Matt's arXiv selection: week ending 26 September 2008.

From: Matthew Davis <>
Date: Thu, 09 Oct 2008 17:17:10 +1000

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

Hi all,

For the first time in a long while, I'm now less than a week behind... 28 new
preprints and 21 replacements this week.

Date: Thu, 18 Sep 2008 20:00:10 GMT (29kb)

Title: Discerning Incompressible and Compressible Phases of Cold Atoms in
   Optical Lattices
Authors: V.W. Scarola, L. Pollet, J. Oitmaa, M. Troyer
Categories: cond-mat.other
   Experiments with cold atoms trapped in optical lattices offer the potential
to realize a variety of novel phases but suffer from severe spatial
inhomogeneity that can obscure signatures of new phases of matter and phase
boundaries. We use a high temperature series expansion to show that
compressibility in the core of a trapped Fermi-Hubbard system is related to
measurements of changes in double occupancy. This {\em core compressibility}
filters out edge effects, offering a direct probe of compressibility
independent of inhomogeneity. A comparison with experiments is made.
\\ ( , 29kb)
Date: Fri, 19 Sep 2008 17:30:08 GMT (175kb)

Title: Superfluid and Fermi liquid phases of Bose-Fermi mixtures in optical
Authors: Kaushik Mitra, C. J. Williams and C. A. R. S\'a de Melo
Categories: cond-mat.other
Comments: 4 pages, 2 figures
   We describe interacting mixtures of ultracold bosonic and fermionic atoms in
harmonically confined optical lattices. For a suitable choice of parameters we
study the emergence of superfluid and Fermi liquid (non-insulating) regions out
of Bose-Mott and Fermi-band insulators, due to finite Boson and Fermion
hopping. We obtain the shell structure for the system and show that angular
momentum can be transferred to the non-insulating regions from
Laguerre-Gaussian beams, which combined with Bragg spectroscopy can reveal all
superfluid and Fermi liquid shells.
\\ ( , 175kb)
Date: Fri, 19 Sep 2008 06:43:27 GMT (42kb,D)

Title: Heisenberg-limited phase estimation without entanglement or adaptive
Authors: B. L. Higgins, D. W. Berry, S. D. Bartlett, M. W. Mitchell, H. M.
   Wiseman and G. J. Pryde
Categories: quant-ph
Comments: 5 pages, 2 figures
   We derive, and experimentally demonstrate, a scheme for Heisenberg-limited
phase estimation that requires neither adaptive measurements nor multiphoton
entangled states. Like a recently introduced adaptive technique [Higgins et
al., Nature 450, 393 (2007)], it employs single photons and multiple
applications of the phase shift. By not requiring adaptive measurements, but
rather using a predetermined measurement sequence, the present scheme is both
conceptually simpler and significantly easier to implement. Additionally, we
demonstrate a simplified adaptive scheme that also surpasses the standard
quantum limit.
\\ ( , 42kb)

Date: Sat, 20 Sep 2008 19:35:13 GMT (266kb)

Title: Unitary perturbation theory approach to real-time evolution problems
Authors: A. Hackl, S. Kehrein
Categories: cond-mat.str-el
Comments: 23 pages, 6 pages
   We discuss a new analytical approach to real-time evolution in quantum
many-body systems. Our approach extends the framework of continuous unitary
transformations such that it amounts to a novel solution method for the
Heisenberg equations of motion for an operator. It is our purpose to illustrate
the accuracy of this approach by studying dissipative quantum systems on all
time scales. In particular, we obtain results for non-equilibrium correlation
functions for general initial conditions. We illustrate our ideas for the
exactly solvable dissipative oscillator, and, as a non-trivial model, for the
dissipative two-state system.
\\ ( , 266kb)
Date: Mon, 22 Sep 2008 06:33:13 GMT (61kb)

Title: Damping in 2D and 3D dilute Bose gases
Authors: Ming-Chiang Chung and Aranya B. Bhattacherjee
Categories: cond-mat.other
Comments: 11 pages, 4 figures
   Damping in 2D and 3D dilute gases is investigated using both the
hydrodynamical approach and the Hartree-Fock-Bogoliubov (HFB) approximation .
We found that the both methods are good for the Beliaev damping at zero
temperature and Landau damping at very low temperature, however, at high
temperature, the hydrodynamical approach overestimates the Landau damping and
the HFB gives a better approximation. This result shows that the comparison of
the theoretical calculation using the hydrodynamical approach and the
experimental data for high temperature done by Vincent Liu (PRL {\bf21} 4056
(1997)) is not proper. For two-dimensional systems, we show that the Beliaev
damping rate is proportional to $k^3$ and the Landau damping rate is
proportional to $ T^2$ for low temperature and to $T$ for high temperature. We
also show that the hydrodynamical approach gives the same result for zero
temperature and low temperature as HFB, but overestimates the Landau damping
for high temperature.
\\ ( , 61kb)
Date: Mon, 22 Sep 2008 11:00:09 GMT (680kb,D)

Title: Dissipation induced Tonks-Girardeau gas in an optical lattice
Authors: J. J. Garcia-Ripoll, S. D\"urr, N. Syassen, D. M. Bauer, M. Lettner,
   G. Rempe, J. I. Cirac
Categories: cond-mat.other
   We present a theoretical investigation of a lattice Tonks-gas that is created
by inelastic, instead of elastic interactions. An analytical calculation shows
that in the limit of strong two-body losses, the dynamics of the system is
effectively that of a Tonks gas. We also derive an analytic expression for the
effective loss rate. We find good agreement between these analytical results
and results from a rigorous numerical calculation. The Tonks character of the
gas is visible both in a reduced effective loss rate and in the momentum
distribution of the gas.
\\ ( , 680kb)
Date: Mon, 22 Sep 2008 11:09:27 GMT (16kb)

Title: Many-body approach to low-lying collective excitations in a BEC
   approaching collapse
Authors: Anindya Biswas and Tapan Kumar Das
Categories: cond-mat.other
Comments: 8 pages, 2 figures
   An approximate many-body theory incorporating two-body correlations has been
employed to calculate low-lying collective multipole frequencies in a
Bose-Einstein condensate containing $A$ bosons, for different values of the
interaction parameter $\lambda=\frac{Aa_{s}}{a_{ho}}$. Significant difference
from the variational estimate of the Gross-Pitaevskii equation has been found
near the collapse region. This is attributed to two-body correlations and
finite range attraction of the realistic interatomic interaction.
\\ ( , 16kb)
Date: Mon, 22 Sep 2008 12:29:35 GMT (60kb)

Title: Lieb-Liniger Model of a Dissipation-Induced Tonks-Girardeau Gas
Authors: S. D\"urr, J. J. Garcia-Ripoll, N. Syassen, D. M. Bauer, M. Lettner,
   J. I. Cirac, G. Rempe
Categories: cond-mat.other
   We show that strong inelastic interactions between bosons in one dimension
create a Tonks-Girardeau gas, much like in the case of elastic interactions. We
derive a Markovian master equation that describes the loss caused by the
inelastic collisions. This yields a loss rate equation and a dissipative
Lieb-Liniger model. We obtain an analytic expression for the pair correlation
function in the limit of strong dissipation. Numerical calculations show how a
diverging dissipation strength leads to a vanishing of the actual loss rate and
renders an additional elastic part of the interaction irrelevant.
\\ ( , 60kb)
Date: Mon, 22 Sep 2008 16:34:26 GMT (80kb)

Title: Any order imaginary time propagation method for solving the Schrodinger
Authors: Siu A. Chin, S. Janecek and E. Krotscheck
Categories: cond-mat.mtrl-sci cond-mat.str-el
Comments: 8 pages, 3 figures
   The eigenvalue-function pair of the 3D Schr\"odinger equation can be
efficiently computed by use of high order, imaginary time propagators. Due to
the diffusion character of the kinetic energy operator in imaginary time,
algorithms developed so far are at most fourth-order. In this work, we show
that for a grid based algorithm, imaginary time propagation of any even order
can be devised on the basis of multi-product splitting. The effectiveness of
these algorithms, up to the 12$^{\rm th}$ order, is demonstrated by computing
all 120 eigenstates of a model C$_{60}$ molecule to very high precisions. The
algorithms are particularly useful when implemented on parallel computer
\\ ( , 80kb)
Date: Sat, 20 Sep 2008 16:12:43 GMT (293kb)

Title: Aspects of quantum phase transitions
Authors: M. K. G. Kruse, H. G. Millerr, A. Plastino, A. R. Plastino
Categories: quant-ph cond-mat.stat-mech
   A unified description of i) classical phase transitions and their remnants in
finite systems and ii) quantum phase transitions is here presented. The ensuing
discussion relies on the interplay between, on the one hand, the thermodynamic
concepts of temperature and specific heat and on the other, the quantal ones of
coupling strengths in the Hamiltonian. Our considerations are illustrated by
recourse to an exactly solvable model of Plastino and Moszkowski [Il Nuovo
Cimento {\bf 47}, 470 (1978)].
\\ ( , 293kb)
Date: Mon, 22 Sep 2008 19:39:06 GMT (289kb)

Title: Efimov Trimer Formation via Ultracold Four-body Recombination
Authors: Yujun Wang (Department of Physics, Kansas State University) and B. D.
   Esry (Department of Physics, Kansas State University)
Categories: quant-ph
Comments: 5 pages, 3 figures
   We discuss the collisional formation of Efimov trimers via ultracold
four-body recombination. In particular, we consider the reaction A+A+A+B->A3+B
with A and B ultracold atoms. We obtain expressions for the four-body
recombination rate and show that it reflects the three-body Efimov physics
either as a function of collision energy or as a function of the two-body
s-wave scattering length between A atoms. In addition, we briefly discuss
issues important for experimentally observing this interesting and relatively
unexplored process.
\\ ( , 289kb)
Date: Tue, 23 Sep 2008 02:52:16 GMT (379kb)

Title: Directional spatial structure of dissociated elongated molecular
Authors: Magnus \"Ogren, C.M. Savage, K.V. Kheruntsyan
Categories: cond-mat.other
   Ultra-cold clouds of dimeric molecules can dissociate into quantum
mechanically correlated constituent atoms that are either bosons or fermions.
We theoretically model the dissociation of cigar shaped molecular condensates,
for which this difference manifests as complementary geometric structures of
the dissociated atoms. For atomic bosons beams form along the long axis of the
molecular condensate. For atomic fermions beams form along the short axis. This
directional beaming simplifies the measurement of correlations between the
atoms through relative number squeezing.
\\ ( , 379kb)
Date: Tue, 23 Sep 2008 14:01:07 GMT (2729kb)

Title: Ultracold Feshbach Molecules
Authors: Francesca Ferlaino, Steven Knoop, and Rudolf Grimm
Categories: cond-mat.other cond-mat.stat-mech
Comments: Chapter of the book: "Cold molecules: Creation and applications",
   edited by R. V. Krems, B. Friedrich and W. C. Stwalley, and published by
   Taylor & Francis (March 2009)
   In this Chapter, we give an introduction into experiments with Feshbach
molecules and their applications. In particular, we discuss the various
creation and detection methods, and the internal-state manipulation of such
molecules. We highlight two topics, namely Feshbach molecules in the halo
regime and the application of Feshbach molecule to achieve ultracold gases of
molecules in the rovibrational ground state. Our illustrative examples are
mainly based on work performed at Innsbruck University.
\\ ( , 2729kb)
Date: Tue, 23 Sep 2008 17:44:58 GMT (67kb)

Title: Van-der-Waals potentials of paramagnetic atoms
Authors: Hassan Safari, Dirk-Gunnar Welsch, Stefan Yoshi Buhmann, Stefan Scheel
Categories: quant-ph
Comments: 18 pages, 3 figures, 1 table
   We study single- and two-atom van der Waals interactions of ground-state
atoms which are both polarizable and paramagnetizable in the presence of
magneto-electric bodies within the framework of macroscopic quantum
electrodynamics. Starting from an interaction Hamiltonian that includes
particle spins, we use leading-order perturbation theory for the van der Waals
potentials expressed in terms of the polarizability and magnetizability of the
atom(s). To allow for atoms embedded in media, we also include local-field
corrections via the real-cavity model. The general theory is applied to the
potential of a single atom near a half space and that of two atoms embedded in
a bulk medium or placed near a sphere, respectively.
\\ ( , 67kb)
Date: Wed, 24 Sep 2008 07:38:32 GMT (53kb)

Title: Spatially-modulated Superfluid States in Fermionic Optical Ladder
   Systems with Repulsive Interactions
Authors: Yusuke Fujihara, Akihisa Koga, Norio Kawakami
Categories: cond-mat.stat-mech cond-mat.supr-con
Comments: 8 pages, 5 figures
   We investigate two-component ultracold fermionic atoms with repulsive
interactions trapped in an optical lattice with a ladder structure. By applying
the Bogoliubov-de Gennes equations to an effective t-J model in the strong
correlation limit, we discuss how the spatially-modulated spin-singlet pairs
with d-wave like symmetry are formed in the systems with trapping potentials.
Furthermore, a close examination of the condensation energy as well as the
local average of potential, kinetic and exchange energies by means of the
variational Monte Carlo method elucidates that local particle correlations
enhance the stability of the superfluid state via substantial energy gain due
to singlet pairing in the high particle density region.
\\ ( , 53kb)
Date: Wed, 24 Sep 2008 13:51:38 GMT (20kb)

Title: BEC-BCS crossover in a Bose gas
Authors: Arnaud Koetsier, P. Massignan, R. A. Duine and H. T. C. Stoof
Categories: cond-mat.other
Comments: 4 pages, 3 figures, RevTeX
Report-no: ITP-UU-08/56
   We calculate the critical temperature for pair condensation in a gas of
bosonic atoms across a Feshbach resonance. Using the Nozieres-Schmitt-Rink
formalism, we show how medium effects at negative scattering lengths give rise
to pairs which are reminiscent of the ones responsible for fermionic
superfluidity. Furthermore, we find that these preformed pairs lead to a strong
suppression of the critical temperature for superfluidity. We also find that
the compressibility of the gas in its normal phase is positive, and therefore
confirm its mechanical stability throughout the entire crossover region.
Finally, we discuss prospects of observing this crossover in a gas of ultracold
133Cs atoms where recent measurements indicate that this bosonic gas may be
sufficiently long-lived to explore the crossover experimentally.
\\ ( , 20kb)
Date: Wed, 24 Sep 2008 16:25:15 GMT (670kb)

Title: Bragg spectroscopy and Ramsey interferometry with an ultracold Fermi gas
Authors: B. Deh, C. Marzok, S. Slama, C. Zimmermann, and Ph. W. Courteille
Categories: cond-mat.other
Comments: 19 pages, 10 figures
   We report on the observation of Bragg scattering of an ultracold Fermi gas of
6Li atoms at a dynamic optical potential. The momentum states produced in this
way oscillate in the trap for time scales on the order of seconds, nearly
unperturbed by collisions, which are absent for ultracold fermions due to the
Pauli principle. In contrast, interactions in a mixture with 87Rb atoms lead to
rapid damping. The coherence of these states is demonstrated by Ramsey-type
matter wave interferometry. The signal is improved using an echo pulse
sequence, allowing us to observe coherence times longer than 100 mus. Finally
we use Bragg spectroscopy to measure the in-situ momentum distribution of the
6Li cloud. Signatures for the degeneracy of the Fermi gas can be observed
directly from the momentum distribution of the atoms inside the trap.
\\ ( , 670kb)

Date: Wed, 24 Sep 2008 22:47:09 GMT (545kb,D)

Title: Collapse times of dipolar Bose-Einstein condensates
Authors: C. Ticknor, N.G. Parker, A. Melatos, S.L. Cornish, D.H.J. O'Dell and
   A.M Martin
Categories: cond-mat.other
Comments: 5 pages with 3 figures
   We investigate the time taken for global collapse by a dipolar Bose-Einstein
condensate. Two semi-analytical approaches and exact numerical integration of
the mean-field dynamics are considered. The semi-analytical approaches are
based on a Gaussian ansatz and a Thomas-Fermi solution for the shape of the
condensate. The regimes of validity for these two approaches are determined,
and their predictions for the collapse time revealed and compared with
numerical simulations. The dipolar interactions introduce anisotropy into the
collapse dynamics and predominantly lead to collapse in the plane perpendicular
to the axis of polarization.
\\ ( , 545kb)

Date: Thu, 25 Sep 2008 01:48:42 GMT (69kb)

Title: Non-Abelian Josephson effect between two spinor Bose-Einstein
   condensates in double optical traps
Authors: Ran Qi, Xiao-Lu Yu, Z. B. Li and W. M. Liu
Categories: cond-mat.other
Comments: 5 pages, 3 figures
   We investigate the non-Abelian Josephson effect in spinor Bose-Einstein
condensates with double optical traps. We propose, for the first time, a real
physical system which contains non-Abelian Josephson effects. The collective
modes of this weak coupling system have very different density and spin
tunneling characters comparing to the Abelian case. We calculate the
frequencies of the pseudo Goldstone modes in different phases between two traps
respectively, which are a crucial feature of the non-Abelian Josephson effects.
We also give an experimental protocol to observe this novel effect in future
\\ ( , 69kb)

Date: Thu, 25 Sep 2008 10:00:47 GMT (912kb)

Title: Vortex solitons in dipolar Bose-Einstein Condensates
Authors: I. Tikhonenkov, B. A. Malomed, A. Vardi
Categories: cond-mat.other
Comments: 6 pages, 6 figures
   We predict solitary vortices in quasi-planar condensates of dipolar atoms,
polarized parallel to the confinement direction, with the effective sign of the
dipole-dipole interaction inverted by means of a rapidly rotating field. Energy
minima corresponding to vortex solitons with topological charges ${% \ell}=1$
and 2 are predicted for moderately strong dipole-dipole interaction, using an
axisymmetric Gaussian ansatz. The stability of the solitons with $\ell =1$ is
confirmed by full 3D simulations, whereas their counterparts with $\ell =2$ are
found to be unstable against splitting into a set of four fragments
\\ ( , 912kb)

Date: Thu, 25 Sep 2008 13:29:44 GMT (1646kb,D)

Title: Recent progress in open quantum systems: Non-Gaussian noise and
   decoherence in fermionic systems
Authors: Clemens Neuenhahn, B. Kubala, B. Abel, Florian Marquardt
Categories: cond-mat.mes-hall
Comments: Proceedings of Ustron 2008 conference, 6 pages, 3 figures
   We review our recent contributions to two topics that have become of interest
in the field of open, dissipative quantum systems: non-Gaussian noise and
decoherence in fermionic systems. Decoherence by non-Gaussian noise, i.e. by an
environment that cannot be approximated as a bath of harmonic oscillators, is
important in nanostructures (e.g. qubits) where there might be strong coupling
to a small number of fluctuators. We first revisit the pedagogical example of
dephasing by classical telegraph noise. Then we address two models where the
quantum nature of the noise becomes essential: "quantum telegraph noise" and
dephasing by electronic shot noise. In fermionic systems, many-body aspects and
the Pauli principle have to be taken care of when describing the loss of phase
coherence. This is relevant in electronic quantum transport through metallic
and semiconducting structures. Specifically, we recount our recent results
regarding dephasing in a chiral interacting electron liquid, as it is realized
in the electronic Mach-Zehnder interferometer. This model can be solved
employing the technique of bosonization as well as a physically transparent
semiclassical method.
\\ ( , 1646kb)

Date: Thu, 25 Sep 2008 13:51:30 GMT (1447kb)

Title: Finite temperature vortex dynamics in Bose Einstein condensates
Authors: B. Jackson, N.P. Proukakis, C.F. Barenghi and E. Zaremba
Categories: cond-mat.stat-mech
Comments: 16 pages, 10 figures, submitted
   We study the decay of vortices in Bose-Einstein condensates at finite
temperatures by means of the Zaremba Nikuni Griffin formalism, in which the
condensate is modelled by a Gross Pitaevskiiequation, which is coupled to a
Boltzmann kinetic equation for the thermal cloud. At finite temperature, an
off-centred vortex in a harmonically trapped pancake shaped condensate decays
by spiralling out towards the edge of the condensate. This decay, which depends
heavily on temperature and atomic collisions, agrees with that predicted by the
Hall Vinen phenomenological model of friction force, which is used to describe
quantised vorticity in superfluid systems. Our result thus clarifies the
microscopic origin of the friction and provides an ab initio determination of
its value.
\\ ( , 1447kb)

Date: Thu, 25 Sep 2008 14:55:03 GMT (456kb)

Title: Fermionization of a strongly interacting Bose-Fermi mixture in a
   one-dimensional harmonic trap
Authors: Bess Yiyuan Fang (University of Singapore), Patrizia Vignolo (INLN,
   Nice, France), Christian Miniatura (INLN, Nice, France), Anna Minguzzi
   (LPMMC, Grenoble, France)
Categories: cond-mat.other
Comments: 8 pages, 7 figures
   We consider a strongly interacting one-dimensional (1D) Bose-Fermi mixture
confined in a harmonic trap. It consists of a Tonks-Girardeau (TG) gas (1D Bose
gas with repulsive hard-core interactions) and of a non-interacting Fermi gas
(1D spin-aligned Fermi gas), both species interacting through hard-core
repulsive interactions. Using a generalized Bose-Fermi mapping, we determine
the exact particle density profiles, momentum distributions and behaviour of
the mixture under 1D expansion when opening the trap. In real space, bosons and
fermions do not display any phase separation: the respective density profiles
extend over the same region and they both present a number of peaks equal to
the total number of particles in the trap. In momentum space the bosonic
component has the typical narrow TG profile, while the fermionic component
shows a broad distribution with fermionic oscillations at small momenta. Due to
the large boson-fermion repulsive interactions, both the bosonic and the
fermionic momentum distributions decay as $C p^{-4}$ at large momenta, like in
the case of a pure bosonic TG gas. The coefficient $C$ is related to the
two-body density matrix and to the bosonic concentration in the mixture. When
opening the trap, both momentum distributions "fermionize" under expansion and
turn into that of a Fermi gas with a particle number equal to the total number
of particles in the mixture.
\\ ( , 456kb)

Date: Thu, 25 Sep 2008 13:14:35 GMT (1468kb)

Title: Quantum computing with trapped ions
Authors: H. Haeffner, C.F. Roos, R. Blatt
Categories: quant-ph
Comments: Review article, accepted for publication in Physics Reports, 99pages,
   38 Figures, ~2 MByte
   Quantum computers hold the promise to solve certain computational task much
more efficiently than classical computers. We review the recent experimental
advancements towards a quantum computer with trapped ions. In particular,
various implementations of qubits, quantum gates and some key experiments are
discussed. Furthermore, we review some implementations of quantum algorithms
such as a deterministic teleportation of quantum information and an error
correction scheme.
\\ ( , 1468kb)

Date: Thu, 25 Sep 2008 10:54:15 GMT (904kb,D)

Title: Quantum resonances in the delta-kicked harmonic oscillator
Authors: T. P. Billam and S. A. Gardiner
Categories: quant-ph
Comments: 4 pages, 3 figures
   We investigate characteristic quantum resonances occurring in the
delta-kicked harmonic oscillator theoretically. We develop a physical
explanation for the quantum resonances based on symmetries shared between the
classical phase space and the quantum-mechanical time evolution operator. We
show that the primary quantum resonances correspond to a situation where action
of the applied kicks is entirely commutative, and that higher order resonances
correspond to a partial commutativity. We suggest experimental conditions in an
atom-optical context under which the primary quantum resonances could be
directly observed.
\\ ( , 904kb)

Date: Thu, 25 Sep 2008 12:27:58 GMT (1064kb)

Title: Freezing a Coherent Field Growth in a Cavity by Quantum Zeno Effect
Authors: Julien Bernu (LKB - Lhomond), Samuel Del\'eglise (LKB - Lhomond),
   Cl\'ement Sayrin (LKB - Lhomond), Stefan Kuhr, Igor Dotsenko (LKB - Lhomond,
   CDF), Michel Brune (LKB - Lhomond), Jean-Michel Raimond (LKB - Lhomond),
   Serge Haroche (LKB - Lhomond)
Categories: quant-ph
   We have frozen the coherent evolution of a field in a cavity by repeated
measurements of its photon number. We use circular Rydberg atoms dispersively
coupled to the cavity mode for an absorption-free photon counting. These
measurements inhibit the growth of a Field injected in the cavity by a
classical source. This manifestation of the Quantum Zeno effect illustrates the
back action of the photon number determination onto the Field phase. The
residual growth of the Field can be seen as a random walk of its amplitude in
the two-dimensional phase space. This experiment sheds light onto the
measurement process and opens perspectives for active quantum feedback.
\\ ( , 1064kb)

Date: Thu, 25 Sep 2008 18:32:50 GMT (16kb)

Title: A term-rewriting system for computer quantum algebra
Authors: J. J. Hudson
Categories: quant-ph
Comments: 16 pages, 1 table
   Existing computer algebra packages do not fully support quantum mechanics
calculations in Dirac's notation. I present the foundation for building such
support: a mathematical system for the symbolic manipulation of expressions
used in the invariant formalism of quantum mechanics. I first describe the
essential mathematical features of the Hilbert-space invariant formalism. This
is followed by a formal characterisation of all possible algebraic expressions
in this formalism. This characterisation is provided in the form of a set of
terms. Rewrite rules over this set of terms are then developed that correspond
to allowed manipulations of the algebraic expressions. This approach is
contrasted with current attempts to build invariant quantum mechanics
calculations into computer algebra systems.
\\ ( , 16kb)

and something I couldn't resist including... who could have possibly thought
this might be a risk????

arXiv:0809.4004 (*cross-listing*)
Date: Tue, 23 Sep 2008 20:00:51 GMT (6kb)

Title: There is no explosion risk associated with superfluid Helium in the LHC
   cooling system
Authors: Malcolm Fairbairn and Bob McElrath
Categories: physics.pop-ph cond-mat.other hep-ex hep-ph physics.atom-ph
Comments: 6 pages
   We evaluate speculation about the possibility of a dangerous release of
energy within the liquid Helium of the Large Hadron Collider (LHC) cryogenic
system due to the occurrence of a "Bose-Nova". Bose-Novae are radial bursts of
rapidly moving atoms which can occur when a Bose-Einstein Condensate (BEC)
undergoes a collapse due the interatomic potential being deliberately made
attractive using a magnetic field close to the Feshbach resonance. Liquid 4He
has a monatomic structure with s-wave electrons, zero nuclear spin, no
hyperfine splitting, and as a consequence no Feshbach resonance which would
allow one to change its normally repulsive interactions to be attractive.
Because of this, a Bose-Nova style collapse of 4He is impossible. Additional
speculations concerning cold fusion during these events are easily dismissed
using the usual arguments about the Coulomb barrier at low temperatures, and
are not needed to explain the Bose-Einstein condensate Bose-Nova phenomenon. We
conclude that that there is no physics whatsoever which suggests that Helium
could undergo any kind of unforeseen catastrophic explosion.
\\ ( , 6kb)

The replacements:

replaced with revised version Fri, 19 Sep 2008 13:21:58 GMT (39kb,D)

Title: Accurate determination of the superfluid-insulator transition in the
   one-dimensional Bose-Hubbard model
Authors: Jakub Zakrzewski and Dominique Delande
Categories: cond-mat.stat-mech cond-mat.other
Comments: revised version, modified fig.1, a reference added, 5pp. 3figs
\\ ( , 39kb)
replaced with revised version Fri, 19 Sep 2008 13:17:46 GMT (113kb)

Title: Splitting of doubly quantized vortices in dilute Bose-Einstein
Authors: K. Gawryluk, T. Karpiuk, M. Brewczyk, K. Rzazewski
Categories: cond-mat.other
Comments: 1 page, 1 figure
Journal-ref: Phys. Rev. A 78, 025603 (2008)
DOI: 10.1103/PhysRevA.78.025603
\\ ( , 113kb)
replaced with revised version Fri, 19 Sep 2008 19:41:57 GMT (377kb)

Title: Thermodynamics of a trapped unitary Fermi gas
Authors: R. Haussmann and W. Zwerger
Categories: cond-mat.stat-mech
Comments: 10 pages, 5 figures
Report-no: KN-08-05
\\ ( , 377kb)
replaced with revised version Fri, 19 Sep 2008 12:12:24 GMT (120kb)

Title: Spectral signatures of the Fulde-Ferrell-Larkin-Ovchinnikov order
   parameter in one-dimensional optical lattices
Authors: M. Reza Bakhtiari, M.J. Leskinen, P. Torma
Categories: cond-mat.other
Comments: published version
Journal-ref: Phys.Rev.Lett. 101, 120404 (2008)
DOI: 10.1103/PhysRevLett.101.120404
\\ ( , 120kb)
replaced with revised version Fri, 19 Sep 2008 18:22:53 GMT (42kb)

Title: Internal structure of a quantum soliton and classical excitations due to
   trap opening
Authors: Yvan Castin (LKB - Lhomond)
Categories: cond-mat.other
Comments: 12 pages; 2 figures added ; a few typos corrected
\\ ( , 42kb)
arXiv:0809.1818 (*cross-listing*)
replaced with revised version Fri, 19 Sep 2008 15:10:46 GMT (26kb)

Title: Transition to the giant vortex state for a Bose-Einstein condensate in a
   rotating anharmonic trap
Authors: Nicolas Rougerie
Categories: math-ph cond-mat.other math.MP
Comments: 40 pages
MSC-class: 35Q55,47J30,76M23
\\ ( , 26kb)
replaced with revised version Fri, 19 Sep 2008 13:21:38 GMT (150kb)

Title: Ultracold Molecules in the Ro-Vibrational Triplet Ground State
Authors: F. Lang, K. Winkler, C. Strauss, R. Grimm, J. Hecker Denschlag
Categories: quant-ph
Comments: 4 pages, 3 figures. Phys. Rev. Lett. accepted
\\ ( , 150kb)
replaced with revised version Fri, 19 Sep 2008 08:06:14 GMT (246kb)

Title: Formation of ultracold polar molecules in the rovibrational ground state
Authors: J. Deiglmayr, A. Grochola, M. Repp, K. M\"ortlbauer, C. Gl\"uck, J.
   Lange, O. Dulieu, R. Wester, and M. Weidem\"uller
Categories: quant-ph physics.atom-ph
\\ ( , 246kb)
replaced with revised version Mon, 22 Sep 2008 05:02:25 GMT (51kb)

Title: Criterion for Bose-Einstein condensation in traps and self-bound systems
Authors: T. Yamada, Y. Funaki, H. Horiuchi, G. Roepke, P. Schuck, and A.
Categories: cond-mat.other nucl-th
Comments: Shortened to Brief report
Journal-ref: Phys. Rev. A 78, 035603 (2008)
\\ ( , 51kb)
replaced with revised version Mon, 22 Sep 2008 08:01:05 GMT (286kb)

Title: Incommensurate superfluidity of bosons in a double-well optical lattice
Authors: Vladimir M. Stojanovic, Congjun Wu, W. Vincent Liu, S. Das Sarma
Categories: cond-mat.other quant-ph
Comments: 4 pages, 5 figures;
Journal-ref: Phys. Rev. Lett. 101, 125301 (2008)
DOI: 10.1103/PhysRevLett.101.125301
\\ ( , 286kb)
replaced with revised version Mon, 22 Sep 2008 16:29:20 GMT (34kb)

Title: Trapping and cooling fermionic atoms into the Mott and N\'eel states
Authors: L. De Leo, C. Kollath, A. Georges, M. Ferrero, O. Parcollet
Categories: cond-mat.str-el
Comments: New version submitted to PRL on September 12. More quantitative
   discussion of D vs. N, in connection with local compressibility
\\ ( , 34kb)
replaced with revised version Mon, 22 Sep 2008 14:21:09 GMT (258kb)

Title: Damped bounces of an isolated perfect quantum gas
Authors: S. Camalet
Categories: cond-mat.mes-hall
\\ ( , 258kb)
replaced with revised version Tue, 23 Sep 2008 05:13:35 GMT (914kb,D)

Title: Physical replicas and the Bose-glass in cold atomic gases
Authors: S. Morrison, A. Kantian, A. J. Daley, H.G. Katzgraber, M. Lewenstein,
   H. P. B\"uchler, and P. Zoller
Categories: cond-mat.other cond-mat.dis-nn
Comments: 17 pages, 6 figures, updated and added several references, other
   minor changes and corrections
Journal-ref: New J. Phys. 10, 073032 (2008)
DOI: 10.1088/1367-2630/10/7/073032
\\ ( , 914kb)
replaced with revised version Tue, 23 Sep 2008 04:38:06 GMT (852kb,D)

Title: Dissipation-driven quantum phase transitions in collective spin systems
Authors: S. Morrison and A. S. Parkins
Categories: quant-ph cond-mat.other
Comments: 12 pages, 16 figures, removed section on homodyne spectra
Journal-ref: J. Phys. B 41, 195502 (2008)
DOI: 10.1088/0953-4075/41/19/195502
\\ ( , 852kb)
replaced with revised version Tue, 23 Sep 2008 16:03:56 GMT (644kb,D)

Title: Fractional resonances in the atom-optical delta-kicked accelerator
Authors: M. Saunders, P.L. Halkyard, S.A. Gardiner, and K.J. Challis
Categories: physics.atom-ph nlin.CD
Comments: 18 pages, 8 figures
\\ ( , 644kb)
replaced with revised version Wed, 24 Sep 2008 06:14:56 GMT (42kb)

Title: Order via Nonlinearity in Randomly Confined Bose Gases
Authors: Robert Graham and Axel Pelster
Categories: cond-mat.dis-nn
Comments: Author Information under International Journal
   of Bifurcation and Chaos (in press)
\\ ( , 42kb)
replaced with revised version Wed, 24 Sep 2008 08:00:25 GMT (67kb)

Title: Interband physics in an ultra-cold Fermi gas in an optical lattice
Authors: J.-P. Martikainen, E. Lundh, and T. Paananen
Categories: cond-mat.stat-mech cond-mat.supr-con
Comments: 5 pages, 2 figures
Report-no: NORDITA-2008-17
Journal-ref: Phys. Rev. A 78, 023607 (2008)
\\ ( , 67kb)
replaced with revised version Wed, 24 Sep 2008 08:02:16 GMT (14kb)

Title: Cooper problem in a lattice
Authors: J.-P. Martikainen
Categories: cond-mat.stat-mech cond-mat.supr-con
Comments: 4 pages, 3 figures
Report-no: NORDITA-2008-32
Journal-ref: Phys. Rev. A 78, 035602 (2008)
\\ ( , 14kb)
replaced with revised version Wed, 24 Sep 2008 08:17:47 GMT (538kb)

Title: Energy distribution and cooling of a single atom in an optical tweezer
Authors: C. Tuchendler, A. M. Lance, A. Browaeys, Y. R. P. Sortais and P.
Categories: quant-ph
Comments: 9 pages, 6 figures, published in PRA
Journal-ref: Phys. Rev. A 78, 033425 (2008)
\\ ( , 538kb)
replaced with revised version Thu, 25 Sep 2008 09:55:50 GMT (564kb,D)

Title: Quantum Non-Demolition Detection of Strongly Correlated Systems
Authors: Kai Eckert, Oriol Romero-Isart, Mirta Rodriguez, Maciej Lewenstein,
   Eugene S. Polzik and Anna Sanpera
Categories: cond-mat.other quant-ph
Comments: Published version
Journal-ref: Nature Physics 4, 50-54 (2008)
DOI: 10.1038/nphys776
\\ ( , 564kb)
replaced with revised version Thu, 25 Sep 2008 07:20:13 GMT (916kb,D)

Title: Paired atom laser beams created via four-wave mixing
Authors: R. G. Dall, L. J. Byron, A. G. Truscott, G. R. Dennis, M. T. Johnsson,
   J. J. Hope
Categories: quant-ph
Comments: 5 pages, 3 figures
\\ ( , 916kb)

Till next time,

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
Matt's arXiv selection: weekly summary of cold-atom papers from
Legal stuff: Unless stated otherwise, this e-mail represents only the
views of the sender and not the views of the University of Queensland
Received on Fri Oct 10 2008 - 13:21:20 EST

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