Matt's arXiv selection: week ending 24 November 2008

From: Matthew Davis <>
Date: Thu, 04 Dec 2008 09:50:01 +1000

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

Dear all,

Things have been a bit busy for me recently - with a very nice workshop on
quantum atom optics in Lorne, Victoria (Australia), and also my wife has had the
flu so I've spent some time at home looking after my kids. I'm off to New
Zealand on the weekend for more conference/collaboration, but I'm hoping I will
be up to date with the arXiv fairly shortly!

It was a busy week - there were 37 new preprints and 19 replacements:

Date: Thu, 13 Nov 2008 21:27:14 GMT (189kb)

Title: Universal state diagrams for harmonically trapped bosons in optical
Authors: Marcos Rigol, George G. Batrouni, Valery G. Rousseau, Richard T.
Categories: cond-mat.other cond-mat.stat-mech
Comments: 10 pages, 10 figures
   We use quantum Monte-Carlo simulations to obtain universal zero temperature
state diagrams for strongly correlated lattice bosons in one and two dimensions
under the influence of a harmonic confining potential. Since harmonic traps
generate a coexistence of superfluid and Mott insulating domains, we use local
quantities like the quantum fluctuations of the density and a local
compressibility to identify the phases present in the inhomogeneous density
profiles. We emphasize the use of the 'characteristic density' to produce a
universal state diagram which is relevant to experimental optical lattice
systems, regardless of the number of bosons or trap curvature. We show that the
critical value of U/t at which Mott insulating domains appear in the trap
depends on the filling in the system, and it is in general greater than the
value in the homogeneous system. Recent experimental results by Spielman et al.
[Phys. Rev. Lett. 100, 120402 (2008)] are analyzed in the context of our
two-dimensional state diagram, and shown to exhibit a value for the critical
point in good agreement with simulations. We also study the effects of finite,
but low T<t/2, temperatures. We find that in two dimensions they have little
influence on our zero temperature results, while their effect is more
pronounced in one dimension.
\\ ( , 189kb)
Date: Fri, 14 Nov 2008 13:11:44 GMT (84kb)

Title: Superfluid to Mott-insulator transition of cold atoms in optical
Authors: N. Dupuis and K. Sengupta
Categories: cond-mat.other
Comments: 6 pages, Proceedings of the 5th International Workshop on Electronic
   Crystals (ECRYS 2008)
   We review the superfluid to Mott-insulator transition of cold atoms in
optical lattices. The experimental signatures of the transition are discussed
and the RPA theory of the Bose-Hubbard model briefly described. We point out
that the critical behavior at the transition, as well as the prediction by the
RPA theory of a gapped mode (besides the Bogoliubov sound mode) in the
superfluid phase, are difficult to understand from the Bogoliubov theory. On
the other hand, these findings appear to be intimately connected to the
non-trivial infrared behavior of the superfluid phase as recently studied
within the non-perturbative renormalization group.
\\ ( , 84kb)
Date: Fri, 14 Nov 2008 16:41:37 GMT (1036kb,D)

Title: Precision molecular spectroscopy for ground state transfer of molecular
   quantum gases
Authors: Johann G. Danzl, Manfred J. Mark, Elmar Haller, Mattias Gustavsson,
   Nadia Bouloufa, Olivier Dulieu, Helmut Ritsch, Russell Hart, and
   Hanns-Christoph Naegerl
Categories: cond-mat.other
Comments: 6 figures, 1 table
   One possibility for the creation of ultracold, high-phase-space-density
quantum gases of molecules in the rovibrational ground state relies on first
associating weakly-bound molecules from quantum-degenerate atomic gases on a
Feshbach resonance and then transfering the molecules via several steps of
coherent two-photon stimulated Raman adiabatic passage (STIRAP) into the
rovibronic ground state. Here, in ultracold samples of Cs_2 Feshbach molecules
produced out of ultracold samples of Cs atoms, we observe several optical
transitions to deeply bound rovibrational levels of the excited 0_u^+ molecular
potentials with high resolution. At least one of these transitions, although
rather weak, allows efficient STIRAP transfer into the deeply bound vibrational
level |v=73> of the singlet X ^1Sigma_g^+ ground state potential, as recently
demonstrated. From this level, the rovibrational ground state level |v=0, J=0>
can be reached with one more transfer step. In total, our results show that
coherent ground state transfer for Cs_2 is possible using a maximum of two
successive two-photon processes or one single four-photon STIRAP process.
\\ ( , 1036kb)
Date: Fri, 14 Nov 2008 11:15:34 GMT (379kb)

Title: Non-Gaussian two-mode squeezing and continuous variable entanglement of
   linearly and circularly polarized light beams interacting with cold atoms
Authors: R. J. Missori, M. C. de Oliveira, and K. Furuya
Categories: quant-ph
Comments: 10 pages, 7 figures
   We investigate how entangled coherent states and superpositions of low
intensity coherent states of non-Gaussian nature can be generated via
non-resonant interaction between either two linearly or circularly polarized
field modes and an ensemble of X-like four-level atoms placed in an optical
cavity. We compare our results to recent experimental observations and argue
that the non-Gaussian structure of the field states may be present in those
\\ ( , 379kb)
Date: Fri, 14 Nov 2008 11:16:27 GMT (566kb)

Title: Slow-light Faraday effect: an atomic probe with gigahertz bandwidth
Authors: Paul Siddons, Nia C Bell, Yifei Cai, Charles S Adams and Ifan G Hughes
Categories: physics.atom-ph
Comments: 13 pages, 6 figures. Submitted to Nature Photonics
   The ability to control the speed and polarisation of light pulses will allow
for faster data flow in optical networks of the future. Optical delay and
switching have been achieved using slow-light techniques in various media,
including atomic vapour. Most of these vapour schemes utilise resonant
narrowband techniques for optical switching, but suffer the drawback of having
a limited frequency range or high loss. In contrast, the Faraday effect in a
Doppler-broadened slow-light medium allows polarisation switching over tens of
GHz with high transmission. This large frequency range opens up the possibility
of switching telecommunication bandwidth pulses and probing of dynamics on a
nanosecond timescale. Here we demonstrate the slow-light Faraday effect for
light detuned far from resonance. We show that the polarisation dependent group
index can split a linearly polarised nanosecond pulse into left and right
circularly polarised components. The group index also enhances the spectral
sensitivity of the polarisation rotation, and large rotations of up to 15 pi
rad are observed for continuous-wave light. Finally, we demonstrate dynamic
broadband pulse switching, by rotating a linearly polarised nanosecond pulse
from vertical to horizontal with no distortion and transmission close to unity.
\\ ( , 566kb)
Date: Fri, 14 Nov 2008 21:05:54 GMT (9kb)

Title: Large-Distance Asymptotic Behavior of the Correlation Functions of 1D
   Impenetrable Anyons at Finite Temperatures
Authors: Ovidiu I. Patu, Vladimir E. Korepin, Dmitri V. Averin
Categories: cond-mat.stat-mech
Comments: 5 pages, RevTeX4
   The large-distance asymptotic behavior of the field-field correlators has
been computed for one-dimensional impenetrable anyons at finite temperatures.
The asymptotic behavior agrees with the predictions of conformal field theory
at low temperatures and reproduces the known results for impenetrable bosons
and free fermions in appropriate limits. We have also obtained an integrable
system of partial nonlinear differential equations which completely
characterizes the 2-point correlation functions. The system is the same as for
bosons but with different initial conditions.
\\ ( , 9kb)
Date: Mon, 17 Nov 2008 12:40:50 GMT (148kb)

Title: Stationary waves in a supersonic flow of a two-component Bose gas
Authors: L.Yu. Kravchenko, D.V. Fil
Categories: cond-mat.other
Comments: 10 pages, 8 figures
   A stationary wave pattern occurring in a flow of a two-component
Bose-Einstein condensate past an obstacle is studied. Stationary waves arise at
the velocities of the components at which the Landau criterion is violated. If
the components flow with the same velocity two sets of stationary waves can
arise. If the velocity of one component is equal to zero only one set of waves
is possible. Two sets of waves also arise if the velocities approximately equal
in values and the angle between the velocities is close to $\pi/2$. Under
increase of the relative velocity of the components the spectrum of the
excitations becomes complex valued and the stationary wave pattern is broken.
We obtain a ratio between excess densities of the components for the stationary
waves. This ratio depends on the superfluid velocities of the components, it is
different for different sets of waves, and can vary along crests of waves.
\\ ( , 148kb)
Date: Mon, 17 Nov 2008 08:20:04 GMT (858kb,D)

Title: PGPE theory of finite temperature collective modes for a trapped Bose
Authors: A. Bezett and P. B. Blakie
Categories: cond-mat.other
Comments: 15 pages, 16 figures
   We develop formalism based on the projected Gross Pitaevskii equation to
simulate the finite temperature collective mode experiments of Jin et al. [PRL
78, 764 (1997)]. We examine the $m=0$ and $m=2$ quadrupolar modes on the
temperature range $0.51T_c-0.83T_c$ and calculate the frequencies of, and phase
between, the condensate and noncondensate modes, and the condensate mode
damping rate. This study is the first quantitative comparison of the projected
Gross-Pitaevskii equation to experimental results in a dynamical regime.
\\ ( , 858kb)
Date: Mon, 17 Nov 2008 11:21:46 GMT (52kb)

Title: Spin dynamics in a one-dimensional Bose-Hubbard model
Authors: M. B. Zvonarev, V. V. Cheianov, T. Giamarchi
Categories: cond-mat.other
Comments: 4 pages, 2 figures
   We investigate the dynamics of a one-dimensional strongly repulsive
ferromagnetic Bose-Hubbard model close to unit filling. We derive the
propagator of transverse spin waves and the corresponding spectral function. We
demonstrate that arbitrarily small hole doping leads to a strong modification
of the long-time dynamics of the spin propagator as compared with the undoped
case. For the spectral function this is seen in the non-trivial structure of
the magnon peak.
\\ ( , 52kb)
Date: Mon, 17 Nov 2008 17:58:14 GMT (45kb)

Title: Effective Nonlinear Schr\"odinger Equations for Cigar-Shaped and
   Disk-Shaped Fermi Superfluids at Unitarity
Authors: S. K. Adhikari and L. Salasnich
Categories: cond-mat.other
Comments: 22 pages, 5 figures
   In the case of tight transverse confinement (cigar-shaped trap) the
three-dimensional (3D) nonlinear Schr\"odinger equation, describing superfluid
Fermi atoms at unitarity (infinite scattering length $|a|\to \infty$), is
reduced to an effective one-dimensional form by averaging over the transverse
coordinates. The resultant effective equation is a 1D nonpolynomial Schrodinger
equation, which produces results in good agreement with the original 3D one. In
the limit of small and large fermion number $N$ the nonlinearity is of simple
power-law type. A similar reduction of the 3D theory to a two-dimensional form
is also performed for a tight axial confinement (disk-shaped trap). The
resultant effective 2D nonpolynomial equation also produces results in
agreement with the original 3D equation and has simple power-law nonlinearity
for small and large $N$. For both cigar- and disk-shaped superfluids our
nonpolynomial Schr\"odinger equations are quite attractive for phenomenological
\\ ( , 45kb)
Date: Sat, 15 Nov 2008 10:47:18 GMT (483kb)

Title: Negative-index media for matter-wave optics
Authors: J. Baudon, M. Hamamda, J. Grucker, F. Perales, G. Dutier, M. Boustimi
   and M. Ducloy
Categories: quant-ph physics.optics
Comments: 4 pages, 4 figures, submitted at PRL 4 November 2008
   We consider the extension of optical meta-materials to matter waves. We show
that the generic property of pulsed comoving magnetic fields allows us to
fashion the wave-number dependence of the atomic phase shift. It can be used to
produce a transient negative group velocity of an atomic wave packet, which
results into a negative refraction of the matter wave. Application to slow
metastable argon atoms Ar*(3P2) shows that the device is able to operate either
as an efficient beam splitter or an atomic meta-lens. Implications of
"meta-media" in atom optics are considered.
\\ ( , 483kb)
Date: Mon, 17 Nov 2008 13:43:44 GMT (324kb)

Title: Coherent shift of localized bound pair in Bose Hubbard model
Authors: L. Jin, B. Chen, and Z. Song
Categories: quant-ph
Comments: 5 pages, 3 figures
   Based on the exact results obtained by Bethe ansatz, we demonstrate the
existence of stable bound pair (BP) wave packet in Bose Hubbard model with
arbitrary on-site interaction U. In large-U regime, it is found that an
incoming single-particle (SP) can coherently pass through a BP wave packet and
leave a coherent shift in the position of it. This suggests a simple scheme for
constructing a BP charge qubit to realize a quantum switch, which is capable of
controlling the coherent transport of one and only one photon in a
one-dimensional waveguide.
\\ ( , 324kb)
Date: Mon, 17 Nov 2008 18:28:14 GMT (83kb,D)

Title: Momentum exchange between light and a single atom: Abraham or Minkowski?
Authors: E. A. Hinds and Stephen M. Barnett
Categories: quant-ph
Comments: 4 pages, 1 figure
   We consider the forces exerted by a pulse of plane-wave light on a single
atom. The leading edge of the pulse exerts a dispersive force on the atom, and
this modifies the atomic momentum while the atom is enveloped in the light. The
standard view of the optical dipole force indicates that red-detuned light
should attract the atom towards high intensity. This should increase the
average momentum per photon to $\textbf{p}_{0} n$, where $\textbf{p}_{0}$ is
the photon momentum in free space and $n$ is the average refractive index due
to the presence of the atom in the light. We show, however, that this is the
wrong conclusion and that the atom is in fact repelled from the light by the
dispersive forces, giving the photons a momentum $\textbf{p}_{0} /n$. This
leads us to identify Abraham's optical momentum with the kinetic momentum
transfer. The form due to Minkowski is similarly associated with the canonical
momentum. We consider the possibility of demonstrating this in the laboratory,
and we note an unexpected connection with the Aharonov-Casher effect.
\\ ( , 83kb)
Date: Sat, 15 Nov 2008 01:44:10 GMT (976kb)

Title: A new method for producing ultracold molecular ions
Authors: Eric R. Hudson
Categories: physics.atom-ph physics.chem-ph quant-ph
   We propose a new method for the production of ultracold molecular ions. This
method utilizes sympathetic cooling due to the strong collisions between
appropriately chosen molecular ions and laser-cooled neutral atoms to realize
ultracold, internal ground-state molecular ions. In contrast to other
experiments producing cold molecular ions, our proposed method efficiently
cools both the internal and external molecular ion degrees of freedom. The
availability of an ultracold, absolute ground-state sample of molecular ions
would have broad impact to fields as diverse as quantum chemistry,
astrophysics, and fundamental physics; and may lead to the development of a
robust, scalable quantum computer.
\\ ( , 976kb)
Date: Mon, 17 Nov 2008 21:01:17 GMT (613kb)

Title: Probing condensate order in deep optical lattices
Authors: Kuei Sun, Courtney Lannert, Smitha Vishveshwara
Categories: cond-mat.other
Comments: 14 pages, 9 figures, RevTeX
   We study interacting bosons in optical lattices in the weak-tunneling regime
where the system in a harmonic trap is inhomogeneous with Mott-insulating and
condensed phases coexisting at zero temperature. We discuss the nature of the
number-fixed condensed ground state in this regime and the validity of the
mean-field treatment thereof. We suggest two experimental signatures of
condensate order in the system. (1) We analyze the hyperfine configuration of
the system, and propose a set of experimental parameters for observing
radio-frequency (RF) spectra which would distinguish the condensed phase from
the Mott insulating phase. We derive the structure of the signal from the
condensate in a typical trapped system, taking into account Goldstone
excitations, and discuss its evolution as a function of temperature. (2) We
study matter-wave interference patterns displayed by the system upon release
from all confining potentials. We show that the density profiles evolve very
differently for the Mott insulating phase and the condensed phase, and can be
distinguished from one another when the two phases co-exist.
\\ ( , 613kb)
Date: Tue, 18 Nov 2008 08:38:22 GMT (17kb)

Title: Universal Critical Velocity for the Onset of Turbulence of Oscillatory
   Superfluid Flow
Authors: R. H\"anninen and W. Schoepe
Categories: cond-mat.other
Comments: 5 pages and 3 figures. Proceedings of the "Low Temperature Quantum
   Phenomena and Devices": Symposium in Espoo, Finland, March 28-30, 2008
Journal-ref: J. Low Temp. Phys. 153, 189-196 (2008)
DOI: 10.1007/s10909-008-9834-2
   The critical velocity vc for the onset of turbulent drag of small spheres
oscillating in superfluid 4He is frequency dependent (omega/2pi from 100 Hz to
700 Hz) and is described by vc = 2.6sqrt(kappa*omega), where kappa is the
circulation quantum. A qualitative analysis based on a recent theory of the
onset of superfluid turbulence gives vc = sqrt(8*kappa*omega/beta), where beta
is of order 1 and depends on the coefficients of mutual friction. This agrees
well with the data and implies that vc is a universal critical velocity that is
independent of geometry, size, and surface properties of the oscillating body.
This is confirmed by comparing our data on spheres with vc obtained with other
oscillating structures by other groups. Numerical simulations indicate somewhat
larger critical velocity, above which a rapid increase in vortex length is
\\ ( , 17kb)
Date: Tue, 18 Nov 2008 08:10:00 GMT (13kb)

Title: Noise induced interference fringes in trapped ultracold bosonic gases
Authors: S. Anderloni, F. Benatti, R. Floreanini, G. G. Guerreschi
Categories: quant-ph
Comments: 14 pages, LaTex
   We study the dynamics of ultracold atoms trapped in optical double-well
potentials in presence of noise generated by an external environment. When
prepared in a Fock number state, the system shows phase coherence in the
averaged density profile obtained using standard absorption image techniques,
that disappears in absence of noise. This effect indicates that also in
many-body systems an external environment may enhance quantum coherence,
instead of destroying it.
\\ ( , 13kb)
Date: Tue, 18 Nov 2008 16:43:36 GMT (2911kb,D)

Title: Prospects for measuring the electric dipole moment of the electron using
   electrically trapped polar molecules
Authors: M. R. Tarbutt, J. J. Hudson, B. E. Sauer, E. A. Hinds
Categories: physics.atom-ph
Comments: 22 pages, 7 figures, prepared for Faraday Discussion 142
   Heavy polar molecules can be used to measure the electric dipole moment of
the electron, which is a sensitive probe of physics beyond the Standard Model.
The value is determined by measuring the precession of the molecule's spin in a
plane perpendicular to an applied electric field. The longer this precession
evolves coherently, the higher the precision of the measurement. For molecules
in a trap, this coherence time could be very long indeed. We evaluate the
sensitivity of an experiment where neutral molecules are trapped electrically,
and compare this to an equivalent measurement in a molecular beam. We consider
the use of a Stark decelerator to load the trap from a supersonic source, and
calculate the deceleration efficiency for YbF molecules in both strong-field
seeking and weak-field seeking states. With a 1s holding time in the trap, the
statistical sensitivity could be ten times higher than it is in the beam
experiment, and this could improve by a further factor of five if the trap can
be loaded from a source of larger emittance. We study some effects due to field
inhomogeneity in the trap and find that rotation of the electric field
direction, leading to an inhomogeneous geometric phase shift, is the primary
obstacle to a sensitive trap-based measurement.
\\ ( , 2911kb)
Date: Tue, 18 Nov 2008 21:54:51 GMT (32kb)

Title: Rotation induced superfluid-normal phase separation in trapped Fermi
Authors: M. Iskin and E. Tiesinga
Categories: cond-mat.supr-con cond-mat.other
Comments: 5 pages with 3 figures
   We use the Bogoliubov-de Gennes formalism to analyze the effects of rotation
on the ground state phases of harmonically trapped Fermi gases, under the
assumption that quantized vortices are not excited. We find that the rotation
breaks Cooper pairs that are located near the trap edge, and that this leads to
a phase separation between the nonrotating superfluid (fully paired) atoms
located around the trap center and the rigidly rotating normal (nonpaired)
atoms located towards the trap edge, with a coexistence (partially paired)
region in between. Furthermore, we show that the rotation reveals a topological
quantum phase transition: the superfluid phase that occurs in the coexistence
region is characterized by a gapless excitation spectrum, and that it is
distinct from the gapped phase that occurs near the trap center.
\\ ( , 32kb)
Date: Wed, 19 Nov 2008 05:57:06 GMT (466kb)

Title: Spontaneous mass current and textures of p-wave superfluids of trapped
   Fermionic atom gases at rest and under rotation
Authors: Y. Tsutsumi, K. Machida
Categories: cond-mat.supr-con
Comments: 5 pages, 5 figures
   It is found theoretically based on the Ginzburg-Landau framework that p-wave
superfluids of neutral atom gases in three dimension harmonic traps exhibit
spontaneous mass current at rest, whose direction depends on trap geometry.
Under rotation various types of the order parameter textures are stabilized,
including Mermin-Ho and Anderson-Toulouse-Chechetkin vortices. In a cigar shape
trap spontaneous current flows longitudial to the rotation axis and thus
perpendicular to the ordinary rotational current. These features, spontaneous
mass current at rest and texture formation, can be used as diagnoses for p-wave
\\ ( , 466kb)
Date: Wed, 19 Nov 2008 10:37:46 GMT (24kb)

Title: Out-of-equilibrium bosons on a one-dimensional optical random lattice
Authors: Thierry Platini (LPM), Rosemary J. Harris, Dragi Karevski (LPM)
Categories: cond-mat.stat-mech
   We study the transport properties of a one-dimensional hard-core boson
lattice gas coupled to two particle reservoirs at different chemical potentials
generating a current flow through the system. In particular, the influence of
random fluctuations of the underlying lattice on the stationary state
properties is investigated. We show analytically that the steady-state density
presents a linear profile. The local steady-state current obeys the Fourier law
$j=-\kappa(\tau)\nabla \rho $ where $\tau$ is a typical timescale of the
lattice fluctuations and $\nabla \rho$ the density gradient imposed %on the
system by the reservoirs.
\\ ( , 24kb)
Date: Wed, 19 Nov 2008 13:30:45 GMT (13kb)

Title: Coexistence of Non-Conventional Condensates in Two-Level Bose Atom
Authors: M.Corgini, C.Rojas-Molina, D.P.Sankovich
Categories: cond-mat.stat-mech
Comments: 17 pages
Journal-ref: Int.J.Mod.Phys.B, vol.22, No7 (2008) 4799-4815
DOI: 10.1142/S0217979208048796
   In the framework of the Bogolyubov approximation and using the Bogolyubov
inequalities we give a simple proof of the coexistence of two non-conventional
Bose-Einstein condensates in the case of some superstable Bose system whose
atoms have an internal two-level structure and their energy operators in the
second quantized form depend on the number operators only.
\\ ( , 13kb)
Date: Wed, 19 Nov 2008 14:03:56 GMT (114kb)

Title: Statistical Mechanics of systems with long range interactions
Authors: David Mukamel
Categories: cond-mat.stat-mech
Comments: Published in AIP Conference Proceedings 970 "Dynamics and
   Thermodynamics of Systems with Long-Range Interactions: Theory and
   Experiments", Assisi, Italy 4-8 July 2007, editors A. Campa, A. Giansanti, G.
   Morigi and F. Sylos Labini, p. 22 (2008)
   Recent theoretical studies of statistical mechanical properties of systems
with long range interactions are briefly reviewed. In these systems the
interaction potential decays with a rate slower than 1/r^d at large distances r
in d dimensions. As a result, these systems are non-additive and they display
unusual thermodynamic and dynamical properties which are not present in systems
with short range interactions. In particular, the various statistical
mechanical ensembles are not equivalent and the microcanonical specific heat
may be negative. Long range interactions may also result in breaking of
ergodicity, making the maximal entropy state inaccessible from some regions of
phase space. In addition, in many cases long range interactions result in slow
relaxation processes, with time scales which diverge in the thermodynamic
limit. Various models which have been found to exhibit these features are
\\ ( , 114kb)
Date: Wed, 19 Nov 2008 17:35:48 GMT (835kb,D)

Title: Preparation of Decoherence Free Cluster States with Optical
Authors: Liang Jiang, Ana Maria Rey, Oriol Romero-Isart, Juan Jose
   Garcia-Ripoll, Anna Sanpera, Mikhail D. Lukin
Categories: quant-ph
Comments: 17 pages, 12 figures
   We present a protocol to prepare decoherence free cluster states using
ultracold atoms loaded in a two dimensional superlattice. The superlattice
geometry leads to an array of 2*2 plaquettes, each of them holding four
spin-1/2 particles that can be used for encoding a single logical qubit in the
two-fold singlet subspace, insensitive to uniform magnetic field fluctuations
in any direction. Dynamical manipulation of the supperlattice yields distinct
inter and intra plaquette interactions and permits to realize one qubit and two
qubit gates with high fidelity, leading to the generation of universal cluster
states for measurement based quantum computation. Our proposal based on inter
and intra plaquette interactions also opens the path to study polymerized
Hamiltonians which support ground states describing arbitrary quantum circuits.
\\ ( , 835kb)
Date: Wed, 19 Nov 2008 17:17:33 GMT (60kb)

Title: Spin mixing in colliding spinor condensates: formation of an effective
Authors: M. Guilleumas, B. Julia-Diaz, J. Mur-Petit, A. Polls
Categories: quant-ph
Comments: Accepted for publication at the Europhysics Letters
   The dynamics of F=1 spinor condensates initially prepared in a double-well
potential is studied in the mean field approach. It is shown that a small seed
of $m=0$ atoms on a system with initially well separated m=1 and m=-1
condensates has a dramatic effect on their mixing dynamics, acting as an
effective barrier for a remarkably long time. We show that this effect is due
to the spinor character of the system, and provides an observable example of
the interplay between the internal spin dynamics and the macroscopic evolution
of the magnetization in a spinor Bose-Einstein condensate.
\\ ( , 60kb)
Date: Thu, 20 Nov 2008 09:47:56 GMT (552kb)

Title: Gauge-field rotation of 2D exciton Bose condensate in double quantum
   well by radial magnetic field
Authors: E.B. Sonin
Categories: cond-mat.other
Comments: 6 pages, 2 figures
   Here it is shown that a radial magnetic field leads to rotation of a Bose
condensed exciton cloud due to Aharonov-Bohm effect for an electron and a hole
forming an exciton. As in the case of mechanical rotation of superfluids,
rotation is accompanied by penetration of vortices into the cloud at some
critical magnetic field. Penetration of vortices strongly affects the total
intensity and the angular distribution of photoluminescence from the exciton
cloud. This effect can be used for an effective experimental manifestation of
exciton Bose condensation.
\\ ( , 552kb)
Date: Thu, 20 Nov 2008 11:07:43 GMT (261kb)

Title: Role of the attractive intersite interaction in the extended Hubbard
Authors: F. Mancini, F. P. Mancini and A. Naddeo
Categories: cond-mat.str-el cond-mat.stat-mech
Comments: 7 pages, 7 figures. EPJB Topical Issue on Novel Quantum Phases and
   Mesoscopic Physics in Quantum Gases
DOI: 10.1140/epjb/e2008-00399-x
   We consider the extended Hubbard model in the atomic limit on a Bethe lattice
with coordination number z. By using the equations of motion formalism, the
model is exactly solved for both attractive and repulsive intersite potential
V. By focusing on the case of negative V, i.e., attractive intersite
interaction, we study the phase diagram at finite temperature and find, for
various values of the filling and of the on-site coupling U, a phase transition
towards a state with phase separation. We determine the critical temperature as
a function of the relevant parameters, U/|V|, n and z and we find a reentrant
behavior in the plane (U/|V|,T). Finally, several thermodynamic properties are
investigated near criticality.
\\ ( , 261kb)
Date: Thu, 20 Nov 2008 19:36:29 GMT (88kb)

Title: Bloch oscillations in one-dimensional spinor gas
Authors: D.M. Gangardt, A. Kamenev
Categories: cond-mat.stat-mech
Comments: 4 pages, 2 figures
   A force applied to a spin-flipped particle in a one-dimensional spinor gas
may lead to Bloch oscillations of particle's position and velocity. The
existence of Bloch oscillations crucially depends on the viscous friction force
exerted by the rest of the gas on the spin excitation. We evaluate the friction
in terms of the quantum fluid parameters. In particular, we show that the
friction is absent for integrable cases, such as SU(2) symmetric gas of bosons
or fermions. For small deviations from the exact integrability the friction is
very weak, opening the possibility to observe Bloch oscillations.
\\ ( , 88kb)
Date: Thu, 20 Nov 2008 15:12:51 GMT (22kb)

Title: Generalized grand-canonical ensemble theory for interacting
   Bose-Einstein systems
Authors: Alexander Jurisch, Jan-Michael Rost
Categories: cond-mat.stat-mech
Comments: 6 pages, two figures
   We use the maximum information principle to include particle-interaction into
the grand-canonical theory of BECs. The inclusion of the particle-interaction
elucidates why thermodynamic calculations for BECs by the grand-canonical
ensemble for the non-interacting case are in coincidence with up to date
experimental results. However, in our generalized theory we can show that a BEC
experiences a real and abrupt phase-transition in contrast to the smooth
phase-transition predicted by the non-interacting grand-canonical ensemble. In
addition, we discuss possible effects due to a thermal environment and the
experimental probing from a general point of view.
\\ ( , 22kb)
Date: Thu, 20 Nov 2008 15:13:14 GMT (13kb)

Title: Weizsacker energy of unitary Fermi gas in a harmonic trap
Authors: Alexander L. Zubarev
Categories: cond-mat.other
Comments: 11 pages, 1 figure
   The universal method of construction of the rigorous lower bounds to the
Weizsacker energy is presented. We study a few-fermion systemat the unitarity.
Upper and lower bounds to the density functional theory(DFT) ground state
energy within the local density approximation (LDA) aregiven. Therigorous lower
bounds to the accuracy of the method are derived.
\\ ( , 13kb)
arXiv:0811.2400 (*cross-listing*)
Date: Fri, 14 Nov 2008 18:20:29 GMT (308kb)

Title: Solitonic ground states in (color-) superconductivity
Authors: Dominik Nickel, Michael Buballa
Categories: hep-ph cond-mat.supr-con nucl-th
Comments: 24 pages, 18 figures
   We present a general framework for analyzing inhomogeneous (color-)
superconducting phases in mean-field approximation without restriction to the
Ginzburg-Landau approach. As a first application, we calculate real gap
functions with general one-dimensional periodic structures for a
3+1-dimensional toy model having two fermion species. The resulting solutions
are energetically favored against homogeneous superconducting (BCS) and normal
conducting phases in a window for the chemical potential difference which is
about twice as wide as for the most simple plane-wave ansatz ("Fulde-Ferrell
phase"). At the lower end of this window, we observe the formation of a soliton
lattice and a continuous phase transition to the BCS phase. At the higher end
of the window the gap functions are sinusoidal, and the transition to the
normal conducting phase is of first order. We also discuss the quasiparticle
excitation spectrum in the inhomogeneous phase. Finally, we compare the gap
functions with the known analytical solutions of the 1+1-dimensional theory.
\\ ( , 308kb)
Date: Tue, 18 Nov 2008 20:07:13 GMT (725kb)

Title: Entanglement detection
Authors: Otfried G\"uhne, Geza Toth
Categories: quant-ph cond-mat.other physics.optics
Comments: Review article, 86 pages, 22 figures. Comments are welcome!
   How can one prove that a given state is entangled? In this paper we review
different methods that have been proposed for entanglement detection. We first
explain the basic elements of entanglement theory for two or more particles and
then entanglement verification procedures such as Bell inequalities,
entanglement witnesses, the determination of nonlinear properties of a quantum
state via measurements on several copies, and spin squeezing inequalities. An
emphasis is given on the theory and application of entanglement witnesses. We
also discuss several experiments, where some of the presented methods have been
\\ ( , 725kb)
Date: Thu, 20 Nov 2008 09:29:25 GMT (67kb)

Title: Slowly decaying states of three particles with resonant interactions
Authors: F\'elix Werner (LKB - Lhomond)
Categories: quant-ph
   We determine analytically how Efimov trimer states are modified by three-body
losses within the model of Braaten and Hammer. We find a regime where the
energies approach the positive real axis and the decay rates vanish.
\\ ( , 67kb)
Date: Thu, 20 Nov 2008 20:39:04 GMT (1009kb)

Title: Coherent Patterning of Matter Waves with Subwavelength Localization
Authors: J. Mompart, V. Ahufinger, G. Birkl
Categories: quant-ph
Comments: 5 pages, 5 figures
   We introduce the Subwavelength Localization via Adiabatic Passage (SLAP)
technique to coherently achieve state-selective patterning and addressing of
matter waves. The SLAP technique consists in coupling two partially overlapping
and spatially structured laser fields to three internal levels of the matter
wave yielding state-selective localization at those positions where the
adiabatic passage process does not occur. We show that by means of this
technique matter wave localization down to the single nanometer can be
achieved. We analyze in detail the potential implementation of the SLAP
technique for nano-lithography with an atomic beam of metastable Ne* and for
coherent patterning of a two-component 87Rb Bose-Einstein condensate.
\\ ( , 1009kb)
Date: Thu, 20 Nov 2008 14:08:25 GMT (464kb)

Title: Steering Bose-Einstein condensates despite time symmetry
Authors: Dario Poletti, Giuliano Benenti, Giulio Casati, Peter Hanggi, Baowen
Categories: physics.atom-ph
Comments: 4 pages, 6 figures
   We study a Bose-Einstein condensate confined in a quasi-1D toroidal trap and
driven by a space-asymmetric potential, being both periodic and symmetric in
time. The system exhibits a directed current for an ensemble of initial
conditions which are symmetric in space and momentum. This phenomenon occurs
only if the interaction between atoms, treated in mean-field approximation,
exceeds a critical value. Our numerical findings can qualitatively be described
with a three-modes model (TMM). Our results corroborate well with a many-body
study, wherein this directed transport persists over an extended time scale
which increases with increasing atom number.
\\ ( , 464kb)
Date: Thu, 20 Nov 2008 19:04:46 GMT (422kb)

Title: Atomic quasi-Bragg diffraction in a magnetic field
Authors: K.F.E.M. Domen, M.A.H.M. Jansen, W. van Dijk, and K.A.H. van Leeuwen
Categories: physics.atom-ph
Comments: 4 pages, 5 figures
   We report on a new technique to split an atomic beam coherently with an
easily adjustable splitting angle. In our experiment metastable helium atoms in
the |{1s2s}^3S_1 M=1> state diffract from a polarization gradient light field
formed by counterpropagating \sigma^+ and \sigma^- polarized laser beams in the
presence of a homogeneous magnetic field. In the near-adiabatic regime, energy
conservation allows the resonant exchange between magnetic energy and kinetic
energy. As a consequence, symmetric diffraction of |M=0> or |M=-1> atoms in a
single order is achieved, where the order can be chosen freely by tuning the
magnetic field. We present experimental results up to 6th order diffraction (24
\hbar k momentum splitting, i.e., 2.21 m/s in transverse velocity) and present
a simple theoretical model that stresses the similarity with conventional Bragg
scattering. The resulting device constitutes a flexible, adjustable,
large-angle, three-way coherent atomic beam splitter with many potential
applications in atom optics and atom interferometry.
\\ ( , 422kb)
Date: Wed, 19 Nov 2008 14:34:09 GMT (234kb)

Title: Dynamical Theory of Price and Money in Volatile Markets. A Physicist's
   Reaction to Economics
Authors: Karl Svozil
Categories: physics.soc-ph
Comments: 26 p
   The creation and annihilation of money and its economic effects are reviewed.
Economic values appear "in the mind" of the market participants; e.g., by
pretending, maintaining and achieving a particular price for a certain asset.
Upon its creation by banks, this kind of "value phantasy" is converted into
"real money" often in terms of buyer's debt accompanied by a simultaneous
payment of fiat money to the seller. This money is then multiplied on the money
market and is competing against other money supplies for the traded assets,
goods and services, where it may cause dilution, inflation and reallocation of
\\ ( , 234kb)

The replacements:

replaced with revised version Fri, 14 Nov 2008 09:53:23 GMT (110kb)

Title: Three-Body Recombination of Identical Bosons with a Large Positive
   Scattering Length at Nonzero Temperature
Authors: Eric Braaten, H.-W. Hammer, Daekyoung Kang, Lucas Platter
Categories: cond-mat.other hep-ph nucl-th
Comments: 34 pages, 10 figures, published version
Report-no: HISKP-TH-08-01
Journal-ref: Phys.Rev. A 78 (2008) 043605
\\ ( , 110kb)
replaced with revised version Thu, 13 Nov 2008 21:41:21 GMT (185kb)

Title: Point processes in arbitrary dimension from fermionic gases, random
   matrix theory, and number theory
Authors: Salvatore Torquato, A. Scardicchio and Chase E Zachary
Categories: cond-mat.stat-mech math-ph math.MP
Comments: 40 pages, 11 figures, 1 table, iopart; corrected mislabeled section
   numbers and minor typographical issues; minor text changes
\\ ( , 185kb)
replaced with revised version Fri, 14 Nov 2008 04:21:49 GMT (310kb,D)

Title: Multi-Modal Properties and Dynamics of the Gradient Echo Quantum Memory
Authors: G. H\'etet, J. J. Longdell, M. J. Sellars, P. K. Lam, and B. C.
Categories: quant-ph
Comments: 4 pages 3 figures
Journal-ref: Phys. Rev. Lett. 101, 203601 (2008)
DOI: 10.1103/PhysRevLett.101.203601
\\ ( , 310kb)
replaced with revised version Mon, 17 Nov 2008 16:30:21 GMT (328kb)

Title: Interaction induced trapping and pulsed emission of a magnetically
   insensitive Bose-Einstein Condensate
Authors: Stephan Middelkamp, Igor Lesanovsky, Peter Schmelcher
Categories: cond-mat.other
Comments: 5 pages, 4 figures
Journal-ref: EPL, 84 (2008) 40011
DOI: 10.1209/0295-5075/84/40011
\\ ( , 328kb)
arXiv:0804.2678 (*cross-listing*)
replaced with revised version Mon, 17 Nov 2008 15:42:52 GMT (94kb)

Title: Density Functional Theory for non-relativistic Fermions in the Unitarity
Authors: Gautam Rupak and Thomas Schaefer (North Carolina State University)
Categories: nucl-th cond-mat.other
Comments: 17 pages, final version, Nuclear Physics A, in press
\\ ( , 94kb)
replaced with revised version Mon, 17 Nov 2008 14:09:36 GMT (246kb)

Title: Collisional stability of a three-component degenerate Fermi gas
Authors: T. B. Ottenstein, T. Lompe, M. Kohnen, A. N. Wenz and S. Jochim
Categories: cond-mat.other
Journal-ref: PRL 101, 203202 (2008)
DOI: 10.1103/PhysRevLett.101.203202
\\ ( , 246kb)
replaced with revised version Sun, 16 Nov 2008 20:21:35 GMT (167kb)

Title: Polarized superfluidity in the attractive Hubbard model with population
Authors: Tung-Lam Dao, Michel Ferrero, Antoine Georges, Massimo Capone, Olivier
Categories: cond-mat.supr-con cond-mat.str-el
Comments: 4+ pages, 4 figures, new version
\\ ( , 167kb)
replaced with revised version Mon, 17 Nov 2008 18:16:45 GMT (28kb)

Title: Motion of an impurity particle in an ultracold quasi-one-dimensional gas
   of hard-core bosons
Authors: M.D. Girardeau and A. Minguzzi
Categories: cond-mat.other
Comments: 4 pp., 2 figures, revtex4; error in Eq.(6) corrected and derivation
\\ ( , 28kb)
replaced with revised version Mon, 17 Nov 2008 04:12:21 GMT (49kb)

Title: Effect of Induced Spin-Orbit Coupling for Atoms via Laser Fields
Authors: Xiong-Jun Liu, Mario F. Borunda, Xin Liu and Jairo Sinova
Categories: cond-mat.stat-mech cond-mat.mes-hall quant-ph
Comments: 4 pages, 3 figures
\\ ( , 49kb)
replaced with revised version Mon, 17 Nov 2008 12:12:25 GMT (27kb)

Title: Effective theory for the Goldstone field in the BCS-BEC crossover at T=0
Authors: Juan L. Ma\~nes and Manuel A. Valle
Categories: cond-mat.other cond-mat.supr-con hep-th nucl-th
Comments: 27 pages. 4 references added, typos corrected, expanded Section III B
\\ ( , 27kb)
replaced with revised version Sat, 15 Nov 2008 12:52:36 GMT (988kb)

Title: Unusual states of vortex matter in mixtures of Bose--Einstein
   Condensates on rotating optical lattices
Authors: E. K. Dahl, E. Babaev, and A. Sudbo
Categories: cond-mat.stat-mech
Comments: 4 pages, 3 figures. To be published in Physical Review Letters
\\ ( , 988kb)
replaced with revised version Mon, 17 Nov 2008 17:02:30 GMT (175kb)

Title: Feshbach projection-operator formalism to resonance scattering on
   Bargmann-type potentials
Authors: Varvara V. Shamshutdinova, Konstantin N. Pichugin, Ingrid Rotter, and
   Boris F. Samsonov
Categories: quant-ph
Comments: 12 pages, 9 figures
\\ ( , 175kb)
replaced with revised version Tue, 18 Nov 2008 18:51:05 GMT (51kb)

Title: Phase Transitions of S=1 Spinor Condensates in an Optical Lattice
Authors: Daniel Podolsky, Shailesh Chandrasekharan, and Ashvin Vishwanath
Categories: cond-mat.stat-mech cond-mat.str-el hep-lat
Comments: 4 pages, 2 figures; v2 - Improved presentation
\\ ( , 51kb)
replaced with revised version Tue, 18 Nov 2008 16:42:27 GMT (31kb)

Title: Theory of quasi-one dimensional imbalanced Fermi gases
Authors: Erhai Zhao and W. Vincent Liu
Categories: cond-mat.other cond-mat.supr-con
Comments: new expanded version, 8 pages, updated references
\\ ( , 31kb)
replaced with revised version Tue, 18 Nov 2008 15:42:20 GMT (191kb)

Title: Atom Chip Diffraction of Bose-Einstein Condensates: The Role of
   Inter-Atomic Interactions
Authors: T. E. Judd, R. G. Scott, T. M. Fromhold
Categories: cond-mat.other
Comments: 5 pages, 4 figures
Journal-ref: Phys. Rev. A 78, 053623 (2008)
\\ ( , 191kb)
replaced with revised version Wed, 19 Nov 2008 14:58:59 GMT (37kb)

Title: Equation of state and effective mass of the unitary Fermi gas in a 1D
   periodic potential
Authors: Gentaro Watanabe, Giuliano Orso, Franco Dalfovo, Lev P. Pitaevskii,
   Sandro Stringari
Categories: cond-mat.supr-con nucl-th
Comments: 6 pages, 4 figures, to appear in Phys. Rev. A
\\ ( , 37kb)
replaced with revised version Tue, 18 Nov 2008 23:02:05 GMT (43kb)

Title: Enhancement of On-Site Interactions of Tunnelling Ultracold Atoms in
   Optical Potentials using Radio-Frequency Dressing
Authors: Martin Shotter, Dimitrios Trypogeorgos and Christopher Foot
Categories: cond-mat.other
Comments: 5 pages, 2 figures, 6 subfigures
Journal-ref: Phys. Rev. A 78, 051602(R) (2008)
DOI: 10.1103/PhysRevA.78.051602
\\ ( , 43kb)
arXiv:0810.0400 (*cross-listing*)
replaced with revised version Wed, 19 Nov 2008 08:32:05 GMT (96kb)

Title: Strongly interacting Fermi systems in 1/N expansion: From cold atoms to
   color superconductivity
Authors: Hiroaki Abuki and Tomas Brauner
Categories: hep-ph cond-mat.supr-con nucl-th
Comments: 13 pages, REVTeX4, 11 eps figures; v2: reference added, version to
   appear in Phys. Rev. D
\\ ( , 96kb)
replaced with revised version Thu, 20 Nov 2008 16:33:09 GMT (1352kb,D)

Title: Finite Temperature Models of Bose-Einstein Condensation
Authors: Nick P. Proukakis and Brian Jackson
Categories: cond-mat.other
Comments: Detailed Review Article on finite temperature theoretical techniques
   for studying weakly-interacting atomic Bose-Einstein condensates written at
   an elementary level suitable for non-experts in this area (e.g. starting PhD
   students). Now includes table of contents
Journal-ref: J. Phys. B: At. Mol. Opt. Phys. 41, 203002 (2008)
\\ ( , 1352kb)

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 Thu Dec 04 2008 - 10:35:40 EST

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