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

Date: Wed, 29 Oct 2008 17:55:04 +1000

Date: Wed, 29 Oct 2008 17:55:04 +1000

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

Hi everyone,

I'm back from Beijing this week, impressed by all the great work that everyone

is doing and slightly anxious I won't ever be able to keep up with it all. I

would like to acknowledge all the people I chatted to that thanked me for this

email service - positive feedback means it is more likely that it will continue

into the future!

This week there were 27 new preprints this week, yet only 3 YY replacements.

------------------------------------------------------------------------------

\\

arXiv:0810.3005

Date: Fri, 17 Oct 2008 12:26:15 GMT (75kb,D)

Title: Quantum criticality and black holes

Authors: Subir Sachdev and Markus Mueller

Categories: cond-mat.str-el hep-th

Comments: 12 pages, 2 figures; Talk at LT25, Amsterdam

\\

Many condensed matter experiments explore the finite temperature dynamics of

systems near quantum critical points. Often, there are no well-defined

quasiparticle excitations, and so quantum kinetic equations do not describe the

transport properties completely. The theory shows that the transport

co-efficients are not proportional to a mean free scattering time (as is the

case in the Boltzmann theory of quasiparticles), but are completely determined

by the absolute temperature and by equilibrium thermodynamic observables.

Recently, explicit solutions of this quantum critical dynamics have become

possible via the AdS/CFT duality discovered in string theory. This shows that

the quantum critical theory provides a holographic description of the quantum

theory of black holes in a negatively curved anti-de Sitter space, and relates

its transport co-efficients to properties of the Hawking radiation from the

black hole. We review how insights from this connection have led to new results

for experimental systems: (i) the vicinity of the superfluid-insulator

transition in the presence of an applied magnetic field, and its possible

application to measurements of the Nernst effect in the cuprates, (ii) the

magnetohydrodynamics of the plasma of Dirac electrons in graphene and the

prediction of a hydrodynamic cyclotron resonance.

\\ ( http://arxiv.org/abs/0810.3005 , 75kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3051

Date: Fri, 17 Oct 2008 02:21:04 GMT (2kb)

Title: Comments on "Thermally induced rotons in two-dimensional dilute Bose

gases" [arXiv:cond-mat/0503523]

Authors: Sang-Hoon Kim

Categories: cond-mat.stat-mech

Comments: 1page

\\

A mistake of the effective interaction between D-dimensional Bose atoms

[arXiv:cond-mat/0503523] that was published by Physical Review B in 2006 is

corrected.

\\ ( http://arxiv.org/abs/0810.3051 , 2kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3061

Date: Fri, 17 Oct 2008 05:52:52 GMT (157kb)

Title: Quantum Nucleation and Macroscopic Quantum Tunneling in Cold-Atom

Boson-Fermion Mixtures

Authors: Dmitry Solenov and Dmitry Mozyrsky

Categories: cond-mat.mes-hall cond-mat.str-el

Comments: 13 pages, 5 figures

\\

Kinetics of phase separation transition in boson-fermion cold atom mixtures

is investigated. We identify the parameters at which the transition is governed

by quantum nucleation mechanism, responsible for the formation of critical

nuclei of a stable phase. We demonstrate that for low fermion-boson mass ratio

the density dependence of quantum nucleation transition rate is experimentally

observable. The crossover to macroscopic quantum tunneling regime is analyzed.

Based on a microscopic description of interacting cold atom boson-fermion

mixtures we derive an effective action for the critical droplet and obtain an

asymptotic expression for the nucleation rate in the vicinity of the phase

transition and near the spinodal instability of the mixed phase. We show that

dissipation due to excitations in fermion subsystem play a dominant role close

to the transition point.

\\ ( http://arxiv.org/abs/0810.3061 , 157kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3088

Date: Fri, 17 Oct 2008 08:39:09 GMT (352kb)

Title: Spacetime analogue of Bose-Einstein condensates: Bogoliubov-de Gennes

formulation

Authors: Yasunari Kurita, Michikazu Kobayashi, Takao Morinari, Makoto Tsubota,

Hideki Ishihara

Categories: cond-mat.other

Comments: 7 pages, 6 figures

Report-no: OCU-PHYS-305, AP-GR-62, YITP-08-77

\\

We construct quantum field theory in an analogue curved spacetime in

Bose-Einstein condensates based on the Bogoliubov-de Gennes equations, by

identifying quantum particles in curved spacetime with Bogoliubov quasiparticle

excitations in Bose-Einstein condensates. Here, we derive a simple formula

relating the two, which can be used to calculate the particle creation spectrum

by solving the time-dependent Bogoliubov-de Gennes equations. Using our

formulation, we numerically investigate particle creation in an analogue

expanding Universe which can be expressed as Bogoliubov quasiparticles in an

expanding Bose-Einstein condensate. We obtain its spectrum, which follows the

thermal Maxwell-Boltzmann distribution, the temperature of which is

experimentally attainable. This is the first direct numerical simulation for

particle creation and its spectrum in analogue curved spacetime by using a

Bose-Einstein condensate system.

\\ ( http://arxiv.org/abs/0810.3088 , 352kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3092

Date: Fri, 17 Oct 2008 08:50:12 GMT (10kb)

Title: Foundation of Statistical Mechanics under experimentally realistic

conditions

Authors: Peter Reimann

Categories: cond-mat.stat-mech

Comments: Accepted in Phys. Rev. Lett

\\

We demonstrate the equilibration of isolated macroscopic quantum systems,

prepared in non-equilibrium mixed states with significant population of many

energy levels, and observed by instruments with a reasonably bound working

range compared to the resolution limit. Both properties are fulfilled under

many, if not all, experimentally realistic conditions. At equilibrium, the

predictions and limitations of Statistical Mechanics are recovered.

\\ ( http://arxiv.org/abs/0810.3092 , 10kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3036

Date: Thu, 16 Oct 2008 22:24:19 GMT (1687kb,D)

Title: Faddeev-Merkuriev integral equations for atomic three-body resonances

Authors: S Keller, A Marotta and Z Papp

Categories: physics.atom-ph

Comments: 17 pages, 5 figures

\\

Three-body resonances in atomic systems are calculated as complex-energy

solutions of Faddeev-type integral equations. The homogeneous Faddeev-Merkuriev

integral equations are solved by approximating the potential terms in a

Coulomb-Sturmian basis. The Coulomb-Sturmian matrix elements of the three-body

Coulomb Green's operator has been calculated as a contour integral of two-body

Coulomb Green's matrices. This approximation casts the integral equation into a

matrix equation and the complex energies are located as the complex zeros of

the Fredholm determinant. We calculated resonances of the e-Ps system at higher

energies and for total angular momentum L=1 with natural and unnatural parity

\\ ( http://arxiv.org/abs/0810.3036 , 1687kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3152

Date: Fri, 17 Oct 2008 13:03:07 GMT (374kb)

Title: Combination of Bloch oscillations with a Ramsey-Bord\'e interferometer :

new determination of the fine structure constant

Authors: Malo Cadoret (LKB - Jussieu), Estefania De Mirandes (LKB - Jussieu),

Pierre Clad\'e (LKB - Jussieu), Sa\"ida Guellati-Kh\'elifa (BNM-INM),

Catherine Schwob (LKB - Jussieu), Fran\c{c}ois Nez (LKB - Jussieu), Lucile

Julien (LKB - Jussieu), Fran\c{c}ois Biraben (LKB - Jussieu)

Categories: physics.atom-ph

\\

We report a new experimental scheme which combines atom interferometry with

Bloch oscillations to provide a new measurement of the ratio

$h/m_{\mathrm{Rb}}$. By using Bloch oscillations, we impart to the atoms up to

1600 recoil momenta and thus we improve the accuracy on the recoil velocity

measurement. The deduced value of $h/m_{\mathrm{Rb}}$ leads to a new

determination of the fine structure constant $\alpha^{-1}=137.035 999 45 (62)$

with a relative uncertainty of $4.6\times 10^{-9}$. The comparison of this

result with the value deduced from the measurement of the electron anomaly

provides the most stringent test of QED.

\\ ( http://arxiv.org/abs/0810.3152 , 374kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3263

Date: Fri, 17 Oct 2008 22:00:19 GMT (246kb)

Title: Dirty Bosons: Twenty Years Later

Authors: Peter B. Weichman

Categories: cond-mat.dis-nn cond-mat.supr-con

Comments: 26 pages, 9 figures, submitted to Modern Physics Letters B (Brief

Reviews)

\\

A concise, somewhat personal, review of the problem of superfluidity and

quantum criticality in regular and disordered interacting Bose systems is

given, concentrating on general features and important symmetries that are

exhibited in different parts of the phase diagram, and that govern the

different possible types of critical behavior. A number of exact results for

various insulating phase boundaries, which may be used to constrain the results

of numerical simulations, can be derived using large rare region type

arguments. The nature of the insulator-superfluid transition is explored

through general scaling arguments, exact model calculations in one dimension,

numerical results in two dimensions, and approximate renormalization group

results in higher dimensions. Experiments on He-4 adsorbed in porous Vycor

glass, on thin film superconductors, and magnetically trapped atomic vapors in

a periodic optical potential, are used to illustrate many of the concepts.

\\ ( http://arxiv.org/abs/0810.3263 , 246kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3379

Date: Sun, 19 Oct 2008 09:31:52 GMT (543kb)

Title: Making vortices in dipolar spinor condensates via rapid adiabatic

passage

Authors: J.-N. Zhang, L. He, H. Pu, C.-P. Sun, and S. Yi

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

Comments: 4 pages, 4 figures

\\

We propose to the create vortices in spin-1 condensates via magnetic

dipole-dipole interaction. Starting with a polarized condensate prepared under

large axial magnetic field, we show that by gradually inverting the field,

population transfer among different spin states can be realized in a controlled

manner. Under optimal condition, we generate a doubly quantized vortex state

containing nearly all atoms in the condensate. The resulting vortex state is a

direct manifestation of the dipole-dipole interaction and spin textures in

spinor condensates. We also point out that the whole process can be

qualitatively described by a simple rapid adiabatic passage model.

\\ ( http://arxiv.org/abs/0810.3379 , 543kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3545

Date: Mon, 20 Oct 2008 12:55:33 GMT (2425kb,D)

Title: Quantum noise squeezing and entanglement on the atomic clock transition

Authors: J. Appel, P.J. Windpassinger, D. Oblak, U.B. Hoff, N. Kjaergaard, E.S.

Polzik

Categories: quant-ph

\\

Squeezing of quantum fluctuations by means of entanglement is a well

recognized goal in the field of quantum information science and precision

measurements. In particular, squeezing the fluctuations via entanglement

between two-level atoms can improve the precision of atom clocks and of

spectroscopy in general. Here, we demonstrate 3.4 dB of metrologically relevant

squeezing and entanglement for 10^5 cold caesium atoms via a quantum

nondemolition (QND) measurement on the atom clock levels. We demonstrate the

effect of decoherence inherent to generation of entanglement via a QND

measurement and present a dichromatic QND scheme which allows to minimize the

effect of this decoherence in metrological applications. The spin squeezing

method demonstrated here on the microwave caesium clock transition is

potentially applicable to optical lattice atom clocks.

\\ ( http://arxiv.org/abs/0810.3545 , 2425kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3288

Date: Sat, 18 Oct 2008 04:18:55 GMT (694kb)

Title: Effect of resonant interactions on the stability of a three-state Fermi

gas

Authors: J. H. Huckans, J. R. Williams, E. L. Hazlett, R. W. Stites, and K. M.

O'Hara

Categories: physics.atom-ph

\\

We investigate the stability of a three spin state mixture of ultracold

fermionic $^6$Li atoms over a range of magnetic fields encompassing three

Feshbach resonances. For most field values, we attribute decay of the atomic

population to three-body processes involving one atom from each spin state and

find that the three-body loss coefficient varies by over four orders of

magnitude. We observe high stability when at least two of the three scattering

lengths are small, rapid loss near the Feshbach resonances, and two unexpected

resonant loss features. At our highest fields, where all pairwise scattering

lengths are approaching $a_t = -2140 a_0$, we measure a three-body loss

coefficient $L_3 \simeq 5\times 10^{-22} \mathrm{cm}^6/\mathrm{s}$ and a trend

toward lower decay rates for higher fields indicating that future studies of

color superfluidity and trion formation in a SU(3) symmetric Fermi gas may be

feasible.

\\ ( http://arxiv.org/abs/0810.3288 , 694kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3720

Date: Tue, 21 Oct 2008 14:49:43 GMT (335kb)

Title: On quenches in non-integrable quantum many-body systems: the

one-dimensional Bose-Hubbard model revisited

Authors: Guillaume Roux

Categories: cond-mat.str-el cond-mat.stat-mech

\\

When a quantum many-body system undergoes a quench, the time-averaged

density-matrix $\rho$ governs the time-averaged expectation value of any

observable. It is consequently the key object to look at when comparing results

with equilibrium predictions. We show that the weights of $\rho$ can be

efficiently computed with Lanczos diagonalization for large Hilbert spaces,

giving a systematic method for studying quenches. As an application, the

non-integrable Bose-Hubbard model is shown to display two regimes: one with an

approximate Boltzmann distribution for small quench amplitudes, and one where

the distributions do not follow standard equilibrium predictions. Some

thermodynamics features of $\rho$, like the energy fluctuations and the

entropy, are also discussed.

\\ ( http://arxiv.org/abs/0810.3720 , 335kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3763

Date: Tue, 21 Oct 2008 08:21:44 GMT (60kb)

Title: Feshbach-Einstein condensates

Authors: Valy G. Rousseau, Peter J.H. Denteneer

Categories: cond-mat.stat-mech

Comments: 4 pages, 6 figures

\\

We investigate the phase diagram of a two-species Bose-Hubbard model

describing atoms and molecules on a lattice, interacting via a Feshbach

resonance. We identify a region where the system exhibits an exotic super-Mott

phase and regions with phases characterized by atomic and/or molecular

condensates. Our approach is based on a recently developed exact quantum Monte

Carlo algorithm: the Stochastic Green Function algorithm with tunable

directionality. We confirm some of the results predicted by mean-field studies,

but we also find disagreement with these studies. In particular, we find a

phase with an atomic but no molecular condensate, which is missing in all

mean-field phase diagrams.

\\ ( http://arxiv.org/abs/0810.3763 , 60kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3775

Date: Tue, 21 Oct 2008 09:45:37 GMT (321kb)

Title: Quantum phases of light coupled to a periodic Bose-Einstein condensate

in a cavity

Authors: Aranya B. Bhattacherjee and ManMohan

Categories: cond-mat.stat-mech

Comments: 4 pages, 4 figures

\\

We study a composite photon-Bose condensed atoms (BEC) system in an optical

lattice confined in a cavity. We show that the system is able to produce an

effective photon-photon repulsion in the presence of an external pump. We

predict for the first time zero-temperature quantum phases of light coupled to

BEC in the photon blockade regime in the presence of an external pump.

\\ ( http://arxiv.org/abs/0810.3775 , 321kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3797

Date: Tue, 21 Oct 2008 10:50:33 GMT (26kb)

Title: Effective theory for the Goldstone field in the BCS-BEC crossover at T=0

Authors: Juan L. Ma\~nes and Manuel A. Valle

Categories: cond-mat.other cond-mat.supr-con

Comments: 27 pages

\\

We perform a detailed study of the effective Lagrangian for the Goldstone

mode of a superfluid Fermi gas at zero temperature in the whole BCS-BEC

crossover. By using a derivative expansion of the response functions, we derive

the most general form of this Lagrangian at the next to leading order in the

momentum expansion in terms of four coefficient functions. This involves the

elimination of all the higher order time derivatives by careful use of the

leading order field equations. In the infinite scattering length limit where

conformal invariance is realized, we show that the effective Lagrangian must

contain an unnoticed invariant combination of higher spatial gradients of the

Goldstone mode, while explicit couplings to spatial gradients of the trapping

potential are absent. Across the whole crossover, we determine all the

coefficient functions at the one-loop level, taking into account the dependence

of the gap parameter on the chemical potential in the mean-field approximation.

These results are analytically expressed in terms of elliptic integrals of the

first and second kind. We discuss the form of these coefficients in the extreme

BCS and BEC regimes and around the unitary limit, and compare with recent work

by other authors.

\\ ( http://arxiv.org/abs/0810.3797 , 26kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3812

Date: Tue, 21 Oct 2008 12:37:38 GMT (94kb)

Title: Anderson localization in a correlated fermionic mixture

Authors: O. Fialko and K. Ziegler

Categories: cond-mat.dis-nn

Comments: 5 pages, 4 figures

\\

A mixture of two fermionic species with different masses is studied in an

optical lattice. The heavy fermions are subject only to thermal fluctuations,

the light fermions also to quantum fluctuations. We derive the Ising-like

distribution for the heavy atoms and study the localization properties of the

light fermions numerically by a transfer-matrix method. In a two-dimensional

system one-parameter scaling of the localization length is found with a

transition from delocalized states at low temperatures to localized states at

high temperature. The critical exponent of the localization length is

$\nu\approx 0.88$.

\\ ( http://arxiv.org/abs/0810.3812 , 94kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3833

Date: Tue, 21 Oct 2008 14:21:40 GMT (987kb)

Title: Unusual states of vortex matter in mixtures of Bose--Einstein

Condensates on rotating optical lattices

Authors: E. K. Dahl, E. Babaev, and A. Sudbo

Categories: cond-mat.stat-mech

Comments: 4 pages, 3 figures. Submitted to Physical Review

\\

A striking property of a single-component superfluid under rotation, is that

a broken symmetry in the order parameter results in a broken translational

symmetry, a vortex lattice. If translational symmetry is restored, the phase of

the order parameter disorders and the broken symmetry in the order parameter is

restored. We show that for Bose-Condensate mixtures on optical lattices (which

may possess a negative dissipationless intercomponent drag), a new situation

arises. A phase disordered nonsuperfluid component can break translational

symmetry in response to rotation due to interaction with a superfluid

component. This state is a modulated vortex liquid which breaks translational

symmetry in the direction transverse to the rotation vector.

\\ ( http://arxiv.org/abs/0810.3833 , 987kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3841

Date: Tue, 21 Oct 2008 14:26:01 GMT (605kb)

Title: Quantum micro-mechanics with ultracold atoms

Authors: Thierry Botter, Daniel Brooks, Subhadeep Gupta, Zhao-Yuan Ma, Kevin L.

Moore, Kater W. Murch, Tom P. Purdy, and Dan M. Stamper-Kurn

Categories: quant-ph

Comments: Proceedings of International Conference on Atomic Physics (ICAP) 2008

\\

In many experiments isolated atoms and ions have been inserted into

high-finesse optical resonators for the study of fundamental quantum optics and

quantum information. Here, we introduce another application of such a system,

as the realization of cavity optomechanics where the collective motion of an

atomic ensemble serves the role of a moveable optical element in an optical

resonator. Compared with other optomechanical systems, such as those

incorporating nanofabricated cantilevers or the large cavity mirrors of

gravitational observatories, our cold-atom realization offers direct access to

the quantum regime. We describe experimental investigations of optomechanical

effects, such as the bistability of collective atomic motion and the first

quantification of measurement backaction for a macroscopic object, and discuss

future directions for this nascent field.

\\ ( http://arxiv.org/abs/0810.3841 , 605kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3854

Date: Tue, 21 Oct 2008 14:59:10 GMT (80kb)

Title: Field Compensation of Field Frequency Shifts in the Ramsey Spectroscopy

of Clock Optical Transitions

Authors: A. V. Taichenachev, V. I. Yudin, C. W. Oates, Z. W. Barber and L.

Hollberg

Categories: physics.atom-ph physics.optics

Comments: 5 pages, 3 figures, RevTeX

\\

We develop the method of Ramsey spectroscopy with the use of an additional

field compensating the frequency shifts of clock optical transitions. This

method in combination with the method of magnetically induced excitation of

strongly forbidden transitions $^1S_0$$\to$$^3P_0$ [A.V. Taichenachev, et al.,

Phys. Rev. Lett. {\bf 96}, 083001 (2006)] allows the practically complete

compensation (down to the fractional level below 10$^{-17}$ with respect to the

unperturbed clock frequency) of field shifts of various origin for even

isotopes of alkaline-earth-like atoms confined to an optical lattice at magic

wavelength (lattice-based atomic clocks). Apart from this, the new method can

be used in the two-photon Doppler-free Ramsey spectroscopy of other forbidden

optical transitions (for example, $^1S_0$$\to$$^1S_0$ and $^1S_0$$\to$$^1D_2$)

and other atoms. This opens perspectives for development of principally new

variants of primary optical frequency standards based on free atoms. As a

whole, the method of the shift-compensating field is distinguished by

simplicity and high efficiency, and it can be applied for any transitions in

any atoms and ions.

\\ ( http://arxiv.org/abs/0810.3854 , 80kb)

------------------------------------------------------------------------------

\\

arXiv:0810.3876

Date: Tue, 21 Oct 2008 17:15:42 GMT (755kb)

Title: Four-body legacy of the Efimov effect

Authors: Javier von Stecher, Jose P. D'Incao, Chris H. Greene

Categories: physics.atom-ph

Comments: 19 pages, 6 figures

\\

Armed with a new solution to the four-body problem, we reanalyze the recent

Innsbruck observation of an Efimov resonance in three-body collisions of cesium

atoms, and show that it provides evidence of new, universal four-body physics

as well. Our theoretical treatment of four bosonic atoms in the limit of strong

two-body attraction suggests a ubiquitous result: namely, that resonantly-bound

states of all four atoms should occur whenever the two-body scattering length

is a specific fraction (0.43) of the value where a three-body Efimov resonance

occurs. A hitherto unanalyzed feature in the 2006 Innsbruck experiment supports

this universal prediction, and it provides the first known evidence to date

that a direct four-body recombination process plays a role. While we confirm

the conclusion reached previously by some studies that no true Efimov effect

exists for four particles, we demonstrate the existence of a universal class of

four-body states that are intimately connected with three-body Efimov states.

\\ ( http://arxiv.org/abs/0810.3876 , 755kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4111

Date: Wed, 22 Oct 2008 17:06:26 GMT (1094kb)

Title: Sagnac effect in a chain of mesoscopic quantum rings

Authors: Chris P. Search, John R. E. Toland, and Marko Zivkovic

Categories: cond-mat.mes-hall

\\

The ability to interferometrically detect inertial rotations via the Sagnac

effect has been a strong stimulus for the development of atom interferometry

because of the potential 10^{10} enhancement of the rotational phase shift in

comparison to optical Sagnac gyroscopes. Here we analyze ballistic transport of

matter waves in a one dimensional chain of N coherently coupled quantum rings

in the presence of a rotation of angular frequency, \Omega. We show that the

transmission probability, T, exhibits zero transmission stop gaps as a function

of the rotation rate interspersed with regions of rapidly oscillating finite

transmission. With increasing N, the transition from zero transmission to the

oscillatory regime becomes an increasingly sharp function of \Omega with a

slope \partialT/\partial \Omega N^2. The steepness of this slope dramatically

enhances the response to rotations in comparison to conventional single ring

interferometers such as the Mach-Zehnder and leads to a phase sensitivity well

below the standard quantum limit.

\\ ( http://arxiv.org/abs/0810.4111 , 1094kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4149

Date: Wed, 22 Oct 2008 23:05:08 GMT (275kb)

Title: Pairing instability driven by macroscopically degenerate collective

modes in two-dimensional rotating fermion liquids near unitarity

Authors: Predrag Nikolic

Categories: cond-mat.supr-con cond-mat.str-el

Comments: 4+ pages

\\

Fermionic superfluids can undergo phase transitions into different kinds of

normal regimes, loosely characterized by whether Cooper pairs remain locally

stable. If the normal phase retains strong pairing fluctuations, it behaves

like a liquid of vortices, which has been observed in cuprate superconductors.

We argue that analogous strongly correlated normal states exist in

two-dimensional neutral fermion liquids near unitarity, where superfluid is

destroyed by fast rotation. These states have non-universal properties, and if

they develop as distinct thermodynamic phases they can be characterized as

quantum Hall states of Cooper pairs. The formal analysis is based on a model

with SP(2N) symmetry that describes the quantum critical region in the vicinity

of a broad Feshbach resonance. We explore the pairing phase diagram and

demonstrate that the considered model has macroscopically degenerate bosonic

modes in the normal phase, to all orders in 1/N. It takes finite-range

interactions to lift this degeneracy, making the Abrikosov flux lattice of the

superfluid particularly susceptible to quantum melting.

\\ ( http://arxiv.org/abs/0810.4149 , 275kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4199

Date: Thu, 23 Oct 2008 02:38:23 GMT (407kb)

Title: Quantum dynamics of an instabiltiy-induced pulsation in a Bose-Einstein

condensate in an optical lattice

Authors: Uttam Shrestha, Juha Javanainen and Janne Ruostekoski

Categories: cond-mat.other

Comments: 13 pages

\\

We study the dynamics of a Bose-Einstein condensate (BEC) in a one

dimensional optical lattice in the limit of weak atom-atom interactions.

Numerically we find that a BEC may develop a pulsating instability in which

atoms nearly periodically collect themselves into a pulse and subsequently

disperse back into the initial homogeneous state. A qualitative explanation of

the quasi-periodic behavior is given by drawing an analogy with a double-well

system. In an extension we introduce quantum effects approximately within

Truncated Wigner Approximation (TWA). In pure classical mean field theory the

condensate shows an undamped pulsating instability, whereas we have observed a

damping in the oscillation when we average over many stochastic realizations.

\\ ( http://arxiv.org/abs/0810.4199 , 407kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4207

Date: Thu, 23 Oct 2008 05:08:37 GMT (1065kb)

Title: Localized matter-waves patterns with attractive interaction in rotating

potentials

Authors: Hidetsgu Sakaguchi and Boris Malomed

Categories: cond-mat.stat-mech cond-mat.mes-hall

Comments: 13 pages, 11 figures

\\

We consider a two-dimensional (2D) model of a rotating attractive

Bose-Einstein condensate (BEC), trapped in an external potential. First, an

harmonic potential with the critical strength is considered, which generates

quasi-solitons at the lowest Landau level (LLL). We describe a family of the

LLL quasi-solitons using both numerical method and a variational approximation

(VA), which are in good agreement with each other. We demonstrate that kicking

the LLL mode or applying a ramp potential sets it in the Larmor (cyclotron)

motion, that can also be accurately modeled by the VA.

\\ ( http://arxiv.org/abs/0810.4207 , 1065kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4206

Date: Thu, 23 Oct 2008 05:13:10 GMT (837kb)

Title: Quantum Optomechanics with Single Atom

Authors: Yue Chang, H. Ian, and C. P. Sun

Categories: quant-ph

Comments: 9 pages, 8 figures

\\

The recently increasing explorations for cavity optomechanical coupling

assisted by a single atom or an atomic ensemble have opened an experimentally

accessible fashion to interface quantum optics and nano (micro) -mechanical

systems. In this paper, we study in details such composite quantum dynamics of

photon, phonon and atoms, specified by the triple coupling, which only exists

in this triple hybrid system: The cavity QED system with a movable end mirror.

We exactly diagonalize the Hamiltonian of the triple hybrid system under the

parametric resonance condition. We find that, with the rotating-wave

approximation, the hybrid system is modeled by a generalized spin-orbit

coupling where the orbital angular momentum operator is defined through a

Jordan-Schwinger realization with two bosonic modes, corresponding to the

mirror oscillation and the single mode photon of the cavity. In the

quasi-classical limit of very large angular momentum, this system will behave

like a standard cavity-QED system described by the Jaynes-Cummings model as the

angular momentum operators are transformed to bosonic operators of a single

mode. We test this observation with an experimentally accessible system with

the atom in the cavity with a moving mirror.

\\ ( http://arxiv.org/abs/0810.4206 , 837kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4302

Date: Thu, 23 Oct 2008 15:31:18 GMT (308kb,D)

Title: Comparative study of semiclassical approaches to quantum dynamics

Authors: G.Schubert, V.S. Filinov, K. Matyash, R. Schneider, H. Fehske

Categories: quant-ph

Comments: 21 pages, 8 figures, submitted to J. Comp. Phys

\\

Quantum states can be described equivalently by density matrices, Wigner

functions or quantum tomograms. We analyze the accuracy and performance of

three related semiclassical approaches to quantum dynamics, in particular with

respect to their numerical implementation. As test cases, we consider the time

evolution of Gaussian wave packets in different one-dimensional geometries,

whereby tunneling, resonance and anharmonicity effects are taken into account.

The results and methods are benchmarked against an exact quantum mechanical

treatment of the system, which is based on a highly efficient Chebyshev

expansion technique of the time evolution operator.

\\ ( http://arxiv.org/abs/0810.4302 , 308kb)

------------------------------------------------------------------------------

\\

arXiv:0810.4208

Date: Thu, 23 Oct 2008 05:34:00 GMT (60kb)

Title: AC Stark shift of the Cs microwave atomic clock transitions

Authors: P. Rosenbusch, S. Ghezali, V. A. Dzuba, V. V. Flambaum, K. Beloy, A.

Derevianko

Categories: physics.atom-ph

\\

We analyze the AC Stark shift of the Cs microwave atomic clock transition

theoretically and experimentally. Theoretical and experimental data are in a

good agreement with each other. Results indicate the absence of a magic

wavelength at which there would be no differential shift of the clock states

having zero projections of the total angular momentum.

\\ ( http://arxiv.org/abs/0810.4208 , 60kb)

------------------------------------------------------------------------------

The replacements:

------------------------------------------------------------------------------

\\

arXiv:0807.2979

replaced with revised version Mon, 20 Oct 2008 13:03:07 GMT (58kb)

Title: The two-body problem of ultra-cold atoms in a harmonic trap

Authors: Patrick Shea, Brandon P. van Zyl, Rajat K. Bhaduri

Categories: physics.atom-ph cond-mat.other

Comments: Final version accepted for publication in Am. Journ. Phys

\\ ( http://arxiv.org/abs/0807.2979 , 58kb)

------------------------------------------------------------------------------

\\

arXiv:0808.3552

replaced with revised version Mon, 20 Oct 2008 06:57:47 GMT (675kb,D)

Title: Dynamical thermalization and vortex formation in stirred 2D

Bose-Einstein condensates

Authors: T. M. Wright, R. J. Ballagh, A. S. Bradley, P. B. Blakie, and C. W.

Gardiner

Categories: cond-mat.other

Comments: 22 pages, 15 figures. v2: Minor refinements made at suggestion of

referee. Discussion of other treatments revised. To appear in Phys. Rev. A

\\ ( http://arxiv.org/abs/0808.3552 , 675kb)

------------------------------------------------------------------------------

\\

arXiv:0809.4652

replaced with revised version Tue, 21 Oct 2008 22:27:24 GMT (386kb)

Title: Condensation of ideal Bose gas from the analysis of canonical partition

function

Authors: Jeong-Hyuck Park and Sang-Woo Kim

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

Comments: 5 pages, 1 color figure, computing code included; title changed,

presentation improved

\\ ( http://arxiv.org/abs/0809.4652 , 386kb)

------------------------------------------------------------------------------

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 Thu Oct 30 2008 - 09:35:43 EST

*
This archive was generated by hypermail 2.2.0
: Mon Nov 10 2008 - 13:55:45 EST
*