Matt's arXiv selection: week ending 26 December 2008

From: Matthew Davis <>
Date: Tue, 24 Feb 2009 20:29:00 +1000

The following message was sent to the matts_arxiv list by Matthew Davis <>

It almost seems like ancient history... there were 36 new preprints and 9

Date: Fri, 19 Dec 2008 07:54:47 GMT (208kb)

Title: Universal three-body bound states in planar atomic wave guides
Authors: Ludovic Pricoupenko (LPTMC), Paolo Pedri (LPTMC, LPL)
Categories: cond-mat.other
   Shallow trimers are found for mixtures of two atomic species strongly trapped
in a quasi two-dimensional atomic wave guide. The binding energies are
functions of the 2D-scattering length and of the mass ratio and can be thus
tuned by various ways. These universal trimers are composed of two identical
non interacting particles and of a third particle of the other species.
Depending on the statistics of the two identical particles, the trimers have an
odd (fermions) or even (bosons) internal angular momentum. These results permit
to draw conclusions on the stability issue for the quasi-2D gaseous phase of
heteronuclear dimers.
\\ ( , 208kb)
Date: Fri, 19 Dec 2008 12:01:32 GMT (107kb)

Title: Cold atoms in double-well optical lattices
Authors: V.I. Yukalov and E.P. Yukalova
Categories: cond-mat.mes-hall cond-mat.stat-mech
Comments: Latex file, 24 pages, 3 figures
Journal-ref: Phys. Rev. A 78 (2008) 063610-10
   Cold atoms, loaded into an optical lattice with double-well sites, are
considered. Pseudospin representation for an effective Hamiltonian is derived.
The system in equilibrium displays two phases, ordered and disordered. The
second-order phase transition between the phases can be driven either by
temperature or by changing the system parameters. Collective pseudospin
excitations have a gap disappearing at the phase-transition point. Dynamics of
atoms is studied, when they are loaded into the lattice in an initially
nonequilibrium state. It is shown that the temporal evolution of atoms,
contrary to their equilibrium thermodynamics, cannot be described in the
mean-field approximation, since it results in a structurally unstable dynamical
system, but a more accurate description is necessary taking account of
attenuation effects.
\\ ( , 107kb)
Date: Fri, 19 Dec 2008 19:11:02 GMT (149kb)

Title: Alkaline-Earth Atoms as Few-Qubit Quantum Registers
Authors: Alexey V. Gorshkov, Ana Maria Rey, Andrew J. Daley, Martin M. Boyd,
   Jun Ye, Peter Zoller, Mikhail D. Lukin
Categories: quant-ph
Comments: 4 pages, 2 figures
   We propose and analyze a novel approach to quantum information processing, in
which multiple qubits can be encoded and manipulated using electronic and
nuclear degrees of freedom associated with individual alkaline-earth atoms
trapped in an optical lattice. Specifically, we describe how the qubits within
each register can be individually manipulated and measured with sub-wavelength
optical resolution. We also show how such few-qubit registers can be coupled to
each other in optical superlattices via conditional tunneling to form a
scalable quantum network. Finally, potential applications to quantum
computation and precision measurements are discussed.
\\ ( , 149kb)
Date: Fri, 19 Dec 2008 03:40:56 GMT (102kb)

Title: Is a rubidium cell with long decay time always useful for generating a
   non-classical photon pair?
Authors: Qun-Feng Chen, Xiao-Song Lu, Bao-Sen Shi, and Guang-Can Guo
Categories: quant-ph
Comments: 3 pages, 5 figures
   We experimentally find an interesting and unexpected thing: a rubidium cell
with long decay time can not be used to generate a non-classical correlated
photon pair via the D2 transition of $^{87}$Rb using four-wave mixing
configuration [Opt. Express {\bf 16}, 21708 (2008)]. In this work, we give a
detail theoretical analysis on the EIT of hot $^{87}$Rb with different ground
decay time, which shows a probable reason why a rubidium cell with long decay
time is not a useful candidate for preparation of a non-classical photon pair
via the D2 transition. The simulations agree well with the experimental
results. We believe our find is very instructive to such kind of research.
\\ ( , 102kb)
Date: Fri, 19 Dec 2008 16:41:29 GMT (68kb)

Title: Two-dimensional weakly interacting Bose gas: equation of state
Authors: G.E. Astrakharchik, J. Boronat, J. Casulleras, I.L. Kurbakov, and
   Yu.E. Lozovik
Categories: quant-ph cond-mat.other
Comments: 2 figures, 2 tables
   The equation of state of a weakly interacting two-dimensional Bose gas is
studied at zero temperature by means of quantum Monte Carlo methods. Going down
to as low densities as na^2 ~ 10^{-67} permits us for the first time to obtain
agreement on beyond mean-field level between predictions of perturbative
methods and direct many-body numerical simulation, thus providing an answer to
the fundamental question of the equation of state of a two-dimensional dilute
Bose gas. We also show that the measure of the frequency of a breathing
collective oscillation in a trap at very low densities can be used to test the
universal equation of state of a two-dimensional Bose gas.
\\ ( , 68kb)
arXiv:0812.3052 (*cross-listing*)
Date: Tue, 16 Dec 2008 13:33:51 GMT (21kb)
Date (revised v2): Wed, 17 Dec 2008 10:29:59 GMT (21kb)

Title: Dephasing of entangled atoms as an improved test of quantum gravity
Authors: Mark S. Everitt, Martin L. Jones, Benjamin T. H. Varcoe
Categories: gr-qc quant-ph
Comments: 4 pages, 2 figures
   In a recent article Wang et al. (Class. Quantum Grav. 23 (2006) L59),
demonstrated that phase of a particle fluctuated due to interactions with
random deviations of a conformal gravitational field. Furthermore they
demonstrated that atom interferometers were sensitive to these fluctuations and
that sensitivity to Planck scale effects could be achieved with a sufficiently
sensitive interferometer. In this paper we demonstrate that a class of
entangled states, the N-atom Greenberger-Horne-Zeilinger (GHZ) states, provide
a better scaling than atom interferometry and that current experiments are
capable of making a significant impact in this field. We outline an experiment
which uses atomic beams of rubidium atoms excited to Rydberg states that
undergo controlled collisions in high-Q microwave resonators in a sequence that
makes the resulting state highly sensitive to conformal field fluctuations. We
show that a significant advance in sensitivity is possible.
\\ ( , 21kb)
Date: Mon, 22 Dec 2008 12:35:05 GMT (1028kb)

Title: Trapping cold atoms using surface-grown carbon nanotubes
Authors: P. G. Petrov, S. Machluf, S. Younis, R. Macaluso, T. David, B. Hadad,
   Y. Japha, M. Keil, E. Joselevich, R. Folman
Categories: cond-mat.other
   We present a feasibility study for loading cold atomic clouds into magnetic
traps created by single-wall carbon nanotubes grown directly onto dielectric
surfaces. We show that atoms may be captured for experimentally sustainable
nanotube currents, generating trapped clouds whose densities and lifetimes are
sufficient to enable detection by simple imaging methods. This opens the way
for a novel type of conductor to be used in atomchips, enabling atom trapping
at sub-micron distances, with implications for both fundamental studies and for
technological applications.
\\ ( , 1028kb)
Date: Sat, 20 Dec 2008 07:51:43 GMT (58kb)

Title: Quantum liquid crystals in imbalanced Fermi gas: fluctuations and
   fractional vortices in Larkin-Ovchinnikov states
Authors: Leo Radzihovsky, Ashvin Vishwanath
Categories: cond-mat.supr-con
Comments: 4 pages, 1 figure
   We develop a low-energy model of a unidirectional Larkin-Ovchinnikov (LO)
state. Because the underlying rotational and translational symmetries are
broken spontaneously, this gapless superfluid is a smectic liquid crystal, that
exhibits fluctuations that are qualitatively stronger than in a conventional
superfluid, thus requiring a fully nonlinear description of its Goldstone
modes. Consequently, at nonzero temperature the LO superfluid is an algebraic
phase even in 3d. It exhibits half-integer vortex-dislocation defects, whose
unbinding leads to transitions to a superfluid nematic and other phases. In 2d
at nonzero temperature, the LO state is always unstable to a charge-4 nematic
superfluid. We expect this superfluid liquid-crystal phenomenology to be
realizable in imbalanced resonant Fermi gases trapped isotropically.
\\ ( , 58kb)
Date: Sat, 20 Dec 2008 14:39:32 GMT (62kb)

Title: Quantized vortices and superflow in arbitrary dimensions: Structure,
   energetics and dynamics
Authors: Paul M. Goldbart and Florin Bora (University of Illinois at
Categories: cond-mat.stat-mech
Comments: 35 pages, 7 figures
   The structure and energetics of superflow around quantized vortices, and the
motion inherited by these vortices from this superflow, are explored in the
general setting of the superfluidity of helium-four in arbitrary dimensions.
The vortices may be idealized as objects of co-dimension two, such as
one-dimensional loops and two-dimensional closed surfaces, respectively, in the
cases of three- and four-dimensional superfluidity. By using the analogy
between vorticial superflow and Ampere-Maxwell magnetostatics, the equilibrium
superflow containing any specified collection of vortices is constructed. The
energy of the superflow is found to take on a simple form for vortices that are
smooth and asymptotically large, compared with the vortex core size. The motion
of vortices is analyzed in general, as well as for the special cases of
hyper-spherical and weakly distorted hyper-planar vortices. In all dimensions,
vortex motion reflects vortex geometry. In dimension four and higher, this
includes not only extrinsic but also intrinsic aspects of the vortex shape,
which enter via the first and second fundamental forms of classical geometry.
For hyper-spherical vortices, which generalize the vortex rings of three
dimensional superfluidity, the energy-momentum relation is determined. Simple
scaling arguments recover the essential features of these results, up to
numerical and logarithmic factors.
\\ ( , 62kb)
Date: Sat, 20 Dec 2008 20:51:02 GMT (266kb)

Title: Phase transition to a Bose-Einstein condensate with atomic polaritons
Authors: A. P. Alodjants, A. Yu. Leksin, S. M. Arakelian, J. Nipper, U. Vogl,
   M. Weitz
Categories: cond-mat.mes-hall
Comments: 12 pages, 10 postscript figures, REVTeX 4, presented to Phys. Rev. A
   We study a critical phenomenon for atomic polaritons in a cavity for the
interaction of two-level atoms with quantized optical radiation in the strong
coupling regime. We derive an expression for the critical temperature when a
Bardeen-Cooper-Schrieffer (BCS)-type phase transition between the normal and a
superfluid state occurs. Such a transition results in the appearance of a
macroscopic polarization of atomic medium at non-zero frequency. Important is
that the critical temperature of the phase transition is essentially dependent
on photon numbers in the cavity. We predict the densities at which the
crossover from BCS state to Bose-Einstein condensate (BEC) state takes place
for a two dimensional gas of polaritons in the cavity. A prerequisite for such
a phase transition is a fully thermalised system. We also describe the
experiment on atom-light interaction with rubidium atoms in an ultrahigh buffer
gas chamber. The lifetime of excited state rubidium atoms in the buffer gas
chamber is studied. Further, an observed detuning dependence of the saturated
lineshape is interpreted as evidence for thermal equilibrium of coupled
atom-light states.
\\ ( , 266kb)
Date: Sun, 21 Dec 2008 18:17:48 GMT (2835kb,D)

Title: The dynamics of quantum vortices in a toroidal trap
Authors: Peter Mason, Natalia G. Berloff
Categories: cond-mat.other
Comments: Submitted to Phys. Rev. A. 18 pages, 22 figures
   The dynamics of quantum vortices in a two-dimensional annular condensate are
considered by numerically simulating the Gross-Pitaevskii equation. Families of
solitary wave sequences are reported, both without and with a persistent flow,
for various values of interaction strength. It is shown that in the toroidal
geometry the dispersion curve of solutions is much richer than in the cases of
a semi-infinite channel or uniform condensate studied previously. In
particular, the toroidal condensate is found to have states of single vortices
at the same position and circulation that move with different velocities. The
stability of the solitary wave sequences for the annular condensate without a
persistent flow are also investigated by numerically evolving the solutions in
time. In addition, the interaction of vortex-vortex pairs and vortex-antivortex
pairs is considered and it is demonstrated that the collisions are either
elastic or inelastic depending on the magnitude of the angular velocity. The
similarities and differences between numerically simulating the
Gross-Pitaevskii equation and using a point vortex model for these collisions
are elucidated.
\\ ( , 2835kb)
Date: Mon, 22 Dec 2008 01:17:28 GMT (462kb)

Title: Vortex sheet in rotating two-component Bose-Einstein condensates
Authors: Kenichi Kasamatsu and Makoto Tsubota
Categories: cond-mat.other cond-mat.mes-hall
Comments: 8 pages, 7 figures
   We investigate vortex states of immiscible two-component Bose-Einstein
condensates under rotation. When the imbalance of the intracomponent parameter
is small, each component makes up of winding chains of singly quantized
vortices, vortex sheet, instead of periodic vortex lattices. We discuss the
details of this structure through numerical simulations of the Gross-Pitaevskii
equations and the analytical estimate of the sheet distance, determined by the
competition between the surface tension of the domain wall and the kinetic
energy of the superflow via quantized vortices. By comparing the several length
scales in this system, the phase diagram of the vortex state is obtained.
\\ ( , 462kb)
Date: Mon, 22 Dec 2008 11:29:55 GMT (88kb,D)

Title: Self-organization in dissipative optical lattices
Authors: G. Baris Bagci and Ugur Tirnakli
Categories: cond-mat.stat-mech
Comments: 9 pages, 1 fig
   We show that the transition from Gaussian to the q-Gaussian distributions
occurring in atomic transport in dissipative optical lattices can be
interpreted as self-organization by recourse to a modified version of
Klimontovich's S-theorem. As a result, we find that self-organization is
possible in the transition regime, only where the second moment <p^{2}> is
finite. Therefore, the nonadditivity parameter q is confined within the range
1<q<5/3, although whole spectrum of q values i.e., 1<q<3, is considered
theoretically possible. The range of q values obtained from the modified
S-theorem is also confirmed by the experiments carried out by Douglas et al.
[Phys. Rev. Lett. 96, 110601 (2006)].
\\ ( , 88kb)
Date: Mon, 22 Dec 2008 20:49:36 GMT (320kb)

Title: Fragmented many-body ground states in a single trap for bosons with
   long-range interactions
Authors: Philipp Bader and Uwe R. Fischer
Categories: cond-mat.other
Comments: 4 pages of RevTex3, 3 figures
   We investigate whether the many-body states of bosons in a generalized
two-mode model with arbitrary long-range interactions and single-particle
orbitals are coherent (condensed) or fragmented. It is demonstrated that
fragmentation can take place in a single trap for positive values of the
interaction couplings, implying that the system is potentially stable.
Furthermore, the degree of fragmentation is shown to be insensitive to small
perturbations on the single-particle level.
\\ ( , 320kb)
Date: Mon, 22 Dec 2008 14:21:06 GMT (1229kb)

Title: Fermionized photons in an array of driven dissipative nonlinear cavities
Authors: Iacopo Carusotto, Dario Gerace, Hakan Tureci, Simone De Liberato,
   Cristiano Ciuti, Atac Imamoglu
Categories: cond-mat.other cond-mat.mes-hall
   We theoretically investigate the optical response of a one-dimensional array
of strongly nonlinear optical microcavities. When the optical nonlinearity is
much larger than both losses and inter-cavity tunnel coupling, the
non-equilibrium steady state of the system is reminiscent of a strongly
correlated Tonks-Girardeau gas of impenetrable bosons. Signatures of strong
correlations are identified in the absorption spectrum of the system, as well
as in the intensity correlations of the emitted light. Possible experimental
implementations in state-of-the-art solid-state devices are discussed.
\\ ( , 1229kb)
arXiv:0812.2701 (*cross-listing*)
Date: Mon, 15 Dec 2008 01:52:38 GMT (1221kb,D)

Title: Electro-Optical Nano-Traps for Neutral Atoms
Authors: Brian Murphy and Lene Vestergaard Hau
Categories: physics.atom-ph cond-mat.mes-hall hep-ph physics.optics quant-ph
Comments: 11 pages, 3 figures
   We propose a new class of nanoscale electro-optical traps for neutral atoms.
A prototype is the toroidal trap created by a suspended, charged carbon
nanotube decorated with a silver nanosphere dimer. An illuminating laser field,
blue detuned from an atomic resonance frequency, is strongly focused by
plasmons induced in the dimer and generates both a repulsive potential barrier
near the nanostructure surface and a large viscous damping force that
facilitates trap loading. Atoms with velocities of several meters per second
may be loaded directly into the trap via spontaneous emission of just two
\\ ( , 1221kb)
Date: Fri, 19 Dec 2008 22:11:34 GMT (1487kb,D)

Title: Microfabricated Chip Traps for Ions
Authors: J. M. Amini, J. Britton, D. Leibfried, D. J. Wineland
Categories: quant-ph
Comments: To be included as a chapter in the forthcoming book "Atom Chips"
   edited by J. Reichel and V. Vuletic (to be published by WILEY-VCH)
   This submission is an introduction to microfabricated ion traps. We cover the
basics of Paul traps, various geometries for realizing the traps, a number of
design considerations, and, finally, a review of existing microfabricated
\\ ( , 1487kb)
Date: Sun, 21 Dec 2008 18:14:26 GMT (875kb)

Title: Atomic quantum superposition state generation via optical probing
Authors: Anne E. B. Nielsen, Uffe V. Poulsen, Antonio Negretti, and Klaus
Categories: quant-ph
Comments: 10 pages, 9 figures
   We analyze the performance of a protocol to prepare an atomic ensemble in a
superposition of two macroscopically distinguishable states. The protocol
relies on conditional measurements performed on a light field, which interacts
with the atoms inside an optical cavity prior to detection, and we investigate
cavity enhanced probing with continuous beams of both coherent and squeezed
light. The stochastic master equations used in the analysis are expressed in
terms of the Hamiltonian of the probed system and the interaction between the
probed system and the probe field and are thus quite generally applicable.
\\ ( , 875kb)
Date: Mon, 22 Dec 2008 00:29:59 GMT (83kb)

Title: Qubit residence time measurements with a Bose-Einstein condensate
Authors: D.Sokolovski
Categories: quant-ph
   We show that an electrostatic qubit located near a Bose-Einstein condensate
trapped in a symmetric double-well potential can be used to measure the
duration the qubit has spent in one of its quantum states. The stronq, medium
and weak measurement regimes are analysed and a new type of Zeno effect is
discussed. The analogy between the residence and the traversal (tunnelling)
times is highlighted.
\\ ( , 83kb)
Date: Mon, 22 Dec 2008 05:00:27 GMT (125kb)

Title: The Bounded Anharmonic Oscillators: a simple approach
Authors: F. Maiz and M. Nasr
Categories: quant-ph
Comments: 14 pages
   We have developed a simple method to solve anharmonic oscillators equations.
The idea of our method is mainly based on the partitioning of the potential
curve into (n+1) small intervals, solving the Schr\"odinger equation in each
subintervals, and writing the continuity conditions of each solutions at each
subintervals boundary, which leads to the energy quantification condition, so
to the energy levels, and finally, one can calculate the exact wave function
associated to each energy level. Our method has been applied to three examples:
the well-known square well, the bounded and unbounded harmonic oscillators, the
Morse potential, and some anharmonic oscillators bounded by two infinite walls.
Our method is more realistic, simpler, with high degree of accuracy, both
satisfactory and not computationally complicated, and applicable for any forms
of potential. Our results agree very well with the preceding ones.
\\ ( , 125kb)
Date: Mon, 22 Dec 2008 01:27:39 GMT (35kb)

Title: Detection of quantum orders of ultracold atoms in optical lattices by
   off-resonant scattering of cavity photons
Authors: Jinwu Ye, Jiangming Zhang, Wuming Liu, Keye Zhang, Yan Li, Zhe-Yu Ou
   and Weiping Zhang
Categories: physics.atom-ph physics.optics
   We show that cavity enhanced off-resonant light scattering from ultra-cold
atoms loaded on optical lattices can detect the nature of quantum phases such
as the ground state, the excitation spectrum of these quantum phases and also
the universality class of any possible second order quantum phase transitions
between these phases. These quantum phases include not only the well known
superfluid and Mott insulating phases and the superfluid to Mott transition,
but also exotic phases such as charge density wave, valence bond solid and
several kinds of supersolids in one, two and three dimensional optical lattices
and quantum phases transitions between these phases. We also address how the
quantum information encoded in these quantum phases of matter can be
transferred to the light.
\\ ( , 35kb)
Date: Mon, 22 Dec 2008 13:54:46 GMT (499kb,D)

Title: Stark deceleration of lithium hydride molecules
Authors: S. K. Tokunaga, J. M. Dyne, E. A. Hinds and M. R. Tarbutt
Categories: physics.atom-ph
Comments: 14 pages, 6 figures
   We describe the production of cold, slow-moving LiH molecules. The molecules
are produced in the ground state using laser ablation and supersonic expansion,
and population is transferred efficiently to the rotationally excited state
using narrowband radiation at the rotational frequency of 444 GHz. The
molecules are then decelerated to low speed using a 100 stage Stark
decelerator. Two different modes of deceleration are demonstrated and compared.
We compare our experimental data to the results of simulations and find good
agreement. These simulations include the velocity dependence of the detection
efficiency and the probability of transitions between the weak-field seeking
and strong-field seeking quantum states. Together, the experimental and
simulated data provide information about the spatial extent of the source of
molecules. We consider the prospects for future trapping and sympathetic
cooling experiments.
\\ ( , 499kb)
Date: Mon, 22 Dec 2008 18:04:04 GMT (173kb)

Title: A simplified optical lattice clock
Authors: N. Poli, M. G. Tarallo, M. Schioppo, C. W. Oates and G. M. Tino
Categories: physics.atom-ph
Comments: 6 pages, 5 figures, submitted to Appl. Phys. B
   Existing optical lattice clocks demonstrate a high level of performance, but
they remain complex experimental devices. In order to address a wider range of
applications including those requiring transportable devices, it will be
necessary to simplify the laser systems and reduce the amount of support
hardware. Here we demonstrate two significant steps towards this goal:
demonstration of clock signals from a Sr lattice clock based solely on
semiconductor laser technology, and a method for finding the clock transition
(based on a coincidence in atomic wavelengths) that removes the need for
extensive frequency metrology hardware. Moreover, the unexpected high contrast
in the signal revealed evidence of density dependent collisions in Sr-88 atoms.
\\ ( , 173kb)
Date: Tue, 23 Dec 2008 12:47:11 GMT (41kb)

Title: Universal behavior of a trapped Fermi superfluid in the BCS-unitarity
Authors: S. K. Adhikari
Categories: cond-mat.other
Comments: 6 pages
   From an extensive calculation of static properties of a trapped Fermi
superfluid at zero temperature using a density-functional formulation, we
demonstrate a universal behavior of its observables, such as energy, chemical
potential, radius etc., over the crossover from the BCS limit to unitarity
leading to scaling over many orders of magnitude in fermion number. This
scaling allows to predict the static properties of the system, with a large
number ($\sim 10^5$) of fermions, over the crossover with an error of 1-2%,
from the knowledge of those for a small number ($\sim 10$) of fermions.
\\ ( , 41kb)
Date: Tue, 23 Dec 2008 16:27:37 GMT (196kb,D)

Title: Quantum Simulation of the Hubbard Model: The Attractive Route
Authors: A. F. Ho, M. A. Cazalilla, T. Giamarchi
Categories: cond-mat.str-el
Comments: 11 pages, 5 figs
   We study the conditions under which, using a canonical transformation, the
phases sought after for the repulsive Hubbard model, namely a Mott insulator in
the paramagnetic and anti-ferromagnetic phases, and a putative d-wave
superfluid can be deduced from observations in an optical lattice loaded with a
spin-imbalanced ultra-cold Fermi gas with attractive interactions, thus
realizing the attractive Hubbard model. We show that the Mott insulator and
antiferromagnetic phase of the repulsive Hubbard model are in fact more easy to
observe as a paired, and superfluid phase respectively, in the attractive
Hubbard model. The putative d-wave superfluid phase of the repulsive Hubbard
model doped away from half-filling is related to a d-wave antiferromagnetic
phase for the attractive Hubbard model. We discuss the advantages of this
approach to 'quantum simulate' the Hubbard model in an optical lattice over the
approach that attempts to directly simulate the doped Hubbard model in the
repulsive regime. We also point out a number of technical difficulties of the
proposed approach and, in some cases, suggest possible solutions.
\\ ( , 196kb)
Date: Tue, 23 Dec 2008 20:11:07 GMT (102kb)

Title: Non-local pair correlations in the 1D Bose gas at finite temperature
Authors: P. Deuar, A. G. Sykes, D. M. Gangardt, M. J. Davis, P. D. Drummond,
   and K. V. Kheruntsyan
Categories: cond-mat.other
Comments: 22 pages, 13 figures
   The behavior of the spatial two-particle correlation function is surveyed in
detail for a uniform 1D Bose gas with repulsive contact interactions at finite
temperatures. Both long-, medium-, and short-range effects are investigated.
The results span the entire range of physical regimes, from ideal gas, to
strongly interacting, and from zero temperature to high temperature. We present
perturbative analytic methods, available at strong and weak coupling, and
first-principle numerical results using imaginary time simulations with the
gauge-P representation in regimes where perturbative methods are invalid.
Nontrivial effects are observed from the interplay of thermally induced
bunching behavior versus interaction induced antibunching.
\\ ( , 102kb)
Date: Mon, 22 Dec 2008 01:27:39 GMT (35kb)

Title: Detection of quantum orders of ultracold atoms in optical lattices by
   off-resonant scattering of cavity photons
Authors: Jinwu Ye, Jiangming Zhang, Wuming Liu, Keye Zhang, Yan Li, Zhe-Yu Ou
   and Weiping Zhang
Categories: physics.atom-ph cond-mat.str-el physics.optics
   We show that cavity enhanced off-resonant light scattering from ultra-cold
atoms loaded on optical lattices can detect the nature of quantum phases such
as the ground state, the excitation spectrum of these quantum phases and also
the universality class of any possible second order quantum phase transitions
between these phases. These quantum phases include not only the well known
superfluid and Mott insulating phases and the superfluid to Mott transition,
but also exotic phases such as charge density wave, valence bond solid and
several kinds of supersolids in one, two and three dimensional optical lattices
and quantum phases transitions between these phases. We also address how the
quantum information encoded in these quantum phases of matter can be
transferred to the light.
\\ ( , 35kb)
Date: Tue, 23 Dec 2008 12:24:18 GMT (124kb,D)

Title: Entanglement and the Mott insulator - superfluid phase transition in
   bosonic atom chains
Authors: R. J. Costa Farias, M. C. de Oliveira
Categories: quant-ph
Comments: 4 pages, 3 figures
   We analyze the developing of bipartite and multipartite entanglement through
the Mott-Insulator - Superfluid quantum phase transition. Starting from a Mott
insulator state, where a filling factor $\nu = N/M = 1$ per lattice site is
considered, we derive an exact expression for a completely connected graph
configuration of bosons and show how bipartite and multipartite entanglement
signals the phase transition predicted in previous works. Moreover, through the
transition bipartite entanglement shows to be monogamous.
\\ ( , 124kb)
Date: Tue, 23 Dec 2008 12:57:47 GMT (368kb,D)

Title: Generalized Purity and Quantum Phase Transition for Bose-Einstein
   condensates in a Symmetric Double Well
Authors: Thiago F. Viscondi, K. Furuya, M.C. de Oliveira
Categories: quant-ph
Comments: 4 pages, 4 figures
   The generalized purity is employed for investigating the process of coherence
loss and delocalization of the Q-function in the Bloch sphere of a two-mode
Bose-Einstein condensate in a symmetrical double well with cross-collision.
Quantum phase transition of the model is signaled by the generalized purity as
a function of an appropriate parameter of the Hamiltonian and the number of
particles (N). A power law dependence of the critical parameter with N is
\\ ( , 368kb)
Date: Mon, 22 Dec 2008 21:45:20 GMT (2400kb)

Title: Impact of Electric Fields on Highly Excited Rovibrational States of
   Polar Dimers
Authors: Rosario Gonzalez-Ferez and Peter Schmelcher
Categories: physics.atom-ph
Comments: 10 pages, 4 figures
   We study the effect of a strong static homogeneous electric field on the
highly excited rovibrational levels of the LiCs dimer in its electronic ground
state. Our full rovibrational investigation of the system includes the
interaction with the field due to the permanent electric dipole moment and the
polarizability of the molecule. We explore the evolution of the states next to
the dissociation threshold as the field strength is increased. The rotational
and vibrational dynamics are influenced by the field; effects such as
orientation, angular motion hybridization and squeezing of the vibrational
motion are demonstrated and analyzed. The field also induces avoided crossings
causing a strong mixing of the electrically dressed rovibrational states.
Importantly, we show how some of these highly excited levels can be shifted to
the continuum as the field strength is increased, and reversely how two atoms
in the continuum can be brought into a bound state by lowering the electric
field strength.
\\ ( , 2400kb)
Date: Tue, 23 Dec 2008 08:22:34 GMT (1315kb)

Title: Direct evaporative cooling of 41K into a Bose-Einstein condensate
Authors: T. Kishimoto, J. Kobayashi, K. Noda, K. Aikawa, M. Ueda, and S. Inouye
Categories: physics.atom-ph
Comments: 4 pages, 4 figures
   We have investigated the collisional properties of 41K atoms at ultracold
temperature. To show the possibility to use 41K as a coolant, a Bose-Einstein
condensate of 41K atoms in the stretched state (F=2, m_F=2) was created for the
first time by direct evaporation in a magnetic trap. An upper bound of three
body loss coefficient for atoms in the condensate was determined to be 4(2)
10^{-29} cm -6 s-1. A Feshbach resonance in the F=1, m_F=-1 state was observed
at 51.42(5) G, which is in good agreement with theoretical prediction.
\\ ( , 1315kb)
Date: Tue, 23 Dec 2008 09:23:57 GMT (89kb)

Title: Radio-frequency association of molecules: the dressed state picture
Authors: Q. Beaufils, A. Crubellier, T. Zanon, B. Laburthe-Tolra, E. Marechal,
   L. Vernac, O. Gorceix
Categories: physics.atom-ph
Comments: 4 pages, 2 figures
   We develop a theoretical model to describe the radio-frequency (rf) induced
coupling of a pair of colliding atoms to a Feshbach molecule when a magnetic
field arbitrarily far from the Feshbach resonance is modulated in time. We use
the dressed atom picture, and show that the coupling strength in presence of rf
is equal to the Feshbach coupling strength multiplied by the square of a Bessel
function. The argument of this function is equal to the ratio of the atomic rf
Rabi frequency to the rf frequency. We experimentally demonstrate this law by
measuring the rate of rf-association of molecules using a Feshbach resonance in
d-wave collisions between ultra-cold chromium atoms.
\\ ( , 89kb)
Date: Tue, 23 Dec 2008 16:36:50 GMT (1881kb)

Title: A large sample study of spin relaxation and magnetometric sensitivity of
   paraffin-coated Cs vapor cells
Authors: N. Castagna, G. Bison, G. Di Domenico, A. Hofer, P. Knowles, C.
   Macchione, A. Weis
Categories: physics.atom-ph physics.optics
   We have manufactured more than 250 nominally identical paraffin-coated Cs
vapor cells (30 mm diameter bulbs) for multi-channel atomic magnetometer
applications. We describe our dedicated cell characterization apparatus. For
each cell we have determined the intrinsic longitudinal, $\sGamma{01}$, and
transverse, $\sGamma{02}$, relaxation rates. Our best cell shows
$\sGamma{01}/2\pi\approx 0.5 Hz, and $\sGamma{02}/2\pi\approx 2 Hz. We find a
strong correlation of both relaxation rates which we explain in terms of
reservoir and spin exchange relaxation. For each cell we have determined the
optimal combination of rf and laser powers which yield the highest sensitivity
to magnetic field changes. Out of all produced cells, 90% are found to have
magnetometric sensitivities in the range of 9 to 30 fTHz. Noise analysis shows
that the magnetometers operated with such cells have a sensitivity close to the
fundamental photon shot noise limit.
\\ ( , 1881kb)
Date: Wed, 24 Dec 2008 02:13:38 GMT (14kb)

Title: Feshbach molecule production in fermionic atomic gases
Authors: V. Gurarie
Categories: cond-mat.other cond-mat.supr-con
Comments: 4 pages
   This paper examines the problem of molecule production in an atomic fermionic
gas close to an s-wave Feshbach resonance by means of a magnetic field sweep
through the resonance. The density of molecules at the end of the process is
derived for narrow resonance and slow sweep.
\\ ( , 14kb)
Date: Wed, 24 Dec 2008 12:52:50 GMT (936kb)

Title: Exploring correlated 1D Bose gases from the superfluid to the
   Mott-insulator state by inelastic light scattering
Authors: D. Cl\'ement, N. Fabbri, L. Fallani, C. Fort and M. Inguscio
Categories: cond-mat.other
Comments: 5 pages, 4 figures
   We report the Bragg spectroscopy of interacting one-dimensional Bose gases
loaded in optical lattices across the superfluid to Mott-insulator phase
transition. Elementary excitations are created with a non-zero momentum and the
response of the correlated 1D gases is in the linear regime. The complexity of
the strongly correlated quantum phases is directly displayed in the spectra
which exhibit novel features. This work paves the way for a precise
characterization of the state of correlated atomic phases in optical lattices.
\\ ( , 936kb)
Date: Wed, 24 Dec 2008 17:37:25 GMT (824kb)

Title: Effective field theory for spinor dipolar Bose Einstein condensates
Authors: M. Takahashi (Okayama University), Sankalpa Ghosh (I. I. T. Delhi), T.
   Mizushima (Okayama University), and K. Machida (Okayama University)
Categories: cond-mat.stat-mech cond-mat.mes-hall
Comments: Latex + 3 eps figures, accepted for publication in a special issue of
   EPJB on "Novel Quantum Phases and Mesoscopic Physics in Quantum Gases"
   We show that the effective theory of long wavelength low energy behavior of a
dipolar Bose-Einstein condensate(BEC) with large dipole moments (treated as a
classical spin) can be modeled using an extended Non-linear sigma model (NLSM)
like energy functional with an additional non-local term that represents long
ranged anisotropic dipole-dipole interaction. Minimizing this effective energy
functional we calculate the density and spin-profile of the dipolar
Bose-Einstein condensate in the mean-field regime for various trapping
geometries. The resulting configurations show strong intertwining between the
spin and mass density of the condensate, transfer between spin and orbital
angular momentum in the form of Einstein-de Hass effect, and novel topological
properties. We have also described the theoretical framework in which the
collective excitations around these mean field solutions can be studied and
discuss some examples qualitatively.
\\ ( , 824kb)

The replacements:

replaced with revised version Fri, 19 Dec 2008 11:16:56 GMT (380kb)

Title: Wigner crystal vs. Friedel oscillations in the 1D Hubbard model
Authors: Stefan A. Soeffing, Michael Bortz, Imke Schneider, Alexander Struck,
   Michael Fleischhauer and Sebastian Eggert
Categories: cond-mat.str-el cond-mat.mes-hall cond-mat.other
Comments: 5 pages, 4 figures, The most recent version can be found at Completely rewritten
   version and different title/author list
\\ ( , 380kb)
replaced with revised version Fri, 19 Dec 2008 04:08:04 GMT (247kb)

Title: Formation and Transformation of Vector-Solitons in Two-Species
   Bose-Einstein Condensates with Tunable Interaction
Authors: Xunxu Liu, Han Pu, Bo Xiong, W. M. Liu, Jiangbin Gong
Categories: cond-mat.other
Comments: to appear in Physical Review A
\\ ( , 247kb)
replaced with revised version Fri, 19 Dec 2008 11:54:09 GMT (1246kb)

Title: The Fluctuation Theorem and Relaxation to Equilibrium
Authors: Denis J. Evans, Debra J. Searles and Stephen R. Williams
Categories: cond-mat.stat-mech
Comments: 16 pages, no figures
\\ ( , 1246kb)
replaced with revised version Fri, 19 Dec 2008 12:14:10 GMT (1723kb)

Title: The Einstein-Podolsky-Rosen paradox: from concepts to applications
Authors: M. D. Reid, P. D. Drummond, E. G. Cavalcanti, W. P. Bowen, P. K. Lam,
   H. A. Bachor, U. L. Andersen, G. Leuchs
Categories: quant-ph
Comments: Colloquium in press in Reviews of Modern Physics, accepted Dec 2008
\\ ( , 1723kb)
replaced with revised version Fri, 19 Dec 2008 14:48:57 GMT (830kb)

Title: Spin squeezing in a bimodal condensate: spatial dynamics and particle
Authors: Yun Li (LKB - Lhomond, ECNU), Philipp Treutlein, Jakob Reichel (LKB -
   Lhomond), Alice Sinatra (LKB - Lhomond)
Categories: quant-ph
Comments: 18 pages, 13 figures. Accepted for publication in European Physical
   Journal B
\\ ( , 830kb)
replaced with revised version Mon, 22 Dec 2008 05:31:22 GMT (653kb)

Title: Bragg spectroscopy of a strongly interacting Fermi gas
Authors: G. Veeravalli, E. Kuhnle, P. Dyke, and C. J. Vale
Categories: cond-mat.other
Comments: Replaced with published version
Journal-ref: Phys. Rev. Lett. 101, 250403 (2008)
DOI: 10.1103/PhysRevLett.101.250403
\\ ( , 653kb)
replaced with revised version Mon, 22 Dec 2008 07:13:30 GMT (70kb)

Title: Semilinear response for the heating rate of cold atoms in vibrating
Authors: A. Stotland, D. Cohen, N. Davidson
Categories: quant-ph cond-mat.mes-hall
Comments: 7 pages, 6 figures, improved version
\\ ( , 70kb)
replaced with revised version Sat, 20 Dec 2008 20:03:38 GMT (1999kb)

Title: Superconductivity close to the Mott state: From condensed-matter systems
   to superfluidity in optical lattices
Authors: Karyn Le Hur and T. Maurice Rice
Categories: cond-mat.supr-con cond-mat.str-el
Comments: 97 pages and 18 figures
\\ ( , 1999kb)
replaced with revised version Tue, 23 Dec 2008 21:14:27 GMT (371kb)

Title: Fluctuations of a weakly interacting Bose-Einstein condensate
Authors: Z. Idziaszek, L. Zawitkowski, M. Gajda, K. Rzazewski
Categories: cond-mat.stat-mech
Comments: 4 pages, 4 figures; vastly improved version, now includes thermal
   atom interactions for the condensate statistics
\\ ( , 371kb)

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,        
Matt's arXiv selection: weekly summary of cold-atom papers from
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 Wed Feb 25 2009 - 08:31:33 EST

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