[Matts-arxiv] Matt's arXiv selection: week ending 7 August 2009 from Matthew Davis on 2009-09-11 (Matt's arXiv selection)

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

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/
=========================================================================
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Received on Thu Sep 24 2009 - 15:47:36 EST

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