# Matt's arXiv selection, Tuesday 27th June 2006.

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Tue, 27 Jun 2006 15:09:29 +1000 (EST)

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

Another week, and another day late - sorry yet again. Today's message includes
the Tuesday arXiv mailing.

Interesting looking papers this week include two papers on imaging Mott
Insulator shells in a harmonic trap: one each from the groups of Bloch and
Ketterle. Also a paper introducing "Atomtronics" out of the group of Murray
Holland.

The abstracts:

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Paper: cond-mat/0606470
Date: Sun, 18 Jun 2006 03:09:45 GMT (48kb)

Title: Superconductivity on the honeycomb lattice: Semimetal-to-superconductor
transition and BCS-BEC crossover
Authors: Erhai Zhao, Arun Paramekanti (University of Toronto)
Subj-class: Superconductivity; Strongly Correlated Electrons
\\
We study the attractive Hubbard model on the two-dimensional honeycomb
lattice, focusing on the semimetal-to-superconductor transition at half-filling
(at a critical $U_c$) and the BCS-to-BEC crossover for small deviations from
half-filling. At a small density deviation $\delta n$ from half-filling, we
show that although the underlying metallic state has a small Fermi surface and
a small effective Fermi energy $\sim v_F \sqrt{\delta n}$, the BCS-to-BEC
crossover is very different from a dilute gas of fermions in that it occurs at
an interaction strength $U \gg v_F \sqrt{\delta n}$. Rather, the crossover and
the maximum SC transition occur at $U \sim U_c$, and thus lie close to the
quantum critical point at half-filling. We compute the SC collective modes
spectra in the crossover regime and show that an undamped Leggett mode emerges
deep in the BEC regime in addition to the Goldstone sound mode. In the
semimetal phase, the long wavelength SC fluctuations are critically damped by
the gapless Dirac fermions while short wavelength fluctuations can propagate as
weakly damped excitations.
\\ ( http://arXiv.org/abs/cond-mat/0606470 , 48kb)
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Paper: cond-mat/0606471
Date: Sun, 18 Jun 2006 06:45:43 GMT (42kb)

Title: Studies of bosons in optical lattices in a harmonic potential
Authors: R. Ramakumar, A. N. Das, and S. Sil
Subj-class: Statistical Mechanics; Other
\\
We present a theoretical study of bose condensation and specific heat of
non-interacting bosons in finite lattices in harmonic potentials in one, two,
and three dimensions. We numerically diagonalize the Hamiltonian to obtain the
energy levels of the systems. Using the energy levels thus obtained, we
investigate the temperature dependence, dimensionality effects, lattice size
dependence, and evolution to the bulk limit of the condensate fraction and the
specific heat. The results obtained are contextualized within the current
experimental and theoretical scenario.
\\ ( http://arXiv.org/abs/cond-mat/0606471 , 42kb)
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Paper: cond-mat/0606484
Date: Mon, 19 Jun 2006 10:10:06 GMT (45kb)

Title: Gapless Hartree-Fock-Bogoliubov Approximation for Bose Gases
Authors: V.I. Yukalov and H. Kleinert
Comments: Latex file, 22 pages, 2 figures
Subj-class: Statistical Mechanics
Journal-ref: Phys. Rev. A 73 (2006) 063612-9
\\
A dilute Bose system with Bose-Einstein condensate is considered. It is shown
that the Hartree-Fock-Bogolubov approximation can be made both conserving as
well as gapless. This is achieved by taking into account all physical
normalization conditions, that is, the normalization condition for the
condensed particles and that for the total number of particles. Two Lagrange
multipliers, introduced for preserving these normalization conditions, make the
consideration completely self-consistent.
\\ ( http://arXiv.org/abs/cond-mat/0606484 , 45kb)
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Paper: cond-mat/0606490
Date: Mon, 19 Jun 2006 15:27:24 GMT (205kb)

Title: Spin Diffusion in Trapped Gases: Anisotropy in Dipole and Quadrupole
Modes
Authors: W. J. Mullin, R. J. Ragan
Subj-class: Other; Statistical Mechanics
\\
Recent experiments in a mixture of two hyperfine states of trapped Bose gases
show behavior analogous to a spin-1/2 system, including transverse spin waves
and other familiar Leggett-Rice-type effects. We have derived the kinetic
equations applicable to these systems, including the spin dependence of
interparticle interactions in the collision integral, and have solved for
spin-wave frequencies and longitudinal and transverse diffusion constants in
the Boltzmann limit. We find that, while the transverse and longitudinal
collision times for trapped Fermi gases are identical, the Bose gas shows
unusual diffusion anisotropy in both dipole and quadrupole modes. Moreover, the
lack of spin isotropy in the interactions leads to the non-conservation of
transverse spin, which in turn has novel effects on the hydrodynamic modes.
\\ ( http://arXiv.org/abs/cond-mat/0606490 , 205kb)
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Paper (*cross-listing*): nucl-th/0606019
Date: Tue, 13 Jun 2006 18:05:41 GMT (124kb)

Title: From Trapped Atoms to Liberated Quarks
Authors: Thomas Schaefer (North Carolina State University)
Comments: 13 pages, 5 figures; to appear in the proceedings of the
International Symposium on Heavy Ion Physics 2006, Frankfurt, Germany;
International Journal of Modern Physics E, in press
Subj-class: Nuclear Theory; Superconductivity
\\
We discuss some aspects of cold atomic gases in the unitarity limit that are
of interest in connection with the physics of dense hadronic matter. We
consider, in particular, the equation of state at zero temperature, the
magnitude of the pairing gap, and the phase diagram at non-zero polarization.
\\ ( http://arXiv.org/abs/nucl-th/0606019 , 124kb)
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Paper: cond-mat/0603404
replaced with revised version Sat, 17 Jun 2006 19:17:24 GMT (119kb)

Title: Dynamical vanishing of the order parameter in a fermionic condensate
Authors: Emil A. Yuzbashyan and Maxim Dzero
Comments: 4 pages, 3 figures, journal version
Subj-class: Superconductivity; Other
Journal-ref: Phys. Rev. Lett. 96, 230404 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0603404 , 119kb)
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Paper: cond-mat/0602483
replaced with revised version Mon, 19 Jun 2006 00:39:38 GMT (85kb)

Title: Ground-state properties of one-dimensional ultracold Bose gases in a
hard-wall trap
Authors: Yajiang Hao, Yunbo Zhang, J.-Q. Liang and Shu Chen
Comments: 7 pages, 6 figures, version published in Phys. Rev. A
Subj-class: Strongly Correlated Electrons
Journal-ref: Phys. Rev. A 73, 063617 (2006)
\\ ( http://arXiv.org/abs/cond-mat/0602483 , 85kb)
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Paper: cond-mat/0604673
replaced with revised version Mon, 19 Jun 2006 16:02:46 GMT (127kb)

Title: Evolution from a Bose-Einstein Condensate to a Tonks-Girardeau Gas: An
Exact Diagonalization Study
Authors: Frank Deuretzbacher, Kai Bongs, Klaus Sengstock, Daniela Pfannkuche
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0604673 , 127kb)
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Paper: quant-ph/0606145
Date: Sun, 18 Jun 2006 12:55:40 GMT (607kb)

Title: Atom Lithography with Near-Resonant Light Masks: Quantum Optimization
Analysis
Authors: R. Arun, Offir Cohen, and I.Sh. Averbukh
Comments: 10 pages including 11 figures in Revtex
\\
We study the optimal focusing of two-level atoms with a near resonant
standing wave light, using both classical and quantum treatments of the
problem. Operation of the focusing setup is considered as a nonlinear spatial
squeezing of atoms in the thin- and thick-lens regimes. It is found that the
near-resonant standing wave focuses the atoms with a reduced background in
comparison with far-detuned light fields. For some parameters, the quantum
atomic distribution shows even better localization than the classical one.
Spontaneous emission effects are included via the technique of quantum Monte
Carlo wave function simulations. We investigate the extent to which
non-adiabatic and spontaneous emission effects limit the achievable minimal
size of the deposited structures.
\\ ( http://arXiv.org/abs/quant-ph/0606145 , 607kb)
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Paper: quant-ph/0606147
Date: Mon, 19 Jun 2006 17:23:05 GMT (655kb)

Title: Theory for a Hanbury Brown Twiss experiment with a pulsed atomic beam
Authors: Jose Viana Gomes (LCFIO), Aur\'{e}lien Perrin (LCFIO), Martijn
Schellekens (LCFIO), Denis Boiron (LCFIO), Christoph I. Westbrook (LCFIO),
Michael Belsley
Proxy: ccsd ccsd-00080649
\\
We have studied one-body and two-body correlation functions in a
ballistically expanding, non-interacting atomic cloud in the presence of
gravity. We find that the correlation functions are equivalent to those at
thermal equilibrium in the trap with an appropriate rescaling of the
coordinates. We derive simple expressions for the correlation lengths and give
some physical interpretations. Finally a simple model to take into account
finite detector resolution is discussed.
\\ ( http://arXiv.org/abs/quant-ph/0606147 , 655kb)
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Paper: quant-ph/0606155
Date: Mon, 19 Jun 2006 15:25:49 GMT (100kb)

Title: Coherent control of collective spontaneous emission in an extended
atomic ensemble and quantum storage
Authors: Alexey Kalachev, Stefan Kroll
Comments: 11 pages, 4 figures, submitted to PRA
\\
Coherent control of collective spontaneous emission in an extended atomic
ensemble resonantly interacting with single-photon wave packets is analyzed. A
scheme for coherent manipulation of collective atomic states is developed such
that superradiant states of the atomic system can be converted into subradiant
ones and vice versa. Possible applications of such a scheme for optical quantum
state storage and single-photon wave packet shaping are discussed. It is shown
that also in the absence of inhomogeneous broadening of the resonant line,
single-photon wave packets with arbitrary pulse shape may be recorded as a
subradiant state and reconstructed even although the duration of the wave
packets is larger than the superradiant life-time. Specifically the
applicability for storing time-bin qubits, which are used in quantum
cryptography is analyzed.
\\ ( http://arXiv.org/abs/quant-ph/0606155 , 100kb)
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Paper: quant-ph/0603016
replaced with revised version Mon, 19 Jun 2006 13:15:31 GMT (249kb)

Title: Quantum correlations of two optical fields close to electromagnetically
induced transparency
Authors: Alice Sinatra (LKB - Lhomond)
Proxy: ccsd ccsd-00019947
\\ ( http://arXiv.org/abs/quant-ph/0603016 , 249kb)
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Paper: physics/0606165
Date: Mon, 19 Jun 2006 07:16:39 GMT (822kb)

potentials
Authors: I. Lesanovsky, S.Hofferberth, J.Schmiedmayer, and P. Schmelcher
Subj-class: Atomic Physics
\\
We explore properties of atoms whose magnetic hyperfine sub-levels are
coupled by an external magnetic radio frequency (rf) field. We perform a
thorough theoretical analysis of this driven system and present a number of
frequency potentials. The predictions of this analytical investigation are
compared to numerically exact results obtained by a wave packet propagation. We
outline the versatility and flexibility of this new class of potentials and
demonstrate their potential use to build atom optical elements such as
double-wells, interferometers and ringtraps. Moreover, we perform simulations
of interference experiments carried out in rf induced double-well potentials.
We discuss how the nature of the atom-field coupling mechanism gives rise to a
decrease of the interference contrast.
\\ ( http://arXiv.org/abs/physics/0606165 , 822kb)
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Paper: cond-mat/0603011
replaced with revised version Tue, 20 Jun 2006 01:59:40 GMT (96kb)

Title: BCS-BEC crossover in an asymmetric two-component Fermi gas
Authors: Xia-Ji Liu and Hui Hu
Comments: 7 pages + 3 figures; To appear in Europhysics Letters
Subj-class: Statistical Mechanics; Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0603011 , 96kb)
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Paper: quant-ph/0606162
Date: Tue, 20 Jun 2006 06:31:43 GMT (215kb)

Title: Quantum computing with magnetic atoms in optical lattices of reduced
periodicity
Authors: Boris Ravaine, Andrei Derevianko, P.R. Berman
\\
We investigate the feasibility of combining Raman optical lattices with a
quantum computing architecture based on lattice-confined magnetically
interacting neutral atoms. A particular advantage of the standing Raman field
lattices comes from reduced interatomic separations leading to increased
interatomic interactions and improved multi-qubit gate performance.
Specifically, we analyze a $J=3/2$ Zeeman system placed in $% \sigma _{+}-\sigma_{-}$ Raman fields which exhibit $\lambda /4$ periodicity. We find
that the resulting CNOT gate operations times are in the order of millisecond.
We also investigate motional and magnetic-field induced decoherences specific
to the proposed architecture.
\\ ( http://arXiv.org/abs/quant-ph/0606162 , 215kb)
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Paper: quant-ph/0602025
replaced with revised version Tue, 20 Jun 2006 16:54:09 GMT (225kb)

Title: Macroscopic superpositions of superfluid flows
Authors: David W. Hallwood, Jacob Dunningham, Keith Burnett
Comments: 4 pages, 4 figures, submitted to New J. Phys. changed content focus
\\ ( http://arXiv.org/abs/quant-ph/0602025 , 225kb)
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Paper: cond-mat/0606540
Date: Wed, 21 Jun 2006 04:22:44 GMT (524kb)

Title: Axicon Lens for Coherent Matter Waves
Authors: S. R. Muniz, S. D. Jenkins, T. A. B. Kennedy, D. S. Naik, and C. Raman
Comments: 11 pages, 5 figures, Multimedia files (movies) available in our
website: http://www.physics.gatech.edu/chandra/index.htm
Subj-class: Other
\\
We have realized a conical matter wave lens. The repulsive potential of a
focused laser beam was used to launch a Bose-Einstein condensate into a
radially expanding wavepacket whose perfect ring shape was ensured by energy
conservation. In spite of significant interactions between atoms, the spatial
and velocity widths of the ring along its radial dimension remained extremely
narrow, as also confirmed by numerical simulations. Our results open the
possibility for cylindrical atom optics without the perturbing effect of
mean-field interactions.
\\ ( http://arXiv.org/abs/cond-mat/0606540 , 524kb)
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Paper: cond-mat/0606554
Date: Wed, 21 Jun 2006 14:13:32 GMT (168kb)

Title: Input-output theory of cavities in the ultra-strong coupling regime: the
case of a time-independent vacuum Rabi frequency
Authors: Cristiano Ciuti (LPA), Iacopo Carusotto (BEC-CNR-INFM)
Proxy: ccsd ccsd-00080977
Subj-class: Other
\\
We present a full quantum theory for the dissipative dynamics of an optical
cavity in the ultra-strong light-matter coupling regime, in which the vacuum
Rabi frequency is comparable to the electronic transition frequency and the
anti-resonant terms of the light-matter coupling play an important role. In
particular, our model can be applied to the case of intersubband transitions in
doped semiconductor quantum wells embedded in a microcavity. The coupling of
the intracavity photonic mode and of the electronic polarization to the
external, frequency-dependent, dissipation baths is taken into account by means
of quantum Langevin equations in the input-output formalism. Observable spectra
(reflection, absorption, transmission and electroluminescence) are calculated
analytically in the case of a time-independent vacuum Rabi frequency.
\\ ( http://arXiv.org/abs/cond-mat/0606554 , 168kb)
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Paper: cond-mat/0604137
replaced with revised version Wed, 21 Jun 2006 09:35:43 GMT (28kb)

Title: Fermion Cooper Pairing with Unequal Masses: Standard Field Theory
Approach
Authors: Lianyi He, Meng Jin and Pengfei Zhuang
Comments: 13 pages, 2 figures, title changed
Subj-class: Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0604137 , 28kb)
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Paper: cond-mat/0604183
replaced with revised version Wed, 21 Jun 2006 11:27:57 GMT (26kb)

Title: Collisional relaxation of Feshbach molecules and three-body
recombination in 87Rb Bose-Einstein condensates
Authors: G. Smirne, R. M. Godun, D. Cassettari, V. Boyer, C. J. Foot, T. Volz,
N. Syassen, S. D\"urr, G. Rempe, M. D. Lee, K. Goral, T. Koehler
Comments: 4 pages, 3 eps figures
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0604183 , 26kb)
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Paper: cond-mat/0605736
replaced with revised version Tue, 20 Jun 2006 22:51:11 GMT (154kb)

Title: Long Distance Transport of Ultracold Atoms using a 1D optical lattice
Authors: Stefan Schmid, Gregor Thalhammer, Klaus Winkler, Florian Lang, and
Johannes Hecker Denschlag
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0605736 , 154kb)
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Paper: cond-mat/0606569
Date: Thu, 22 Jun 2006 08:40:38 GMT (236kb)

Title: Critical Temperature of a Chromium Condensate
Authors: Konstantin Glaum, Axel Pelster, Hagen Kleinert, and Tilman Pfau
Subj-class: Statistical Mechanics
\\
We calculate the effect of the magnetic dipole-dipole interaction upon the
Bose-Einstein condensation temperature of chromium in the ongoing Stuttgart
experiment. The dipolar shift of the critical temperature depends on the angle
between the symmetry axes of the trap and the aligned atomic magnetic moments,
and is extremal for parallel or orthogonal orientations, respectively. The
difference of both critical temperatures exhibits most clearly the magnetic
dipole-dipole interaction and can be enhanced by increasing both the number of
chromium atoms and the anisotropy of the trap.
\\ ( http://arXiv.org/abs/cond-mat/0606569 , 236kb)
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Paper: cond-mat/0606571
Date: Thu, 22 Jun 2006 11:05:56 GMT (37kb)

Title: Macro-orbitals and microscopic theory of a system of interacting bosons
Authors: Yatendra S. Jain
Comments: 36 pages with 1 figure, related to superfluidity, BEC states, etc
Subj-class: Soft Condensed Matter
\\
Macro-orbital representation of a particle (detailed account given in
cond-mat/0603784) has been used to develop the microscopic theory of a system
of interacting bosons. It concludes that: (i) below certain temperature (say,
$T_{\lambda}$), particles assume a state of (q, -q) bound pairs, (ii) the
$\lambda-$transition is a consequence of inter-particle quantum correlations
clubbed with zero-point repulsion and inter-particle attraction and represents
an onset of the order-disorder of particles in their $\phi-$space followed
simultaneously by their BEC as (q, -q) bound pairs in a state of q = $q_o = \pi/d$ and K = 0, (iii) particles at $T \le T_{\lambda}$ acquire collective
binding which locks them at <k> = 0, <r> = $\lambda/2$ and $\Delta\phi = 2n\pi$
(with n = 1, 2, 3, ...), (iv) the entire system assumes mechanical strain in
inter-particle bonds and behaves like a single macroscopic molecule, (v) there
exists an energy gap between the superfluid and normal fluid phases of the
system, (vi) the $\lambda-$transition represents the twin phenomena of broken
gauge symmetry and phase coherence, (vii) the system does not have p = 0
condensate, (viii) a new kind of quantum quasi-particle "omon" (a phononlike
wave of the oscillations of the momentum coordinates of particles) exists in
superfluid phase, etc. It explains the properties of He-II, including the
origin of quantized vortices, critical velocities, logarithmic singularity of
specific heat, etc. at quantitative level and provides microscopic foundation
to two fluid theory, $\Psi-$theory, idea of macroscopic wave function, etc. The
framework of the theory can unify the physics of interacting bosons and
fermions.
\\ ( http://arXiv.org/abs/cond-mat/0606571 , 37kb)
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Paper: quant-ph/0606180
Date: Wed, 21 Jun 2006 20:53:14 GMT (19kb)

Title: Cantilever cooling with radio frequency circuits
Authors: D. J. Wineland, J. Britton, R. J. Epstein, D. Leibfried, R. B.
Blakestad, K. Brown, J. D. Jost, C. Langer, R. Ozeri, S. Seidelin, and J.
Wesenberg
\\
We consider a method to reduce the kinetic energy in a low-order mode of a
miniature cantilever. If the cantilever contributes to the capacitance of a
driven RF circuit, a force on the cantilever exists due to the electric field
energy stored in the capacitance. If this force acts with an appropriate phase
shift relative to the motion of the cantilever, it can oppose the velocity of
the cantilever, leading to cooling. Such cooling may enable reaching the
quantum regime of cantilever motion.
\\ ( http://arXiv.org/abs/quant-ph/0606180 , 19kb)
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Paper: physics/0606186
Date: Wed, 21 Jun 2006 16:35:20 GMT (6kb)
Date (revised v2): Thu, 22 Jun 2006 18:58:06 GMT (6kb)

Title: Alice and Bob Get Away With It: a playlet
Authors: Anthony Sudbery
Subj-class: Popular Physics
\\
Alice and Bob use Aravind's version of a Bell-Kochen-Specker paradox to fend
off awkward questions about what exactly they were doing in Amsterdam last
week.
\\ ( http://arXiv.org/abs/physics/0606186 , 6kb)
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Paper: cond-mat/0606592
Date: Fri, 23 Jun 2006 03:33:01 GMT (468kb)

Title: Formation of spatial shell structures in the superfluid to Mott
insulator transition
Authors: Simon Foelling, Artur Widera, Torben Mueller, Fabrice Gerbier and
Immanuel Bloch
Subj-class: Other
\\
We report on the direct observation of the transition from a compressible
superfluid to an incompressible Mott insulator by recording the in-trap density
distribution of a Bosonic quantum gas in an optical lattice. Using spatially
selective microwave transitions and spin changing collisions, we are able to
locally modify the spin state of the trapped quantum gas and record the spatial
distribution of lattice sites with different filling factors. As the system
evolves from a superfluid to a Mott insulator, we observe the formation of a
distinct shell structure, in good agreement with theory.
\\ ( http://arXiv.org/abs/cond-mat/0606592 , 468kb)
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Paper: cond-mat/0606609
Date: Fri, 23 Jun 2006 13:58:16 GMT (139kb)

Title: Quantum dynamics of Bose-Hubbard Hamiltonians beyond
Hartree-Fock-Bogoliubov: The Bogoliubov backreaction approximation
Authors: I. Tikhonenkov, J. R. Anglin, and A. Vardi
Subj-class: Other
\\
e formulate a method for studying the quantum field dynamics of ultracold
Bose gases confined within optical lattice potentials, within the lowest
Bloch-band Bose-Hubbard model. Our formalism extends the two-sites results of
Phys. Rev. Lett. {\bf86}, 000568 (2001) to the general case of $M$ lattice
sites. The methodology is based on mapping the Bose-Hubbard Hamiltonian to an
$SU(M)$ pseudospin problem and truncating the resulting hierarchy of dynamical
equations for correlation functions, up to pair-correlations between $SU(M)$
generators. Agreement with few-site exact many-particle calculations is
consistently better than the corresponding Hartree-Fock-Bogoliubov
approximation. Moreover, our approximation compares favorably with a more
elaborate two-particle irreducible effective action formalism, at a fraction of
the analytic and numerical effort.
\\ ( http://arXiv.org/abs/cond-mat/0606609 , 139kb)
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Paper: cond-mat/0606617
Date: Fri, 23 Jun 2006 17:31:07 GMT (105kb)

Title: Spatial Correlation Functions of one-dimensional Bose gases at
Equilibrium
Authors: N.P. Proukakis
Subj-class: Other; Statistical Mechanics
\\
The dependence of the three lowest order spatial correlation functions of a
harmonically confined Bose gas on temperature and interaction strength is
presented at equilibrium. Our analysis is based on a stochastic Langevin
equation for the order parameter of a weakly-interacting gas. Comparison of the
predicted first order correlation functions to those of appropriate mean field
theories demonstrates the potentially crucial role of density fluctuations on
the equilibrium coherence length. Furthermore,the change in both coherence
length and shape of the correlation function, from gaussian to exponential,
with increasing temperature is quantified. Moreover, the presented results for
higher order correlation functions are shown to be in agreeement with existing
predictions. Appropriate consideration of density-density correlations is shown
to facilitate a precise determination of quasi-condensate density profiles,
providing an alternative approach to the bimodal density fits typically used
experimentally.
\\ ( http://arXiv.org/abs/cond-mat/0606617 , 105kb)
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Paper: cond-mat/0602037
replaced with revised version Fri, 23 Jun 2006 17:10:08 GMT (158kb)

Title: Validity of the Lowest Landau Level Approximation for Rotating Bose
Gases
Authors: Alexis G. Morris and David L. Feder
Comments: Ver. 2: Minor modifications to results and text, extended discussion.
8 pages, 9 figures
Subj-class: Mesoscopic Systems and Quantum Hall Effect
\\ ( http://arXiv.org/abs/cond-mat/0602037 , 158kb)
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Paper: cond-mat/0603334
replaced with revised version Fri, 23 Jun 2006 08:18:36 GMT (30kb)

Title: Phases of Bosons or Fermions in confined optical lattices
Authors: H. Heiselberg
Comments: 6 pages, 3 figures, revised and extended
Subj-class: Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0603334 , 30kb)
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Paper: quant-ph/0606200
Date: Fri, 23 Jun 2006 16:26:49 GMT (101kb)

Title: Effective resonant transitions in quantum optical systems: kinematic and
dynamic resonances
Authors: A. B. Klimov, I. Sainz
\\
We show that quantum optical systems preserving the total number of
excitations admit a simple classification of possible resonant transitions
(including effective), which can be classified by analizying the free
Hamiltonian and the corresponding integrals of motion. Quantum systems not
preserving the total number of excitations do not admit such a simple
classification, so that an explicit form of the effective Hamiltonian is needed
to specify the allowed resonances. The structure of the resonant transitions
essentially depends on the algebraic propereties of interacting subsystems.
\\ ( http://arXiv.org/abs/quant-ph/0606200 , 101kb)
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Paper: physics/0603108
replaced with revised version Fri, 23 Jun 2006 02:02:56 GMT (247kb)

Title: Optimizing the Stark-decelerator beamline for the trapping of cold
molecules using evolutionary strategies
Authors: Joop J. Gilijamse, Jochen K\"upper, Steven Hoekstra, Sebastiaan Y. T.
van de Meerakker, Gerard Meijer
Comments: 7 pages, 4 figures (RevTeX); minor corrections (v2)
Subj-class: Instrumentation and Detectors; Accelerator Physics; Atomic Physics
Journal-ref: Phys. Rev. A 73, 063410 (2006)
DOI: 10.1103/PhysRevA.73.063410
\\ ( http://arXiv.org/abs/physics/0603108 , 247kb)
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Paper: cond-mat/0606624
Date: Fri, 23 Jun 2006 22:44:22 GMT (27kb)

Title: Asymmetric two-component Fermi gas with unequal masses
Authors: M. Iskin and C. A. R. Sa de Melo
Comments: 4 pages and 4 figures
Subj-class: Superconductivity; Other
\\
We analyze the zero temperature phase diagram for an asymmetric two-component
Fermi gas as a function of mass anisotropy and population imbalance. We
identify regions corresponding to normal, and uniform or non-uniform superfluid
phases, and find a topological quantum phase transition in the
Bardeen-Cooper-Schrieffer (BCS), unitarity and Bose-Einstein condensation (BEC)
limits. Lastly, we derive the zero temperature low frequency and long
wavelength collective excitation spectrum, and recover the Bogoliubov relation
for weakly interacting dilute bosons in the BEC limit.
\\ ( http://arXiv.org/abs/cond-mat/0606624 , 27kb)
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Paper: cond-mat/0606625
Date: Fri, 23 Jun 2006 22:56:05 GMT (470kb)

Title: Atomtronics: ultracold atom analogs of electronic devices
Authors: B. T. Seaman, M. Kraemer, D. Z. Anderson and M. J. Holland
Subj-class: Statistical Mechanics
\\
Atomtronics focuses on atom analogs of electronic materials, devices and
circuits. A strongly interacting ultracold Bose gas in a lattice potential is
analogous to electrons in solid-state crystalline media. As a consequence of
the band structure, cold atoms in a lattice can exhibit insulator or conductor
properties. P-type and N-type material analogs can be created by introducing
impurity sites into the lattice. Current through an atomtronic wire is
generated by connecting the wire to an atomtronic battery which maintains the
two contacts at different chemical potentials. The design of an atomtronic
diode with a strongly asymmetric current-voltage curve exploits the existence
of superfluid and insulating regimes in the phase diagram. The atomtronic
analog of a bipolar junction transistor exhibits large negative gain. Our
results provide the building blocks for more advanced atomtronic devices and
circuits such as amplifiers, oscillators and fundamental logic gates.
\\ ( http://arXiv.org/abs/cond-mat/0606625 , 470kb)
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Paper: cond-mat/0606638
Date: Sun, 25 Jun 2006 19:17:07 GMT (138kb)

Title: A Degenerate Bose-Fermi Mixture of Metastable Atoms
Authors: J. M. McNamara, T. Jeltes, A. S. Tychkov, W. Hogervorst and W. Vassen
Comments: 4 pages, 3 figures submitted to PRL
Subj-class: Statistical Mechanics
\\
We report the observation of simultaneous quantum degeneracy in a dilute
gaseous Bose-Fermi mixture of metastable atoms. Sympathetic cooling of helium-3
(fermion) by helium-4 (boson), both in the lowest triplet state, allows us to
produce ensembles containing more than 10^6 atoms of each isotope at
temperatures below 1 micro-Kelvin, and achieve a fermionic degeneracy parameter
of T/Tf=0.45. Due to their high internal energy, the detection of individual
metastable atoms with sub-nanosecond time resolution is possible, permitting
the study of bosonic and fermionic quantum gases with unprecedented precision.
This may lead to metastable helium becoming the mainstay of quantum atom
optics.
\\ ( http://arXiv.org/abs/cond-mat/0606638 , 138kb)
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\\
Paper: cond-mat/0606642
Date: Sun, 25 Jun 2006 20:30:23 GMT (698kb)

Title: Imaging the Mott Insulator Shells using Atomic Clock Shifts
Authors: Gretchen K. Campbell, Jongchul Mun, Micah Boyd, Patrick Medley, Aaron
E. Leanhardt, Luis Marcassa, David E. Pritchard, and Wolfgang Ketterle
Subj-class: Other
\\
Microwave spectroscopy was used to probe the superfluid-Mott Insulator
transition of a Bose-Einstein condensate in a 3D optical lattice. Using density
dependent transition frequency shifts we were able to spectroscopically
distinguish sites with different occupation numbers, and to directly image
sites with occupation number n=1 to n=5 revealing the shell structure of the
Mott Insulator phase. We use this spectroscopy to determine the onsite
interaction and lifetime for individual shells.
\\ ( http://arXiv.org/abs/cond-mat/0606642 , 698kb)
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\\
Paper: cond-mat/0606654
Date: Mon, 26 Jun 2006 09:50:28 GMT (13kb)

Title: Nonequilibrium Bose systems and nonground-state Bose-Einstein
condensates
Authors: V.I. Yukalov
Comments: Latex file, 16 pages, no figures
Subj-class: Statistical Mechanics; Mesoscopic Systems and Quantum Hall Effect
Journal-ref: Laser Phys. Lett. 3 (2006) 406-414
\\
The theory of resonant generation of nonground-state Bose-Einstein
condensates is extended to Bose-condensed systems at finite temperature. The
generalization is based on the notion of representative statistical ensembles
for Bose systems with broken global gauge symmetry. Self-consistent equations
are derived describing an arbitrary nonequilibrium nonuniform Bose system. The
notion of finite-temperature topological coherent modes, coexisting with a
cloud of noncondensed atoms, is introduced. It is shown that resonant
generation of these modes is feasible for a gas of trapped Bose atoms at finite
temperature.
\\ ( http://arXiv.org/abs/cond-mat/0606654 , 13kb)
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Paper: cond-mat/0604164
replaced with revised version Mon, 26 Jun 2006 07:58:08 GMT (385kb)

Title: Fragmented condensates due to frustration of cold atoms in optical
lattices
Authors: J. J. Garcia-Ripoll, J. Pachos
Subj-class: Strongly Correlated Electrons
\\ ( http://arXiv.org/abs/cond-mat/0604164 , 385kb)
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\\
Paper: quant-ph/0606210
Date: Mon, 26 Jun 2006 07:31:14 GMT (531kb)

Title: Quantum study of information delay in electromagetically induced
transparency
Authors: Magnus T.L. Hsu, Gabriel Hetet, Oliver Glockl, Jevon J. Longdell, Ben
C. Buchler, Hans-A. Bachor, and Ping Koy Lam
\\
Using electromagnetically induced transparency (EIT), it is possible to delay
and store light in atomic ensembles. Theoretical modelling and recent
experiments have suggested that the EIT storage mechanism can be used as a
memory for quantum information. We present experiments that quantify the noise
performance of an EIT system for conjugate amplitude and phase quadratures. It
is shown that our EIT system adds excess noise to the delayed light that has
not hitherto been predicted by published theoretical modelling. In analogy with
other continuous-variable quantum information systems, the performance of our
EIT system is characterised in terms of conditional variance and signal
transfer.
\\ ( http://arXiv.org/abs/quant-ph/0606210 , 531kb)
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\\
Paper: physics/0606214
Date: Mon, 26 Jun 2006 10:09:25 GMT (90kb)

Title: Optical Lattice Polarization Effects on Hyperpolarizability of Atomic
Clock Transitions
Authors: A. V. Taichenachev and V. I. Yudin, V. D. Ovsiannikov, V. G.
Pal'chikov
Comments: 4 pages, RevTeX4, 2 eps figs
Subj-class: Atomic Physics; Optics
\\
The light-induced frequency shift due to the hyperpolarizability (i.e. terms
of second-order in intensity) is studied for a forbidden optical transition,
$J$=0$\to$$J$=0. A simple universal dependence on the field ellipticity is
obtained. This result allows minimization of the second-order light shift with
respect to the field polarization for optical lattices operating at a magic
wavelength (at which the first-order shift vanishes). We show the possibility
for the existence of a magic elliptical polarization, for which the
second-order frequency shift vanishes. The optimal polarization of the lattice
field can be either linear, circular or magic elliptical. The obtained results
could improve the accuracy of lattice-based atomic clocks.
\\ ( http://arXiv.org/abs/physics/0606214 , 90kb)
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\\
Paper: physics/0606223
Date: Mon, 26 Jun 2006 14:21:28 GMT (396kb)

Title: Tailoring of motional states in double-well potentials by time-dependent
processes
Authors: Kari Harkonen, Ollijuhani Karki, Kalle-Antti Suominen
Comments: 9 pages, 11 figures, 25 references; submitted to PRA
Subj-class: Atomic Physics
\\
We show that the vibrational state tailoring method developed for molecular
systems can be applied for cold atoms in optical lattices. The original method
is based on a three-level model interacting with two strong laser pulses in a
counterintuitive sequence [M. Rodriguez et al., Phys. Rev. A 62, 053413
(2000)]. Here we outline the conditions for achieving similar dynamics with
single time-dependent potential surfaces. It is shown that guided switching
between diabatic and adiabatic evolution has an essential role in this system.
We also show that efficient and precise tailoring of motional states in optical
lattices can be achieved, for instance, simply by superimposing two lattices
and moving them with respect to each other.
\\ ( http://arXiv.org/abs/physics/0606223 , 396kb)
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Till next week,
Matt.

--
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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/
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Received on Tue Jun 27 2006 - 15:09:29 EST

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