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

Date: Mon, 29 Oct 2007 22:41:14 +1000 (EST)

Date: Mon, 29 Oct 2007 22:41:14 +1000 (EST)

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

Hello again,

Thankfully the teaching semester is now over and this should give me a chance to

get you back up to date. For this week (which was now three weeks ago!) there

were 25 new preprints and 14 replacements:

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arXiv:0709.4554

Date: Fri, 28 Sep 2007 09:00:07 GMT (28kb)

Title: Feshbach resonances in mixtures of ultracold $^6$Li and $^{87}$Rb gases

Authors: B. Deh, C. Marzok, C. Zimmermann and Ph. W. Courteille

Categories: cond-mat.other cond-mat.soft

\\

We report on the observation of several Feshbach resonances in collisions

between ultracold $^6$Li and $^{87}$Rb atoms in their respective hyperfine

ground states $|F,m_F>=|1/2,1/2>$ and $|1,1>$. The resonances show up as trap

losses for the $^6$Li cloud induced by inelastic Li-Rb-Rb three-body

collisions. The magnetic field values where they occur represent important

benchmarks for an accurate determination of the interspecies interaction

potentials. A broad Feshbach resonance located at 1066.92 G opens interesting

prospects for the creation of ultracold heteronuclear molecules. We furthermore

observe a strong enhancement of the narrow p-wave Feshbach resonance in

collisions of $^6$Li atoms at 158.55 G in the presence of a dense $^{87}$Rb

cloud. The effect of the $^{87}$Rb cloud is to introduce Li-Li-Rb three-body

collisions occurring at a higher rate than Li-Li-Li collisions.

\\ ( http://arxiv.org/abs/0709.4554 , 28kb)

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arXiv:0709.4596

Date: Fri, 28 Sep 2007 12:28:09 GMT (177kb)

Title: Ground state fidelity from tensor network representations

Authors: Huan-Qiang Zhou, Roman Orus and Guifre Vidal

Categories: cond-mat.stat-mech cond-mat.str-el

Comments: 5 pages, 2 figures

\\

For any $D$-dimensional quantum lattice system, the fidelity between two

ground state many-body wave functions is mapped onto the partition function of

a $D$-dimensional classical statistical vertex lattice model with the same

lattice geometry. The fidelity per lattice site, analogous to the free energy

per site, is well-defined in the thermodynamic limit and can be used to

characterize the phase diagram of the model. We explain how to compute the

fidelity per site in the context of tensor network algorithms, and demonstrate

the approach by analyzing the two-dimensional quantum Ising model with

transverse and parallel magnetic fields.

\\ ( http://arxiv.org/abs/0709.4596 , 177kb)

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arXiv:0709.4609

Date: Fri, 28 Sep 2007 13:20:37 GMT (38kb)

Title: Super-Tonks-Girardeau regime in trapped one-dimensional dipolar gases

Authors: G. E. Astrakharchik and Yu. E. Lozovik

Categories: cond-mat.other

\\

Possible signatures of a super-Tonks-Girardeau gas in bosonic systems of

trapped quasi-one-dimensional dipoles are discussed at zero temperature. We

provide estimation of the frequency of the lowest compressional mode and

compare it to analytical results derived using harmonic approach in the high

density regime. We construct an exact mapping of the ground-state wave function

of one-dimensional dipolar system of bosons, fermions and Bose-Fermi mixture

and conclude that local properties and energy are the same at zero temperature.

A question of to which extent the dipolar potential can be treated long- or

short- range is discussed.

\\ ( http://arxiv.org/abs/0709.4609 , 38kb)

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arXiv:0709.4620

Date: Fri, 28 Sep 2007 14:28:38 GMT (244kb)

Title: Mott transition in one dimension: Benchmarking dynamical cluster

approaches

Authors: Matthias Balzer, Werner Hanke and Michael Potthoff

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

Comments: 19 pages, 19 figures

\\

The variational cluster approach (VCA) is applied to the one-dimensional

Hubbard model at zero temperature using clusters (chains) of up to ten sites

with full diagonalization and the Lanczos method as cluster solver. Within the

framework of the self-energy-functional theory (SFT), different cluster

reference systems with and without bath degrees of freedom, in different

topologies and with different sets of variational parameters are considered.

Static and one-particle dynamical quantities are calculated for half-filling as

a function of U as well as for fixed U as a function of the chemical potential

to study the interaction- and filling-dependent metal-insulator (Mott)

transition. The recently developed Q-matrix technique is used to compute the

SFT grand potential. For benchmarking purposes we compare the VCA results with

exact results available from the Bethe ansatz, with essentially exact dynamical

DMRG data, with (cellular) dynamical mean-field theory and full diagonalization

of isolated Hubbard chains. Several issues are discussed including convergence

of the results with cluster size, the ability of cluster approaches to access

the critical regime of the Mott transition, efficiency in the optimization of

correlated-site vs. bath-site parameters and of multi-dimensional parameter

optimization. We also study the role of bath sites for the description of

excitation properties and as charge reservoirs for the description of filling

dependencies. The VCA turns out to be a computationally cheap method which is

competitive with established cluster approaches.

\\ ( http://arxiv.org/abs/0709.4620 , 244kb)

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arXiv:0709.4675

Date: Fri, 28 Sep 2007 19:13:10 GMT (46kb)

Title: Measurement of the ac Stark shift with a guided matter-wave

interferometer

Authors: B. Deissler, K. J. Hughes, J. H. T. Burke, and C. A. Sackett

Categories: physics.atom-ph

Comments: 5 pages, three figures

\\

We demonstrate the effectiveness of a guided-wave Bose-Einstein condensate

interferometer for practical measurements. Taking advantage of the large arm

separations obtainable in our interferometer, the energy levels of the 87Rb

atoms in one arm of the interferometer are shifted by a calibrated laser beam.

The resulting phase shifts are used to determine the ac polarizability at a

range of frequencies near and at the atomic resonance. The measured values are

in good agreement with theoretical expectations. However, we observe a

broadening of the transition near the resonance, an indication of collective

light scattering effects. This nonlinearity may prove useful for the production

and control of squeezed quantum states.

\\ ( http://arxiv.org/abs/0709.4675 , 46kb)

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arXiv:0709.4577 (*cross-listing*)

Date: Fri, 28 Sep 2007 11:15:48 GMT (103kb)

Title: Sub-Kelvin Cooling of a Macroscopic Oscillator and femto-Newton Force

Measurement

Authors: F. Mueller, S. Heugel and L. J. Wang

Categories: physics.ins-det physics.optics

Comments: 5 pages, 5 figures

\\

Measuring very small forces, particularly those of a gravitational nature,

has always been of great interest, as fundamental tests of our understanding of

the physical laws. Ultra-long period mechanical oscillators, typically used in

such measurements, will have kT/2 of thermal energy associated with each degree

of freedom, owing to the equal-partition of energy. Moreover, additional

seismic fluctuations in the low frequency band can raise this equivalent

temperature significantly to 10^5 K. Recently, various methods using

opto-mechanical forces have been reported to decrease this thermal energy for

MHz, micro-cantilever oscillators, effectively cooling them. Here we show the

direct, dynamical cooling of a gram-size, macroscopic oscillator to 300 mK in

equivalent temperature - noise reduction by a factor of 10^6. By precisely

measuring the torsional oscillator's position, we dynamically provide an

external 'viscous' damping force. Such an added, dissipative force is

essentially free of noise, resulting in rapid cooling of the oscillator.

Additionally, we observe the time-dependent cooling process, at various cooling

force parameters. This parameter dependence agrees well with a simple physical

model which we provide. We further show that the device is sensitive to forces

as small as <100 fN - a force only a few percent of that typically exerted by a

single biological molecule or that observed in a typical gravity experiment. We

also demonstrate the dynamic control of the oscillator's natural frequency,

over a span of nearly two decades. The method may find important applications

in precision measurements of very weak forces.

\\ ( http://arxiv.org/abs/0709.4577 , 103kb)

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arXiv:0710.0023

Date: Fri, 28 Sep 2007 22:30:59 GMT (97kb)

Title: Pairing with Unconventional Symmetry around BCS-BEC Crossover: Fermionic

Atoms in 2D Optical Lattices to Correlated Electron Systems

Authors: Dusan Volcko and Khandker F. Quader

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

Comments: 5 pages, 4 figures

\\

We study superfluid properties of fermions on a 2D lattice using a

finite-range pairing interaction derivable from an extended Hubbard model. We

obtain signatures of unconventional pair-symmetry states, $d_{x^2-y^2}$ and

extended-s ($s^*$), in the BCS-BEC crossover region. The fermion momentum

distribution function, $v_k^2$, the ratio of the Bogoliubov coefficients,

$v_k/u_k$, and the Fourier transform of $v_k^2$ are among the properties that

are strikingly different for d- and $s^*$ symmetries in the crossover region.

Fermionic atoms in 2D optical lattices may provide a way to observe these

signatures. We discuss possible experimental ramifications of our results.

\\ ( http://arxiv.org/abs/0710.0023 , 97kb)

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arXiv:0710.0023

Date: Fri, 28 Sep 2007 22:30:59 GMT (97kb)

Title: Pairing with Unconventional Symmetry around BCS-BEC Crossover: Fermionic

Atoms in 2D Optical Lattices to Correlated Electron Systems

Authors: Dusan Volcko and Khandker F. Quader

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

Comments: 5 pages, 4 figures

\\

We study superfluid properties of fermions on a 2D lattice using a

finite-range pairing interaction derivable from an extended Hubbard model. We

obtain signatures of unconventional pair-symmetry states, $d_{x^2-y^2}$ and

extended-s ($s^*$), in the BCS-BEC crossover region. The fermion momentum

distribution function, $v_k^2$, the ratio of the Bogoliubov coefficients,

$v_k/u_k$, and the Fourier transform of $v_k^2$ are among the properties that

are strikingly different for d- and $s^*$ symmetries in the crossover region.

Fermionic atoms in 2D optical lattices may provide a way to observe these

signatures. We discuss possible experimental ramifications of our results.

\\ ( http://arxiv.org/abs/0710.0023 , 97kb)

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arXiv:0710.0045

Date: Sat, 29 Sep 2007 08:02:03 GMT (829kb)

Title: Quantum Entangled Dark Solitons Formed by Ultracold Atoms in Optical

Lattices

Authors: R. V. Mishmash, L. D. Carr

Categories: cond-mat.mes-hall

Comments: 4 pages, 4 figures

\\

Inspired by experiments on Bose-Einstein condensates in optical lattices, we

study the quantum evolution of dark soliton mean-field initial conditions in

the context of the Bose-Hubbard Hamiltonian. An extensive set of quantum

measures is utilized in our analysis, including von Neumann and generalized

quantum entropies, quantum depletion, and number fluctuations. We find that

quantum effects cause the soliton to fill in. Moreover, soliton-soliton

collisions become inelastic, in strong contrast to the predictions of

mean-field theory. These features show that the lifetime and collision

properties of dark solitons in optical lattices provide clear signals of

quantum effects.

\\ ( http://arxiv.org/abs/0710.0045 , 829kb)

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arXiv:0710.0208

Date: Mon, 1 Oct 2007 06:21:07 GMT (256kb)

Title: Hanbury Brown and Twiss correlations in atoms scattered from colliding

condensates

Authors: Klaus Molmer, A. Perrin, V. Krachmalnicoff, V. Leung, D. Boiron, A.

Aspect, C.I. Westbrook

Categories: cond-mat.other

Comments: 7 pages, 3 figures

\\

Low energy elastic scattering between clouds of Bose condensed atoms leads to

the well known s-wave halo with atoms emerging in all directions from the

collision zone. In this paper we discuss the emergence of Hanbury Brown and

Twiss coincidences between atoms scattered in nearly parallel directions. We

develop a simple model that explains the observations in terms of an

interference involving two pairs of atoms each associated with the elementary s

wave scattering process.

\\ ( http://arxiv.org/abs/0710.0208 , 256kb)

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arXiv:0710.0348

Date: Mon, 1 Oct 2007 18:00:27 GMT (57kb)

Title: Finite-temperature Bell test for quasiparticle entanglement in the Fermi

sea

Authors: W.-R. Hannes, M. Titov

Categories: cond-mat.mes-hall

Comments: 4 pages, 3 figures

\\

We demonstrate that the Bell test cannot be realized at finite temperatures

in the vast majority of electronic setups proposed previously for quantum

entanglement generation. This fundamental difficulty is shown to originate in a

finite probability of quasiparticle emission from Fermi-sea detectors. In order

to overcome the feedback problem we suggest a detection strategy, which takes

advantage of a resonant coupling and of an additional detector cooling. Unlike

other proposals the designed Bell test provides a possibility to determine the

critical temperature for entanglement production in the solid state.

\\ ( http://arxiv.org/abs/0710.0348 , 57kb)

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arXiv:0710.0353

Date: Mon, 1 Oct 2007 19:58:22 GMT (25kb)

Title: Trap-Imbalanced Fermion Mixtures

Authors: M. Iskin and C. J. Williams

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

Comments: 4 pages and 3 figures

\\

We analyze the ground state phases of two-component ($\uparrow$ and

$\downarrow$) population- and mass-balanced ($N_\uparrow = N_\downarrow$ and

$m_\uparrow = m_\downarrow$) but trap-imbalanced ($\omega_\uparrow \ne

\omega_\downarrow$) fermion mixtures as a function of interaction strength from

the weak attraction (BCS) to the strong attraction (BEC) limit. In the BCS

limit, we find that the unpolarized superfluid (UPS) fermions are surrounded by

unpolarized normal (UPN) fermions, and that they exist only away from the

central core of the trapping potentials where the normal fermions are partially

polarized. As the interactions increase towards unitarity, we find that the

central core first becomes a UPN, and then transitions to a UPS. Further

increasing the interactions, we find that the central UPS region expands, but

the inner superfluid and normal regions shrink towards the edges until the

entire mixture becomes a UPS in the BEC limit.

\\ ( http://arxiv.org/abs/0710.0353 , 25kb)

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arXiv:0710.0110

Date: Sun, 30 Sep 2007 06:48:05 GMT (122kb)

Title: Storage of spin squeezing in a two-component Bose-Einstein condensate

Authors: Guang-Ri Jin and Sang Wook Kim

Categories: quant-ph

Comments: 10 pages, 5 figures. This version is slightly different from the one

published in Phys. Rev. Lett

\\

Efficient control of spin squeezing in a two-component Bose-Einstein

Condensate is studied by rapidly turning-off the external field at a time that

maximal spin squeezing appears. We show that strong reduction of spin

fluctuation can be maintained in a nearly fixed direction for a long time. We

explain the underlying physics unambiguously, and present analytical

expressions of the maximal-squeezing time.

\\ ( http://arxiv.org/abs/0710.0110 , 122kb)

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arXiv:0710.0112

Date: Sun, 30 Sep 2007 07:24:28 GMT (63kb)

Title: Improvement of conversion efficiency of atom-molecule Bose-Einstein

condensate

Authors: Guang-Ri Jin and Sang Wook Kim

Categories: quant-ph

Comments: 4 pages, 4 figures. To be appeared in J. Korean Phys. Society (JKPS)

\\

We investigate the stimulated Raman adiabatic passage in two-color

photoassociation for a atom-molecule Bose-Einstein condensate. By applying two

time-varying Guassian laser pulses that fulfill generalized two-photon

resonance condition, we obtain highly efficient atom-molecule conversion. The

efficiency depends on the free-bound detuning and the delay time between the

two pulses. By adjusting the parameters optimally, we achieve 92% conversion

efficiency.

\\ ( http://arxiv.org/abs/0710.0112 , 63kb)

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arXiv:0710.0278

Date: Mon, 1 Oct 2007 12:46:41 GMT (180kb)

Title: Demonstration of fractional statistics of anyons in the Kitaev

lattice-spin model

Authors: Chao-Yang Lu, Wei-Bo Gao, Otfried G\"uhne, Xiao-Qi Zhou, Zeng-Bing

Chen, Jian-Wei Pan

Categories: quant-ph

Comments: 13 pages, double space, 4 figures. Comments will be appreciated

\\

In two dimensions, the laws of physics permit the existence of exotic

quasiparticles--anyons--that do not fit into the usual categories of fermions

and bosons, but obey a new form of fractional statistics. They have been

predicted to live as excitations in fractional quantum Hall systems. Quantum

states with anyonic excitations can also be artificially designed in model

systems that have highly nontrivial ground states with topological order. A

prominent example is the Kitaev lattice-spin models, which opened the avenue of

fault-tolerant topological quantum computing. Demonstration of the anyonic

fractional statistics is not only of fundamental interest, but also a

cornerstone of the emerging field of topological quantum computation. While

there is fast progress in the theoretical proposals, an unambiguous observation

of fractional statistics associated with anyon braiding still remained a real

experimental challenge. On the one hand, although some signatures have been

observed in the fractional quantum Hall systems, these experiments did not

resolve individual anyons. On the other hand, controlling cold atomic or

moleculargases in optical lattices to realize the spin models is still beyond

the current experimental capabilities. Here we report the demonstration of the

fractional statistics of anyons by simulation of the Kitaev lattice-spin model

on a six-photon graph state. Our method is to first create the ground state and

excited state of the model Hamiltonian, and then implement the braiding and

fusion operations by single-qubit rotations. Our experimental platform could

also be seen as a quantum simulator, with good controllability and purity,

which may be promising for future studies of quantum many-body physics.

\\ ( http://arxiv.org/abs/0710.0278 , 180kb)

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arXiv:0710.0285

Date: Mon, 1 Oct 2007 18:59:42 GMT (483kb)

Title: Quantum-limited metrology with product states

Authors: Sergio Boixo, Animesh Datta, Steven T. Flammia, Anil Shaji, Emilio

Bagan, and Carlton M. Caves

Categories: quant-ph

Comments: 15 pages, 6 figures

\\

We study the performance of initial product states of n-body systems in

generalized quantum metrology protocols that involve estimating an unknown

coupling constant in a nonlinear k-body (k << n) Hamiltonian. We obtain the

theoretical lower bound on the uncertainty in the estimate of the parameter.

For arbitrary initial states, the lower bound scales as 1/n^k, and for initial

product states, it scales as 1/n^(k-1/2). We show that the latter scaling can

be achieved using simple, separable measurements. We analyze in detail the case

of a quadratic Hamiltonian (k = 2), implementable with Bose-Einstein

condensates. We formulate a simple model, based on the evolution of

angular-momentum coherent states, which explains the O(n^(-3/2)) scaling for k

= 2; the model shows that the entanglement generated by the quadratic

Hamiltonian does not play a role in the enhanced sensitivity scaling. We show

that phase decoherence does not affect the O(n^(-3/2)) sensitivity scaling for

initial product states.

\\ ( http://arxiv.org/abs/0710.0285 , 483kb)

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arXiv:0710.0086

Date: Sat, 29 Sep 2007 19:04:24 GMT (273kb)

Title: An Optical Lattice Clock with Spin-polarized 87Sr Atoms

Authors: Xavier Baillard (SYRTE), Mathilde Fouch\'e (SYRTE), Rodolphe Le Targat

(SYRTE), Philip G. Westergaard (SYRTE), Arnaud Lecallier (SYRTE),

Fr\'ed\'eric Chapelet (SYRTE), Michel Abgrall (SYRTE), Giovanni D. Rovera

(SYRTE), Philippe Laurent (SYRTE), Peter Rosenbusch (SYRTE), S\'ebastien Bize

(SYRTE), Giorgio Santarelli (SYRTE), Andr\'e Clairon (SYRTE), Pierre Lemonde

(SYRTE), Gesine Grosche (PTB), Burghard Lipphardt (PTB), Harald Schnatz (PTB)

Categories: physics.atom-ph

Proxy: ccsd hal-00175653

\\

We present a new evaluation of an 87Sr optical lattice clock using spin

polarized atoms. The frequency of the 1S0-3P0 clock transition is found to be

429 228 004 229 873.6 Hz with a fractional accuracy of 2.6 10^{-15}, a value

that is comparable to the frequency difference between the various primary

standards throughout the world. This measurement is in excellent agreement with

a previous one of similar accuracy.

\\ ( http://arxiv.org/abs/0710.0086 , 273kb)

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arXiv:0710.0522

Date: Tue, 2 Oct 2007 13:19:42 GMT (712kb)

Title: Localisation and Delocalisation of Ultracold Bosonic Atoms in Finite

Optical Lattices

Authors: Dirk-S\"oren L\"uhmann, Kai Bongs, Klaus Sengstock, Daniela Pfannkuche

Categories: cond-mat.other

Comments: 8 pages, 10 figures

\\

We study bosonic atoms in small optical lattices by exact diagonalisation and

observe a striking similarity to the superfluid to Mott insulator transition in

macroscopic systems. The momentum distribution, the formation of an energy gap

and the pair correlation function show only a weak size dependence. For

non-commensurate filling we reveal a mixture of localised and delocalised

particles, which is sensitive to lattice imperfections. Breaking the lattice

symmetry causes a Bose glass like behaviour. We discuss the nature of excited

states and orbital effects by using a multi-band diagonalisation technique.

\\ ( http://arxiv.org/abs/0710.0522 , 712kb)

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arXiv:0710.0607

Date: Tue, 2 Oct 2007 19:28:14 GMT (660kb)

Title: Localized modes of binary mixtures of Bose-Einstein condensates in

nonlinear optical lattices

Authors: F. Kh. Abdullaev, A. Gammal, M. Salerno, Lauro Tomio

Categories: cond-mat.other

Comments: 13 pages, 14 figures

\\

The properties of the localized states of a two component Bose-Einstein

condensate confined in a nonlinear periodic potential [nonlinear optical

lattice] are investigated. We reveal the existence of new types of solitons and

study their stability by means of analytical and numerical approaches. The

symmetry properties of the localized states with respect to the NOL are also

investigated. We show that nonlinear optical lattices allow the existence of

bright soliton modes with equal symmetry in both components, bright localized

modes of mixed symmetry type, as well as, dark-bright bound states and bright

modes on periodic backgrounds. In spite of the quasi 1D nature of the problem,

the fundamental symmetric localized modes undergo a delocalizing transition

when the strength of the nonlinear optical lattice is varied. This transition

is associated with the existence of an unstable solution, which exhibits a

shrinking (decaying) behavior for slightly overcritical (undercritical)

variations in the number of atoms.

\\ ( http://arxiv.org/abs/0710.0607 , 660kb)

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arXiv:0710.0396

Date: Mon, 1 Oct 2007 22:11:43 GMT (156kb)

Title: Higher-order splitting algorithms for solving the nonlinear

Schr\"odinger equation and their instabilities

Authors: Siu A. Chin

Categories: physics.comp-ph physics.atom-ph

Comments: 10 pages, 8 figures, submitted to Phys. Rev. E

\\

Since the kinetic and the potential energy term of the real time nonlinear

Schr\"odinger equation can each be solved exactly, the entire equation can be

solved to any order via splitting algorithms. We verified the fourth-order

convergence of some well known algorithms by solving the Gross-Pitaevskii

equation numerically. All such splitting algorithms suffer from a latent

numerical instability even when the total energy is very well conserved. A

detail error analysis reveals that the noise, or elementary excitations of the

nonlinear Schr\"odinger, obeys the Bogoliubov spectrum and the instability is

due to the exponential growth of high wave number noises caused by the

splitting process. For a continuum wave function, this instability is

unavoidable no matter how small the time step. For a discrete wave function,

the instability can be avoided only for $\dt k_{max}^2{<\atop\sim}2 \pi$, where

$k_{max}=\pi/\Delta x$.

\\ ( http://arxiv.org/abs/0710.0396 , 156kb)

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arXiv:0710.0692

Date: Wed, 3 Oct 2007 02:14:34 GMT (824kb)

Title: Entanglement renormalization in fermionic systems

Authors: G. Evenbly, G. Vidal

Categories: quant-ph

Comments: 5 pages, 4 figures

\\

We demonstrate, in the context of quadratic fermion lattice models in one and

two spatial dimensions, the potential of entanglement renormalization (ER) to

define a proper real-space renormalization group transformation. Our results

show, for the first time, the validity of the multi-scale entanglement

renormalization ansatz (MERA) to describe ground states in two dimensions, even

at a quantum critical point. They also unveil a connection between the

performance of ER and the logarithmic violations of the boundary law for

entanglement in systems with a one-dimensional Fermi surface. ER is recast in

the language of creation/annihilation operators and correlation matrices.

\\ ( http://arxiv.org/abs/0710.0692 , 824kb)

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arXiv:0710.0766

Date: Wed, 3 Oct 2007 11:52:30 GMT (236kb,D)

Title: Atomic diffraction in counter-propagating Gaussian pulses of laser light

Authors: Tapio P. Simula, Atom Muradyan and Klaus Molmer

Categories: quant-ph

Comments: 6 pages, 5 figures

\\

We present an analysis of atomic diffraction due to the interaction of an

atomic beam with a pair of Gaussian light pulses. We derive a simple analytical

expression for the populations in different diffraction orders. The validity of

the obtained solution extends beyond the Raman-Nath regime, where the kinetic

energy associated with different diffraction peaks is neglected, into the

so-called channeling regime where accurate analytical expressions have not

previously been available for the diffraction. Comparison with experimental

results and exact numerical solutions demonstrate the validity of our

analytical formula.

\\ ( http://arxiv.org/abs/0710.0766 , 236kb)

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arXiv:0710.0733

Date: Wed, 3 Oct 2007 08:31:06 GMT (15kb)

Title: Total control over ultracold interactions via electric and magnetic

fields

Authors: Bout Marcelis, Boudewijn Verhaar, and Servaas Kokkelmans

Categories: physics.atom-ph

Comments: 4 pages, 3 figures

\\

The scattering length is commonly used to characterize the strength of

ultracold atomic interactions, since it is the leading parameter in the

low-energy expansion of the scattering phase shift. Its value can be modified

via a magnetic field, by using a Feshbach resonance. However, the effective

range term, which is the second parameter in the phase shift expansion,

determines the width of the resonance and gives rise to important properties of

ultracold gases. Independent control over this parameter is not possible by

using a magnetic field only. We demonstrate that a combination of magnetic and

electric fields can be used to get independent control over both parameters,

which leads to full control over elastic ultracold interactions.

\\ ( http://arxiv.org/abs/0710.0733 , 15kb)

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arXiv:0710.0927

Date: Thu, 4 Oct 2007 06:46:57 GMT (165kb)

Title: Optical pumping via incoherent Raman transitions

Authors: A. D. Boozer, R. Miller, T. E. Northup, A. Boca, and H. J. Kimble

Categories: quant-ph

Comments: 8 pages, 4 figures

\\

A new optical pumping scheme is presented that uses incoherent Raman

transitions to prepare a trapped Cesium atom in a specific Zeeman state within

the 6S_{1/2}, F=3 hyperfine manifold. An important advantage of this scheme

over existing optical pumping schemes is that the atom can be prepared in any

of the F=3 Zeeman states. We demonstrate the scheme in the context of cavity

quantum electrodynamics, but the technique is equally applicable to a wide

variety of atomic systems with hyperfine ground-state structure.

\\ ( http://arxiv.org/abs/0710.0927 , 165kb)

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arXiv:0710.1081

Date: Thu, 4 Oct 2007 19:52:31 GMT (92kb)

Title: Confinement effects in a guided-wave interferometer with

millimeter-scale arm separation

Authors: J. H. T. Burke, B. Deissler, K. J. Hughes and C. A. Sackett

Categories: physics.atom-ph

Comments: 14 pages, 6 figures

\\

Guided-wave atom interferometers measure interference effects using atoms

held in a confining potential. In one common implementation, the confinement is

primarily two-dimensional, and the atoms move along the nearly free dimension

under the influence of an off-resonant standing wave laser beam. In this

configuration, residual confinement along the nominally free axis can introduce

a phase gradient to the atoms that limits the arm separation of the

interferometer. We experimentally investigate this effect in detail, and show

that it can be alleviated by having the atoms undergo a more symmetric motion

in the guide. This can be achieved by either using additional laser pulses or

by allowing the atoms to freely oscillate in the potential. Using these

techniques, we demonstrate interferometer measurement times up to 72 ms and arm

separations up to 0.42 mm with a well controlled phase, or times of 0.91 s and

separations of 1.7 mm with an uncontrolled phase.

\\ ( http://arxiv.org/abs/0710.1081 , 92kb)

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The replacements:

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arXiv:0709.4123

replaced with revised version Fri, 28 Sep 2007 14:00:25 GMT (272kb)

Title: Statistics of the polariton condensate

Authors: Paolo Schwendimann and Antonio Quattropani

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

Comments: 35 pages, 4 figures

\\ ( http://arxiv.org/abs/0709.4123 , 272kb)

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arXiv:0705.1258

replaced with revised version Fri, 28 Sep 2007 19:39:39 GMT (137kb)

Title: A method of state-selective transfer of atoms between microtraps based

on the Franck-Condon Principle

Authors: A. B. Deb, G. Smirne, R. M. Godun, C. J. Foot

Categories: physics.atom-ph

Comments: 8 pages, 6 figures. Accepted for publication Journal of Physics B

(Atomic, molecular and optical physics)

\\ ( http://arxiv.org/abs/0705.1258 , 137kb)

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arXiv:cond-mat/0702505

replaced with revised version Fri, 28 Sep 2007 22:20:41 GMT (436kb)

Title: Fermi-Luttinger liquid: Spectral function of interacting one-dimensional

fermions

Authors: M. Khodas, M. Pustilnik, A. Kamenev, L.I. Glazman

Categories: cond-mat.mes-hall

\\ ( http://arxiv.org/abs/cond-mat/0702505 , 436kb)

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arXiv:0704.3047

replaced with revised version Mon, 1 Oct 2007 12:56:36 GMT (949kb)

Title: Observation of atom pairs in spontaneous four wave mixing of two

colliding Bose-Einstein Condensates

Authors: A. Perrin (LCFIO), H. Chang (LCFIO), V. Krachmalnicoff (LCFIO), M.

Schellekens (LCFIO), D. Boiron (LCFIO), A. Aspect (LCFIO), C. I. Westbrook

(LCFIO)

Categories: quant-ph

Proxy: ccsd hal-00142991

\\ ( http://arxiv.org/abs/0704.3047 , 949kb)

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arXiv:0704.0291 (*cross-listing*)

replaced with revised version Tue, 2 Oct 2007 01:38:13 GMT (324kb)

Title: Approaching the Heisenberg limit in an atom laser

Authors: M. Jeppesen, J. Dugu\'e, G. R. Dennis, M. T. Johnsson, C. Figl, N. P.

Robins and J. D. Close

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

Comments: Corrected analysis, added figure

\\ ( http://arxiv.org/abs/0704.0291 , 324kb)

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arXiv:quant-ph/0701167

replaced with revised version Tue, 2 Oct 2007 12:13:46 GMT (636kb)

Title: Cold Atom Physics Using Ultra-Thin Optical Fibers: Light-Induced Dipole

Forces and Surface Interactions

Authors: G. Sagu\'e, E. Vetsch, W. Alt, D. Meschede and A. Rauschenbeutel

Categories: quant-ph

Comments: 4 pages, 4 figures. Accepted for publication in PRL

\\ ( http://arxiv.org/abs/quant-ph/0701167 , 636kb)

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arXiv:physics/0701272

replaced with revised version Tue, 2 Oct 2007 17:44:06 GMT (578kb)

Title: Experimental single-impulse magnetic focusing of launched cold atoms

Authors: David A. Smith, Aidan S. Arnold, Matthew J. Pritchard and Ifan G.

Hughes

Categories: physics.atom-ph physics.optics

Comments: Substantially revised to incorporate referee suggestions. 10 pages, 5

figures

\\ ( http://arxiv.org/abs/physics/0701272 , 578kb)

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arXiv:0708.2257

replaced with revised version Wed, 3 Oct 2007 17:25:15 GMT (412kb)

Title: Dynamics of Atom-Field Entanglement from Exact Solutions: Towards Strong

Coupling and Non-Markovian Regimes

Authors: Nick Cummings, B. L. Hu

Categories: quant-ph

Comments: 12 pages, 5 figures; minor changes in grammar, wording, and

formatting. One unnecessary figure removed. Figure number revised (no longer

counts subfigures separately)

\\ ( http://arxiv.org/abs/0708.2257 , 412kb)

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arXiv:0709.2132

replaced with revised version Wed, 3 Oct 2007 15:28:37 GMT (177kb)

Title: Dynamics of vortices in weakly interacting Bose-Einstein condensates

Authors: Alexander Klein, Dieter Jaksch, Yanzhi Zhang and Weizhu Bao

Categories: quant-ph

Comments: 8 pages, 7 figures, one reference updated, typos corrected

Journal-ref: Phys. Rev. A 76, 043602 (2007)

DOI: 10.1103/PhysRevA.76.043602

\\ ( http://arxiv.org/abs/0709.2132 , 177kb)

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arXiv:0706.2855

replaced with revised version Thu, 4 Oct 2007 08:27:10 GMT (22kb)

Title: Crystalline phase of strongly interacting Fermi mixtures

Authors: D. S. Petrov, G. E. Astrakharchik, D. J. Papoular, C. Salomon, G. V.

Shlyapnikov

Categories: cond-mat.stat-mech

Comments: 4 pages, 1 color figure, published version

Report-no: NSF-KITP-07-132

Journal-ref: Phys. Rev. Lett. 99, 130407 (2007)

DOI: 10.1103/PhysRevLett.99.130407

\\ ( http://arxiv.org/abs/0706.2855 , 22kb)

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arXiv:cond-mat/0702569 (*cross-listing*)

Date: Sat, 24 Feb 2007 14:20:32 GMT (20kb)

Date (revised v2): Mon, 14 May 2007 09:39:55 GMT (20kb)

Date (revised v3): Thu, 2 Aug 2007 04:04:31 GMT (23kb)

Title: Quantum rearrangement and self-consistent BCS-BEC crossover

thermodynamics

Authors: Ji-sheng Chen, Chuan-ming Cheng, Jia-rong Li, Yan-ping Wang

Categories: cond-mat.stat-mech hep-ph nucl-th quant-ph

Comments: published version revised according to comments; a few typos fixed

and references updated

Journal-ref: Phys. Rev. A 76, 033617 (2007)

DOI: 10.1103/PhysRevA.76.033617

\\

Based on previous works, analytical calculational procedures for dealing with

the strongly interacting fermions ground state are further developed through a

medium dependent potential in terms of the Bethe-Peierls contact interaction

model. The methods are exact in the unitary limit regime and they lead to the

self-consistent equations analogous to the Hartree ones. The single particle

energy spectrum rearrangement effects on the thermodynamics due to the

Hugenholtz-van Hove theorem constraint are addressed. These effects lead to an

additional instantaneous correlation potential contribution to the system

physical chemical potential and pressure, i.e., equation of state, which

enforces the classical thermodynamic consistency. The Dyson-Schwinger equations

represent implicitly the various Bethe-Goldstone expansion ones. In a

thermodynamically self-consistent way, the universal dimensionless factor is

analytically calculated to be $\xi=\049$, which defines the ratio of the

unitary fermions energy density to that of the ideal non-interacting ones at

T=0.

\\ ( http://arxiv.org/abs/cond-mat/0702569 , 23kb)

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arXiv:quant-ph/0703199

replaced with revised version Thu, 4 Oct 2007 09:43:10 GMT (706kb)

Title: Bose-Einstein condensate coupled to a nanomechanical resonator on an

atom chip

Authors: Philipp Treutlein, David Hunger, Stephan Camerer, Theodor W. H\"ansch,

and Jakob Reichel

Categories: quant-ph

Comments: published version (5 pages, 3 figures)

Journal-ref: Phys. Rev. Lett. 99, 140403 (2007)

\\ ( http://arxiv.org/abs/quant-ph/0703199 , 706kb)

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arXiv:0708.0253

replaced with revised version Thu, 4 Oct 2007 00:42:59 GMT (114kb)

Title: Many-body quantum coherence and interaction blockade in Josephson-linked

Bose-Einstein condensates

Authors: Chaohong Lee, Libin Fu, Yuri S. Kivshar

Categories: quant-ph

Comments: 6 pages, 6 figures

\\ ( http://arxiv.org/abs/0708.0253 , 114kb)

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arXiv:0707.2015

replaced with revised version Thu, 4 Oct 2007 18:04:36 GMT (152kb)

Title: Trapping of ultracold polar molecules with a Thin Wire Electrostatic

Trap

Authors: J. Kleinert, C. Haimberger, P. J. Zabawa, and N. P. Bigelow

Categories: physics.atom-ph

Comments: 4 pages, 3 figures

DOI: 10.1103/PhysRevLett.99.143002

\\ ( http://arxiv.org/abs/0707.2015 , 152kb)

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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 Oct 29 2007 - 22:41:14 EST

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