From: Matthew Davis <mdavis_at_physics.uq.edu.au>

Date: Thu, 14 Jun 2007 21:38:43 +1000 (EST)

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

Comments: 4+ pages, 3 figures

\\

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

Comments: 4 pages, 3 figures

\\

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

Comments: 4 pages, 4 figures

\\

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

Comments: 12 pages, 5 figures

\\

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

Comments: 4 pages, 3 figures

\\

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

Comments: 5 pages, 1 figure

\\

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

Comments: 5 pages, 1 figure

\\

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

Comments: 4 pages, 4 figures

\\

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

Authors: Ali Mohammad Nassimi

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

Comments: 15 pages, 8 figures

\\

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

Comments: 4 pages, 3 figures

\\

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

Comments: 4 pages, 5 figures

\\

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

bound-states made of N fermions.

\\ ( 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

Comments: 5 pages

\\

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

Comments: 18 pages, 12 figures

\\

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

Comments: 5 pages, 5 figures

\\

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

Comments: 4 pages

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

Comments: 6 pages, 3 figures

\\

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

Comments: 4 pages, 4 figures

\\

We demonstrate an efficient scheme for continuous trap loading based upon

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

Comments: 11 pages, 12 figures

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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

Comments: 16pages, 4figures

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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)

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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

Comments: 4 pages, 3 figures

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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

Comments: 4 pages, 3 figures

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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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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

Comments: 4 pages, 4 figures; updated version, added journal reference

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

Comments: 5 pages, 3 figures

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

Comments: 5 pages, 2 figures

\\ ( 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

trap lifetimes added

Journal-ref: Phys. Rev. A 75, 063406 (2007)

DOI: 10.1103/PhysRevA.75.063406

\\ ( http://arxiv.org/abs/physics/0512017 , 471kb)

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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/ ========================================================================= 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 Jun 14 2007 - 21:38:43 EST

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