# Matt's arXiv selection: week ending 11 July 2008

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
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
\\
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
\\
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/
=========================================================================
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Received on Thu Aug 07 2008 - 11:07:52 EST

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