Matt's arXiv selection: week ending 27 March 2009

From: Matthew Davis <>
Date: Wed, 20 May 2009 16:57:50 +1000

The following message was sent to the matts_arxiv list by Matthew Davis <>

Dear subscribers,

Simon Haine deserves the credit for preparing this email. There are 14 new
preprints and 4 replacements:

Date: Fri, 20 Mar 2009 15:47:13 GMT (405kb)

Title: Cavity QED in a molecular ion trap
Authors: D. I. Schuster, Lev S. Bishop, I. L. Chuang, D. DeMille, R. J.
Categories: cond-mat.mes-hall cond-mat.supr-con quant-ph
Comments: 4 pages, 1 figure
  We propose an approach for studying quantum information and performing high
resolution spectroscopy of rotational states of trapped molecular ions using an
on-chip superconducting microwave resonator. Molecular ions have several
advantages over neutral molecules. Ions can be loaded into deep (1 eV) RF traps
and are trapped independent of the electric dipole moment of their rotational
transition. Their charge protects them from motional dephasing and prevents
collisional loss, allowing 1 s coherence times when used as a quantum memory,
with detection of single molecules possible in <10 ms. An analysis of the
detection efficiency and coherence properties of the molecules is presented.
\\ ( , 405kb)
Date: Fri, 20 Mar 2009 13:40:11 GMT (178kb)

Title: Autler-Townes effect in the D1-line hyperfine structure of an alkali
Authors: A.S.Sheremet, O.S.Mishina, N.V.Larionov, D.V.Kupriyanov
Categories: quant-ph
Comments: 12 pages, 5 figures
  We consider the Autler-Townes effect when a strong coupling field is applied
in the hyperfine manifold of an alkali atom. Explicit solution is obtained in
the case of the D1-line. We show how the hyperfine interaction modifies the
dressing effects associated with the strong field as well as the sample
susceptibility with respect to the probe mode. Particularly, if the strong
field is far detuned from the atomic resonance line the Autler-Townes structure
differs significantly from the prediction of the Lambda-type approximation. We
also find that tuning the strong field in between the upper state hyperfine
components enhances the Autler-Townes effect. The results are discussed in the
context of quantum memory protocols based on the stimulated Raman process or
EIT effect.
\\ ( , 178kb)
Date: Fri, 20 Mar 2009 19:53:54 GMT (450kb)

Title: Large Momentum Beamsplitter using Bloch Oscillations
Authors: Pierre Clad\'e (LKB - Jussieu), Sa\"ida Guellati-Kh\'elifa (LKB -
  Jussieu), Fran\c{c}ois Nez (LKB - Jussieu), Fran\c{c}ois Biraben (LKB -
Categories: physics.atom-ph
  The sensitivity of an inertial sensor based on an atomic interfermometer is
proportional to the velocity separation of atoms in the two arms of the
interferometer. In this paper we describe how Bloch oscillations can be used to
increase this separation and to create a large momentum transfer (LMT)
beamsplitter. We experimentally demonstrate a separation of 10 recoil
velocities. Light shifts during the acceleration introduce phase fluctuations
which can reduce the contrast of the interferometer. We precisely calculate
this effect and demonstrate that it can be significantly reduced by using a
suitable combination of LMT pulses. We finally show that this method seems to
be very promising to realize LMT beamsplitter with several 10s of recoil and a
very good efficiency.
\\ ( , 450kb)
Date: Thu, 19 Mar 2009 21:41:23 GMT (87kb)

Title: How Marius Was Right and Galileo Was Wrong Even Though Galileo Was Right
  and Marius Was Wrong
Authors: Christopher M. Graney
Categories: physics.hist-ph
Comments: Or, how telescopic observations in the early 17th century supported
  the Tychonic geocentric theory and how Simon Marius realized this
  Astronomers in the early 17th century misunderstood the images of stars that
they saw in their telescopes. For this reason, the data a skilled observer of
that time acquired via telescopic observation of the heavens appeared to
support a geocentric Tychonic (or semi-Tychonic) world system, and not a
heliocentric Copernican world system. Galileo Galilei made steps in the
direction of letting observations lead him towards a Tychonic or semi-Tychonic
world system. However, he ultimately backed the Copernican system, against the
data he had on hand. By contrast, the German astronomer Simon Marius understood
that data acquired by telescopic observation supported a Tychonic world system.
\\ ( , 87kb)
Date: Mon, 23 Mar 2009 13:43:17 GMT (110kb)

Title: Nonlinear dynamics of ultracold gases in double-well lattices
Authors: V.I. Yukalov and E.P. Yukalova
Categories: cond-mat.stat-mech cond-mat.other
Comments: Latex file, 15 pages, 3 figures
Journal-ref: Laser Phys. Lett. 6 (2009) 235-241
  An ultracold gas is considered, loaded into a lattice, each site of which is
formed by a double-well potential. Initial conditions, after the loading,
correspond to a nonequilibrium state. The nonlinear dynamics of the system,
starting with a nonequilibrium state, is analysed in the local-field
approximation. The importance of taking into account attenuation, caused by
particle collisions, is emphasized. The presence of this attenuation
dramatically influences the system dynamics.
\\ ( , 110kb)
Date: Mon, 23 Mar 2009 14:37:15 GMT (14kb)

Title: Absence of a Direct Superfluid to Mott Insulator Transition in
  Disordered Bose Systems
Authors: L. Pollet, N.V. Prokof'ev, B. V. Svistunov, M. Troyer
Categories: cond-mat.stat-mech cond-mat.other
Comments: 4 pages, 3 figures
  We present a rigorous analytic proof of the absence of a direct quantum phase
transition between a superfluid and a Mott insulator in a commensurate bosonic
system with generic bounded disorder. The theorem is illustrated by quantum
Monte Carlo simulations for the Bose-Hubbard model, from which we deduce an
even stronger result: The critical disorder strength, $\Delta_c$, corresponding
to the onset of disorder-induced superfluidity, satisfies the relation
$\Delta_c > E_{\rm g/2}$, with $E_{\rm g/2}$ the half-width of the Mott gap in
the pure system.
\\ ( , 14kb)
Date: Mon, 23 Mar 2009 16:22:08 GMT (926kb)

Title: An integrated atom detector: single atoms and photon statistics
Authors: Dennis Heine, Marco Wilzbach, Thomas Raub, Bj\"orn Hessmo, and J\"org
Categories: quant-ph
Comments: 4 pages, 4 figures
Journal-ref: Phys. Rev. A 79, 021804 (2009)
DOI: 10.1103/PhysRevA.79.021804
  We demonstrate a robust fiber-optics-based fluorescence detector, fully
integrated on an atom chip, which detects single atoms propagating in a guide
with 66% efficiency. We characterize the detector performance and the atom flux
by analyzing the photon statistics. Near-perfect photon antibunching proves
that single atoms are detected, and allows us to study the second-order
intensity correlation function of the fluorescence over three orders of
magnitude in atomic density.
\\ ( , 926kb)
Date: Mon, 23 Mar 2009 07:13:58 GMT (22kb)
Title: Dynamics of Cold Atoms Crossing a One-Way Barrier
Authors: Jeremy J. Thorn, Elizabeth A. Schoene, Tao Li, and Daniel A. Steck
Categories: physics.atom-ph
Comments: 20 pages, 19 figures
  We implemented an optical one-way potential barrier that allows ultracold
$^{87}$Rb atoms to transmit through when incident on one side of the barrier
but reflect from the other. This asymmetric barrier is a realization of
Maxwell's demon, which can be employed to produce phase-space compression and
has implications for cooling atoms and molecules not amenable to standard
laser-cooling techniques. The barrier comprises two focused, Gaussian laser
beams that intersect the focus of a far-off-resonant, single-beam optical
dipole trap that holds the atoms. The main barrier beam presents a
state-dependent potential to incident atoms, while the repumping barrier beam
optically pumps atoms to a trapped state. We investigated the robustness of the
barrier asymmetry to changes in the barrier beam separation, the initial atomic
potential energy, the intensity of the second beam, and the detuning of the
first beam. We performed simulations of the atomic dynamics in the presence of
the barrier, showing that the initial three dimensional momentum distribution
plays a significant role, and that light-assisted collisions are likely the
dominant loss mechanism. We also carefully examined the relationship to
Maxwell's demon and explicitly accounted for the apparent decrease in entropy
for our particular system.
\\ ( , 1607kb)
Date: Tue, 24 Mar 2009 13:46:08 GMT (55kb)

Title: Wannier-function approach to the Interaction Effects in a Bose-Einstein
  Condensate on an Optical Lattice: Implications for the Bose-Hubbard Model
Authors: Z. X. Liang, B. B. Hu, and Biao Wu
Categories: cond-mat.str-el
Comments: 4 pages, 3 figures
  We show that one can properly take into account of the interaction effects
and construct a set of orthonormal Wannier functions for a Bose-Einstein
condensate in an optical lattice. These interaction-dependent Wannier functions
are used to compute the tunneling rate $J$ and the on-site repulsion $U$ in the
Bose-Hubbard model. Both parameters are found to be substantially different
from ones calculated with the single-particle Wannier functions. Our numerical
results of $U$ are found in good agreement with the measured on-site energy in
a recent experiment [Campbell {\it et al.} Science {\bf 314}, 281 (2006)].
\\ ( , 55kb)
Date: ?? (??kb)

Title: Correlation Measurement of Squeezed Light
Authors: Leonid A. Krivitsky, Ulrik L. Andersen, Ruifang Dong, Alexander Huck,
  Christoffer Wittmann, and Gerd Leuchs
Categories: quant-ph
Journal-ref: Phys. Rev. A 79, 033828 (2009)
  We study the implementation of a correlation measurement technique for the
characterization of squeezed light which is nearly free of electronic noise.
With two different sources of squeezed light, we show that the sign of the
covariance coefficient, revealed from the time resolved correlation data, is
witnessing the presence of squeezing in the system. Furthermore, we estimate
the degree of squeezing using the correlation method and compare it to the
standard homodyne measurement scheme. We show that the role of electronic
detector noise is minimized using the correlation approach as opposed to
homodyning where it often becomes a crucial issue.
\\ ( , 294kb)
Date: Wed, 25 Mar 2009 04:39:04 GMT (138kb)

Title: Cold-atoms on a two-dimensional square optical lattice with an
  alternating potential
Authors: Huaiming Guo, Yuchuan Wen, and Shiping Feng
Categories: cond-mat.str-el
Comments: 4 pages, 4 figures
Journal-ref: Physical Review A 79,035401(2009)
DOI: 10.1103/PhysRevA.79.035401
  The cold-atom on a two-dimensional square optical lattice is studied within
the hard-core boson Hubbard model with an alternating potential. In terms of
the quantum Monte Carlo method, it is shown explicitly that a supersolid phase
emerges due to the presence of the alternating potential. For the weak
alternating potential, the supersolid state appears for the whole range of
hard-core boson densities except the half-filling case, where the system is a
Mott insulator. However, for the strong alternating potential, besides the
supersolid and Mott insulating states, a charge density wave phase appears.
\\ ( , 138kb)
Date: Tue, 24 Mar 2009 20:46:47 GMT (625kb)

Title: Atom interferometers with scalable enclosed area
Authors: Holger Mueller, Sheng-wey Chiow, Sven Herrmann, and Steven Chu
Categories: physics.atom-ph cond-mat.other physics.optics
Comments: 4 pages, 5 figures
  Bloch oscillations (i.e., coherent acceleration of matter waves by an optical
lattice) and Bragg diffraction are integrated into light-pulse atom
interferometers with large momentum splitting between the interferometer arms,
and hence enhanced sensitivity. Simultaneous acceleration of both arms in the
same internal states suppresses systematic effects, and simultaneously running
a pair of interferometers suppresses the effect of vibrations. Ramsey-Bord\'e
interferometers using four such Bloch-Bragg-Bloch (BBB) beam splitters exhibit
15% contrast at 24$\hbar k$ splitting, the largest so far ($\hbar k$ is the
photon momentum); single beam splitters achieve 88$\hbar k$. The prospects for
reaching 100s of $\hbar k$ and applications like gravitational wave sensors are
\\ ( , 625kb)
Date: Thu, 26 Mar 2009 11:32:01 GMT (165kb)

Title: An equation of state for low and high energy Bose-Einstein condensation
Authors: Vito Barbarani
Categories: cond-mat.other
Comments: 20 pages, 9 figures. An extended abstract of this work was accepted
  for poster contribution at the 22nd General Conference of the Condensed
  Matter Division of the European Physical Society (CMD22, August 25th-29th,
  2008, Rome)
  The aim of this work is to investigate how energy depends on the two-body
interaction potential in Bose-Einstein condensation (BEC) phenomena. An
equation of state is obtained which is valid both for low and high energy BEC,
through the application of a revised form of quantum statistics. An extension
of the singularity conditions describing the state of BEC is given, in order to
consider interactions between particles due to a central interatomic potential.
  From the singularity conditions of the corresponding system of hard-sphere
bosons and the equation for the energy of the system in its ground state, the
equation of state connecting temperature, density and energy in BEC is deduced,
with upper and lower limits for the energy depending on the form of the central
interaction potential. It is shown that high energy mode is allowed in the case
of Coulomb type interaction only, low energy mode in the case of non-Coulomb
type interaction. Numerical results are then derived for low energy BEC,
occurring in neutral matter, with application to He-4 and alkali-metal atoms,
and in the case of high energy BEC occurring in systems of charged bosons, with
application to atomic nuclei.
\\ ( , 165kb)
Date: Thu, 26 Mar 2009 18:59:25 GMT (361kb)

Title: A single structured light beam as an atomic beam splitter
Authors: B. M. Rodriguez-Lara and R. Jauregui
Categories: quant-ph physics.atom-ph
Comments: 10 pages, 5 figures
  We propose a scheme to split a cloud of cold non-interacting neutral atoms
based on their dipole interaction with a single structured light beam which
exhibits parabolic cylindrical symmetry. Using semiclassical numerical
simulations, we establish a direct relationship between the general properties
of the light beam and the geometric and kinematic properties acquired by the
atomic cloud as its passes through the beam.
\\ ( , 361kb)

The replacements:

replaced with revised version Mon, 23 Mar 2009 00:47:51 GMT (342kb)

Title: Atom-Pair Tunneling and Quantum Phase Transition in Strong Interaction
Authors: J.-Q. Liang, J.-L. Liu, W.-D. Li, Z.-J. Li
Categories: cond-mat.other quant-ph
Comments: 6 figures
Journal-ref: Phys. Rev. A 79(3), 033617 (2009) [8 pages]
\\ ( , 342kb)
replaced with revised version Mon, 23 Mar 2009 21:03:30 GMT (54kb)

Title: Spin squeezing and entanglement
Authors: Geza Toth, Christian Knapp, Otfried G\"uhne, Hans J. Briegel
Categories: quant-ph cond-mat.other cond-mat.stat-mech
Comments: 13 pages including 6 figures and 2 tables, revtex4; v2: changes
  before publication in Phys. Rev. A
\\ ( , 54kb)
replaced with revised version Thu, 26 Mar 2009 01:21:26 GMT (24kb)

Title: Fractional Spin Hall Effect in Atomic Bose Gases
Authors: Xiong-Jun Liu, Xin Liu, L. C. Kwek and C. H. Oh
Categories: cond-mat.mes-hall quant-ph
Comments: 8 pages, 2 figures, to appear in Phys. Rev. B
\\ ( , 24kb)
replaced with revised version Thu, 26 Mar 2009 07:48:06 GMT (442kb,D)

Title: Quasi-condensation and coherence in the quasi-two-dimensional trapped
  Bose gas
Authors: R.N. Bisset, M.J. Davis, T.P. Simula, and P.B. Blakie
Categories: cond-mat.other
Comments: 9 pages, 7 figures
\\ ( , 442kb)

Till next time,

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,        
Matt's arXiv selection: weekly summary of cold-atom papers from
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Received on Thu May 21 2009 - 15:50:53 EST

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