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

Date: Thu, 09 Oct 2008 17:17:10 +1000

Date: Thu, 09 Oct 2008 17:17:10 +1000

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

Hi all,

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

preprints and 21 replacements this week.

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arXiv:0809.3239

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

Title: Discerning Incompressible and Compressible Phases of Cold Atoms in

Optical Lattices

Authors: V.W. Scarola, L. Pollet, J. Oitmaa, M. Troyer

Categories: cond-mat.other

\\

Experiments with cold atoms trapped in optical lattices offer the potential

to realize a variety of novel phases but suffer from severe spatial

inhomogeneity that can obscure signatures of new phases of matter and phase

boundaries. We use a high temperature series expansion to show that

compressibility in the core of a trapped Fermi-Hubbard system is related to

measurements of changes in double occupancy. This {\em core compressibility}

filters out edge effects, offering a direct probe of compressibility

independent of inhomogeneity. A comparison with experiments is made.

\\ ( http://arxiv.org/abs/0809.3239 , 29kb)

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arXiv:0809.3426

Date: Fri, 19 Sep 2008 17:30:08 GMT (175kb)

Title: Superfluid and Fermi liquid phases of Bose-Fermi mixtures in optical

lattices

Authors: Kaushik Mitra, C. J. Williams and C. A. R. S\'a de Melo

Categories: cond-mat.other

Comments: 4 pages, 2 figures

\\

We describe interacting mixtures of ultracold bosonic and fermionic atoms in

harmonically confined optical lattices. For a suitable choice of parameters we

study the emergence of superfluid and Fermi liquid (non-insulating) regions out

of Bose-Mott and Fermi-band insulators, due to finite Boson and Fermion

hopping. We obtain the shell structure for the system and show that angular

momentum can be transferred to the non-insulating regions from

Laguerre-Gaussian beams, which combined with Bragg spectroscopy can reveal all

superfluid and Fermi liquid shells.

\\ ( http://arxiv.org/abs/0809.3426 , 175kb)

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arXiv:0809.3308

Date: Fri, 19 Sep 2008 06:43:27 GMT (42kb,D)

Title: Heisenberg-limited phase estimation without entanglement or adaptive

measurements

Authors: B. L. Higgins, D. W. Berry, S. D. Bartlett, M. W. Mitchell, H. M.

Wiseman and G. J. Pryde

Categories: quant-ph

Comments: 5 pages, 2 figures

\\

We derive, and experimentally demonstrate, a scheme for Heisenberg-limited

phase estimation that requires neither adaptive measurements nor multiphoton

entangled states. Like a recently introduced adaptive technique [Higgins et

al., Nature 450, 393 (2007)], it employs single photons and multiple

applications of the phase shift. By not requiring adaptive measurements, but

rather using a predetermined measurement sequence, the present scheme is both

conceptually simpler and significantly easier to implement. Additionally, we

demonstrate a simplified adaptive scheme that also surpasses the standard

quantum limit.

\\ ( http://arxiv.org/abs/0809.3308 , 42kb)

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arXiv:0809.3524

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

Title: Unitary perturbation theory approach to real-time evolution problems

Authors: A. Hackl, S. Kehrein

Categories: cond-mat.str-el

Comments: 23 pages, 6 pages

\\

We discuss a new analytical approach to real-time evolution in quantum

many-body systems. Our approach extends the framework of continuous unitary

transformations such that it amounts to a novel solution method for the

Heisenberg equations of motion for an operator. It is our purpose to illustrate

the accuracy of this approach by studying dissipative quantum systems on all

time scales. In particular, we obtain results for non-equilibrium correlation

functions for general initial conditions. We illustrate our ideas for the

exactly solvable dissipative oscillator, and, as a non-trivial model, for the

dissipative two-state system.

\\ ( http://arxiv.org/abs/0809.3524 , 266kb)

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arXiv:0809.3632

Date: Mon, 22 Sep 2008 06:33:13 GMT (61kb)

Title: Damping in 2D and 3D dilute Bose gases

Authors: Ming-Chiang Chung and Aranya B. Bhattacherjee

Categories: cond-mat.other

Comments: 11 pages, 4 figures

\\

Damping in 2D and 3D dilute gases is investigated using both the

hydrodynamical approach and the Hartree-Fock-Bogoliubov (HFB) approximation .

We found that the both methods are good for the Beliaev damping at zero

temperature and Landau damping at very low temperature, however, at high

temperature, the hydrodynamical approach overestimates the Landau damping and

the HFB gives a better approximation. This result shows that the comparison of

the theoretical calculation using the hydrodynamical approach and the

experimental data for high temperature done by Vincent Liu (PRL {\bf21} 4056

(1997)) is not proper. For two-dimensional systems, we show that the Beliaev

damping rate is proportional to $k^3$ and the Landau damping rate is

proportional to $ T^2$ for low temperature and to $T$ for high temperature. We

also show that the hydrodynamical approach gives the same result for zero

temperature and low temperature as HFB, but overestimates the Landau damping

for high temperature.

\\ ( http://arxiv.org/abs/0809.3632 , 61kb)

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arXiv:0809.3679

Date: Mon, 22 Sep 2008 11:00:09 GMT (680kb,D)

Title: Dissipation induced Tonks-Girardeau gas in an optical lattice

Authors: J. J. Garcia-Ripoll, S. D\"urr, N. Syassen, D. M. Bauer, M. Lettner,

G. Rempe, J. I. Cirac

Categories: cond-mat.other

\\

We present a theoretical investigation of a lattice Tonks-gas that is created

by inelastic, instead of elastic interactions. An analytical calculation shows

that in the limit of strong two-body losses, the dynamics of the system is

effectively that of a Tonks gas. We also derive an analytic expression for the

effective loss rate. We find good agreement between these analytical results

and results from a rigorous numerical calculation. The Tonks character of the

gas is visible both in a reduced effective loss rate and in the momentum

distribution of the gas.

\\ ( http://arxiv.org/abs/0809.3679 , 680kb)

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arXiv:0809.3680

Date: Mon, 22 Sep 2008 11:09:27 GMT (16kb)

Title: Many-body approach to low-lying collective excitations in a BEC

approaching collapse

Authors: Anindya Biswas and Tapan Kumar Das

Categories: cond-mat.other

Comments: 8 pages, 2 figures

\\

An approximate many-body theory incorporating two-body correlations has been

employed to calculate low-lying collective multipole frequencies in a

Bose-Einstein condensate containing $A$ bosons, for different values of the

interaction parameter $\lambda=\frac{Aa_{s}}{a_{ho}}$. Significant difference

from the variational estimate of the Gross-Pitaevskii equation has been found

near the collapse region. This is attributed to two-body correlations and

finite range attraction of the realistic interatomic interaction.

\\ ( http://arxiv.org/abs/0809.3680 , 16kb)

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arXiv:0809.3696

Date: Mon, 22 Sep 2008 12:29:35 GMT (60kb)

Title: Lieb-Liniger Model of a Dissipation-Induced Tonks-Girardeau Gas

Authors: S. D\"urr, J. J. Garcia-Ripoll, N. Syassen, D. M. Bauer, M. Lettner,

J. I. Cirac, G. Rempe

Categories: cond-mat.other

\\

We show that strong inelastic interactions between bosons in one dimension

create a Tonks-Girardeau gas, much like in the case of elastic interactions. We

derive a Markovian master equation that describes the loss caused by the

inelastic collisions. This yields a loss rate equation and a dissipative

Lieb-Liniger model. We obtain an analytic expression for the pair correlation

function in the limit of strong dissipation. Numerical calculations show how a

diverging dissipation strength leads to a vanishing of the actual loss rate and

renders an additional elastic part of the interaction irrelevant.

\\ ( http://arxiv.org/abs/0809.3696 , 60kb)

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arXiv:0809.3739

Date: Mon, 22 Sep 2008 16:34:26 GMT (80kb)

Title: Any order imaginary time propagation method for solving the Schrodinger

equation

Authors: Siu A. Chin, S. Janecek and E. Krotscheck

Categories: cond-mat.mtrl-sci cond-mat.str-el

Comments: 8 pages, 3 figures

\\

The eigenvalue-function pair of the 3D Schr\"odinger equation can be

efficiently computed by use of high order, imaginary time propagators. Due to

the diffusion character of the kinetic energy operator in imaginary time,

algorithms developed so far are at most fourth-order. In this work, we show

that for a grid based algorithm, imaginary time propagation of any even order

can be devised on the basis of multi-product splitting. The effectiveness of

these algorithms, up to the 12$^{\rm th}$ order, is demonstrated by computing

all 120 eigenstates of a model C$_{60}$ molecule to very high precisions. The

algorithms are particularly useful when implemented on parallel computer

architectures.

\\ ( http://arxiv.org/abs/0809.3739 , 80kb)

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arXiv:0809.3514

Date: Sat, 20 Sep 2008 16:12:43 GMT (293kb)

Title: Aspects of quantum phase transitions

Authors: M. K. G. Kruse, H. G. Millerr, A. Plastino, A. R. Plastino

Categories: quant-ph cond-mat.stat-mech

\\

A unified description of i) classical phase transitions and their remnants in

finite systems and ii) quantum phase transitions is here presented. The ensuing

discussion relies on the interplay between, on the one hand, the thermodynamic

concepts of temperature and specific heat and on the other, the quantal ones of

coupling strengths in the Hamiltonian. Our considerations are illustrated by

recourse to an exactly solvable model of Plastino and Moszkowski [Il Nuovo

Cimento {\bf 47}, 470 (1978)].

\\ ( http://arxiv.org/abs/0809.3514 , 293kb)

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arXiv:0809.3779

Date: Mon, 22 Sep 2008 19:39:06 GMT (289kb)

Title: Efimov Trimer Formation via Ultracold Four-body Recombination

Authors: Yujun Wang (Department of Physics, Kansas State University) and B. D.

Esry (Department of Physics, Kansas State University)

Categories: quant-ph

Comments: 5 pages, 3 figures

\\

We discuss the collisional formation of Efimov trimers via ultracold

four-body recombination. In particular, we consider the reaction A+A+A+B->A3+B

with A and B ultracold atoms. We obtain expressions for the four-body

recombination rate and show that it reflects the three-body Efimov physics

either as a function of collision energy or as a function of the two-body

s-wave scattering length between A atoms. In addition, we briefly discuss

issues important for experimentally observing this interesting and relatively

unexplored process.

\\ ( http://arxiv.org/abs/0809.3779 , 289kb)

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arXiv:0809.3842

Date: Tue, 23 Sep 2008 02:52:16 GMT (379kb)

Title: Directional spatial structure of dissociated elongated molecular

condensates

Authors: Magnus \"Ogren, C.M. Savage, K.V. Kheruntsyan

Categories: cond-mat.other

\\

Ultra-cold clouds of dimeric molecules can dissociate into quantum

mechanically correlated constituent atoms that are either bosons or fermions.

We theoretically model the dissociation of cigar shaped molecular condensates,

for which this difference manifests as complementary geometric structures of

the dissociated atoms. For atomic bosons beams form along the long axis of the

molecular condensate. For atomic fermions beams form along the short axis. This

directional beaming simplifies the measurement of correlations between the

atoms through relative number squeezing.

\\ ( http://arxiv.org/abs/0809.3842 , 379kb)

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arXiv:0809.3920

Date: Tue, 23 Sep 2008 14:01:07 GMT (2729kb)

Title: Ultracold Feshbach Molecules

Authors: Francesca Ferlaino, Steven Knoop, and Rudolf Grimm

Categories: cond-mat.other cond-mat.stat-mech

Comments: Chapter of the book: "Cold molecules: Creation and applications",

edited by R. V. Krems, B. Friedrich and W. C. Stwalley, and published by

Taylor & Francis (March 2009)

\\

In this Chapter, we give an introduction into experiments with Feshbach

molecules and their applications. In particular, we discuss the various

creation and detection methods, and the internal-state manipulation of such

molecules. We highlight two topics, namely Feshbach molecules in the halo

regime and the application of Feshbach molecule to achieve ultracold gases of

molecules in the rovibrational ground state. Our illustrative examples are

mainly based on work performed at Innsbruck University.

\\ ( http://arxiv.org/abs/0809.3920 , 2729kb)

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arXiv:0809.3975

Date: Tue, 23 Sep 2008 17:44:58 GMT (67kb)

Title: Van-der-Waals potentials of paramagnetic atoms

Authors: Hassan Safari, Dirk-Gunnar Welsch, Stefan Yoshi Buhmann, Stefan Scheel

Categories: quant-ph

Comments: 18 pages, 3 figures, 1 table

\\

We study single- and two-atom van der Waals interactions of ground-state

atoms which are both polarizable and paramagnetizable in the presence of

magneto-electric bodies within the framework of macroscopic quantum

electrodynamics. Starting from an interaction Hamiltonian that includes

particle spins, we use leading-order perturbation theory for the van der Waals

potentials expressed in terms of the polarizability and magnetizability of the

atom(s). To allow for atoms embedded in media, we also include local-field

corrections via the real-cavity model. The general theory is applied to the

potential of a single atom near a half space and that of two atoms embedded in

a bulk medium or placed near a sphere, respectively.

\\ ( http://arxiv.org/abs/0809.3975 , 67kb)

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arXiv:0809.4114

Date: Wed, 24 Sep 2008 07:38:32 GMT (53kb)

Title: Spatially-modulated Superfluid States in Fermionic Optical Ladder

Systems with Repulsive Interactions

Authors: Yusuke Fujihara, Akihisa Koga, Norio Kawakami

Categories: cond-mat.stat-mech cond-mat.supr-con

Comments: 8 pages, 5 figures

\\

We investigate two-component ultracold fermionic atoms with repulsive

interactions trapped in an optical lattice with a ladder structure. By applying

the Bogoliubov-de Gennes equations to an effective t-J model in the strong

correlation limit, we discuss how the spatially-modulated spin-singlet pairs

with d-wave like symmetry are formed in the systems with trapping potentials.

Furthermore, a close examination of the condensation energy as well as the

local average of potential, kinetic and exchange energies by means of the

variational Monte Carlo method elucidates that local particle correlations

enhance the stability of the superfluid state via substantial energy gain due

to singlet pairing in the high particle density region.

\\ ( http://arxiv.org/abs/0809.4114 , 53kb)

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arXiv:0809.4189

Date: Wed, 24 Sep 2008 13:51:38 GMT (20kb)

Title: BEC-BCS crossover in a Bose gas

Authors: Arnaud Koetsier, P. Massignan, R. A. Duine and H. T. C. Stoof

Categories: cond-mat.other

Comments: 4 pages, 3 figures, RevTeX

Report-no: ITP-UU-08/56

\\

We calculate the critical temperature for pair condensation in a gas of

bosonic atoms across a Feshbach resonance. Using the Nozieres-Schmitt-Rink

formalism, we show how medium effects at negative scattering lengths give rise

to pairs which are reminiscent of the ones responsible for fermionic

superfluidity. Furthermore, we find that these preformed pairs lead to a strong

suppression of the critical temperature for superfluidity. We also find that

the compressibility of the gas in its normal phase is positive, and therefore

confirm its mechanical stability throughout the entire crossover region.

Finally, we discuss prospects of observing this crossover in a gas of ultracold

133Cs atoms where recent measurements indicate that this bosonic gas may be

sufficiently long-lived to explore the crossover experimentally.

\\ ( http://arxiv.org/abs/0809.4189 , 20kb)

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arXiv:0809.4226

Date: Wed, 24 Sep 2008 16:25:15 GMT (670kb)

Title: Bragg spectroscopy and Ramsey interferometry with an ultracold Fermi gas

Authors: B. Deh, C. Marzok, S. Slama, C. Zimmermann, and Ph. W. Courteille

Categories: cond-mat.other

Comments: 19 pages, 10 figures

\\

We report on the observation of Bragg scattering of an ultracold Fermi gas of

6Li atoms at a dynamic optical potential. The momentum states produced in this

way oscillate in the trap for time scales on the order of seconds, nearly

unperturbed by collisions, which are absent for ultracold fermions due to the

Pauli principle. In contrast, interactions in a mixture with 87Rb atoms lead to

rapid damping. The coherence of these states is demonstrated by Ramsey-type

matter wave interferometry. The signal is improved using an echo pulse

sequence, allowing us to observe coherence times longer than 100 mus. Finally

we use Bragg spectroscopy to measure the in-situ momentum distribution of the

6Li cloud. Signatures for the degeneracy of the Fermi gas can be observed

directly from the momentum distribution of the atoms inside the trap.

\\ ( http://arxiv.org/abs/0809.4226 , 670kb)

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arXiv:0809.4294

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

Title: Collapse times of dipolar Bose-Einstein condensates

Authors: C. Ticknor, N.G. Parker, A. Melatos, S.L. Cornish, D.H.J. O'Dell and

A.M Martin

Categories: cond-mat.other

Comments: 5 pages with 3 figures

\\

We investigate the time taken for global collapse by a dipolar Bose-Einstein

condensate. Two semi-analytical approaches and exact numerical integration of

the mean-field dynamics are considered. The semi-analytical approaches are

based on a Gaussian ansatz and a Thomas-Fermi solution for the shape of the

condensate. The regimes of validity for these two approaches are determined,

and their predictions for the collapse time revealed and compared with

numerical simulations. The dipolar interactions introduce anisotropy into the

collapse dynamics and predominantly lead to collapse in the plane perpendicular

to the axis of polarization.

\\ ( http://arxiv.org/abs/0809.4294 , 545kb)

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arXiv:0809.4307

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

Title: Non-Abelian Josephson effect between two spinor Bose-Einstein

condensates in double optical traps

Authors: Ran Qi, Xiao-Lu Yu, Z. B. Li and W. M. Liu

Categories: cond-mat.other

Comments: 5 pages, 3 figures

\\

We investigate the non-Abelian Josephson effect in spinor Bose-Einstein

condensates with double optical traps. We propose, for the first time, a real

physical system which contains non-Abelian Josephson effects. The collective

modes of this weak coupling system have very different density and spin

tunneling characters comparing to the Abelian case. We calculate the

frequencies of the pseudo Goldstone modes in different phases between two traps

respectively, which are a crucial feature of the non-Abelian Josephson effects.

We also give an experimental protocol to observe this novel effect in future

experiments.

\\ ( http://arxiv.org/abs/0809.4307 , 69kb)

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arXiv:0809.4356

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

Title: Vortex solitons in dipolar Bose-Einstein Condensates

Authors: I. Tikhonenkov, B. A. Malomed, A. Vardi

Categories: cond-mat.other

Comments: 6 pages, 6 figures

\\

We predict solitary vortices in quasi-planar condensates of dipolar atoms,

polarized parallel to the confinement direction, with the effective sign of the

dipole-dipole interaction inverted by means of a rapidly rotating field. Energy

minima corresponding to vortex solitons with topological charges ${% \ell}=1$

and 2 are predicted for moderately strong dipole-dipole interaction, using an

axisymmetric Gaussian ansatz. The stability of the solitons with $\ell =1$ is

confirmed by full 3D simulations, whereas their counterparts with $\ell =2$ are

found to be unstable against splitting into a set of four fragments

(quadrupole).

\\ ( http://arxiv.org/abs/0809.4356 , 912kb)

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arXiv:0809.4397

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

Title: Recent progress in open quantum systems: Non-Gaussian noise and

decoherence in fermionic systems

Authors: Clemens Neuenhahn, B. Kubala, B. Abel, Florian Marquardt

Categories: cond-mat.mes-hall

Comments: Proceedings of Ustron 2008 conference, 6 pages, 3 figures

\\

We review our recent contributions to two topics that have become of interest

in the field of open, dissipative quantum systems: non-Gaussian noise and

decoherence in fermionic systems. Decoherence by non-Gaussian noise, i.e. by an

environment that cannot be approximated as a bath of harmonic oscillators, is

important in nanostructures (e.g. qubits) where there might be strong coupling

to a small number of fluctuators. We first revisit the pedagogical example of

dephasing by classical telegraph noise. Then we address two models where the

quantum nature of the noise becomes essential: "quantum telegraph noise" and

dephasing by electronic shot noise. In fermionic systems, many-body aspects and

the Pauli principle have to be taken care of when describing the loss of phase

coherence. This is relevant in electronic quantum transport through metallic

and semiconducting structures. Specifically, we recount our recent results

regarding dephasing in a chiral interacting electron liquid, as it is realized

in the electronic Mach-Zehnder interferometer. This model can be solved

employing the technique of bosonization as well as a physically transparent

semiclassical method.

\\ ( http://arxiv.org/abs/0809.4397 , 1646kb)

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arXiv:0809.4400

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

Title: Finite temperature vortex dynamics in Bose Einstein condensates

Authors: B. Jackson, N.P. Proukakis, C.F. Barenghi and E. Zaremba

Categories: cond-mat.stat-mech

Comments: 16 pages, 10 figures, submitted

\\

We study the decay of vortices in Bose-Einstein condensates at finite

temperatures by means of the Zaremba Nikuni Griffin formalism, in which the

condensate is modelled by a Gross Pitaevskiiequation, which is coupled to a

Boltzmann kinetic equation for the thermal cloud. At finite temperature, an

off-centred vortex in a harmonically trapped pancake shaped condensate decays

by spiralling out towards the edge of the condensate. This decay, which depends

heavily on temperature and atomic collisions, agrees with that predicted by the

Hall Vinen phenomenological model of friction force, which is used to describe

quantised vorticity in superfluid systems. Our result thus clarifies the

microscopic origin of the friction and provides an ab initio determination of

its value.

\\ ( http://arxiv.org/abs/0809.4400 , 1447kb)

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arXiv:0809.4419

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

Title: Fermionization of a strongly interacting Bose-Fermi mixture in a

one-dimensional harmonic trap

Authors: Bess Yiyuan Fang (University of Singapore), Patrizia Vignolo (INLN,

Nice, France), Christian Miniatura (INLN, Nice, France), Anna Minguzzi

(LPMMC, Grenoble, France)

Categories: cond-mat.other

Comments: 8 pages, 7 figures

\\

We consider a strongly interacting one-dimensional (1D) Bose-Fermi mixture

confined in a harmonic trap. It consists of a Tonks-Girardeau (TG) gas (1D Bose

gas with repulsive hard-core interactions) and of a non-interacting Fermi gas

(1D spin-aligned Fermi gas), both species interacting through hard-core

repulsive interactions. Using a generalized Bose-Fermi mapping, we determine

the exact particle density profiles, momentum distributions and behaviour of

the mixture under 1D expansion when opening the trap. In real space, bosons and

fermions do not display any phase separation: the respective density profiles

extend over the same region and they both present a number of peaks equal to

the total number of particles in the trap. In momentum space the bosonic

component has the typical narrow TG profile, while the fermionic component

shows a broad distribution with fermionic oscillations at small momenta. Due to

the large boson-fermion repulsive interactions, both the bosonic and the

fermionic momentum distributions decay as $C p^{-4}$ at large momenta, like in

the case of a pure bosonic TG gas. The coefficient $C$ is related to the

two-body density matrix and to the bosonic concentration in the mixture. When

opening the trap, both momentum distributions "fermionize" under expansion and

turn into that of a Fermi gas with a particle number equal to the total number

of particles in the mixture.

\\ ( http://arxiv.org/abs/0809.4419 , 456kb)

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arXiv:0809.4368

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

Title: Quantum computing with trapped ions

Authors: H. Haeffner, C.F. Roos, R. Blatt

Categories: quant-ph

Comments: Review article, accepted for publication in Physics Reports, 99pages,

38 Figures, ~2 MByte

\\

Quantum computers hold the promise to solve certain computational task much

more efficiently than classical computers. We review the recent experimental

advancements towards a quantum computer with trapped ions. In particular,

various implementations of qubits, quantum gates and some key experiments are

discussed. Furthermore, we review some implementations of quantum algorithms

such as a deterministic teleportation of quantum information and an error

correction scheme.

\\ ( http://arxiv.org/abs/0809.4368 , 1468kb)

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arXiv:0809.4373

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

Title: Quantum resonances in the delta-kicked harmonic oscillator

Authors: T. P. Billam and S. A. Gardiner

Categories: quant-ph

Comments: 4 pages, 3 figures

\\

We investigate characteristic quantum resonances occurring in the

delta-kicked harmonic oscillator theoretically. We develop a physical

explanation for the quantum resonances based on symmetries shared between the

classical phase space and the quantum-mechanical time evolution operator. We

show that the primary quantum resonances correspond to a situation where action

of the applied kicks is entirely commutative, and that higher order resonances

correspond to a partial commutativity. We suggest experimental conditions in an

atom-optical context under which the primary quantum resonances could be

directly observed.

\\ ( http://arxiv.org/abs/0809.4373 , 904kb)

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arXiv:0809.4388

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

Title: Freezing a Coherent Field Growth in a Cavity by Quantum Zeno Effect

Authors: Julien Bernu (LKB - Lhomond), Samuel Del\'eglise (LKB - Lhomond),

Cl\'ement Sayrin (LKB - Lhomond), Stefan Kuhr, Igor Dotsenko (LKB - Lhomond,

CDF), Michel Brune (LKB - Lhomond), Jean-Michel Raimond (LKB - Lhomond),

Serge Haroche (LKB - Lhomond)

Categories: quant-ph

\\

We have frozen the coherent evolution of a field in a cavity by repeated

measurements of its photon number. We use circular Rydberg atoms dispersively

coupled to the cavity mode for an absorption-free photon counting. These

measurements inhibit the growth of a Field injected in the cavity by a

classical source. This manifestation of the Quantum Zeno effect illustrates the

back action of the photon number determination onto the Field phase. The

residual growth of the Field can be seen as a random walk of its amplitude in

the two-dimensional phase space. This experiment sheds light onto the

measurement process and opens perspectives for active quantum feedback.

\\ ( http://arxiv.org/abs/0809.4388 , 1064kb)

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arXiv:0809.4466

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

Title: A term-rewriting system for computer quantum algebra

Authors: J. J. Hudson

Categories: quant-ph

Comments: 16 pages, 1 table

\\

Existing computer algebra packages do not fully support quantum mechanics

calculations in Dirac's notation. I present the foundation for building such

support: a mathematical system for the symbolic manipulation of expressions

used in the invariant formalism of quantum mechanics. I first describe the

essential mathematical features of the Hilbert-space invariant formalism. This

is followed by a formal characterisation of all possible algebraic expressions

in this formalism. This characterisation is provided in the form of a set of

terms. Rewrite rules over this set of terms are then developed that correspond

to allowed manipulations of the algebraic expressions. This approach is

contrasted with current attempts to build invariant quantum mechanics

calculations into computer algebra systems.

\\ ( http://arxiv.org/abs/0809.4466 , 16kb)

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and something I couldn't resist including... who could have possibly thought

this might be a risk????

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arXiv:0809.4004 (*cross-listing*)

Date: Tue, 23 Sep 2008 20:00:51 GMT (6kb)

Title: There is no explosion risk associated with superfluid Helium in the LHC

cooling system

Authors: Malcolm Fairbairn and Bob McElrath

Categories: physics.pop-ph cond-mat.other hep-ex hep-ph physics.atom-ph

physics.ins-det

Comments: 6 pages

\\

We evaluate speculation about the possibility of a dangerous release of

energy within the liquid Helium of the Large Hadron Collider (LHC) cryogenic

system due to the occurrence of a "Bose-Nova". Bose-Novae are radial bursts of

rapidly moving atoms which can occur when a Bose-Einstein Condensate (BEC)

undergoes a collapse due the interatomic potential being deliberately made

attractive using a magnetic field close to the Feshbach resonance. Liquid 4He

has a monatomic structure with s-wave electrons, zero nuclear spin, no

hyperfine splitting, and as a consequence no Feshbach resonance which would

allow one to change its normally repulsive interactions to be attractive.

Because of this, a Bose-Nova style collapse of 4He is impossible. Additional

speculations concerning cold fusion during these events are easily dismissed

using the usual arguments about the Coulomb barrier at low temperatures, and

are not needed to explain the Bose-Einstein condensate Bose-Nova phenomenon. We

conclude that that there is no physics whatsoever which suggests that Helium

could undergo any kind of unforeseen catastrophic explosion.

\\ ( http://arxiv.org/abs/0809.4004 , 6kb)

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The replacements:

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arXiv:cond-mat/0701739

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

Title: Accurate determination of the superfluid-insulator transition in the

one-dimensional Bose-Hubbard model

Authors: Jakub Zakrzewski and Dominique Delande

Categories: cond-mat.stat-mech cond-mat.other

Comments: revised version, modified fig.1, a reference added, 5pp. 3figs

\\ ( http://arxiv.org/abs/cond-mat/0701739 , 39kb)

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\\

arXiv:0803.2187

replaced with revised version Fri, 19 Sep 2008 13:17:46 GMT (113kb)

Title: Splitting of doubly quantized vortices in dilute Bose-Einstein

condensates

Authors: K. Gawryluk, T. Karpiuk, M. Brewczyk, K. Rzazewski

Categories: cond-mat.other

Comments: 1 page, 1 figure

Journal-ref: Phys. Rev. A 78, 025603 (2008)

DOI: 10.1103/PhysRevA.78.025603

\\ ( http://arxiv.org/abs/0803.2187 , 113kb)

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\\

arXiv:0805.3226

replaced with revised version Fri, 19 Sep 2008 19:41:57 GMT (377kb)

Title: Thermodynamics of a trapped unitary Fermi gas

Authors: R. Haussmann and W. Zwerger

Categories: cond-mat.stat-mech

Comments: 10 pages, 5 figures

Report-no: KN-08-05

\\ ( http://arxiv.org/abs/0805.3226 , 377kb)

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\\

arXiv:0806.4961

replaced with revised version Fri, 19 Sep 2008 12:12:24 GMT (120kb)

Title: Spectral signatures of the Fulde-Ferrell-Larkin-Ovchinnikov order

parameter in one-dimensional optical lattices

Authors: M. Reza Bakhtiari, M.J. Leskinen, P. Torma

Categories: cond-mat.other

Comments: published version

Journal-ref: Phys.Rev.Lett. 101, 120404 (2008)

DOI: 10.1103/PhysRevLett.101.120404

\\ ( http://arxiv.org/abs/0806.4961 , 120kb)

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\\

arXiv:0807.2194

replaced with revised version Fri, 19 Sep 2008 18:22:53 GMT (42kb)

Title: Internal structure of a quantum soliton and classical excitations due to

trap opening

Authors: Yvan Castin (LKB - Lhomond)

Categories: cond-mat.other

Comments: 12 pages; 2 figures added ; a few typos corrected

\\ ( http://arxiv.org/abs/0807.2194 , 42kb)

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\\

arXiv:0809.1818 (*cross-listing*)

replaced with revised version Fri, 19 Sep 2008 15:10:46 GMT (26kb)

Title: Transition to the giant vortex state for a Bose-Einstein condensate in a

rotating anharmonic trap

Authors: Nicolas Rougerie

Categories: math-ph cond-mat.other math.MP

Comments: 40 pages

MSC-class: 35Q55,47J30,76M23

\\ ( http://arxiv.org/abs/0809.1818 , 26kb)

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\\

arXiv:0809.0061

replaced with revised version Fri, 19 Sep 2008 13:21:38 GMT (150kb)

Title: Ultracold Molecules in the Ro-Vibrational Triplet Ground State

Authors: F. Lang, K. Winkler, C. Strauss, R. Grimm, J. Hecker Denschlag

Categories: quant-ph

Comments: 4 pages, 3 figures. Phys. Rev. Lett. accepted

\\ ( http://arxiv.org/abs/0809.0061 , 150kb)

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\\

arXiv:0807.3272

replaced with revised version Fri, 19 Sep 2008 08:06:14 GMT (246kb)

Title: Formation of ultracold polar molecules in the rovibrational ground state

Authors: J. Deiglmayr, A. Grochola, M. Repp, K. M\"ortlbauer, C. Gl\"uck, J.

Lange, O. Dulieu, R. Wester, and M. Weidem\"uller

Categories: quant-ph physics.atom-ph

\\ ( http://arxiv.org/abs/0807.3272 , 246kb)

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\\

arXiv:0804.1672

replaced with revised version Mon, 22 Sep 2008 05:02:25 GMT (51kb)

Title: Criterion for Bose-Einstein condensation in traps and self-bound systems

Authors: T. Yamada, Y. Funaki, H. Horiuchi, G. Roepke, P. Schuck, and A.

Tohsaki

Categories: cond-mat.other nucl-th

Comments: Shortened to Brief report

Journal-ref: Phys. Rev. A 78, 035603 (2008)

\\ ( http://arxiv.org/abs/0804.1672 , 51kb)

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\\

arXiv:0804.3977

replaced with revised version Mon, 22 Sep 2008 08:01:05 GMT (286kb)

Title: Incommensurate superfluidity of bosons in a double-well optical lattice

Authors: Vladimir M. Stojanovic, Congjun Wu, W. Vincent Liu, S. Das Sarma

Categories: cond-mat.other quant-ph

Comments: 4 pages, 5 figures;

Journal-ref: Phys. Rev. Lett. 101, 125301 (2008)

DOI: 10.1103/PhysRevLett.101.125301

\\ ( http://arxiv.org/abs/0804.3977 , 286kb)

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\\

arXiv:0807.0790

replaced with revised version Mon, 22 Sep 2008 16:29:20 GMT (34kb)

Title: Trapping and cooling fermionic atoms into the Mott and N\'eel states

Authors: L. De Leo, C. Kollath, A. Georges, M. Ferrero, O. Parcollet

Categories: cond-mat.str-el

Comments: New version submitted to PRL on September 12. More quantitative

discussion of D vs. N, in connection with local compressibility

\\ ( http://arxiv.org/abs/0807.0790 , 34kb)

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arXiv:0807.2418

replaced with revised version Mon, 22 Sep 2008 14:21:09 GMT (258kb)

Title: Damped bounces of an isolated perfect quantum gas

Authors: S. Camalet

Categories: cond-mat.mes-hall

\\ ( http://arxiv.org/abs/0807.2418 , 258kb)

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\\

arXiv:0805.0488

replaced with revised version Tue, 23 Sep 2008 05:13:35 GMT (914kb,D)

Title: Physical replicas and the Bose-glass in cold atomic gases

Authors: S. Morrison, A. Kantian, A. J. Daley, H.G. Katzgraber, M. Lewenstein,

H. P. B\"uchler, and P. Zoller

Categories: cond-mat.other cond-mat.dis-nn

Comments: 17 pages, 6 figures, updated and added several references, other

minor changes and corrections

Journal-ref: New J. Phys. 10, 073032 (2008)

DOI: 10.1088/1367-2630/10/7/073032

\\ ( http://arxiv.org/abs/0805.0488 , 914kb)

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arXiv:0805.1256

replaced with revised version Tue, 23 Sep 2008 04:38:06 GMT (852kb,D)

Title: Dissipation-driven quantum phase transitions in collective spin systems

Authors: S. Morrison and A. S. Parkins

Categories: quant-ph cond-mat.other

Comments: 12 pages, 16 figures, removed section on homodyne spectra

Journal-ref: J. Phys. B 41, 195502 (2008)

DOI: 10.1088/0953-4075/41/19/195502

\\ ( http://arxiv.org/abs/0805.1256 , 852kb)

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arXiv:0806.3894

replaced with revised version Tue, 23 Sep 2008 16:03:56 GMT (644kb,D)

Title: Fractional resonances in the atom-optical delta-kicked accelerator

Authors: M. Saunders, P.L. Halkyard, S.A. Gardiner, and K.J. Challis

Categories: physics.atom-ph nlin.CD

Comments: 18 pages, 8 figures

\\ ( http://arxiv.org/abs/0806.3894 , 644kb)

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arXiv:cond-mat/0508306

replaced with revised version Wed, 24 Sep 2008 06:14:56 GMT (42kb)

Title: Order via Nonlinearity in Randomly Confined Bose Gases

Authors: Robert Graham and Axel Pelster

Categories: cond-mat.dis-nn

Comments: Author Information under

http://www.theo-phys.uni-essen.de/tp/ags/pelster_dir/. International Journal

of Bifurcation and Chaos (in press)

\\ ( http://arxiv.org/abs/cond-mat/0508306 , 42kb)

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arXiv:0804.3280

replaced with revised version Wed, 24 Sep 2008 08:00:25 GMT (67kb)

Title: Interband physics in an ultra-cold Fermi gas in an optical lattice

Authors: J.-P. Martikainen, E. Lundh, and T. Paananen

Categories: cond-mat.stat-mech cond-mat.supr-con

Comments: 5 pages, 2 figures

Report-no: NORDITA-2008-17

Journal-ref: Phys. Rev. A 78, 023607 (2008)

\\ ( http://arxiv.org/abs/0804.3280 , 67kb)

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arXiv:0808.0646

replaced with revised version Wed, 24 Sep 2008 08:02:16 GMT (14kb)

Title: Cooper problem in a lattice

Authors: J.-P. Martikainen

Categories: cond-mat.stat-mech cond-mat.supr-con

Comments: 4 pages, 3 figures

Report-no: NORDITA-2008-32

Journal-ref: Phys. Rev. A 78, 035602 (2008)

\\ ( http://arxiv.org/abs/0808.0646 , 14kb)

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arXiv:0805.3510

replaced with revised version Wed, 24 Sep 2008 08:17:47 GMT (538kb)

Title: Energy distribution and cooling of a single atom in an optical tweezer

Authors: C. Tuchendler, A. M. Lance, A. Browaeys, Y. R. P. Sortais and P.

Grangier

Categories: quant-ph

Comments: 9 pages, 6 figures, published in PRA

Journal-ref: Phys. Rev. A 78, 033425 (2008)

\\ ( http://arxiv.org/abs/0805.3510 , 538kb)

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arXiv:0709.0527

replaced with revised version Thu, 25 Sep 2008 09:55:50 GMT (564kb,D)

Title: Quantum Non-Demolition Detection of Strongly Correlated Systems

Authors: Kai Eckert, Oriol Romero-Isart, Mirta Rodriguez, Maciej Lewenstein,

Eugene S. Polzik and Anna Sanpera

Categories: cond-mat.other quant-ph

Comments: Published version

Journal-ref: Nature Physics 4, 50-54 (2008)

DOI: 10.1038/nphys776

\\ ( http://arxiv.org/abs/0709.0527 , 564kb)

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arXiv:0806.0212

replaced with revised version Thu, 25 Sep 2008 07:20:13 GMT (916kb,D)

Title: Paired atom laser beams created via four-wave mixing

Authors: R. G. Dall, L. J. Byron, A. G. Truscott, G. R. Dennis, M. T. Johnsson,

J. J. Hope

Categories: quant-ph

Comments: 5 pages, 3 figures

\\ ( http://arxiv.org/abs/0806.0212 , 916kb)

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Till next time,

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 Fri Oct 10 2008 - 13:21:20 EST

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