Dear subscribers,
This week's selection was compiled by Chao Feng, and contains 38 new abstracts
and 12 replacements.
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arXiv:1003.3048 (*cross-listing*)
Date: Mon, 15 Mar 2010 23:21:56 GMT (173kb)
Date (revised v2): Tue, 18 May 2010 20:08:15 GMT (339kb,D)
Title: Tunable disorder in a crystal of cold polar molecules
Authors: Felipe Herrera and Marina Litinskaya and Roman V. Krems
Categories: physics.atom-ph cond-mat.other physics.chem-ph quant-ph
\\
In the present work, we demonstrate the possibility of controlling by an
external field the dynamics of collective excitations (excitons) of molecules
on an optical lattice. We show that a suitably chosen two-species mixture of
ultracold polar molecules loaded on an optical lattice forms a phononless
crystal, where exciton-impurity interactions can be controlled by applying an
external electric field. This can be used for the controlled creation of
many-body entangled states of ultracold molecules and the time-domain quantum
simulation of disorder-induced localization and delocalization of quantum
particles.
\\ ( http://arxiv.org/abs/1003.3048 , 339kb)
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arXiv:1005.2420
Date: Thu, 13 May 2010 20:33:46 GMT (398kb)
Title: Comment on "Inequivalence between the Schrodinger equation and the
Madelung hydrodynamic equations"
Authors: Vel Hushwater
Categories: quant-ph
\\
In the paper with the above-noted title, T. C. Wallstrom claims that the
description of the particle's motion as a certain "conservative" diffusion is
not equivalent to quantum mechanics in spite of the fact that the Madelung
"hydrodynamic" equations, which provide the description of such a diffusion,
can be converted to the Schrodinger equation. He pointed out that such a
stochastic theory can be regarded as equivalent to conventional quantum
mechanics only if they can derive from it not just the Madelung equations but
also the condition that the circulation of the "probability fluid" is always
quantized, which is equivalent the condition for the single-valuedness of the
wave function. We, however, show that the single-valuedness of the wave
function required in quantum mechanics, is not an auxiliary condition but a
property of all solutions of the Schrodinger equation. Based on the one-to-one
correspondence between solutions of the Schrodinger and the Madelung equations
this means that the quantization of the circulation of the "probability fluid"
is a property of all solutions of the Madelung equations.
\\ ( http://arxiv.org/abs/1005.2420 , 398kb)
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arXiv:1005.2483
Date: Fri, 14 May 2010 09:25:20 GMT (400kb)
Title: Disordered one-dimensional Bose-Fermi mixtures: The Bose-Fermi glass
Authors: Fran\c{c}ois Cr\'epin, Gergely Zar\'and, Pascal Simon
Categories: cond-mat.quant-gas cond-mat.str-el
Comments: 4 pages, 2 figures
\\
We analyze an interacting Bose-Fermi mixture in a 1D disordered potential
using a combination of renormalization group and variational methods. We obtain
the complete phase diagram in the incommensurate case as a function of bosonic
and inter-species interaction strengths, in the weak disorder limit. We find
that the system is characterized by several phase transitions between
superfluid and various glassy insulating states, including a new Bose-Fermi
glass phase, where both species are coupled and localized. We show that the
dynamical structure factor, as measured through Bragg scattering experiments,
can distinguish between the various localized phases and probe their dynamics.
\\ ( http://arxiv.org/abs/1005.2483 , 400kb)
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arXiv:1005.2493
Date: Fri, 14 May 2010 10:23:18 GMT (173kb)
Title: Collective excitations of a dipolar Bose-Einstein condensate
Authors: G. Bismut, B. Pasquiou, E. Mar\'echal, P. Pedri, L. Vernac, O. Gorceix
and B. Laburthe-Tolra
Categories: cond-mat.quant-gas quant-ph
Comments: 4 pages, 4 figures
\\
We have measured the effect of dipole-dipole interactions on the frequency of
a collective mode of a Bose-Einstein condensate. At relatively large numbers of
atoms, the experimental measurements are in good agreement with zero
temperature theoretical predictions based on the Thomas Fermi approach.
Experimental results obtained for the dipolar shift of a collective mode show a
larger dependency to both the trap geometry and the atom number than the ones
obtained when measuring the modification of the condensate aspect ratio due to
dipolar forces. These findings are in good agreement with simulations based on
a gaussian ansatz.
\\ ( http://arxiv.org/abs/1005.2493 , 173kb)
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arXiv:1005.2520
Date: Fri, 14 May 2010 13:26:56 GMT (41kb,D)
Title: Asymptotically exact trial wave functions for yrast states of rotating
Bose gases
Authors: Susanne Viefers and Mathieu Taillefumier
Categories: cond-mat.quant-gas
\\
We revisit the composite fermion (CF) construction of the lowest angular
momentum yrast states of rotating Bose gases with weak short range interaction.
For angular momenta at and below the single vortex, $L \leq N$, the overlaps
between these trial wave functions and the corresponding exact solutions {\it
increase} with increasing system size and appear to approach unity in the
thermodynamic limit. In the special case $L=N$, this remarkable behaviour was
previously observed numerically. Here we present methods to address this point
analytically, and find strongly suggestive evidence in favour of similar
behaviour for all $L \leq N$. While not constituting a fully conclusive proof
of the converging overlaps, our results do demonstrate a striking similarity
between the analytic structure of the exact ground state wave functions at $L
\leq N$, and that of their CF counterparts. Results are given for two different
projection methods commonly used in the CF approach.
\\ ( http://arxiv.org/abs/1005.2520 , 41kb)
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arXiv:1005.2559
Date: Fri, 14 May 2010 15:55:51 GMT (437kb,D)
Title: Multipartite entangled states with two bosonic modes and qubits
Authors: P. P. Munhoz, F. L. Semi\~ao
Categories: quant-ph
Comments: 10 pages, 5 figures, REVTeX 4.1, BibTeX
\\
We theoretically investigate the role of different phases of coupling
constants in the dynamics of atoms and two cavity modes, observing
deterministic generation of prototype or hybrid Bell, W, GHZ, and cluster
states. Commonly induced dipole-dipole interactions (far-off resonance) are
inhibited between particular pairs of qubits under suitable choice of that
phases. We evaluate the generation fidelities when imperfections such as
dissipative environments and time precision errors are considered. We show
violation of local realism for the generated cluster state under such
imperfections, even when approaching the weak coupling regime.
\\ ( http://arxiv.org/abs/1005.2559 , 437kb)
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arXiv:1005.2576
Date: Fri, 14 May 2010 17:19:53 GMT (144kb)
Title: Double resonances in Borromean heteronuclear triatomic systems
Authors: F. Bringas, M. T. Yamashita, T. Frederico and L. Tomio
Categories: cond-mat.quant-gas physics.atom-ph
\\
We investigate the occurrence of Borromean three-body continuum s-wave
resonances, in an $\alpha\alpha\beta$ system for large negative two-body
scattering lengths. The energy and width are determined by a scaling function
with arguments given by energy ratios of the two-body virtual state subsystem
energies with the shallowest three-body bound state. The Borromean continuum
resonances emerging from Efimov states present a peculiar behavior for trapped
ultracold atoms near a Feshbach resonance: two resonances with equal energies
at different values of the scattering length. The corresponding three-body
recombination peaks should merge as the temperature is raised, with one moving
towards lower values of the scattering length as the other moves to larger
values.
\\ ( http://arxiv.org/abs/1005.2576 , 144kb)
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arXiv:1005.2581 (*cross-listing*)
Date: Fri, 14 May 2010 17:41:53 GMT (59kb)
Title: A Performance Comparison of CUDA and OpenCL
Authors: Kamran Karimi, Neil G. Dickson, and Firas Hamze
Categories: cs.PF cs.DC physics.comp-ph
Comments: 10 pages, 6 Tables, 5 Figures
\\
CUDA and OpenCL offer two different interfaces for programming GPUs. OpenCL
is an open standard that can be used to program CPUs, GPUs, and other devices
from different vendors, while CUDA is specific to NVIDIA GPUs. Although OpenCL
promises a portable language for GPU programming, its generality may entail a
performance penalty. In this paper, we compare the performance of CUDA and
OpenCL using complex, near-identical kernels. We show that when using NVIDIA
compiler tools, converting a CUDA kernel to an OpenCL kernel involves minimal
modifications. Making such a kernel compile with ATI's build tools involves
more modifications. Our performance tests measure and compare data transfer
times to and from the GPU, kernel execution times, and end-to-end application
execution times for both CUDA and OpenCL.
\\ ( http://arxiv.org/abs/1005.2581 , 59kb)
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arXiv:1005.2610
Date: Fri, 14 May 2010 19:16:19 GMT (2549kb)
Title: Generation of inter-component dispersive shocks and dark-bright soliton
trains in counterflowing superfluids
Authors: C. Hamner, J.J. Chang, P. Engels, M. A. Hoefer
Categories: cond-mat.quant-gas
Comments: 5 pages, 4 figures
\\
Superfluids can exhibit an intriguing variety of nonlinear effects. Using two
distinguishable components of a Bose-Einstein condensate, we investigate the
counterflow of two superfluids in a narrow channel. We present the first
experimental observation of inter-component dispersive shock waves and
demonstrate that they consist of trains of dark-bright solitons. Our
observations are theoretically interpreted with three-dimensional numerical
simulations of coupled Gross-Pitaevskii equations. Nonlinear self-steepening as
well as a counterflow-induced modulational instability are identified as two
central processes in the dynamics. We also present the first experimental
evidence for a novel dark-dark soliton in a binary BEC that we observe during
the mixing of two superfluid components.
\\ ( http://arxiv.org/abs/1005.2610 , 2549kb)
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arXiv:1005.2635
Date: Fri, 14 May 2010 21:55:37 GMT (88kb)
Title: Coherence freeze in an optical lattice investigated via pump-probe
spectroscopy
Authors: Samansa Maneshi, Chao Zhuang, Christopher R. Paul, Luciano S. Cruz,
and Aephraim M. Steinberg
Categories: quant-ph
Comments: 4 pages, 5 figures
\\
Motivated by our observation of fast echo decay and a surprising coherence
freeze, we have developed a pump-probe spectroscopy technique for vibrational
states of ultracold $^{85}$Rb atoms in an optical lattice to gain information
about the memory dynamics of the system. We use pump-probe spectroscopy to
monitor the time-dependent changes of frequencies experienced by atoms and to
characterize the probability distribution of these frequency trajectories. We
show that the inferred distribution, unlike a naive microscopic model of the
lattice, correctly predicts the main features of the observed echo decay.
\\ ( http://arxiv.org/abs/1005.2635 , 88kb)
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arXiv:1005.2645
Date: Sat, 15 May 2010 01:48:28 GMT (87kb)
Title: Time-resolved density correlations as probe of squeezing in toroidal
Bose-Einstein condensates
Authors: Michael Uhlmann
Categories: cond-mat.quant-gas
Comments: 18 pages, IOP style
\\
I study the evolution of mean field and linear quantum fluctuations in a
toroidal Bose-Einstein condensate, whose interaction strength is quenched from
a finite (repulsive) value to zero. The azimuthal equal-time density-density
correlation function is calculated and shows temporal oscillations with twice
the (final) excitation frequencies after the transition. These oscillations are
a direct consequence of positive and negative frequency mixing during
non-adiabatic evolution. I will argue that a time-resolved measurement of the
equal-time density correlator might be used to calculate the moduli of the
Bogoliubov coefficients and thus the amount of squeezing imposed on a mode,
i.e., the number of atoms excited out of the condensate.
\\ ( http://arxiv.org/abs/1005.2645 , 87kb)
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arXiv:1005.2649
Date: Sat, 15 May 2010 04:49:14 GMT (303kb)
Title: System size scaling of topological defect creation in a second-order
dynamical quantum phase transition
Authors: Michael Uhlmann, Ralf Sch\"utzhold, Uwe R. Fischer
Categories: cond-mat.stat-mech gr-qc quant-ph
Comments: 19 pages of IOP style, 6 figures
\\
We investigate the system size scaling of the net defect number created by a
rapid quench in a second-order quantum phase transition from an O(N) symmetric
state to a phase of broken symmetry. Using a controlled mean-field expansion
for large $N$, we find that the net defect number variance in general convex
volumina scales like the surface area of the sample. For short-range
correlations, this behaviour follows generally from spatial and internal
symmetries. Conversely, if spatial isotropy is broken, e.g., by a lattice, and
in addition long-range periodic correlations develop in the broken-symmetry
phase, we get the rather counterintuitive result that the scaling strongly
depends on the dimension being even or odd: For even dimensions, the net defect
number variance scales like the surface area squared, with a prefactor
oscillating with the system size, while for odd dimensions, it essentially
vanishes.
\\ ( http://arxiv.org/abs/1005.2649 , 303kb)
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arXiv:1005.2751
Date: Sun, 16 May 2010 14:13:27 GMT (4kb)
Title: Finite temperature Schr\"odinger Equation
Authors: Xiang-Yao Wu, Xiao-Jing Liu, Bai-Jun Zhang, Yi-Heng Wu, Qing-Cai Wang,
Yan Wang and Jing-Wu Li
Categories: physics.gen-ph quant-ph
\\
We know the Schr\"odinger equation describes the dynamics of quantum systems,
which didn't include temperature. In this paper, we propose a new finite
temperature Schr\"odinger equation, which can describe the quantum systems in
an arbitrary temperature.
\\ ( http://arxiv.org/abs/1005.2751 , 4kb)
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arXiv:1005.2864
Date: Mon, 17 May 2010 10:15:29 GMT (52kb)
Title: Turbulent superfluid as continuous vortex mixture
Authors: V.I. Yukalov
Categories: cond-mat.quant-gas quant-ph
Comments: Latex file, 22 pages, one figure
Journal-ref: Laser Phys. Lett. 7 (2010) 467-476
\\
A statistical model is advanced for describing quantum turbulence in a
superfluid system with Bose-Einstein condensate. Such a turbulent superfluid
can be realized for trapped Bose atoms subject to either an alternating
trapping potential or to an alternating magnetic field modulating the atomic
scattering length by means of Feshbach resonance. The turbulent system is
represented as a continuous mixture of states each of which is characterized by
its own vorticity corresponding to a particular vortex.
\\ ( http://arxiv.org/abs/1005.2864 , 52kb)
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arXiv:1005.2938
Date: Mon, 17 May 2010 14:47:08 GMT (1375kb)
Title: Correlation versus commensurability effects for finite bosonic systems
in one-dimensional lattices
Authors: Ioannis Brouzos and Sascha Z\"ollner and Peter Schmelcher
Categories: cond-mat.quant-gas quant-ph
Comments: 16 pages, 16 figures
Journal-ref: Phys. Rev. A 81, 053613 (2010)
DOI: 10.1103/PhysRevA.81.053613
\\
We investigate few-boson systems in finite one-dimensional multi-well traps
covering the full interaction crossover from uncorrelated to fermionized
particles. Our treatment of the ground state properties is based on the
numerically exact Multi-Configurational Time-Dependent Hartree method. For
commensurate filling we trace the fingerprints of localisation, as the
interaction strength increases, in several observables like reduced density
matrices, fluctuations and momentum distribution. For filling factor larger
than one we observe on-site repulsion effects in the densities and
fragmentation of particles beyond the validity of the Bose-Hubbard model upon
approaching the Tonks-Girardeau limit. The presence of an incommensurate
fraction of particles induces incomplete localisation and spatial modulations
of the density profiles, taking into account the finite size of the system.
\\ ( http://arxiv.org/abs/1005.2938 , 1375kb)
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arXiv:1005.3040
Date: Mon, 17 May 2010 20:32:02 GMT (13kb)
Title: Spin oscillations of the normal polarized Fermi gas at Unitarity
Authors: Alessio Recati and Sandro Stringari
Categories: cond-mat.quant-gas
Comments: 5 pages, 1 figure
\\
Using density functional theory in a time dependent approach we determine the
frequencies of the compressional modes of the normal phase of a Fermi gas at
unitarity as a function of its polarization. Our energy functional accounts for
the typical elastic deformations exhibited by Landau theory of Fermi liquids.
The comparison with the available experiments is biased by important
collisional effects affecting both the {\it in phase} and the {\it out of
phase} oscillations even at the lowest temperatures. New experiments in the
collisionless regime would provide a crucial test of the applicability of
Landau theory to the dynamics of these strongly interacting normal Fermi gases.
\\ ( http://arxiv.org/abs/1005.3040 , 13kb)
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arXiv:1005.3069
Date: Mon, 17 May 2010 22:35:12 GMT (1519kb)
Title: Open quantum systems approach to atomtronics
Authors: R. A. Pepino, J. Cooper, D. Meiser, D. Z. Anderson, and M. J. Holland
Categories: quant-ph physics.atom-ph
Comments: 10 pages, 10 figures, 1 table
\\
We derive a quantum master equation to treat quantum systems interacting with
multiple reservoirs. The formalism is used to investigate atomic transport
across a variety of lattice configurations. We demonstrate how the behavior of
an electronic diode, a field-effect transistor, and a bipolar junction
transistor can be realized with neutral, ultracold atoms trapped in optical
lattices. An analysis of the current fluctuations is provided for the case of
the atomtronic diode. Finally, we show that it is possible to demonstrate AND
logic gate behavior in an optical lattice.
\\ ( http://arxiv.org/abs/1005.3069 , 1519kb)
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arXiv:1005.3081
Date: Tue, 18 May 2010 00:53:26 GMT (1014kb,D)
Title: Fluctuations and correlations in rotating Bose-Einstein condensates
Authors: Soheil Baharian and Gordon Baym
Categories: cond-mat.quant-gas
\\
We investigate the effect of correlations on the properties of the ground
state of the rotating Bose gas when Bogoliubov fluctuations are added to the
mean-field ground state of a single-vortex system. We demonstrate that the
correlations induced by the fluctuations lower the energy compared to that of
the mean-field ground state, that the vortex acquires a finite (constant)
density at its core, and that an unstable mode with negative energy (for
rotations slower than a critical frequency) emerges in the energy spectrum
which points at a better state for slow rotation rates. We find, in the
mean-field picture, the critical rotation frequencies for transitions from the
0- to 1-vortex and from 1- to 2-vortex states and also the rotation frequency
for the appearance of a metastable state supporting an off-center vortex in the
cloud and its {\lq\lq}mirror{\rq\rq} vortex in the evanescent tail of the
cloud.
\\ ( http://arxiv.org/abs/1005.3081 , 1014kb)
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arXiv:1005.3090
Date: Tue, 18 May 2010 02:33:45 GMT (653kb)
Title: Domain wall dynamics in a two-component Bose-Mott insulator
Authors: Stefan S. Natu and Erich J. Mueller
Categories: cond-mat.quant-gas
Comments: 6 pages, 5 figures submitted to PRA
\\
We model the dynamics of two species of bosonic atoms trapped in an optical
lattice within the Mott regime by mapping the system onto a spin model. A field
gradient breaks the cloud into two domains. We study how the domain wall
evolves under adiabatic and diabatic changes of this gradient. We determine the
timescales for adiabaticity, and study how temperature evolves for slow ramps.
We show that after large, sudden changes of the field gradient, the system does
not equilibrate on typical experimental timescales. We find interesting spin
dynamics even when the initial temperature is large compared to the
super-exchange energy. We discuss the implication of our results for
experiments wishing to use such a two-component system for thermometry, or as
part of a cooling scheme.
\\ ( http://arxiv.org/abs/1005.3090 , 653kb)
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arXiv:1005.3117
Date: Tue, 18 May 2010 08:07:34 GMT (7kb)
Title: Effective Mass Schrodinger Equation via Point Canonical Transformation
Authors: Altug Arda and Ramazan Sever
Categories: quant-ph
Comments: 10 pages
\\
Exact solutions of effective radial Schr\"{o}dinger equation are obtained for
some inverse potentials by using the point canonical transformation. The energy
eigenvalues and the corresponding wave functions are calculated by using a set
of mass distributions
\\ ( http://arxiv.org/abs/1005.3117 , 7kb)
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arXiv:1005.3129
Date: Tue, 18 May 2010 09:45:19 GMT (664kb)
Title: Ab-initio phase diagram of ultracold 87-Rb in an one-dimensional
two-color superlattice
Authors: Felix Schmitt, Markus Hild, Robert Roth
Categories: cond-mat.quant-gas
Comments: 11 pages, 8 figures, 3 tables
\\
We investigate the ab-initio phase diagram of ultracold 87-Rb atoms in an
one-dimensional two-color superlattice. Using single-particle band structure
calculations we map the experimental setup onto the parameters of the
Bose-Hubbard model. This ab-initio ansatz allows us to express the phase
diagrams in terms of the experimental control parameters, i.e., the intensities
of the lasers that form the optical superlattice. In order to solve the
many-body problem for experimental system sizes we adopt the density-matrix
renormalization-group algorithm. A detailed study of convergence and
finite-size effects for all observables is presented. Our results show that all
relevant quantum phases, i.e., superfluid, Mott-insulator, and quasi
Bose-glass, can be accessed through intensity variation of the lasers alone.
However, it turns out that the phase diagram is strongly affected by the
longitudinal trapping potential.
\\ ( http://arxiv.org/abs/1005.3129 , 664kb)
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arXiv:1005.3141
Date: Tue, 18 May 2010 10:17:10 GMT (810kb,D)
Title: A BCS wavefunction approach to the BEC-BCS crossover of
exciton-polariton condensates
Authors: Tim Byrnes, Tomoyuki Horikiri, Natsuko Ishida, Yoshihisa Yamamoto
Categories: cond-mat.quant-gas cond-mat.mes-hall
Comments: 10 pages, 3 figures
\\
The crossover between low and high density regimes of exciton-polariton
condensates is examined using a BCS wavefunction approach. Our approach is an
extension of the BEC-BCS crossover theory for excitons, but includes a cavity
photon field. The approach can describe both the low density limit, where the
system can be described as a Bose-Einstein condensate (BEC) of
exciton-polaritons, and the high density limit, where the system enters a
photon dominated regime. In contrast to the exciton BEC-BCS crossover where the
system approaches an electron-hole plasma, the polariton high density limit has
strongly correlated electron-hole pairs. At intermediate densities, there is a
regime with BCS-like properties, with a peak at non-zero momentum of the
singlet pair function. We calculate the expected photoluminescence and give
several experimental signatures of the crossover.
\\ ( http://arxiv.org/abs/1005.3141 , 810kb)
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arXiv:1005.3152
Date: Tue, 18 May 2010 10:42:17 GMT (1281kb)
Title: Fiber-comb-stabilized light source at 556 nm for magneto-optical
trapping of ytterbium
Authors: Masami Yasuda, Takuya Kohno, Hajime Inaba, Yoshiaki Nakajima, Kazumoto
Hosaka, Atsushi Onae, and Feng-Lei Hong
Categories: physics.atom-ph physics.optics
Comments: 18 pages, 6 figures, submitted to and accepted by J. Opt. Soc. Am. B
(ID 125081)
Journal-ref: J. Opt. Soc. Am. B, 2010 (ID 125081)
\\
A frequency-stabilized light source emitting at 556 nm is realized by
frequency-doubling a 1112-nm laser, which is phase-locked to a fiber-based
optical frequency comb. The 1112-nm laser is either an ytterbium (Yb)-doped
distributed feedback fiber laser or a master-slave laser system that uses an
external cavity diode laser as a master laser. We have achieved the continuous
frequency stabilization of the light source over a five-day period. With the
light source, we have completed the second-stage magneto-optical trapping (MOT)
of Yb atoms using the 1S0 - 3P1 intercombination transition. The temperature of
the ultracold atoms in the MOT was 40 uK when measured using the time-of-flight
method, and this is sufficient for loading the atoms into an optical lattice.
The fiber-based frequency comb is shown to be a useful tool for controlling the
laser frequency in cold-atom experiments.
\\ ( http://arxiv.org/abs/1005.3152 , 1281kb)
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arXiv:1005.3167 (*cross-listing*)
Date: Tue, 18 May 2010 12:03:05 GMT (1463kb)
Title: Pipelike current-carrying vortices in two-component condensates
Authors: M.N. Chernodub and A.S. Nedelin
Categories: hep-th cond-mat.supr-con hep-ph
Comments: 11 pages, 14 figures, RevTex 4.1
Report-no: UUITP-20/10
\\
We study straight vortices with global longitudinal currents in the
Bogomol'ny limit of the Abelian Higgs model with two charged scalar fields. The
model possesses global SU(2) and local electromagnetic U(1) symmetries
spontaneously broken to global U(1) group, and corresponds to a semilocal limit
of the standard electroweak model. We show that the contribution of the global
SU(2) current to the vortex energy is proportional to the total current
squared. Locally, these vortices carry also longitudinal electromagnetic
currents, while the total electromagnetic current flowing through a transverse
section of the vortex is always zero. The vortices with high winding numbers
have, in general, a nested pipelike structure. The magnetic field of the vortex
is concentrated at a certain distance from the geometric center of the vortex,
thus resembling a ``pipe''. This magnetic pipe is layered between two
electrically charged pipes that carry longitudinal electric currents in
opposite directions.
\\ ( http://arxiv.org/abs/1005.3167 , 1463kb)
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arXiv:1005.3206
Date: Tue, 18 May 2010 14:23:12 GMT (511kb)
Title: Luttinger liquid in superlattice structures: atomic gases, quantum dots
and the classical Ising chain
Authors: Aranya B Bhattacherjee, Pradip Jha, Tarun Kumar and ManMohan
Categories: cond-mat.mes-hall
Comments: 7 figures
\\
We study physical properties of a Luttinger liquid in a superlattice which is
characterized by alternating two tunneling parameters. Employing the
Bosonization approach, we describe the corresponding Hubbard model by the
equivalent Tomonoga-Luttinger model. We analyze the spin-charge separation and
transport property as the difference between the two tunneling parameter
increases. We suggest that cold Fermi gases trapped in a bichromatic optical
lattice and coupled quantum dots offer the opportunity to measure these effects
in a convenient manner. We also study the classical Ising chain with two
tunneling parameters. We found that the classical two-point correlator
decreases as the difference between the two tunneling parameter increases.
\\ ( http://arxiv.org/abs/1005.3206 , 511kb)
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arXiv:1005.3239
Date: Tue, 18 May 2010 16:09:25 GMT (597kb)
Title: Competition between Normal Superfluidity and Larkin-Ovchinnikov Phases
of Polarized Fermi Gases in Elongated Traps
Authors: J.C. Pei, J. Dukelsky, W. Nazarewicz
Categories: cond-mat.quant-gas nucl-th
Comments: 4 pages, 4 figures
\\
By applying the recently proposed antisymmetric superfluid local density
approximation (ASLDA) to strongly interacting polarized atomic gases in
elongated traps, we predict clear signals of a type of Larkin-Ovchinnikov (LO)
phase that could be accessible by increasing adiabatically the trap aspect
ratio. We compare ASLDA with the Superfluid Local Density Approximation (SLDA),
previously introduced for unpolarized systems. In particular, we find that the
deformation of the superfluid core in distorted traps that appears in the
ground state solution of SLDA as well as in some Bogoliubov-de Gennes
treatments, is washed out in more realistic ASLDA calculations.
\\ ( http://arxiv.org/abs/1005.3239 , 597kb)
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arXiv:1005.3356
Date: Wed, 19 May 2010 03:39:28 GMT (164kb)
Title: Bounds for multipartite concurrence
Authors: Ming Li, Shao-Ming Fei and Zhi-Xi Wang
Categories: quant-ph
Comments: 8 pages
Journal-ref: Rep. Math. Phys. 65(2010)289-296
\\
We study the entanglement of a multipartite quantum state. An inequality
between the bipartite concurrence and the multipartite concurrence is obtained.
More effective lower and upper bounds of the multipartite concurrence are
obtained. By using the lower bound, the entanglement of more multipartite
states are detected.
\\ ( http://arxiv.org/abs/1005.3356 , 164kb)
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arXiv:1005.3372 (*cross-listing*)
Date: Wed, 19 May 2010 07:48:40 GMT (2238kb)
Title: Nanometer-scale spatial modulation of an inter-atomic interaction in a
Bose-Einstein condensate
Authors: Rekishu Yamazaki and Shintaro Taie and Seiji Sugawa and Yoshiro
Takahashi
Categories: physics.atom-ph cond-mat.quant-gas quant-ph
\\
We demonstrate nanometer-scale spatial control of inter-atomic interactions
in a Bose-Einstein condensate of ytterbium(Yb). A pulsed optical standing wave,
tuned near an optical Feshbach resonance varies the s-wave scattering length
continuously across the standing wave pattern. The modulated mean-field energy
with a spatial period of every 278 nm is monitored by a diffraction pattern in
a time-of-flight image. We observe a wide scattering length control of up to
160 nm. The demonstrated spatial modulation of the scattering length proves
that the high resolution control of atomic interactions is possible.
\\ ( http://arxiv.org/abs/1005.3372 , 2238kb)
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\\
arXiv:1005.3408 (*cross-listing*)
Date: Wed, 19 May 2010 10:40:24 GMT (8kb)
Title: Excitation of Quantized Longitudinal Electric Waves in a Degenerate
Fermi Gas
Authors: Levan N. Tsintsadze
Categories: physics.plasm-ph astro-ph.CO quant-ph
Comments: Submitted to Physical Review E
\\
The system of electron beam - degenerate Fermi gas in a magnetic field is
investigated. Instabilities of the quantized longitudinal electric waves are
studied by a newly derived dispersion equation. Novel branches of longitudinal
waves are found, which have no analogies without the Landau quantization.
Growth rates of these new modes are obtained. The excitation of the zero sound
by an electron beam is discussed and found that the quantization of the energy
of electrons imposes a new condition. Furthermore, the excitation of
Bogolyubov's type of spectrum by a strong electric field is considered.
\\ ( http://arxiv.org/abs/1005.3408 , 8kb)
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\\
arXiv:1005.3541
Date: Wed, 19 May 2010 20:00:36 GMT (36kb)
Title: Nonlinear resonant tunneling of Bose-Einstein condensates in tilted
optical lattices
Authors: K. Rapedius, C. Elsen, D. Witthaut, S. Wimberger, and H. J. Korsch
Categories: cond-mat.quant-gas quant-ph
Comments: 4 pages, 4 figures
\\
We study the tunneling decay of a Bose-Einstein condensate out of tilted
optical lattices within the mean-field approximation. We introduce a novel
method to calculate the resonance eigenstates of the Gross-Pitaevskii equation,
based on a grid relaxation procedure with complex absorbing potentials. This
algorithm works efficiently in a wide range of parameters where established
methods fail. It allows us to study the effects of the nonlinearity in detail
in the regime of resonant tunneling, where the decay rate is enhanced by
resonant coupling to excited unstable states.
\\ ( http://arxiv.org/abs/1005.3541 , 36kb)
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\\
arXiv:1005.3557
Date: Wed, 19 May 2010 20:48:28 GMT (86kb)
Title: Observing Monopoles in a Magnetic Analog of Ice
Authors: Michel J.P. Gingras
Categories: cond-mat.other
Comments: 3 pages, 1 figure
Journal-ref: Science 326, 375 (2009)
DOI: 10.1126/science.1181510
\\
This is a nontechnical Perspective commentary on two recent neutron
scattering experiments (Science 326, 415 (2009) and Science 326, 411 (2009))
reporting evidence for the validity of a "Coulomb phase" description of the
low-temperature regime of frustrated spin ice magnetic materials as well as the
existence of topological defect (monopole-like) excitations in these systems.
\\ ( http://arxiv.org/abs/1005.3557 , 86kb)
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\\
arXiv:1005.3576
Date: Thu, 20 May 2010 01:50:28 GMT (153kb)
Title: Thermodynamic properties of two-component fermionic atoms trapped in a
two-dimensional optical lattice
Authors: Kensuke Inaba and Makoto Yamashita
Categories: cond-mat.quant-gas
Comments: 9 pages, 13 figures
\\
We study the finite temperature properties of two-component fermionic atoms
trapped in a two-dimensional optical lattice. We apply the self-energy
functional approach to the two-dimensional Hubbard model with a harmonic
trapping potential, and systematically investigate the thermodynamic properties
of this system. We find that entropy and grand potential provide evidence of a
crossover between the Mott insulating and metallic phases at certain
temperatures. In addition, we find that entropy exhibits a cusp-like anomaly at
lower temperatures, suggesting a second or higher order antiferromagnetic
transition. We estimate the antiferromagnetic transition temperatures, and
clarify how the trapping potential affects this magnetic transition.
\\ ( http://arxiv.org/abs/1005.3576 , 153kb)
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\\
arXiv:1005.3628
Date: Thu, 20 May 2010 08:39:11 GMT (48kb)
Title: When a DNA Triple helix melts: An analog of the Efimov state
Authors: Jaya Maji, Somendra M. Bhattacharjee, Flavio Seno and A. Trovatto
Categories: cond-mat.soft cond-mat.stat-mech nucl-th
Comments: 7 pages, 8 figures
\\
The base sequences of DNA contain the genetic code and to decode it a double
helical DNA has to open its base pairs. Last several years' studies have shown
that one can use a third strand to identify the base sequences without opening
the double helix but by forming a triple helix. It is predicted here that such
a three chain system exhibits the unusual behaviour of the existence of a three
chain bound state in the absence of any two being bound. This phenomenon is
analogous to the Efimov state in three particle quantum mechanics. A scaling
theory is used to justify the Efimov connection. Real space renormalization
group (RG), and exact numerical calculations are used to validate the
prediction of a biological Efimov effect.
\\ ( http://arxiv.org/abs/1005.3628 , 48kb)
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\\
arXiv:1005.3641
Date: Thu, 20 May 2010 09:37:30 GMT (110kb)
Title: Correlations and superfluidity of a one-dimensional Bose gas in a
quasiperiodic potential
Authors: Alberto Cetoli and Emil Lundh
Categories: cond-mat.dis-nn
Comments: Accepted for publication in PRA
\\
We consider the correlations and superfluid properties of a Bose gas in an
external potential. Using a Bogoliubov scheme, we obtain expressions for the
correlation function and the superfluid density in an arbitrary external
potential. These expressions are applied to a one-dimensional system at zero
temperature subject to a quasiperiodic modulation. The critical parameters for
the Bose glass transition are obtained using two different criteria and the
results are compared. The Lifshits glass is seen to be the limiting case for
vanishing interactions.
\\ ( http://arxiv.org/abs/1005.3641 , 110kb)
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\\
arXiv:1005.3660
Date: Thu, 20 May 2010 11:16:42 GMT (164kb)
Title: Lieb-Liniger gas in a constant force potential
Authors: D. Juki\'c, S. Gali\'c, R. Pezer, H. Buljan
Categories: cond-mat.quant-gas quant-ph
\\
We use Gaudin's Fermi-Bose mapping operator to calculate exact solutions for
the Lieb-Liniger model in a linear (constant force) potential (the constructed
exact stationary solutions are referred to as the Lieb-Liniger-Airy wave
functions). The ground state properties of the gas in the wedge-like trapping
potential are calculated in the strongly interacting regime by using
Girardeau's Fermi-Bose mapping and the pseudopotential approach in the
$1/c$-approximation ($c$ denotes the strength of the interaction). We point out
that quantum dynamics of Lieb-Liniger wave packets in the linear potential can
be calculated by employing an $N$-dimensional Fourier transform as in the case
of free expansion.
\\ ( http://arxiv.org/abs/1005.3660 , 164kb)
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\\
arXiv:1005.3670
Date: Thu, 20 May 2010 11:49:46 GMT (781kb)
Title: Realization of SU(2)*SU(6) Fermi System
Authors: Shintaro Taie, Yosuke Takasu, Seiji Sugawa, Rekishu Yamazaki, Takuya
Tsujimoto, Ryo Murakami, Yoshiro Takahashi
Categories: cond-mat.quant-gas physics.atom-ph
Comments: 4 pages, 5 figures
\\
We report the realization of a novel degenerate Fermi mixture with an
SU(2)*SU(6) symmetry in a cold atomic gas. We successfully cool the mixture of
the two fermionic isotopes of ytterbium 171Yb with the nuclear spin I=1/2 and
173Yb with I=5/2 below the Fermi temperature T_ F as 0.46T_F for 171Yb and
0.54T_F for 173Yb. The same scattering lengths for different spin components
make this mixture featured with the novel SU(2)*SU(6) symmetry. The nuclear
spin components are separately imaged by exploiting an optical Stern-Gerlach
effect. In addition, the mixture is loaded into a 3D optical lattice to
implement the SU(2)*SU(6) Hubbard model. This mixture will open the door to the
study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like
fermionic superfluid.
\\ ( http://arxiv.org/abs/1005.3670 , 781kb)
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\\
arXiv:1005.3725
Date: Thu, 20 May 2010 15:01:46 GMT (608kb)
Title: Off-axis Vortex in a Rotating Dipolar Bose-Einstein Condensation
Authors: C. Yuce, Z. Oztas
Categories: cond-mat.quant-gas
Comments: Journal of Physics B (to be published); 9 pages; 6 Figures
\\
We consider a singly quantized off-axis straight vortex in a rotating dipolar
ultracold gas in the Thomas-Fermi (TF) regime. We derive analytic results for
small displacements and perform numerical calculations for large displacement
within the TF regime. We show that the dipolar interaction energy increases
(decreases) as the vortex moves from the trap center to the edge in an oblate
(a prolate) trap. We find that for an oblate (a prolate) trap, the effect of
the dipole-dipole interaction is to lower (raise) both the precession velocity
of an off-center straight vortex line and the angular velocity representing the
onset of metastability.
\\ ( http://arxiv.org/abs/1005.3725 , 608kb)
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\\
arXiv:1005.3789
Date: Thu, 20 May 2010 18:55:29 GMT (2959kb)
Title: Dynamics of Dark-Bright Solitons in Cigar-Shaped Bose-Einstein
Condensates
Authors: S. Middelkamp, J.J. Chang, C. Hamner, R. Carretero-Gonzalez, P.G.
Kevrekidis, V. Achilleos, D.J. Frantzeskakis, P. Schmelcher, P. Engels
Categories: cond-mat.quant-gas
Comments: 4 pages, 5 figures
\\
We explore the stability and dynamics of dark-bright solitons in
two-component elongated Bose-Einstein condensates by developing effective 1D
vector equations as well as solving the corresponding 3D Gross-Pitaevskii
equations. A strong dependence of the oscillation frequency and of the
stability of the dark-bright (DB) soliton on the atom number of its components
is found. Spontaneous symmetry breaking leads to oscillatory dynamics in the
transverse degrees of freedom for a large occupation of the component
supporting the dark soliton. Moreover, the interactions of two DB solitons are
investigated with special emphasis on the importance of their relative phases.
Experimental results showcasing dark-bright soliton dynamics and collisions in
a BEC consisting of two hyperfine states of $^{87}$Rb confined in an elongated
optical dipole trap are presented.
\\ ( http://arxiv.org/abs/1005.3789 , 2959kb)
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The replacements:
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\\
arXiv:0904.3221
replaced with revised version Tue, 18 May 2010 10:06:59 GMT (197kb)
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: 27 pages, 7 figures, minor corrections, refs added
Journal-ref: J. Stat. Mech. (2010) P05012
DOI: 10.1088/1742-5468/2010/05/P05012
\\ ( http://arxiv.org/abs/0904.3221 , 197kb)
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\\
arXiv:0907.2906
replaced with revised version Mon, 17 May 2010 19:54:23 GMT (882kb)
Title: Anharmonicity Induced Resonances for Ultracold Atoms and their Detection
Authors: J. P. Kestner, L.-M. Duan
Categories: cond-mat.quant-gas
Comments: 6 pages, 5 figures; expanded presentation
Journal-ref: New J. Phys. 12, 053016 (2010)
DOI: 10.1088/1367-2630/12/5/053016
\\ ( http://arxiv.org/abs/0907.2906 , 882kb)
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\\
arXiv:0910.1749 (*cross-listing*)
replaced with revised version Fri, 14 May 2010 13:48:33 GMT (187kb)
Title: Fermionization dynamics of a strongly interacting 1D Bose gas after an
interaction quench
Authors: Dominik Muth, Bernd Schmidt, and Michael Fleischhauer
Categories: quant-ph cond-mat.quant-gas
Comments: 10 pages, 4 figures
\\ ( http://arxiv.org/abs/0910.1749 , 187kb)
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\\
arXiv:0910.1859
replaced with revised version Fri, 14 May 2010 08:02:16 GMT (622kb,D)
Title: Observability of Quantum Criticality and a Continuous Supersolid in
Atomic Gases
Authors: S. Diehl, M. Baranov, A. J. Daley, P. Zoller
Categories: cond-mat.quant-gas
Comments: 4 pages, 2 figures, published version (Editor's suggestion)
Journal-ref: Phys. Rev. Lett. 104, 165301 (2010)
DOI: 10.1103/PhysRevLett.104.165301
\\ ( http://arxiv.org/abs/0910.1859 , 622kb)
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\\
arXiv:0912.3502
replaced with revised version Thu, 20 May 2010 15:22:34 GMT (87kb,D)
Title: 1D Lieb-Liniger Bose Gas as Non-Relativistic Limit of the Sinh-Gordon
Model
Authors: M. Kormos, G. Mussardo, A. Trombettoni
Categories: cond-mat.stat-mech cond-mat.quant-gas hep-th
Comments: published version, 27 pages, 10 figures
Journal-ref: Phys.Rev.A81:043606,2010
DOI: 10.1103/PhysRevA.81.043606
\\ ( http://arxiv.org/abs/0912.3502 , 87kb)
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\\
arXiv:1002.0552
replaced with revised version Thu, 20 May 2010 07:35:44 GMT (622kb)
Title: Dark solitons in cigar-shaped Bose-Einstein condensates in double-well
potentials
Authors: S. Middelkamp, G. Theocharis, P.G. Kevrekidis, D.J. Frantzeskakis, P.
Schmelcher
Categories: cond-mat.quant-gas
Comments: 35 pages, 12 figures
Journal-ref: Phys. Rev. A 81, 053618 (2010)
DOI: 10.1103/PhysRevA.81.053618
\\ ( http://arxiv.org/abs/1002.0552 , 622kb)
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\\
arXiv:1003.0387
replaced with revised version Thu, 20 May 2010 02:00:45 GMT (1528kb)
Title: Vortex dynamics in superconducting channels with periodic constrictions
Authors: K. Yu (1), M.B.S. Hesselberth (2), P.H. Kes (2), B.L.T. Plourde (1)
((1) Department of Physics, Syracuse University, (2) Kamerlingh Onnes
Laboratorium, Leiden University)
Categories: cond-mat.supr-con
Journal-ref: Phys. Rev. B 81, 184503 (2010)
DOI: 10.1103/PhysRevB.81.184503
\\ ( http://arxiv.org/abs/1003.0387 , 1528kb)
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\\
arXiv:1004.1966
replaced with revised version Tue, 18 May 2010 09:45:37 GMT (152kb,D)
Title: Influence of the particle number on the spin dynamics of ultracold atoms
Authors: Jannes Heinze, Frank Deuretzbacher and Daniela Pfannkuche
Categories: cond-mat.quant-gas
\\ ( http://arxiv.org/abs/1004.1966 , 152kb)
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\\
arXiv:1004.3969
replaced with revised version Thu, 20 May 2010 14:48:46 GMT (192kb)
Title: EIT-based Vector Magnetometry in Linear Polarized Light
Authors: V. I. Yudin, A. V. Taichenachev, Y. I. Dudin, V. L. Velichansky, A. S.
Zibrov, S. A. Zibrov
Categories: physics.atom-ph physics.ins-det quant-ph
Comments: 8 pages, 7 figures
\\ ( http://arxiv.org/abs/1004.3969 , 192kb)
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\\
arXiv:1005.1812
replaced with revised version Tue, 18 May 2010 09:19:32 GMT (0kb,I)
Title: Absence of pairing in atomic Fermi gases
Authors: J. J. Kinnunen
Categories: cond-mat.quant-gas quant-ph
Comments: The draft paper has been withdrawn by the author
\\ ( http://arxiv.org/abs/1005.1812 , 0kb)
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\\
arXiv:1005.2403
replaced with revised version Fri, 14 May 2010 17:42:50 GMT (477kb,D)
Title: A superfluid-droplet crystal and a free-space supersolid in a
dipole-blockaded gas
Authors: F. Cinti, P. Jain, M. Boninsegni, A. Micheli, P. Zoller, and G.
Pupillo
Categories: cond-mat.quant-gas cond-mat.stat-mech
Comments: 4 pages, 4 figures
\\ ( http://arxiv.org/abs/1005.2403 , 477kb)
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\\
arXiv:cond-mat/0703498
replaced with revised version Wed, 19 May 2010 05:23:56 GMT (98kb)
Title: Re-examining Bogoliubov's theory of an interacting Bose gas
Authors: A.M. Ettouhami
Categories: cond-mat.stat-mech cond-mat.other cond-mat.quant-gas
Comments: Major revision of version 1; 41 pages, 16 figures
\\ ( http://arxiv.org/abs/cond-mat/0703498 , 98kb)
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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/
=========================================================================
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http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/
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