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

Date: Tue, 31 Jul 2007 17:06:39 +1000 (EST)

Date: Tue, 31 Jul 2007 17:06:39 +1000 (EST)

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

Hello again,

I'm very pleased to say that you are now entirely up to date (as at the end of

last week!) This is a weight off my mind... my wife is due to give birth to our

second child any day now and I would had to leave you in the lurch!

Quite a few interesting papers this week... 24 new preprints and 7 replacements:

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arXiv:0707.3065

Date: Fri, 20 Jul 2007 12:58:52 GMT (271kb)

Title: Exact vortex nucleation and cooperative vortex tunneling in dilute BECs

Authors: M.I. Parke, N.K. Wilkin, J.M.F. Gunn and A. Bourne

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

Comments: 4 pages, 1 figure

\\

With the imminent advent of mesoscopic rotating BECs in the lowest Landau

level (LLL) regime, we explore LLL vortex nucleation. An exact many-body

analysis is presented in a weakly elliptical trap for up to 400 particles.

Striking non-mean field features are exposed. For example, near the critical

rotation frequency the energy levels group in neighbouring pairs, approaching

each other with exponential accuracy. A physical interpretation is provided by

requantising a mean field theory, revealing two vortices {\em cooperatively}

tunneling between classically degenerate energy minima. The variation of the

tunnel splitting near the nucleation frequency is well described in terms of

variation with frequency, particle number and ellipticity.

\\ ( http://arxiv.org/abs/0707.3065 , 271kb)

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arXiv:0707.3131

Date: Fri, 20 Jul 2007 19:14:19 GMT (229kb)

Title: Dynamics of Bloch Oscillations in Disordered Lattice Potentials

Authors: T. Schulte, S. Drenkelforth, G. Kleine B\"uning, W. Ertmer, J. Arlt,

M. Lewenstein, and L. Santos

Categories: cond-mat.other cond-mat.dis-nn

\\

We present a detailed analysis of the dynamics of Bloch oscillations of

Bose-Einstein condensates in disordered lattice potentials. Due to the disorder

and the interparticle interactions these oscillations undergo a dephasing,

reflected in a damping of the center of mass oscillations, which should be

observable under realistic experimental conditions. The interplay between

interactions and disorder is far from trivial, ranging from an

interaction-enhanced damping due to modulational instability for strong

interactions, to an interaction-reduced damping due to a dynamical screening of

the disorder potential.

\\ ( http://arxiv.org/abs/0707.3131 , 229kb)

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arXiv:0707.2963

Date: Thu, 19 Jul 2007 20:33:13 GMT (238kb,D)

Title: Two-body transients in coupled atomic-molecular BECs

Authors: Pascal Naidon, Eite Tiesinga and Paul S. Julienne

Categories: physics.atom-ph

Comments: 4 pages, 3 figures

\\

We discuss the dynamics of an atomic Bose-Einstein condensate when pairs of

atoms are converted into molecules by single-color photoassociation. Three main

regimes are found and it is shown that they can be understood on the basis of

time-dependent two-body theory. In particular, the so-called rogue dissociation

regime [Phys. Rev. Lett., 88, 090403 (2002)], which has a density-dependent

limit on the photoassociation rate, is identified with a transient regime of

the two-atom dynamics exhibiting universal properties. Finally, we illustrate

how these regimes could be explored by photoassociating condensates of

alkaline-earth atoms.

\\ ( http://arxiv.org/abs/0707.2963 , 238kb)

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arXiv:0707.3003

Date: Fri, 20 Jul 2007 06:21:40 GMT (591kb)

Title: Energy Dependence of Scattering Ground State Polar Molecules

Authors: Christopher Ticknor

Categories: physics.atom-ph

\\

We explore the total cross section of ground state polar molecules in an

electric field at various energies, focusing on RbCs and RbK. An external

electric field polarizes the molecules and induces strong dipolar interactions

leading to non-zero partial waves contributing to the scattering even as the

collision energy goes to zero. This results in the need to compute scattering

problems with many different values of total M to converge the total cross

section. An accurate and efficient approximate total cross section is

introduced and used to study the low field temperature dependence. To

understand the scattering of the polar molecules we compare a semi-classical

cross section with quantum unitarity limit. This comparison leads to the

ability to characterize the scattering based on the value of the electric field

and the collision energy.

\\ ( http://arxiv.org/abs/0707.3003 , 591kb)

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arXiv:0707.3117

Date: Fri, 20 Jul 2007 18:14:25 GMT (229kb)

Title: Cavity cooling of a nanomechanical resonator by light scattering

Authors: Ivan Favero and Khaled Karrai

Categories: physics.optics

Comments: 4 pages, 1 figure

\\

We present a novel method for opto-mechanical cooling of sub-wavelength sized

nanomechanical resonators. Our scheme uses a high finesse Fabry-Perot cavity of

small mode volume, within which the nanoresonator is acting as a

position-dependant perturbation by scattering. In return, the back-action

induced by the cavity affects the nanoresonator dynamics. We investigate such

cavity cooling by scattering in two limits, namely in the lossy regime and in

the purely dispersive regime.

\\ ( http://arxiv.org/abs/0707.3117 , 229kb)

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arXiv:0707.3140

Date: Fri, 20 Jul 2007 20:14:14 GMT (53kb)

Title: Interaction-controlled transport of an ultracold Fermi gas

Authors: Niels Strohmaier, Yosuke Takasu, Kenneth Guenter, Robert Joerdens,

Michael Koehl, Henning Moritz, and Tilman Esslinger

Categories: cond-mat.str-el

Comments: 4 pages, 4 Postscript figures

\\

We explore the transport properties of an interacting Fermi gas in a

three-dimensional optical lattice. The center of mass dynamics of the atoms

after a sudden displacement of the trap minimum is monitored for different

interaction strengths and lattice fillings. With increasingly strong attractive

interactions the weakly damped oscillation, observed for the non-interacting

case, turns into a slow relaxational drift. Tuning the interaction strength

during the evolution allows us to dynamically control the transport behavior.

Strong attraction between the atoms leads to the formation of local pairs with

a reduced tunneling rate. The interpretation in terms of pair formation is

supported by a measurement of the number of doubly occupied lattices sites.

This quantity also allows us to determine the temperature in the lattice to be

as low as $(27\pm2)%$ of the Fermi temperature.

\\ ( http://arxiv.org/abs/0707.3140 , 53kb)

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arXiv:0707.3209

Date: Mon, 23 Jul 2007 14:50:57 GMT (61kb)

Title: Commensurability effects for fermionic atoms trapped in 1D optical

lattices

Authors: Rafael A. Molina, Jorge Dukelsky, Peter Schmitteckert

Categories: cond-mat.str-el

Comments: Accepted for publication in Physical Review Letters

\\

Fermionic atoms in two different hyperfine states confined in optical

lattices show strong commensurability effects due to the interplay between the

atomic density wave (ADW) ordering and the lattice potential. We show that

spatially separated regions of commensurable and incommensurable phases can

coexist. The commensurability between the harmonic trap and the lattice sites

can be used to control the amplitude of the atomic density waves in the central

region of the trap.

\\ ( http://arxiv.org/abs/0707.3209 , 61kb)

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arXiv:0707.3320

Date: Mon, 23 Jul 2007 06:42:28 GMT (10kb)

Title: Discontinuity in the specific heat of a weakly interacting Bose gas

Authors: Sang-Hoon Kim

Categories: cond-mat.stat-mech

Comments: 2 pages, 2 figures

\\

We produce the discontinuity in the specific heat of a homogeneous, dilute,

and weakly interacting Bose gas in a short-wavelength range with a simple

statistical method. The magnitude of the discontinuity at the phase transition

temperature is obtained as a function of the density and scattering length

analytically.

\\ ( http://arxiv.org/abs/0707.3320 , 10kb)

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arXiv:0707.3593

Date: Tue, 24 Jul 2007 16:20:54 GMT (176kb)

Title: Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS

Crossover

Authors: M. J. Wright, S. Riedl, A. Altmeyer, C. Kohstall, E. R. Sanchez

Guajardo, J. Hecker Denschlag, R. Grimm

Categories: cond-mat.other

\\

We report on experimental studies on the collective behavior of a strongly

interacting Fermi gas with tunable interactions and variable temperature. A

scissors mode excitation in an elliptical trap is used to characterize the

dynamics of the quantum gas in terms of hydrodynamic or near-collisionless

behavior. We obtain a crossover phase diagram for collisional properties,

showing a large region where a non-superfluid strongly interacting gas shows

hydrodynamic behavior. In a narrow interaction regime on the BCS side of the

crossover, we find a novel temperature-dependent damping peak, suggesting a

relation to the superfluid phase transition.

\\ ( http://arxiv.org/abs/0707.3593 , 176kb)

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arXiv:0707.3599

Date: Tue, 24 Jul 2007 16:45:19 GMT (881kb)

Title: Theory for p-Wave Feshbach Molecules

Authors: K. B. Gubbels and H. T. C. Stoof

Categories: cond-mat.supr-con

Comments: 4 pages, 2 figures

\\

We determine the physical properties of \emph{p}-wave Feshbach molecules in

doubly spin-polarized $^{40}$K and find excellent agreement with recent

experiments. We show that these molecules have a large probability $Z$ to be in

the closed channel or bare molecular state responsible for the Feshbach

resonance. In the superfluid state this allows for an observation of Rabi

oscillations between the molecular and atomic components of the Bose-Einstein

condensed pairs, which contains a characteristic sign of the quantum phase

transition that occurs as a function of applied magnetic field.

\\ ( http://arxiv.org/abs/0707.3599 , 881kb)

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arXiv:0707.3630

Date: Tue, 24 Jul 2007 21:28:44 GMT (11kb)

Title: Molecular production at a wide Feshbach resonance in Fermi-gas of cooled

atoms

Authors: Deqiang Sun, Ar. Abanov, and V.L. Pokrovsky

Categories: cond-mat.other

Comments: 4 pages, no figures

\\

The problem of molecular production from degenerate gas of fermions at a wide

Feshbach resonance, in a single-mode approximation, is reduced to the linear

Landau-Zener problem for operators. The strong interaction leads to significant

renormalization of the gap between adiabatic levels. In contrast to static

problem the close vicinity of exact resonance does not play substantial role.

Two main physical results of our theory is the high sensitivity of molecular

production to the initial value of magnetic field and generation of a large BCS

condensate distributed over a broad range of momenta in inverse process of the

molecule dissociation.

\\ ( http://arxiv.org/abs/0707.3630 , 11kb)

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arXiv:0707.3633

Date: Tue, 24 Jul 2007 20:00:30 GMT (223kb)

Title: Do mixtures of bosonic and fermionic atoms adiabatically heat up in

optical lattices?

Authors: M. Cramer, S. Ospelkaus, C. Ospelkaus, K. Bongs, K. Sengstock, J.

Eisert

Categories: cond-mat.stat-mech

Comments: 5 pages, 3 figures

\\

Mixtures of bosonic and fermionic atoms in optical lattices provide a

promising arena to study strongly correlated systems. In experiments realizing

such mixtures in the quantum degenerate regime the temperature is a key

parameter. In this work, we investigate the intrinsic heating and cooling

effects due to an entropy-preserving raising of the optical lattice potential.

We analyze this process, identify the generic behavior valid for a wide range

of parameters, and discuss it quantitatively for the recent experiments with

87Rb and 40K atoms. In the absence of a lattice, we treat the bosons in the

Hartree-Fock-Bogoliubov-Popov-approximation, including the fermions in a

self-consistent mean field interaction. In the presence of the full

three-dimensional lattice, we use a strong coupling expansion. As a result of

the presence of the fermions, the temperature of the mixture after the lattice

ramp-up is always higher than for the pure bosonic case. This sheds light onto

a key point in the analysis of recent experiments.

\\ ( http://arxiv.org/abs/0707.3633 , 223kb)

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arXiv:0707.3698

Date: Wed, 25 Jul 2007 09:55:13 GMT (614kb,D)

Title: Angular momentum exchange between coherent light and matter fields

Authors: T. P. Simula, N. Nygaard, S. X. Hu, L. A. Collins, B. I. Schneider,

and K. Molmer

Categories: cond-mat.soft

Comments: 4 pages, 4 figures

\\

Full, three dimensional, time-dependent simulations are presented

demonstrating the quantized transfer of angular momentum to a Bose-Einstein

condensate from a laser carrying orbital angular momentum in a

Laguerre-Gaussian mode. The process is described in terms of coherent Bragg

scattering of atoms from a chiral optical lattice. The transfer efficiency and

the angular momentum content of the output coupled vortex state are analyzed

and compared with a recent experiment.

\\ ( http://arxiv.org/abs/0707.3698 , 614kb)

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arXiv:0707.3760

Date: Wed, 25 Jul 2007 15:03:06 GMT (34kb)

Title: Striped phases in two dimensional dipole systems

Authors: Alessandro Giuliani, Joel L. Lebowitz and Elliott H. Lieb

Categories: cond-mat.stat-mech

Comments: 20 pages, 1 figure

\\

We prove that a system of discrete 2D in-plane dipoles with four possible

orientations, interacting via a 3D dipole-dipole interaction plus a nearest

neighbor ferromagnetic term, has periodic striped ground states. As the

strength of the ferromagnetic term is increased, the size of the stripes in the

ground state increases, becoming infinite, i.e., giving a ferromagentic ground

state, when the ferromagentic interaction exceeds a certain critical value. We

also give a rigorous proof of the reorientation transition in the ground state

of a 2D system of discrete dipoles with six possible orientations, interacting

via a 3D dipole-dipole interaction plus a nearest neighbor antiferromagnetic

term. As the strength of the antiferromagnetic term is increased the ground

state flips from being striped and in-plane to being staggered and

out-of-plane. An example of a rotator model with a sinusoidal ground state is

also discussed.

\\ ( http://arxiv.org/abs/0707.3760 , 34kb)

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arXiv:0707.3646

Date: Tue, 24 Jul 2007 23:19:13 GMT (316kb)

Title: Transport quantum logic gates for trapped ions

Authors: D. Leibfried, E. Knill, C. Ospelkaus and D. J. Wineland

Categories: quant-ph

Comments: 31 pages, 5 figures

\\

Many efforts are currently underway to build a device capable of large scale

quantum information processing (QIP). Whereas QIP has been demonstrated for a

few qubits in several systems, many technical difficulties must be overcome in

order to construct a large-scale device. In one proposal for large-scale QIP,

trapped ions are manipulated by precisely controlled light pulses and moved

through and stored in multizone trap arrays. The technical overhead necessary

to precisely control both the ion geometrical configurations and the laser

interactions is demanding. Here we propose methods that significantly reduce

the overhead on laser beam control for performing single and multiple qubit

operations on trapped ions. We show how a universal set of operations can be

implemented by controlled transport of ions through stationary laser beams. At

the same time, each laser beam can be used to perform many operations in

parallel, potentially reducing the total laser power necessary to carry out QIP

tasks. The overall setup necessary for implementing transport gates is simpler

than for gates executed on stationary ions. We also suggest a transport-based

two-qubit gate scheme utilizing microfabricated permanent magnets that can be

executed without laser light.

\\ ( http://arxiv.org/abs/0707.3646 , 316kb)

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arXiv:0707.3707

Date: Wed, 25 Jul 2007 10:38:03 GMT (949kb)

Title: Storing images in warm atomic vapor

Authors: M. Shuker, O. Firstenberg, R. Pugatch, A. Ron, N. Davidson

Categories: quant-ph

\\

Back in 1844 W. H. F. Talbot co-invented the photographic plate since he

wanted to capture "fairy pictures, creations of a moment, and destined as

rapidly to fade away", seen in his camera obscura. Indeed, a photographic

process, uses a photochemical or a photoelectric response in order to record

images irreversibly onto a given media. The invention of the hologram by D.

Gabor broadened this capability, by enabling the recording of both the

amplitude and phase information of a two-dimensional light field, thus enabling

for example, the reconstruction of three dimensional images. Here we report a

method for reversibly capturing complex three-dimensional light fields using

electromagnetically induced transparency (EIT) in room temperature rubidium

vapor. We store and retrieve a short light pulse that carries a transverse

two-dimensional image by converting the amplitude and phase of the light field

into atomic coherences. We show that both the temporal and transverse

properties of the light field are preserved. As a first example, we store

images of digits for several micro-seconds. By introducing a phase-shift

technique, equivalent to the optical method known as "phase-shift lithography",

we further show that we can significantly improve the visibility of certain

retrieved images against diffusion of the atoms, which also serves as proof

that the phase of the image was stored as well. This experiment demonstrate

that three dimensional complex light fields can be stored in alkali vapor, by

employing the storage-of-light technique using EIT. This may open the

possibility of storing an array of qubits in a single alkali vapor cell.

\\ ( http://arxiv.org/abs/0707.3707 , 949kb)

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arXiv:0707.3927

Date: Thu, 26 Jul 2007 14:12:26 GMT (49kb)

Title: Dynamic structure factor of Fermi superfluid in the BEC-BCS crossover

Authors: Tarun Kanti Ghosh

Categories: cond-mat.other

Comments: To appear in Physical Review A

\\

We consider cigar shaped Fermi superfluid in the BEC-BCS crossover. Using

polytropic form of equation of state, we derive low energy multibranch bosonic

excitations and the corresponding density fluctuations in three different

regimes along the crossover, namely weak-coupling BCS, unitarity and molecular

BEC regimes. Bragg spectroscopy can be used to probe the multibranch nature of

the low energy bosonic excitations by measuring dynamic structure factor.

Therefore, we calculate dynamic structure factor in those three different

regimes. In the Bragg spectroscopy, an actual observable is momentum imparted

to the superfluid due to the Bragg potential. We also present results of the

momentum imparted to the superfluid due to the Bragg pulses.

\\ ( http://arxiv.org/abs/0707.3927 , 49kb)

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arXiv:0707.3930

Date: Thu, 26 Jul 2007 14:28:03 GMT (57kb)

Title: Superfluid-Insulator and Roughening Transitions in Domain Walls

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: 6 pages, 7 figures

\\

We have performed quantum Monte Carlo simulations to investigate the

superfluid behavior of one- and two-dimensional interfaces separating

checkerboard solid domains. The system is described by the hard-core

Bose-Hubbard Hamiltonian with nearest-neighbor interaction. In accordance with

Ref.1, we find that (i) the interface remains superfluid in a wide range of

interaction strength before it undergoes a superfluid-insulator transition;

(ii) in one dimension, the transition is of the Kosterlitz-Thouless type and is

accompanied by the roughening transition, driven by proliferation of charge 1/2

quasiparticles; (iii) in two dimensions, the transition belongs to the 3D U(1)

universality class and the interface remains smooth. Similar phenomena are

expected for domain walls in quantum antiferromagnets.

\\ ( http://arxiv.org/abs/0707.3930 , 57kb)

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arXiv:0707.3984

Date: Thu, 26 Jul 2007 19:04:02 GMT (611kb)

Title: Coarse-Grained Finite-Temperature Theory for the Condensate in Optical

Lattices

Authors: Satoru Konabe and Tetsuro Nikuni

Categories: cond-mat.other

Comments: 38 pages, 2 figures. Submitted to Journal of Low Temperature Physics

\\

In this work, we derive a coarse-grained finite-temperature theory for a Bose

condensate in a one-dimensional optical lattice, in addition to a confining

harmonic trap potential. We start from a two-particle irreducible (2PI)

effective action on the Schwinger-Keldysh closed-time contour path. In

principle, this action involves all information of equilibrium and

non-equilibrium properties of the condensate and noncondensate atoms. By

assuming an ansatz for the variational function, i.e., the condensate order

parameter in an effective action, we derive a coarse-grained effective action,

which describes the dynamics on the length scale much longer than a lattice

constant. Using the variational principle, coarse-grained equations of motion

for the condensate variables are obtained. These equations include a

dissipative term due to collisions between condensate and noncondensate atoms,

as well as noncondensate mean-field. To illustrate the usefulness of our

formalism, we discuss a Landau instability of the condensate in optical

lattices by using the coarse-grained generalized Gross-Pitaevskii

hydrodynamics. We found that the collisional damping rate due to collisions

between the condensate and noncondensate atoms changes sign when the condensate

velocity exceeds a renormalized sound velocity, leading to a Landau instability

consistent with the Landau criterion. Our results in this work give an insight

into the microscopic origin of the Landau instability.

\\ ( http://arxiv.org/abs/0707.3984 , 611kb)

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arXiv:0707.3985

Date: Thu, 26 Jul 2007 19:07:12 GMT (922kb)

Title: Direct Observation of Second Order Atom Tunnelling

Authors: S. Foelling, S. Trotzky, P. Cheinet, M. Feld, R. Saers, A. Widera, T.

Mueller and I. Bloch

Categories: cond-mat.other

Comments: 18 pages, 4 figures, accepted for publication in Nature

\\

Tunnelling of material particles through a classically impenetrable barrier

constitutes one of the hallmark effects of quantum physics. When interactions

between the particles compete with their mobility through a tunnel junction,

intriguing novel dynamical behaviour can arise where particles do not tunnel

independently. In single-electron or Bloch transistors, for example, the

tunnelling of an electron or Cooper pair can be enabled or suppressed by the

presence of a second charge carrier due to Coulomb blockade. Here we report on

the first direct and time-resolved observation of correlated tunnelling of two

interacting atoms through a barrier in a double well potential. We show that

for weak interactions between the atoms and dominating tunnel coupling,

individual atoms can tunnel independently, similar to the case in a normal

Josephson junction. With strong repulsive interactions present, two atoms

located on one side of the barrier cannot separate, but are observed to tunnel

together as a pair in a second order co-tunnelling process. By recording both

the atom position and phase coherence over time, we fully characterize the

tunnelling process for a single atom as well as the correlated dynamics of a

pair of atoms for weak and strong interactions. In addition, we identify a

conditional tunnelling regime, where a single atom can only tunnel in the

presence of a second particle, acting as a single atom switch. Our work

constitutes the first direct observation of second order tunnelling events with

ultracold atoms, which are the dominating dynamical effect in the strongly

interacting regime. Similar second-order processes form the basis of

superexchange interactions between atoms on neighbouring lattice sites of a

periodic potential, a central component of quantum magnetism.

\\ ( http://arxiv.org/abs/0707.3985 , 922kb)

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arXiv:0707.3821

Date: Wed, 25 Jul 2007 20:49:28 GMT (25kb)

Title: One-way quantum computing in optical lattices with many atom addressing

Authors: Timothy P. Friesen and David L. Feder

Categories: quant-ph

Comments: 11 pages, revtex

\\

One of the fundamental conditions for one-way quantum computation (1WQC) is

the ability to make sequential measurements on isolated qubits that comprise

the highly entangled resource for 1WQC, the cluster state. This has been a

significant impediment in the implementation of 1WQC with ultracold atoms

confined in optical lattices, because the width of the measuring lasers is

generally much greater than the atomic (qubit) spacing. We demonstrate that

deterministic 1WQC is nevertheless possible, with a polynomial increase in the

number of operations, as long as the center of the beams can be positioned with

high accuracy. Extending the number of cluster atoms, the scheme is also able

to compensate for accidental measurements of an arbitrary number of nearby

qubits.

\\ ( http://arxiv.org/abs/0707.3821 , 25kb)

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arXiv:0707.3834

Date: Wed, 25 Jul 2007 22:20:27 GMT (557kb)

Title: Spin squeezing in optical lattice clocks via lattice-based QND

measurements

Authors: D. Meiser, Jun Ye, and M. J. Holland

Categories: quant-ph

\\

Quantum projection noise limits the best achievable precision of optical

atomic clocks based on lattice-confined neutral atoms. Squeezing the collective

atomic pseudo-spin via measurement of the clock state populations during Ramsey

interrogation suppresses the projection noise. We show here that the lattice

laser field can be used to perform ideal quantum nondemolition measurements

without clock shifts or decoherence and explore the feasibility of such an

approach in theory with the lattice field confined in a ring-resonator.

Detection of the motional sideband due to the atomic vibration in the lattice

wells can yield signal sizes a hundredfold above the projection noise limit.

\\ ( http://arxiv.org/abs/0707.3834 , 557kb)

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arXiv:0707.3880

Date: Thu, 26 Jul 2007 19:03:50 GMT (472kb)

Title: Progressive field-state collapse and quantum non-demolition photon

counting

Authors: Christine Guerlin (LKB - Lhomond), Julien Bernu (LKB - Lhomond),

Samuel Del\'eglise (LKB - Lhomond), Cl\'ement Sayrin (LKB - Lhomond),

S\'ebastien Gleyzes (LKB - Lhomond), Stefan Kuhr (LKB - Lhomond), Michel

Brune (LKB - Lhomond), Jean-Michel Raimond (LKB - Lhomond), Serge Haroche

(LKB - Lhomond)

Categories: quant-ph

Proxy: ccsd hal-00165431

\\

The irreversible evolution of a microscopic system under measurement is a

central feature of quantum theory. From an initial state generally exhibiting

quantum uncertainty in the measured observable, the system is projected into a

state in which this observable becomes precisely known. Its value is random,

with a probability determined by the initial system's state. The evolution

induced by measurement (known as 'state collapse') can be progressive,

accumulating the effects of elementary state changes. Here we report the

observation of such a step-by-step collapse by measuring non-destructively the

photon number of a field stored in a cavity. Atoms behaving as microscopic

clocks cross the cavity successively. By measuring the light-induced

alterations of the clock rate, information is progressively extracted, until

the initially uncertain photon number converges to an integer. The suppression

of the photon number spread is demonstrated by correlations between repeated

measurements. The procedure illustrates all the postulates of quantum

measurement (state collapse, statistical results and repeatability) and should

facilitate studies of non-classical fields trapped in cavities.

\\ ( http://arxiv.org/abs/0707.3880 , 472kb)

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arXiv:0707.3846

Date: Thu, 26 Jul 2007 00:44:52 GMT (17kb)

Title: Quantum statistical measurements of an atom laser beam

Authors: M.K. Olsen, A.S. Bradley, S.A. Haine and J.J. Hope

Categories: physics.atom-ph physics.optics

Comments: 4 pages, 2 fugures

Journal-ref: Nuclear Physics A, 790, 733c (2007)

\\

We describe a scheme, operating in a manner analogous to a reversed Raman

output coupler, for measuring the phase-sensitive quadrature statistics of an

atom laser beam. This scheme allows for the transferral of the atomic field

statistics to an optical field, for which the quantum statistics may then be

measured using the well-developed technology of optical homodyne measurement.

\\ ( http://arxiv.org/abs/0707.3846 , 17kb)

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arXiv:0704.1037

replaced with revised version Fri, 20 Jul 2007 19:26:34 GMT (590kb)

Title: Controlled collisions of a single atom and ion guided by movable

trapping potentials

Authors: Z. Idziaszek, T. Calarco, P. Zoller

Categories: quant-ph

Comments: 17 pages, 16 figures

\\ ( http://arxiv.org/abs/0704.1037 , 590kb)

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arXiv:0704.2757

replaced with revised version Fri, 20 Jul 2007 14:29:47 GMT (257kb)

Title: Polaron Physics in Optical Lattices

Authors: Martin Bruderer, Alexander Klein, Stephen R. Clark, and Dieter Jaksch

Categories: quant-ph

Comments: 4 pages, 4 figures

Journal-ref: Phys. Rev. A 76, 011605(R) (2007)

DOI: 10.1103/PhysRevA.76.011605

\\ ( http://arxiv.org/abs/0704.2757 , 257kb)

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arXiv:cond-mat/0612261

replaced with revised version Sun, 22 Jul 2007 11:32:42 GMT (310kb)

Title: Controllable diffusion of cold atoms in a harmonically driven and tilted

optical lattice: Decoherence by spontaneous emission

Authors: Navinder Singh

Categories: cond-mat.stat-mech

Comments: 7 pages, 7 figures

\\ ( http://arxiv.org/abs/cond-mat/0612261 , 310kb)

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arXiv:0707.0870

replaced with revised version Sat, 21 Jul 2007 13:41:06 GMT (1000kb)

Title: Two-Dimensional Dynamics of Ultracold Atoms in Optical Lattices

Authors: Michiel Snoek and Walter Hofstetter

Categories: cond-mat.other

Comments: 4 pages, 6 figures; references added; improved figures

\\ ( http://arxiv.org/abs/0707.0870 , 1000kb)

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arXiv:0707.1538

replaced with revised version Mon, 23 Jul 2007 00:58:10 GMT (9kb)

Title: Transition temperature of the homogeneous, dilute and weakly interacting

Bose gas in D-dimensions

Authors: Sang-Hoon Kim

Categories: cond-mat.stat-mech

Comments: 4 pages, 1 figure

\\ ( http://arxiv.org/abs/0707.1538 , 9kb)

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arXiv:0704.0386

replaced with revised version Wed, 25 Jul 2007 09:31:29 GMT (17kb)

Title: Quantum non-local effects with Bose-Einstein condensates

Authors: Franck Lalo\"e (LKB - Lhomond), William J. Mullin

Categories: quant-ph cond-mat.other

Comments: second version submitted to PRL, including changes suggested by

referees

\\ ( http://arxiv.org/abs/0704.0386 , 17kb)

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arXiv:cond-mat/0612664

replaced with revised version Thu, 26 Jul 2007 12:56:43 GMT (251kb)

Title: Vortex quantum creation and winding number scaling in a quenched spinor

Bose gas

Authors: Michael Uhlmann, Ralf Sch\"utzhold and Uwe R. Fischer

Categories: cond-mat.other

Comments: 4 pages of RevTex4, 2 figures; to appear in Physical Review Letters

\\ ( http://arxiv.org/abs/cond-mat/0612664 , 251kb)

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Till next time (whenever that is!)

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 Tue Jul 31 2007 - 17:06:39 EST

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