# Matt's arXiv selection: week ending 8th June 2007.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Thu, 14 Jun 2007 21:38:43 +1000 (EST)

The following message was sent to the matts_arxiv list by Matthew Davis <mdavis_at_physics.uq.edu.au>

Hi everyone,

Late again, this time because I have been travelling. I have just been at a
very interesting conference in Denmark on non-equilibrium dynamics of finite
temperature superfluids, which was for theorists only - you should have seen all
the equations. Special thanks to Ana-Marie Rey, Tom Hanna, and Simon Gardiner
who all bought me a beer in appreciation of this email!

A largish 32 new abstracts and 9 replacements last week.

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arXiv:0706.0032
Date: Thu, 31 May 2007 22:47:41 GMT (276kb)

Title: Bifurcations and bistability in cavity assisted photoassociation of
Bose-Einstein condensed molecules
Authors: Markku Jaaskelainen, Jaeyoon Jeong, and Christopher P. Search
Categories: cond-mat.other
\\
We study the photo-association of Bose-Einstein condensed atoms into
molecules using an optical cavity field. The driven cavity field introduces a
new dynamical degree of freedom into the photoassociation process, whose role
in determining the stationary behavior has not previously been considered. The
semiclassical stationary solutions for the atom and molecules as well as the
intracavity field are found and their stability and scaling properties are
determined in terms of experimentally controllable parameters including driving
amplitude of the cavity and the nonlinear interactions between atoms and
molecules. For weak cavity driving, we find a bifurcation in the atom and
molecule number occurs that signals a transition from a stable steady state to
nonlinear Rabi oscillations. For a strongly driven cavity, there exists
bistability in the atom and molecule number.
\\ ( http://arxiv.org/abs/0706.0032 , 276kb)
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arXiv:0706.0079
Date: Fri, 1 Jun 2007 14:35:23 GMT (592kb)

Title: Delocalizing transition in one-dimensional condensates in optical
lattices due to inhomogeneous interactions
Authors: Yu. V. Bludov, V. A. Brazhnyi, V. V. Konotop
Categories: cond-mat.other
\\
It is shown that inhomogeneous nonlinear interactions in a Bose-Einstein
condensate loaded in an optical lattice can result in delocalizing transition
in one dimension, what sharply contrasts to the known behavior of discrete and
periodic systems with homogeneous nonlinearity. The transition can be
originated either by decreasing the amplitude of the linear periodic potential
or by the change of the mean value of the periodic nonlinearity. The dynamics
of the delocalizing transition is studied.
\\ ( http://arxiv.org/abs/0706.0079 , 592kb)
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arXiv:0706.0094
Date: Fri, 1 Jun 2007 08:44:50 GMT (312kb)

Title: Mean field theory of spin glasses: statics and dynamics
Authors: Giorgio Parisi
Categories: cond-mat.dis-nn cond-mat.stat-mech
Comments: 40 pages, 6 figures; proceedings of The 2006 Les Houches Summer
School
\\
In these lectures I will review some theoretical results that have been
obtained for spin glasses. I will concentrate my attention on the formulation
of the mean field approach and on its numerical and experimental verifications.
I will present the various hypothesis at the basis of the theory and I will
discuss their mathematical and physical status.
\\ ( http://arxiv.org/abs/0706.0094 , 312kb)
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arXiv:0705.3376
Date: Wed, 23 May 2007 13:51:46 GMT (214kb)

Title: Gaussian number-squeezed states for sub-shot-noise interferometery in
double-well Bose-Einstein condensates
Authors: Y. P. Huang and M. G. Moore
Categories: quant-ph cond-mat.other
\\
We show that a Mach-Zender interferometer with a gaussian number-squeezed
input state can exhibit sub-shot-noise phase resolution over a large range of
measured phase-shifts in a single measurement. In contrast, previously studied
input states are shown to degrade quickly to worse than shot-noise when a
non-zero phase-shift is measured. This interferometer can be implemented in a
double-well Bose-Einstein condensate system, and the gaussian squeezed states
can obtained via adiabatic manipulation of the ground state in the presence of
repulsive atomic interactions. From Bayesian analysis, we find that the
phase-estimation uncertainty scales as 1/N at zero phase, and crosses over
smoothly to the shot-noise limit $1/\sqrt{N}$ as the phase approaches
$\pm\pi/2$.
\\ ( http://arxiv.org/abs/0705.3376 , 214kb)
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arXiv:0705.4647
Date: Thu, 31 May 2007 18:59:12 GMT (89kb)

Title: Bell's inequality and universal quantum gates in a cold atom chiral
fermionic p-wave superfluid
Authors: Chuanwei Zhang, Sumanta Tewari, S. Das Sarma
Categories: quant-ph cond-mat.str-el
\\
We propose and analyze a probabilistic scheme to entangle two spatially
separated topological qubits in a $p_{x}+ip_{y}$ superfluid using controlled
collisions between atoms in movable dipole traps and unpaired atoms inside
vortex cores in the superfluid. We discuss how to test the violation of Bell's
inequality with the generated entanglement. A set of universal quantum gates is
shown to be implementable \textit{deterministically} using the entanglement
despite the fact that the entangled states can only be created
probabilistically.
\\ ( http://arxiv.org/abs/0705.4647 , 89kb)
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arXiv:0706.0062
Date: Fri, 1 Jun 2007 04:59:15 GMT (95kb)

Title: Teleportation of massive particles without shared entanglement
Authors: A. S. Bradley and M. K. Olsen and S. A. Haine and J. J. Hope
Categories: quant-ph
\\
We propose a method for quantum state transfer from one atom laser beam to
another via an intermediate optical field, using Raman incoupling and
outcoupling techniques. Our proposal utilises existing experimental
technologies to teleport macroscopic matter waves over potentially large
distances without shared entanglement.
\\ ( http://arxiv.org/abs/0706.0062 , 95kb)
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arXiv:0706.0110
Date: Fri, 1 Jun 2007 09:30:29 GMT (91kb)

Title: Spatially resolved observation of dipole-dipole interaction between
Rydberg atoms
Authors: C. S. E. van Ditzhuijzen, A. F. Koenderink, J. V. Hern\'andez, F.
Robicheaux, L. D. Noordam and H. B. van Linden van den Heuvell
Categories: quant-ph
\\
We have observed resonant energy transfer between cold Rydberg atoms in
spatially separated cylinders. After laser preparation, resonant dipole-dipole
coupling at 33 GHz ($\lambda$ = 1.1 cm) excites the 49s atoms in one cylinder
to the 49p state while the 41d atoms in the second cylinder decay to 42p. We
have measured the production of the 49p state as a function of separation of
the cylinders (0 - 70 $\mu$m) and the interaction time (0 - 25 $\mu$s), all for
cylinders with a radius of 5 $\mu$m. In addition we measured the width of the
electric field resonances. A full many-body quantum calculation reproduces the
main features of the experiments.
\\ ( http://arxiv.org/abs/0706.0110 , 91kb)
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arXiv:0706.0212
Date: Fri, 1 Jun 2007 20:06:17 GMT (113kb)

Title: Breakdown of the adiabatic limit in low dimensional gapless systems
Authors: Anatoli Polkovnikov and Vladimir Gritsev
Categories: cond-mat.stat-mech cond-mat.dis-nn
\\
It is generally believed that a generic system can be reversibly transformed
from one state into another by sufficiently slow change of parameters and that
the entropy of the system is conserved in such a slow (adiabatic) process. A
standard argument favoring this assertion is based on possibility of the
expansion of the energy, entropy, number of excitations (quasi-particles) or
other thermodynamic quantities into the Taylor series in the ramp speed
$\delta$. In this paper we examine this assertion for gapless systems. We show
that the general argumentation is indeed valid at high enough dimensions.
However, in low dimensional gapless systems it can break down. We identify
three possible generic regimes of a system response to a slow ramp: ({\bf A})
mean-field, where the energy density in the final state $\mathcal E$ is an
analytic function of $\delta$: $\mathcal E(\delta)\approx \mathcal E_0+\beta \delta^2$, ({\bf B}) non-analytic, where $\mathcal E(\delta)\approx \mathcal E_0+\beta|\delta|^\nu$ with some universal power $\nu<2$, and ({\bf C})
non-adiabatic, where $\mathcal E(\delta)\approx \mathcal E_0+\beta|\delta|^\nu L^\eta$ with $L$ being the system size. In the third regime the limits
$\delta\to 0$ and $L\to\infty$ do not commute and the adiabatic process does
not exist for large enough $L$. Our analysis directly applies to integrable and
weakly nonintegrable systems. In the latter case, if the system is allowed to
re-thermalize at long times then regimes {\bf A}, {\bf B}, and {\bf C} apply to
the entropy and the temperature of the system. We give specific examples where
all three regimes are realized and support our results by numerical
simulations. Our results can be relevant to condensed-matter and atomic
physics, quantum computing, quantum optics, inflationary cosmology and others.
\\ ( http://arxiv.org/abs/0706.0212 , 113kb)
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arXiv:0706.0240
Date: Fri, 1 Jun 2007 23:32:30 GMT (114kb)

Title: KRb Feshbach Resonances: Modeling the interatomic potential
Authors: C. Klempt, T. Henninger, O. Topic, J. Will, W. Ertmer, E. Tiemann and
J. Arlt
Categories: cond-mat.other
\\
We have observed 28 heteronuclear Feshbach resonances in 10 spin combinations
of the hyperfine ground states of a 40K 87Rb mixture. The measurements were
performed by observing the loss rates from an atomic mixture at magnetic fields
between 0 and 700 G. This data was used to significantly refine an interatomic
potential derived from molecular spectroscopy, yielding a highly consistent
model of the KRb interaction. Thus, the measured resonances can be assigned to
the corresponding molecular states. In addition, this potential allows for an
accurate calculation of the energy differences between highly excited levels
and the rovibrational ground level. This information is of particular relevance
for the formation of deeply bound heteronuclear molecules. Finally, the model
is used to predict Feshbach resonances in mixtures of 87Rb combined with 39K or
41K.
\\ ( http://arxiv.org/abs/0706.0240 , 114kb)
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arXiv:0706.0244
Date: Sat, 2 Jun 2007 00:31:30 GMT (26kb)

Title: Bose-Einstein condensation and Superfluidity of magnetoexcitons in
Graphene
Authors: Oleg L. Berman, Yurii E. Lozovik, and Godfrey Gumbs
Categories: cond-mat.str-el cond-mat.mes-hall
\\
We propose experiments to observe Bose-Einstein condensation (BEC) and
superfluidity of quasi-two-dimensional (2D) spatially indirect magnetoexcitons
in bilayer graphene. The magnetic field $B$ is assumed strong. The energy
spectrum of collective excitations, the sound spectrum as well as the effective
magnetic mass of magnetoexcitons are presented in the strong magnetic field
regime. The superfluid density $n_S$ and the temperature of the
Kosterlitz-Thouless phase transition $T_c$ are shown to be increasing functions
of the excitonic density $n$ but decreasing functions of $B$ and the interlayer
separation $D$. Numerical results are presented from these calculations.
\\ ( http://arxiv.org/abs/0706.0244 , 26kb)
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arXiv:0706.0414
Date: Mon, 4 Jun 2007 15:33:57 GMT (38kb)

Title: Engineered quantum tunnelling in extended periodic potentials
Authors: Sandro Wimberger, Donatella Ciampini, Oliver Morsch, Riccardo
Mannella, and Ennio Arimondo
Categories: cond-mat.other
Comments: 6 pp, proceedings DICE 11-15 September 2006, Castello di Piombino,
Tuscany, Italy
Journal-ref: 2007 J. Phys.: Conf. Ser. 67 012060 (6pp)
DOI: 10.1088/1742-6596/67/1/012060
\\
Quantum tunnelling from a tilted, but otherwise periodic potential is
studied. Our theoretical and experimental results show that, by controlling the
system's parameters, we can engineer the escape rate of a Bose-Einstein
condensate to an exceptional degree. Possible applications of this atom-optics
realization of the open Wannier-Stark system are discussed.
\\ ( http://arxiv.org/abs/0706.0414 , 38kb)
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arXiv:0706.0477
Date: Mon, 4 Jun 2007 16:35:29 GMT (234kb)

Title: Polarisation rotation of slow light with orbital angular momentum in
ultracold atomic gases
Authors: J. Ruseckas, G. Juzeliunas, P. Ohberg and S.M. Barnett
Categories: cond-mat.other
\\
We consider the propagation of slow light with an orbital angular momentum
(OAM) in a moving atomic medium. We have derived a general equation of motion
and applied it in analysing propagation of slow light with an OAM in a rotating
medium, such as a vortex lattice. We have shown that the OAM of slow light
manifests itself in a rotation of the polarisation plane of linearly polarised
light. To extract a pure rotational phase shift, we suggest to measure a
difference in the angle of the polarisation plane rotation by two consecutive
light beams with opposite OAM. The differential angle $\Delta\alpha_{\ell}$ is
proportional to the rotation frequency of the medium $\omega_{\mathrm{rot}}$
and the winding number $\ell$ of light, and is inversely proportional to the
group velocity of light. For slow light the angle $\Delta\alpha_{\ell}$ should
be large enough to be detectable. The effect can be used as a tool for
measuring the rotation frequency $\omega_{\mathrm{rot}}$ of the medium.
\\ ( http://arxiv.org/abs/0706.0477 , 234kb)
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arXiv:0705.3268
Date: Wed, 23 May 2007 00:09:22 GMT (216kb)

Title: Atomtronic circuits of diodes and transistors
Authors: R. A. Pepino, J. Cooper, D. Z. Anderson & M. J. Holland
Categories: physics.atom-ph cond-mat.other
\\
In this letter, we illustrate that open quantum systems composed of neutral,
ultracold atomic gases trapped in optical lattices can exhibit analogous
behavior to semiconductor electronic circuits. A precise, physically-attainable
correspondence is demonstrated and the experimental parameters needed to
realize the behavior of semiconductor diodes and transistors are presented. Our
analysis follows from our formulation of a modified master equation approach to
this general class of open quantum systems.
\\ ( http://arxiv.org/abs/0705.3268 , 216kb)
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arXiv:0706.0237
Date: Fri, 1 Jun 2007 22:58:27 GMT (13kb)

Title: Quantum Mechanics in Phase Space
Categories: quant-ph
\\
In this paper, I am presenting the basics of the Wigner formulation of
Quantum-Mechanics in a very simple language and writing about few
interpretational stuff arised around it.
\\ ( http://arxiv.org/abs/0706.0237 , 13kb)
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arXiv:0706.0425
Date: Mon, 4 Jun 2007 12:47:10 GMT (188kb)

Title: Two-mode single-atom laser as a source of entangled light
Authors: M. Kiffner, M. S. Zubairy, J. Evers and C. H. Keitel
Categories: quant-ph
Journal-ref: Phys. Rev. A 75, 033816 (2007)
\\
A two-mode single-atom laser is considered, with the aim of generating
entanglement in macroscopic light. Two transitions in the four-level gain
medium atom independently interact with the two cavity modes, while two other
transitions are driven by control laser fields. Atomic relaxation as well as
cavity losses are taken into account. We show that this system is a source of
macroscopic entangled light over a wide range of control parameters and initial
states of the cavity field.
\\ ( http://arxiv.org/abs/0706.0425 , 188kb)
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arXiv:0706.0584
Date: Tue, 5 Jun 2007 05:34:32 GMT (893kb)

Title: Rotation of an atomic Bose-Einstein condensate with and without a
quantized vortex
Authors: I. Corro, N. G. Parker and A. M. Martin
Categories: cond-mat.other
\\
We theoretically examine the rotation of an atomic Bose-Einstein condensate
in an elliptical trap, both in the absence and presence of a quantized vortex.
Two methods of introducing the rotating potential are considered -
adiabatically increasing the rotation frequency at fixed ellipticity, and
adiabatically increasing the trap ellipticity at fixed rotation frequency.
Extensive simulations of the Gross-Pitaevskii equation are employed to map out
the points where the condensate becomes unstable and ultimately forms a vortex
lattice. We highlight the key features of having a quantized vortex in the
initial condensate. In particular, we find that the presence of the vortex
causes the instabilities to shift to lower or higher rotation frequencies,
depending on the direction of the vortex relative to the trap rotation.
\\ ( http://arxiv.org/abs/0706.0584 , 893kb)
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arXiv:0706.0601
Date: Tue, 5 Jun 2007 08:36:00 GMT (697kb)

Title: Dark solitons in a superfluid Fermi gas
Authors: Mauro Antezza, Franco Dalfovo, Lev P. Pitaevskii, Sandro Stringari
Categories: cond-mat.stat-mech cond-mat.supr-con
\\
We investigate the behavior of dark solitons in a superfluid Fermi gas along
the BCS-BEC crossover by solving the Bogoliubov - de Gennes equations and
looking for real and odd solutions for the order parameter. We show that in the
resonance unitary region, where the scattering length is large, the density
profile of the soliton has a deep minimum, differently from what happens in the
BCS regime. The superfluid gap is found to be significantly quenched by the
presence of the soliton due to the occurrence of Andreev fermionic bound states
localized near the nodal plane of the order parameter.
\\ ( http://arxiv.org/abs/0706.0601 , 697kb)
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arXiv:0706.0609
Date: Tue, 5 Jun 2007 09:08:17 GMT (49kb)

Title: Molecular superfluid phase in one-dimensional multicomponent fermionic
cold atoms
Authors: S. Capponi, G. Roux, P. Lecheminant, P. Azaria, E. Boulat, S. R. White
Categories: cond-mat.str-el
\\
We study a simple model of N-component fermions with contact interactions
which describes fermionic atoms with N=2F+1 hyperfine states loaded into a
one-dimensional optical lattice. We show by means of analytical and numerical
approaches that, for attractive interaction, a quasi-long-range molecular
superfluid phase emerges at low density. In such a phase, the pairing
instability is strongly suppressed and the leading instability is formed from
\\ ( http://arxiv.org/abs/0706.0609 , 49kb)
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arXiv:0706.0629
Date: Tue, 5 Jun 2007 11:48:42 GMT (8kb)

Title: Quasi localization and quasi mobility edge for the light fermionic atoms
mixed with the heavy ones
Authors: E. Kogan
Categories: cond-mat.dis-nn
Comments: 4 pages, 1 figure, latex
\\
A mixture of light and heavy spin-polarized fermionic atoms is considered. We
study kinetics of light atoms, scattered by heavy ones, the latter undergoing
slow diffusive motion. In a three-dimensional space we claim the existence of
the crossover region (on the energy axis), which separates the states of the
light atoms with fast diffusion and the states with slow diffusion; the latter
is determined by the dephasing time. In a two-dimensional space the diffusion
coefficient for any value of energy is determined by the dephasing time.
\\ ( http://arxiv.org/abs/0706.0629 , 8kb)
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arXiv:0706.0709
Date: Tue, 5 Jun 2007 17:24:46 GMT (32kb)

Title: Spin-charge separation in two-component Bose-gases
Authors: A. Kleine, C. Kollath, I. McCulloch, T. Giamarchi, and U. Schollwoeck
Categories: cond-mat.other
\\
We show that one of the key characteristics of interacting one-dimensional
electronic quantum systems, the separation of spin and charge, can be observed
in a two-component system of bosonic ultracold atoms even close to a competing
phase separation regime. To this purpose we determine the real-time evolution
of a single particle excitation and the single-particle spectral function using
density-matrix renormalization group techniques. Due to efficient bosonic
cooling and good tunability this setup exhibits very good conditions for
observing this strong correlation effect. In anticipation of experimental
realizations we calculate the velocities for spin and charge perturbations for
a wide range of parameters.
\\ ( http://arxiv.org/abs/0706.0709 , 32kb)
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arXiv:0706.0528
Date: Mon, 4 Jun 2007 20:24:21 GMT (146kb)

Title: Heralded Entanglement between Atomic Ensembles: Preparation,
Decoherence, and Scaling
Authors: J. Laurat, K. S. Choi, H. Deng, C. W. Chou, H. J. Kimble
Categories: quant-ph
\\
Heralded entanglement between collective excitations in two atomic ensembles
is probabilistically generated, stored, and then converted to single photon
fields. By way of the measured concurrence, quantitative characterizations are
reported for the scaling behavior of entanglement with excitation probability
and for the temporal dynamics of various correlations that result in the decay
of entanglement. A lower bound of the concurrence for the collective atomic
state of $0.9\pm 0.3$ is inferred. An abrupt loss of entanglement as a function
of storage time is also observed, and the relationship to the phenomenon
"entanglement sudden death" analyzed.
\\ ( http://arxiv.org/abs/0706.0528 , 146kb)
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arXiv:0706.0757
Date: Wed, 6 Jun 2007 15:15:10 GMT (673kb)

Title: Fractional Quantum Hall Effect in Optical Lattices
Authors: Mohammad Hafezi, Anders S. Sorensen, Eugene Demler, Mikhail D. Lukin
Categories: cond-mat.mes-hall
\\
We analyze a recently proposed method to create fractional quantum Hall (FQH)
states of atoms confined in optical lattices [A. S{\o}rensen {\it et al.},
Phys. Rev. Lett. {\bf 94} 086803 (2005)]. Extending the previous work, we
investigate conditions under which the FQH effect can be achieved for bosons on
a lattice with an effective magnetic field and finite onsite interaction.
Furthermore, we characterize the ground state in such systems by calculating
Chern numbers which can provide direct signatures of topological order and
explore regimes where the characterization in terms of wavefunction overlap
fails. We also discuss various issues which are relevant for the practical
realization of such FQH states with ultracold atoms in an optical lattice,
including the presence of the long-range dipole interaction which can improve
the energy gap and stabilize the ground state. We also investigate a new
detection technique based on Bragg spectroscopy to probe these system in an
experimental realization.
\\ ( http://arxiv.org/abs/0706.0757 , 673kb)
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arXiv:0706.0759
Date: Wed, 6 Jun 2007 03:51:08 GMT (365kb)

Title: Vortex Lattice Structures of a Bose-Einstein Condensate in a Rotating
Triangular Lattice Potential
Authors: T. Sato, T. Ishiyama, and T. Nikuni
Categories: cond-mat.other
\\
We study the vortex pinning effect in a Bose-Einstein Condensate in the
presence of a rotating lattice potential by numerically solving the
time-dependent Gross-Pitaevskii equation. We consider a triangular lattice
potential created by blue-detuned laser beams. By rotating the lattice
potential, we observe a transition from the Abrikosov vortex lattice to the
pinned vortex lattice. We investigate the transition of the vortex lattice
structure by changing conditions such as angular velocity, strength, and
lattice constant of a rotating lattice potential. Our simulation results
clearly show that the lattice potential has a strong vortex pinning effect when
the vortex density coincides with the density of the pinning points.
\\ ( http://arxiv.org/abs/0706.0759 , 365kb)
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arXiv:0706.0823
Date: Wed, 6 Jun 2007 13:38:46 GMT (593kb)

Title: Dynamics of Localization Phenomena for Hardcore Bosons in Optical
Lattices
Authors: Birger Horstmann, Juan Ignacio Cirac, Tommaso Roscilde
Categories: cond-mat.str-el cond-mat.dis-nn
\\
We investigate the behavior of ultracold bosons in optical lattices with a
disorder potential generated via a secondary species frozen in random
configurations. The statistics of disorder is associated with the physical
state in which the secondary species is prepared. The resulting random
potential, albeit displaying algebraic correlations, is found to lead to
localization of all single-particle states. We then investigate the real-time
dynamics of localization for a hardcore gas of mobile bosons which are brought
into sudden interaction with the random potential. Regardless of their initial
state and for any disorder strength, the mobile particles are found to reach a
steady state characterized by exponentially decaying off-diagonal correlations
and by the absence of quasi-condensation; when the mobile particles are
initially confined in a tight trap and then released in the disorder potential,
their expansion is stopped and the steady state is exponentially localized in
real space, clearly revealing Anderson localization.
\\ ( http://arxiv.org/abs/0706.0823 , 593kb)
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arXiv:0706.0834
Date: Wed, 6 Jun 2007 14:28:11 GMT (13kb)

Title: Resonant scattering of ultracold atoms in low dimensions
Authors: Ludovic Pricoupenko (LPTMC)
Categories: cond-mat.other
Proxy: ccsd hal-00152359
\\
Low energy scattering amplitudes for two atoms in one- and two-dimensional
atomic wave guides are derived for short range isotropic and resonant
interactions in high partial wave channels. Taking into account the finite
width of the resonances which cannot be set arbitrarily to zero is shown to
have important implications for the confinement induced resonances. For spin
polarized fermions in a linear wave guide in the limit of infinitely strong
odd-wave scattering length it imposes a strong constraint for achieving the
Fermi Tonks Girardeau gas. For a planar wave guide, the $p$- and d-wave
scattering resonances are analyzed in terms of the appearance of a low energy
quasi-bound state.
\\ ( http://arxiv.org/abs/0706.0834 , 13kb)
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arXiv:0706.0839
Date: Wed, 6 Jun 2007 15:21:11 GMT (117kb)

Title: Correlated bosons on a lattice: Dynamical mean-field theory for
Bose-Einstein condensed and normal phases
Authors: Krzysztof Byczuk and Dieter Vollhardt
Categories: cond-mat.other
\\
The observation of Bose-Einstein condensation (BEC) in ultra-cold, atomic
gases has greatly stimulated research into the properties of this fascinating
quantum state of matter. In particular, experiments with alkali atoms confined
in optical lattices have renewed the theoretical interest in the physics of
strongly correlated bosons on lattices, which promises significant new insights
and even applications in fields such as quantum computing. In this paper we
formulate the first comprehensive, thermodynamically consistent theory of
correlated lattice boson systems, namely a bosonic dynamical mean-field theory
(B-DMFT) which is applicable for arbitrary values of the coupling parameters
and temperature. B-DMFT includes all local, dynamical correlations of the
many-boson system and becomes exact in the limit of infinite space dimensions
in analogy with its successful fermionic counterpart. With B-DMFT we are able
to solve a lattice model of itinerant and localised, interacting bosons
analytically. The local correlations lead to an unexpected \emph{enhancement}
both of the BEC transition temperature $T_{BEC}$ and the condensate fraction as
compared to the non-interacting system. Hence bosonic correlations can be
employed in the laboratory to reach higher values of $T_{BEC}$.
\\ ( http://arxiv.org/abs/0706.0839 , 117kb)
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arXiv:0706.0796
Date: Wed, 6 Jun 2007 10:32:09 GMT (333kb)

Title: Continuous loading of $^{1}$S$_{0}$ calcium atoms into an optical dipole
trap
Authors: C. Y. Yang, P. Halder, O. Appel, D. Hansen, A. Hemmerich
Categories: physics.atom-ph
\\
spatially selective optical pumping. We discuss the case of $^{1}$S$_{0}$
calcium atoms in an optical dipole trap (ODT), however, similar strategies
should be applicable to a wide range of atomic species. Our starting point is a
reservoir of moderately cold ($\approx 300 \mu$K) metastable
$^{3}$P$_{2}$-atoms prepared by means of a magneto-optic trap (triplet-MOT). A
focused 532 nm laser beam produces a strongly elongated optical potential for
$^{1}$S$_{0}$-atoms with up to 350 $\mu$K well depth. A weak focused laser beam
at 430 nm, carefully superimposed upon the ODT beam, selectively pumps the
$^{3}$P$_{2}$-atoms inside the capture volume to the singlet state, where they
are confined by the ODT. The triplet-MOT perpetually refills the capture volume
with $^{3}$P$_{2}$-atoms thus providing a continuous stream of cold atoms into
the ODT at a rate of $10^7$s$^{-1}$. Limited by evaporation loss, in 200 ms we
typically load $5 \times 10^5$ atoms with an initial radial temperature of 85
$\mu$K. After terminating the loading we observe evaporation during 50 ms
leaving us with $10^5$ atoms at radial temperatures close to 40 $\mu$K and a
peak phase space density of $6.8 \times 10^{-5}$. We point out that a
comparable scheme could be employed to load a dipole trap with
$^{3}$P$_{0}$-atoms.
\\ ( http://arxiv.org/abs/0706.0796 , 333kb)
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arXiv:0706.0837
Date: Wed, 6 Jun 2007 14:58:32 GMT (173kb)

Title: Saturation effects in the sub-Doppler spectroscopy of Cesium vapor
confined in an Extremely Thin Cell
Authors: C. Andreeva, S. Cartaleva, L. Petrov, S. M. Saltiel, D. Sarkisyan,
T.Varzhapetyan, D. Bloch, M. Ducloy
Categories: physics.class-ph
\\
Saturation effects affecting absorption and fluorescence spectra of an atomic
vapor confined in an Extremely Thin Cell (cell thickness $L < 1 \mu m$) are
investigated experimentally and theoretically. The study is performed on the
$D_{2}$ line ($\lambda ~= ~852 nm)$ of $Cs$ and concentrates on the two
situations $L = \lambda /2$ and $L =\lambda$, the most contrasted ones with
respect to the length dependence of the coherent Dicke narrowing. For $L = \lambda /2$, the Dicke-narrowed absorption profile simply broadens and
saturates in amplitude when increasing the light intensity, while for $L =\lambda$, sub-Doppler dips of reduced absorption at line-center appear on the
broad absorption profile. For a fluorescence detection at $L =\lambda$,
saturation induces narrow dips, but only for hyperfine components undergoing a
population loss through optical pumping. These experimental results are
interpreted with the help of the various existing models, and are compared with
numerical calculations based upon a two-level modelling that considers both a
closed and an open system.
\\ ( http://arxiv.org/abs/0706.0837 , 173kb)
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\\
arXiv:0706.0959
Date: Thu, 7 Jun 2007 09:36:01 GMT (627kb,D)

Title: Quantum Field Theoretical Analysis on Unstable Behavior of Bose-Einstein
Condensates in Optical Lattices
Authors: K.Kobayashi, M.Mine, M.Okumura and Y.Yamanaka
Categories: cond-mat.other
\\
We study the dynamics of Bose-Einstein condensates flowing in optical
lattices on the basis of quantum field theory. For such a system, a
Bose-Einstein condensate shows a unstable behavior which is called the
dynamical instability. The unstable system is characterized by the appearance
of modes with complex eigenvalues. Expanding the field operator in terms of
excitation modes including complex ones, we attempt to diagonalize the
unperturbative Hamiltonian and to find its eigenstates. It turns out that
although the unperturbed Hamiltonian is not diagonalizable in the conventional
bosonic representation the appropriate choice of physical states leads to a
consistent formulation. Then we analyze the dynamics of the system in the
regime of the linear response theory. Its numerical results are consitent with
as those given by the discrete nonlinear Schrodinger equation.
\\ ( http://arxiv.org/abs/0706.0959 , 627kb)
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\\
arXiv:0706.1041
Date: Thu, 7 Jun 2007 17:08:30 GMT (606kb)

Title: Spectroscopy of Ultracold, Trapped Cesium Feshbach Molecules
Authors: M. Mark, F. Ferlaino, S. Knoop, J.G. Danzl, T. Kraemer, C. Chin, H.-C.
Naegerl, R. Grimm
Categories: cond-mat.other
Comments: 15 pages, 12 figures, 4 tables
\\
We explore the rich internal structure of Cs_2 Feshbach molecules. Pure
ultracold molecular samples are prepared in a CO_2-laser trap, and a multitude
of weakly bound states is populated by elaborate magnetic-field ramping
techniques. Our methods use different Feshbach resonances as input ports and
various internal level crossings for controlled state transfer. We populate
higher partial-wave states of up to eight units of rotational angular momentum
(l-wave states). We investigate the molecular structure by measurements of the
magnetic moments for various states. Avoided level crossings between different
molecular states are characterized through the changes in magnetic moment and
by a Landau-Zener tunneling method. Based on microwave spectroscopy, we present
a precise measurement of the magnetic-field dependent binding energy of the
weakly bound s-wave state that is responsible for the large background
scattering length of Cs. This state is of particular interest because of its
quantum-halo character.
\\ ( http://arxiv.org/abs/0706.1041 , 606kb)
------------------------------------------------------------------------------
\\
arXiv:0706.1005
Date: Thu, 7 Jun 2007 19:14:07 GMT (413kb)

Title: Measurement of Intracavity Quantum Fluctuations of Light Using an Atomic
Fluctuation Bolometer
Authors: Kater W. Murch, Kevin L. Moore, Subhadeep Gupta, and Dan M.
Stamper-Kurn
Categories: quant-ph
\\
The spectral noise power of photon number fluctuations inside a driven
high-finesse Fabry-Perot optical resonator is measured through the
resonator-enhanced momentum diffusion of ultracold atoms trapped within.
Light-induced heating of the trapped atoms is quantified by their rate of
evaporation from a finite-depth intracavity optical trap. The relevance of
cavity-enhanced momentum diffusion to cavity-enhanced measurements of atomic
ensembles is discussed.
\\ ( http://arxiv.org/abs/0706.1005 , 413kb)
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\\
arXiv:0706.1052
Date: Thu, 7 Jun 2007 19:09:19 GMT (262kb)

Title: Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic
Motion
Authors: Subhadeep Gupta, Kevin L. Moore, Kater W. Murch and Dan M.
Stamper-Kurn
Categories: quant-ph
\\
We report on nonlinear optical phenomena caused by the collective motion of
ultracold atoms within a Fabry-Perot cavity in a regime of single-atom strong
coupling. Up to $10^5$ rubidium atoms are trapped in the lowest band of a
one-dimensional intracavity optical lattice. We observe large Kerr nonlinearity
and dispersive optical bistability arising from probe-induced displacement of
the trapped atoms. The longevity of atomic motional coherence allows for
strongly nonlinear optics at extremely low cavity photon numbers, as
demonstrated by the observation of both branches of optical bistability at
photon numbers below unity.
\\ ( http://arxiv.org/abs/0706.1052 , 262kb)
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The replacments:

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\\
arXiv:0704.2155
replaced with revised version Fri, 1 Jun 2007 11:46:55 GMT (66kb)

Title: Atom-molecule Rabi oscillations in a Mott insulator
Authors: N. Syassen, D. M. Bauer, M. Lettner, D. Dietze, T. Volz, S. D\"urr,
and G. Rempe
Categories: cond-mat.stat-mech
\\ ( http://arxiv.org/abs/0704.2155 , 66kb)
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\\
arXiv:quant-ph/0607069
replaced with revised version Fri, 1 Jun 2007 13:33:17 GMT (66kb)

Title: Spatial Entanglement of a Free Bosonic Field
Authors: L. Heaney, J. Anders, V. Vedral
Categories: quant-ph
Comments: 5 pages, 4 figures, extended version of the paper from 5 to 8 pages.
We have included a more detailed discussion and added new results that
support our original conclusions
\\ ( http://arxiv.org/abs/quant-ph/0607069 , 66kb)
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\\
arXiv:physics/0703136
replaced with revised version Fri, 1 Jun 2007 08:56:33 GMT (329kb)

Title: Interactions and dynamics in Li + Li_2 ultracold collisions
Authors: Marko T. Cvitas, Pavel Soldan, Jeremy M. Hutson, Pascal Honvault and
Jean-Michel Launay
Categories: physics.chem-ph physics.atom-ph
Comments: 21 pages, 27 figures. Version 2 is final version as accepted for
publication in J. Chem. Phys
\\ ( http://arxiv.org/abs/physics/0703136 , 329kb)
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\\
arXiv:cond-mat/0606043
replaced with revised version Mon, 4 Jun 2007 07:05:32 GMT (560kb)

Title: Zero Temperature Thermodynamics of Asymmetric Fermi Gases at Unitarity
Authors: Aurel Bulgac and Michael McNeil Forbes
Categories: cond-mat.supr-con hep-ph nucl-th
Comments: 10 pages and 7 figures. (Minor changes to correspond with published
version.)
Report-no: NT_at_UW-06-12
Journal-ref: Phys. Rev. A 75, 031605(R), (2007)
DOI: 10.1103/PhysRevA.75.031605
\\ ( http://arxiv.org/abs/cond-mat/0606043 , 560kb)
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\\
arXiv:cond-mat/0611379
replaced with revised version Mon, 4 Jun 2007 12:51:08 GMT (35kb)

Title: Predicting spinor condensate dynamics from simple principles
Authors: M. Moreno-Cardoner, J. Mur-Petit, M. Guilleumas, A. Polls, A. Sanpera,
and M. Lewenstein
Categories: cond-mat.mes-hall
Comments: 4 pages, 2 figures. Version accepted for publication in Phys. Rev.
Letters
\\ ( http://arxiv.org/abs/cond-mat/0611379 , 35kb)
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\\
arXiv:physics/0702119
replaced with revised version Mon, 4 Jun 2007 09:54:57 GMT (670kb)

Title: Trapping of Rb atoms by ac electric fields
Authors: Sophie Schlunk, Adela Marian, Peter Geng, Allard P. Mosk, Gerard
Meijer, and Wieland Schoellkopf
Categories: physics.atom-ph
Journal-ref: Phys. Rev. Lett. 98 223002 (2007)
DOI: 10.1103/PhysRevLett.98.223002
\\ ( http://arxiv.org/abs/physics/0702119 , 670kb)
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\\
arXiv:quant-ph/0701172
replaced with revised version Wed, 6 Jun 2007 16:21:05 GMT (64kb)

Title: Initializing a Quantum Register from Mott Insulator States in Optical
Lattices
Authors: Chuanwei Zhang, V.W. Scarola, and S. Das Sarma
Categories: quant-ph cond-mat.other
Journal-ref: Phys. Rev. A 75, 060301(R) (2007)
DOI: 10.1103/PhysRevA.75.060301
\\ ( http://arxiv.org/abs/quant-ph/0701172 , 64kb)
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\\
arXiv:0704.2299
replaced with revised version Wed, 6 Jun 2007 13:43:43 GMT (425kb)

Title: One-dimensional Rydberg gas in a magneto-electric trap
Authors: Michael Mayle, Bernd Hezel, Igor Lesanovsky and Peter Schmelcher
Categories: physics.atom-ph
\\ ( http://arxiv.org/abs/0704.2299 , 425kb)
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\\
arXiv:physics/0512017
replaced with revised version Thu, 7 Jun 2007 00:38:41 GMT (471kb)

Title: Dynamically controlled toroidal and ring-shaped magnetic traps
Authors: T. Fernholz, R. Gerritsma, P. Krueger, R. J. C. Spreeuw
Categories: physics.atom-ph
Comments: 6 pages, 4 figures. Paragraphs on gravity compensation and expected
Journal-ref: Phys. Rev. A 75, 063406 (2007)
DOI: 10.1103/PhysRevA.75.063406
\\ ( http://arxiv.org/abs/physics/0512017 , 471kb)
------------------------------------------------------------------------------

Next week I'm back home, time will tell whether that means I'll be quicker,
experience suggests perhaps not.

Matt.

--
=========================================================================
Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email: mdavis_at_physics.uq.edu.au
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Australia.                    http://www.physics.uq.edu.au/people/mdavis/
=========================================================================
Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org
http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/
=========================================================================
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views of the sender and not the views of the University of Queensland
=========================================================================

Received on Thu Jun 14 2007 - 21:38:43 EST

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