# Matt's arXiV selection, Friday 23rd December 2005.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Fri, 23 Dec 2005 18:12:51 +1000 (EST)

Merry Xmas everyone!

Loads of papers this week. Make sure you email me if you want to
receive this email on a weekly basis.

Matt.

--
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Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email: mdavis_at_physics.uq.edu.au
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Australia.                    http://www.physics.uq.edu.au/people/mdavis/
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Paper: cond-mat/0512371
Date: Fri, 16 Dec 2005 10:00:22 GMT   (600kb)
Title: Permanent magnetic lattices for ultracold atoms and quantum degenerate
gases
Authors: Saeed Ghanbari, Tien D. Kieu, Andrei Sidorov and Peter Hannaford
Comments: 15 pages, 7 figures, to appear in Journal of Physics B: Atomic,
Molecular and Optical Physics
Subj-class: Other
\\
We propose the use of periodic arrays of permanent magnetic films for
producing magnetic lattices of microtraps for confining, manipulating and
controlling small clouds of ultracold atoms and quantum degenerate gases. Using
analytical expressions and numerical calculations we show that periodic arrays
of magnetic films can produce one-dimensional (1D) and two-dimensional (2D)
magnetic lattices with non-zero potential minima, allowing ultracold atoms to
be trapped without losses due to spin flips. In particular, we show that two
crossed layers of periodic arrays of parallel rectangular magnets plus bias
fields, or a single layer of periodic arrays of square-shaped magnets with
three different thicknesses plus bias fields, can produce 2D magnetic lattices
of microtraps having non-zero potential minima and controllable trap depth. For
arrays with micron-scale periodicity, the magnetic microtraps can have very
large trap depths ($\sim$0.5 mK for the realistic parameters chosen for the 2D
lattice) and very tight confinement.
\\ ( http://arXiv.org/abs/cond-mat/0512371 ,  593kb)
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Paper: cond-mat/0510634
replaced with revised version Fri, 16 Dec 2005 10:07:40 GMT   (61kb)
Title: Spin-3 Chromium Bose-Einstein Condensates
Authors: L. Santos and T. Pfau
Comments: 4 pages, 3 eps figures. Error in the previous version corrected
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0510634 ,  61kb)
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Paper: physics/0512151
Date: Fri, 16 Dec 2005 12:32:04 GMT   (300kb)
Title: Double-impulse magnetic focusing of launched cold atoms
Authors: Aidan S Arnold, Matthew J Pritchard, David A Smith and Ifan G Hughes
Subj-class: Atomic Physics; Optics
\\
We have theoretically investigated 3D focusing of a launched cloud of cold
atoms using a pair of magnetic lens pulses (the alternate-gradient method).
Individual lenses focus radially and defocus axially or vice-versa. We discuss
the performance of the two possible pulse sequences and find they are ideal for
loading both pancake' and sausage' shaped magnetic/optical microtraps. We
show that focusing aberrations are considerably smaller for double-impulse
magnetic lenses compared to single-impulse magnetic lenses.
\\ ( http://arXiv.org/abs/physics/0512151 ,  300kb)
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Paper: physics/0512149
Date: Fri, 16 Dec 2005 10:52:49 GMT   (20kb,H)
Title: Note on saturable absorption and 'slow light'
Comments: 11 pages 3 figures submitted to Optics Letters
Subj-class: Optics; General Physics
\\
Quantitative evaluation of some recent 'slow light' experiments shows that
they can be interpreted as saturable absorption phenomena and therefore do not
necessarily demonstrate a reductuion in the group velocity of light
\\ ( http://arXiv.org/abs/physics/0512149 ,  20kb)
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Paper: cond-mat/0512431
Date: Mon, 19 Dec 2005 02:34:39 GMT   (502kb)
Title: Characterisation of superfluid vortices in helium II
Authors: Gregory P. Bewley, Daniel P. Lathrop, and Katepalli R. Sreenivasan
Subj-class: Statistical Mechanics; Superconductivity
\\
Matter at low temperatures exhibits unusual properties such as superfluidity,
superconductivity, Bose-Einstein condensation, and supersolidity. These states
display quantum mechanical behaviours at scales much larger than atomic
dimensions. As in many phase transitions, defects can occur during the
transition to the low temperature state. The study of these defects yields
useful information about the nature of the transitions and of the macroscopic
states themselves. When cooled below the lambda temperature (~2.172 K), liquid
helium acquires superfluid properties, and the defects in the superfluid take
the form of line vortices with quantized circulation. The formation of these
vortices has been suggested as a model for cosmological structure formation.
Here we visualize these superfluid (or quantized) vortices by suspending
micron-sized solid particles of hydrogen in the fluid. The particles at low
concentrations arrange themselves with nearly equal spacing along vortex lines.
The number density of the vortex lines in a steadily rotating state compares
well with Feynman's prediction. For the first time, it is possible to observe
superfluid turbulence in which the superfluid vortices interact, and exist in
networks with complex branching. Our method makes it possible to characterize
the vortices during the transition across the lambda point and in the turbulent
state itself.
\\ ( http://arXiv.org/abs/cond-mat/0512431 ,  502kb)
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Paper: cond-mat/0512451
Date: Mon, 19 Dec 2005 13:40:16 GMT   (28kb)
Title: Classification of Light-Induced Desorption of Alkali Atoms in Glass
Cells Used in Atomic Physics Experiments
Authors: Atsushi Hatakeyama, Markus Wilde, Katsuyuki Fukutani
Comments: 6 pages, 1 figure, submitted to e-Journal of Surface Science and
Nanotechnology
Subj-class: Other
\\
We attempt to provide physical interpretations of light-induced desorption
phenomena that have recently been observed for alkali atoms on glass surfaces
of alkali vapor cells used in atomic physics experiments. We find that the
observed desorption phenomena are closely related to recent studies in surface
science, and can probably be understood in the context of these results. If
classified in terms of photon-energy dependence and the coverage and the
bonding state of the alkali adsorbates, the phenomena fall into two categories:
It appears very likely that the neutralization of isolated ionic adsorbates by
photo-excited electron transfer from the substrate is the origin of the
desorption induced by ultraviolet light in ultrahigh vacuum cells. The
desorption observed in low temperature cells, on the other hand, which is
resonantly dependent on photon energy in the visible light range, is quite
similar to light-induced desorption stimulated by localized electronic
excitation on metallic aggregates. More detailed studies of light-induced
desorption events from surfaces well characterized with respect to alkali
coverage-dependent ionicity and aggregate morphology appear highly desirable
for the development of more efficient alkali atom sources suitable to improve a
variety of atomic physics experiments.
\\ ( http://arXiv.org/abs/cond-mat/0512451 ,  28kb)
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Paper: cond-mat/0512460
Date: Mon, 19 Dec 2005 16:14:33 GMT   (19kb)
Title: Released momentum distribution of a Fermi gas in the BCS-BEC crossover
Authors: M.L. Chiofalo, S. Giorgini, M. Holland
Subj-class: Other
\\
We develop a time-dependent mean-field theory to investigate the released
momentum distribution and the released energy of an ultracold Fermi gas in the
BCS-BEC crossover after the scattering length has been set to zero by a fast
magnetic-field ramp. For a homogeneous gas we analyze the non-equilibrium
dynamics of the system as a function of the interaction strength and of the
ramp speed. For a trapped gas the theoretical predictions are compared with
experimental results.
\\ ( http://arXiv.org/abs/cond-mat/0512460 ,  19kb)
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Paper: cond-mat/0512472
Date: Mon, 19 Dec 2005 20:21:17 GMT   (64kb)
Title: Fermionic superfluidity with positive scattering length
Authors: Bout Marcelis and Servaas Kokkelmans
Subj-class: Statistical Mechanics; Superconductivity
\\
Superfluidity in an ultracold Fermi gas is usually associated with either a
negative scattering length, or the presence of a two-body bound state. We show
that none of these ingredients is necessary to achieve superfluidity. Using a
narrow Feshbach resonance with strong repulsive background interactions, the
effective interactions can be repulsive for small energies and attractive for
energies around the Fermi energy, similar to the effective interactions between
electrons in a metallic superconductor. This can result in BCS-type
superfluidity while the scattering length is positive.
\\ ( http://arXiv.org/abs/cond-mat/0512472 ,  64kb)
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Paper: cond-mat/0506210
replaced with revised version Mon, 19 Dec 2005 03:54:55 GMT   (61kb)
Title: Shock waves in a one-dimensional Bose gas: from a Bose-Einstein
condensate to a Tonks gas
Authors: Bogdan Damski
Comments: 10 pages, 5+ figures, 20% shorter than first version, new references,
many parts rewritten
Report-no: LAUR-05-4188
Subj-class: Other; Pattern Formation and Solitons; Quantum Physics
\\ ( http://arXiv.org/abs/cond-mat/0506210 ,  61kb)
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Paper: cond-mat/0509161
replaced with revised version Mon, 19 Dec 2005 08:49:23 GMT   (442kb)
Title: Extended Bose Hubbard model of interacting bosonic atoms in optical
lattices: from superfluidity to density waves
Authors: G. Mazzarella, S. M. Giampaolo, F. Illuminati
Comments: 18 pages, 7 figures, accepted for publication in Phys. Rev. A
Subj-class: Other; Statistical Mechanics; Atomic Physics; Quantum Physics
\\ ( http://arXiv.org/abs/cond-mat/0509161 ,  442kb)
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Paper: quant-ph/0512149
Date: Mon, 19 Dec 2005 01:01:27 GMT   (18kb)
Title: Coherent Molecular Output by Encoding Photons in an Atomic Bose
Condensate
Authors: Hui Jing and Ming-Sheng Zhan
\\
We study the quantum dynamics of coherent molecular output from an atomic
Bose-Einstein condensate via two-color photo-association by considering a
quantized associating light. Two different evolution regimes, the optical
transmission and the molecular output regimes are identified, and this
indicates a feasible scheme, even in the presence of atomic depletions, to
realize the quantum control of molecular beam by an optical encoding technique.
The relationship between our molecular output scheme and the quantum memory
with three-level atomic ensembles is discussed.
\\ ( http://arXiv.org/abs/quant-ph/0512149 ,  18kb)
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Paper: quant-ph/0512151
Date: Mon, 19 Dec 2005 08:02:12 GMT   (275kb)
Title: Quantum measurements of spatial conjugate variables: Displacement and
tilt of a Gaussian beam
Authors: Vincent Delaubert (LKB - Jussieu, ACQAO), Nicolas Treps (LKB -
Jussieu), Charles C. Harb (ACQAO), Ping Koy Lam (ACQAO), Hans A. Bachor
(ACQAO)
Proxy: ccsd ccsd-00016078
\\
We consider the problem of measurement of optical transverse profile
parameters and their conjugate variable. Using multi-mode analysis, we
introduce the concept of detection noise-modes. For Gaussian beams,
displacement and tilt are a pair of transverse profile conjugate variables. We
experimentally demonstrate their optimal encoding and detection with a spatial
homodyning scheme. Using higher order spatial mode squeezing, we show the
sub-shot noise measurements for the displacement and tilt of a Gaussian beam.
\\ ( http://arXiv.org/abs/quant-ph/0512151 ,  275kb)
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Paper: physics/0512159
Date: Sat, 17 Dec 2005 00:01:15 GMT   (131kb)
Title: A nonadiabatic semi-classical method for dynamics of atoms in optical
lattices
Authors: S. Jonsell, C. M. Dion, M. Nyl\'en, S. J. H. Petra, P. Sj\"olund, A.
Kastberg
Comments: 7 pages, 5 figures, submitted to European Physical Journal D
Subj-class: Atomic Physics
\\
We develop a semi-classical method to simulate the motion of atoms in a
dissipative optical lattice. Our method treats the internal states of the atom
quantum mechanically, including all nonadiabatic couplings, while position and
momentum are treated as classical variables. We test our method in the
one-dimensional case. Excellent agreement with fully quantum mechanical
simulations is found. Our results are much more accurate than those of earlier
semi-classical methods based on the adiabatic approximation.
\\ ( http://arXiv.org/abs/physics/0512159 ,  131kb)
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Paper: cond-mat/0512486
Date: Tue, 20 Dec 2005 06:09:19 GMT   (23kb)
Title: Collective dispersion relations for the 1D interacting two-component
Bose and Fermi gases
Authors: M.T. Batchelor, M. Bortz, X.W. Guan and N. Oelkers
Subj-class: Statistical Mechanics; Strongly Correlated Electrons
\\
We investigate the elementary excitations of charge and spin degrees for the
1D interacting two-component Bose and Fermi gases by means of the discrete
Bethe ansatz equations. Analytic results in the limiting cases of strong and
weak interactions are derived, where the Bosons are treated in the repulsive
and the fermions in the strongly attractive regime. We confirm and complement
results obtained previously from the Bethe ansatz equations in the
thermodynamic limit.
\\ ( http://arXiv.org/abs/cond-mat/0512486 ,  23kb)
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Paper: cond-mat/0512503
Date: Tue, 20 Dec 2005 14:23:17 GMT   (31kb)
Title: Exact diagonalization results for an anharmonically trapped
Bose-Einstein condensate
Authors: S. Bargi, G. M. Kavoulakis, S. M. Reimann (LTH, Lund)
Comments: 7 pages, RevTex, 10 figures
Subj-class: Other
\\
We consider bosonic atoms that rotate in an anharmonic trapping potential.
Using numerical diagonalization of the Hamiltonian, we identify the various
phases of the gas as the rotational frequency of the trap and the coupling
between the atoms are varied.
\\ ( http://arXiv.org/abs/cond-mat/0512503 ,  31kb)
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Paper: cond-mat/0512517
Date: Tue, 20 Dec 2005 19:02:56 GMT   (127kb)
Title: Dynamical mean-field equations for strongly interacting fermionic atoms
in a potential trap
Authors: W. Yi and L.-M. Duan
Subj-class: Other
\\
We derive a set of dynamical mean-field equations for strongly interacting
fermionic atoms in a potential trap across a Feshbach resonance. Our derivation
is based on a variational ansatz, which generalizes the crossover wavefunction
to the inhomogeneous case, and the assumption that the order parameter is
slowly varying over the size of the Cooper pairs. The equations reduce to a
generalized time-dependent Gross-Pitaevskii equation on the BEC side of the
resonance. We discuss an iterative method to solve these mean-field equations,
and present the solution for a harmonic trap as an illustrating example to
self-consistently verify the approximations made in our derivation.
\\ ( http://arXiv.org/abs/cond-mat/0512517 ,  127kb)
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Paper: cond-mat/0512518
Date: Tue, 20 Dec 2005 20:54:55 GMT   (678kb)
Title: Rapid sympathetic cooling to Fermi degeneracy on a chip
Authors: S. Aubin, S. Myrskog, M.H.T. Extavour, L.J. LeBlanc, D. McKay, A.
Stummer, J.H. Thywissen
Subj-class: Statistical Mechanics
\\
Quantum degenerate gases of neutral fermions present new opportunities for
testing many-body condensed matter systems, realizing precision atom
interferometry, producing ultra-cold molecules, and investigating fundamental
forces. Since their first observation [1], degenerate Fermi gases (DFGs) have
continued to be challenging to produce, and have been realized in only a
handful of laboratories [2-10]. In this Letter we report the production of a
DFG achieved using a simple apparatus based on a microfabricated
electromagnetic ($\mu$EM) trap. Similar approaches applied to Bose-Einstein
Condensation (BEC) of $^87$Rb [11,12] have accelerated evaporative cooling and
eliminated the need for multiple vacuum chambers. We demonstrate sympathetic
cooling for the first time in a $\mu$EM trap, and cool $^40^K to Fermi degeneracy in just six seconds -- five to ten times faster than has been possible in conventional magnetic traps. To understand our sympathetic cooling trajectory, we measure the temperature dependence of the$^40$K-$^87$Rb cross-section and observe its Ramsauer-Townsend reduction. \\ ( http://arXiv.org/abs/cond-mat/0512518 , 678kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0510315 replaced with revised version Tue, 20 Dec 2005 15:15:45 GMT (14kb) Title: Superfluidity in a gas of strongly-interacting bosons Authors: G. M. Kavoulakis, Y. Yu, M. Ogren and S. M. Reimann (LTH, Lund) Comments: 4 pages, RevTex, 3 figures, revised version Subj-class: Other \\ ( http://arXiv.org/abs/cond-mat/0510315 , 14kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0511341 replaced with revised version Tue, 20 Dec 2005 18:18:03 GMT (20kb) Title: Surface-atom force out of thermal equilibrium and its effect on ultra-cold atoms Authors: Mauro Antezza Comments: Submitted to JPA Special Issue QFEXT'05 Subj-class: Statistical Mechanics; Soft Condensed Matter; Atomic Physics \\ ( http://arXiv.org/abs/cond-mat/0511341 , 20kb) ------------------------------------------------------------------------------ \\ Paper: quant-ph/0202045 replaced with revised version Tue, 20 Dec 2005 11:13:08 GMT (63kb) Title: Two-Time Correlation Functions: Stochastic and Conventional Quantum Mechanics Authors: L. Feligioni, O. Panella, Y. N. Srivastava and A. Widom Comments: Version published by the Eur. Phys. J. B. Few references added. Minor typos corrected Journal-ref: Eur. Phys. J. B 48, 233-242 (2005) DOI: 10.1140/epjb/e2005-00399-4 \\ ( http://arXiv.org/abs/quant-ph/0202045 , 63kb) ------------------------------------------------------------------------------ \\ Paper: physics/0512184 Date: Tue, 20 Dec 2005 12:38:01 GMT (219kb) Title: Coupled atomic-molecular condensates in a double-well potential: decaying molecular oscillations Authors: Hui Jing, Sihong Gu and Mingsheng Zhan Comments: 6 pages, 4 figures, submitted Subj-class: Atomic Physics \\ We present a four-mode model that describes coherent photo-association (PA) in a double-well Bose-Einstein condensate, focusing on the$average$molecular populations in certain parameters. Our numerical results predict an interesting strong-damping effect of molecular oscillations by controlling the particle tunnellings and PA light strength, which may provide a promising way for creating a stable molecular condensate via coherent PA in a magnetic double-well potential. \\ ( http://arXiv.org/abs/physics/0512184 , 219kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512435 Date: Mon, 19 Dec 2005 08:39:41 GMT (399kb) Title: Unidirectional light emission from high-Q modes in optical microcavities due to resonance-enhanced dynamical tunneling Authors: Jan Wiersig, Martina Hentschel Comments: 4 pages, 6 figures (in reduced resolution) Subj-class: Other; Optics; Chaotic Dynamics \\ We introduce a new scheme to design optical microcavities supporting high-Q modes with unidirectional light emission. This is achieved by coupling a low-Q mode with unidirectional emission to a high-Q mode without directed emission. The coupling is due to enhanced dynamical tunneling near an avoided resonance crossing. Numerical results for a microdisk with a suitably positioned air hole demonstrate the feasibility and the potential of this concept. \\ ( http://arXiv.org/abs/cond-mat/0512435 , 399kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512520 Date: Wed, 21 Dec 2005 20:14:57 GMT (821kb) Title: Sensing electric and magnetic fields with Bose-Einstein Condensates Authors: S. Wildermuth, S. Hofferberth, I. Lesanovsky, S. Groth, I. Bar-Joseph, P. Krueger, and J. Schmiedmayer Comments: 4 pages, 3 figures Subj-class: Other \\ We discuss the application of Bose-Einstein condensates (BECs) as sensors for magnetic and electric fields. In an experimental demonstration we have brought one-dimensional BECs close to micro-fabricated wires on an atom chip and thereby reached a sensitivity to potential variations of ~10e-14eV at 3 micron spatial resolution. We demonstrate the versatility of this sensor by measuring a two-dimensional magnetic field map 10 micron above a 100-micron-wide wire. We show how the transverse current-density component inside the wire can be reconstructed from such maps. The field sensitivity in dependence on the spatial resolution is discussed and further improvements utilizing Feshbach resonances are outlined. \\ ( http://arXiv.org/abs/cond-mat/0512520 , 821kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512537 Date: Wed, 21 Dec 2005 13:14:13 GMT (45kb) Title: Dynamical Aspects of Analogue Gravity: The Backreaction of Quantum Fluctuations in Dilute Bose-Einstein Condensates Authors: Uwe R. Fischer Comments: 23 pages; submitted to Springer Lecture Notes in Physics Subj-class: Other \\ We discuss the backreaction force exerted by quantum fluctuations in dilute Bose-Einstein condensates onto the motion of the classical background, derived by an ab initio approach from microscopic physics. It is shown that the effective-action method, widely employed in semiclassical quantum gravity, fails to give the full backreaction force. The failure of the effective-action method is traced back, inter alia, to the problem of the correct choice of the fundamental variables and the related operator ordering issues. \\ ( http://arXiv.org/abs/cond-mat/0512537 , 45kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512539 Date: Wed, 21 Dec 2005 13:46:21 GMT (12kb) Title: Bragg scattering and the spin structure factor of two-component atomic gases Authors: Iacopo Carusotto Subj-class: Statistical Mechanics; Mesoscopic Systems and Quantum Hall Effect \\ Bragg scattering with linearly polarized light can be used to separately measure the density and the spin structure factor of a two spin component atomic gas by looking at the dependance of the scattering intensity on the polarization of the laser fields. Both stimulated and spontaneous scattering are discussed. Explicit results for different spin configurations are given. \\ ( http://arXiv.org/abs/cond-mat/0512539 , 12kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512548 Date: Wed, 21 Dec 2005 16:07:43 GMT (9kb) Title: Boson dominance in finite and infinite fermion systems Authors: Fabrizio Palumbo Comments: 5 pages, no figure Subj-class: Superconductivity \\ I develop a bosonization method which respects fermion number conservation and is valid for arbitrary fermion-fermion interactions. It reproduces exactly the results of the pairing model of atomic nuclei and of the BCS model of superconductivity in the number conserving form of the quasi-chemical equilibrium theory. \\ ( http://arXiv.org/abs/cond-mat/0512548 , 9kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512550 Date: Wed, 21 Dec 2005 16:37:46 GMT (43kb) Title: Cold atom realizations of Brownian motors Authors: F. Renzoni Subj-class: Other; Statistical Mechanics Journal-ref: Contemp. Phys. 46, 161 (2005) \\ Brownian motors are devices which "rectify" Brownian motion, i.e. they can generate a current of particles out of unbiased fluctuations. Brownian motors are important for the understanding of molecular motors, and are also promising for the realization of new nanolelectronic devices. Among the different systems that can be used to study Brownian motors, cold atoms in optical lattices are quite an unusual one: there is no thermal bath and both the potential and the fluctuations are determined by laser fields. In this article recent experimental implementations of Brownian motors using cold atoms in optical lattices are reviewed. \\ ( http://arXiv.org/abs/cond-mat/0512550 , 43kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512551 Date: Wed, 21 Dec 2005 17:01:06 GMT (21kb) Title: Rectifying fluctuations in an optical lattice Authors: P.H. Jones, M. Goonasekera and F. Renzoni Subj-class: Statistical Mechanics; Other Journal-ref: Phys. Rev. Lett. 93, 073904 (2004) \\ We have realized a Brownian motor by using cold atoms in a dissipative optical lattice as a model system. In our experiment the optical potential is spatially symmetric and the time-symmetry of the system is broken by applying appropriate zero-mean ac forces. We identify a regime of rectification of forces and a regime of rectification of fluctuations, the latter corresponding to the realization of a Brownian motor. \\ ( http://arXiv.org/abs/cond-mat/0512551 , 21kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512552 Date: Wed, 21 Dec 2005 17:10:50 GMT (15kb) Title: Resonant activation in a nonadiabatically driven optical lattice Authors: R. Gommers, P. Douglas, S. Bergamini, M. Goonasekera, P.H. Jones and F. Renzoni Subj-class: Statistical Mechanics; Other Journal-ref: Phys. Rev. Lett. 94, 143001 (2005) \\ We demonstrate the phenomenon of resonant activation in a non-adiabatically driven dissipative optical lattice with broken time-symmetry. The resonant activation results in a resonance as function of the driving frequency in the current of atoms through the periodic potential. We demonstrate that the resonance is produced by the interplay between deterministic driving and fluctuations, and we also show that by changing the frequency of the driving it is possible to control the direction of the diffusion. \\ ( http://arXiv.org/abs/cond-mat/0512552 , 15kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512553 Date: Wed, 21 Dec 2005 17:43:19 GMT (14kb) Title: Dissipation-induced symmetry breaking in a driven optical lattice Authors: R. Gommers, S. Bergamini and F. Renzoni Subj-class: Statistical Mechanics; Other Journal-ref: Phys. Rev. Lett. 95, 073003 (2005) \\ We analyze the atomic dynamics in an ac driven periodic optical potential which is symmetric in both time and space. We experimentally demonstrate that in the presence of dissipation the symmetry is broken, and a current of atoms through the optical lattice is generated as a result. \\ ( http://arXiv.org/abs/cond-mat/0512553 , 14kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512556 Date: Wed, 21 Dec 2005 19:05:39 GMT (20kb) Title: Strongly interacting Fermi gases with density imbalance Authors: J. Kinnunen, L. M. Jensen, and P. Torma Comments: 4 pages, 5 figures Subj-class: Strongly Correlated Electrons; Other; Superconductivity \\ We consider density-imbalanced Fermi gases of atoms in the strongly interacting, i.e. unitarity, regime. The Bogoliubov-deGennes equations for a trapped superfluid are solved. They take into account the finite size of the system, as well as give rise to both phase separation and FFLO type oscillations in the order parameter. We show how radio-frequency spectroscopy reflects the phase separation, and can provide direct evidence of the FFLO-type oscillations via observing the nodes of the order parameter. \\ ( http://arXiv.org/abs/cond-mat/0512556 , 20kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0512584 Date: Thu, 22 Dec 2005 16:10:21 GMT (14kb) Title: Collective excitations of trapped Fermi or Bose gases Authors: A. Csordas, Z. Adam Comments: 4 pages, 3 figures Subj-class: Other \\ A new method is developed to calculate all excitations of trapped gases using hydrodynamics at zero temperature for any equation of state$\mu=\mu(n)\$ and
for any trapping potential. It is shown that a natural scalar product can be
defined for the mode functions, by which the wave operator is hermitian and the
mode functions are orthogonal. It is also shown that the Kohn-modes are exact
for harmonic trapping in hydrodynamic theory. Excitations for fermions are
calculated in the BCS-BEC transition region using the equation of state of the
mean-field Leggett-model for isotrop harmonic trap potential.
\\ ( http://arXiv.org/abs/cond-mat/0512584 ,  14kb)
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Paper: cond-mat/0505055
replaced with revised version Thu, 22 Dec 2005 14:02:53 GMT   (520kb)
Title: Ultracold Superstrings in atomic boson-fermion mixtures
Authors: Michiel Snoek, Masudul Haque, S. Vandoren and H.T.C. Stoof
Comments: 4 pages, 4 figures; published version
Subj-class: Other
DOI: 10.1103/PhysRevLett.95.250401
\\ ( http://arXiv.org/abs/cond-mat/0505055 ,  520kb)
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Paper: cond-mat/0505275
replaced with revised version Thu, 22 Dec 2005 13:06:07 GMT   (185kb)
Title: Quasi two-dimensional superfluid Fermi gases
Authors: J.-P. Martikainen and Paivi Torma
version
Subj-class: Superconductivity
Journal-ref: Phys. Rev. Lett. 95, 170407 (2005)
\\ ( http://arXiv.org/abs/cond-mat/0505275 ,  185kb)
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\\ Paper: cond-mat/0512522
replaced with revised version Thu, 22 Dec 2005 11:51:29 GMT   (340kb)
Title: Correlation and entanglement of two-component Bose-Einstein condensates
in a double well
Authors: Weibin Li, Wenxing Yang, Xiaotao Xie, Jiahua Li, Xiaoxue Yang
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0512522 ,  340kb)
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Paper: cond-mat/0512556
replaced with revised version Thu, 22 Dec 2005 10:06:38 GMT   (20kb)
Title: Strongly interacting Fermi gases with density imbalance
Authors: J. Kinnunen, L. M. Jensen, and P. Torma
Subj-class: Strongly Correlated Electrons; Other; Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0512556 ,  20kb)
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Paper: quant-ph/0512200
Date: Thu, 22 Dec 2005 15:53:03 GMT   (510kb)
Title: Classical capacity of noiseless quantum channels for massive
indistinguishable particles: Bosons vs. fermions
Authors: Aditi Sen De, Ujjwal Sen, Bartosz Gromek, Dagmar Bruss, Maciej
Lewenstein
Comments: 12 pages, 8 eps figures, RevTeX4
\\
The study of channel capacities is directly related to quantum communication
schemes. We consider here classical information transmission through a quantum
channel, where the classical information is encoded into massive
indistinguishable particles: bosons and fermions. We study the situation when
the particles are noninteracting. In the case of noninteracting bosons,
signatures of Bose-Einstein condensation can be observed in the behavior of the
capacity. We show analytically that fermions generally provide higher channel
capacity, i.e., they are better suited for transferring classical information,
in comparison to bosons. This holds for a large range of power law potentials,
and for moderate to high temperatures. Numerical simulations seem to indicate
that the result holds for all temperatures.
\\ ( http://arXiv.org/abs/quant-ph/0512200 ,  510kb)
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Paper: quant-ph/0508143
replaced with revised version Wed, 21 Dec 2005 21:57:07 GMT   (166kb)
Title: Direct Observation of Sub-Poissonian Number Statistics in a Degenerate
Bose Gas
Authors: C.-S. Chuu, F. Schreck, T. P. Meyrath, J. L. Hanssen, G. N. Price, M.
G. Raizen