Matt's (belated) arXiv selection, Wednesday 3 May 2005.

From: Matthew Davis <>
Date: Wed, 3 May 2006 08:47:24 +1000 (EST)

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

Hi all,

My apologies for the delay this week ... all arXiv submissions up until
yesterday are included.

BTW - I am slightly paranoid that I might miss the odd abstract here and there.
If you think I have missed something of interest to the community, please let me
know and I will include it in the following week.


Paper: cond-mat/0604495
Date: Thu, 20 Apr 2006 21:14:28 GMT (18kb)

Title: Magnetic phase diagram of a frustrated ferrimagnetic ladder: Relation to
  the one-dimensional boson Hubbard model
Authors: N. B. Ivanov and J. Richter
Comments: 4 pages, 2 figures
Subj-class: Strongly Correlated Electrons
Journal-ref: Phys. Rev. B 73, 132407 (2006)
DOI: 10.1103/PhysRevB.73.132407
  We study the magnetic phase diagram of two coupled mixed-spin $(1,{1/2})$
Heisenberg chains as a function of the frustration parameter related to
diagonal exchange couplings. The analysis is performed by using spin-wave
series and exact numerical diagonalization techniques. The obtained phase
diagram--containing the Luttinger liquid phase, the plateau phase with a
magnetization per rung $M=1/2$, and the fully polarized phase--is closely
related to the generic $(J/U,\mu/U)$ phase diagram of the one-dimensional boson
Hubbard model.
\\ ( , 18kb)
Paper: cond-mat/0604500
Date: Fri, 21 Apr 2006 19:45:56 GMT (88kb)

Title: An epsilon expansion for Fermi gas at infinite scattering length
Authors: Yusuke Nishida and Dam Thanh Son
Comments: 4 pages, 4 figures, revtex4
Report-no: INT-PUB 06-08, TKYNT-06-06
Subj-class: Other
  We show that there exists a systematic expansion around four spatial
dimensions for Fermi gas in the unitarity regime. We perform the calculations
to leading and next-to-leading orders in the expansion over epsilon=4-d, where
d is the dimensionality of space. We find the ratio of chemical potential and
Fermi energy to be mu/epsilon_F=1/2 epsilon^3/2 + 1/16 epsilon^5/2 ln epsilon
-0.0246 epsilon^5/2 and the ratio of the gap in the fermion quasiparticle
spectrum and the chemical potential to be Delta/mu=2/epsilon-0.691. The minimum
of the fermion dispersion curve is located at |p|=(2m epsilon_0)^1/2 where
epsilon_0/mu=2+O(epsilon). Extrapolation to d=3 gives results consistent with
Monte Carlo simulations.
\\ ( , 88kb)
Paper: cond-mat/0604505
Date: Fri, 21 Apr 2006 08:16:45 GMT (106kb)

Title: Cyclic phase in F=2 spinor condensate: long-range order, kinks, and
  roughening transition
Authors: W. V. Pogosov, K. Machida
Comments: 6 pages, 1 figure
Subj-class: Statistical Mechanics
  We study the effect of thermal fluctuations on homogeneous infinite
Bose-Einstein condensate with spin F=2 in the cyclic state, when atoms occupy
three hyperfine states with $m_{F}=0, \pm 2$. We use both the approach of
small-amplitude oscillations and mapping of our model on the sine-Gordon model.
We show that thermal fluctuations lead to the existence of the rough phase in
one- and two-dimensional systems, when presence of kinks is favorable. The
structure and energy of a single kink are found. We also discuss the effect of
thermal fluctuations on spin degrees of freedom in F=1 condensate.
\\ ( , 106kb)
Paper: cond-mat/0604509
Date: Fri, 21 Apr 2006 10:19:26 GMT (121kb)

Title: Bose-Einstein Condensation Picture of Superconductivity in High
  Temperature Superconductors (Dilute Metals)
Authors: V.N.Bogomolov
Comments: 5 pages, 5 figures
Subj-class: Superconductivity
  Structures and parameters of some high and low temperature superconductors
(HTSC, LTSC) are considered basing on the alternative estimate of the O2- ion
radius magnitude (0.5-0.6) A. Phase transitions into the superconducting state
are considered as the Bose-Einstein condensation (BEC). The super HTSC with Tc
= 371 K (YBa2Cu3Se7) and TC ~ 400K (Ag2(Ag3Pb2H2O6)) and LTSC with Tc~0.3K
(SrNbxTi(1-x)O3) are shown to be of the BEC type. Instability of the structure
of the first one results from higher magnitude of the Se2- ion radius in
comparison with the O2- radius. The second one forms quasi one-dimensional
structures and is rather inpractical. The electron density and the effective
mass are estimated for some stoichiometric and non-stoichiometric
(nano-composite) high temperature superconductors, which have some peculiar
features. Large effective masses can indicate existance of polarons
(bipolarons) in such systems. Some new superconductors MgxWO3.
\\ ( , 121kb)
Paper (*cross-listing*): nlin.PS/0604044
Date: Thu, 20 Apr 2006 16:03:24 GMT (151kb)

Title: Oblique spatial dark solitons in supersonic flow of Bose-Einstein
Authors: G.A. El, A. Gammal, A.M. Kamchatnov
Comments: 4 pages, 3 figures
Subj-class: Pattern Formation and Solitons; Soft Condensed Matter
  In framework of the Gross-Pitaevskii mean field approach it is shown that
supersonic flow of Bose-Einstein condensate can support a new type of
pattern--an oblique spatial dark soliton. Exact spatial dark soliton solution
of the Gross-Pitaevskii equation is obtained. It is demonstrated by numerical
simulations that spatial solitons can be generated by an obstacle inserted into
the flow. Connection of the developed theory with available experimental data
is discussed.
\\ ( , 151kb)
Paper: quant-ph/0604158
Date: Thu, 20 Apr 2006 21:06:08 GMT (846kb)

Title: Semiclassical approach to Bose-Einstein condensates in a triple well
Authors: S. Mossmann, C. Jung
Comments: 15 pages, 15 figures
  We present a new approach for the analysis of Bose-Einstein condensates in a
few mode approximation. This method has already been used to successfully
analyze the vibrational modes in various molecular systems and offers a new
perspective on the dynamics in many particle bosonic systems. We discuss a
system consisting of a Bose-Einstein condensate in a triple well potential.
Such systems correspond to classical Hamiltonian systems with three degrees of
freedom. The semiclassical approach allows a simple visualization of the
eigenstates of the quantum system referring to the underlying classical
dynamics. From this classification we can read off the dynamical properties of
the eigenstates such as particle exchange between the wells and entanglement
without further calculations. In addition, this approach offers new insights
into the validity of the mean-field description of the many particle system by
the Gross-Pitaevskii equation, since we make use of exactly this correspondence
in our semiclassical analysis. We choose a three mode system in order to
visualize it easily and, moreover, to have a sufficiently interesting
structure, although the method can also be extended to higher dimensional
\\ ( , 846kb)
Paper: quant-ph/0604165
Date: Fri, 21 Apr 2006 16:39:50 GMT (141kb)

Title: Entanglement of orbital angular momentum states between an ensemble of
  cold atoms and a photon
Authors: R. Inoue, N. Kanai, T. Yonehara, Y. Miyamoto, M. Koashi and M. Kozuma
Comments: 12 pages, 3 figures
  Various atom-photon entangled states can be generated by utilizing
corresponding conservation law. In particular, higher-dimensional entanglement
between an atomic ensemble and a photon is expected to arise from angular
momentum conservation law. Here we demonstrate entanglement of orbital angular
momentum states by utilizing atomic collective excitation and Laguerre-Gaussian
modes of light. Generation of higher-dimensional entanglement between remote
atomic ensembles and an application to condensed matter physics are also
\\ ( , 141kb)
Paper (*cross-listing*): cond-mat/0604464
Date: Wed, 19 Apr 2006 23:23:40 GMT (117kb)

Title: Quantum theory of an atom laser originating from a Bose-Einstein
  condensate or a Fermi gas in the presence of gravity
Authors: Tobias Kramer and Mirta Rodriguez
Comments: 12 pages, 8 figures
Subj-class: Other; Atomic Physics
  We present a 3D quantum mechanical theory of radio-frequency outcoupled atom
lasers from trapped atomic gases in the presence of the gravitational force.
Predictions for the total outcoupling rate as a function of the radio-frequency
and for the beam wave function are given. We establish a sum rule for the
energy integrated outcoupling, which leads to a separate determination of the
coupling strength between the atoms and the radiation field.
  For a non-interacting Bose-Einstein condensate analytic solutions are derived
which are subsequently extended to include the effects of atomic interactions.
The interactions enhance interference effects in the beam profile and modify
the outcoupling rate of the atom laser. We provide a complete quantum
mechanical solution which is in line with experimental findings and allows to
determine the validity of commonly used approximative methods.
  We also extend the formalism to a fermionic atom laser and analyze the effect
of superfluidity on the outcoupling of atoms.
\\ ( , 117kb)
Paper: quant-ph/0601163
replaced with revised version Fri, 21 Apr 2006 10:22:24 GMT (620kb)

Title: Trapping atoms on a transparent permanent-magnet atom chip
Authors: A. Shevchenko, M. Heilio, T. Lindvall, A. Jaakkola, I. Tittonen, M.
  Kaivola, T. Pfau
Comments: Modifications: A) Reference I. Barb et al., Eur. Phys. JD, 35, 75
  (2005) added. B)Sentence rewritten: We routinely capture more than 10^6 atoms
  in a micro-MOT on a magnetized pattern. C) The magnetic field strengths are
  now given in Teslas. D) The second sentence in the fourth paragraph has been
  rewritten in order to more clearly describe the geometry and purpose of the
  compensation coils.E) In the seventh paragraph we have rewritten the sentence
  about the creation of the external magnetic field for the magnetic-domain
  patterning. F) In the ninth paragraph, we clarify the way to shift the trap
  center. G) Caption of Fig. 4 changed. H) We have modified paragraph 12 to
  improve the description on the guiding of the trap center along a toroidal
  pattern. I) The last two sentences of the manuscript have been rewritten
\\ ( , 620kb)
Paper: physics/0604169
Date: Fri, 21 Apr 2006 18:46:55 GMT (99kb)

Title: Resonant electric dipole-dipole interactions between cold Rydberg atoms
  in a magnetic field
Authors: K. Afrousheh, P. Bohlouli-Zanjani, J. D. Carter, A. Mugford, J. D. D.
Comments: Accepted for publication in Physical Review A
Subj-class: Atomic Physics
  Laser cooled Rb atoms were optically excited to 46d Rydberg states. A
microwave pulse transferred a fraction of the atoms to the 47p Rydberg state.
The resonant electric dipole-dipole interactions between atoms in these two
states were probed using the linewidth of the two-photon microwave transition
46d-47d. The presence of a weak magnetic field (approximately 0.5 G) reduced
the observed line broadening, indicating that the interaction is suppressed by
the field. The field removes some of the energy degeneracies responsible for
the resonant interaction, and this is the basis for a quantitative model of the
resulting suppression. A technique for the calibration of magnetic field
strengths using the 34s-34p one-photon transition is also presented.
\\ ( , 99kb)
Paper: nlin.PS/0604045
Date: Thu, 20 Apr 2006 16:53:49 GMT (257kb)
Date (revised v2): Thu, 20 Apr 2006 20:14:13 GMT (257kb)

Title: Coexistence of Josephson oscillations and novel self-trapping regime in
  optical waveguide arrays
Authors: Ramaz Khomeriki, Jerome Leon, Stefano Ruffo
Comments: 4 pages, 4 figures
Subj-class: Pattern Formation and Solitons; Statistical Mechanics; Optics
  Considering the coherent nonlinear dynamics between two weakly linked optical
waveguide arrays, we find the first example of coexistence of Josephson
oscillations with a novel self-trapping regime. This macroscopic bistability is
explained by proving analytically the simultaneous existence of symmetric,
antisymmetric and asymmetric stationary solutions of the associated
Gross-Pitaevskii equation. The effect is, moreover, illustrated and confirmed
by numerical simulations. This property allows to conceive an optical switch
based on the variation of the refractive index of the linking central
\\ ( , 257kb)
Paper: cond-mat/0604522
Date: Mon, 24 Apr 2006 12:45:06 GMT (885kb)

Title: A quantitative study of spin noise spectroscopy in a classical gas of
  $^{41}$K atoms
Authors: Bogdan Mihaila, Scott A. Crooker, Dwight G. Rickel, Krastan B.
  Blagoev, Peter B. Littlewood, and Darryl L. Smith
Report-no: LA-UR-06-2838
Subj-class: Other
  We present a general derivation of the electron spin noise power spectrum in
alkali gases as measured by optical Faraday rotation, which applies to both
classical gases at high temperatures as well as ultracold quantum gases. We
show that the spin-noise power spectrum is determined by an electron spin-spin
correlation function, and we find that measurements of the spin-noise power
spectra for a classical gas of $^{41}$K atoms are in good agreement with the
predicted values. Experimental and theoretical spin noise spectra are directly
and quantitatively compared in both longitudinal and transverse magnetic fields
up to the high magnetic field regime (where Zeeman energies exceed the
intrinsic hyperfine energy splitting of the $^{41}$K ground state).
\\ ( , 885kb)
Paper: cond-mat/0604525
Date: Sat, 22 Apr 2006 11:10:54 GMT (86kb)

Title: Deconfinement and cold atoms in optical lattices
Authors: M. A. Cazalilla, A. F. Ho and T. Giamarchi
Comments: Proceedings of the conference on "Quantum Many Body Theories 13", to
  be published by World Scientific
Subj-class: Strongly Correlated Electrons; Superconductivity
  Despite the fact that by now one dimensional and three dimensional systems of
interacting particles are reasonably well understood, very little is known on
how to go from the one dimensional physics to the three dimensional one. This
is in particular true in a quasi-one dimensional geometry where the hopping of
particles between one dimensional chains or tubes can lead to a dimensional
crossover between a Luttinger liquid and more conventional high dimensional
states. Such a situation is relevant to many physical systems. Recently cold
atoms in optical traps have provided a unique and controllable system in which
to investigate this physics. We thus analyze a system made of coupled one
dimensional tubes of interacting fermions. We explore the observable
consequences, such as the phase diagram for isolated tubes, and the possibility
to realize unusual superfluid phases in coupled tubes systems.
\\ ( , 86kb)
Paper: cond-mat/0604530
Date: Sun, 23 Apr 2006 10:06:37 GMT (99kb)

Title: Asymmetric Fermi superfluid in a harmonic trap
Authors: C.-H. Pao and S.-K. Yip
Comments: 15 pages, 5 figures
Subj-class: Other; Superconductivity
  We consider a dilute two-component atomic fermion gas with unequal
populations in a harmonic trap potential using the mean field theory and the
local density approximation. We show that the system is phase separated into
concentric shells with the superfluid in the core surrounded by the normal
fermion gas in both the weak-coupling BCS side and near the Feshbach resonance.
In the strong-coupling BEC side, the composite bosons and left-over fermions
can be mixed. We calculate the cloud radii and compare axial density profiles
systemically for the BCS, near resonance and BEC regimes.
\\ ( , 99kb)
Paper: cond-mat/0604550
Date: Mon, 24 Apr 2006 15:10:55 GMT (33kb)

Title: Condensation temperature of interacting Bose gases with and without
Authors: O. Zobay
Comments: 7 pages, 2 figures
Subj-class: Statistical Mechanics
Journal-ref: Phys. Rev. A 73, 023616 (2006)
DOI: 10.1103/PhysRevA.73.023616
  The momentum-shell renormalization group (RG) is used to study the
condensation of interacting Bose gases without and with disorder. First of all,
for the homogeneous disorder-free Bose gas the interaction-induced shifts in
the critical temperature and chemical potential are determined up to second
order in the scattering length. The approach does not make use of dimensional
reduction and is thus independent of previous derivations. Secondly, the RG is
used together with the replica method to study the interacting Bose gas with
delta-correlated disorder. The flow equations are derived and found to reduce,
in the high-temperature limit, to the RG equations of the classical
Landau-Ginzburg model with random-exchange defects. The random fixed point is
used to calculate the condensation temperature under the combined influence of
particle interactions and disorder.
\\ ( , 33kb)
Paper: cond-mat/0404577
replaced with revised version Mon, 24 Apr 2006 08:42:33 GMT (45kb)

Title: Deformed Fermi surfaces in ultracold Fermi gases
Authors: Armen Sedrakian, Jordi Mur-Petit, Artur Polls, Herbert M\"uther
Comments: v1: 12 pages, including 3 figures; v2: 5 pages, 3 figures, minor
  corrections. See cond-mat/0504511 for the expanded work
Subj-class: Superconductivity
\\ ( , 45kb)
Paper: cond-mat/0604557
Date: Mon, 24 Apr 2006 20:02:41 GMT (140kb)

Title: Stable skyrmions in spinor condensates
Authors: Igor F. Herbut and Masaki Oshikawa
Comments: 4 pages, 2 figures
Subj-class: Superconductivity; Statistical Mechanics
  Globally symmetric spinor condensates in free space are argued not to support
stable topological defects in either two or three dimensions. In the latter
case, however, we show that a topological skyrmion can be stabilized by forcing
it to adopt certain density profiles. A sufficient condition for the existence
of a stable skyrmion in three dimensions is formulated and illustrated in
simple examples. Our results pertain to Bose-Einstein condensation in Rb.
\\ ( , 140kb)
Paper: cond-mat/0604558
Date: Tue, 25 Apr 2006 15:08:53 GMT (940kb)

Title: Phase diagram of a polarized Fermi gas across a Feshbach resonance in a
  potential trap
Authors: W. Yi and L.-M. Duan
Comments: 9 pages, 4 figures
Subj-class: Other
  We map out the detailed phase diagram of a trapped ultracold Fermi gas with
population imbalance across a wide Feshbach resonance. We show that under the
local density approximation, the properties of the atoms in any (anisotropic)
harmonic traps are universally characterized by three dimensionless parameters:
the normalized temperature, the dimensionless interaction strength, and the
population imbalance. We then discuss the possible quantum phases in the trap,
and quantitatively characterize their phase boundaries in various typical
parameter regions.
\\ ( , 940kb)
Paper: cond-mat/0604565
Date: Tue, 25 Apr 2006 08:07:14 GMT (9kb)

Title: Quantum Depletion of a Soliton Condensate
Authors: Guoxiang Huang, L. Deng, Jiaren Yan, and Bambi Hu
Comments: 11 pages
Subj-class: Other
  We present rigorous results on the diagonalization of Bogoliubov Hamilto-
nian for a soliton condensate. Using the complete and orthonomalized set of
eigenfunction for the Bogoliubov de Gennes equations, we calculate ex- actly
the quantum depletion of the condensate and show that two degenerate
zero-modes, which originate from a U(1) guage- and a translational-symmetry
breaking of the system, induce the quantum diffusion and transverse instabil-
ity of the soliton condensate.
\\ ( , 9kb)
Paper: cond-mat/0604572
Date: Tue, 25 Apr 2006 12:07:45 GMT (78kb)

Title: Resonant pairing between Fermions with unequal masses
Authors: S.-T. Wu, C.-H. Pao and S.-K. Yip
Comments: 10 pages, 4 figures
Subj-class: Superconductivity; Other
  We study the pairing between Fermions of different masses, especially at the
unitary limit. At equal populations, the thermodynamic properties are identical
with the equal mass case provided an appropriate rescaling is made. At unequal
populations, for sufficiently light majority species, the system does not phase
separate. For sufficiently heavy majority species, the phase separated normal
phase have a density larger than that of the superfluid. For atoms in harmonic
traps, the density profiles for unequal mass Fermions can be drastically
different from their equal-mass counterparts.
\\ ( , 78kb)
Paper (*cross-listing*): nucl-th/0604053
Date: Fri, 21 Apr 2006 04:39:31 GMT (497kb)

Title: Universality in a 2-component Fermi System at Finite Temperature
Authors: Gautam Rupak
Comments: 10 pages, 6 figures, LaTeX2e
Report-no: INT PUB-06 5
Subj-class: Nuclear Theory; Statistical Mechanics
  Thermodynamic properties of a fermionic system close to the unitarity limit,
where the 2-body scattering length |a| approaches infinity is studied at high
temperature Boltzmann regime. For dilute systems the virial expansion
coefficients in the Boltzmann regime are expected, from general arguments, to
be universal. A model independent finite temperature T calculation of the third
virial coefficient b3(T) is presented. At the unitarity limit, b3(T) = -0.48 is
an universal number. The energy density up to the third virial expansion is
derived. These results are relevant for dilute neutron matter and could be
tested in current atomic experiments on dilute fermionic gases near the
Feshbach resonance.
\\ ( , 497kb)
Paper: cond-mat/0507399
replaced with revised version Tue, 25 Apr 2006 14:15:08 GMT (20kb)

Title: The unitary three-body problem in a trap
Authors: F\'{e}lix Werner (LKB - Lhomond), Yvan Castin (LKB - Lhomond)
Comments: 4 pages
Proxy: ccsd ccsd-00007574
Subj-class: Other
\\ ( , 20kb)
Paper: cond-mat/0508010
replaced with revised version Tue, 25 Apr 2006 07:40:29 GMT (34kb)

Title: Production efficiency of Feshbach molecules in fermion systems
Authors: B. E. Dobrescu, V. L. Pokrovsky
Comments: 4 pages, 1 figure
Subj-class: Statistical Mechanics
Journal-ref: Phys. Lett. A 350, 154 (2006)
DOI: 10.1016/j.physleta.2005.10.009
\\ ( , 34kb)
Paper: cond-mat/0604416
replaced with revised version Tue, 25 Apr 2006 06:57:14 GMT (337kb)

Title: Crossover States of Vortex Matter in Trapped Bose Condensates
Authors: S. Kragset, E. Babaev and A. Sudbo
Comments: v2: figure quality improved
Subj-class: Statistical Mechanics
\\ ( , 337kb)
Paper: cond-mat/0604580
Date: Tue, 25 Apr 2006 20:33:15 GMT (16kb)

Title: Superfluidity in a Three-flavor Fermi Gas with SU(3) Gauge Symmetry
Authors: Lianyi He, Meng Jin and Pengfei Zhuang (Tsinghua U.)
Comments: 10 pages, 2 figures
Subj-class: Other
  We investigate the superfluidity and the associated Nambu-Goldstone modes in
a three-flavor atomic Fermi gas with SU(3) gauge symmetry. The s-wave pairing
occurs in flavor anti-triplet channel due to the Pauli principle. The
superfluid state contains both gapped and gapless fermionic excitations, and
the SU(3) gauge symmetry group is spontaneously broken to a SU(2) subgroup.
Since five generators of SU(3) group are broken, we expect five Nambu-Goldstone
modes will appear. However, we only find three Nambu-Goldstone modes. One
Nambu-Goldstone mode has linear dispersion law and the other two
Nambu-Goldstone mode have quadratic dispersion law. The additional two
collective modes obtain a mass gap. This mass gap is of order the energy gap of
fermions in a wide range of the coupling. The abnormal number of
Nambu-Goldstone modes, the quadratic dispersion law and the mass gap have
significant effect on the low temperature thermodynamics of the matter.
\\ ( , 16kb)
Paper: cond-mat/0604600
Date: Wed, 26 Apr 2006 17:47:36 GMT (367kb)

Title: High field fractional quantum Hall effect in optical lattices
Authors: R. N. Palmer, D. Jaksch
Comments: 4 pages, 4 figures, accepted by PRL
Subj-class: Mesoscopic Systems and Quantum Hall Effect
  We consider interacting bosonic atoms in an optical lattice subject to a
large simulated magnetic field. We develop a model similar to a bilayer
fractional quantum Hall system valid near simple rational numbers of magnetic
flux quanta per lattice cell. Then we calculate its ground state, magnetic
lengths, fractional fillings, and find unexpected sign changes in the Hall
current. Finally we study methods for detecting these novel features via shot
noise and Hall current measurements.
\\ ( , 367kb)
Paper: physics/0604061
replaced with revised version Tue, 25 Apr 2006 14:23:42 GMT (751kb)

Title: 6-axis inertial sensor using cold-atom interferometry
Authors: B. Canuel, F. Leduc, D. Holleville, A. Gauguet, J. Fils, A. Virdis, A.
  Clairon, N. Dimarcq, Ch. J. Borde, P. Bouyer, A. Landragin
Comments: submitted to PRL
Subj-class: Atomic Physics
\\ ( , 751kb)
Paper: cond-mat/0604625
Date: Thu, 27 Apr 2006 15:55:06 GMT (422kb)

Title: Signatures of the superfluid to Mott-insulator transition in the
  excitation spectrum of ultracold atoms
Authors: S.R. Clark and D. Jaksch
Comments: 17 pages and 11 figures
Subj-class: Other
  We present a detailed analysis of the dynamical response of ultra-cold
bosonic atoms in a one-dimensional optical lattice subjected to a periodic
modulation of the lattice depth. Following the experimental realization by
Stoferle et al [Phys. Rev. Lett. 92, 130403 (2004)] we study the excitation
spectrum of the system as revealed by the response of the total energy as a
function of the modulation frequency Omega. By using the Time Evolving Block
Decimation algorithm, we are able to simulate one-dimensional systems
comparable in size to those in the experiment, with harmonic trapping and
across many lattice depths ranging from the Mott-insulator to the superfluid
regime. Our results produce many of the features seen in the experiment, namely
a broad response in the superfluid regime, and narrow discrete resonances in
the Mott-insulator regime. We identify several signatures of the
superfluid-Mott insulator transition that are manifested in the spectrum as it
evolves from one limit to the other.
\\ ( , 422kb)
Paper: cond-mat/0509693
replaced with revised version Thu, 27 Apr 2006 19:39:12 GMT (29kb)

Title: Superfluidity without Symmetry-Breaking: The Time-Dependent Hartree-Fock
  Approximation for Bose-Condensed Systems
Authors: C.-H. Zhang and H.A. Fertig
Comments: 2 figure. Submitted to PRA
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\ ( , 29kb)
Paper: quant-ph/0604205
Date: Thu, 27 Apr 2006 15:25:58 GMT (721kb)

Title: Analytical solutions for the dynamics of two trapped interacting
  ultracold atoms
Authors: Zbigniew Idziaszek, Tommaso Calarco
Comments: RevTeX, 15 pages, 15 figures
  We discuss exact solutions of the Schroedinger equation for the system of two
ultracold atoms confined in an axially symmetric harmonic potential. We
investigate different geometries of the trapping potential, in particular we
study the properties of eigenenergies and eigenfunctions for quasi-one- and
quasi-two-dimensional traps. We show that the quasi-one- and the
quasi-two-dimensional regimes for two atoms can be already realized in the
traps with moderately large (or small) ratios of the trapping frequencies in
the axial and the transverse directions. Finally, we apply our theory to
Feshbach resonances for trapped atoms. Introducing in our description an
energy-dependent scattering length we calculate analytically the eigenenergies
for two trapped atoms in the presence of a Feshbach resonance.
\\ ( , 721kb)
Paper: physics/0604220
Date: Thu, 27 Apr 2006 17:31:48 GMT (313kb)

Title: Analysis of the atom-number correlation function in a few-atom trap
Authors: Youngwoon Choi, Seokchan Yoon, Sungsam Kang, Woongnae Kim, Jai-Hyung
  Lee, and Kyungwon An
Comments: 5 pages, 3 figures
Subj-class: Atomic Physics
  Stochastic properties of loading and loss mechanism in a few atom trap are
analyzed. An approximate formula is derived for the atom-number correlation
function for the trapped atoms in the limit of reasonably small two-atom loss
rate. Validity of the approximate formula is confirmed by numerical
\\ ( , 313kb)
Paper: cond-mat/0604638
Date: Fri, 28 Apr 2006 03:22:33 GMT (363kb)

Title: Surface tension in population imbalanced unitary Fermi gases
Authors: Theja N. De Silva, Erich J. Mueller
Comments: 4 pages, 4 figures
Subj-class: Other
  We study the effects of surface tension between normal and superfluid regions
of a trapped Fermi gas at unitarity. We find that surface tension causes
notable distortions in the shape of large aspect ratio clouds. Including these
distortions in our theories resolves many of the apparent discrepancies among
different experiments and between theory and experiments.
\\ ( , 363kb)
Paper: cond-mat/0604671
Date: Fri, 28 Apr 2006 16:30:48 GMT (677kb)

Title: Theory of Ultracold Superstrings
Authors: Michiel Snoek, S. Vandoren, and H.T.C. Stoof
Comments: 16 pages, 9 figures
Subj-class: Other
  The combination of a vortex line in a one-dimensional optical lattice with
fermions bound to the vortex core makes up an ultracold superstring. We give a
detailed derivation of the way to make this supersymmetric string in the
laboratory. In particular, we discuss the presence of a fermionic bound state
in the vortex core and the tuning of the laser beams needed to achieve
supersymmetry. Moreover, we discuss experimental consequences of supersymmetry
and identify the precise supersymmetry in the problem. Finally, we make the
mathematical connection with string theory.
\\ ( , 677kb)
Paper: cond-mat/0604673
Date: Fri, 28 Apr 2006 17:08:53 GMT (127kb)

Title: Evolution from a Bose-Einstein Condensate to a Tonks-Girardeau Gas: An
  Exact Diagonalization Study
Authors: Frank Deuretzbacher, Kai Bongs, Klaus Sengstock, Daniela Pfannkuche
Comments: 5 pages, 5 figures
Subj-class: Other
  We study ground state properties of spinless, quasi one-dimensional bosons
which are confined in a harmonic trap and interact via repulsive
delta-potentials. We use the exact diagonalization method to analyze the
pair-correlation function, as well as the density, the momentum distribution,
different contributions to the energy and the population of single particle
orbitals in the whole interaction regime. In particular, we are able to trace
the fascinating transition from bosonic to fermi-like behavior in
characteristic features of the momentum distribution which is accessible to
experiments. Our calculations yield quantitative measures for the interaction
strength limiting the mean-field regime on one side and the Tonks-Girardeau
regime on the other side of an intermediate regime.
\\ ( , 127kb)
Paper: quant-ph/0604214
Date: Fri, 28 Apr 2006 17:23:15 GMT (561kb)

Title: Wave-Particle Fluctuations, Coherence, and Bose-Einstein Condensation
Authors: N. M. Chase
  By extending Einstein's separation of wave and particle parts of the second
order thermal fluctuation to encompass "generalized fluctuations" in any Bose
field, P. E. Gordon has proposed alternative definitions for nth order
coherence and nth order coherent states. The main point of this paper is to
explore some of the physical insights to be gained by extending dualism to
higher orders. Recent experiments have examined aspects of the coherence of
Bose-Einstein condensates. It has been argued that the condensate state is
coherent to (at least) second or third order, but the coherence properties of
Bose-Einstein condensates remain somewhat controversial. Using probability
distributions developed by M. O. Scully and V. V. Kocharovsky et. al., we apply
Gordon's dualistic expression of the coherence conditions to investigate
coherence properties in Bose-Einstein condensation. Via numerical calculations,
we present a graphical survey of wave-like and particle-like fluctuations in
condensed and uncondensed fractions. Near the critical point, we find a very
marked peak in the ratio of nth order wave to nth order particle fluctuations
in the condensate. Not surprisingly, n-point correlations between the positions
of condensate atoms also peak near the critical temperature, and this
apparently mirrors, to higher orders, the well-known relation between the
integral of the 2-point correlation function over a certain volume and the rms
fluctuation in the number of particles in that volume.
\\ ( , 561kb)
Paper: cond-mat/0605005
Date: Mon, 1 May 2006 01:49:18 GMT (50kb)

Title: Phase Transition in Imbalanced Fermion Superfluids
Authors: Heron Caldas
Comments: This is an invited contribution to a book titled "Pairing beyond BCS
  Theory in Fermionic Systems" (Mark Alford, John Clark and Armen Sedrakian,
  eds.), to be published by World Scientific. 3 figures, 12 pages
Subj-class: Superconductivity
  In this chapter the recent theoretical work on phase transition in imbalanced
fermion superfluids is reviewed. The imbalanced systems are those in which the
two fermionic species candidate to form pairing have different Fermi surfaces
or densities. We consider systems subjected to weak interactions. In this
scenario two distinct phase transitions are predicted to occur. A
thermodynamical phase transition, induced by the temperature (T), and a quantum
phase transition as a function of the increasing chemical potentials asymmetry,
that takes place at zero temperature. We also briefly discuss some recent
experimental work at non-zero T with imbalanced Fermi gases in cold atomic
\\ ( , 50kb)
Paper: cond-mat/0605038
Date: Mon, 1 May 2006 18:06:15 GMT (211kb)

Title: The evolution of additional (hidden) quantum variables in the
  interference of Bose-Einstein condensates
Authors: W. J. Mullin, R. Krotkov, and F. Lalo\"{e}
Comments: 27 pages, 7 figures
Subj-class: Other
  Additional variables (also often called ``hidden variables'') are sometimes
added to standard quantum mechanics in order to remove its indeterminism or
``incompletness,'' and to make the measurement process look more classical.
Here we discuss a case in which an additional variable arises almost
spontaneously from the quantum formalism: the emergence of relative phase
between two highly populated Fock state Bose-Einstein condensates. The model
simulated here involves the interference of two Bose condensates, one with all
up spins, and the other with down spins, along a z-axis. With the clouds
overlapping, we consider the results of measuring spins in a transverse plane
(the general direction is studied in an appendix). The determination of the
previously ``hidden'' phase becomes progressively more definite as additional
measurements are made. We also provide an analysis of a recent and closely
related experiment.
\\ ( , 211kb)
Paper: cond-mat/0605039
Date: Mon, 1 May 2006 19:07:46 GMT (61kb)

Title: Intermediate temperature superfluidity in an atomic Fermi gas with
  population imbalance
Authors: Chih-Chun Chien, Qijin Chen, Yan He, and K. Levin
Comments: 4 pages, 4 EPS figures, submitted to PRL
Subj-class: Strongly Correlated Electrons; Superconductivity
  We derive the underlying finite temperature theory which describes Fermi gas
superfluidity in the presence of population imbalance. We address the behavior
of the pair formation and superfluid transition temperatures, and of the
superfluid density and thereby present a complete phase diagram for a
homogeneous system. In the fermionic regime, we show how thermal effects can
enhance pairing and stabilize the polarized superfluid phase away from T=0.
Importantly, at unitarity the polarized state is an ``intermediate temperature
\\ ( , 61kb)
Paper: cond-mat/0512134
replaced with revised version Fri, 28 Apr 2006 21:52:39 GMT (84kb)

Title: Acoustic attenuation probe for fermion superfluidity in ultracold atom
Authors: Sergio Gaudio (1)(2), B. Mihaila (2), K. B. Blagoev (2), K. S. Bedell
  (1), Eddy Timmermans (2) (1) (Department of Physics, Boston College) (2)
  (Theoretical Division, Los Alamos Natl Labs)
Comments: 4 pages, 2 figures. Revised version
Report-no: LAUR-05-3432
Subj-class: Other
\\ ( , 84kb)
Paper: quant-ph/0502011
replaced with revised version Fri, 28 Apr 2006 20:33:44 GMT (115kb)

Title: Deterministic Entanglement via Molecular Dissociation in Integrated Atom
Authors: Bo Zhao, Zeng-Bing Chen, Jian-Wei Pan, J. Schmiedmayer, Alessio
  Recati, Grigory E. Astrakharchik, Tommaso Calarco
Comments: 4 pages, 3 figures
Subj-class: Quantum Physics; Mesoscopic Systems and Quantum Hall Effect
\\ ( , 115kb)

Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email:
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Received on Wed May 03 2006 - 08:47:24 EST

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