From: Matthew Davis <mdavis_at_physics.uq.edu.au>

Date: Thu, 19 Jun 2008 22:40:30 +1000

Date: Thu, 19 Jun 2008 22:40:30 +1000

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

Still lagging behind... this week there were 26 new preprints and 8 replacements.

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arXiv:0805.3519

Date: Thu, 22 May 2008 18:03:04 GMT (411kb)

Title: Observation of a 2D Bose-gas: from thermal to quasi-condensate to

superfluid

Authors: P. Clad\'e, C. Ryu, A. Ramanathan, K. Helmerson and W. D. Phillips

Categories: cond-mat.other

Comments: 5 pages, 6 figures

\\

We present experimental results on a Bose gas in a quasi-2D geometry near the

Berezinskii, Kosterlitz and Thouless (BKT) transition temperature. By measuring

the density profile, \textit{in situ} and after time of flight, and the

coherence length, we identify different states of the gas. In particular, we

observe that the gas develops a bimodal distribution without long range order.

In this state, the gas presents a longer coherence length than the thermal

cloud; it is quasi-condensed but is not superfluid. Experimental evidence

indicates that we observe the superfluid transition (BKT transition).

\\ ( http://arxiv.org/abs/0805.3519 , 411kb)

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arXiv:0805.3663

Date: Fri, 23 May 2008 19:57:53 GMT (481kb)

Title: Phase diagram, extended domain walls, and soft collective modes in a

three component fermionic superfluid

Authors: G. Catelani, E. A. Yuzbashyan

Categories: cond-mat.other cond-mat.supr-con

Comments: 16 pages, 6 figures

\\

We study the phase diagram of a three component Fermi gas with weak

attractive interactions, which shows three superfluid and one normal phases. At

weak symmetry breaking between the components the existence of domain walls

interpolating between two superfluids introduces a new length scale much larger

than the coherence length of each superfluid. This, in particular, limits the

applicability of the local density approximation in the trapped case, which we

also discuss. In the same regime the system hosts soft collective modes with a

mass much smaller than the energy gaps of individual superfluids. We derive

their dispersion relations at zero and finite temperatures and demonstrate that

their presence leads to a significant enhancement of fluctuations near the

superfluid-normal transitions.

\\ ( http://arxiv.org/abs/0805.3663 , 481kb)

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arXiv:0805.3667

Date: Fri, 23 May 2008 17:17:37 GMT (30kb)

Title: Spin polarons and molecules in strongly-interacting atomic Fermi gases

Authors: P. Massignan, G. M. Bruun, H. T. C. Stoof

Categories: cond-mat.other

Comments: 4 pages, 5 figures

\\

We examine pairing and molecule formation in strongly-interacting Fermi

gases, and we discuss how radio-frequency (RF) spectroscopy can reveal these

features. For the balanced case, the emergence of stable molecules in the BEC

regime results in a two-peak structure in the RF spectrum with clearly visible

medium effects on the low-energy part of the molecular wavefunction. For the

highly-imbalanced case, we show the existence of a well-defined quasiparticle

(a spin polaron) on both sides of the Feshbach resonance, we evaluate its

lifetime, and we illustrate how its energy may be measured by RF spectroscopy.

\\ ( http://arxiv.org/abs/0805.3667 , 30kb)

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arXiv:0805.3680

Date: Fri, 23 May 2008 18:32:18 GMT (754kb)

Title: Quantum behavior of the dc SQUID phase qubit

Authors: Kaushik Mitra, F. W. Strauch, C. J. Lobb, J. R. Anderson, F. C.

Wellstood, and Eite Tiesinga

Categories: cond-mat.supr-con cond-mat.other

Comments: 38 pages, 7 figures

\\

We analyze the behavior of a dc Superconducting Quantum Interference Device

(SQUID) phase qubit in which one junction acts as a phase qubit and the rest of

the device provides isolation from dissipation and noise in the bias leads.

Ignoring dissipation, we find the two-dimensional Hamiltonian of the system and

use numerical methods and a cubic approximation to solve Schrodinger's equation

for the eigenstates, energy levels, tunneling rates, and expectation value of

the currents in the junctions. Using these results, we investigate how well

this design provides isolation while preserving the characteristics of a phase

qubit. In addition, we show that the expectation value of current flowing

through the isolation junction depends on the state of the qubit and can be

used for non-destructive read out of the qubit state.

\\ ( http://arxiv.org/abs/0805.3680 , 754kb)

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arXiv:0805.3693

Date: Sun, 25 May 2008 01:47:34 GMT (204kb)

Title: Itinerant Ferromagnetism in an Atom Trap

Authors: Ilya Berdnikov, P. Coleman, Steven H. Simon

Categories: cond-mat.str-el

\\

We propose an experiment to explore the magnetic phase transitions in

interacting fermionic Hubbard systems, and establish signatures of

ferromagnetic correlations in the observed ground states. We find that for

large trap radii (trap radius $R_T > 4$, in units of coherence length $\xi$),

ground states are topological in nature -- a ``skyrmion'' in 2D, and a

``hedgehog'' in 3D. Finally, we describe how to obtain the ferromagnetic phase

diagram of itinerant electron systems from these experiments.

\\ ( http://arxiv.org/abs/0805.3693 , 204kb)

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arXiv:0805.3713

Date: Fri, 23 May 2008 20:36:46 GMT (17kb)

Title: Local stress and superfluid properties of solid Helium-4

Authors: L. Pollet, M. Boninsegni, A. B. Kuklov, N.V. Prokofev, B.V. Svistunov,

M. Troyer

Categories: cond-mat.stat-mech

\\

More than half a century ago Penrose asked: are the superfluid and solid

state of matter mutually exclusive or do there exist "supersolid" materials

where the atoms form a regular lattice and simultaneously flow without

friction? Recent experiments provide evidence that supersolid behavior indeed

exists in Helium-4 -- the most quantum material known in Nature. In this paper

we show that large local strain in the vicinity of crystalline defects is the

origin of supersolidity in Helium-4. Although ideal crystals of Helium-4 are

not supersolid, the gap for vacancy creation closes when applying a moderate

stress. While a homogeneous system simply becomes unstable at this point, the

stressed core of crystalline defects (dislocations and grain boundaries)

undergoes a radical transformation and can become superfluid.

\\ ( http://arxiv.org/abs/0805.3713 , 17kb)

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arXiv:0805.3730

Date: Fri, 23 May 2008 23:31:58 GMT (132kb)

Title: Nonlinear Dynamic Phenomena in Macroscopic Tunneling

Authors: G. Dekel, O.V. Farberovich, A. Soffer, V. Fleurov

Categories: cond-mat.other

Comments: 14 pages, 6 figures

\\

Numerical simulations of the NLSE (or GPE) are presented demonstrating

emission of short pulses of the matter (light) density formed in the course of

tunneling in wave-guided light and/or trapped BEC. The phenomenon is observed

under various conditions, for nonlinearities of different signs, zero

nonlinearity included. We study, both numerically and analytically, pulsations

of matter (light) remaining within the trap and use the results in order to

induce emission of sequential pulses by properly narrowing the trap. This

allows us to propose a mechanism for a realization of Atom Pulse Laser.

\\ ( http://arxiv.org/abs/0805.3730 , 132kb)

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arXiv:0805.3734

Date: Sat, 24 May 2008 01:00:22 GMT (681kb)

Title: Stochastic time-dependent current-density functional theory: a

functional theory of open quantum systems

Authors: R. D'Agosta and M. Di Ventra

Categories: cond-mat.str-el cond-mat.mes-hall

Comments: 16 pages, 7 figures, RevTex4

\\

The dynamics of a many-body system coupled to an external environment

represents a fundamentally important problem. To this class of open quantum

systems pertains the study of energy transport and dissipation, dephasing,

quantum measurement and quantum information theory, phase transitions driven by

dissipative effects, etc. Here, we discuss in detail an extension of

time-dependent current-density-functional theory (TDCDFT), we named stochastic

TDCDFT [Phys. Rev. Lett. {\bf 98}, 226403 (2007)], that allows the description

of such problems from a microscopic point of view. We discuss the assumptions

of the theory, its relation to a density matrix formalism, and the limitations

of the latter in the present context. In addition, we describe a numerically

convenient way to solve the corresponding equations of motion, and apply this

theory to the dynamics of a 1D gas of excited bosons confined in a harmonic

potential and in contact with an external bath.

\\ ( http://arxiv.org/abs/0805.3734 , 681kb)

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arXiv:0805.3786

Date: Sun, 25 May 2008 09:52:09 GMT (101kb)

Title: Fermionization and bosonization of expanding 1D anyonic fluids

Authors: A. del Campo

Categories: cond-mat.stat-mech

Comments: 5 figures, 4 pages

\\

The momentum distribution of an expanding cloud of one-dimensional hard-core

anyons is studied by an exact numerical approach, and shown to become

indistinguishable from that of a non-interacting spin-polarized Fermi gas for

large enough times (dynamical fermionization). We also consider the expansion

of one-dimensional anyons with strongly attractive short-range interactions

suddenly released from a parabolic external potential, and find that momentum

distribution approaches that of its dual system, the ideal Bose gas (dynamical

bosonization). For both processes the characteristic time scales are

identified, and the effect of the initial confinement is analyzed comparing the

dynamics associated with both harmonic and hard-wall traps.

\\ ( http://arxiv.org/abs/0805.3786 , 101kb)

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arXiv:0805.3870

Date: Mon, 26 May 2008 03:59:40 GMT (379kb)

Title: Stability of the density-wave state of a dipolar condensate in a pancake

trap

Authors: O. Dutta, R. Kanamoto, P. Meystre

Categories: cond-mat.other

\\

We study a dipolar boson-fermion mixture in a pancake geometry at absolute

zero temperature, generalizing our previous work on the stability of polar

condensates and the formation of a density-wave state in cylindrical traps.

After examining the dependence of the polar condensate stability on the

strength of the fermion-induced interaction, we determine the transition point

from a ground-state Gaussian to a hexagonal density-wave state. We use a

variational principle to analyze the stability properties of those density-wave

state.

\\ ( http://arxiv.org/abs/0805.3870 , 379kb)

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arXiv:0805.3889

Date: Mon, 26 May 2008 16:43:33 GMT (57kb)

Title: Effect of disorder on the interacting Fermi gases in a one-dimensional

optical lattice

Authors: Gao Xianlong, M. Polini, M. P. Tosi, and B. Tanatar

Categories: cond-mat.dis-nn cond-mat.str-el

Comments: 11 pages, 6 figures, submitted

\\

Interacting two-component Fermi gases loaded in a one-dimensional (1D)

lattice and subjected to an harmonic trapping potential exhibit interesting

compound phases in which fluid regions coexist with local Mott-insulator and/or

band-insulator regions. Motivated by experiments on cold atoms inside

disordered optical lattices, we present a theoretical study of the effects of a

correlated random potential on these ground-state phases. We employ a lattice

version of density-functional theory within the local-density approximation to

determine the density distribution of fermions in these phases. The

exchange-correlation potential is obtained from the Lieb-Wu exact solution of

Fermi-Hubbard model. On-site disorder (with and without Gaussian correlations)

and harmonic trap are treated as external potentials. We find that disorder has

two main effects: (i) it destroys the local insulating regions if it is

sufficiently strong compared with the on-site atom-atom repulsion, and (ii) it

induces an anomaly in the inverse compressibility at low density from quenching

of percolation. For sufficiently large disorder correlation length the

enhancement in the inverse compressibility diminishes.

\\ ( http://arxiv.org/abs/0805.3889 , 57kb)

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arXiv:0805.3735

Date: Sat, 24 May 2008 01:08:16 GMT (163kb)

Title: Coupling nanomechanical cantilevers to dipolar molecules

Authors: S. Singh, M. Bhattacharya, O. Dutta and P. Meystre

Categories: quant-ph

Comments: 3 figures, 4pages

\\

We investigate the coupling of a nanomechanical oscillator in the quantum

regime with molecular (electric) dipoles. We find theoretically that the

cantilever can produce single-mode squeezing of the center-of-mass motion of an

isolated trapped molecule and two-mode squeezing of the phonons of an array of

molecules. This work opens up the possibility of manipulating dipolar crystals,

which have been recently proposed as quantum memory, and more generally, is

indicative of the promise of nanoscale cantilevers for the quantum detection

and control of atomic and molecular systems.

\\ ( http://arxiv.org/abs/0805.3735 , 163kb)

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arXiv:0805.3797

Date: Sat, 24 May 2008 23:09:20 GMT (500kb,D)

Title: Faraday spectroscopy of atoms confined in a dark optical trap

Authors: Matthew L. Terraciano, Mark Bashkansky, Fredrik Fatemi

Categories: quant-ph

Comments: 6 pages, 8 figures Accepted in Phys. Rev. A

\\

We demonstrate Faraday spectroscopy with high duty cycle and sampling rate

using atoms confined to a blue-detuned optical trap. Our trap consists of a

crossed pair of high-charge-number hollow laser beams, which forms a dark,

box-like potential. We have used this to measure transient magnetic fields in a

500-micron-diameter spot over a 400 ms time window with nearly unit duty cycle

at a 500 Hz sampling rate. We use these measurements to quantify and compensate

time-varying magnetic fields to ~10 nT per time sample.

\\ ( http://arxiv.org/abs/0805.3797 , 500kb)

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arXiv:0805.3801

Date: Sat, 24 May 2008 23:46:47 GMT (42kb)

Title: Photo-detection using Bose-condensed atoms in a micro trap

Authors: S. Wallentowitz, A. B. Klimov

Categories: quant-ph

Comments: 11 pages, 5 figures

\\

A model of photo-detection using a Bose--Einstein condensate in an atom-chip

based micro trap is analyzed. Atoms absorb photons from the incident light

field, receive part of the photon momentum and leave the trap potential. Upon

counting of escaped atoms within predetermined time intervals, the photon

statistics of the incident light is mapped onto the atom-count statistics.

Whereas traditional photo-detection theory treats the emission centers of photo

electrons as distinguishable, here the centers of escaping atoms are condensed

and thus indistinguishable atoms. From this a deviation of the commonly known

counting formula is derived.

\\ ( http://arxiv.org/abs/0805.3801 , 42kb)

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arXiv:0805.3854

Date: Mon, 26 May 2008 00:54:53 GMT (206kb)

Title: Single Atom Detection With Optical Cavities

Authors: R. Poldy, B. C. Buchler, J. C. Close

Categories: quant-ph

Comments: 11 pages, 8 figures, submitted to PRA

\\

We present a thorough analysis of single atom detection using optical

cavities. The large set of parameters that influence the signal-to-noise ratio

for cavity detection is considered, with an emphasis on detunings, probe power,

cavity finesse and photon detection schemes. Real device operating restrictions

for single photon counting modules and standard photodiodes are included in our

discussion, with heterodyne detection emerging as the clearly favourable

technique, particularly for detuned detection at high power.

\\ ( http://arxiv.org/abs/0805.3854 , 206kb)

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arXiv:0805.4002

Date: Mon, 26 May 2008 18:23:05 GMT (198kb)

Title: A Wave Function approach to dissipative processes

Authors: Yvan Castin, Jean Dalibard and Klaus Molmer

Categories: quant-ph

\\

Due to growing interest in quantum measurement, control and feedback, we

reproduce a manuscript from 1992, presenting a simple physical and mathematical

derivation of stochastic differential equations for wave functions of probed

quantum systems. V. P. Belavkins seminal quantum filtering theory with similar

equations, developed in the 1980es, was not known to the authors at the time of

writing of the present manuscript.

\\ ( http://arxiv.org/abs/0805.4002 , 198kb)

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arXiv:0805.3708

Date: Fri, 23 May 2008 20:26:38 GMT (164kb,D)

Title: Light Assisted Collisional Loss in a $^{85/87}$Rb Ultracold Optical Trap

Authors: Anthony R. Gorges, Nicholas S. Bingham, Michael K. DeAngelo, Mathew S.

Hamilton, and Jacob L. Roberts

Categories: physics.atom-ph

Comments: about 8 pages, 5 figures

\\

We have studied hetero- and homonuclear excited state/ground state collisions

by loading both $^{85}$Rb and $^{87}$Rb into a far off resonant trap (FORT).

Because of the relatively weak confinement of the FORT, we expect the hyperfine

structure of the different isotopes to play a crucial role in the collision

rates. This dependence on hyperfine structure allows us to measure collisions

associated with long range interatomic potentials of different structure: such

as long and short ranged; or such as purely attractive, purely repulsive, or

mixed attractive and repulsive. We observe significantly different loss rates

for different excited state potentials. Additionally, we observe that some

collisional channels' loss rates are saturated at our operating intensities

(~15 mW/cm$^{2}$). These losses are important limitations in loading dual

isotope optical traps.

\\ ( http://arxiv.org/abs/0805.3708 , 164kb)

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arXiv:0805.4028

Date: Tue, 27 May 2008 00:59:05 GMT (362kb)

Title: 1D-FFLO state in the absence of time-reversal symmetry breaking

Authors: Trinanjan Datta

Categories: cond-mat.str-el cond-mat.supr-con

Comments: 5 pages, 3 figures

\\

A novel route to a one-dimensional Fulde-Ferrell-Larkin-Ovchinnikov (1D-FFLO)

state in the absence of broken time-reversal symmetry is proposed in this

paper. At present such a state may be encouraged in a clean AlAs quantum wire.

Using the AlAs quantum wire as an example it is shown using bosonization and

the renormalization group approach that the 1D-FFLO state can arise due to a

combination of Coulomb interactions and the unique bandstructure arrangement of

the AlAs quantum wire. The present theoretical proposal is very general and is

applicable to other systems with similar fermionic interaction terms.

\\ ( http://arxiv.org/abs/0805.4028 , 362kb)

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arXiv:0805.4036

Date: Tue, 27 May 2008 02:19:32 GMT (37kb)

Title: Diagrammatic calculation of energy spectrum of quantum impurity in

degenerate Bose-Einstein condensate

Authors: Alexey Novikov, Mikhail Ovchinnikov

Categories: quant-ph

\\

In this paper we considered a quantum particle moving through delute

Bose-Einstein condensate at zero temperature. In our formulation the impurity

particle interacts with the gas of uncoupled Bogoliubov's excitations. We

constructed the perturbation theory for the Green's function of the impurity

particle with respect to the impurity-condensate interaction employing the

coherent-state path integral approach. The perturbative expansion for the

Green's function is resumed into the expansion for its poles with the help of

the diagrammatic technique developed in this work. The dispersion relation for

the impurity clothed by condensate excitations is obtained and effective mass

is evaluated beyond the Golden rule approximation.

\\ ( http://arxiv.org/abs/0805.4036 , 37kb)

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arXiv:0805.4198

Date: Tue, 27 May 2008 20:01:04 GMT (40kb)

Title: Realizing the strongly correlated $d$-Mott state in a fermionic cold

atom optical lattice

Authors: Michael R. Peterson, Chuanwei Zhang, Sumanta Tewari, S. Das Sarma

Categories: cond-mat.str-el

Comments: 4 pages, 5 figures

\\

We show that a new state of matter, the $d$-Mott state, characterized by a

non-zero expectation value of a local plaquette operator embedded in an

insulating state, can be engineered using ultra-cold atomic fermions in

two-dimensional double-well optical lattices. We characterize and analyze the

parameter regime where the $d$-Mott state is stable. We predict the testable

signatures of the state in the time-of-flight measurements.

\\ ( http://arxiv.org/abs/0805.4198 , 40kb)

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arXiv:0805.4203

Date: Tue, 27 May 2008 20:13:51 GMT (128kb)

Title: $p_{x}+ip_{y}$ superfluid from s-wave interactions of fermionic cold

atoms

Authors: Chuanwei Zhang, Sumanta Tewari, Roman Lutchyn, and S. Das Sarma

Categories: cond-mat.mes-hall cond-mat.str-el

Comments: 4 pages, 1 figure

\\

Two-dimensional ($p_{x}+ip_{y}$) superfluids/superconductors offer a

playground for studying intriguing physics such as quantum teleportation,

non-Abelian statistics, and topological quantum computation. Creating such a

superfluid in cold fermionic atom optical traps using p-wave Feshbach resonance

is turning out to be challenging. Here we propose a method to create a

$p_{x}+ip_{y}$ superfluid directly from an s-wave interaction making use of a

topological Berry phase, which can be artificially generated. We discuss ways

to detect the spontaneous Hall mass current, which acts as a diagnostic for the

chiral p-wave superfluid.

\\ ( http://arxiv.org/abs/0805.4203 , 128kb)

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arXiv:0805.4261

Date: Wed, 28 May 2008 05:34:22 GMT (997kb)

Title: Mott Phase in Polarized Two-component Atomic Fermi Lattice Gas:A

Playground for S=1/2 Heisenberg Model in Magnetic Field

Authors: M. Machida, M. Okumura, S. Yamada, T. Deguchi, Y. Ohashi, H. Matsumoto

Categories: cond-mat.str-el

\\

We investigate effects of pseudo-spin population imbalance on Mott phases in

1D trapped two-component atomic Fermi gases loaded on optical lattices based on

the repulsive Hubbard model in harmonic traps. By using the density matrix

renormalization group method, we numerically calculate density profiles of each

component and clarify the pseudo-spin magnetism. In the case of large

population imbalance, we find Wigner crystal like structures for the spatial

distribution of the minority pseudo-spin component inside the central Mott

core. When the population imbalance becomes small, the structure disappears,

and antiferromagnetic configurations instead appear together with their

spin-density wave like modulations. These all features are well described by

S=1/2 antiferromagnetic Heisenberg chain under magnetic field.

\\ ( http://arxiv.org/abs/0805.4261 , 997kb)

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arXiv:0805.4295

Date: Wed, 28 May 2008 11:28:23 GMT (341kb)

Title: Fast Sweeping into Feshbach Molecules as a Probe of Fermionic

Condensates

Authors: S. Matyjaskiewicz, M. H. Szymanska, K. Goral

Categories: cond-mat.other

Comments: 5 pages, 3 figures

\\

Fast sweep projection onto Feshbach molecules has been widely used as a probe

to explore the properties of fermionic condensates, in particular the

condensate fraction. By determining the exact dynamics of a pair of atoms in

time varying magnetic fields across a Feshbach resonance, we calculate the

number of condensed and noncondensed molecules created after fast magnetic

field sweeps from the BCS to the BEC side of the resonance. We analyse the

dependence of the molecular conversion efficiency for condensed and

noncondensed molecules on the sweep rate, and on the initial and final magnetic

fields, for $^{40}$K and $^{6}$Li resonances; and discuss the relation between

the initial fermionic condensate fraction and the molecular condensate fraction

measured after the sweep.

\\ ( http://arxiv.org/abs/0805.4295 , 341kb)

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arXiv:0805.4327

Date: Wed, 28 May 2008 12:07:03 GMT (776kb)

Title: Electromagnetically induced transparency of an interacting cold Rydberg

ensemble

Authors: K. J. Weatherill, J. D. Pritchard, R. P. Abel, M. G. Bason, A. K.

Mohapatra and C. S. Adams

Categories: quant-ph

Comments: 4 pages, 4 figures

\\

We study electromagnetically induced transparency (EIT) of a weakly

interacting cold Rydberg gas. We show that the onset of interactions is

manifest as a depopulation of the Rydberg state and numerically model this

effect by adding a density-dependent non-linear term to the optical Bloch

equations. In the limit of a weak probe where the depopulation effect is

negligible, we observe no evidence of interaction induced decoherence and

obtain a narrow Rydberg dark resonance with a linewidth of <600 kHz, limited by

the Rabi frequency of the coupling beam

\\ ( http://arxiv.org/abs/0805.4327 , 776kb)

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arXiv:0805.4484

Date: Thu, 29 May 2008 08:49:17 GMT (165kb,D)

Title: The p-band in a rotating optical lattice

Authors: R.O. Umucalilar, M.O. Oktel

Categories: cond-mat.other

Comments: 7 pages, 4 figures

\\

We investigate the effects of rotation on the excited bands of a tight

binding lattice, focusing particulary on the first excited (p-) band. Both the

on-site energies and the hopping between lattice sites are modified by the

effective magnetic field created by rotation, causing a non-trivial splitting

and magnetic fine structure of the p-band. We show that Peierls substitution

can be modified to describe p-band under rotation, and use this method to

derive an effective Hamiltonian. We compare the spectrum of the effective

Hamiltonian with a first principles calculation of the magnetic band structure

and find excellent agreement, confirming the validity of our approach. We also

discuss the on-site interaction terms for bosons and argue that many-particle

phenomena in a rotating p-band can be investigated starting from this effective

Hamiltonian.

\\ ( http://arxiv.org/abs/0805.4484 , 165kb)

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arXiv:0805.4447

Date: Wed, 28 May 2008 22:47:05 GMT (3kb)

Title: Stability of Double-Ring Bose-Einstein Condensates

Authors: Joachim Brand, Tania J. Haigh, and Ulrich Z\"ulicke

Categories: quant-ph

Comments: 1 page, comment on Phys. Rev. Lett. 98, 050401 (2007)

[arXiv:quant-ph/0609133v2]

\\

We revisit recent claims about the instability of non-rotating coupled

annular Bose-Einstein condensates (BECs) leading to the emergence of

angular-momentum Josephson oscillation. In their Letter [Phys. Rev. Lett. 98,

050401 (2007), arXiv:quant-ph/0609133v2], Lesanovsky and von Klitzing predict

all stationary states with uniform density to be unstable. This prediction

turns out to be based on faulty calculations leading to incorrect conclusions.

We show that there is a stable non-rotating and uniform ground state for any

value of the tunnel coupling and repulsive interactions. The instability of an

excited state with $\pi$ phase difference between the condensates can be

interpreted in terms of the familiar snake instability.

\\ ( http://arxiv.org/abs/0805.4447 , 3kb)

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The replacements:

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arXiv:0801.2910

replaced with revised version Mon, 26 May 2008 13:35:41 GMT (477kb)

Title: Functional renormalization for Bose-Einstein Condensation

Authors: S. Floerchinger and C. Wetterich

Categories: cond-mat.supr-con cond-mat.str-el hep-th

Comments: 21 pages, 16 figures. Reference added

Journal-ref: Phys. Rev. A 77, 053603 (2008)

DOI: 10.1103/PhysRevA.77.053603

\\ ( http://arxiv.org/abs/0801.2910 , 477kb)

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arXiv:0802.0333

replaced with revised version Mon, 26 May 2008 03:47:30 GMT (205kb)

Title: Magneto-Optical Stern-Gerlach Effect in Atomic Ensemble

Authors: Yu Guo, Lan Zhou, Le-Man Kuang, C.P. Sun

Categories: quant-ph

Comments: 7 pages, 5 figures

\\ ( http://arxiv.org/abs/0802.0333 , 205kb)

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arXiv:0802.1585

replaced with revised version Sat, 24 May 2008 02:00:48 GMT (897kb)

Title: Experimental Realization of an Optical One-Way Barrier for Neutral Atoms

Authors: Jeremy J. Thorn, Elizabeth A. Schoene, Tao Li, and Daniel A. Steck

Categories: physics.atom-ph

Comments: 5 pages, 4 figures; includes changes to address referee comments

\\ ( http://arxiv.org/abs/0802.1585 , 897kb)

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arXiv:0801.2056

replaced with revised version Tue, 27 May 2008 09:12:52 GMT (206kb)

Title: Double and negative reflection of cold atoms in non-Abelian gauge

potentials

Authors: Gediminas Juzeliunas, Julius Ruseckas, Andreas Jacob, Luis Santos,

Patrik Ohberg

Categories: cond-mat.other physics.atom-ph quant-ph

Comments: 5 figures corrected references

Journal-ref: Phys. Rev. Lett. 100, 200405 (2008)

DOI: 10.1103/PhysRevLett.100.200405

\\ ( http://arxiv.org/abs/0801.2056 , 206kb)

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arXiv:0804.0109

replaced with revised version Tue, 27 May 2008 12:41:23 GMT (213kb)

Title: Mechanisms for Lasing with Cold Atoms as the Gain Medium

Authors: William Guerin (INLN), Franck Michaud (INLN), Robin Kaiser (INLN)

Categories: physics.atom-ph cond-mat.dis-nn physics.optics

\\ ( http://arxiv.org/abs/0804.0109 , 213kb)

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arXiv:cond-mat/0702462

replaced with revised version Thu, 29 May 2008 12:20:34 GMT (49kb)

Title: Efimov states near a Feshbach resonance

Authors: P. Massignan and H. T. C. Stoof

Categories: cond-mat.other

Comments: 4 pages, 5 figures; revised discussion after Eq. (2) on the insertion

of a correction to the inverse two-body T-matrix

\\ ( http://arxiv.org/abs/cond-mat/0702462 , 49kb)

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\\

arXiv:0708.1898

replaced with revised version Thu, 29 May 2008 10:47:41 GMT (329kb)

Title: On the dynamics of point vortices in a quantum gas confined in an

annular region

Authors: Markus Lakaniemi

Categories: cond-mat.stat-mech quant-ph

Comments: 14 pages, 4 figures. A new version of the original paper

\\ ( http://arxiv.org/abs/0708.1898 , 329kb)

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\\

arXiv:0803.0183

replaced with revised version Thu, 29 May 2008 16:30:26 GMT (316kb)

Title: Optimal control of atom transport for quantum gates in optical lattices

Authors: G. De Chiara, T. Calarco, M. Anderlini, S. Montangero, P. J. Lee, B.

L. Brown, W. D. Phillips, and J. V. Porto

Categories: quant-ph cond-mat.other

Comments: revised version: minor changes, 2 references added, published version

Journal-ref: Phys. Rev. A 77, 052333 (2008)

DOI: 10.1103/PhysRevA.77.052333

\\ ( http://arxiv.org/abs/0803.0183 , 316kb)

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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 Fri Jul 04 2008 - 08:30:27 EST

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