# Matt's arXiv selection: week ending 27 June 2008

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Sun, 29 Jun 2008 22:46:10 +1000

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

I've finally done it! You're back up to date: there are no emails from
arXiv.org waiting for me to go through.

This week there were 27 preprints and 11 replacements:

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arXiv:0806.3395
Date: Fri, 20 Jun 2008 14:01:19 GMT (203kb)

Title: Creation and detection of a mesoscopic gas in a non-local quantum
superposition
Authors: Christoph Weiss (LKB - Lhomond), Yvan Castin (LKB - Lhomond)
Categories: cond-mat.other
\\
We investigate the scattering of a quantum matter wave soliton on a barrier
in a one dimensional geometry and we show that it can lead to mesoscopic
Schr\"odinger cat states, where the atomic gas is in a coherent superposition
of being in the half-space to the left of the barrier and being in the
half-space to the right of the barrier. We propose an interferometric method to
reveal the coherent nature of this superposition and we discuss in details the
experimental feasibility.
\\ ( http://arxiv.org/abs/0806.3395 , 203kb)
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arXiv:0806.3402
Date: Fri, 20 Jun 2008 14:20:29 GMT (281kb)

Title: Ionization in a frozen Rydberg gas with attractive or repulsive
potentials
Authors: Matthieu Viteau (LAC), Amodsen Chotia (LAC), Daniel Comparat (LAC),
Duncan A. Tate (LAC), Thomas F. Gallagher (LAC), Pierre Pillet (LAC)
Categories: physics.atom-ph
\\
We report clear evidence of the role of dipole-dipole interaction in Penning
ionization of Rydberg atoms, leading to the formation of an ultracold plasma.
Penning ionization of np Rydberg Cesium atoms is prevented for states with in n
< 42, which correspond to a repulsive potential, but it does not occur for n
larger than 42, corresponding to an attractive potential. Blackbody radiation
is mostly responsible for the background and initial ionization, although
ion-Rydberg collisions and population transfer due to limited superradiance may
have to be considered.
\\ ( http://arxiv.org/abs/0806.3402 , 281kb)
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arXiv:0806.3780
Date: Mon, 23 Jun 2008 21:44:28 GMT (171kb)

Title: Cold Fermionic Atoms in Traps -- Pairing versus Hund's Rule
Authors: M. Rontani, J. Armstrong, Y. Yu, S. {\AA}berg, S. M. Reimann
Categories: cond-mat.mes-hall
Comments: RevTeX 4.0, 4 pages, 4 colour postscript figures
\\
The microscopic properties of a finite many-body system of few interacting
cold fermionic atoms confined in a harmonic trap are studied by numerical
diagonalization. For repulsive interactions, a strong shell structure
dominates, with Hund's rule acting at its extreme for the mid-shell
configurations. In the attractive case, odd-even oscillations due to pairing
occur simultaneously with deformations in the internal structure of the ground
states, as seen from pair correlation functions.
\\ ( http://arxiv.org/abs/0806.3780 , 171kb)
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arXiv:0806.3806
Date: Tue, 24 Jun 2008 04:33:54 GMT (655kb)

Title: Exactly chaotic shock waves of a Bose-Einstein condensate
Authors: Wenhua Hai, Qianquan Zhu, Shiguang Rong
Categories: cond-mat.other nlin.CD quant-ph
\\
Classical Smale-horseshoe chaos appeared in a perimetrically driven Duffing
system with the attractive or expulsive parabolic potential and the
nonlinearity. It is demonstrated that such a well-known chaos certainly exists
in the time evolution of one-dimensional (1D) Bose-Einstein condensate (BEC)
experiencing the time-periodic harmonic or inverted-harmonic potential. A
formally exact solution of the time-dependent Gross-Pitaevskii equation (GPE)
is constructed, which describes the matter shock wave with chaotic or periodic
amplitude and phase. When the periodic driving is switched off and the number
of condensed atoms is conserved, the exact shock wave alternately collapses and
grows for the harmonic trapping or propagates with exponentially increased
shock-front speed for the antitrapping. The result suggests an experimental
method for preparing the exponentially accelerated shock waves.
\\ ( http://arxiv.org/abs/0806.3806 , 655kb)
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arXiv:0806.3840
Date: Tue, 24 Jun 2008 09:43:40 GMT (631kb)

Title: Spin-vortex nucleation in a Bose-Einstein condensate by a spin-dependent
rotating trap
Authors: Hiroki Chiba and Hiroki Saito
Categories: cond-mat.other
\\
A method to produce a spin-dependent rotating potential using near-resonant
circularly polarized laser beams is proposed. It is shown that half-quantum
vortices are nucleated in a spinor Bose-Einstein condensate with an
antiferromagnetic interaction. In contrast to the vortex nucleation in a scalar
BEC, the spin-vortex nucleation occurs at a low rotation frequency ($\simeq 0.1 \omega_\perp$ with $\omega_\perp$ being the radial trap frequency) in a short
nucleation time $\simeq 50$ ms without dissipation. A method for nondestructive
measurement of half-quantum vortices is discussed.
\\ ( http://arxiv.org/abs/0806.3840 , 631kb)
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arXiv:0806.3877
Date: Tue, 24 Jun 2008 12:49:56 GMT (588kb,D)

Title: Optimizing number squeezing when splitting a mesoscopic condensate
Authors: Julian Grond, Joerg Schmiedmayer, Ulrich Hohenester
Categories: cond-mat.other
\\
We optimize number squeezing when splitting a mesoscopic condensate. A
combination of optimal control theory and the multiconfigurational
time-dependent Hartree method for bosons allowed us to identify a form of the
splitting ramp which drastically outperforms the adiabatic splitting. Our
results can be interpreted in terms of a generic two-mode model mapped onto a
parametric harmonic oscillator. This optimal route to squeezing paves the way
to atom interferometry close to the Heisenberg limit.
\\ ( http://arxiv.org/abs/0806.3877 , 588kb)
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arXiv:0806.3948
Date: Tue, 24 Jun 2008 18:28:03 GMT (119kb)

Title: How the effective boson-boson interaction works in Bose-Fermi mixtures
in periodic geometries
Authors: Giovanni Mazzarella
Categories: cond-mat.other
\\
We study mixtures of spinless bosons and not spin-polarized fermions loaded
in two dimensional optical lattices. We approach the problem of the ground
state stability within the framework of the linear response theory; by the mean
of an iterative procedure, we are able to obtain a relation for the dependence
of boson-boson effective interaction on the absolute temperature of the sample.
Proceeding from such a formula, we write down analyitical expressions for
Supersolid (SS) and Phase Separation (PS) transition temperatures, and plot the
phase diagrams.
\\ ( http://arxiv.org/abs/0806.3948 , 119kb)
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arXiv:0806.3754
Date: Tue, 24 Jun 2008 13:34:12 GMT (693kb)

Title: Quantum critical behavior in strongly interacting Rydberg gases
Authors: Hendrik Weimer, Robert L\"ow, Tilman Pfau, Hans Peter B\"uchler
Categories: quant-ph
\\
We study the appearance of correlated many-body phenomena in an ensemble of
atoms driven resonantly into a strongly interacting Rydberg state. The ground
state of the Hamiltonian describing the driven system exhibits a second order
quantum phase transition. We derive the critical theory for the quantum phase
transition and show that it describes the properties of the driven Rydberg
system in the saturated regime. We find that the suppression of Rydberg
excitations known as blockade phenomena exhibits an algebraic scaling law with
a universal exponent.
\\ ( http://arxiv.org/abs/0806.3754 , 693kb)
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arXiv:0806.3842
Date: Tue, 24 Jun 2008 09:33:22 GMT (443kb)

Title: Quantum Ratchet Accelerator without a Bichromatic Lattice Potential
Authors: Jiao Wang and Jiangbin Gong
Categories: quant-ph
Comments: 9 pages, 6 figures, submitted to Phys. Rev. E
\\
In a quantum ratchet accelerator system, a linearly increasing directed
current can be dynamically generated without using a biased field. Generic
quantum ratchet acceleration with full classical chaos [Gong and Brumer, Phys.
Rev. Lett. 97, 240602 (2006)] constitutes a new element of quantum chaos and an
interesting violation of a sum rule of classical ratchet transport. Here we
propose a simple quantum ratchet accelerator model that can also generate
linearly increasing quantum current with full classical chaos. This new model
does not require a bichromatic lattice potential. It is based on a variant of
an on-resonance kicked-rotor system, periodically kicked by two optical lattice
potentials of the same lattice constant, but with unequal amplitudes and a
fixed phase shift between them. The dependence of the ratchet current
acceleration rate on the system parameters is studied in detail. The cold-atom
version of our new quantum ratchet accelerator model should be realizable by
introducing slight modifications to current cold-atom experiments.
\\ ( http://arxiv.org/abs/0806.3842 , 443kb)
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arXiv:0806.3909
Date: Tue, 24 Jun 2008 17:10:52 GMT (2154kb)

Title: Blue-detuned evanescent field surface traps for neutral atoms based on
mode interference in ultra-thin optical fibres
Authors: G. Sague, A. Baade and A. Rauschenbeutel
Categories: quant-ph
\\
We present and analyze a novel concept for blue-detuned evanescent field
surface traps for cold neutral atoms based on two-mode interference in
ultra-thin optical fibres. When two or more transverse modes with the same
frequency co-propagate in the fibre, their different phase velocities cause a
stationary interference pattern to establish. Intensity minima of the
evanescent field at any distance from the fibre surface can be created and an
array of optical microtraps can thus be obtained in the evanescent field. We
discuss three possible combinations of the lowest order modes, yielding traps
at one to two hundred nanometres from the fibre surface which, using a few ten
milliwatts of trapping laser power, have a depth on the order of 1 mK for
caesium atoms and a trapping lifetime exceeding 100 seconds. The resulting
trapping geometry is of particular interest because atoms in such microtrap
arrays will be coupled to any additional field propagating in the fibre via the
evanescent field, thereby realising ensembles of fibre-coupled atoms.
\\ ( http://arxiv.org/abs/0806.3909 , 2154kb)
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arXiv:0806.3829
Date: Tue, 24 Jun 2008 11:56:17 GMT (302kb)

Title: Optical pumping and vibrational cooling of molecules
Authors: Matthieu Viteau (LAC), Amodsen Chotia (LAC), Maria Allegrini (LAC,
CNISM), Nadia Bouloufa (LAC), Olivier Dulieu (LAC), Daniel Comparat (LAC),
Pierre Pillet (LAC)
Categories: physics.atom-ph
\\
The methods producing cold molecules from cold atoms tend to leave molecular
ensembles with substantial residual internal energy. For instance, Cs2
molecules initially formed via photoassociation of cold Cs atoms are in several
vibrational levels, v, of the electronic ground state. Here we apply a
broadband femtosecond laser that redistributes the vibrational population in
the ground state via a few electronic excitation - spontaneous emission cycles.
The laser pulses are shaped to remove the excitation frequency band of the v =
0 level, preventing re-excitation from that state. We observe a fast and
efficient accumulation, about 70% of the initially detected molecules, in the
lowest vibrational level, v = 0, of the singlet electronic state. The validity
of this incoherent depopulation pumping method is very general and opens
exciting prospects for laser cooling and manipulation of molecules.
\\ ( http://arxiv.org/abs/0806.3829 , 302kb)
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arXiv:0806.3839
Date: Tue, 24 Jun 2008 09:39:27 GMT (22kb)

Title: N-body Efimov states of trapped bosons
Authors: M. Th{\o}gersen, D. V. Fedorov, A. S. Jensen
Categories: physics.atom-ph
\\
We demonstrate the possibility of existence of meta-stable N-body Efimov
states in trapped Bose systems with large scattering length. We calculate
spectra of trapped systems of N=3,4,5,6, and 7 bosons using a stochastic
variational method with a restricted correlated Gaussian basis. For each system
the calculations reveal a series of Efimov states where the energy and the
r.m.s. radius exhibit the characteristic exponential dependence upon the state
number. We also estimate the contribution of these states to the recombination
rate of Bose-Einstein condensates.
\\ ( http://arxiv.org/abs/0806.3839 , 22kb)
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arXiv:0806.3894
Date: Tue, 24 Jun 2008 15:48:14 GMT (645kb,D)

Title: Fractional resonances in the atom-optical delta-kicked accelerator
Authors: M. Saunders, P.L. Halkyard, S.A. Gardiner, and K.J. Challis
Categories: physics.atom-ph
\\
We consider resonant dynamics in a dilute atomic gas falling under gravity
through a periodically pulsed standing-wave laser field. Our numerical
calculations are based on a Monte Carlo method for an incoherent mixture of
noninteracting plane waves, and show that quantum resonances are highly
sensitive to the relative acceleration between the atomic gas and the pulsed
optical standing wave. For particular values of the atomic acceleration, we
observe fractional resonances. We investigate the effect of the initial atomic
momentum width on the fractional resonances, and quantify the sensitivity of
fractional resonances to thermal effects.
\\ ( http://arxiv.org/abs/0806.3894 , 645kb)
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arXiv:0806.3490
Date: Mon, 23 Jun 2008 18:14:36 GMT (406kb)

Title: Controlled quantum stirring of Bose-Einstein condensates
Authors: Moritz Hiller, Tsampikos Kottos, Doron Cohen
Categories: cond-mat.other
\\
By cyclic adiabatic change of two control parameters of an optical trap one
can induce a circulating current of condensed bosons. The amount of particles
that are transported per period depends on the "radius" of the cycle, and this
dependence can be utilized in order to probe the interatomic interactions. For
strong repulsive interaction the current can be regarded as arising from a
sequence of Landau-Zener crossings. For weaker interaction one observes either
gradual or coherent mega crossings, while for attractive interaction the
particles are glued together and behave like a classical ball. For the analysis
we use the Kubo approach to quantum pumping with the associated Dirac monopoles
picture of parameter space.
\\ ( http://arxiv.org/abs/0806.3490 , 406kb)
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arXiv:0806.3608
Date: Mon, 23 Jun 2008 03:52:35 GMT (536kb)

Title: Solitons in Bose-Einstein Condensates with time-dependent atomic
scattering length in an expulsive parabolic and complex potential
Authors: Biao Li, Xiao-Fei Zhang, Yu-Qi Li, Yong Chen, W. M. Liu
Categories: cond-mat.other
\\
We present two families of analytical solutions of the one-dimensional
nonlinear Schr\"{o}dinger equation which describe the dynamics of bright and
dark solitons in Bose-Einstein condensates (BECs) with the time-dependent
interatomic interaction in an expulsive parabolic and complex potential. We
also demonstrate that the lifetime of both a bright soliton and a dark soliton
in BECs can be extended by reducing both the ratio of the axial oscillation
frequency to radial oscillation frequency and the loss of atoms. It is
interested that a train of bright solitons may be excited with a strong enough
background. An experimental protocol is further designed for observing this
phenomenon.
\\ ( http://arxiv.org/abs/0806.3608 , 536kb)
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arXiv:0806.3464
Date: Fri, 20 Jun 2008 20:19:30 GMT (86kb)

Title: Photoassociation spectroscopy of a Spin-1 Bose-Einstein condensate
Authors: C.D. Hamley, E.M. Bookjans, G. Behin-Aein, P. Ahmadi, and M.S. Chapman
Categories: physics.atom-ph
\\
We report on the high resolution photoassociation spectroscopy of a $^{87}$Rb
spin-1 Bose-Einstein condensate to the $1_\mathrm{g} (P_{3/2}) v = 152$ excited
molecular states. We demonstrate the use of spin dependent photoassociation to
experimentally identify the molecular states and their corresponding initial
scattering channel. These identifications are in excellent agreement with the
eigenvalues of a hyperfine-rotational Hamiltonian. Using the observed spectra
we estimate the change in scattering length and identify photoassociation laser
light frequency ranges that maximize the change in the spin-dependent
mean-field interaction energy.
\\ ( http://arxiv.org/abs/0806.3464 , 86kb)
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arXiv:0806.3466
Date: Fri, 20 Jun 2008 20:28:18 GMT (861kb)

Title: Dark dynamic acousto-optic ring lattices for ultracold atoms
Authors: N. Houston, E. Riis, A. S. Arnold
Categories: physics.optics physics.atom-ph
\\
We demonstrate the optical generation of dynamic dark optical ring lattices,
which do not require Laguerre-Gauss beams, large optical coherence lengths or
interferometric stability. Simple control signals lead to spatial modulation
and reproducible rotation, offering manifold possibilities for complex dynamic
ring lattices. In conjunction with a magnetic trap, these scanned 2D intensity
distributions from a single laser beam will enable precision trapping and
manipulation of ultracold species using blue-detuned light. The technique is
ideal for azimuthal ratchet, Mott insulator and persistent current experiments
with quantum degenerate gases.
\\ ( http://arxiv.org/abs/0806.3466 , 861kb)
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arXiv:0806.3991
Date: Tue, 24 Jun 2008 21:17:21 GMT (129kb)

Title: Low-energy resonances and bound states of aligned bosonic and fermionic
dipoles
Authors: K. Kanjilal and D. Blume
Categories: cond-mat.other
\\
The low-energy scattering properties of two aligned identical bosonic and
identical fermionic dipoles are analyzed. Generalized scattering lengths are
determined as functions of the dipole moment and the scattering energy. Near
resonance, where a new bound state is being pulled in, all non-vanishing
generalized scattering lengths diverge, with the $a_{00}$ and $a_{11}$
scattering lengths being dominant for identical bosons and identical fermions,
respectively, near both broad and narrow resonances. Implications for the
energy spectrum and the eigenfunctions of trapped two-dipole systems and for
pseudo-potential treatments are discussed.
\\ ( http://arxiv.org/abs/0806.3991 , 129kb)
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arXiv:0806.4106
Date: Wed, 25 Jun 2008 19:20:16 GMT (24kb)

Title: Formation of vortices in a dense Bose-Einstein condensate
Authors: V.P. Barros, Ch. Moseley, A. Gammal, K. Ziegler
Categories: cond-mat.other
\\
A relaxation method is employed to study a rotating dense Bose-Einstein
condensate beyond Thomas-Fermi approximation. We use a slave-boson model to
describe the strongly interacting condensate and derive a generalized
non-linear Schr\"odinger equation with kinetic term for the rotating
condensate. In comparison with previous calculations, based on Thomas-Fermi
approximation, significant improvements are found in regions, where the
condensate in a trap potential is not smooth. The critical angular velocity of
the vortex formation is higher than in the Thomas-Fermi prediction.
\\ ( http://arxiv.org/abs/0806.4106 , 24kb)
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arXiv:0806.4002
Date: Wed, 25 Jun 2008 15:46:47 GMT (768kb)

Title: Quantum theory of ultracold atom-ion collisions
Authors: Zbigniew Idziaszek, Tommaso Calarco, Paul S. Julienne, and Andrea
Simoni
Categories: physics.atom-ph
\\
We study atom-ion scattering in the ultracold regime. To this aim, an
analytical model based on the multichannel quantum defect formalism is
developed and compared to close-coupled numerical calculations. We investigate
the occurrence of magnetic Feshbach resonances focusing on the specific 40Ca+ -
Na system. The presence of several resonances at experimentally accessible
magnetic fields should allow the atom-ion interaction to be precisely tuned. A
fully quantum-mechanical study of charge exchange processes shows that
charge-exchange rates should remain small even in the presence of resonance
effects. Most of our results can be cast in a system-independent form and are
important for the realization of the charge-neutral ultracold systems.
\\ ( http://arxiv.org/abs/0806.4002 , 768kb)
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arXiv:0806.4192
Date: Wed, 25 Jun 2008 20:21:22 GMT (73kb)

Title: Theory of spin nematic to spin-Peierls quantum phase transition in
ultracold spin-1 atoms in optical lattices
Authors: Christoph M. Puetter, Michael J. Lawler, Hae-Young Kee
Categories: cond-mat.str-el
\\
We present a theory of the anisotropy tuned quantum phase transition between
spin nematic and spin-Peierls phases in S=1 systems with significant
bi-quadratic exchange interactions. Based on quantum Monte Carlo studies on
finite size systems, [K. Harada et al., J. Phys. Soc. Jpn. 76, 013703 (2007)]
it has been proposed that this phase transition is second order with new
deconfined fractional excitations that are absent in either of the two phases
[T. Grover and T. Senthil, Phys. Rev. Lett. 98, 247202 (2007)]. The possibility
of a weak first order transition, however, cannot be ruled out. To elucidate
the nature of the transition, we construct a large-N SO(3N) model for this
phase transition and find in the $N\to\infty$ limit that the transition is
generically of first order. Furthermore, in the extreme anisotropic
1-dimensional limit, we find no sign of a disordered spin nematic phase, as
originally suggested by Chubukov [A. V. Chubukov, Phys. Rev. B, 43, 3337
(1990)] based on a spin-1 bond operator (two-site cluster) approach.
Predictions for $^{23}$Na atoms trapped in an optical lattice, where this
quantum phase transition naturally arises, are discussed.
\\ ( http://arxiv.org/abs/0806.4192 , 73kb)
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arXiv:0806.4283
Date: Thu, 26 Jun 2008 18:01:30 GMT (58kb)

Title: Synchronization and Dephasing of Many-Body States in Optical Lattices
Authors: M. B. Hastings and L. S. Levitov
Categories: cond-mat.str-el
\\
We introduce an approach to describe quantum-coherent evolution of a system
of cold atoms in an optical lattice triggered by a change in superlattice
potential. Using a time-dependent mean field description, we map the problem to
a strong coupling limit of previously studied time-dependent BCS model. We
compare the mean field dynamics to a simulation using light-cone methods and
find reasonable agreement for numerically accessible times. The mean field
model is integrable, and gives rise to a rich behavior, in particular to beats
and recurrences in the order parameter, as well as singularities in the
momentum distribution, directly measureable in cold atom experiment.
\\ ( http://arxiv.org/abs/0806.4283 , 58kb)
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arXiv:0806.4310
Date: Thu, 26 Jun 2008 13:10:05 GMT (125kb)

Title: Strong dissipation inhibits losses and induces correlations in cold
molecular gases
Authors: N. Syassen, D. M. Bauer, M. Lettner, T. Volz, D. Dietze, J. J.
Garcia-Ripoll, J. I. Cirac, G. Rempe, S. D\"urr
Categories: cond-mat.other cond-mat.str-el
Journal-ref: Science 320, 1329 (2008)
DOI: 10.1126/science.1155309
\\
Atomic quantum gases in the strong-correlation regime offer unique
possibilities to explore a variety of many-body quantum phenomena. Reaching
this regime has usually required both strong elastic and weak inelastic
interactions, as the latter produce losses. We show that strong inelastic
collisions can actually inhibit particle losses and drive a system into a
strongly-correlated regime. Studying the dynamics of ultracold molecules in an
optical lattice confined to one dimension, we show that the particle loss rate
is reduced by a factor of 10. Adding a lattice along the one dimension
increases the reduction to a factor of 2000. Our results open up the
possibility to observe exotic quantum many-body phenomena with systems that
suffer from strong inelastic collisions.
\\ ( http://arxiv.org/abs/0806.4310 , 125kb)
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arXiv:0806.4325
Date: Thu, 26 Jun 2008 15:33:51 GMT (131kb)

Title: Harmonic Stability Analysis of the 2D Square and Hexagonal Bravais
Lattices for a Finite--Ranged Repulsive Pair Potential. Consequence for a 2D
System of Ultracold Composite Bosons
Authors: D.J. Papoular
Categories: cond-mat.other
\\
We consider a classical, two-dimensional system of identical particles which
interact via a finite-ranged, repulsive pair potential. We assume that the
system is in a crystalline phase. We calculate the normal vibrational modes of
a two-dimensional square Bravais lattice, first analytically within the
nearest-neighbour approximation, and then numerically, relaxing the preceding
hypothesis. We show that, in the harmonic approximation, the excitation of a
transverse vibrational mode leads to the breakdown of the square lattice. We
next study the case of the hexagonal Bravais lattice and we show that it can be
stable with respect to lattice vibrations. We give a criterion determining
whether or not it is stable in the nearest-neighbour approximation. Finally, we
apply our results to a two-dimensional system of composite bosons and infer
that the crystalline phase of such a system, if it exists, corresponds to a
hexagonal lattice.
\\ ( http://arxiv.org/abs/0806.4325 , 131kb)
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arXiv:0806.4378
Date: Thu, 26 Jun 2008 19:42:06 GMT (11kb)

Title: Vortex pseudomomentum and dissipation in a superfluid vortex lattice
Authors: H. M. Cataldo
Categories: cond-mat.stat-mech cond-mat.other
Journal-ref: J. Phys. A: Math. Theor. 41 (2008) 295501 (9pp)
DOI: 10.1088/1751-8113/41/29/295501
\\
We propose an alternative approach to the dissipative vortex dynamics
occurring in a superfluid vortex lattice at finite temperatures. Focusing upon
the pseudomomentum of a vortex and its surrounding quasiparticles, we derive an
equation of motion which, in spite of yielding the same evolution as the usual
one for massless vortices, does not involve the vortex mass. This picture could
provide further insights into the controversy about the nature of the vortex
mass.
\\ ( http://arxiv.org/abs/0806.4378 , 11kb)
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arXiv:0806.4258
Date: Thu, 26 Jun 2008 07:54:34 GMT (1234kb)

Title: Photon echoes generated by reversing magnetic field gradients in a
rubidium vapour
Authors: G. H\'etet, M. Hosseini, B. Sparkes, D. Oblak, P. K. Lam and B. C.
Buchler
Categories: quant-ph
\\
We propose a photon echo quantum memory scheme using detuned Raman coupling
to long lived ground states. In contrast to previous 3-level schemes based on
controlled reversible inhomogeneous broadening that use sequences of
$\pi$-pulses, the scheme does not require accurate control of the coupling
dynamics to the ground states. We present a proof of principle experimental
realization of our proposal using rubidium atoms in a warm vapour cell. The
Raman resonance line is broadened using a magnetic field that varies linearly
along the direction of light propagation. Inverting the magnetic field gradient
rephases the atomic dipoles and re-emits the light pulse in the forward
direction.
\\ ( http://arxiv.org/abs/0806.4258 , 1234kb)
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arXiv:0806.4337
Date: Thu, 26 Jun 2008 15:17:37 GMT (1776kb)

Title: Low-density, one dimensional quantum gases in the presence of a
localised attractive potential
Authors: J. Goold, D. O Donoghue and Th. Busch
Categories: quant-ph
\\
We investigate low-density, quantum-degenerate gases in the presence of a
localised attractive potential in the centre of a one-dimensional harmonic
trap.The attractive potential is modelled using a parameterised delta-function,
allowing us to determine all single particle eigenfunctions analytically. From
these we calculate the ground state many-body properties for a system of
spin-polarised fermions and, using the Bose-Fermi mapping theorem, extend the
results to strongly interacting bosonic systems. We discuss the single particle
densities, the pair correlation functions, the reduced single particle density
matrices and the momentum distributions as a function of particle number and
strength of the attractive point potential. As an important experimental
observable, we place special emphasis on spatial coherence properties of such
samples.
\\ ( http://arxiv.org/abs/0806.4337 , 1776kb)
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The replacements:

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arXiv:0712.2256
replaced with revised version Thu, 19 Jun 2008 22:45:18 GMT (160kb)

Title: New type of Bose-Einstein condensation of cold atoms with effective
spin-orbit interactions
Authors: Tudor Stanescu and Victor Galitski
Categories: cond-mat.other cond-mat.stat-mech quant-ph
Comments: 4 pages, 2 color figures (new Fig. 2)
\\ ( http://arxiv.org/abs/0712.2256 , 160kb)
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arXiv:0804.2705
replaced with revised version Thu, 19 Jun 2008 23:27:14 GMT (304kb)

Title: Phase Separation in Bose-Fermi-Fermi Mixtures as a Probe of Fermi
Superfluidity
Authors: S. G. Bhongale and Han Pu
Categories: cond-mat.stat-mech cond-mat.supr-con quant-ph
\\ ( http://arxiv.org/abs/0804.2705 , 304kb)
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arXiv:0712.2571
replaced with revised version Tue, 24 Jun 2008 10:24:37 GMT (559kb,D)

Title: Ultracold atomic gas in non-Abelian "magnetic" fields: the quantum Hall
effect supremacy
Authors: N. Goldman, A. Kubasiak, P. Gaspard and M. Lewenstein
Categories: cond-mat.mes-hall
\\ ( http://arxiv.org/abs/0712.2571 , 559kb)
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arXiv:0803.0507
replaced with revised version Tue, 24 Jun 2008 12:45:36 GMT (851kb,D)

Title: Numerical observation of Hawking radiation from acoustic black holes in
atomic Bose-Einstein condensates
Authors: Iacopo Carusotto, Serena Fagnocchi, Alessio Recati, Roberto Balbinot,
Alessandro Fabbri
Categories: cond-mat.other gr-qc hep-th
Comments: Version 2 with enlarged text and several new figures
\\ ( http://arxiv.org/abs/0803.0507 , 851kb)
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arXiv:0805.2708
replaced with revised version Tue, 24 Jun 2008 11:08:35 GMT (405kb,D)

Title: Modulation transfer spectroscopy in atomic rubidium
Authors: D. J. McCarron, S. A. King and S. L. Cornish
Categories: physics.atom-ph
\\ ( http://arxiv.org/abs/0805.2708 , 405kb)
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arXiv:0804.0355
replaced with revised version Mon, 23 Jun 2008 09:48:25 GMT (20kb)

Title: Pair-Breaking in Rotating Fermi Gases
Authors: Michael Urban and Peter Schuck
Categories: cond-mat.other
Comments: 4 pages, 2 figures; v2: discussion clarified, typos corrected, one
\\ ( http://arxiv.org/abs/0804.0355 , 20kb)
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arXiv:0805.2708
replaced with revised version Mon, 23 Jun 2008 14:57:31 GMT (452kb)

Title: Modulation transfer spectroscopy in atomic rubidium
Authors: D. J. McCarron, S. A. King and S. L. Cornish
Categories: physics.atom-ph
\\ ( http://arxiv.org/abs/0805.2708 , 452kb)
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arXiv:0804.1547
replaced with revised version Wed, 25 Jun 2008 01:02:19 GMT (572kb)

Title: Supersolid state of ultracold fermions in an optical lattice
Authors: Akihisa Koga, Takuji Higashiyama, Kensuke Inaba, Seiichiro Suga, and
Norio Kawakami
Categories: cond-mat.supr-con
Journal-ref: J. Phys. Soc. Jpn. 77, 073602 (2008)
DOI: 10.1143/JPSJ.77.073602
\\ ( http://arxiv.org/abs/0804.1547 , 572kb)
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arXiv:0802.4055
replaced with revised version Wed, 25 Jun 2008 15:49:33 GMT (264kb)

Title: Bifurcations, order, and chaos in the Bose-Einstein condensation of
dipolar gases
Authors: Patrick K\"oberle, Holger Cartarius, Toma\v{z} Fab\v{c}i\v{c}, J\"org
Main, G\"unter Wunner
Categories: quant-ph nlin.CD
\\ ( http://arxiv.org/abs/0802.4055 , 264kb)
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arXiv:0710.1848
replaced with revised version Thu, 26 Jun 2008 10:15:10 GMT (355kb,D)

Title: Long wavelength spin dynamics of ferromagnetic condensates
Authors: Austen Lamacraft
Categories: cond-mat.other cond-mat.supr-con
experiment of Vengalattore et. al. (Phys. Rev. Lett. 100, 170403, (2008))
Journal-ref: Phys. Rev. A 77, 063622 (2008)
\\ ( http://arxiv.org/abs/0710.1848 , 355kb)
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arXiv:0803.1889
replaced with revised version Thu, 26 Jun 2008 09:38:10 GMT (260kb)

Title: Atom-Pair Tunneling in Optical Lattices
Authors: J.-Q. Liang, J.-L. Liu, W.-D. Li, Z.-J. Li
Categories: cond-mat.other quant-ph
\\ ( http://arxiv.org/abs/0803.1889 , 260kb)
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Till next time,
Matt.

--
=========================================================================
Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email: mdavis_at_physics.uq.edu.au
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Australia.                    http://www.physics.uq.edu.au/people/mdavis/
=========================================================================
Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org
http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/
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Received on Fri Jul 04 2008 - 08:31:07 EST

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