The following message was sent to the matts_arxiv list by Matthew Davis <mdavis_at_physics.uq.edu.au>
Hi all,
This week there were 23 new preprints and 7 replacements:
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arXiv:0810.5625
Date: Fri, 31 Oct 2008 06:25:59 GMT (57kb)
Title: Finite-frequency dynamics of vortex loops at the $^4$He superfluid phase
transition
Authors: Gary A. Williams
Categories: cond-mat.stat-mech
Comments: 4 pages, submitted to Journal of Physics: Conference Series
(Proceedings of LT25)
\\
The finite-frequency dynamics of the $^4$He superfluid phase transition can
be formulated in terms of the response of thermally excited vortex loops to an
oscillating flow field. The key parameter is the Hausdorff fractal dimension
$d_H$ of the loops, which affects the dynamics because the frictional force on
a loop is proportional to the total perimeter $P$ of the loop, which varies as
$P \sim a^{d_H}$ where $a$ is the loop diameter. Solving the 3D Fokker-Planck
equation for the loop response at frequency $\omega $ yields a superfluid
density which varies at $T_{\lambda}$ as $\omega^{1/(d_H -1)}$. This power-law
variation with $\omega$ agrees with the scaling form found by Fisher, Fisher,
and Huse, since the dynamic exponent $z$ is identified as $z = d_H-1$. Flory
scaling for the self-avoiding loops gives a fractal dimension in terms of the
space dimension $d$ as $d_H = (d+2)/2$, yielding $z = d/2 = 3/2$ for d = 3, in
complete agreement with dynamic scaling.
\\ ( http://arxiv.org/abs/0810.5625 , 57kb)
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arXiv:0810.5687
Date: Fri, 31 Oct 2008 13:46:56 GMT (334kb)
Title: Incoherence of Bose-Einstein condensates at supersonic speeds due to
quantum noise
Authors: R.G. Scott and D.A.W. Hutchinson
Categories: cond-mat.other
Comments: 6 pages, 5 figures
\\
We calculate the effect of quantum noise in supersonic transport of
Bose-Einstein condensates. When an obstacle obstructs the flow of atoms,
quantum fluctuations cause atoms to be scattered incoherently into random
directions. This suppresses the propagation of Cherenkov radiation, creating
quantum turbulence and a crescent of incoherent atoms around the obstacle. We
observe similar dynamics if the BEC is stirred by a laser beam: crescents of
incoherent atoms are emitted from the laser's turning-points. Finally, we
investigate supersonic flow through a disordered potential, and find that the
quantum fluctuations generate an accumulation of incoherent atoms as the
condensate enters the disorder.
\\ ( http://arxiv.org/abs/0810.5687 , 334kb)
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arXiv:0810.5690
Date: Fri, 31 Oct 2008 14:10:33 GMT (700kb)
Title: Rayleigh superradiance and dynamic Bragg gratings in an end-pumped
Bose-Einstein condensate
Authors: A. Hilliard, F. Kaminski, R. le Targat, C. Olausson, E. S. Polzik, and
J. H. M\"uller
Categories: cond-mat.other
Comments: 5 pages, 3 figures
\\
We study experimentally superradiant Rayleigh scattering from a Bose-Einstein
condensate (BEC) in a new parameter regime where pump depletion and the
exchange of photons between the endfire modes are important. Through
experiments and simulations we show that collective atom light coupling leads
to the self-organized formation of dynamic Bragg gratings within the sample.
These gratings lead to an efficient back-scattering of pump photons and optical
resonator structures within the BEC.
\\ ( http://arxiv.org/abs/0810.5690 , 700kb)
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arXiv:0810.5726
Date: Fri, 31 Oct 2008 16:16:49 GMT (68kb)
Title: Control of the persistent currents in two interacting quantum rings
through the Coulomb interaction and inter-ring tunneling
Authors: L. K. Castelano, G.-Q. Hai, B. Partoens and F. M. Peeters
Categories: cond-mat.mes-hall
Comments: accepted for publication in Phys. Rev. B
\\
The persistent current in two vertically coupled quantum rings containing few
electrons is studied. We find that the Coulomb interaction between the rings in
the absence of tunneling affects the persistent current in each ring and the
ground state configurations. Quantum tunneling between the rings alters
significantly the ground state and the persistent current in the system.
\\ ( http://arxiv.org/abs/0810.5726 , 68kb)
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arXiv:0810.5744
Date: Fri, 31 Oct 2008 17:49:38 GMT (423kb)
Title: Dark state experiments with ultracold, deeply-bound triplet molecules
Authors: Florian Lang, Christoph Strauss, Klaus Winkler, Tetsu Takekoshi,
Rudolf Grimm, Johannes Hecker Denschlag
Categories: cond-mat.other
Comments: 20 pages, 9 figures
\\
We examine dark quantum superposition states of weakly bound Rb2 Feshbach
molecules and tightly bound triplet Rb2 molecules in the rovibrational ground
state, created by subjecting a pure sample of Feshbach molecules in an optical
lattice to a bichromatic Raman laser field. We analyze both experimentally and
theoretically the creation and dynamics of these dark states. Coherent
wavepacket oscillations of deeply bound molecules in lattice sites, as observed
in one of our previous experiments, are suppressed due to laser-induced phase
locking of molecular levels. This can be understood as the appearance of a
novel multilevel dark state. In addition, the experimental methods developed
help to determine important properties of our coupled atom / laser system.
\\ ( http://arxiv.org/abs/0810.5744 , 423kb)
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arXiv:0810.5703
Date: Fri, 31 Oct 2008 15:02:29 GMT (522kb)
Title: Stimulating the production of deeply bound RbCs molecules with laser
pulses: the role of spin-orbit coupling in forming ultracold molecules
Authors: Subhas Ghosal, Richard J. Doyle, Christiane P. Koch and Jeremy M.
Hutson
Categories: physics.atom-ph physics.chem-ph
\\
We investigate the possibility of forming deeply bound ultracold RbCs
molecules by a two-color photoassociation experiment. We compare the results
with those for Rb_2 in order to understand the characteristic differences
between heteronuclear and homonuclear molecules. The major differences arise
from the different long-range potential for excited states. Ultracold 85Rb and
133Cs atoms colliding on the X^1Sigma+ potential curve are initially
photoassociated to form excited RbCs molecules in the region below the Rb(5S) +
Cs(6P_1/2) asymptote. We explore the nature of the Omega=0^+ levels in this
region, which have mixed A^1Sigma^+ and b^3Pi character. We then study the
quantum dynamics of RbCs by a time-dependent wavepacket (TDWP) approach. A
wavepacket is formed by exciting a few vibronic levels and is allowed to
propagate on the coupled electronic potential energy curves. For a detuning of
7.5 cm-1, the wavepacket for RbCs reaches the short-range region in about 13
ps, which is significantly faster than for the homonuclear Rb_2 system; this is
mostly because of the absence of an R^-3 long-range tail in the excited-state
potential curves for heteronuclear systems. We give a simple semiclassical
formula that relates the time taken to the long-range potential parameters. For
RbCs, in contrast to Rb_2, the excited-state wavepacket shows a substantial
peak in singlet density near the inner turning point, and this produces a
significant probability of deexcitation to form ground-state molecules bound by
up to 1500 cm-1. Our analysis of the role of spin-orbit coupling concerns the
character of the mixed states in general and is important for both
photoassociation and stimulated Raman deexcitation.
\\ ( http://arxiv.org/abs/0810.5703 , 522kb)
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arXiv:0810.5738
Date: Fri, 31 Oct 2008 17:26:55 GMT (139kb)
Title: Two-photon coherent control of femtosecond photoassociation
Authors: Christiane P. Koch, Mamadou Ndong, Ronnie Kosloff
Categories: physics.atom-ph physics.chem-ph
\\
Photoassociation with short laser pulses has been proposed as a technique to
create ultracold ground state molecules. A broad-band excitation seems the
natural choice to drive the series of excitation and deexcitation steps
required to form a molecule in its vibronic ground state from two scattering
atoms. First attempts at femtosecond photoassociation were, however, hampered
by the requirement to eliminate the atomic excitation leading to trap
depletion. On the other hand, molecular levels very close to the atomic
transition are to be excited. The broad bandwidth of a femtosecond laser then
appears to be rather an obstacle. To overcome the ostensible conflict of
driving a narrow transition by a broad-band laser, we suggest a two-photon
photoassociation scheme. In the weak-field regime, a spectral phase pattern can
be employed to eliminate the atomic line. When the excitation is carried out by
more than one photon, different pathways in the field can be interfered
constructively or destructively. In the strong-field regime, a temporal phase
can be applied to control dynamic Stark shifts. The atomic transition is
suppressed by choosing a phase which keeps the levels out of resonance. We
derive analytical solutions for atomic two-photon dark states in both the
weak-field and strong-field regime. Two-photon excitation may thus pave the way
toward coherent control of photoassociation. Ultimately, the success of such a
scheme will depend on the details of the excited electronic states and
transition dipole moments. We explore the possibility of two-photon femtosecond
photoassociation for alkali and alkaline-earth metal dimers and present a
detailed study for the example of calcium.
\\ ( http://arxiv.org/abs/0810.5738 , 139kb)
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arXiv:0810.5745
Date: Fri, 31 Oct 2008 18:10:22 GMT (7kb)
Title: Observation of the Nuclear Magnetic Octupole Moment of 87Rb from
Spectroscopic Measurements of Hyperfine Intervals
Authors: Vladislav Gerginov, Carol E. Tanner and W. R. Johnson
Categories: physics.atom-ph
\\
The magnetic octupole moment of 87Rb is determined from hyperfine intervals
in the 5p 2P[3/2] state measured by Ye et al. [Opt. Lett. 21, 1280 (1996)].
Hyperfine constants A = 84.7189(22) MHz, B = 12.4942(43) MHz, and C = -0.12(09)
kHz are obtained from the published measurements. The existence of a
significant value for C indicates the presence of a nuclear magnetic octupole
moment Omega. Combining the hyperfine constants with atomic structure
calculations, we obtain Omega = -0.58(39) (b muN). Second-order corrections
arising from interaction with the nearby 5p 2P[1/2] state are found to be
insignificant.
\\ ( http://arxiv.org/abs/0810.5745 , 7kb)
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arXiv:0811.0314
Date: Mon, 3 Nov 2008 14:59:43 GMT (158kb)
Title: Predicting scattering properties of ultracold atoms: adiabatic
accumulated phase method and mass scaling
Authors: B.J. Verhaar, E.G.M. van Kempen, S.J.J.M.F. Kokkelmans
Categories: cond-mat.other
Comments: 14 pages, 9 figures
\\
Ultracold atoms are increasingly used for high precision experiments that can
be utilized to extract accurate scattering properties. This calls for a
stronger need to improve on the accuracy of interatomic potentials, and in
particular the usually rather inaccurate inner-range potentials. A boundary
condition for this inner range can be conveniently given via the accumulated
phase method. However, in this approach one should satisfy two conditions,
which are in principle conflicting, and the validity of these approximations
comes under stress when higher precision is required. We show that a better
compromise between the two is possible by allowing for an adiabatic change of
the hyperfine mixing of singlet and triplet states for interatomic distances
smaller than the separation radius. A mass scaling approach to relate
accumulated phase parameters in a combined analysis of isotopically related
atom pairs is described in detail and its accuracy is estimated, taking into
account both Born-Oppenheimer and WKB breakdown. We demonstrate how numbers of
singlet and triplet bound states follow from the mass scaling.
\\ ( http://arxiv.org/abs/0811.0314 , 158kb)
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arXiv:0811.0045
Date: Fri, 31 Oct 2008 23:44:53 GMT (1171kb)
Title: Cavity QED characterization of many-body atomic states in double-well
potentials -- The role of dissipation
Authors: W. Chen and P. Meystre
Categories: quant-ph
Comments: 8 pages, 15 figures
\\
When an incident light beam is scattered off a sample of ultracold atoms
trapped in an optical lattice, the statistical properties of the
retro-reflected field contain information about the quantum state of the atoms,
and permit for example to distinguish between atoms in a superfluid and a Mott
insulator state. This paper extends our previous analysis of this problem to
include the effects of cavity damping. We use a Monte Carlo wave function
method to determine the two-time correlation function and time-dependent
physical spectrum of the retro-reflected field in the case of a simple two-well
lattice. We also analyze quantitatively the entanglement between the atoms and
the light field for atoms in a Mott insulator and a superfluid state.
\\ ( http://arxiv.org/abs/0811.0045 , 1171kb)
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arXiv:0811.0264
Date: Mon, 3 Nov 2008 11:17:13 GMT (2059kb)
Title: Two-photon gateway in one-atom cavity quantum electrodynamics
Authors: A. Kubanek, A. Ourjoumtsev, I. Schuster, M. Koch, P.W.H. Pinkse, K.
Murr, G. Rempe
Categories: quant-ph
Comments: PRL, 4 figures
\\
Single atoms absorb and emit light from a resonant laser beam photon by
photon. We show that a single atom strongly coupled to an optical cavity can
absorb and emit resonant photons in pairs. The effect is observed in a photon
correlation experiment on the light transmitted through the cavity. We find
that the atom-cavity system transforms a random stream of input photons into a
correlated stream of output photons, thereby acting as a two-photon gateway.
The phenomenon has its origin in the quantum anharmonicity of the energy
structure of the atom-cavity system. Future applications could include the
controlled interaction of two photons by means of one atom.
\\ ( http://arxiv.org/abs/0811.0264 , 2059kb)
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arXiv:0811.0397
Date: Mon, 3 Nov 2008 21:09:28 GMT (538kb)
Title: Ground State Phase Diagram of the Two-Component Bose-Hubbard Model
Authors: \c{S}.G. S\"oyler, B. Capogrosso-Sansone, N.V. Prokof'ev, B.V.
Svistunov
Categories: cond-mat.other cond-mat.stat-mech
Comments: 4 pages, 3 figures
\\
We have performed path integral Monte Carlo simulations of the two-component
hard-core Bose-Hubbard model on a square lattice at half-integer filling factor
for each component. This system can be realized experimentally with
heteronuclear bosonic mixtures in optical lattices with tunable interspecies
interactions. Our results disagree with preexisting analytical treatments both
quantitatively and qualitatively. We reveal the existence of an additional
solid+superfluid phase for strong anisotropy between the hopping amplitudes
which radically changes the topology of the ground-state phase diagram. The new
phase is a direct consequence of effective interactions between "heavy" atoms
mediated by the "light" superfluid component. Remarkably, mediated interactions
are sign-alternating and thus lead to a rich variety of yet to be discovered
quantum phases.
\\ ( http://arxiv.org/abs/0811.0397 , 538kb)
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arXiv:0811.0555
Date: Tue, 4 Nov 2008 17:05:51 GMT (61kb)
Title: Three-Component Fermi Gas in a one-dimensional Optical Lattice
Authors: P. Azaria, S. Capponi, P. Lecheminant
Categories: cond-mat.str-el
Comments: 4 pages, 3 figures
\\
We investigate the effect of the anisotropy between the s-wave scattering
lengths of a three-component atomic Fermi gas loaded into a one-dimensional
optical lattice. We find four different phases which support trionic
instabilities made of bound states of three fermions. These phases distinguish
themselves by the relative phases between the 2$k_F$ atomic density waves
fluctuations of the three species. At small enough densities or strong
anisotropies we give further evidences for a decoupling and the stabilization
of more conventional BCS phases. Finally our results are discussed in light of
a recent experiment on $^{6}$Li atoms.
\\ ( http://arxiv.org/abs/0811.0555 , 61kb)
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arXiv:0811.0410
Date: Tue, 4 Nov 2008 01:04:07 GMT (2573kb)
Title: The influence of optical molasses in loading a shallow optical trap
Authors: Mathew S. Hamilton, Anthony R. Gorges and Jacob L. Roberts
Categories: physics.atom-ph
Comments: 7 pages, 5 figures
\\
We have examined loading of 85Rb atoms into a shallow Far-Off-Resonance Trap
(FORT) from an optical molasses and compared it to loading from a
Magneto-Optical Trap (MOT). We found that substantially more atoms could be
loaded into the FORT via an optical molasses as compared to loading from the
MOT alone. To determine why this was the case, we measured the rate of atoms
loaded into the FORT and the losses from the FORT during the loading process.
For both MOT and molasses loading, we examined atom load rate and losses over a
range of detunings as well as hyperfine pump powers. We found that the losses
induced during MOT loading were essentially the same as the losses induced
during molasses loading at the same MOT/molasses detuning. In contrast, load
rate of the molasses was higher than that of a MOT at a given detuning. This
caused the optical molasses to be able to load more atoms than the MOT.
Optimization of FORT loading form an optical molasses improved the number of
atoms we could trap by a factor of two over that of optimal loading from a MOT.
\\ ( http://arxiv.org/abs/0811.0410 , 2573kb)
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arXiv:0811.0624
Date: Wed, 5 Nov 2008 11:49:18 GMT (32kb)
Title: Spectral function and quasi-particle damping of interacting bosons in
two dimensions
Authors: Andreas Sinner, Nils Hasselmann, and Peter Kopietz
Categories: cond-mat.other
Comments: 4 pages, 3 figures
\\
We employ the functional renormalization group to study dynamical properties
of the two-dimensional Bose gas. Our approach is free of infrared divergences,
which plague the usual diagrammatic approaches, and is consistent with the
exact Nepomnyashchy identity, which states that the anomalous self-energy
vanishes at zero frequency and momentum. We recover the correct infrared
behavior of the propagators and present explicit results for the spectral
line-shape, from which we extract the quasi-particle dispersion and damping.
\\ ( http://arxiv.org/abs/0811.0624 , 32kb)
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arXiv:0811.0671
Date: Wed, 5 Nov 2008 09:02:37 GMT (848kb)
Title: All-Optical Formation of Quantum Degenerate Mixtures
Authors: Takeshi Fukuhara, Seiji Sugawa, Yosuke Takasu, and Yoshiro Takahashi
Categories: cond-mat.other
Comments: 4 pages, 3 figures
\\
We report the realization of quantum degenerate mixed gases of ytterbium (Yb)
isotopes using all-optical methods. We have succeeded in cooling attractively
interacting 176Yb atoms via sympathetic cooling down to below the Bose-Einstein
transition temperature, coexisting with a stable condensate of 174Yb atoms with
a repulsive interaction. We have observed a rapid atom loss in 176Yb atoms
after cooling down below the transition temperature, which indicates the
collapse of a 176Yb condensate. The sympathetic cooling technique has been
applied to cool a 173Yb-174Yb Fermi-Bose mixture to the quantum degenerate
regime.
\\ ( http://arxiv.org/abs/0811.0671 , 848kb)
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arXiv:0811.0770
Date: Wed, 5 Nov 2008 16:35:33 GMT (75kb)
Title: Enhanced paraconductivity-like fluctuations in the radio frequency
spectra of ultracold Fermi atoms
Authors: Pierbiagio Pieri, Andrea Perali, Giancarlo Calvanese Strinati
Categories: cond-mat.other cond-mat.supr-con
Comments: 17 pages, 5 figures
\\
Ultracold Fermi atoms allow the realization of the crossover from
Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose- Einstein
condensation (BEC), by varying with continuity the attraction between fermions
of different species. In this context, radio frequency (RF) spectroscopy
provides a microscopic probe to infer the nature of fermionic pairing. In the
strongly-interacting regime, this pairing affects a wide temperature range
comprising the critical temperature T_c, in analogy to the pseudogap physics
for high-temperature superconductors. By including what are known in
superconductors as "paraconductivity" fluctuations, here we calculate the RF
spectra above T_c for fermions with balanced populations and compare them with
available experimental data, thus revealing that the role of these fluctuations
is considerably enhanced with respect to superconductors. In addition, we
extract from the spectra an energy scale associated with pairing and relate it
to a universal quantity recently introduced for Fermi gases.
\\ ( http://arxiv.org/abs/0811.0770 , 75kb)
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arXiv:0811.0695
Date: Wed, 5 Nov 2008 10:56:21 GMT (505kb,D)
Title: Dark resonances for ground state transfer of molecular quantum gases
Authors: Manfred J. Mark, Johann G. Danzl, Elmar Haller, Mattias Gustavsson,
Nadia Bouloufa, Olivier Dulieu, Houssam Salami, Tom Bergeman, Helmut Ritsch,
Russell Hart and Hanns-Christoph N\"agerl
Categories: quant-ph
Comments: 7 pages, 4 figures
\\
One possible way to produce ultracold, high-phase-space-density quantum gases
of molecules in the rovibronic ground state is given by molecule association
from quantum-degenerate atomic gases on a Feshbach resonance and subsequent
coherent optical multi-photon transfer into the rovibronic ground state. In
ultracold samples of Cs_2 molecules, we observe two-photon dark resonances that
connect the intermediate rovibrational level |v=73,J=2> with the rovibrational
ground state |v=0,J=0> of the singlet $X^1\Sigma_g^+$ ground state potential.
For precise dark resonance spectroscopy we exploit the fact that it is possible
to efficiently populate the level |v=73,J=2> by two-photon transfer from the
dissociation threshold with the stimulated Raman adiabatic passage (STIRAP)
technique. We find that at least one of the two-photon resonances is
sufficiently strong to allow future implementation of coherent STIRAP transfer
of a molecular quantum gas to the rovibrational ground state |v=0,J=0>.
\\ ( http://arxiv.org/abs/0811.0695 , 505kb)
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arXiv:0811.0844
Date: Wed, 5 Nov 2008 23:51:25 GMT (15kb)
Title: On the spin-liquid phase of one dimensional spin-1 bosons
Authors: F.H.L. Essler, G.V. Shlyapnikov and A.M. Tsvelik
Categories: cond-mat.other cond-mat.str-el
Comments: 17 pages
\\
We consider a model of one dimensional spin-1 bosons with repulsive
density-density interactions and antiferromagnetic exchange. We show that the
low energy effective field theory is given by a spin-charge separated theory of
a Tomonaga-Luttinger Hamiltonian and the O(3) nonlinear sigma model describing
collective charge and spin excitations respectively. At a particular ratio of
the density-density to spin-spin interaction the model is integrable, and we
use the exact solutions to provide an independent derivation of the low energy
effective theory. The system is in a superfluid phase made of singlet pairs of
bosons, and we calculate the long-distance asymptotics of certain correlation
functions.
\\ ( http://arxiv.org/abs/0811.0844 , 15kb)
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arXiv:0811.0874
Date: Thu, 6 Nov 2008 06:12:25 GMT (778kb)
Title: Solitons and vortices in an evolving Bose-Einstein condensate
Authors: Shi-Jie Yang, Quan-Sheng Wu, Shiping Feng, Yu-Chuan Wen, and Yue Yu
Categories: cond-mat.supr-con
Comments: 4 pages, 4 figures
Journal-ref: Physical Review A 77,035602(2008)
\\
Spatiotemporal evolution of a confined Bose-Einstein condensate is studied by
numerically integrating the time-dependent Gross-Pitaevskii equation.
Self-interference between the successively expanding and reflecting nonlinear
matter waves results in spiral atomic density profile, which subsequently
degenerates into an embedding structure: The inner part preserves memory of the
initial states while the outer part forms a sequence of necklacelike rings. The
phase plot reveals a series of discrete concentric belts. The large gradients
between adjacent belts indicate that the ring density notches are dark
solitons. In the dynamical process, a scenario of vortex-antivortex pairs are
spontaneously created and annihilated, whereas the total vorticity keeps
invariant.
\\ ( http://arxiv.org/abs/0811.0874 , 778kb)
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arXiv:0811.1021
Date: Thu, 6 Nov 2008 20:00:31 GMT (14kb)
Title: Bose condensation of interacting gases in traps with and without optical
lattice
Authors: S. Chatterjee, A. E. Meyerovich
Categories: cond-mat.other
Comments: 9 pages, 4 figures
\\
We discuss effects of particle interaction on Bose condensation in
inhomogeneous traps with and without optical lattice. Interaction pushes normal
particles away from the condensate droplet, which is located in the center of
the trap, towards the periphery of the trap where the trapping potential is
large. In the end, the remaining normal particles are squeezed to a quasi-2D
shell around the condensate droplet thus changing the effective dimensionality
of the system. In the absence of the optical lattice the index in the
temperature dependence of the condensate density at the later stages of the
process is close to 2 with a weak dependence on the number of trapped
particles. In the presence of the lattice inside the trap this index acquires a
strong dependence on the number of particles inside the trap and gradually
falls from a 3D to a 2D value with an increase in the number of particles. This
change in index is explained by the lattice-driven spread of the condensate
droplet and the localization of the narrow band particles by the trap
potential.
\\ ( http://arxiv.org/abs/0811.1021 , 14kb)
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arXiv:0811.0925
Date: Thu, 6 Nov 2008 12:02:44 GMT (10kb)
Title: Quantum measuring processes for trapped ultracold bosonic gases
Authors: S. Anderloni, F. Benatti, R. Floreanini, A. Trombettoni
Categories: quant-ph
Comments: 11 pages, LaTeX
\\
The standard experimental techniques usually adopted in the study of the
behaviour of ultracold atoms in optical lattices involve extracting the atom
density profile from absorption images of the atomic sample after trap release.
Quantum mechanically this procedure is described by a generalized measure
(POVM); interference patterns found in absorption images suggest a generalized
measure based on fixed-phase, coherent-like states. We show that this leads to
an average atomic density which differs from the usually adopted one, obtained
as the expectation value of the atom density operator in the many-body state.
\\ ( http://arxiv.org/abs/0811.0925 , 10kb)
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and just for interest's sake:
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arXiv:0811.0237
Date: Mon, 3 Nov 2008 08:11:32 GMT (51kb)
Title: Testing bibliometric indicators by their prediction of scientists
promotions
Authors: Pablo Jensen (LET, Phys-ENS, IXXI), Jean-Baptiste Rouquier (IXXI,
LIP), Yves Croissant (LET)
Categories: physics.soc-ph physics.data-an
Journal-ref: Scientometrics 3, 78 (2008) 0
DOI: 10.1007/s11192-007-2014-3
\\
We have developed a method to obtain robust quantitative bibliometric
indicators for several thousand scientists. This allows us to study the
dependence of bibliometric indicators (such as number of publications, number
of citations, Hirsch index...) on the age, position, etc. of CNRS scientists.
Our data suggests that the normalized h index (h divided by the career length)
is not constant for scientists with the same productivity but differents ages.
We also compare the predictions of several bibliometric indicators on the
promotions of about 600 CNRS researchers. Contrary to previous publications,
our study encompasses most disciplines, and shows that no single indicator is
the best predictor for all disciplines. Overall, however, the Hirsch index h
provides the least bad correlations, followed by the number of papers
published. It is important to realize however that even h is able to recover
only half of the actual promotions. The number of citations or the mean number
of citations per paper are definitely not good predictors of promotion.
\\ ( http://arxiv.org/abs/0811.0237 , 51kb)
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The replacments:
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arXiv:0801.2637
replaced with revised version Fri, 31 Oct 2008 19:28:19 GMT (40kb)
Title: Polarized polariton condensates and coupled XY models
Authors: Jonathan Keeling
Categories: cond-mat.mes-hall
Comments: 6 pages, 3 figures. Extended version
\\ ( http://arxiv.org/abs/0801.2637 , 40kb)
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arXiv:0809.3680
replaced with revised version Fri, 31 Oct 2008 11:05:05 GMT (19kb)
Title: Many-body approach to low-lying collective excitations in a BEC
approaching collapse
Authors: Anindya Biswas and Tapan Kumar Das
Categories: cond-mat.other
Comments: 8 pages, 2 figures
\\ ( http://arxiv.org/abs/0809.3680 , 19kb)
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arXiv:0807.4245
replaced with revised version Mon, 3 Nov 2008 14:39:42 GMT (78kb)
Title: Dirac-point engineering and topological phase transitions in honeycomb
optical lattices
Authors: B. Wunsch, F. Guinea, F. Sols
Categories: cond-mat.mes-hall
Comments: Published version 10 pages, 5 figures
Journal-ref: New J. Phys. 10 (2008) 103027
DOI: 10.1088/1367-2630/10/10/103027
\\ ( http://arxiv.org/abs/0807.4245 , 78kb)
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arXiv:0811.0045
replaced with revised version Tue, 4 Nov 2008 18:15:05 GMT (1171kb)
Title: Cavity QED characterization of many-body atomic states in double-well
potentials -- The role of dissipation
Authors: W. Chen and P. Meystre
Categories: quant-ph
Comments: 8 pages, 15 figures
\\ ( http://arxiv.org/abs/0811.0045 , 1171kb)
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arXiv:0803.2265
replaced with revised version Thu, 6 Nov 2008 10:59:10 GMT (974kb)
Title: Macroscopic Superpositions of Phase States with Bose-Einstein
Condensates
Authors: F. Piazza, L. Pezze', and A. Smerzi
Categories: cond-mat.other
Journal-ref: Phys. Rev. A 78, 051601 (2008)
DOI: 10.1103/PhysRevA.78.051601
\\ ( http://arxiv.org/abs/0803.2265 , 974kb)
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arXiv:0809.1814
replaced with revised version Thu, 6 Nov 2008 17:41:21 GMT (244kb)
Title: Collective oscillations of a Fermi gas in the unitarity limit:
Temperature effects and the role of pair correlations
Authors: S. Riedl, E. R. Sanchez Guajardo, C. Kohstall, A. Altmeyer, M. J.
Wright, J. Hecker Denschlag, R. Grimm, G. M. Bruun, H. Smith
Categories: cond-mat.other
Comments: 8 pages, 5 figures
Journal-ref: Phys. Rev. A 78, 053609 (2008)
DOI: 10.1103/PhysRevA.78.053609
\\ ( http://arxiv.org/abs/0809.1814 , 244kb)
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arXiv:0709.0613
replaced with revised version Thu, 6 Nov 2008 14:36:58 GMT (334kb)
Title: Complementarity and uncertainty relations for matter wave interferometry
Authors: K.-P. Marzlin, B. C. Sanders, and P. L. Knight
Categories: quant-ph
Comments: nine pages, five figures
\\ ( http://arxiv.org/abs/0709.0613 , 334kb)
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Till next time,
Matt.
-- ========================================================================= 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/ ========================================================================= Matt's arXiv selection: weekly summary of cold-atom papers from arXiv.org http://www.physics.uq.edu.au/people/mdavis/matts_arXiv/ ========================================================================= Legal stuff: Unless stated otherwise, this e-mail represents only the views of the sender and not the views of the University of Queensland =========================================================================Received on Mon Nov 10 2008 - 13:55:19 EST
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