Matt's arXiv selection, Monday 27th February 2006.

From: Matthew Davis <>
Date: Mon, 27 Feb 2006 10:12:49 +1000 (EST)

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Have a good week,

Dr M. J. Davis,               Senior Lecturer in Physics
School of Physical Sciences,  email:
University of Queensland,     ph   : +61 7 334 69824
Brisbane, QLD 4072,           fax  : +61 7 336 51242
Paper (*cross-listing*): nucl-th/0602050
Date: Thu, 16 Feb 2006 20:20:01 GMT   (16kb)
Title: Density functional theory for fermions close to the unitary regime
Authors: Anirban Bhattacharyya and T. Papenbrock
Comments: 4 pages, 2 figures
Subj-class: Nuclear Theory; Strongly Correlated Electrons; Atomic Physics
  We consider interacting Fermi systems close to the unitary regime and compute
the corrections to the energy density that are due to a large scattering length
and a small effective range. Our approach exploits the universality of the
density functional and determines the corrections from the analyical results
for the harmonically trapped two-body system. The corrections due to the finite
scattering length compare well with the result of Monte Carlo simulations. We
also apply our results to symmetric neutron matter.
\\ ( ,  16kb)
Paper: cond-mat/0507460
replaced with revised version Fri, 17 Feb 2006 16:21:36 GMT   (323kb)
Title: Stability of Bosonic atomic and molecular condensates near a Feshbach
Authors: Sourish Basu, Erich J. Mueller
Comments: 4 pages, 2 figures
Subj-class: Other
\\ ( ,  323kb)
Paper: quant-ph/0602148
Date: Fri, 17 Feb 2006 11:06:03 GMT   (29kb)
Title: One-step generation of high-quality squeezed and EPR states in cavity
Authors: C. J. Villas-Boas and M. H. Y. Moussa
Journal-ref: The European Physical Journal D 32, 147 (2005)
  We show how to generate bilinear (quadratic) Hamiltonians in cavity quantum
electrodynamics (QED) through the interaction of a single driven three-level
atom with two (one) cavity modes. With this scheme it is possible to generate
one-mode mesoscopic squeezed superpositions, two-mode entanglements, and
two-mode squeezed vacuum states (such the original EPR state), without the need
for Ramsey zones and external parametric amplification. The degree of squeezing
achieved is up to 99% with currently feasible experimental parameters and the
errors due to dissipative mechanisms become practically negligible.
\\ ( ,  29kb)
Paper: quant-ph/0602149
Date: Fri, 17 Feb 2006 14:58:18 GMT   (25kb)
Title: Damped quantum harmonic oscillator
Authors: A. Isar, A. Sandulescu
Comments: 36 pages, review article
Journal-ref: Romanian J. Phys., Vol. 37, No. 7 (1992), p. 643
  In the framework of the Lindblad theory for open quantum systems the damping
of the harmonic oscillator is studied. A generalization of the fundamental
constraints on quantum mechanical diffusion coefficients which appear in the
master equation for the damped quantum oscillator is presented; the
Schr\"odinger and Heisenberg representations of the Lindblad equation are given
explicitly. On the basis of these representations it is shown that various
master equations for the damped quantum oscillator used in the literature are
particular cases of the Lindblad equation and that the majority of these
equations are not satisfying the constraints on quantum mechanical diffusion
coefficients. Analytical expressions for the first two moments of coordinate
and momentum are also obtained by using the characteristic function of the
Lindblad master equation. The master equation is transformed into Fokker-Planck
equations for quasiprobability distributions. A comparative study is made for
the Glauber $P$ representation, the antinormal ordering $Q$ representation and
the Wigner $W$ representation. It is proven that the variances for the damped
harmonic oscillator found with these representations are the same. By solving
the Fokker-Planck equations in the steady state, it is shown that the
quasiprobability distributions are two-dimensional Gaussians with widths
determined by the diffusion coefficients. The density matrix is represented via
a generating function, which is obtained by solving a time-dependent linear
partial differential equation derived from the master equation. Illustrative
examples for specific initial conditions of the density matrix are provided.
\\ ( ,  25kb)
Paper: quant-ph/0602150
Date: Fri, 17 Feb 2006 12:13:02 GMT   (356kb)
Title: Tomographic test of quantum nonlocality for a time-delocalized single
Authors: Milena D'Angelo, Alessandro Zavatta, Valentina Parigi, and Marco
Comments: 5 pages, 3 figures
  We study the nonlocal nature of a temporally-delocalized single photon by
performing the first tomographic test of Bell's inequality. Balanced homodyne
detection is performed on two well-separated temporal modes carrying a single
photon. The reconstructed two-mode Wigner function is employed to test Bell's
inequality in the form theoretically proposed by Banaszek and Wodkiewicz [1]. A
clear violation of the predictions of local hidden-variable theories is found,
provided some auxiliary assumptions are made. Our experiment is a
proof-of-principle demonstration of single-photon nonlocality, and indicates
the meaningfulness of extending the concepts of entanglement and nonlocality to
a coherently delocalized single photon. Furthermore, we show that the
tomographic approach to Bell's inequality may open the way towards completely
loophole-free tests of Bell's inequality.
\\ ( ,  356kb)
Paper: cond-mat/0602437
Date: Sat, 18 Feb 2006 08:01:00 GMT   (186kb)
Title: Phase diagrams of one-dimensional Bose-Fermi mixtures of ultra-cold
Authors: L. Mathey, D.-W. Wang
Comments: 16 pages, 8 figures
Subj-class: Other
  We study the quantum phase diagrams of Bose-Fermi mixtures of ultracold atoms
confined to one dimension in an optical lattice. For systems with
incommensurate densities, various quantum phases, e.g. charge/spin density
waves, pairing, phase separation, and the Wigner crystal, are found to be
dominant in different parameter regimes within a bosonization approach. The
structure of the phase diagram leads us to propose that the system is best
understood as a Luttinger liquid of polarons (i.e. atoms of one species
surrounded by screening clouds of the other species). Special fillings,
half-filling for fermions and unit filling for bosons, and the resulting gapped
phases are also discussed, as well as the properties of the polarons and the
experimental realization of these phases.
\\ ( ,  186kb)
Paper: cond-mat/0510624
replaced with revised version Sat, 18 Feb 2006 16:44:02 GMT   (496kb)
Title: The role of interactions, tunneling and harmonic confinement on the
  adiabatic loading of bosons in an optical lattice
Authors: Ana Maria Rey, Guido Pupillo, and J. V. Porto
Comments: 9 pages and 6 figures
Subj-class: Statistical Mechanics
Journal-ref: Phys. Rev. A 73, 023608 (2006)
\\ ( ,  496kb)
Paper: cond-mat/0511512
replaced with revised version Mon, 20 Feb 2006 12:00:14 GMT   (735kb)
Title: Tkachenko modes and structural phase transitions of the vortex lattice
  of a two component Bose-Einstein condensate
Authors: M. Keceli, M.O. Oktel
Comments: 24 pages, 13 figures, typos corrected, references added, final
Subj-class: Other
Journal-ref: Phys. Rev. A 73, 023611 (2006)
DOI: 10.1103/PhysRevA.73.023611
\\ ( ,  735kb)
Paper: cond-mat/0511641
replaced with revised version Mon, 20 Feb 2006 05:51:30 GMT   (40kb)
Title: Quantum criticality of a Fermi gas with a spherical dispersion minimum
Authors: Kun Yang and Subir Sachdev
Comments: 4 pages, 1 figure; (v2) added clarifications in response to comments
Subj-class: Strongly Correlated Electrons; Superconductivity
\\ ( ,  40kb)
Paper: quant-ph/0602163
Date: Mon, 20 Feb 2006 15:44:45 GMT   (156kb)
Title: Towards a Landau-Zener formula for an interacting Bose-Einstein
Authors: D. Witthaut, E. M. Graefe, and H. J. Korsch
Comments: RevTeX, 8 pages, 9 figures
  We consider the Landau-Zener problem for a Bose-Einstein condensate in a
linearly varying two-level system, for the full many-particle system as well
and in the mean-field approximation. The many-particle problem can be solved
approximately within an independent crossings approximation, which yields an
explicit Landau-Zener formula.
\\ ( ,  156kb)
Paper: physics/0602135
Date: Mon, 20 Feb 2006 18:36:28 GMT   (152kb)
Title: Narrow Line Photoassociation in an Optical Lattice
Authors: T. Zelevinsky, M. M. Boyd, A. D. Ludlow, T. Ido, J. Ye, R. Ciurylo, P.
  Naidon, P. S. Julienne
Comments: 4 pages, 4 figures
Subj-class: Atomic Physics; Optics
  With ultracold $^{88}$Sr in a 1D magic wavelength optical lattice, we
performed narrow line photoassociation spectroscopy near the $^1$S$_0 -
^3$P$_1$ intercombination transition. Nine least-bound vibrational molecular
levels associated with the long-range $0_u$ and $1_u$ potential energy surfaces
were measured and identified. A simple theoretical model accurately describes
the level positions and treats the effects of the lattice confinement on the
line shapes. The measured resonance strengths show that optical tuning of the
ground state scattering length should be possible without significant atom
\\ ( ,  152kb)
Paper: physics/0512184
replaced with revised version Mon, 20 Feb 2006 09:04:47 GMT   (132kb)
Title: Coupled atomic-molecular condensates in a double-well potential:
  decaying molecular oscillations
Authors: Hui Jing, Sihong Gu and Mingsheng Zhan
Comments: 6 pages, 4 figures, submitted
Subj-class: Atomic Physics
\\ ( ,  132kb)
Paper: cond-mat/0602468
Date: Mon, 20 Feb 2006 22:35:46 GMT   (444kb)
Title: Three-body local correlation function in the Lieb-Liniger model:
  bosonization approach
Authors: Vadim V. Cheianov, H. Smith, M. B. Zvonarev
Comments: 40 pages, 2 figures
Subj-class: Other
  We develop a method for the calculation of vacuum expectation values of local
operators in the Lieb-Liniger model. This method is based on a set of new
identities obtained using integrability and effective theory (``bosonization'')
description. We use this method to get an explicit expression for the
three-body local correlation function, measured in a recent experiment [1].
\\ ( ,  444kb)
Paper: cond-mat/0602475
Date: Tue, 21 Feb 2006 01:17:25 GMT   (63kb)
Title: Full counting statistics of interference experiments between interacting
  one dimensional Bose liquids
Authors: Vladimir Gritsev, Ehud Altman, Eugene Demler, Anatoli Polkovnikov
Comments: 5 pages, 4 figures
Subj-class: Strongly Correlated Electrons; Mesoscopic Systems and Quantum Hall
  We analyze the full counting statistics of the amplitude of interference
fringes for bosons released from two independent one dimensional condensates at
zero temperature. We show that the distribution function of fringe amplitudes
is related to the partition function for a quantum impurity in a
one-dimensional Luttinger liquid and can be calculated explicitly using methods
of conformal field theory. We point out interesting relations between these
distribution functions and transfer matrices of conformal field theories. This
establishes a connection between BEC interference experiments and a variety of
statistical models ranging from stochastic growth models to two dimensional
quantum gravity.
\\ ( ,  63kb)
Paper: cond-mat/0602483
Date: Tue, 21 Feb 2006 09:58:17 GMT   (79kb)
Title: Exact ground state properties of finite ultracold Bose gases in a
  hard-wall trap
Authors: Yajiang Hao, Yunbo Zhang, J.-Q. Liang and Shu Chen
Comments: 5 pages, 5 figures
Subj-class: Strongly Correlated Electrons
  We investigate the ground state of the system of $N$ bosons enclosed in a
hard-wall trap interacting via a repulsive or attractive $\delta $ -function
potential. Based on the Bethe ansatz method, the explicit wave function is
derived and is decided by numerically solving the Bethe ansatz equations for
the full physical regimes ($-\infty <c<+\infty $). The ground state density
profiles for finite systems with both the repulsive and attractive interactions
are obtained by evaluating the one body density matrix.
\\ ( ,  79kb)
Paper: cond-mat/0504612
replaced with revised version Tue, 21 Feb 2006 13:14:01 GMT   (531kb)
Title: Formation of a vortex lattice in a rotating BCS Fermi gas
Authors: Giulia Tonini (INFN), F\'{e}lix Werner (LKB - Lhomond), Yvan Castin
  (LKB - Lhomond)
Comments: 14 pages
Proxy: ccsd ccsd-00004798
Subj-class: Other
\\ ( ,  531kb)
Paper: cond-mat/0602245
replaced with revised version Tue, 21 Feb 2006 03:42:45 GMT   (65kb)
Title: Competing Orders in two-dimensional Bose-Fermi mixtures
Authors: L. Mathey, S-W. Tsai, A.H. Castro Neto
Comments: 4 pages, 3 figures, minor corrections
Subj-class: Other
\\ ( ,  65kb)
Paper: quant-ph/0602170
Date: Tue, 21 Feb 2006 04:40:16 GMT   (373kb)
Title: Low-lying bifurcations in cavity quantum electrodynamics
Authors: Michael A. Armen and Hideo Mabuchi
Comments: 13 pages, 10 figures, submitted to PRA
  The interplay of quantum fluctuations with nonlinear dynamics is a central
topic in the study of open quantum systems, connected to fundamental issues
(such as decoherence and the quantum-classical transition) and practical
applications (such as coherent information processing and the development of
mesoscopic sensors/amplifiers). With this context in mind, we here present a
computational study of some elementary bifurcations that occur in a driven and
damped cavity quantum electrodynamics (cavity QED) model at low intracavity
photon number. In particular, we utilize the single-atom cavity QED Master
Equation and associated Stochastic Schrodinger Equations to characterize the
equilibrium distribution and dynamical behavior of the quantized intracavity
optical field in parameter regimes near points in the semiclassical
(mean-field, Maxwell-Bloch) bifurcation set. Our numerical results show that
the semiclassical limit sets are qualitatively preserved in the quantum
stationary states, although quantum fluctuations apparently induce phase
diffusion within periodic orbits and stochastic transitions between attractors.
We restrict our attention to an experimentally realistic parameter regime.
\\ ( ,  373kb)
Paper: cond-mat/0602504
Date: Tue, 21 Feb 2006 21:01:27 GMT   (150kb)
Title: Disorder-enhanced phase coherence in trapped bosons on optical lattices
Authors: Pinaki Sengupta, Aditya Raghavan, Stephan Haas
Comments: 4 pages, 4 figures
Subj-class: Other
  The consequences of disorder on interacting bosons trapped in optical
lattices are investigated by quantum Monte Carlo simulations. At small to
moderate strengths of potential disorder a unique effect is observed: if there
is a Mott plateau at the center of the trap in the clean limit, phase coherence
{\it increases} as a result of disorder. The localization effects due to
correlation and disorder compete against each other, resulting in a partial
delocalization of the particles in the Mott region, which in turn leads to
increased phase coherence. In the absence of a Mott plateau, this effect is
absent. A detailed analysis of the uniform system without a trap shows that the
disordered states participate in a Bose glass phase.
\\ ( ,  150kb)
Paper: cond-mat/0602525
Date: Wed, 22 Feb 2006 20:12:11 GMT   (429kb)
Title: Superfluid phases of the three-species fermion gas
Authors: Paulo F. Bedaque, Jos\'e P. D'Incao
Comments: 4 pages, 1 figure
Subj-class: Other
  We discuss the zero temperature phase diagram of a dilute gas with three
fermionic species. We make use of solvable limits to conjecture the behavior of
the system in the ``unitary'' regions. The physics of the Thomas-Efimov effect
plays a role in these considerations. We find a rich phase diagram with
superfluid, gapless superfluid and inhomogeneous phases with different symmetry
breaking patterns. We then discuss one particular possible experimental
implementation in a system of ^6Li atoms and the possible phases arising in
this system as an external magnetic field is varied across three overlaping
Feshbach resonances. We also suggest how to experimentally distinguish the
different phases.
\\ ( ,  429kb)
Paper: quant-ph/0602180
Date: Wed, 22 Feb 2006 13:41:06 GMT   (12kb)
Title: Single phonon detection scheme in dilute Bose-Einstein condensates
Authors: Ralf Sch\"utzhold
Comments: 4 pages
  Based on doubly detuned Raman transitions between (meta) stable hyperfine
states and recently developed atom counting techniques, a detection scheme for
sound waves in dilute Bose-Einstein condensates with an accuracy down to the
single-phonon level is proposed. This scheme would open up a new range of
applications including the experimental observation of quantum radiation
phenomena such as the Hawking effect in sonic black-hole analogues. PACS:
03.75.Kk, 04.70.Dy, 42.65.Dr.
\\ ( ,  12kb)
Paper: cond-mat/0602549
Date: Thu, 23 Feb 2006 12:54:47 GMT   (28kb)
Title: The four-boson scale near a Feshbach resonance
Authors: M. T. Yamashita, Lauro Tomio, A. Delfino and T. Frederico
Comments: 4 pages, 1 figure
Subj-class: Soft Condensed Matter
  We show that an independent four-body momentum scale $\mu_{(4)}$ drives the
tetramer binding energy for fixed trimer energy (or three-body scale
$\mu_{(3)}$) and large scattering length ($a$). The three- and four-body forces
from the one-channel reduction of the atomic interaction near a Feshbach
resonance disentangle $\mu_{(4)}$ and $\mu_{(3)}$. The four-body independent
scale is also manifested through a family of Tjon-lines, with slope given by
$\mu_{(4)}/\mu_{(3)}$ for $a^{-1}=0$. A new renormalization group limit cycle
is expected to appear due to the new scale.
\\ ( ,  28kb)
Paper: cond-mat/0602568
Date: Thu, 23 Feb 2006 20:34:17 GMT   (291kb)
Title: Homogeneous Fermion Superfluid with Unequal Spin Populations
Authors: Tin-Lun Ho and Hui Zhai
Comments: 4 pages, 3 figures
Subj-class: Superconductivity
  For decades, the conventional view is that an s-wave BCS superfluid can not
support uniform spin polarization due to a gap $\Delta$ in the quasiparticle
excitation spectrum. We show that this is an artifact of the dismissal of
quasiparticle interactions $V_{qp}^{}$ in the conventional approach at the
outset. Such interactions can cause triplet fluctuations in the ground state
and hence non-zero spin polarization at "magnetic field" $h<\Delta$. The
resulting ground state is a pairing state of quasiparticles on the ``BCS
vacuum". For sufficiently large $V_{qp}$, the spin polarization of at unitarity
has the simple form $m\propto \mu^{1/2}$. Our study is motivated by the recent
experiments at Rice which found evidence of a homogenous superfluid state with
uniform spin polarization.
\\ ( ,  291kb)
Paper: cond-mat/0601650
replaced with revised version Thu, 23 Feb 2006 16:08:23 GMT   (34kb)
Title: Dynamics of the Bose-Hubbard model: transition from Mott insulator to
Authors: Fernando M. Cucchietti, Bogdan Damski, Jacek Dziarmaga, and Wojciech
  H. Zurek
Comments: 4 pages & 3 figures, some improvements in presentation with respect
  to former version
Report-no: LAUR-06-0477
Subj-class: Other
\\ ( ,  34kb)
Received on Mon Feb 27 2006 - 10:12:49 EST

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