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

Date: Mon, 28 Jul 2008 16:08:25 +1000

Date: Mon, 28 Jul 2008 16:08:25 +1000

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

Hi everyone,

Well I've been travelling in the USA for a little while and I've managed to fall

behind with the arXiv emails. With this message I have two more weeks to catch

up - hopefully by the end of the week.

This week there were 26 new preprints and 17 replacements:

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arXiv:0807.0726

Date: Fri, 4 Jul 2008 12:08:48 GMT (42kb)

Title: Critical velocities in two-component superfluid Bose gases

Authors: L.Yu. Kravchenko, D.V. Fil

Categories: cond-mat.other

Comments: 6 pages, 1 figures

Journal-ref: J. Low. Temp. Phys., 150, 612(2008)

\\

On the ground of the Landau criterion we study the behavior of critical

velocities in a superfluid two-component Bose gas. It is found that under

motion of the components with different velocities the velocity of each

component should not be lower than a minimum phase velocity of elementary

excitations (s_). The Landau criterion yields a relation between the critical

velocities of the components (v_{c1}, v_{c2}). The velocity of one or even both

components may exceed s_. The maximum value of the critical velocity of a given

component can be reached when the other component does not move. The approach

is generalized for a two-component condensate confined in a cylindrical

harmonic potential.

PACS numbers: 03.75.Kk,03.75.Mn

\\ ( http://arxiv.org/abs/0807.0726 , 42kb)

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arXiv:0807.0772

Date: Fri, 4 Jul 2008 14:52:39 GMT (49kb)

Title: Localization for one-dimensional random potentials with large local

fluctuations

Authors: Tom Bienaime and Christophe Texier

Categories: cond-mat.dis-nn

Comments: 8 pages, LaTeX, 2 eps figures

\\

We study the localization of wave functions for one-dimensional Schr\"odinger

Hamiltonian with random potentials $V(x)$ with short range correlations and

large local fluctuations such that $\int\D{x} \smean{V(x)V(0)}=\infty$.

Depending on how large the fluctuations of $V(x)$ are, we find either new

energy dependences of the localization length,

$\ell_\mathrm{loc}\propto{}E/\ln{E}$, $\ell_\mathrm{loc}\propto{}E^{\mu/2}$

with $0<\mu<2$ or $\ell_\mathrm{loc}\propto\ln^{\mu-1}E$ for $\mu>1$, or

superlocalization (decay of the wave functions faster than a simple

exponential).

\\ ( http://arxiv.org/abs/0807.0772 , 49kb)

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arXiv:0807.0790

Date: Mon, 7 Jul 2008 19:06:38 GMT (40kb)

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: 4 pages, 4 figures

\\

We perform a theoretical study of a fermionic gas with two hyperfine states

confined to an optical lattice. We derive a generic state diagram as a function

of interaction strength, particle number, and confining potential. We discuss

the double occupancy both as a thermometer and as a probe for the Mott state,

connecting our findings to the recent experiment of J\"ordens et al.

[arXiv:0804.4009]. Using entropic arguments we compare two different strategies

to reach the antiferromagnetic state in the presence of a trapping potential.

\\ ( http://arxiv.org/abs/0807.0790 , 40kb)

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arXiv:0807.0830

Date: Fri, 4 Jul 2008 22:48:56 GMT (371kb)

Title: Probing the Spectral Function Using Momentum Resolved Radio Frequency

Spectroscopy in Trapped Fermi Gases

Authors: Qijin Chen, and K. Levin

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

Comments: 5 pages, 4 figures

\\

We address recent momentum resolved radio frequency (RF) experiments on

ultracold trapped Fermi gases of $^{40}$K. We show that momentum resolved RF

probes provide measurements of the centrally important fermionic spectral

function. They also serve to remove ambiguity plaguing the interpretation of

momentum integrated RF experiments by establishing a clear dispersion signature

of pairing. We find that the temperature dependence of the spectral function is

dramatic at unitarity, and, importantly, smooth from above to below $T_c$

throughout BCS-BEC crossover. This should be tested experimentally, given

widespread predictions of first order behavior.

\\ ( http://arxiv.org/abs/0807.0830 , 371kb)

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arXiv:0807.0938

Date: Mon, 7 Jul 2008 03:38:36 GMT (5kb)

Title: Dilute Hard "Sphere" Bose Gas in Dimensions 2, 4 and 5

Authors: C.N. Yang

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

Comments: 3 pages

\\

The ground state energy for a dilute hard "sphere" Bose gas in various

dimensions is studied theoretically.

\\ ( http://arxiv.org/abs/0807.0938 , 5kb)

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arXiv:0807.0948

Date: Mon, 7 Jul 2008 05:53:02 GMT (250kb)

Title: Successive phase transitions at finite temperatures of the supersolid in

the three-dimensional extended Bose-Hubbard model

Authors: Keisuke Yamamoto and Synge Todo and Seiji Miyashita

Categories: cond-mat.stat-mech

Comments: 6 pages, 6 figures

\\

We study the finite temperature properties of the extended Bose-Hubbard model

on a cubic lattice. This model exhibits the so-called supersolid state. To

start with, we investigate ordering processes by quantum Monte Carlo

simulations, and find successive superfluid and solid phase transitions. There,

we find that the two order parameters compete with each other. We obtain the

finite temperature phase diagram, which contains the superfluid, the solid, the

supersolid and the disordered phase. We develop a mean-field theory to analyze

the ordering processes and compare the result with that obtained by

simulations, and discuss the mechanism of the competition of these two orders.

We also study how the supersolid region shrinks as the on-site repulsion

becomes strong.

\\ ( http://arxiv.org/abs/0807.0948 , 250kb)

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arXiv:0807.0980

Date: Mon, 7 Jul 2008 09:58:13 GMT (1476kb)

Title: Stochastic polarization formation in exciton-polariton Bose-Einstein

condensates

Authors: D. Read, P. J. Membry, T. C. H. Liew, Yuri G. Rubo, A. V. Kavokin

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

Comments: 4 pages, 3 figures

\\

We demonstrate theoretically the spontaneous formation of a stochastic

polarization in exciton-polariton Bose-Einstein condensates in planar

microcavities under pulsed excitation. Below the threshold pumping intensity

(dependent on the polariton life-time) the average polarization degree is close

to zero, whilst above threshold the condensate acquires a polarization

described by a (pseudospin) vector with random orientation, in general. We

establish the link between second order coherence of the polariton condensate

and the distribution function of its polarization. We examine also the

mechanisms of polarization dephasing and relaxation.

\\ ( http://arxiv.org/abs/0807.0980 , 1476kb)

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arXiv:0807.1034

Date: Mon, 7 Jul 2008 15:27:40 GMT (82kb,D)

Title: Pairing in ultracold Fermi gases in the lowest landau level

Authors: G. Moller, Th. Jolicoeur, N. Regnault

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

Comments: 11 pages, 9 figs (best viewed in color)

\\

We study a rapidly rotating gas of unpolarized spin-1/2 ultracold fermions in

the two-dimensional regime when all atoms reside in the lowest Landau level.

Due to the presence of the spin degree of freedom both s-wave and p-wave

interactions are allowed at ultralow temperatures. We investigate the phase

diagram of this system as a function of the filling factor of the lowest Landau

level and of the ratio between s- and p-wave interaction strengths. We show

that the presence of attractive interactions induces a wide regime of phase

separation with formation of maximally compact droplets that are either fully

polarized or spin-singlet. When there is no phase separation, we give evidence

for fractional quantum Hall states. Most notably we find that at the filling nu

= 2/3 there is a singlet state accounted for by composite fermion theory which

competes with an Abelian state of composite spin-singlet Bose molecules with

Laughlin correlations. By fine tuning of the scattering lengths it is possible

to create the non-Abelian critical Haldane-Rezayi state for nu = 1/2 and the

permanent state of Moore and Read for nu = 1. For purely repulsive

interactions, we also find evidence for a gapped Halperin state at nu = 2/5.

\\ ( http://arxiv.org/abs/0807.1034 , 82kb)

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arXiv:0807.0751

Date: Fri, 4 Jul 2008 13:24:54 GMT (1274kb)

Title: Quantum fluctuations in the image of a Bose gas

Authors: Antonio Negretti, Carsten Henkel, Klaus Molmer

Categories: quant-ph

Comments: 14 pages, 6 figures, Submitted to Phys. Rev. A

\\

We analyze the information content of density profiles for an ultracold Bose

gas of atoms and extract resolution limits for observables contained in these

images. Our starting point are density correlations that we compute within the

Bogoliubov approximation, taking into account quantum and thermal fluctuations

beyond mean-field theory. This provides an approximate way to construct the

joint counting statistics of atoms in an array of pixels covering the gas. We

derive the Fisher information of an image and the associated Cram\'er-Rao

sensitivity bound for measuring observables contained in the image. We

elaborate on our recent study on position measurements of a dark soliton [Phys.

Rev. A 77, 043606 (2008)] where a sensitivity scaling with the atomic density

as n^{-3/4} was found. We discuss here a wider class of soliton solutions and

present a detailed analysis of the Bogoliubov excitations and the gapless

(Goldstone) excitation modes. These fluctuations around the mean field

contribute to the noise in the image, and we show how they can actually improve

the ability to locate the position of the soliton.

\\ ( http://arxiv.org/abs/0807.0751 , 1274kb)

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arXiv:0807.0761

Date: Fri, 4 Jul 2008 14:18:02 GMT (103kb)

Title: Polarization-Mixing in Optical Lattices with Uniaxial Anisotropy

Authors: Hashem Zoubi and Helmut Ritsch

Categories: quant-ph

Comments: 10 pages, 19 figures

\\

We study optical excitations of an ultracold gas in an optical lattice in the

Mott insulator case and with anisotropic properties. The anisotropy is induced

by an oriented transition dipole generated by optical pumping and external

static fields, and is of the type of uniaxial crystals. Within a cavity, the

electronic excitations and the cavity photons of both TE and TM polarizations

are coherently mixed to form two polariton branches. Also a photonic branch

appears which decouples from the electronic transitions. The photon

polarization mixing can be observed by linear optical spectra. For example, for

an incident field of TE polarization we obtain TE and TM transmitted and

reflected fields. Also we calculate the phase shift in the TE and TM

transmitted and reflected fields relative to the incident field phase, which

lead to polarization rotations.

\\ ( http://arxiv.org/abs/0807.0761 , 103kb)

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arXiv:0807.0852

Date: Sat, 5 Jul 2008 10:23:57 GMT (660kb)

Title: Production of ultracold heteronuclear YbRb* molecules by

photoassociation

Authors: N. Nemitz, F. Baumer, F. M\"unchow, S. Tassy, A. G\"orlitz

Categories: quant-ph

\\

We have produced ultracold heteronuclear YbRb$^*$ molecules in a combined

magneto-optical trap by photoassociation. The formation of electronically

excited molecules close to the dissociation limit was observed by trap loss

spectroscopy in mixtures of $^{87}$Rb with $^{174}$Yb and $^{176}$Yb. The

molecules could be prepared in a series of vibrational levels with resolved

rotational structure, allowing for an experimental determination of the

long-range potential in the electronically excited state.

\\ ( http://arxiv.org/abs/0807.0852 , 660kb)

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arXiv:0807.0931

Date: Sun, 6 Jul 2008 23:10:16 GMT (93kb)

Title: Theory of Raman transitions in cavity QED

Authors: A. D. Boozer

Categories: quant-ph

Comments: 19 pages, 6 figures

\\

We present two schemes for driving Raman transitions between the ground state

hyperfine manifolds of a single atom trapped within a high-finesse optical

cavity. In both schemes, the Raman coupling is generated by standing-wave

fields inside the cavity, thus circumventing the optical access limitations

that free-space Raman schemes must face in a cavity system. These cavity-based

Raman schemes can be used to coherently manipulate both the internal and the

motional degrees of freedom of the atom, and thus provide powerful tools for

studying cavity quantum electrodynamics. We give a detailed theoretical

analysis of each scheme, both for a three-level atom and for a multi-level

cesium atom. In addition, we show how these Raman schemes can be used to cool

the axial motion of the atom to the quantum ground state, and we perform

computer simulations of the cooling process.

\\ ( http://arxiv.org/abs/0807.0931 , 93kb)

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arXiv:0807.1280

Date: Tue, 8 Jul 2008 18:16:06 GMT (541kb)

Title: Anisotropic Instabilities in Trapped Spinor Bose-Einstein Condensates

Authors: M. Baraban, H. F. Song, S. M. Girvin, L. I. Glazman

Categories: cond-mat.other

Comments: 8 pages, 6 figures

\\

We theoretically investigate the effect of an anisotropic trap on the

instability of the polar $(m_F=0)$ phase of a spin-1 Bose-Einstein condensate.

By considering rigorously the spatial quantization, we show that the growth of

the nascent ferromagnetic phase at short times becomes anisotropic with

stronger oscillations in the magnetization correlation function along the

unconfined direction.

\\ ( http://arxiv.org/abs/0807.1280 , 541kb)

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arXiv:0807.1144

Date: Mon, 7 Jul 2008 23:44:54 GMT (281kb)

Title: Controlling entanglement by direct quantum feedback

Authors: A. R. R. Carvalho, A. J. S. Reid, and J. J. Hope

Categories: quant-ph

Comments: 10 pages, 8 figures. To appear in PRA

\\

We discuss the generation of entanglement between electronic states of two

atoms in a cavity using direct quantum feedback schemes. We compare the effects

of different control Hamiltonians and detection processes in the performance of

entanglement production and show that the quantum-jump-based feedback proposed

by us in Phys. Rev. A {\bf 76} 010301(R) (2007) can protect highly entangled

states against decoherence. We provide analytical results that explain the

robustness of jump feedback, and also analyse the perspectives of experimental

implementation by scrutinising the effects of imperfections and approximations

in our model.

\\ ( http://arxiv.org/abs/0807.1144 , 281kb)

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arXiv:0807.1356

Date: Wed, 9 Jul 2008 00:43:47 GMT (408kb)

Title: Evaporative Cooling of a Photon Fluid to Quantum Degeneracy

Authors: B. T. Seaman and M. J. Holland

Categories: cond-mat.other physics.optics

\\

We demonstrate that the process of evaporative cooling, as associated with

the cooling of atomic gases, can also be employed to condense a system of

photons giving rise to coherent properties of the light. The system we study

consists of photons in a high-quality Fabry-Perot cavity with photon

interactions mediated by a nonlinear atomic medium. We predict a macroscopic

occupation of the lowest energy mode and evaluate the conditions for realizing

a narrow spectral width indicative of a long coherence time for the field.

\\ ( http://arxiv.org/abs/0807.1356 , 408kb)

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arXiv:0807.1433

Date: Wed, 9 Jul 2008 12:36:41 GMT (125kb)

Title: Non-Abelian magnetic monopole in a Bose-Einstein condensate

Authors: Ville Pietil\"a and Mikko M\"ott\"onen

Categories: cond-mat.other cond-mat.mes-hall

Comments: 5 pages, 1 color figure

\\

Recently, an effective non-Abelian magnetic field with a topology of a

monopole was shown to emerge from the adiabatic motion of multilevel atoms with

degenerate internal states in spatially varying laser fields [J. Ruseckas et

al., Phys. Rev. Lett. 95, 010404 (2005)]. In this work, we study this monopole

when the atoms in the degenerate adiabatic eigenstates form a Bose-Einstein

condensate. We show that the existence of the monopole is gauge dependent and

identify a gauge invariant topological charge describing the total magnetic

charge. From numerical calculations we conclude that the existence of the

non-Abelian magnetic monopole gives rise to a monopole with the same

topological charge in the pseudospin texture of the condensate.

\\ ( http://arxiv.org/abs/0807.1433 , 125kb)

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arXiv:0807.1450

Date: Wed, 9 Jul 2008 13:59:57 GMT (377kb)

Title: Fermionic superfluid properties in a one-dimensional optical lattice

Authors: Theja N. De Silva

Categories: cond-mat.other

Comments: 6 pages, 5 figures

\\

We discuss various superfluid properties of a two-component Fermi system in

the presence of a tight one-dimensional periodic potential in a

three-dimensional system. We use a zero temperature mean field theory and

derive analytical expressions for the Josephson current, the sound velocity and

the center of mass oscillations in the BCS-Bose Einstein condensation crossover

region.

\\ ( http://arxiv.org/abs/0807.1450 , 377kb)

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arXiv:0807.1503

Date: Wed, 9 Jul 2008 17:12:13 GMT (508kb)

Title: Theory for superfluidity in a Bose system

Authors: Zhidong Hao

Categories: cond-mat.supr-con

Comments: 15 pages 12 figures

\\

We present a microscopic theory for superfluidity in an interacting

many-particle Bose system (such as liquid $^4$He). The theory is based on an

assumption that particles of opposite momenta are paired in the superfluid

state, and thus, is similar to the BCS theory for superconductivity in

superconductors. The theory shows the existence of an energy gap in

single-particle excitation spectrum in the superfluid state. For the case where

superfluid velocity ${\bf v}_s=0$, the theory shows the existence of a specific

heat jump at the transition, indicating a second-order phase transition. The

theory is further extended to the case where superfluid velocity ${\bf v}_s\neq

0$. Critical velocity $v_{sc}$ for liquid $^4$He, for example, is shown to be

several tens of centimeters per second (i.e., $v_{sc}\sim 10 - 100$ cm/s). We

derive a relation between particle density current {\bf j} and superfluid

velocity ${\bf v}_s$ (this relation is analogous to the London equation for the

superconducting state), and calculate superfluid particle density $n_s$ as a

function of temperature $T$ and superfluid velocity ${\bf v}_s$. We also show

that free energy density $F$ is an increasing function of $v_s$ (i.e.,

$\partial F/\partial v_s > 0$), indicating that a superfluid tends to expel

superfluid velocity (this phenomenon is analogous to the Meissner effect in

superconductors). The similarity between the present theory and the BCS theory

of superconductivity shows that the cause for superconductivity in

superconductors and superfluidity in a Bose system (such as liquid $^4$He) is

essentially the same; i.e., they both arise from the pairing of the particles

involved.

\\ ( http://arxiv.org/abs/0807.1503 , 508kb)

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arXiv:0807.1446

Date: Wed, 9 Jul 2008 13:20:54 GMT (127kb)

Title: Electronic noise-free measurements of squeezed light

Authors: Leonid A. Krivitsky, Ulrik L. Andersen, Ruifang Dong, Alexander Huck,

Christoffer Wittmann, and Gerd Leuchs

Categories: quant-ph

Comments: submitted for publication

\\

We study the implementation of a correlation measurement technique for the

characterization of squeezed light. We show that the sign of the covariance

coefficient revealed from the time resolved correlation data allow us to

distinguish between squeezed, coherent and thermal states. In contrast to the

traditional method of characterizing squeezed light, involving measurement of

the variation of the difference photocurrent, the correlation measurement

method allows to eliminate the contribution of the electronic noise, which

becomes a crucial issue in experiments with dim sources of squeezed light.

\\ ( http://arxiv.org/abs/0807.1446 , 127kb)

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arXiv:0807.1448

Date: Wed, 9 Jul 2008 14:03:27 GMT (57kb)

Title: Bell test for the free motion of material particles

Authors: Clemens Gneiting, Klaus Hornberger

Categories: quant-ph

Comments: 5 pages, 1 figure

\\

We present a scheme to establish non-classical correlations in the motion of

two macroscopically separated massive particles without resorting to

entanglement in their internal degrees of freedom. It is based on the

dissociation of a diatomic molecule with two temporally separated Feshbach

pulses generating a motional state of two counter-propagating atoms that is

capable of violating a Bell inequality by means of correlated single particle

interferometry. We evaluate the influence of dispersion on the Bell

correlation, showing it to be important but manageable in a proposed

experimental setup. The latter employs a molecular BEC of fermionic Lithium

atoms, uses laser-guided atom interferometry, and seems to be within the reach

of present-day technology.

\\ ( http://arxiv.org/abs/0807.1448 , 57kb)

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arXiv:0807.1381

Date: Wed, 9 Jul 2008 06:41:11 GMT (44kb)

Title: Accurate calculations of Sr properties for a high-accuracy optical clock

Authors: S. G. Porsev, Andrew D. Ludlow, Martin M. Boyd, and Jun Ye

Categories: physics.atom-ph physics.gen-ph

Comments: 9 pages, 2 figures, 5 tables

\\

We have carried out calculations towards the goal of reducing the inaccuracy

of the Sr optical atomic clock to 1$\times10^{-17}$ and below. We calculated

a.c. polarizabilities of the $5s^2 ^1S_0$ and $5s5p ^3P_0^o$ clock states that

are important for reducing the uncertainty of blackbody radiation-induced

frequency shifts for the $^1S_0 - ^3P_0^o$ clock transition. We determined four

low-lying even-parity states whose total contribution to the static

polarizability of the $^3P_0^o$ clock state is at the level of 90%. We show

that if the contribution of these states is experimentally known with 0.1%

accuracy, the same accuracy can be achieved for the total polarizability of the

$^3P_0^o$ state. The corresponding uncertainty for the blackbody shift at a

fixed room temperature will be below 1$\times10^{-17}$. The calculations are

confirmed by a number of experimental measurements on various Sr properties.

\\ ( http://arxiv.org/abs/0807.1381 , 44kb)

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arXiv:0807.1438

Date: Wed, 9 Jul 2008 12:55:07 GMT (2430kb)

Title: Measurement of the hyperfine splitting of the 6S$_{1/2}$ level in

rubidium

Authors: A. Perez Galvan, Y. Zhao, L. A. Orozco

Categories: physics.atom-ph

Comments: 12 pages, 14 figures

Journal-ref: Phys. Rev. A 78, 012502 (2008)

\\

We present a measurement of the hyperfine splitting of the 6S$_{1/2}$ excited

level of rubidium using two photon absorption spectroscopy in a glass cell. The

values we obtain for the magnetic dipole constant A are 239.18(03) MHz and

807.66(08) MHz for $^{85}$Rb and $^{87}$Rb, respectively. The combination of

the magnetic moments of the two isotopes and our measurements show a hyperfine

anomaly in this atomic excited state. The observed hyperfine anomaly difference

has a value of $_{87}\delta_{85}=-0.0036(2)$ due to the finite distribution of

nuclear magnetization, the Bohr-Weisskopf effect.

\\ ( http://arxiv.org/abs/0807.1438 , 2430kb)

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arXiv:0807.1571

Date: Thu, 10 Jul 2008 03:06:17 GMT (662kb)

Title: Chiral magnon condensation in a quasi-1D spin liquid

Authors: V. O. Garlea, A. Zheludev, K. Habicht, M. Meissner, B. Grenier, L.-P.

Regnault, E. Ressouche

Categories: cond-mat.str-el

Comments: 4 pages

\\

Neutron scattering is used to study magnetic field induced ordering in the

quasi-1D quantum spin-tube compound Sul-Cu2Cl4. The experiments reveal an

incommensurate helimagnetic high-field phase stabilized by a geometric

frustration of the magnetic interactions. The measured critical exponents of

the transition at Hc ~ 3.7 Tesla and T -> 0 K are beta=0.235(2) and nu=0.34(3).

These values are distinct from those expected for a 3D Bose-Einstein

condensation. Several intriguing possible reasons for this discrepancy are

discussed.

\\ ( http://arxiv.org/abs/0807.1571 , 662kb)

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arXiv:0807.1622

Date: Thu, 10 Jul 2008 10:38:26 GMT (61kb)

Title: Superfluid equation of state of cold fermionic gases in the

Bose-Einstein regime

Authors: R. Combescot and X. Leyronas

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

Comments: 25 pages, 11 figures

\\

We present an exact many-body theory of ultracold fermionic gases for the

Bose-Einstein condensation (BEC) regime of the BEC-BCS crossover. This is a

purely fermionic approach which treats explicitely and systematically the

dimers formed in the BEC regime as made of two fermions. We consider

specifically the zero temperature case and calculate the first terms of the

expansion of the chemical potential in powers of the density $n$. We derive

first the mean-field contribution, which has the expected standard expression

when it is written in terms of the dimer-dimer scattering length $a_M$. We go

next in the expansion to the Lee-Huang-Yang order, proportional to $n^{3/2}$.

We find the far less obvious result that it retains also the same expression in

terms of $a_M$ as for elementary bosons. The composite nature of the dimers

appears only in the next term proportional to $n^2$.

\\ ( http://arxiv.org/abs/0807.1622 , 61kb)

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arXiv:0807.1691

Date: Thu, 10 Jul 2008 16:10:46 GMT (180kb)

Title: The role of particle interactions in a many-body model of Feshbach

molecular formation in bosonic systems

Authors: Jing Li, Di-Fa Ye, Chao Ma, Li-Bin Fu, Jie Liu

Categories: cond-mat.mes-hall

Comments: 7 pages, 5 figures

\\

In this paper, we investigate the atom-molecule conversion dynamics of a

generalized many-body model that includes the atom-atom, atom-molecule, and

molecule-molecule interactions, emphasizing the efficiency of the Feshbach

molecular formation. We show that the picture of two-body molecular production

depicted by the Landau-Zener model is significantly altered: The energy levels

are dramatically distorted and the conversion efficiency is suppressed by the

particle interactions. According to the rule of constant action and with the

help of phase-space analysis, we derive an analytical expression for the

conversion efficiency in the adiabatic limit. It shows a ceiling for the

conversion efficiency when the interaction strength is larger than a critical

value. We further derive a closed equation for the conversion efficiency with

the stationary phase approximation. In the sudden limit, the conversion

efficiency is twice that predicted by the two-body Landau-Zener formula. Our

analytical formula has been confirmed by numerical calculations.

\\ ( http://arxiv.org/abs/0807.1691 , 180kb)

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arXiv:0807.1580

Date: Thu, 10 Jul 2008 06:47:14 GMT (943kb)

Title: Spin squeezing in a bimodal condensate: spatial dynamics and particle

losses

Authors: Yun Li (LKB - Lhomond), Philipp Treutlein, Jakob Reichel (LKB -

Lhomond), Alice Sinatra (LKB - Lhomond)

Categories: quant-ph

Comments: 16 pages, 11 figures

\\

We propose an analytical method to study the entangled spatial and spin

dynamics of interacting bimodal Bose-Einstein condensates. We show that at

particular times during the evolution spatial and spin dynamics disentangle and

the spin squeezing can be predicted by a simple two-modes model. We calculate

the maximum spin squeezing achievable in experimentally relevant situations

with Sodium or Rubidium bimodal condensates, including the effect of the

dynamics and of one, two and three-body losses.

\\ ( http://arxiv.org/abs/0807.1580 , 943kb)

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The replacements:

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arXiv:0802.3818

replaced with revised version Fri, 4 Jul 2008 06:06:21 GMT (63kb)

Title: Dynamical Structure Factor and Spin-Density Separation for a

Weakly-Interacting Two-Component Bose Gas

Authors: M.-C. Chung and A. B. Bhattacherjee

Categories: cond-mat.other

Comments: 4 pages, 2 figures

\\ ( http://arxiv.org/abs/0802.3818 , 63kb)

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arXiv:0803.0846

replaced with revised version Fri, 4 Jul 2008 09:31:20 GMT (523kb)

Title: Ground State Properties of a Tonks-Girardeau Gas in a Split Trap

Authors: J. Goold and Th. Busch

Categories: cond-mat.other quant-ph

Comments: 7 pages, 10 figures.New Fig. 8 added and text reference to figure in

Sec IV C. New reference [15] added

Journal-ref: Phys. Rev. A 77, 063601 (2008)

\\ ( http://arxiv.org/abs/0803.0846 , 523kb)

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arXiv:0803.4158

replaced with revised version Fri, 4 Jul 2008 11:26:54 GMT (10kb)

Title: Symplectic tomography of ultracold gases in tight-waveguides

Authors: A. del Campo, V. I. Man'ko, G. Marmo

Categories: quant-ph

Comments: 5 pages, no figures

\\ ( http://arxiv.org/abs/0803.4158 , 10kb)

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arXiv:0804.2504 (*cross-listing*)

replaced with revised version Mon, 7 Jul 2008 17:27:52 GMT (212kb)

Title: Applying matrix product operators to model systems with long-range

interactions

Authors: Gregory M. Crosswhite, Andrew C. Doherty, Guifre Vidal

Categories: cond-mat.other quant-ph

Comments: 7 pages, 3 figures; manuscript has been expanded and restructured in

order to improve presentation of the algorithm

\\ ( http://arxiv.org/abs/0804.2504 , 212kb)

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arXiv:0805.3801

replaced with revised version Sat, 5 Jul 2008 15:13:19 GMT (43kb)

Title: Photo-detection using Bose-condensed atoms in a micro trap

Authors: S. Wallentowitz, A. B. Klimov

Categories: quant-ph

Comments: 11 pages, 5 figures; revised version

\\ ( http://arxiv.org/abs/0805.3801 , 43kb)

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arXiv:0804.1991

replaced with revised version Tue, 8 Jul 2008 02:49:48 GMT (107kb)

Title: Ground-state properties of interacting two-component Bose gases in a

one-dimensional harmonic trap

Authors: Yajiang Hao, Shu Chen

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

Comments: 6 pages, 5 figures, references added

\\ ( http://arxiv.org/abs/0804.1991 , 107kb)

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arXiv:0805.0798

replaced with revised version Tue, 8 Jul 2008 13:02:06 GMT (547kb)

Title: Exploring local quantum many-body relaxation by atoms in optical

superlattices

Authors: M. Cramer, A. Flesch, I.P. McCulloch, U. Schollwoeck, J. Eisert

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

Comments: 4 pages, 3 figures, version to published in Physical Review Letters

\\ ( http://arxiv.org/abs/0805.0798 , 547kb)

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arXiv:0805.3854

replaced with revised version Tue, 8 Jul 2008 00:39:49 GMT (390kb)

Title: Single Atom Detection With Optical Cavities

Authors: R. Poldy, B. C. Buchler, J. C. Close

Categories: quant-ph

Comments: 11 pages, 8 figures, submitted to PRA, minor changes in Secs. I and

IVD.2, and revised Fig.2

\\ ( http://arxiv.org/abs/0805.3854 , 390kb)

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arXiv:0711.4390

replaced with revised version Wed, 9 Jul 2008 01:22:41 GMT (385kb)

Title: Finite temperature phase diagram of a spin-polarized ultracold Fermi gas

in a highly elongated harmonic trap

Authors: Xia-Ji Liu, Hui Hu, and Peter D. Drummond

Categories: cond-mat.stat-mech

Comments: 9 pages and 8 figures; Published version in Phys. Rev. A

\\ ( http://arxiv.org/abs/0711.4390 , 385kb)

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arXiv:0712.0037

replaced with revised version Wed, 9 Jul 2008 01:44:59 GMT (150kb)

Title: Comparative study of strong coupling theories of a trapped Fermi gas at

unitarity

Authors: Hui Hu, Xia-Ji Liu, and Peter D. Drummond

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

Comments: 4 pages and 3 figures; Published version in PRA as Rapid

Communications

Journal-ref: Phys. Rev. A 77, 061605(R) (2008)

DOI: 10.1103/PhysRevA.77.061605

\\ ( http://arxiv.org/abs/0712.0037 , 150kb)

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arXiv:0801.0600

replaced with revised version Wed, 9 Jul 2008 12:19:03 GMT (817kb)

Title: State-dependent, addressable subwavelength lattices with cold atoms

Authors: W. Yi, A. J. Daley, G. Pupillo, P. Zoller

Categories: cond-mat.other

Comments: replaced with the published version. 23 pages, 11 figures

Journal-ref: New J. Phys. 10, 073015 (2008)

DOI: 10.1088/1367-2630/10/7/073015

\\ ( http://arxiv.org/abs/0801.0600 , 817kb)

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arXiv:0801.2928

replaced with revised version Wed, 9 Jul 2008 11:02:45 GMT (382kb)

Title: Cold atom dynamics in non-Abelian gauge fields

Authors: A. Jacob, P. Ohberg, G. Juzeliunas and L. Santos

Categories: cond-mat.other

Comments: 8 pages, 9 figures

Journal-ref: Appl. Phys. B 89, 439-445 (2007)

\\ ( http://arxiv.org/abs/0801.2928 , 382kb)

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arXiv:0804.3005

replaced with revised version Wed, 9 Jul 2008 08:44:11 GMT (91kb,D)

Title: Establishing EPR-channels between Nanomechanics and Atomic Ensembles

Authors: K. Hammerer, M. Aspelmeyer, E.S. Polzik, P. Zoller

Categories: quant-ph

Comments: 4 pages, 1 figure;

\\ ( http://arxiv.org/abs/0804.3005 , 91kb)

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arXiv:0712.1007

replaced with revised version Wed, 9 Jul 2008 23:20:21 GMT (802kb,D)

Title: Final-state effects in the radio frequency spectrum of strongly

interacting fermions

Authors: Sourish Basu, Erich J. Mueller

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

Comments: 4 pages, 4 figures

\\ ( http://arxiv.org/abs/0712.1007 , 802kb)

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arXiv:0803.0340

replaced with revised version Thu, 10 Jul 2008 03:23:33 GMT (467kb)

Title: Dynamical Creation of Fractionalized Vortices and Vortex Lattices

Authors: An-Chun Ji, W. M. Liu (CAS), Jun Liang Song and Fei Zhou (UBC)

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

Comments: 4 pages, 3 figures; published version

Journal-ref: Phys. Rev. Lett. 101, 010402 (2008)

\\ ( http://arxiv.org/abs/0803.0340 , 467kb)

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arXiv:0803.1167

replaced with revised version Wed, 9 Jul 2008 22:45:48 GMT (53kb)

Title: Photoassociation of a Bose-Einstein Condensate near a Feshbach Resonance

Authors: M. Junker, D. Dries, C. Welford, J. Hitchcock, Y. P. Chen and R. G.

Hulet

Categories: cond-mat.other

Comments: 4 pages, 4 figures. v2: updated comparison with theory; added

references; added tick marks to Fig. 1 inset. To be published in Phys. Rev.

Letters

\\ ( http://arxiv.org/abs/0803.1167 , 53kb)

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arXiv:0803.2574

replaced with revised version Thu, 10 Jul 2008 06:34:26 GMT (422kb)

Title: Kelvin Waves of Quantized Vortex Lines in Trapped Bose-Einstein

Condensates

Authors: T. P. Simula, T. Mizushima, and K. Machida

Categories: cond-mat.other

Comments: 4 pages, 4 figures, title changed, minor revisions

Journal-ref: Phys. Rev. Lett. 101, 020402 (2008)

DOI: 10.1103/PhysRevLett.101.020402

\\ ( http://arxiv.org/abs/0803.2574 , 422kb)

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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 Thu Aug 07 2008 - 11:07:52 EST

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