# Matt's arXiv selection: week ending 20 March 2009

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Wed, 20 May 2009 16:57:48 +1000

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

Dear subscribers,

Geoff Lee deserves the credit for preparing this email. There are 28 new
preprints and 9 replacements:

------------------------------------------------------------------------------
\\
arXiv:0903.2261
Date: Thu, 12 Mar 2009 20:18:32 GMT (76kb)

Title: Modified Macroscopic Quantum Tunneling of a BEC close to a Feshbach
Resonance
Authors: N.T. Zinner and M. Th{\o}gersen
Categories: cond-mat.other
Comments: 4 pages, 3 figures, Revtex4
\\
We consider the stability and macroscopic decay of an ultracold trapped
Bose-Einstein condensate near a Feshbach resonance. Several types of atomic
species and resonances are investigated. Using a modified Gross-Pitaevskii
equation that includes higher-order terms and a multi-channel model of Feshbach
resonances, we find regions around experimentally measured Feshbach resonances
where macroscopic tunneling of the condensate is either suppressed or enhanced
by higher-order interactions. However, to see the effect in realistic
experiments requires very narrow resonances or very small condensates with
particle number of order $10^2$.
\\ ( http://arxiv.org/abs/0903.2261 , 76kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2263
Date: Thu, 12 Mar 2009 20:09:01 GMT (511kb)

Title: Shell-Model Monte Carlo Simulations of BCS-BEC Crossover in Few-Fermion
Systems
Authors: N.T. Zinner, K. M{\o}lmer, C. \"Ozen, D.J. Dean, K. Langanke
Categories: cond-mat.supr-con
Comments: 4 pages, 3 figures, Revtex4
\\
We study a trapped system of fermions with a zero-range two-body interaction
using the Shell-Model Monte Carlo method, providing {\em ab initio} results for
the low particle number limit where mean-field theory is not applicable. We
present results for the $N$-body energies as function of interaction strength,
particle number, and temperature. The subtle question of renormalization in a
finite model space is addressed and the convergence of our method and its
applicability across the BCS-BEC crossover is demonstrated. Comparison to N=2
analytics at zero and finite temperature, and to other calculations in the
literature for $N>2$ show very good agreement.
\\ ( http://arxiv.org/abs/0903.2263 , 511kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2346
Date: Fri, 13 Mar 2009 10:22:58 GMT (55kb)

Title: Phase diagram of imbalanced fermions in optical lattices
Authors: Xiaoling Cui and Yupeng Wang
Categories: cond-mat.supr-con
\\
The zero temperature phase diagrams of imbalanced two species fermions in 3D
optical lattices are investigated to evaluate the validity of the Fermi-Hubbard
model. It is found that depending on the filling factor, s-wave scattering
strength and lattice potential, the system may fall into the normal($N$) phase,
magnetized superfluid($SF_M$) or phase separation of $N$ and $BCS$ state. By
tuning these parameters, the superfluidity could be favorable by enhanced
effective couplings or suppressed by the increased band gap. The phase profiles
for imbalanced fermions in the presence of a harmonic trap are also
investigated under LDA, which show some novel structures to those without the
optical lattice.
\\ ( http://arxiv.org/abs/0903.2346 , 55kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2459
Date: Fri, 13 Mar 2009 19:11:12 GMT (91kb)

Title: Transport and Control in One-Dimensional Systems
Authors: L. F. Santos
Categories: cond-mat.stat-mech
Comments: 8 pages, 4 figures. Talk given at the workshop Integrable Quantum
Systems and Solvable Statistical Mechanics Models', Montreal, July 2008.
Submitted to J. Math. Phys
\\
We study transport of local magnetization in a Heisenberg spin-1/2 chain at
zero temperature. The system is initially prepared in a highly excited pure
state far from equilibrium and its evolution is analyzed via exact
diagonalization. Integrable and non-integrable regimes are obtained by
adjusting the parameters of the Hamiltonian, which allows for the comparison of
transport behaviors in both limits. In the presence of nearest neighbor
interactions only, the transport behavior in the integrable clean system
contrasts with the chaotic chain with on-site defects, oscillations in the
first suggesting ballistic transport and a fast decay in the latter indicating
diffusive transport. The results for a non-integrable system with frustration
are less conclusive, similarities with the integrable chain being verified. We
also show how methods of quantum control may be applied to chaotic systems to
induce a desired transport behavior, such as that of an integrable system.
\\ ( http://arxiv.org/abs/0903.2459 , 91kb)
-----------------------------------------------------------------------------
\\
arXiv:0903.2401
Date: Fri, 13 Mar 2009 13:05:54 GMT (3080kb)

Title: Unpublished opening lecture for the course on the theory of relativity
in Argentina, 1925
Authors: Albert Einstein, Alejandro Gangui and Eduardo L. Ortiz
Categories: physics.hist-ph physics.soc-ph
Comments: Companion paper to arXiv:0903.2064 . Published version available at
http://www.universoeinstein.com.ar/einsteinargentina.htm. Translated by
Alejandro Gangui and Eduardo L. Ortiz
Journal-ref: Science in Context, Vol. 21, issue 3, pp. 451-459 (2008)
\\
Honorable Rector, Honorable Professors, and Students of this University: In
these times of political and economic struggle and nationalistic fragmentation,
it is a particular joy for me to see people assembling here to give their
attention exclusively to the highest values that are common to us all. I am
glad to be in this blessed land before a small circle of people who are
interested in topics of science to speak on those issues that, in essence, are
the subject of my own meditations.. [abridged].
\\ ( http://arxiv.org/abs/0903.2401 , 3080kb)
-------------------------------------------------------------------------------
\\
arXiv:0903.2519
Date: Sat, 14 Mar 2009 01:02:26 GMT (146kb)

Title: High Precision Quantum Monte Carlo Study of the 2D Fermion Hubbard Model
Authors: C. N. Varney, C.-R. Lee, Z. J. Bai, S. Chiesa, M. Jarrell, and R. T.
Scalettar
Categories: cond-mat.str-el
Comments: 7 pages, 11 figures. Submitted to Phys. Rev. A
\\
We report large scale determinant Quantum Monte Carlo calculations of the
effective bandwidth, momentum-space Green's function, and magnetic correlations
of the square lattice fermion Hubbard Hamiltonian at half-filling. The sharp
Fermi surface of the non-interacting limit is significantly broadened by the
electronic correlations, but retains signatures of the approach to the edges of
the first Brillouin zone as the density increases. Finite size scaling of
simulations on large lattices allows us to extract the interaction dependence
of the antiferromagnetic order parameter, exhibiting its evolution from weak
coupling to the strong coupling Heisenberg limit. Our lattices provide improved
resolution of the Green's function in momentum space, allowing a more
quantitative comparison with time of flight optical lattice experiments.
\\ ( http://arxiv.org/abs/0903.2519 , 146kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2534
Date: Sat, 14 Mar 2009 08:47:16 GMT (555kb)

Title: Vortex-Induced Phase Slip Dissipation in a Toroidal Bose-Einstein
Condensate Flowing Trough a Barrier
Authors: F. Piazza, L. A. Collins, and A. Smerzi
Categories: cond-mat.other
\\
We study superfluid dissipation due to phase slips for a BEC flowing through
a repulsive barrier inside a torus. The barrier is adiabatically raised across
the annulus while the condensate flows with a finite quantized angular
momentum. We find that, at a critical height, a vortex moves radially from the
inner region and reaches the barrier to eventually circulate around the
annulus. At a slightly higher barrier, an anti-vortex also enters into the
torus from the outward region. The vortex and anti-vortex decrease the total
angular momentum by leaving behind their respective paths a $2 \pi$ phase slip.
When they collide or orbit along the same loop, the condensate suffers a global
$2\pi$ phase slip, and the total angular momentum decreases by one quantum. The
analysis is based on numerical simulations of the Gross-Pitaevskii equation
both in two- and three-dimensions.
\\ ( http://arxiv.org/abs/0903.2534 , 555kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2537
Date: Sat, 14 Mar 2009 09:48:14 GMT (79kb)

Title: Quantum Monte Carlo simulations for the Bose-Hubbard model with random
chemical potential; localized Bose-Einstein condensation without
superfluidity
Authors: Mitsuaki Tsukamoto, Makoto Tsubota
Categories: cond-mat.stat-mech
\\
The hardcore-Bose-Hubbard model with random chemical potential is
investigated using quantum Monte Carlo simulation. We consider two cases of
random distribution of the chemical potential: a uniformly random distribution
and a correlated distribution. The temperature dependences of the superfluid
density, the specific heat, and the correlation functions are calculated. If
the distribution of the randomness is correlated, there exists an intermediate
state, which can be thought of as a localized condensate state of bosons,
between the superfluid state and the normal state.
\\ ( http://arxiv.org/abs/0903.2537 , 79kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2552
Date: Sat, 14 Mar 2009 16:01:36 GMT (405kb)

Title: Quantum fluctuations of a Bose-Josephson junction in a
quasi-one-dimensional ring trap
Authors: N. Didier, A. Minguzzi, F.W.J. Hekking
Categories: cond-mat.mes-hall
\\
Using a Luttinger-liquid approach we study the quantum fluctuations of a
Bose-Josephson junction, consisting of a Bose gas confined to a quasi
one-dimensional ring trap which contains a localized repulsive potential
barrier. For an infinite barrier we study the one-particle and two-particle
static correlation functions. For the one-body density-matrix we obtain
different power-law decays depending on the location of the probe points with
respect to the position of the barrier. This quasi-long range order can be
experimentally probed in principle using an interference measurement. The
corresponding momentum distribution at small momenta is also shown to be
affected by the presence of the barrier and to display the universal power-law
behavior expected for an interacting 1D fluid. We also evaluate the particle
density profile, and by comparing with the exact results in the Tonks-Girardeau
limit we fix the nonuniversal parameters of the Luttinger-liquid theory. Once
the parameters are determined from one-body properties, we evaluate the
density-density correlation function, finding a remarkable agreement between
the Luttinger liquid predictions and the exact result in the Tonks-Girardeau
limit, even at the length scale of the Friedel-like oscillations which
characterize the behavior of the density-density correlation function at
intermediate distance. Finally, for a large but finite barrier we use the
one-body correlation function to estimate the effect of quantum fluctuations on
the renormalization of the barrier height, finding a reduction of the effective
Josephson coupling energy, which depends on the length of the ring and on the
interaction strength.
\\ ( http://arxiv.org/abs/0903.2552 , 405kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2568
Date: Sat, 14 Mar 2009 18:44:35 GMT (1756kb)

Title: Collisional cooling of ultra-cold atom ensembles using Feshbach
resonances
Authors: L. Mathey, Eite Tiesinga, Paul S. Julienne, Charles W. Clark
Categories: cond-mat.other
\\
We propose a new type of cooling mechanism for ultra-cold fermionic atom
ensembles, which capitalizes on the energy dependence of inelastic collisions
in the presence of a Feshbach resonance. We first discuss the case of a single
magnetic resonance, and find that the final temperature and the cooling rate is
limited by the width of the resonance. A concrete example, based on a p-wave
resonance of $^{40}$K, is given. We then improve upon this setup by using both
a very sharp optical or radio-frequency induced resonance and a very broad
magnetic resonance and show that one can improve upon temperatures reached with
current technologies.
\\ ( http://arxiv.org/abs/0903.2568 , 1756kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2707
Date: Mon, 16 Mar 2009 09:10:02 GMT (830kb)

Title: Non-Hermitian Generalization of the Bethe-Ansatz Excited States and
Dielectric Breakdown in the Hubbard Model out of Equilibrium
Authors: Takashi Oka and Hideo Aoki
Categories: cond-mat.stat-mech cond-mat.str-el
\\
Many-body models exactly solvable in nonequilibrium situations will serve to
deepen the understanding of nonequilibrium physics. Here we explore this by
applying the Dykhne-Davis-Pechukas approach to the dielectric breakdown of Mott
insulators in strong electric fields, which relates, via an analytic
continuation, the quantum tunneling rate with the Bethe-ansatz solution for
excited states in the Hubbard model extended to a non-Hermitian case. This has
enabled us to (i) reveal that two apparently unrelated theories, one with a
many-body Landau-Zener tunneling and the other a non-Hermitian approach, are in
fact intimately related, and (ii) give a picture for the breakdown in the
thermodynamic limit.
\\ ( http://arxiv.org/abs/0903.2707 , 830kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2723
Date: Mon, 16 Mar 2009 11:03:25 GMT (376kb)

Title: Exciton-polariton condensation in a natural two dimensional trap
Authors: D. Sanvitto, A. Amo, L. Vina, R. Andre, D. Solnyshkov and G. Malpuech
Categories: cond-mat.mes-hall cond-mat.other
\\
Bose Einstein condensation of exciton-polaritons has recently been reported
in homogeneous structures only affected by random in-plane fluctuations. We
have taken advantage of the ubiquitous defects in semiconductor microcavities
to reveal the spontaneous dynamical condensation of polaritons in the quantised
levels of a trap. We observe condensation in several quantized states, taking
their snapshots in real and reciprocal space. We show also the effect of
particle interactions for high occupations numbers, revealed by a change in the
confined wave function toward the Thomas Fermi profile.
\\ ( http://arxiv.org/abs/0903.2723 , 376kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2796
Date: Mon, 16 Mar 2009 16:29:02 GMT (63kb)

Title: Cooling atoms into entangled states
Authors: Giovanni Vacanti and Almut Beige
Categories: quant-ph
\\
We discuss the possibility to prepare highly entangled state by simply
cooling atoms into the ground state of an applied interaction Hamiltonian.
Different from previous proposals for state preparation via cooling [B. Kraus
et al., Phys. Rev. A 78, 042397 (2008) and F. Verstraete et al.,
arXiv:0804.1888], we do not require the existence of an exact dark state which
is the only stationary state of the system. Instead, our scheme is analog to
laser sideband cooling. Laser fields are applied such that the target state is
highly detuned, while all other qubit states are in resonance. After presenting
the general theory, we discuss concrete applications with one and two qubits.
\\ ( http://arxiv.org/abs/0903.2796 , 63kb)
--------------------------------------------------------------------------------
\\
arXiv:0903.2261 (*cross-listing*)
Date: Thu, 12 Mar 2009 20:18:32 GMT (76kb)

Title: Modified Macroscopic Quantum Tunneling of a BEC close to a Feshbach
Resonance
Authors: N.T. Zinner and M. Th{\o}gersen
Categories: cond-mat.other quant-ph
Comments: 4 pages, 3 figures, Revtex4
\\
We consider the stability and macroscopic decay of an ultracold trapped
Bose-Einstein condensate near a Feshbach resonance. Several types of atomic
species and resonances are investigated. Using a modified Gross-Pitaevskii
equation that includes higher-order terms and a multi-channel model of Feshbach
resonances, we find regions around experimentally measured Feshbach resonances
where macroscopic tunneling of the condensate is either suppressed or enhanced
by higher-order interactions. However, to see the effect in realistic
experiments requires very narrow resonances or very small condensates with
particle number of order $10^2$.
\\ ( http://arxiv.org/abs/0903.2261 , 76kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2745
Date: Mon, 16 Mar 2009 12:55:39 GMT (135kb)

Title: All-optical runaway evaporation to Bose-Einstein condensation
Authors: Jean-Francois Cl\'ement (LCFIO), Jean-Philippe Brantut (LCFIO), Martin
Robert De Saint Vincent (LCFIO), Robert A. Nyman (LCFIO), A. Aspect (LCFIO),
Thomas Bourdel (LCFIO), Philippe Bouyer (LCFIO)
Categories: physics.atom-ph
\\
We demonstrate runaway evaporative cooling directly with a tightly confining
optical dipole trap and achieve fast production of condensates of 1.5x10^5 87Rb
atoms. Our scheme is characterized by an independent control of the optical
trap confinement and depth, permitting forced evaporative cooling without
reducing the trap stiffness. Although our configuration is particularly well
suited to the case of 87Rb atoms in a 1565nm optical trap, where an efficient
initial loading is possible, our scheme is general and should allow all-optical
evaporative cooling at constant stiffness for most species.
\\ ( http://arxiv.org/abs/0903.2745 , 135kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2991
Date: Tue, 17 Mar 2009 15:54:18 GMT (3015kb)

Title: Density, phase and coherence properties of a low dimensional
Bose-Einstein systems moving in a disordered potential
Authors: Chaitanya Joshi, Sankalpa Ghosh (Physics Department, I. I. T. Delhi)
Categories: cond-mat.mes-hall cond-mat.dis-nn
Comments: 12 pages, 15 figures, EPJB style, accepted for publication in the
topical issue of EPJB on "Novel Quantum phases and Mesoscopic physics in
Quantum gases"
\\
We present a detailed numerical study of the dynamics of a disordered
one-dimensional Bose-Einstein condensates in position and momentum space. We
particularly focus on the region where non-linearity and disorder
simultaneously effect the time propagation of the condensate as well as the
possible interference between various parts of the matter wave. We report
oscillation between spatially extended and localized behavior for the
propagating condensate which dies down with increasing non-linearity. We also
report intriguing behavior of the phase fluctuation and the coherence
properties of the matter wave. We also briefly compare these behavior with that
of a two-dimensional condensate. We mention the relevance of our results to the
related experiments on Anderson localization and indicate the possibility of
future experiments
\\ ( http://arxiv.org/abs/0903.2991 , 3015kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3006
Date: Tue, 17 Mar 2009 17:07:01 GMT (22kb)

Title: Theory of Radio Frequency Spectroscopy of Polarized Fermi Gases
Authors: William Schneider, Vijay B. Shenoy, Mohit Randeria
Categories: cond-mat.other
\\
We present two exact results for singular features in the radio frequency
intensity $I(\omega)$ for ultracold Fermi gases. First, in the absence of final
state interactions, $I(\omega)$ has a universal high frequency tail $C\omega^{-3/2}$ for \emph{all} many-body states, where $C$ is Tan's contact.
Second, in a \emph{normal} Fermi liquid at T=0, $I(\omega)$ has a jump
discontinuity of $Z/(1 - m/m^{*})$, where $Z$ is the quasiparticle weight and
$m^*/m$ the mass renormalization. We then describe various approximations for
$I(\omega)$ in polarized normal gases. We show why an approximation that is
exact in the $n_\dn=0$ limit, fails qualitatively for $n_{\dn} > 0$: there is
no universal tail and sum rules are violated. The simple ladder approximation
is qualitatively correct for very small $n_{\dn}$, but not quantitatively.
\\ ( http://arxiv.org/abs/0903.3006 , 22kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3030
Date: Tue, 17 Mar 2009 19:35:34 GMT (19kb)

Title: Critical Behaviour in Trapped Strongly Interacting Fermi Gases
Authors: E. Taylor
Categories: cond-mat.stat-mech
\\
We investigate the width of the Ginzburg critical region and experimental
signatures of critical behaviour in strongly interacting trapped Fermi gases
close to unitarity, where the s-wave scattering length diverges. Despite the
fact that the width of the critical region is of the order unity, evidence of
critical behaviour in the thermodynamics of trapped gases is strongly
suppressed by their inhomogeneity. The specific heat of a harmonically confined
gas, for instance, is linear in the reduced temperature $\varepsilon = 1-T/T_c$
close to $T_c$. Using higher-order power-law potentials to confine the gas,
critical behaviour becomes more apparent and a lambda curve should be visible
in the specific heat.
\\ ( http://arxiv.org/abs/0903.3030 , 19kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2953
Date: Tue, 17 Mar 2009 12:14:21 GMT (946kb)

Title: Tapered optical fibers as tools for probing magneto-optical trap
characteristics
Authors: M.J. Morrissey, K. Deasy, Y. Wu, S. Chakrabarti and S. Nic Chormaic
Categories: quant-ph
\\
We present a novel technique for measuring the characteristics of a
magneto-optical trap for cold atoms by monitoring the spontaneous emission from
trapped atoms coupled into the guided mode of a tapered optical nanofiber. We
show that the nanofiber is highly sensitive to very small numbers of atoms
close to its surface. The size and shape of the MOT, determined by translating
the cold atom cloud across the tapered fiber, is in excellent agreement with
measurements obtained using the conventional method of fluorescence imaging
using a CCD camera. The coupling of atomic fluorescence into the tapered fiber
compared to those achieved by focusing the MOT fluorescence onto a photodiode
and it was seen that the tapered fiber gives slightly longer loading and
lifetime measurements due to the sensitivity of the fiber, even when very few
atoms are present.
\\ ( http://arxiv.org/abs/0903.2953 , 946kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2942
Date: Tue, 17 Mar 2009 11:07:21 GMT (850kb)

Title: Influence of a Feshbach resonance on the photoassociation of LiCs
Authors: J. Deiglmayr, P. Pellegrini, A. Grochola, M. Repp, R. C\^ot\'e, O.
Dulieu, R. Wester and M. Weidem\"uller
Categories: physics.atom-ph
Comments: Submitted to New Journal of Physics, Special Issue on Cold and
Ultracold molecules. 16 pages, 8 figures
\\
We analyse the formation of ultracold 7Li133Cs molecules in the rovibrational
ground state through photoassociation into the B1Pi state, which has recently
been reported [J. Deiglmayr et al., Phys. Rev. Lett. 101, 133004 (2008)].
Absolute rate constants for photoassociation at large detunings from the atomic
asymptote are determined and are found to be surprisingly large. The
photoassociation process is modeled using a full coupled-channel calculation
for the continuum state, taking all relevant hyperfine states into account. The
enhancement of the photoassociation rate is found to be caused by an echo' of
the triplet component in the singlet component of the scattering wave function
at the inner turning point of the lowest triplet a3Sigma+ potential. This
perturbation can be ascribed to the existence of a broad Feshbach resonance at
low scattering energies. Our results elucidate the important role of couplings
in the scattering wave function for the formation of deeply bound ground state
molecules via photoassociation.
\\ ( http://arxiv.org/abs/0903.2942 , 850kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3185
Date: Wed, 18 Mar 2009 15:32:34 GMT (1552kb)

Title: Ab-initio determination of Bose-Hubbard parameters for two ultracold
atoms in an optical lattice
Authors: Philipp Schneider, Sergey Grishkevich, and Alejandro Saenz
Categories: quant-ph
\\
We calculate numerically the exact energy spectrum of the six dimensional
problem of two interacting Bosons in a three-well optical lattice. The
particles interact via a full Born-Oppenheimer potential which can be adapted
to model the behavior of the s-wave scattering length at Feshbach resonances.
By adjusting the parameters of the corresponding Bose-Hubbard (BH) Hamiltonian
the deviation between the numerical energy spectrum and the BH spectrum is
minimized. This defines the optimal BH parameter set which we compare to the
standard parameters of the BH model. The range of validity of the BH model with
these parameter sets is examined, and an improved analytical prediction of the
interaction parameter is introduced. Furthermore, the extended BH model and
implications due to the energy dependence of the scattering length and
couplings to higher Bloch bands at a Feshbach resonance are discussed.
\\ ( http://arxiv.org/abs/0903.3185 , 1552kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3147
Date: Wed, 18 Mar 2009 12:12:25 GMT (100kb)

Title: Autoionization of an ultracold Rydberg gas through resonant dipole
coupling
Authors: T. Amthor, J. Denskat, C. Giese, N. N. Bezuglov, A. Ekers, L.
Cederbaum, M. Weidem\"uller
Categories: physics.atom-ph
\\
We investigate a possible mechanism for the autoionization of ultracold
Rydberg gases, based on the resonant coupling of Rydberg pair states to the
ionization continuum. Unlike an atomic collision where the wave functions begin
to overlap, the mechanism considered here involves only the long-range dipole
interaction and is in principle possible in a static system. It is related to
the process of intermolecular Coulombic decay (ICD). In addition, we include
the interaction-induced motion of the atoms and the effect of multi-particle
systems in this work. We find that the probability for this ionization
mechanism can be increased in many-particle systems featuring attractive or
repulsive van der Waals interactions. However, the rates for ionization through
resonant dipole coupling are very low. It is thus unlikely that this process
contributes to the autoionization of Rydberg gases in the form presented here,
but it may still act as a trigger for secondary ionization processes. As our
picture involves only binary interactions, it remains to be investigated if
collective effects of an ensemble of atoms can significantly influence the
ionization probability. Nevertheless our calculations may serve as a starting
point for the investigation of more complex systems, such as the coupling of
many pair states proposed in [Tanner et al., PRL 100, 043002 (2008)].
\\ ( http://arxiv.org/abs/0903.3147 , 100kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3202
Date: Wed, 18 Mar 2009 16:59:35 GMT (100kb)

Title: Collisions of bosonic ultracold polar molecules in microwave traps
Authors: Alexander V. Avdeenkov
Categories: physics.atom-ph
Comments: accepted for publication in New J. Phys. (special issue on ultracold
molecules)
\\
The collisions between linear polar molecules, trapped in a microwave field
with circular polarization, are theoretically analyzed. The microwave trap
suggested by DeMille \cite{DeMille} seems to be rather advantageous in
comparison with other traps. Here we have demonstrated that the microwave trap
can provide a successful evaporative cooling for polar molecules in a rather
broad range of frequencies of the AC-field. We suggested that not only ground
state polar molecules but also molecules in some other states can be safely
trapped.
But the state in which molecules can be safely loaded and trapped depends on
the frequency of the AC-field.
\\ ( http://arxiv.org/abs/0903.3202 , 100kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3194
Date: Wed, 18 Mar 2009 16:09:09 GMT (172kb)

Title: 60 years of Broken Symmetries in Quantum Physics (From the Bogoliubov
Theory of Superfluidity to the Standard Model)
Authors: D. V. Shirkov
Categories: physics.hist-ph cond-mat.supr-con hep-ph hep-th
Comments: 18 pages, 4 figures, to appear in Physics -- Uspekhi
\\
A retrospective historical overview of the phenomenon of spontaneous symmetry
breaking (SSB) in quantum theory, the issue that has been implemented in
particle physics in the form of the Higgs mechanism. The main items are:
-- The Bogoliubov's microscopical theory of superfluidity (1946);
-- The BCS-Bogoliubov theory of superconductivity (1957);
-- Superconductivity as a superfluidity of Cooper pairs (Bogoliubov - 1958);
-- Transfer of the SSB into the QFT models (early 60s);
-- The Higgs model triumph in the electro-weak theory (early 80s).
The role of the Higgs mechanism and its status in the current Standard Model
is also touched upon.
\\ ( http://arxiv.org/abs/0903.3194 , 172kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3282
Date: Thu, 19 Mar 2009 08:39:09 GMT (374kb)

Title: Direct observation of number squeezing in an optical lattice
Authors: A. Itah, H. Veksler, O. Lahav, A. Blumkin, C. Moreno, C. Gordon and J.
Steinhauer
Categories: cond-mat.other
\\
We present an in-situ study of an optical lattice with tunneling and single
lattice site resolution. This system provides an important step for realizing a
quantum computer. The real-space images show the fluctuations of the atom
number in each site. The sub-Poissonian distribution results from the approach
to the Mott insulator state, combined with the dynamics of density-dependent
losses, which result from the high densities of optical lattice experiments.
These losses are clear from the shape of the lattice profile. Furthermore, we
find that the lattice is not in the ground state despite the momentum
distribution which shows the reciprocal lattice. These effects may well be
relevant for other optical lattice experiments, past and future. The lattice
beams are derived from a microlens array, resulting in lattice beams which are
perfectly stable relative to one another.
\\ ( http://arxiv.org/abs/0903.3282 , 374kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3284
Date: Thu, 19 Mar 2009 08:23:33 GMT (1232kb)

Title: Light-pulse atom interferometry in microgravity
Authors: Guillaume Stern (LCFIO, SYRTE), Baptiste Battelier (LCFIO), R\'emi
Geiger (LCFIO), Gael Varoquaux (LCFIO), Andr\'e Villing (LCFIO), Fr\'ed\'eric
Moron (LCFIO), Olivier Carra (ONERA), Nassim Zahzam (ONERA), Yannick Bidel
(ONERA), Oualid Chaibi (SYRTE), Frank Pereira Dos Santos (SYRTE), Alexandre
Bresson (ONERA), Arnaud Landragin (SYRTE), Philippe Bouyer (LCFIO)
Categories: cond-mat.other
\\
We describe the operation of a light pulse interferometer using cold 87Rb
atoms in reduced gravity. Using a series of two Raman transitions induced by
light pulses, we have obtained Ramsey fringes in the low gravity environment
achieved during parabolic flights. With our compact apparatus, we have operated
in a regime which is not accessible on ground. In the much lower gravity
environment and lower vibration level of a satellite, our cold atom
interferometer could measure accelerations with a sensitivity orders of
magnitude better than the best ground based accelerometers and close to proven
spaced-based ones.
\\ ( http://arxiv.org/abs/0903.3284 , 1232kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3345
Date: Thu, 19 Mar 2009 15:11:13 GMT (45kb)

Title: Time-resolved measurement of Landau-Zener tunneling in periodic
potentials
Authors: A. Zenesini and H. Lignier and G. Tayebirad and J. Radogostowicz and
D. Ciampini and R. Mannella and S. Wimberger and O. Morsch and E. Arimondo
Categories: cond-mat.other
\\
We report time-resolved measurements of Landau-Zener tunneling of
Bose-Einstein condensates in accelerated optical lattices, clearly resolving
the step-like time dependence of the band populations. Using different
experimental protocols we were able to measure the tunneling probability both
in the adiabatic and in the diabatic bases of the system. We also
experimentally determine the contribution of the momentum width of the Bose
condensates to the width of the tunneling steps and discuss the implications
for measuring the jump time in the Landau-Zener problem.
\\ ( http://arxiv.org/abs/0903.3345 , 45kb)
------------------------------------------------------------------------------
\\
arXiv:0903.3348
Date: Thu, 19 Mar 2009 15:24:04 GMT (1633kb)

Title: Universal Four-Boson States in Ultracold Molecular Gases: Resonant
Effects in Dimer-Dimer Collisions
Authors: J. P. D'Incao, J. von Stecher, and Chris H. Greene
Categories: physics.atom-ph
\\
We study the manifestations of universal four-body physics in ultracold
dimer-dimer collisions.
We show that resonant features associated with three-body Efimov physics and
dimer-dimer scattering lengths are universally related. The emergence of
universal four-boson states allows for the tunability of the dimer-dimer
interaction, thus enabling the future study of ultracold molecular gases with
both attractive and repulsive interactions. Moreover, our study of the
interconversion between dimers and Efimov trimers shows that $B_{2}+B_{2}\to B_{3}+B$ rearrangement reactions can provide an efficient trimer formation
mechanism. Our analysis of the temperature dependence of this reaction provides
an interpretation of the available experimental data and sheds light on the
possible experimental realization of rearrangement processes in ultracold
gases.
\\ ( http://arxiv.org/abs/0903.3348 , 1633kb)
------------------------------------------------------------------------------

The replacements:

------------------------------------------------------------------------------
\\
arXiv:cond-mat/0610116
replaced with revised version Fri, 13 Mar 2009 14:43:48 GMT (18kb)

Title: Resonant Dimer Relaxation in Cold Atoms with a Large Scattering Length
Authors: Eric Braaten (Ohio State U.), H.-W. Hammer (Bonn U.)
Categories: cond-mat.other nucl-th
Comments: 4 pages, 2 eps figures, normalization error in figures corrected,
equations unchanged
Report-no: HISKP-TH-06-26
Journal-ref: Phys.Rev.A75:052710,2007
DOI: 10.1103/PhysRevA.75.052710
\\ ( http://arxiv.org/abs/cond-mat/0610116 , 18kb)
------------------------------------------------------------------------------
\\
arXiv:0903.2242
replaced with revised version Fri, 13 Mar 2009 11:41:19 GMT (552kb,D)

Title: Quantum Noise Interference and Back-action Cooling in Cavity
Nanomechanics
Authors: Florian Elste, S. M. Girvin, A. A. Clerk
Categories: cond-mat.mes-hall
Comments: 4+ pages, 2 figures. Error in second last paragraph corrected
\\ ( http://arxiv.org/abs/0903.2242 , 552kb)
------------------------------------------------------------------------------
\\
arXiv:0711.1772
replaced with revised version Mon, 16 Mar 2009 10:49:40 GMT (337kb)

Title: Bloch oscillations of atoms in an optical multiphoton potential
Authors: Tobias Salger, Gunnar Ritt, Carsten Geckeler, Sebastian Kling, Martin
Weitz
Categories: cond-mat.other
Journal-ref: Phys. Rev. A 79, 011605(R) (2009)
DOI: 10.1103/PhysRevA.79.011605
\\ ( http://arxiv.org/abs/0711.1772 , 337kb)
------------------------------------------------------------------------------
\\
arXiv:0811.3623
replaced with revised version Mon, 16 Mar 2009 15:04:08 GMT (201kb)

Title: Superfluid-density of the ultra-cold Fermi gas in optical lattices
Authors: T. Paananen
Categories: cond-mat.other
\\ ( http://arxiv.org/abs/0811.3623 , 201kb)
------------------------------------------------------------------------------
\\
arXiv:0806.1211
replaced with revised version Tue, 17 Mar 2009 11:20:36 GMT (508kb)

Title: Universal dephasing in a chiral 1D interacting fermion system
Authors: Clemens Neuenhahn, Florian Marquardt
Categories: cond-mat.mes-hall
Comments: 5 pages, 3 figures; minor changes, version as published;
Journal-ref: Physical Review Letters 102, 046806 (2009)
DOI: 10.1103/PhysRevLett.102.046806
\\ ( http://arxiv.org/abs/0806.1211 , 508kb)
------------------------------------------------------------------------------
\\
arXiv:0903.1647
replaced with revised version Mon, 16 Mar 2009 22:19:03 GMT (21kb)

Title: Stability of low-dimensional multicomponent Bose gases
Authors: Alexei Kolezhuk
Categories: cond-mat.other cond-mat.str-el
Comments: 4 pages, 2 figures; (v2) shortened, references corrected
\\ ( http://arxiv.org/abs/0903.1647 , 21kb)
------------------------------------------------------------------------------
\\
arXiv:0712.0880
replaced with revised version Wed, 18 Mar 2009 06:59:58 GMT (100kb)

Title: Loss of Superfluidity in Bose-Einstein Condensate in an Optical lattice
with Two- and Three-Body Interactions
Authors: Priyam Das, Manan Vyas and Prasanta K. Panigrahi
Categories: cond-mat.other
\\ ( http://arxiv.org/abs/0712.0880 , 100kb)
------------------------------------------------------------------------------
\\
arXiv:0810.3088
replaced with revised version Wed, 18 Mar 2009 11:45:40 GMT (150kb)

Title: Spacetime analogue of Bose-Einstein condensates: Bogoliubov-de Gennes
formulation
Authors: Yasunari Kurita, Michikazu Kobayashi, Takao Morinari, Makoto Tsubota,
Hideki Ishihara
Categories: cond-mat.other gr-qc
Report-no: OCU-PHYS-305, AP-GR-62, YITP-08-77
\\ ( http://arxiv.org/abs/0810.3088 , 150kb)
------------------------------------------------------------------------------
\\
arXiv:0811.2436
replaced with revised version Thu, 19 Mar 2009 11:16:03 GMT (249kb)

Title: Stationary waves in a supersonic flow of a two-component Bose gas
Authors: L.Yu. Kravchenko, D.V. Fil
Categories: cond-mat.other
\\ ( http://arxiv.org/abs/0811.2436 , 249kb)
------------------------------------------------------------------------------

Till next time,
Matt.

--
=========================================================================
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
http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/
=========================================================================
Legal stuff: Unless stated otherwise, this e-mail represents only the
views of the sender and not the views of the University of Queensland
=========================================================================

Received on Thu May 21 2009 - 15:50:53 EST

This archive was generated by hypermail 2.2.0 : Fri May 29 2009 - 09:16:40 EST