Matt's arXiv selection, Monday 25th September 2006.

From: Matthew Davis <>
Date: Mon, 25 Sep 2006 10:47:29 +1000 (EST)

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

This week is the mid-semester break... so things are back on schedule!

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The abstracts:

Paper: cond-mat/0609417
Date: Mon, 18 Sep 2006 10:05:43 GMT (454kb)

Title: Quantum depletion of collapsing Bose-Einstein condensates
Authors: S. Wuester, B. J. Dabrowska-Wuester, A. S. Bradley, M. J. Davis, P. B.
   Blakie, J. J. Hope and C. M. Savage
Comments: 8 pages, 4 figures
Subj-class: Other
   We perform the first numerical three-dimensional studies of quantum field
effects in the Bosenova experiment on collapsing condensates by E. Donley et
al. [Nature 415, 39 (2002)] using the exact experimental geometry. In a
stochastic truncated Wigner simulation of the collapse, the collapse times are
larger than the experimentally measured values. We find that a finite
temperature initial state leads to an increased creation of uncondensed atoms,
but not to a reduction of the collapse time. A comparison of the time-dependent
Hartree-Fock-Bogoliubov and Wigner methods for the more tractable spherical
trap shows excellent agreement between the uncondensed populations. We conclude
that the discrepancy between the experimental and theoretical values of the
collapse time cannot be explained by quantum fluctuations or finite temperature
\\ ( , 454kb)
Paper: cond-mat/0603299
replaced with revised version Mon, 18 Sep 2006 15:08:10 GMT (27kb)

Title: Fermions in optical lattices near a Feshbach resonance: from band
   insulator to Mott insulator
Authors: A. F. Ho
Comments: 4 pages, 2 .eps files. Version essentially as published
Subj-class: Mesoscopic Systems and Quantum Hall Effect; Strongly Correlated
\\ ( , 27kb)
Paper: cond-mat/0603489
replaced with revised version Sun, 17 Sep 2006 19:41:18 GMT (16kb)

Title: Comment on "Pairing and Phase Separation in a Polarized Fermi Gas" by G.
   B. Partridge, W. Li, R. I. Kamar, Y. Liao, R. G. Hulet, Science 311, 503
Authors: Martin W. Zwierlein and Wolfgang Ketterle
Comments: Science, in press
Subj-class: Superconductivity; Strongly Correlated Electrons
\\ ( , 16kb)
Paper: cond-mat/0606155
replaced with revised version Mon, 18 Sep 2006 18:18:25 GMT (408kb)

Title: Coherent matter waves emerging from Mott-insulators
Authors: K. Rodriguez, S.R. Manmana, M. Rigol, R.M. Noack and A. Muramatsu
Comments: 20 pages, 11 figures. Published version
Subj-class: Other
Journal-ref: New J. Phys. 8, 169 (2006)
DOI: 10.1088/1367-2630/8/8/169
\\ ( , 408kb)
Paper: cond-mat/0609338
replaced with revised version Sun, 17 Sep 2006 09:24:49 GMT (324kb)

Title: Continuous measurements enhanced self-trapping of degenerate ultra-cold
   atoms: Nonlinear Quantum Zeno Effect
Authors: WeiDong Li and Jie Liu
Comments: 7 pages, 8 figures
Subj-class: Mesoscopic Systems and Quantum Hall Effect; Other
\\ ( , 324kb)
Paper: cond-mat/0609340
replaced with revised version Sun, 17 Sep 2006 09:13:40 GMT (114kb)

Title: The stationary solutions of G-P equations in double square well
Authors: Weidong Li
Comments: 7 pages, 4 figures. accepted by Phys. Rev. A. (2006)
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\ ( , 114kb)
Paper: quant-ph/0609119
Date: Fri, 15 Sep 2006 22:19:50 GMT (76kb)

Title: Ultracold bosons and entanglement in the tilted double-well
Authors: D. R. Dounas-Frazer, A. M. Hermundstad, and L. D. Carr
Comments: 4 pages, 4 figures
   Ultracold bosons in a two-well potential are investigated via a four-mode
model. It is shown that, for typical experimental parameters, the lowest lying
entangled eigenstates cannot be described by the usual two-mode model that
allows particles to occupy only the lowest level in each well. A small
potential difference between the wells, or tilt, will cause the decoherence of
entangled eigenstates. However, entangled states reappear when the tilt is
equal to an integer multiple of twice the interaction strength.
\\ ( , 76kb)
Paper: quant-ph/0609131
Date: Mon, 18 Sep 2006 11:06:03 GMT (106kb)

Title: Converting the entanglement between modes of massive particles into
   Bell-testable forms
Authors: S. Ashhab, Koji Maruyama, Franco Nori
Comments: 7 pages (two-column), 2 figures
   We consider the question of whether it is possible to convert the
entanglement between spatially separated modes of massive particles into a form
that would allow the experimental observation of nonlocal quantum correlations.
In the simplest setups analogous to optics experiments, that conversion is
prohibited by fundamental conservation laws. However, we show that using
auxiliary particles, that goal can be achieved with varying levels of success,
depending on the nature and number of auxiliary particles used. In particular,
we find that an auxiliary Bose-Einstein condensate allows the conversion
arbitrarily many times with a small error that depends only on the initial
state of the condensate.
\\ ( , 106kb)
Paper: quant-ph/0609133
Date: Mon, 18 Sep 2006 14:29:50 GMT (112kb)

Title: Spontaneous emergence of angular momentum Josephson oscillations in
   coupled annular Bose-Einstein condensates
Authors: Igor Lesanovsky and Wolf von Klitzing
   We investigate the nonlinear dynamics of two coupled annular Bose-Einstein
condensates (BECs). For certain values of the coupling strength the nonrotating
ground state is unstable with respect to fluctuations in the higher angular
momentum modes. The two branched Bogoliubov spectrum exhibits distinct regions
of instability enabling one to selectively occupy certain angular momentum
modes. For sufficiently long evolution times angular momentum Josephson
oscillations spontaneously appear, breaking the initial chiral symmetry of the
\\ ( , 112kb)
Paper: quant-ph/0609134
Date: Mon, 18 Sep 2006 16:35:55 GMT (248kb)

Title: Ultrafast Quantum State Control of a Single Trapped Neutral Atom
Authors: Matthew P. A. Jones (LCFIO), Jerome Beugnon (LCFIO), Alpha Ga\"{e}tan
   (LCFIO), Junxiang Zhang (LCFIO), Gaetan Messin (LCFIO), Antoine Browaeys
   (LCFIO), Philippe Grangier (LCFIO)
Proxy: ccsd ccsd-00096007
   We demonstrate the initialisation, read-out and high-speed manipulation of a
qubit stored in a single 87 Rb atom trapped in a submicron-size optical
tweezer. Single qubit rotations are performed on a sub-100 ns time scale using
two-photon Raman transitions. Using the ``spin-echo'' technique, we measure an
irreversible dephasing time of 34 ms. The read-out of the single atom qubit is
at the quantum projection noise limit when averaging up to 1000 individual
\\ ( , 248kb)
Paper: quant-ph/0607175
replaced with revised version Sun, 17 Sep 2006 17:54:01 GMT (42kb)

Title: Universal quantum computation in deocoherence-free subspace with neutral
Authors: P. Xue, and Y.F. Xiao
Comments: 4 pages,2 figures. Final version as published in PRL
\\ ( , 42kb)
Paper: physics/0609145
Date: Sat, 16 Sep 2006 13:56:53 GMT (70kb)

Title: Optical Feshbach resonances of Alkaline-Earth atoms in a 1D or 2D
   optical lattice
Authors: Pascal Naidon and Paul S. Julienne
Comments: 12 pages, 4 figures
Subj-class: Atomic Physics
   Motivated by a recent experiment by Zelevinsky et al. [Phys. Rev. Lett. 96,
203201], we present the theory for photoassociation and optical Feshbach
resonances of atoms confined in a tight one-dimensional (1D) or two-dimensional
(2D) optical lattice. In the case of an alkaline-earth intercombination
resonance, the narrow natural width of the line makes it possible to observe
clear manifestations of the dimensionality, as well as some sensitivity to the
scattering length of the atoms. Among possible applications, a 2D lattice may
be used to increase the spectroscopic resolution by about one order of
magnitude. Furthermore, a 1D lattice induces a shift which provides a new way
of determining the strength of a resonance by spectroscopic measurements.
\\ ( , 70kb)
Paper: physics/0609154
Date: Mon, 18 Sep 2006 18:33:49 GMT (120kb)

Title: Physics in Films: An Assessment
Authors: C. Efthimiou, R. Llewellyn, D. Maronde, T. Winningham
Subj-class: Physics Education
   Physics in Films is an alternative version of the physical science course
offered to non-science majors at the University of Central Florida. The course
uses the popularity of Hollywood films to generate interest in science and to
engage students that have traditionally been resistant to taking science
courses. Scenes that lead to teachable science moments are identified in films
and then used in class to concretize abstract physical concepts. With the wide
variety of movies available, different "flavors" of the course, each
specializing in a certain genre of film, have been created. This creates an
audience of students with a high level of interest in the teaching tool and
helps enhance their learning experience. In addition to the films, the course
uses electronic student response systems to increase class participation.
Although the course was first developed during the academic year 2002-2003, we
continue to develop and assess it. After a brief outline of the motivation for
the development of the course, we will discuss the different versions of the
course and the teaching techniques used, including the use of the student
response systems, and present data on the performance of the students in the
course. Moreover, we will present feedback on the course acquired from video
interviews with participating students.
\\ ( , 120kb)
Paper: cond-mat/0609445
Date: Tue, 19 Sep 2006 05:02:46 GMT (48kb)

Title: Superfluid density and condensate fraction in the BCS-BEC crossover
   regime at finite temperatures
Authors: N. Fukushima, Y. Ohashi, E. Taylor, and A. Griffin
Comments: 32 pages, 12 figures
Subj-class: Materials Science
   The superfluid density is a fundamental quantity describing the response to a
rotation as well as in two-fluid collisional hydrodynamics. We present
extensive calculations of the superfluid density \rho_s in the BCS-BEC
crossover regime of a uniform superfluid Fermi gas at finite temperatures. We
include strong-coupling or fluctuation effects on these quantities within a
Gaussian approximation. We also incorporate the same fluctuation effects into
the BCS single-particle excitations described by the superfluid order parameter
\Delta and Fermi chemical potential \mu, using the Nozi\`eres and Schmitt-Rink
(NSR) approximation. This treatment is shown to be necessary for consistent
treatment of \rho_s over the entire BCS-BEC crossover. We also calculate the
condensate fraction N_c as a function of the temperature, a quantity which is
quite different from the superfluid density \rho_s. We show that the mean-field
expression for the condensate fraction N_c is a good approximation even in the
strong-coupling BEC regime. Our numerical results show how \rho_s and N_c
depend on temperature, from the weak-coupling BCS region to the BEC region of
tightly-bound Cooper pair molecules. In a companion paper by the authors
(cond-mat/0609187), we derive an equivalent expression for \rho_s from the
thermodynamic potential, which exhibits the role of the pairing fluctuations in
a more explicit manner.
\\ ( , 48kb)
Paper: cond-mat/0609468
Date: Tue, 19 Sep 2006 14:54:45 GMT (196kb)

Title: Solitons in a trapped spin-1 atomic condensate
Authors: Wenxian Zhang,\"O. E. M\"ustecapl{\i}o\u{g}lu, and L. You
Comments: 8 pages, 8 eps figures
Subj-class: Other
   We numerically investigate a particular type of spin solitons inside a
trapped atomic spin-1 Bose-Einstein condensate (BEC) with ferromagnetic
interactions. Within the mean field theory approximation, our study of the
solitonic dynamics shows that the solitonic wave function, its center of mass
motion, and the local spin evolutions are stable and are intimately related to
the domain structures studied recently in spin-1 $^{87}$Rb condensates. We
discuss a rotating reference frame wherein the dynamics of the solitonic local
spatial spin distribution become time independent.
\\ ( , 196kb)
Paper: cond-mat/0609472
Date: Tue, 19 Sep 2006 15:32:49 GMT (571kb)

Title: Quantum Hall-like effect for cold atoms in non-Abelian gauge fields
Authors: N. Goldman and P. Gaspard
Comments: 4 pages, 2 figures
Subj-class: Mesoscopic Systems and Quantum Hall Effect
   We show the quantization of the Hall-like transverse conductivity of
fermionic cold atoms in the presence of a non-Abelian gauge field. This
quantization is obtained by relating the transverse conductivity to topological
invariants defined in the non-Abelian framework. The different integer values
of this conductivity are explicitly computed for a specific non-Abelian system
which leads to a fractal phase diagram.
\\ ( , 571kb)
Paper: cond-mat/0609474
Date: Tue, 19 Sep 2006 17:01:06 GMT (13kb)

Title: Dipolar effect in coherent spin mixing of two atoms in a single optical
   lattice site
Authors: B. Sun, W. X. Zhang, S. Yi, M. S. Chapman, L. You
Comments: 4 pages, 3 color eps figures, to appear in Phys. Rev. Lett
Subj-class: Other
   We show that atomic dipolar effects are detectable in the system that
recently demonstrated two-atom coherent spin dynamics within individual lattice
sites of a Mott state. Based on a two-state approximation for the two-atom
internal states and relying on a variational approach, we have estimated the
spin dipolar effect. Despite the absolute weakness of the dipole-dipole
interaction, it is shown that it leads to experimentally observable effects in
the spin mixing dynamics.
\\ ( , 13kb)
Paper: cond-mat/0512517
replaced with revised version Tue, 19 Sep 2006 00:53:47 GMT (127kb)

Title: Dynamical mean-field equations for strongly interacting fermionic atoms
   in a potential trap
Authors: W. Yi and L.-M. Duan
Comments: replaced with the published version
Subj-class: Other
Journal-ref: Europhys. Lett. 75(6), 854 (2006)
DOI: 10.1209/epl/i2006-10210-x
\\ ( , 127kb)
Paper: cond-mat/0601416
replaced with revised version Mon, 18 Sep 2006 21:31:47 GMT (11kb)

Title: Unconventional strongly interacting Bose-Einstein condensates in optical
Authors: A. B. Kuklov
Comments: Replaced with revised version. References are added
Subj-class: Other
Journal-ref: PRL 97, 110405 (2006)
\\ ( , 11kb)
Paper: cond-mat/0605440
replaced with revised version Mon, 18 Sep 2006 20:04:15 GMT (441kb)

Title: Detecting the breached pair phase in a polarized ultracold Fermi gas
Authors: W. Yi and L.-M. Duan
Comments: 4 pages, 3 figures, replaced with the published version
Subj-class: Other
Journal-ref: Phys. Rev. Lett. 97, 120401 (2006)
DOI: 10.1103/PhysRevLett.97.120401
\\ ( , 441kb)
Paper: cond-mat/0606470
replaced with revised version Tue, 19 Sep 2006 19:00:11 GMT (46kb)

Title: BCS-BEC crossover on the two-dimensional honeycomb lattice
Authors: Erhai Zhao, Arun Paramekanti (University of Toronto)
Comments: Significantly revised - added sections on the Fermi surface
   evolution, corrected error in superfluid density, added possible implications
   for high Tc cuprates (nodal metal, quantum criticality)
Subj-class: Superconductivity; Strongly Correlated Electrons
\\ ( , 46kb)
Paper (*cross-listing*): math.DS/0405112
replaced with revised version Mon, 18 Sep 2006 21:47:02 GMT (543kb)

Title: Quasiperiodic Dynamics in Bose-Einstein Condensates in Periodic Lattices
   and Superlattices
Authors: Martijn van Noort, Mason A. Porter, Yingfei Yi, and Shui-Nee Chow
Comments: 29 pages, 6 figures (several with multiple parts; higher-quality
   versions of some of them available at, to appear very soon in Journal of
   Nonlinear Science
Subj-class: Dynamical Systems; Chaotic Dynamics; Soft Condensed Matter; Atomic
MSC-class: MSC: 37J40, 70H99, 37N20; PACS: 05.45.-a, 03.75.Lm, 05.30.Jp,
   05.45.Ac, 03.75.Nt
\\ ( , 543kb)
Paper (*cross-listing*): nlin.PS/0507025
replaced with revised version Mon, 18 Sep 2006 22:19:03 GMT (179kb)

Title: Feshbach Resonance Management of Bose-Einstein Condensates in Optical
Authors: Mason A. Porter, Marina Chugunova, and Dmitry E. Pelinovsky
Comments: 8 pages, 4 figures (1 with six parts, 3 with two parts)
Subj-class: Pattern Formation and Solitons; Other; Atomic Physics; Dynamical
\\ ( , 179kb)
Paper: quant-ph/0609139
Date: Mon, 18 Sep 2006 23:28:46 GMT (83kb)

Title: Gravitationally Induced Decoherence of Optical Entanglement
Authors: T. C. Ralph, G. J. Milburn, T. Downes
   We propose an experiment in which an entangled pair of optical pulses are
propagated through non-uniform gravitational fields. A field operator
calculation of this situation predicts decoherence of the optical entanglement
under experimentally realistic conditions.
\\ ( , 83kb)
Paper: cond-mat/0609484
Date: Tue, 19 Sep 2006 20:12:47 GMT (233kb)

Title: Lowest Landau-level description of a Bose-Einstein condensate in a
   rapidly rotating anisotropic trap
Authors: Alexander L. Fetter
Comments: 13 pages, 1 figure
Subj-class: Statistical Mechanics
   A rapidly rotating Bose-Einstein condensate in a symmetric two-dimensional
trap can be described with the lowest Landau-level set of states. In this case,
the condensate wave function psi(x,y) is a Gaussian function of r^2 = x^2 +
y^2, multiplied by an analytic function P(z) of the single complex variable z=
x+ i y; the zeros of P(z) denote the positions of the vortices. Here, a similar
description is used for a rapidly rotating anisotropic two-dimensional trap
with arbitrary anisotropy (omega_x/omega_y le 1). The corresponding condensate
wave function psi(x,y) has the form of a complex anisotropic Gaussian with a
phase proportional to xy, multiplied by an analytic function P(zeta), where
zeta is proportional to x + i beta_- y and 0 le beta_- le 1 is a real parameter
that depends on the trap anisotropy and the rotation frequency. The zeros of
P(zeta) again fix the locations of the vortices. Within the set of lowest
Landau-level states at zero temperature, an anisotropic parabolic density
profile provides an absolute minimum for the energy, with the vortex density
decreasing slowly and anisotropically away from the trap center.
\\ ( , 233kb)
Paper: cond-mat/0510436
replaced with revised version Wed, 20 Sep 2006 15:29:40 GMT (76kb)

Title: The groundstate of an interacting Bose gas in a harmonic trap -- a
   simple renormalization method
Authors: Roman Werpachowski and Jerzy Kijowski
Comments: RevTex 4, 7 figures
Subj-class: Statistical Mechanics
\\ ( , 76kb)
Paper: cond-mat/0605085
replaced with revised version Wed, 20 Sep 2006 13:54:02 GMT (38kb)

Title: Anomalous specific heat jump in a two-component ultracold Fermi gas
Authors: Armen Sedrakian, Herbert M\"uther, Artur Polls
Comments: 4 pages, 3 figures. v2 includes a discussion of instabilities; v3:
   final version to appear in PRL
Subj-class: Superconductivity; Statistical Mechanics
\\ ( , 38kb)
Paper: cond-mat/0607334
replaced with revised version Wed, 20 Sep 2006 13:52:24 GMT (63kb)

Title: Bragg Spectroscopy of Cold Atomic Fermi Gases
Authors: G. M. Bruun, Gordon Baym
Comments: 8 pages, 9 figures. Typos corrected. Reference updated
Subj-class: Superconductivity
\\ ( , 63kb)
Paper: quant-ph/0609150
Date: Tue, 19 Sep 2006 20:17:30 GMT (360kb)

Title: Influence of a tight isotropic harmonic trap on photoassociation in
   ultracold homonuclear alkali gases
Authors: Sergey Grishkevich and Alejandro Saenz
Comments: 19 pages, 17 figures
   The influence of a tight isotropic harmonic trap on photoassociation of two
ultracold alkali atoms forming a homonuclear diatomic is investigated using
realistic atomic interaction potentials. Confinement of the initial atom pair
due to the trap leads to a uniform strong enhancement of the photoassociation
rate to most, but also to a strongly suppressed rate for some final states.
Thus tighter traps do not necessarily enhance the photoassociation rate. A
further massive enhancement of the rate is found for strong interatomic
interaction potentials. The details of this interaction play a minor role,
except for large repulsive interactions for which a sharp window occurs in the
photoassociation spectrum as is known from the trap-free case. A comparison
with simplified models describing the atomic interaction like the
pseudopotential approximation shows that they often provide reasonable
estimates for the trap-induced enhancement of the photoassociation rate even if
the predicted rates can be completely erroneous.
\\ ( , 360kb)
Paper: physics/0609166
Date: Wed, 20 Sep 2006 09:18:59 GMT (164kb)

Title: Experimental study of laser detected magnetic resonance based on atomic
Authors: Gianni Di Domenico, Georg Bison, Stephan Groeger, Paul Knowles,
   Anatoly S. Pazgalev, Martin Rebetez, Herve Saudan, Antoine Weis
Comments: 8 pages, 9 figures. Submitted to Phys. Rev. A. Related to
Subj-class: Atomic Physics
   We present an experimental study of the spectra produced by
optical/radio-frequency double resonance in which resonant linearly polarized
laser light is used in the optical pumping and detection processes. We show
that the experimental spectra obtained for cesium are in excellent agreement
with a very general theoretical model developed in our group and we investigate
the limitations of this model. Finally, the results are discussed in view of
their use in the study of relaxation processes in aligned alkali vapors.
\\ ( , 164kb)

Paper: cond-mat/0609529
Date: Wed, 20 Sep 2006 21:59:26 GMT (307kb)

Title: Bose-Einstein Condensation and Kinetic energy of liquid $^3$He-$^4$He
Authors: S.O. Diallo, J.V. Pearce, R.T. Azuah, F. Albergamo and H.R. Glyde
Subj-class: Statistical Mechanics; Superconductivity
   We present neutron scattering measurements of the momentum distribution of
liquid ${^3}$He-${^4}$He mixtures. The experiments were performed at
wavevectors $Q$, 26 $\leq$ $Q$ $\leq$ 29 {\AA$^{-1}$}, on the MARI
time-of-flight spectrometer at the ISIS Facility, Rutherford Appleton
Laboratory, a spallation neutron source. Mixtures with $^3$He concentrations
$x$ between 0 and 20% were investigated both in the superfluid and normal
phases. From the data, we extract the Bose-Einstein condensate fraction $n_0$
and the momentum distributions of $^3$He and $^4$He atoms. We find that $n_0$
increases somewhat above the pure $^4$He value when $^3$He is added; e.g from
$n_0=(7.25\pm0.75)%$ at $x=$ 0 to $(11\pm3)%$ at $x=$ 15-20%. This agrees with
predictions but is less than the only previous measurement. We find a $^4$He
kinetic energy $K_4$ for pure $^4$He that agrees with previous determinations.
$K_4$ decreases somewhat with increasing $^3$He concentration, less than
observed previously and found in early calculations but in agreement with a
more recent Monte Carlo calculation. The $^3$He response is not well reproduced
by a Fermi gas momentum distribution, $n(\bf{k})$. Rather an $n(\bf{k})$ having
a small step height at the Fermi surface and a substantial high momentum tail
characteristic of a strongly interacting Fermi liquid provides a good fit. This
$n(\bf{k})$ is consistent with calculated $n(\bf{k})$. Thus agreement between
theory and experiment is obtained comparing $n(\bf{k})$ in contrast to earlier
findings based on comparing calculated and observed $^3$He kinetic energies.
\\ ( , 307kb)
Paper: cond-mat/0609531
Date: Wed, 20 Sep 2006 22:15:23 GMT (18kb)

Title: Detecting multi-atomic composite states in optical lattices
Authors: Anatoly Kuklov and Henning Moritz
Comments: 9 revtex pages
Subj-class: Other
   We propose and discuss methods for detecting quasi-molecular complexes which
are expected to form in strongly interacting optical lattice systems.
Particular emphasis is placed on the detection of composite fermions forming in
Bose-Fermi mixtures. We argue that, as an indirect indication of the composite
fermions and a generic consequence of strong interactions, periodic
correlations must appear in the atom shot noise of bosonic absorption images,
similar to the bosonic Mott insulator [S. F\"olling, et al., Nature {\bf 434},
481 (2005)]. The composites can also be detected directly and their
quasi-momentum distribution measured. This method -- an extension of the
technique of noise correlation interferometry [E. Altman et al., Phys. Rev. A
{\bf 79}, 013603 (2004)] -- relies on measuring higher order correlations
between the bosonic and fermionic shot noise in the absorption images. However,
it fails for complexes consisting of more than three atoms.
\\ ( , 18kb)
Paper: cond-mat/0609535
Date: Thu, 21 Sep 2006 06:35:46 GMT (81kb)

Title: Many-body quantum ratchet in a Bose-Einstein condensate
Authors: Dario Poletti, Giuliano Benenti, Giulio Casati and Baowen Li
Comments: 4 pages, 4 figures
Subj-class: Other
   We study the dynamics of a dilute Bose-Einstein condensate confined in a
toroidal trap and exposed to a pair of periodically flashed optical lattices.
We first prove that in the noninteracting case this system can present a
quantum symmetry which forbids the ratchet effect classically expected. We then
show how many-body atom-atom interactions, treated within the mean-field
approximation, can break this quantum symmetry, thus generating directed
\\ ( , 81kb)
Paper: cond-mat/0609553
Date: Thu, 21 Sep 2006 17:53:31 GMT (9kb)

Title: On 1+1 Dimensional Galilean Supersymmetry in Ultracold Quantum Gases
Authors: G.S.Lozano, O.Piguet, F.A.Schaposnik, L. Sourrouille
Comments: 12 pages
Subj-class: Other
   We discuss a 1+1 dimensional Galilean invariant model recently introduced in
connection with ultracold quantum gases. After showing its relation to a
nonrelativistic 2+1 Chern-Simons matter system, we identify the generators of
the supersymmetry and its relation with the existence of self-dual equations
\\ ( , 9kb)
Paper: quant-ph/0609163
Date: Thu, 21 Sep 2006 15:01:43 GMT (49kb)

Title: Quantum mechanics: Myths and facts
Authors: H. Nikolic
Comments: 28 two-column pages, pedagogic review
   A common understanding of quantum mechanics (QM) among students and practical
users is often plagued by a number of "myths", that is, widely accepted claims
on which there is not really a general consensus among experts in foundations
of QM. These myths include wave-particle duality, time-energy uncertainty
relation, fundamental randomness, the absence of measurement-independent
reality, locality of QM, nonlocality of QM, the existence of well-defined
relativistic QM, the claims that quantum field theory (QFT) solves the problems
of relativistic QM or that QFT is a theory of particles, as well as myths on
black-hole entropy. The fact is that the existence of various theoretical and
interpretational ambiguities underlying these myths does not yet allow us to
accept them as proven facts. I review the main arguments and counterarguments
lying behind these myths and conclude that QM is still a
not-yet-completely-understood theory open to further fundamental research.
\\ ( , 49kb)
Paper: physics/0609176
Date: Thu, 21 Sep 2006 02:06:35 GMT (29kb)

Title: Precise Numerical Solutions of Potential Problems Using Crank-Nicholson
Authors: Daekyoung Kang and E. Won
Comments: 10 pages, 1 figure. Submitted to Phys. Rev. Lett
Subj-class: Computational Physics; Atomic Physics
   A new numerical treatment in the Crank-Nicholson method with the imaginary
time evolution operator is presented in order to solve the Schr\"{o}dinger
equation. The original time evolution technique is extended to a new operator
that provides a systematic way to calculate not only eigenvalues of ground
state but also of excited states. This new method systematically produces
eigenvalues with accuracies of eleven digits with the Cornell potential that
covers non-perturbative regime. An absolute error estimation technique based on
a power counting rule is implemented. This method is examined with exactly
solvable problems and produces the numerical accuracy down to 10$^{-11}$.
\\ ( , 29kb)

Till next week,

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
Legal stuff: Unless stated otherwise, this e-mail represents only the
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Received on Mon Sep 25 2006 - 10:47:29 EST

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