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

Date: Fri, 11 Sep 2009 19:46:06 +1000

Date: Fri, 11 Sep 2009 19:46:06 +1000

Dear subscribers,

Another busy week with 28 new preprints and 17 replacements.

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arXiv:0907.5436

Date: Thu, 30 Jul 2009 21:58:50 GMT (75kb)

Title: Low-dimensional weakly interacting Bose gases: non-universal equations

of state

Authors: G.E. Astrakharchik, J. Boronat, I.L. Kurbakov, Yu.E. Lozovik,

F.Mazzanti

Categories: cond-mat.quant-gas

Comments: 11 pages, 4 figures

\\

The zero-temperature equation of state is analyzed in low-dimensional bosonic

systems. In the dilute regime the equation of state is universal in terms of

the gas parameter, i.e. it is the same for different potentials with the same

value of the s-wave scattering length. Series expansions of the universal

equation of state are reported for one- and two- dimensional systems. We

propose to use the concept of energy-dependent s-wave scattering length for

obtaining estimations of non-universal terms in the energy expansion. We test

this approach by making a comparison to exactly solvable one-dimensional

problems and find that the generated terms have the correct structure. The

applicability to two-dimensional systems is analyzed by comparing with results

of Monte Carlo simulations. The prediction for the non-universal behavior is

qualitatively correct and the densities, at which the deviations from the

universal equation of state become visible, are estimated properly. Finally,

the possibility of observing the non-universal terms in experiments with

trapped gases is also discussed.

\\ ( http://arxiv.org/abs/0907.5436 , 75kb)

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arXiv:0907.5523

Date: Fri, 31 Jul 2009 13:18:35 GMT (51kb,D)

Title: Atom-dimer scattering and long-lived trimers in fermionic mixtures

Authors: J. Levinsen, T. G. Tiecke, J. T. M. Walraven, D. S. Petrov

Categories: cond-mat.quant-gas cond-mat.other

Comments: 4 pages, 2 figures

\\

We consider a heteronuclear fermionic mixture on the molecular side of an

interspecies Feshbach resonance and discuss atom-dimer scattering properties in

uniform space and in the presence of an external confining potential,

restricting the system to a quasi-2D geometry. We find that there is a peculiar

atom-dimer p-wave resonance which can be tuned by changing the frequency of the

confinement. Our results have implications for the ongoing experiments on

Lithium-Potassium mixtures, where this mechanism allows for switching the

p-wave interaction between a K atom and Li-K dimer from attractive to

repulsive, and forming a weakly bound trimer with unit angular momentum. We

show that such trimers are long-lived and the atom-dimer resonance does not

enhance inelastic relaxation in the mixture, making it an outstanding candidate

for studies of p-wave resonance effects in a many-body system.

\\ ( http://arxiv.org/abs/0907.5523 , 51kb)

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arXiv:0906.0016

Date: Fri, 29 May 2009 23:39:06 GMT (125kb)

Date (revised v2): Fri, 31 Jul 2009 19:03:14 GMT (82kb)

Title: Entanglement Entropy and Mutual Information in Bose-Einstein Condensates

Authors: Wenxin Ding, Kun Yang

Categories: quant-ph cond-mat.quant-gas

Comments: 12 pages, 6 figures

Journal-ref: Phys. Rev. A 80, 012329 (2009)

DOI: 10.1103/PhysRevA.80.012329

\\

In this paper we study the entanglement properties of free {\em

non-relativistic} Bose gases. At zero temperature, we calculate the bipartite

block entanglement entropy of the system, and find it diverges logarithmically

with the particle number in the subsystem. For finite temperatures, we study

the mutual information between the two blocks. We first analytically study an

infinite-range hopping model, then numerically study a set of long-range

hopping models in one-deimension that exhibit Bose-Einstein condensation. In

both cases we find that a Bose-Einstein condensate, if present, makes a

divergent contribution to the mutual information which is proportional to the

logarithm of the number of particles in the condensate in the subsystem. The

prefactor of the logarithmic divergent term is model dependent.

\\ ( http://arxiv.org/abs/0906.0016 , 82kb)

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arXiv:0907.5525

Date: Fri, 31 Jul 2009 12:42:04 GMT (6kb)

Title: Semiclassical Dynamics from Zeno-Like measurements

Authors: R.Rossi Jr., K.M. Fonseca, Romero M.C.Nemes

Categories: quant-ph

\\

The usual semiclassical approximation for atom-field dynamics consists in

substituting the field operators by complex numbers related to the (supposedly

large enough) intensity of the field. We show that a semiclassical evolution

for coupled systems can always be obtained by frequent Zeno-like measurements

on the state of one subsystems, independently of the field intensity in the

example given. We study the Jaynes Cummings model from this perspective.

\\ ( http://arxiv.org/abs/0907.5525 , 6kb)

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arXiv:0907.5534

Date: Fri, 31 Jul 2009 13:43:33 GMT (756kb,D)

Title: 1D cold photoassociative ionization of Na inside a storage ring

Authors: R. Paiva, R. Muhammad, R. Shiozaki, A. L. de Oliveira, K. M. F.

Magalh\~aes, O. Morizot, and V. S. Bagnato

Categories: physics.atom-ph

\\

Motivated by recent interest in low dimensional arrays of atoms, we

experimentally investigated the way cold collisional processes are affected by

the geometry of the considered atomic sample. More specifically, we studied the

case of photoassociative ionization (PAI) both in a unidimensional and a

tridimensionnal system. First, creating a ring shaped trap (atomotron) we

investigated twocolor PAI dependence with intensity and polarization of a

probing laser. The intensity dependence of the PAI rate was also measured in a

magneto-optical trap presenting equivalent temperature band density conditions.

Indeed, the results show that in the ring trap, the value of the PAI rate

constant is much lower and does not saturate, unlike in the case of the 3D-MOT.

Control of cold atomic collisions inside almost 1D system constitutes a whole

new field of investigation.

\\ ( http://arxiv.org/abs/0907.5534 , 756kb)

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arXiv:0907.4420

Date: Sat, 25 Jul 2009 12:56:36 GMT (179kb)

Title: Localization in excitation number space of a strongly interacting

Rydberg gas

Authors: B. Olmos, M. M\"uller, I. Lesanovsky

Categories: cond-mat.quant-gas cond-mat.stat-mech physics.atom-ph

Comments: submitted to NJP focus issue on 'Dynamics and Thermalization in

Isolated Quantum Many-Body Systems'

\\

When Rydberg states are excited in a dense atomic gas the mean number of

excited atoms reaches a stationary value after an initial transient period. We

shed light on the origin of this steady state that emerges from a purely

coherent evolution of a closed system. To this end we consider a

one-dimensional ring lattice, and employ the perfect blockade model, i.e. the

simultaneous excitation of Rydberg atoms occupying neighboring sites is

forbidden. We derive an equation of motion which governs the system's evolution

in excitation number space. This equation possesses a steady state which is

strongly localized. Our findings show that this state is to a good accuracy

given by the density matrix of the microcanonical ensemble where the

corresponding microstates are the zero energy eigenstates of the interaction

Hamiltonian.

\\ ( http://arxiv.org/abs/0907.4420 , 179kb)

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arXiv:0908.0072

Date: Sat, 1 Aug 2009 12:08:25 GMT (894kb)

Title: Quantum phase diagrams of fermionic dipolar gases for an arbitrary

orientation of dipole moment in a planar array of 1D tubes

Authors: Yi-Ping Huang and Daw-Wei Wang

Categories: cond-mat.quant-gas cond-mat.str-el

Comments: 10 pages and 10 figures

\\

We systematically study ground state properties of fermionic dipolar gases in

a planar array of one-dimensional potential tubes for an arbitrary orientation

of dipole moments. Using the Luttinger liquid theory with the generalized

Bogoliubov transformation, we calculate the elementary excitations and the

Luttinger scaling exponents for various relevant quantum orders. The complete

quantum phase diagrams for arbitrary polar angle of the dipole moment is

obtained, including charge density wave, p-wave superfluid, inter-tube

gauge-phase density wave, and inter-tube s-wave superfluid, where the last two

breaks the U(1) gauge symmetry of the system (conservation of particle number

in each tube) and occurs only when the inter-tube interaction is larger than

the intra-tube interaction. We then discuss the physical properties of these

many-body phases and their relationship with some solid state systems.

\\ ( http://arxiv.org/abs/0908.0072 , 894kb)

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arXiv:0908.0174

Date: Mon, 3 Aug 2009 01:25:57 GMT (494kb)

Title: A quantum gas microscope - detecting single atoms in a Hubbard regime

optical lattice

Authors: Waseem S. Bakr, Jonathon I. Gillen, Amy Peng, Simon Foelling, Markus

Greiner

Categories: cond-mat.quant-gas

\\

Recent years have seen tremendous progress in creating complex atomic

many-body quantum systems. One approach is to use macroscopic, effectively

thermodynamic ensembles of ultracold atoms to create quantum gases and strongly

correlated states of matter, and to analyze the bulk properties of the

ensemble. The opposite approach is to build up microscopic quantum systems atom

by atom - with complete control over all degrees of freedom. Until now, the

macroscopic and microscopic strategies have been fairly disconnected. Here, we

present a "quantum gas microscope" that bridges the two approaches, realizing a

system where atoms of a macroscopic ensemble are detected individually and a

complete set of degrees of freedom of each of them is determined through

preparation and measurement. By implementing a high-resolution optical imaging

system, single atoms are detected with near-unity fidelity on individual sites

of a Hubbard regime optical lattice. The lattice itself is generated by

projecting a holographic mask through the imaging system. It has an arbitrary

geometry, chosen to support both strong tunnel coupling between lattice sites

and strong on-site confinement. On one hand, this new approach can be used to

directly detect strongly correlated states of matter. On the other hand, the

quantum gas microscope opens the door for the addressing and read-out of

large-scale quantum information systems with ultracold atoms.

\\ ( http://arxiv.org/abs/0908.0174 , 494kb)

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arXiv:0908.0236

Date: Mon, 3 Aug 2009 12:03:20 GMT (479kb)

Title: The imbalanced antiferromagnet in an optical lattice

Authors: Arnaud Koetsier, F. van Liere and H. T. C. Stoof

Categories: cond-mat.quant-gas

Comments: 4 pages, 5 figures, RevTeX

Report-no: ITP-UU-09/20

\\

We study the rich properties of the imbalanced antiferromagnet in an optical

lattice. We present its phase diagram, discuss spin waves and explore the

emergence of topological excitations in two dimensions, known as merons, which

are responsible for a Kosterlitz-Thouless transition that has never

unambiguously been observed.

\\ ( http://arxiv.org/abs/0908.0236 , 479kb)

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arXiv:0908.0248

Date: Mon, 3 Aug 2009 13:46:19 GMT (147kb)

Title: Bose-Einstein condensation of alkaline earth atoms: $^{40}${Ca}

Authors: Sebastian Kraft, Felix Vogt, Oliver Appel, Fritz Riehle, and Uwe Sterr

Categories: cond-mat.quant-gas

\\

We have achieved Bose-Einstein condensation of $^{40}$Ca, the first for an

alkaline earth element. The influence of elastic and inelastic collisions

associated with the large ground state s-wave scattering length of $^{40}$Ca

was measured. From these findings, an optimized loading and cooling scheme was

developed that allowed us to condense about $2 \cdot 10^4$ atoms after laser

cooling in a two-stage magneto-optical trap and subsequent forced evaporation

in a crossed dipole trap within less than 3 s. The condensation of an alkaline

earth element opens novel opportunities for precision measurements on the

narrow intercombination lines as well as investigations of molecular states at

the $^1$S--$^3$P asymptotes.

\\ ( http://arxiv.org/abs/0908.0248 , 147kb)

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arXiv:0908.0300

Date: Mon, 3 Aug 2009 17:00:27 GMT (9kb)

Title: Supersymmetry representation of Bose-Einstein condensation of fermion

pairs

Authors: Alexander Olemskoi, Irina Shuda

Categories: cond-mat.stat-mech

Comments: 5 pages, 0 figures

\\

We consider supersymmetry field theory with supercomponents being the square

root of the Bose condensate density, the amplitude of its fluctuations and

Grassmannian fields related to the Fermi particles density. The fermion number

is demonstrated to be conserved in degenerated Fermi-Bose mixtures with

unbroken supersymmetry when the system is invariant with respect to inversion

of the time arrow. We show the supersymmetry breaking allows one to derive

field equations describing behavior of real Bose-Fermi mixtures. Solution of

related field equations reveals the cooling of homogeneously distributed

fermions gives first spontaneous rise to strong inhomogeneous fluctuations,

while the Bose condensate appears at a lower temperature dependent of the

fermion density.

\\ ( http://arxiv.org/abs/0908.0300 , 9kb)

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arXiv:0908.0243

Date: Mon, 3 Aug 2009 13:25:45 GMT (105kb)

Title: Photon Wavepacket Manipulation via Space and Time dependent

Electromagnetically Induced Transparency

Authors: Francesco Bariani, Iacopo Carusotto

Categories: quant-ph

\\

We present a Maxwell-Bloch description of the dynamics of a light pulse

propagating through a spatially inhomogeneous system consisting of alternating

layers of EIT media and vacuum. We study the effect of a dynamical modulation

of the EIT control field on the shape of the wavepacket: interesting effects

due to the presence of interfaces with group velocity mismatch are found. An

effective description based on a continuity equation is developed. Modulation

schemes that can be realized in ultracold atomic samples with standard

experimental techniques are proposed and discussed.

\\ ( http://arxiv.org/abs/0908.0243 , 105kb)

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arXiv:0908.0263

Date: Mon, 3 Aug 2009 16:18:40 GMT (763kb)

Title: Imaging-based Parametric Resonance in an Optical Dipole Atom Trap

Authors: S. Balik, A.L. Win and M.D. Havey

Categories: quant-ph

Comments: To appear in PHYSICAL REVIEW A 80, (2009)

\\

We report sensitive detection of parametric resonances in a high-density

sample of ultracold $^{87}Rb$ atoms confined to a far-off-resonance optical

dipole trap. Fluorescence imaging of the expanded ultracold atom cloud after a

period of parametric excitation shows significant modification of the atomic

spatial distribution and has high sensitivity compared with traditional

measurements of parametrically-driven trap loss. Using this approach, a

significant shift of the parametric resonance frequency is observed, and

attributed to the anharmonic shape of the dipole trap potential.

\\ ( http://arxiv.org/abs/0908.0263 , 763kb)

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arXiv:0908.0275

Date: Mon, 3 Aug 2009 15:34:40 GMT (2284kb)

Title: Coherent Excitation of Rydberg Atoms in Thermal Vapor Microcells

Authors: H. K\"ubler, J. P. Shaffer, T. Baluktsian, R. L\"ow and T. Pfau

Categories: quant-ph

\\

The coherent control of mesoscopic ensembles of atoms and Rydberg atom

blockade are the basis for proposed quantum devices such as integrable gates

and single photon sources. So far, experimental progress has been limited to

complex experimental setups that use ultracold atoms. Here, we show that

coherence times of ~100ns are achievable with coherent Rydberg atom

spectroscopy in um sized thermal vapor cells. We investigated states with

principle quantum numbers between 30 and 50. Our results demonstrate that

microcells with a size on the order of the blockade radius, ~2um, at

temperatures of 100-300C are robust, promising candidates to investigate low

dimensional strongly interacting Rydberg gases, construct quantum gates and

build single photon sources.

\\ ( http://arxiv.org/abs/0908.0275 , 2284kb)

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arXiv:0908.0279

Date: Mon, 3 Aug 2009 15:29:15 GMT (402kb)

Title: Solid-state laser system for laser cooling of Sodium

Authors: Emmanuel Mimoun, Luigi de Sarlo, Jean-Jacques Zondy, Jean Dalibard and

Fabrice Gerbier

Categories: physics.optics

\\

We demonstrate a frequency-stabilized, all-solid laser source at 589 nm with

up to 800 mW output power. The laser relies on sum-frequency generation from

two laser sources at 1064 nm and 1319 nm through a PPKTP crystal in a

doubly-resonant cavity. We obtain conversion efficiency as high as 2 W/W^2

after optimization of the cavity parameters. The output wavelength is tunable

over 60 GHz, which is sufficient to lock on the Sodium D2 line. The robustness,

beam quality, spectral narrowness and tunability of our source make it an

alternative to dye lasers for atomic physics experiments with Sodium atoms.

\\ ( http://arxiv.org/abs/0908.0279 , 402kb)

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arXiv:0908.0478

Date: Tue, 4 Aug 2009 15:51:21 GMT (232kb,D)

Title: Blockade and superdrag in exciton-condensate Josephson junctions

Authors: Fabrizio Dolcini, Diego Rainis, Fabio Taddei, Marco Polini, Rosario

Fazio, A.H. MacDonald

Categories: cond-mat.mes-hall cond-mat.supr-con

Comments: 5 pages, 2 figures

\\

Boson and Fermion-pair condensation are the most remarkable phenomena in

statistical physics because they promote quantum behaviour from the microscopic

to the macroscopic world. In this Letter we examine the conversion of charged

supercurrents in superconductors (Cooper pair condensates) into neutral

supercurrents in electron-hole pair (exciton) condensates. We show that perfect

conversion is possible via a new pair Andreev-like scattering mechanism.

Because neutral currents are protected from electrical noise, this property

could have important applications in the design of coherent electronic devices.

\\ ( http://arxiv.org/abs/0908.0478 , 232kb)

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arXiv:0908.0377

Date: Tue, 4 Aug 2009 03:06:54 GMT (41kb)

Title: Ultrafast stimulated Raman parallel adiabatic passage by shaped pulses

Authors: G. Dridi, S. Guerin, V. Hakobyan, H.R. Jauslin, H. Eleuch

Categories: quant-ph

Comments: 5 pages, 4 figures

\\

We present a general and versatile technique of population transfer based on

{\it parallel adiabatic passage} by femtosecond shaped pulses. Their amplitude

and phase are specifically designed to optimize the adiabatic passage

corresponding to parallel eigenvalues at all times. We show that this technique

allows the robust adiabatic population transfer in a Raman system with the

total pulse area as low as 3 $\pi$, corresponding to a fluence of one order of

magnitude below the conventional stimulated Raman adiabatic passage process.

This process of short duration, typically pico- and subpicosecond, is easily

implementable with the modern pulse shaper technology and opens the possibility

of ultrafast robust population transfer with interesting applications in

quantum information processing.

\\ ( http://arxiv.org/abs/0908.0377 , 41kb)

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arXiv:0908.0454

Date: Tue, 4 Aug 2009 14:31:05 GMT (562kb)

Title: Entanglement of two individual neutral atoms using Rydberg blockade

Authors: T. Wilk, A. Ga\"etan, C. Evellin, J. Wolters, Y. Miroshnychenko, P.

Grangier, and A. Browaeys

Categories: quant-ph

\\

We report the generation of entanglement between two individual 87Rb atoms in

hyperfine ground states |F=1,M=1> and |F=2,M=2> which are held in two optical

tweezers separated by 4 $\mu$m. Our scheme relies on the Rydberg blockade

effect which prevents the simultaneous excitation of the two atoms to a Rydberg

state. The entangled state is generated in about 200 ns using pulsed two-photon

excitation. We quantify the entanglement by applying global Raman rotations on

both atoms. Correcting for losses we measure a fidelity of 0.75 with respect to

the target state.

\\ ( http://arxiv.org/abs/0908.0454 , 562kb)

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arXiv:0908.0209 (*cross-listing*)

Date: Mon, 3 Aug 2009 09:25:18 GMT (16kb)

Title: Towards Relativistic Atomic Physics and Post-Minkowskian Gravitational

Waves

Authors: Luca Lusanna (INFN)

Categories: gr-qc astro-ph.GA hep-th physics.atom-ph

Comments: Talk at the Workshop on {\it Gravitational Waves Detection with Atom

Interferometry}, held in Firenze at the Galileo Galilei Institute for

Theoretical Physics, February 23-24, 2009, 13 p

\\

A review is given of the formulation of relativistic atomic theory, in which

there is an explicit realization of the Poincare' generators, both in the

inertial and in the non-inertial rest-frame instant form of dynamics in

Minkowski space-time. This implies the need to solve the problem of the

relativistic center of mass of an isolated system and to describe the

transitions from different conventions for clock synchronization, namely for

the identifications of instantaneous 3-spaces, as gauge transformations. These

problems, stemming from the Lorentz signature of space-time, are a source of

non-locality, which induces a spatial non-separability in relativistic quantum

mechanics, with implications for relativistic entanglement. Then the classical

system of charged particles plus the electro-magnetic field is studied in the

framework of ADM canonical tetrad gravity in asymptotically Minkowskian

space-times admitting the ADM Poincare' group at spatial infinity, which allows

to get the general relativistic extension of the non-inertial rest frames of

special relativity. The use of the York canonical basis allows to disentangle

the tidal degrees of freedom of the gravitational field from the inertial ones.

The York time is the inertial gauge variable describing the general

relativistic remnant of the gauge freedom in clock synchronization. However now

each solution of Einstein's equations dynamically determines a preferred notion

of instantaneous 3-spaces. The linearization of this canonical formulation in

the weak field approximation will allow to find Hamiltonian Post-Minkowskian

gravitational waves with an asymptotic background and without Post-Newtonian

expansion in non-harmonic 3-orthogonal gauges.

\\ ( http://arxiv.org/abs/0908.0209 , 16kb)

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arXiv:0908.0590

Date: Wed, 5 Aug 2009 06:05:07 GMT (486kb)

Title: Detecting Bose-Einstein condensation of exciton-polaritons via electron

transport

Authors: Yueh-Nan Chen, Neill Lambert, Franco Nori

Categories: cond-mat.mes-hall cond-mat.quant-gas

Comments: 5 Pages, 3 Figures

\\

We examine the Bose-Einstein condensation of exciton-polaritons in a

semiconductor microcavity via an electrical current. We propose that by

embedding a quantum dot p-i-n junction inside the cavity, the tunneling current

through the device can reveal features of condensation due to a one-to-one

correspondence of the photons to the condensate polaritons. Such a device can

also be used to observe the phase interference of the order parameters from two

condensates.

\\ ( http://arxiv.org/abs/0908.0590 , 486kb)

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arXiv:0908.0608

Date: Wed, 5 Aug 2009 07:55:05 GMT (137kb)

Title: Ground state of a tightly bound composite dimer immersed in a Fermi Sea

Authors: Christophe Mora (LPA), Fr\'ed\'eric Chevy (LKB - Lhomond)

Categories: cond-mat.quant-gas

Comments: 11 pages; 3 figures

\\

In this paper we present a theoretical investigation for the ground state of

an impurity immersed in a Fermi sea. The molecular regime is considered where a

two-body bound state between the impurity and one of the fermions is formed.

Both interaction and exchange of the bound fermion take place between the dimer

and the Fermi sea. We develop a formalism based on a two channel model allowing

us to expand systematically the ground state energy of this immersed dimer with

the scattering length $a$. Working up to order $a^3$, associated to the

creation of two particle-hole pairs, reveals the first signature of the

composite nature of the bosonic dimer. Finally, a complementary variational

study provides an accurate estimate of the dimer energy even at large

scattering length.

\\ ( http://arxiv.org/abs/0908.0608 , 137kb)

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arXiv:0908.0692

Date: Wed, 5 Aug 2009 15:42:53 GMT (1931kb)

Title: Coherent ratchets in driven Bose-Einstein condensates

Authors: C.E. Creffield and F. Sols

Categories: cond-mat.quant-gas

Comments: 5 pages, 4 eps figures

\\

We study the response of a Bose-Einstein condensate to an unbiased periodic

driving potential. By controlling the space and time symmetries of the driving

we show how a directed current can be induced, producing a coherent quantum

ratchet. Weak driving induces a regular behavior that is strongly governed by

the interparticle interaction. Breaking both space and time symmetries is

required to produce current flow. For strong driving the behavior becomes

chaotic. The resulting effective irreversibility renders the space asymmetry

sufficient to produce the ratchet effect, although the system is completely

coherent.

\\ ( http://arxiv.org/abs/0908.0692 , 1931kb)

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arXiv:0908.0852

Date: Thu, 6 Aug 2009 12:39:20 GMT (1073kb,D)

Title: Universality in Ultra-Cold Few- and Many-Boson Systems

Authors: Martin Th{\o}gersen

Categories: cond-mat.quant-gas

Comments: Ph.D. dissertation. 145 pages, 48 figures

\\

This dissertation presents theoretical investigations of universality and

finite-range corrections in few- and many-boson systems. The main focus is on

ultra-cold atomic gases seen both from the three-body, many-body, and

mean-field perspective. Topics include corrections to Efimov physics, the

N-body Efimov effect, two-body correlations in condensates and higher-order

interactions in mean-field BECs.

\\ ( http://arxiv.org/abs/0908.0852 , 1073kb)

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arXiv:0908.0868

Date: Thu, 6 Aug 2009 13:20:46 GMT (158kb)

Title: Quantum critical states and phase transitions in the presence of non

equilibrium noise

Authors: Emanuele G. Dalla Torre, Eugene Demler, Thierry Giamarchi, Ehud Altman

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

Comments: 8 pages, 2 figures

\\

Quantum critical points are characterized by scale invariant correlations and

correspondingly long ranged entanglement. As such, they present fascinating

examples of quantum states of matter, the study of which has been an important

theme in modern physics. Nevertheless very little is known about the fate of

quantum criticality under non equilibrium conditions. In this paper we

investigate the effect of external noise sources on quantum critical points. It

is natural to expect that noise will have a similar effect to finite

temperature, destroying the subtle correlations underlying the quantum critical

behavior. Surprisingly we find that in many interesting situations the

ubiquitous 1/f noise preserves the critical correlations. The emergent states

show intriguing interplay of intrinsic quantum critical and external noise

driven fluctuations. We demonstrate this general phenomenon with specific

examples in solid state and ultracold atomic systems. Moreover our approach

shows that genuine quantum phase transitions can exist even under non

equilibrium conditions.

\\ ( http://arxiv.org/abs/0908.0868 , 158kb)

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arXiv:0908.0789

Date: Thu, 6 Aug 2009 03:41:08 GMT (631kb)

Title: Evidence for Ground- and Excited-State Efimov Trimers in a Three-State

Fermi Gas

Authors: J. R. Williams, E. L. Hazlett, J. H. Huckans, R. W. Stites, Y. Zhang

and K. M. O'Hara

Categories: quant-ph

Comments: 4 pages, 2 figures

\\

We observe enhanced three-body recombination in an ultracold three-component

$^6$Li Fermi gas with large but unequal scattering lengths attributable to an

excited Efimov trimer state near the three-atom scattering threshold. We find

excellent agreement between the measured three-body recombination rate and the

recombination rate calculated in the zero-range approximation where the only

free parameters are the Efimov parameters $\kappa_*$ and $\eta_*$. The value of

$\kappa_*$ determined by the location of the Efimov resonance we observe at 895

G also predicts the locations of loss features previously observed near 130 and

500 G \cite{Jochim08,OHara09} suggesting that all three features are associated

with universal Efimov trimer states. We also report on the first realization of

a quantum degenerate three-state Fermi gas with approximate SU(3) symmetry.

\\ ( http://arxiv.org/abs/0908.0789 , 631kb)

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arXiv:0908.0827

Date: Thu, 6 Aug 2009 09:33:07 GMT (135kb)

Title: Output entanglement and squeezing of two-mode fields generated by a

single atom

Authors: Ling Zhou, Qing-Xia Mu, Zhong-Ju Liu

Categories: quant-ph

Journal-ref: Phys. Lett. A 373, 2107 (2009)

\\

A single four-level atom interacting with two-mode cavities is investigated.

Under large detuning condition, we obtain the effective Hamiltonian which is

unitary squeezing operator of two-mode fields. Employing the input-output

theory, we find that the entanglement and squeezing of the output fields can be

achieved. By analyzing the squeezing spectrum, we show that asymmetric detuning

and asymmetric atomic initial state split the squeezing spectrum from one

valley into two minimum values, and appropriate leakage of the cavity is needed

for obtaining output entangled fields.

\\ ( http://arxiv.org/abs/0908.0827 , 135kb)

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arXiv:0908.0831

Date: Thu, 6 Aug 2009 09:45:03 GMT (105kb)

Title: Spontaneously generated atomic entanglement in free space: reinforced by

incoherent pumping

Authors: Ling Zhou, Guo Hui Yang, Anil K. Patnaik

Categories: quant-ph

Comments: have some difference with published version (please see PRA)

Journal-ref: Phys. Rev. A 79, 062102 (2009)

\\

We study spontaneously generated entanglement (SGE) between two identical

multilevel atoms in free space via vacuum-induced radiative coupling. We show

that the SGE in two-atom systems may initially increase with time but

eventually vanishes in the time scale determined by the excited state lifetime

and radiative coupling strength between the two atoms. We demonstrate that a

steady-state SGE can be established by incoherently pumping the excited states

of the two-atom system. We have shown that an appropriate rate of incoherent

pump can help producing optimal SGE. The multilevel systems offer us more

chanel to establish entanglement. The system under consideration could be

realized in a tight trap or atoms/ions doped in a solid substrate.

\\ ( http://arxiv.org/abs/0908.0831 , 105kb)

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\\

arXiv:0904.3221

Date: Tue, 21 Apr 2009 10:51:15 GMT (148kb)

Date (revised v2): Thu, 6 Aug 2009 14:43:19 GMT (149kb)

Title: Exact methods in analysis of nonequilibrium dynamics of integrable

models: application to the study of correlation functions in nonequilibrium

1D Bose gas

Authors: Vladimir Gritsev, Timofei Rostunov, Eugene Demler

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

Comments: 26 pages, 7 figures, minor corrections, refs added

\\

In this paper we study nonequilibrium dynamics of one dimensional Bose gas

from the general perspective of dynamics of integrable systems. After outlining

and critically reviewing methods based on inverse scattering transform,

intertwining operators, q-deformed objects, and extended dynamical conformal

symmetry, we focus on the form-factor based approach. Motivated by possible

applications in nonlinear quantum optics and experiments with ultracold atoms,

we concentrate on the regime of strong repulsive interactions. We consider

dynamical evolution starting from two initial states: a condensate of particles

in a state with zero momentum and a condensate of particles in a gaussian

wavepacket in real space. Combining the form-factor approach with the method of

intertwining operator we develop a numerical procedure which allows explicit

summation over intermediate states and analysis of the time evolution of

non-local density-density correlation functions. In both cases we observe a

tendency toward formation of crystal-like correlations at intermediate time

scales.

\\ ( http://arxiv.org/abs/0904.3221 , 149kb)

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The replacements:

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\\

arXiv:0804.1601

replaced with revised version Fri, 31 Jul 2009 16:00:33 GMT (588kb)

Title: On the Fundamental Equation of Nonequilibrium Statistical Physics and

Its Application -- Nonequilibrium Entropy Evolution Equation

Authors: Xiu-San Xing

Categories: cond-mat.stat-mech

Comments: 36 pages, 1 figure

\\ ( http://arxiv.org/abs/0804.1601 , 588kb)

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\\

arXiv:0902.3206

replaced with revised version Thu, 30 Jul 2009 21:06:47 GMT (130kb)

Title: Josephson oscillations in binary mixtures of F=1 spinor BECs

Authors: B. Julia-Diaz, M. Guilleumas, M. Lewenstein, A. Polls, A. Sanpera

Categories: cond-mat.other

Comments: Improved version. Accepted, Physical Review A

\\ ( http://arxiv.org/abs/0902.3206 , 130kb)

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\\

arXiv:0903.0895

replaced with revised version Thu, 30 Jul 2009 20:30:33 GMT (474kb)

Title: Quantum Quench from a Thermal Initial State

Authors: Spyros Sotiriadis, Pasquale Calabrese, John Cardy

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

Comments: 6 pages, 2 figures; short published version, added references, minor

changes

Journal-ref: EPL 87 (2009) 20002

DOI: 10.1209/0295-5075/87/20002

\\ ( http://arxiv.org/abs/0903.0895 , 474kb)

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\\

arXiv:0905.3634

replaced with revised version Fri, 31 Jul 2009 12:23:36 GMT (389kb)

Title: Black-hole radiation in Bose-Einstein condensates

Authors: Jean Macher and Renaud Parentani

Categories: cond-mat.quant-gas gr-qc

Comments: revTeX 4, 55 pages single-column, 19 figures; v2: figure and refs

added, typos corrected; v3: twocolumn, refs added/updated, new results,

presentation clarified

\\ ( http://arxiv.org/abs/0905.3634 , 389kb)

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\\

arXiv:0907.5053

replaced with revised version Fri, 31 Jul 2009 15:11:35 GMT (408kb)

Title: Construction of localized wave functions for a disordered optical

lattice and analysis of the resulting Hubbard model parameters

Authors: S. Q. Zhou and D. M. Ceperley

Categories: cond-mat.dis-nn

Comments: 10 pages, 16 figures

\\ ( http://arxiv.org/abs/0907.5053 , 408kb)

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\\

arXiv:0906.0016

replaced with revised version Fri, 31 Jul 2009 19:03:14 GMT (82kb)

Title: Entanglement Entropy and Mutual Information in Bose-Einstein Condensates

Authors: Wenxin Ding, Kun Yang

Categories: quant-ph cond-mat.quant-gas

Comments: 12 pages, 6 figures

Journal-ref: Phys. Rev. A 80, 012329 (2009)

DOI: 10.1103/PhysRevA.80.012329

\\ ( http://arxiv.org/abs/0906.0016 , 82kb)

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\\

arXiv:0907.5405

replaced with revised version Fri, 31 Jul 2009 19:28:04 GMT (479kb)

Title: Simulations of the Dipole-Dipole Interaction between Two Spatially

Separated Groups of Rydberg Atoms

Authors: T. J. Carroll (1), C. Daniel (1), L. Hoover (1), T. Sidie (1), and M.

W. Noel (2) ((1) Ursinus College, (2) Bryn Mawr College)

Categories: physics.atom-ph

Comments: 9 pages, 11 figures; fixed font issues in some figures and minor

typos

\\ ( http://arxiv.org/abs/0907.5405 , 479kb)

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\\

arXiv:0901.3770

replaced with revised version Mon, 3 Aug 2009 15:53:55 GMT (302kb,D)

Title: Three component fermion pairing in two dimensions

Authors: Theja N. De Silva

Categories: cond-mat.other

Comments: 6 pages and 5 figures. Published version

Journal-ref: Phys. Rev. A 80, 013620 (2009)

\\ ( http://arxiv.org/abs/0901.3770 , 302kb)

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\\

arXiv:0907.5389

replaced with revised version Sat, 1 Aug 2009 17:39:21 GMT (18kb)

Title: Fermion zero modes at the boundary of superfluid 3He-B

Authors: G.E. Volovik

Categories: cond-mat.other cond-mat.str-el hep-ph

Comments: 4 pages, no Figures, JETP Letters style

\\ ( http://arxiv.org/abs/0907.5389 , 18kb)

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\\

arXiv:0902.3564

replaced with revised version Mon, 3 Aug 2009 02:08:05 GMT (62kb)

Title: Perfect function transfer and interference effects in interacting boson

lattices

Authors: Lian-Ao Wu, Adam Miranowicz, XiangBin Wang, Yu-xi Liu, Franco Nori

Categories: quant-ph

Comments: 6 pages, 2 figures

Journal-ref: Phys. Rev. A 80, 012332 (2009)

DOI: 10.1103/PhysRevA.80.012332

\\ ( http://arxiv.org/abs/0902.3564 , 62kb)

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\\

arXiv:0811.2845

replaced with revised version Tue, 4 Aug 2009 03:14:33 GMT (633kb)

Title: Magnetic order, Bose-Einstein condensation, and superfluidity in the

bosonic t-J model of CP^1 spinons and doped Higgs holons

Authors: Koji Aoki, Kazuhiko Sakakibara, Ikuo Ichinose, Tetsuo Matsui

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

Comments: Title changed, Revised to a full paper. 14 pages, 17 figures

\\ ( http://arxiv.org/abs/0811.2845 , 633kb)

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\\

arXiv:0904.2927

replaced with revised version Tue, 4 Aug 2009 00:10:28 GMT (2831kb)

Title: Thermal effects in light scattering from ultracold bosons in an optical

lattice

Authors: Kazimierz {\L}akomy, Zbigniew Idziaszek, Marek Trippenbach

Categories: cond-mat.quant-gas quant-ph

Comments: The revised derivation of the formula describing the structure

function included. 14 pages, 12 figures

\\ ( http://arxiv.org/abs/0904.2927 , 2831kb)

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\\

arXiv:0902.2096

replaced with revised version Wed, 5 Aug 2009 17:50:00 GMT (346kb)

Title: Detection and engineering of spatial mode entanglement with ultra-cold

bosons

Authors: J. Goold, Libby Heaney, Th. Busch, V. Vedral

Categories: quant-ph cond-mat.mes-hall

Comments: 5 pages, 3 figures

\\ ( http://arxiv.org/abs/0902.2096 , 346kb)

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\\

arXiv:0906.2264

replaced with revised version Wed, 5 Aug 2009 13:27:34 GMT (864kb)

Title: Entropy exchange in a mixture of ultracold atoms

Authors: J. Catani, G. Barontini, G. Lamporesi, F. Rabatti, G. Thalhammer, F.

Minardi, S. Stringari, M. Inguscio

Categories: cond-mat.quant-gas

Comments: 5 pages, 4 figures

\\ ( http://arxiv.org/abs/0906.2264 , 864kb)

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\\

arXiv:0903.2945

replaced with revised version Wed, 5 Aug 2009 10:21:22 GMT (261kb)

Title: Atom cooling using the dipole force of a single retroreflected laser

beam

Authors: Andr\'e Xuereb, Peter Horak, Tim Freegarde

Categories: quant-ph

Comments: 9 pages, 11 figures. [v2: As published]

Journal-ref: Phys. Rev. A 80, 013836 (2009)

DOI: 10.1103/PhysRevA.80.013836

\\ ( http://arxiv.org/abs/0903.2945 , 261kb)

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\\

arXiv:0812.4174

replaced with revised version Thu, 6 Aug 2009 08:42:47 GMT (319kb)

Title: Fragmented many-body ground states for scalar bosons in a single trap

Authors: Philipp Bader and Uwe R. Fischer

Categories: cond-mat.other

Comments: 4 pages of RevTex4, 3 figures; as published in Physical Review

Letters

Journal-ref: Phys. Rev. Lett. 103, 060402 (2009)

DOI: 10.1103/PhysRevLett.103.060402

\\ ( http://arxiv.org/abs/0812.4174 , 319kb)

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\\

arXiv:0904.3221

replaced with revised version Thu, 6 Aug 2009 14:43:19 GMT (149kb)

Title: Exact methods in analysis of nonequilibrium dynamics of integrable

models: application to the study of correlation functions in nonequilibrium

1D Bose gas

Authors: Vladimir Gritsev, Timofei Rostunov, Eugene Demler

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

Comments: 26 pages, 7 figures, minor corrections, refs added

\\ ( http://arxiv.org/abs/0904.3221 , 149kb)

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Till next time,

Matt.

-- ========================================================================= Dr M. J. Davis, Associate Professor in Physics School of Mathematics and Physics, ph : +61 7 334 69824 The University of Queensland, fax : +61 7 336 51242 Brisbane, QLD 4072, mdavis_at_physics.uq.edu.au Australia. 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 ========================================================================= _______________________________________________ Matts-arxiv mailing list Matts-arxiv_at_lists.sps.uq.edu.auReceived on Thu Sep 24 2009 - 15:47:36 EST

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