# Matt's arXiV selection, Friday 9th December 2005

From: Matthew Davis <mdavis_at_physics.uq.edu.au>
Date: Fri, 9 Dec 2005 17:19:33 +1000 (EST)

Hi everyone,

I'm going to try and start a new service: a filtering of recent papers
from arxiv.org, mainly in the area of ultracold quantum gases (but also
anything else that takes my fancy) from the recent submissions to the
cond-mat, quant-ph, and physics arxivs. Hopefully I will send it on a
weekly basis. I will probably start a mailing list for this: in the
meantime BECjournal will do.

Enjoy,
Matt.

--
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Dr M. J. Davis,               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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Paper: cond-mat/0512007
Date: Thu, 1 Dec 2005 17:06:34 GMT   (114kb)
Title: Instability of a superfluid Bose gas induced by a locked thermal gas in
an optical lattice
Authors: Satoru Konabe and Tetsuro Nikuni
Subj-class: Other
\\
We use a dissipative Gross-Petaevskii equation derived from the Bose-Hubbard
Hamiltonian to study the effect of the thermal component on the stability of a
current-carrying superfluid state of a Bose gas in an optical lattice
potential. We explicitly show that the superfluid state becomes unstable at
certain quasi-momentum of the condensate due to a thermal component which is
locked by an optical lattice potential. It is shown that this instability
coincides with the Landau instability derived from the GP equation.
\\ ( http://arXiv.org/abs/cond-mat/0512007 ,  114kb)
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Paper: cond-mat/0512010
Date: Thu, 1 Dec 2005 19:11:02 GMT   (421kb)
Title: Sound velocity and dimensional crossover in a superfluid Fermi gas in an
optical lattice
Authors: T. Koponen, J.-P. Martikainen, J. Kinnunen, and P. Torma
Subj-class: Superconductivity
\\
We study the density response and the sound velocity in isotropic and
anisotropic three-dimensional optical lattices. We show how the van Hove
singularity of the free Fermi gas is smoothened by interactions and eventually
vanishes when interactions are strong enough. For anisotropic lattices, we show
that the speed of sound shows clear signatures of dimensional crossover both in
the 1D and 2D limits.
\\ ( http://arXiv.org/abs/cond-mat/0512010 ,  421kb)
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Paper: cond-mat/0512018
Date: Thu, 1 Dec 2005 14:19:51 GMT   (587kb)
Title: Fourier Synthesis of Conservative Atom Potentials
Authors: Gunnar Ritt, Carsten Geckeler, Tobias Salger, Giovanni Cennini, Martin
Weitz
Subj-class: Other
\\
We demonstrate a scheme for the Fourier synthesis of conservative optical
potentials for atoms. An atomic Bose-Einstein condensate is exposed to either
symmetric or sawtooth-like asymmetric potentials by superimposing a
conventional standing wave potential of $\lambda / 2$ spatial periodicity with
a fourth-order lattice potential of $\lambda / 4$ periodicity. The high
periodicity lattice is realized with a Doppler-sensitive multiphoton Raman
process. A suitable combination of laser frequencies suppresses unwanted
standing wave effects. Future applications of the demonstrated scheme could
include dissipationless atomic quantum ratchets.
\\ ( http://arXiv.org/abs/cond-mat/0512018 ,  587kb)
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Paper: cond-mat/0512023
Date: Thu, 1 Dec 2005 15:59:23 GMT   (217kb)
Title: Bose-Einstein condensation vs. localization of bosonic quasiparticles in
disordered weakly-coupled dimer antiferromagnets
Authors: Tommaso Roscilde, Stephan Haas
Comments: 12 pages, 4 figures. Contribution to the BEC Cortona Workshop 2005
Subj-class: Strongly Correlated Electrons; Disordered Systems and Neural
Networks
\\
We investigate the field-induced insulator-to-superfluid transition of
bosonic quasiparticles in $S=1/2$ weakly-coupled dimer antiferromagnets. In
presence of realistic disorder due to site dilution of the magnetic lattice, we
show that the system displays an extended Bose-glass phase characterized by the
localization of the hard-core quasiparticles.
\\ ( http://arXiv.org/abs/cond-mat/0512023 ,  217kb)
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Paper: cond-mat/0512031
Date: Thu, 1 Dec 2005 20:07:04 GMT   (70kb)
Title: Interaction-Induced Localization of an Impurity in a Trapped Bose
Condensate
Authors: Ryan M. Kalas and D. Blume
Subj-class: Other
\\
We study the ground state properties of a trapped Bose condensate with a
neutral impurity. By varying the strength of the attractive atom-impurity
interactions the degree of localization of the impurity at the trap center can
be controlled. As the impurity becomes more strongly localized the peak
condensate density, which can be monitored experimentally, grows markedly. For
strong enough attraction, the impurity can make the condensate unstable by
strongly deforming the atom density in the neighborhood of the impurity. This
"collapse" can possibly be investigated in bosenova-type experiments.
\\ ( http://arXiv.org/abs/cond-mat/0512031 ,  70kb)
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Paper (*cross-listing*): physics/0511239
Date: Mon, 28 Nov 2005 21:27:09 GMT   (287kb)
Date (revised v2): Wed, 30 Nov 2005 15:39:08 GMT   (287kb)
Title: Coupled dynamics of atoms and radiation pressure driven interferometers
Authors: D. Meiser and P. Meystre
Subj-class: Atomic Physics; Optics; Other
\\
We consider the motion of the end mirror of a cavity in whose standing wave
mode pattern atoms are trapped. The atoms and the light field strongly couple
to each other because the atoms form a distributed Bragg mirror with a
reflectivity that can be fairly high. We analyze how the dipole potential in
which the atoms move is modified due to this backaction of the atoms. We show
that the position of the atoms can become bistable. These results are of a more
general nature and can be applied to any situation where atoms are trapped in
an optical lattice inside a cavity and where the backaction of the atoms on the
light field cannot be neglected. We analyze the dynamics of the coupled system
in the adiabatic limit where the light field adjusts to the position of the
atoms and the light field instantaneously and where the atoms move much faster
than the mirror. We calculate the side band spectrum of the light transmitted
through the cavity and show that these spectra can be used to detect the
coupled motion of the atoms and the mirror.
\\ ( http://arXiv.org/abs/physics/0511239 ,  287kb)
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Paper: cond-mat/0509776
replaced with revised version Thu, 1 Dec 2005 18:34:17 GMT   (151kb)
Title: The Population Oscillation of Multicomponent Spinor Bose-Einstein
Authors: Xiuquan Ma, Lin Xia, Fang Yang, Xiaoji Zhou, Yiqiu Wang, Hong Guo, and
Xuzong Chen
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0509776 ,  151kb)
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Paper: cond-mat/0508195
replaced with revised version Thu, 1 Dec 2005 18:23:47 GMT   (59kb)
Title: Velocity of vortices in inhomogeneous Bose-Einstein condensates
Authors: Halvor M. Nilsen, Gordon Baym, and C. J. Pethick
Comments: 4 pages, one .eps figure Change of title. Improved presentation of
physics
Report-no: NORDITA-2005-51
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0508195 ,  59kb)
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Paper: cond-mat/0512048
Date: Fri, 2 Dec 2005 12:32:52 GMT   (77kb)
Title: Molecular signatures in the structure factor of an interacting Fermi gas
Authors: R. Combescot, S. Giorgini, S. Stringari
Subj-class: Other
\\
The static and dynamic structure factors of an interacting Fermi gas along
the BCS-BEC crossover are calculated at momentum transfer $\hbar{\bf k}$ higher
than the Fermi momentum. The spin structure factor is found to be very
sensitive to the correlations associated with the formation of molecules. On
the BEC side of the crossover, even close to unitarity, clear evidence is found
for a molecular excitation at $\hbar^2 k^2 /4m$, where $m$ is the atomic mass.
Both quantum Monte Carlo and dynamic mean-field results are presented.
\\ ( http://arXiv.org/abs/cond-mat/0512048 ,  77kb)
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Paper: cond-mat/0511641
replaced with revised version Fri, 2 Dec 2005 19:49:45 GMT   (40kb)
Title: Quantum criticality of a Fermi gas with a spherical dispersion minimum
Authors: Kun Yang and Subir Sachdev
Subj-class: Strongly Correlated Electrons; Superconductivity
\\ ( http://arXiv.org/abs/cond-mat/0511641 ,  40kb)
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Paper: cond-mat/0512082
Date: Mon, 5 Dec 2005 11:11:29 GMT   (392kb)
Title: Elastic scattering losses from colliding BEC's
Authors: Pawel Zin, Jan Chwedenczuk and Marek Trippenbach
Subj-class: Other
\\
Bragg diffraction divides a Bose-Einstein condensate into two overlapping
components, moving with respect to each other with high momentum. Elastic
collisions between atoms from distinct wave packets can significantly deplete
the condensate. Recently Zi\'{n} {\it et al.} (Phys. Rev. Lett. {\bf 94},
200401 (2005)) have introduced a model of two counter-propagating atomic
Gaussian wavepackets incorporating dynamics of the incoherent scattering
processes. Here we study the properties of this model in detail, including the
nature of the transition from spontaneous to stimulated scattering. Within the
first order approximation we derive analytical expressions for the density
matrix and anomalous density which provides excellent insight into correlation
properties of scattered atoms.
\\ ( http://arXiv.org/abs/cond-mat/0512082 ,  392kb)
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Paper: quant-ph/0512006
Date: Thu, 1 Dec 2005 11:29:25 GMT   (366kb)
Title: Time-resolved and state-selective detection of single freely falling
atoms
Authors: Torsten Bondo, Markus Hennrich, Thomas Legero, Gerhard Rempe, and Axel
Kuhn
\\
We report on the detection of single, slowly moving Rubidium atoms using
laser-induced fluorescence. The atoms move at 3 m/s while they are detected
with a time resolution of 60 microseconds. The detection scheme employs a
near-resonant laser beam that drives a cycling atomic transition, and a highly
efficient mirror setup to focus a large fraction of the fluorescence photons to
a photomultiplier tube. It counts on average 20 photons per atom.
\\ ( http://arXiv.org/abs/quant-ph/0512006 ,  366kb)
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Paper (*cross-listing*): nlin.CD/0512002
Date: Thu, 1 Dec 2005 14:14:49 GMT   (504kb)
Title: Can quantum fractal fluctuations be observed in an atom-optics kicked
rotor experiment?
Authors: Andrea Tomadin, Riccardo Mannella, and Sandro Wimberger
Comments: 18 pp, 7 figs., 1 table
Subj-class: Chaotic Dynamics
\\
We investigate the parametric fluctuations in the quantum survival
probability of an open version of the delta-kicked rotor model in the deep
quantum regime. Spectral arguments [Guarneri I and Terraneo M 2001 Phys. Rev. E
vol. 65 015203(R)] predict the existence of parametric fractal fluctuations
owing to the strong dynamical localisation of the eigenstates of the kicked
rotor. We discuss the possibility of observing such dynamically-induced
fractality in the quantum survival probability as a function of the kicking
period for the atom-optics realisation of the kicked rotor. The influence of
the atoms' initial momentum distribution is studied as well as the dependence
of the expected fractal dimension on finite-size effects of the experiment,
such as finite detection windows and short measurement times. Our results show
that clear signatures of fractality could be observed in experiments with cold
atoms subjected to periodically flashed optical lattices, which offer an
excellent control on interaction times and the initial atomic ensemble.
\\ ( http://arXiv.org/abs/nlin/0512002 ,  504kb)
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Paper: quant-ph/0512043
Date: Tue, 6 Dec 2005 12:53:21 GMT   (36kb)
Title: Exploring surface interactions with atom chips
Authors: Carsten Henkel
\\
We review the current status of the field of atom-surface interactions, with
an emphasis on the regimes specific to atom chips. Recent developments in
theory and experiment are highlighted. In particular, atom-surface interactions
define physical limits for miniaturization and coherent operation. This implies
constraints for applications in quantum information processing or matter wave
interferometry. We focus on atom-surface interaction potentials induced by
vacuum fluctuations (Van der Waals and Casimir-Polder forces), and on
transitions between atomic quantum states that are induced by thermally excited
magnetic near fields. Open questions and current challenges are sketched.
\\ ( http://arXiv.org/abs/quant-ph/0512043 ,  36kb)
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Paper: physics/0512041
Date: Tue, 6 Dec 2005 08:07:44 GMT   (41kb)
Title: Self-sustained oscillations in a Large Magneto-Optical Trap
Authors: Guillaume Labeyrie (INLN), Franck Michaud (INLN), Robin Kaiser (INLN)
Comments: submitted to Phys. Rev. Lett. 4 pages, 3 figures
Proxy: ccsd ccsd-00015277
Subj-class: Atomic Physics; Plasma Physics
\\
We have observed self-sustained radial oscillations in a large
magneto-optical trap (MOT), containing up to $10^{10}$ Rb$^{85}$ atoms. This
instability is due to the competition between the confining force of the MOT
and the repulsive interaction associated with multiple scattering of light
inside the cold atomic cloud. A simple analytical model allows us to formulate
a criterion for the instability threshold, in fair agreement with our
observations. This criterion shows that large numbers of trapped atoms $N>10^9$
are required to observe this unstable behavior.
\\ ( http://arXiv.org/abs/physics/0512041 ,  41kb)
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Paper: cond-mat/0512134
Date: Wed, 7 Dec 2005 00:08:01 GMT   (31kb)
Title: Acoustic attenuation probe for fermion superfluidity in ultracold atom
gases
Authors: Sergio Gaudio (1)(2), B. Mihaila (2), K. B. Blagoev (2), K. S. Bedell
(1), Eddy Timmermans (2) (1) (Department of Physics, Boston College) (2)
(Theoretical Division, Los Alamos Natl Labs)
Comments: 5 pages, 2 figures. submitted to PRL
Report-no: LAUR-05-3432
Subj-class: Other
\\
Dilute gas Bose-Einstein condensates (BEC's), currently used to cool
fermionic atoms in atom traps, can also probe the superfluidity of these
fermions. The damping rate of BEC-acoustic excitations (phonon modes), measured
in the middle of the trap as a function of the phonon momentum, yields an
unambiguous signature of BCS-like superfluidity, provides a measurement of the
superfluid gap parameter and gives an estimate of the size of the Cooper-pairs
in the BEC-BCS crossover regime. We also predict kinks in the momentum
dependence of the damping rate which can reveal detailed information about the
fermion quasi-particle dispersion relation.
\\ ( http://arXiv.org/abs/cond-mat/0512134 ,  31kb)
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Paper (*cross-listing*): physics/0512033
Date: Mon, 5 Dec 2005 16:13:07 GMT   (33kb)
Title: One-dimensional Bose chemistry: effects of non-integrability
Authors: V. A. Yurovsky (1), A. Ben-Reuven (1) and M. Olshanii (2) ((1)
Tel-Aviv University, (2)University of Southern California)
Subj-class: Atomic Physics; Soft Condensed Matter
\\
Three-body collisions of ultracold identical Bose atoms under tight
cylindrical confinement are analyzed. A Feshbach resonance in two-body
collisions is described by a two-channel zero-range interaction. Elimination of
the closed channel in the three-body problem reduces the interaction to a
one-channel zero-range one with an energy dependent strength. The related
problem with an energy independent strength (the Lieb-Liniger-McGuire model)
has an exact solution and forbids all chemical processes, such as three-atom
association and diatom dissociation, as well as reflection in atom-diatom
collisions. The resonant case is analyzed by a numerical solution of the
Faddeev-Lovelace equations. The results demonstrate that as the internal
symmetry of the Lieb-Liniger-McGuire model is lifted, the reflection and
chemical reactions become allowed and may be observed in experiments.
\\ ( http://arXiv.org/abs/physics/0512033 ,  33kb)
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Paper: cond-mat/0505697
replaced with revised version Wed, 7 Dec 2005 06:42:52 GMT   (94kb)
Title: Enhanced Quantum Reflection of Matter-Wave Solitons
Authors: Chaohong Lee and Joachim Brand
Comments: 7 pages, 3 figures, to be published in Europhys. Lett
Subj-class: Other; Pattern Formation and Solitons
\\ ( http://arXiv.org/abs/cond-mat/0505697 ,  94kb)
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Paper: cond-mat/0506419
replaced with revised version Wed, 7 Dec 2005 00:26:39 GMT   (93kb)
Title: Finite-temperature properties of hard-core bosons confined on
one-dimensional optical lattices
Authors: Marcos Rigol
Comments: RevTex file, 12 pages, 16 figures, published version
Subj-class: Statistical Mechanics; Other
Journal-ref: Phys. Rev. A 72, 063607 (2005)
DOI: 10.1103/PhysRevA.72.063607
\\ ( http://arXiv.org/abs/cond-mat/0506419 ,  93kb)
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Paper: cond-mat/0507391
replaced with revised version Wed, 7 Dec 2005 10:07:27 GMT   (31kb)
Title: Expansion of the Gibbs potential for quantum many-body systems: General
formalism with applications to the spin glass and the weakly non-ideal Bose
gas
Authors: T. Plefka
Comments: 17 pages, 0 figures; revised version accepted by Phys Rev E
Subj-class: Statistical Mechanics; Disordered Systems and Neural Networks
\\ ( http://arXiv.org/abs/cond-mat/0507391 ,  31kb)
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Paper: cond-mat/0509560
replaced with revised version Tue, 6 Dec 2005 21:59:27 GMT   (64kb)
Title: Phase coherence, visibility, and the superfluid--Mott-insulator
transition on one-dimensional optical lattices
Authors: P. Sengupta, M. Rigol, G. G. Batrouni, P. J. H. Denteneer, R. T.
Scalettar
Subj-class: Other
Journal-ref: Phys. Rev. Lett. 95, 220402 (2005)
\\ ( http://arXiv.org/abs/cond-mat/0509560 ,  64kb)
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Paper: quant-ph/0512056
Date: Wed, 7 Dec 2005 12:17:22 GMT   (102kb)
Title: Paramagnetic Faraday rotation with spin-polarized ytterbium atoms
Authors: M. Takeuchi, T. Takano, S. Ichihara, Y. Takasu, M. Kumakura, T.
Yabuzaki and Y. Takahashi
\\
We report observation of the paramagnetic Faraday rotation of spin-polarized
ytterbium (Yb) atoms. As the sample of the atoms, we used atomic beam, released
atom from magneto-optical trap (MOT), and trapped atoms in far-off-resonant
trap (FORT). Since Yb is diamagnetic and has spin-1/2 isotope, it is an ideal
sample for the spin physics, such as quantum non-demolition measurement of spin
(spin QND), for example. From the results of the rotation angle, we confirmed
that the atoms were almost perfectly polarized.
\\ ( http://arXiv.org/abs/quant-ph/0512056 ,  102kb)
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Paper: physics/0512065
Date: Wed, 7 Dec 2005 20:54:18 GMT   (71kb)
Title: Laser cooling of new atomic and molecular species with ultrafast pulses
Authors: D. Kielpinski
Comments: revision of quant-ph/0306099, submitted to PRA
Subj-class: Atomic Physics
\\
We propose a new laser cooling method for atomic species whose level
structure makes traditional laser cooling difficult. For instance, laser
cooling of hydrogen requires single-frequency vacuum-ultraviolet light, while
multielectron atoms need single-frequency light at many widely separated
frequencies. These restrictions can be eased by laser cooling on two-photon
transitions with ultrafast pulse trains. Laser cooling of hydrogen,
antihydrogen, and many other species appears feasible, and extension of the
technique to molecules may be possible.
\\ ( http://arXiv.org/abs/physics/0512065 ,  71kb)
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Paper: cond-mat/0512169
Date: Thu, 8 Dec 2005 08:50:23 GMT   (453kb)
Title: A new class of exact solitary wave solutions of one dimensional
Gross-Pitaevskii equation
Authors: Rajneesh Atre, Prasanta K. Panigrahi and G.S. Agarwal
Comments: 4 pages, 4 eps figures
Subj-class: Other
\\
We present a large family of {\it{exact}} solitary wave solutions of the one
dimensional Gross-Pitaevskii equation, with time-varying scattering length and
gain/loss, in both expulsive and regular parabolic confinement regimes. The
consistency condition governing the soliton profiles is shown to map on to a
{\it{linear}} Schr\"odinger eigenvalue problem, thereby enabling one to find
analytically the effect of a wide variety of temporal variations in the control
parameters, which are experimentally realizable. Corresponding to each solvable
quantum mechanical system, one can identify a soliton configuration. These
include soliton trains in close analogy to experimental observations of
Strecker {\it{et al.,}} [Nature {\bf{{417}}{150}{2002}], spatio-temporal
dynamics, solitons undergoing rapid amplification, collapse and revival of
condensates and analytical expression of two-soliton bound states, to name a
few.
\\ ( http://arXiv.org/abs/cond-mat/0512169 ,  453kb)
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Paper: cond-mat/0508326
replaced with revised version Wed, 7 Dec 2005 22:24:29 GMT   (407kb)
Title: Bragg Spectroscopy of Vortex Lattices in Bose-Einstein condensates
Authors: S. R. Muniz, D. S. Naik and C. Raman
Comments: 5 pages, 5 Figures, A movie built from the CM data is available in
presents new data, showing signatures of the microscopic vortex structure in
the diffracted cloud
Subj-class: Other
\\ ( http://arXiv.org/abs/cond-mat/0508326 ,  407kb)
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Paper: quant-ph/0512061
Date: Thu, 8 Dec 2005 08:18:32 GMT   (178kb)
Title: Highly versatile atomic micro traps generated by multifrequency magnetic
field modulation
Authors: Ph.W. Courteille, B. Deh, J. Fort\'agh, A. G\"unther, S. Kraft, C.
Marzok, S. Slama, and C. Zimmermann
\\
We propose the realization of custom-designed adiabatic potentials for cold
inhomogeneous magnetic fields. For example, the use of radio frequency combs
gives rise to periodic potentials acting as gratings for cold atoms. In strong
magnetic field gradients the lattice constant can be well below 1 micrometer.
By changing the frequencies of the comb in time the gratings can easily be
propagated in space, which may prove useful for Bragg scattering atomic matter
waves. Furthermore, almost arbitrarily shaped potential are possible such as
disordered potentials on a scale of several 100 nm or lattices with a spatially
varying lattice constant. The potentials can be made state selective and, in
the case of atomic mixtures, also species selective. This opens new
perspectives for generating tailored quantum systems based on ultra cold single
atoms or degenerate atomic and molecular quantum gases.
\\ ( http://arXiv.org/abs/quant-ph/0512061 ,  178kb)
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Received on Fri Dec 09 2005 - 17:19:33 EST

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