 19:25:16 GMT (754kb)

Title: Phase-space description of the magneto-optical trap
Authors: Rudy Romain (PhLAM), Daniel Hennequin (PhLAM), Philippe Verkerk
Categories: physics.atom-ph
\\ ( http://arxiv.org/abs/1007.5380 , 754kb)
replaced with revised version Thu, 9 Sep 2010 16:42:56 GMT (1212kb)

Title: Dynamics of quantum phase transitions in Dicke and Lipkin-Meshkov-Glick
Authors: A.P. Itin, P. T\"orm\"a
Categories: cond-mat.stat-mech cond-mat.quant-gas
Comments: 21 pages, 33 figures; Comments to ver.3: major revision, added
   Lipkin-Meshkov-Glick model and Dicke model with counterrotating terms
\\ ( http://arxiv.org/abs/0901.4778 , 1212kb)
replaced with revised version Thu, 9 Sep 2010 17:35:18 GMT (43kb)

Title: Dynamical mean field solution of the Bose-Hubbard model
Authors: Peter Anders, Emanuel Gull, Lode Pollet, Matthias Troyer, Philipp
Categories: cond-mat.str-el cond-mat.quant-gas
Comments: 10 pages, 3 figures. includes supplementary material
Journal-ref: Phys. Rev. Lett. 105, 096402 (2010)
\\ ( http://arxiv.org/abs/1004.0510 , 43kb)
arXiv:0912.2943 (*cross-listing*)
replaced with revised version Thu, 9 Sep 2010 18:38:29 GMT (1452kb)

Title: Interaction of a propagating guided matter wave with a localized
Authors: Giovanni Luca Gattobigio (LCAR), Antoine Couvert (LCAR), Bertrand
   Georgeot (LPT), David Gu\'ery-Odelin (LCAR)
Categories: cond-mat.other cond-mat.quant-gas quant-ph
Journal-ref: New Journal of Physics 12 (2010) 085013
DOI: 10.1088/1367-2630/12/8/085013
\\ ( http://arxiv.org/abs/0912.2943 , 1452kb)
replaced with revised version Thu, 9 Sep 2010 18:55:15 GMT (58kb)

Title: Time-Dependent Mean Field Theory for Quench Dynamics in correlated
   electron systems
Authors: Marco Schir\'o, Michele Fabrizio
Categories: cond-mat.str-el cond-mat.quant-gas
Comments: 4 pages, 2 figures, published version
Journal-ref: Phys. Rev. Lett. 105, 076401 (2010)
DOI: 10.1103/PhysRevLett.105.076401
\\ ( http://arxiv.org/abs/1005.0992 , 58kb)

Till next time,

Dr M. J. Davis,                      Associate Professor in Physics
School of Mathematics and Physics,   ph  : +61 7 334 69824
The University of Queensland,        fax : +61 7 336 51242
Brisbane, QLD 4072,                  mdavis_at_physics.uq.edu.au
Australia.                           www.physics.uq.edu.au/people/mdavis/
Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org
Legal stuff: Unless stated otherwise, this e-mail represents only the
views of the sender and not the views of the University of Queensland
Matts-arxiv mailing list
Received on Thu Nov 04 2010 - 10:05:09 EST

This archive was generated by hypermail 2.2.0 : Thu Nov 04 2010 - 10:05:27 EST