Jean-Claude Garreau web page


	*Jean-Claude Garreau* Scientific web page

Contents:

Who am I?
How to contact me?
Sources and resources
Research interest s
Research achievements
Selected publications
Recent invited conferences and seminars

Who am I?

I was born in Barbacena (see Google Earth), a small brazilian town some 200 km from Rio de Janeiro upwards the mountains, in 1958.
I graduated in 1982 from Pontificia Universidade Catolica (this choice was not made on religious grounds) do Rio de Janeiro (PUC/RJ).
I got my M. Sc. also from PUC/RJ , working with Luiz Davidovich on intense laser field atomic ionization.

I moved to France in 1985 to prepare my Ph. D. degree in Laboratoire Kastler Brossel (then Laboratoire de Spectroscopie Hertzienne) de l'ENS, in Paris. I worked there with François Biraben and Lucile Julien on high-precision two-photon spectroscopy of the hydrogen atom. The subject of my Ph. D. thesis was a determination of the Rydberg constant, then the most precise measurement of that constant in the world.

I made a post-doc at CNET (the research center of France Télécom, now France Télécom R&D) with Ariel Levenson and Izo Abram, working on the manipulation of the quantum noise of light. We conceived and experimentally demonstrated a quantum device able to copy the features of a light beam without adding quantum noise to it, the Quantum cloning amplifier.

I joined the CNRS in 1992, and I work since then in the Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM), at Villeneuve d'Ascq (near Lille, the main city of the northeast France, 20 km from the Belgium border). I have started in 1995, with Daniel Hennequin, a new research activity in the Laboratory, centered on the dynamics of cold atoms. In 2004 I was promoted "directeur de recherche de 2e classe" au CNRS.

From 1998 on, the Quantum Chaos group, formed by Pascal Szriftgiser, Véronique Zehnlé and myself, with several Ph. D. students and post-docs, works in experimental and theoretical studies of the quantum dynamics of cold atoms in light potentials.

How to contact me?
By e-mail:

jean-claude.garreau "at" univ-lille1.fr

By phone:

+33 (0)3 33 64 49 (from abroad, do not dial "(0)")

Street address:

Bat. P5 - Laboratoire PhLAM
Université Lille 1
F-59655 Villeneuve d'Ascq cedex

Sources and resources

Cold Atoms
Quantum chaos & the kicked rotor
Dynamics in optical potentials
The Anderson model

Research interests

In my professional and passional activity as a physicist, I have had the opportunity to work in many fields, doing both theoretical and experimental research:

Current research fields
     - Experimental studies of quantum chaos with cold atoms
    - Experimental and theoretical studies of quantum transport of cold atoms in light potentials
    - Theoretical studies of the relations between quantum coherence and quantum interference

Past research fields
- Experimental and theoretical quantum optics (manipulation of the quantum noise of light, squeezing)
- Ultra-precise spectroscopy of the hydrogen atom, measurement of the Rydberg constant (Ph. D. thesis)

Programming & interfacing
- Development of Visual C++ applications (graphic applications, database applications, etc.)
- Development of experiment-interfacing C++ object libraries (GPIB, data acquisition & processing)

I have published some 47 peer-reviewed articles in international journals, which have been cited about 640 times in the scientific literature. Below, I present a selection of the papers most representative of my scientific activity.

Click here for more complete information on my current research activity.

Click here for a more complete list of recent publications.

Research achievements
	Quantum Motor: Driving arbitrary motion of a wavepacket in an optical lattice Optical lattice offer astounding possibilities of manipulating quantum atomic wavepackets, because there exists a complete arsenal of methods for technological changing the properties of the laser beams from which optical lattices are made. It is vey easy, for example, to modulate the amplitude of the potential with complicated forms, both in time and space. Using such possibilities, we analyzed and demonstrated a "quantum motor" able to drive an atomic wavepacket along an arbitrary path... ... or even to induce a rotation of the wave packet! Figure (c) above has been selected for the kaleidoscope of Physical Review A, see here. For more information, see our paper Physical Review A, 84, 043403 (2011).
	Simulating the Anderson model with cold atoms 2011: The Universality of the Anderson transition experimentally tested! We have experimentally tested one of the fundamental principles underlying the theory of phase transitions, the notion of universality. And, "cerise sur le gâteau", we have done that for the famous Anderson transition, using its quantum-chaotic analog, the quasi-periodic kicked rotor. Universality means that the critical properties of a phase-transition, characterized by its critical exponent, depends only on the symmetries of the system, and shall not depend on any "microscopic" detail (as, e.g., in the case of a disordered system, the statistics of the disorder). We have used nine sets of parameters, labeled from a to i, corresponding to different configurations of our system, and shown that the measured critical exponent is the same to a very good precision within experimental errors, as shown in the figure below: The measurement of the critical exponent is a very delicate task that used a technique known as "finite-size scaling" (for more on that see this paper) that we adapted to our problem: For more details, see Phys. Rev. Lett. 108, 095701 (2012). 2010: The critical wave function measured! *This work has been chosen as an* *"Editors suggestion" by PRL and is the object of an* *" Synopsis: Spotlighting exceptional research"* For the first time, the wave function at the critical point of a quantum phase transition has been experimentally measured and shown to display the attended scaling properties! This has been done using a cold atom analog of the Anderson model, the atomic kicked rotor. See Phys. Rev. Lett. 105, 090601 (2010). 2008-2009: The Anderson transition observed with cold atoms! *This work has been chosen as an* *"Editors suggestion" by PRL and is the object of an* *" Viewpoint: Spotlighting exceptional research"* When a quantum-chaotic kicked rotor presenting dynamical localization (DL) is perturbed by a quasiperiodic perturbation, dynamical localization is destroyed. But what is the scenario followed by this destruction? If one thinks that the well-known analogy between dynamical localization and the Anderson localization shall be universal, one shall expect that DL is preserved, but the localization length goes to infinity with the amplitude of the perturbation. Performing the experiment, we have followed that this is not the case. We observe a progressive transition from localization to a diffusive behavior that becomes stronger as the perturbation increases. This shows that the above Anderson analogy is not universal and may depend on the precise way DL is distroyed (see Phys. Rev. Lett. 97, 264101 (2006)). However, more recently, we have used a different system, in which the quasiperiodic modulation is applied as a modulation of the intensity of the kicks. In the case in which the system displays three independent frequencies (corresponding, formally, to a 3D Anderson model), we have been able to put into evidence a quantum phase transition which is the kicked-rotor temporal equivalent of the condensed matter physics Anderson metal-insulator transition (see Phys. Rev. Lett. 101, 255702 (2008). A detailed account of both the experiment and the underlying theoretical issues has been published here: Phys. Rev. A. 80, 043626 (2009).
	Reversibility and irreversibility in a quantum-chaotic system The quantum-chaotic kicked rotor presents astonishing quantum-interference effects, as that called dynamical localization. It is possible to mixt-up phases deterministically in order to suppress such quantum interference effects (see Phys. Rev. Lett. 85, 2741 (2000)). However, being deterministic, such mixing is in principle reversible: we have demonstrated it experimentally. On the other hand, decoherence is a random mixing of quantum phases, and, as such, is irreversible. We have also demonstrated that by adding spontaneous emission in a controlled way to our system, the revesibility is destroyed (see Phys. Rev. Lett. 95, 234101 (2005)).
	Quasi-classical chaos in the dynamics of a Bose-Einstein condensate Quantum mechanical evolution is usually linear, because Schrödinger equation also is. This means that in cannot display sensitivity to initial conditions and a chaotic behavior in the classical sense. That is why quantum chaos (which ususally means the behavior of a quantum system whose classical limit is chaotic) is very different of classical chaos. However, Bose-Einstein condensates are more complicated objects, because they display many-body quantum-coherent interactions that can produce to nonlinearities, e.g. in the limit of the mean-field approach of Gross-Pitaevskii equation. They are thus able in a certain sense to display sensitivity to initial conditions and a kind of quasi-classical chaos. We have recently studied this situation, and shown that the quasi-classical behavior is compatible with the Komolgorov-Arnol'd-Moser theorem (see Phys. Rev. Lett. 91, 210405 (2003)) -- see above figure, left pannel. We have also verified that the chaotic behavior is effectively associated to positive Lyapunov exponents, which proves that it is an effect of sensitivity to initial conditions. Morever, we have proposed methods for characterizing the dynamical behavior directly from experimentally accessible signals, that allow to reconstruct à local "route to quasi-classical chaos" (see Phys. Rev. Lett. 101, 144130 (2008)) -- see above figure, right pannel.
	"Sub-Fourier" resonances in a quantum chaotic system Quantum-chaotic systems, in certain conditions, can distinguish two frequencies in a time smaller that the inverse of the frequency difference. This behavior, that we loosely call "sub-Fourier" has been identified and demonstrated for the first time recently (see Phys. Rev. Lett. 89, 224101 (2002)). We are now able to explain the detail mechanims leading to such astonishing behavior in terms of dynamics of quantum-chaotic systems (see Europhys. Lett. 69, 327 (2005)).

Selected publications

Simulating the Anderson model with cold atoms
	*Interacting ultracold bosons in disordered lattices: Sensitivity of the dynamics to the initial state* Phys. Rev. E 85, 046213 (2012), with Benoît Vermersch
	*Experimental Test of Universality of the Anderson Transition* Phys. Rev. Lett. 108, 095701 (2012), with Matthias Lopez, Jean-François Clément, Pascal Szriftgiser, Dominique Delande
	*Critical State of the Anderson Transition: Between a Metal and an Insulator* Phys. Rev. Lett. 105, 090601 (2010), with Gabriel Lemarié, Hans Lignier, Dominique Delande and Pascal Szriftgiser. See Synopsis
	*Observation of the Anderson transition with atomic matter waves: Theory and experiment* Phys. Rev. A 80, 043626 (2009), with Gabriel Lemarié, Julien Chabé, Pascal Szriftgiser, Benoît Grémaud and Dominique Delande. Selected for the Virtual Journal of Atomic Quantum Fluids.
	*Experimental observation of the Anderson transition with atomic matter waves* Phys. Rev. Lett. 101, 255702 (2008), with Julien Chabé, Gabriel Lemarié, Benoît Grémaud, Dominique Delande and Pascal Szriftgiser. See Viewpoint
	*Quantum scaling laws in the onset of dynamical delocalization* Phys. Rev. Lett. 97, 264101 (2006), with Julien Chabé, Hans Lignier, Hugo Cavalcante, Dominique Delande and Pascal Szriftgiser

*Quantum chaos and quantum transport with cold atoms*
	Quantum motor: Directed wavepacket motion in an optical lattice Phys. Rev. A 84 043403 (2011) with Quentin Thommen and Véronique Zehnlé.
	*Suppression of decoherence-induced diffusion in the quantum kicked rotor* Phys. Rev. A 81, 062132 (2009), with Maxence Lepers and Véronique Zehnlé.
	*Tracking quasi-classical chaos in ultracold bose gases* Phys. Rev. Lett. 101, 144103 (2008), with Maxence Lepers and Véronique Zehnlé
	*Kicked rotor quantum resonances in position space* Phys. Rev. A 77, 043628 (2008), with Maxence Lepers and Véronique Zehnlé
	*Reversible destruction of dynamical localization* Phys. Rev. Lett 95, 234101 (2005), with Hans Lignier, Julien Chabé, Dominique Delande and Pascal Szriftgiser
	*Phase-space reconstruction of an atomic chaotic system* Phys. Rev. A 72, 033814 (2005), with Hugo Cavalcante and Carlos Renato de Carvalho
	*Quantum diffusion in the quasiperiodic kicked rotor* Europhys. Lett. 69, 327 (2005), with Hans Lignier, Pascal Szriftgiser and Dominique Delande
	*Classical chaos with Bose-Einstein condensates in tilted optical lattices* Phys. Rev. Lett. 91, 210405 (2003), with Quentin Thommen and Véronique Zehnlé
	*Wave-packet reconstruction via local dynamics in a parabolic lattice* Phys. Rev. A 63, 013416 (2003), with Quentin Thommen and Véronique Zehnlé
	*Observation of sub-Fourier resonances in a quantum-chaotic system* Phys. Rev. Lett. 89, 224101 (2002), with Pascal Szriftgiser, Jean Ringot and Dominique Delande
	*Subrecoil Raman spectroscopy of cold cesium atoms* Phys. Rev. A 65, 013403 (2002), with Jean Ringot and Pascal Szriftgiser
	*Theoretical analysis of quantum dynamics in 1D lattices: Wannier-Stark description* Phys. Rev. A 65, 053406 (2002), with Quentin Thommen and Véronique Zehnlé
	*Experimental evidence of dynamical localization and delocalization in a quasi-periodic driven system* Phys. Rev. Lett. 85, 2741 (2000), with Jean Ringot, Pascal Szriftgiser, and Dominique Delande
	*Generation of phase-coherent laser beams for Raman spectroscopy and cooling by direct current modulation of a diode laser* Eur. Phys. J. D 7, 285-288 (1999), with Jean Ringot, Yann Lecoq, and Pascal Szriftgiser

*Classical dynamics of laser-cooled atoms* *- cooling techniques*
	*Doppler cooling to the recoil limit using sharp atomic transitions with controlled quenching* JOSA B 20, 931-936 (2003), with Véronique Zehnlé
	*Continuous-wave Doppler cooling of hydrogen atoms with two-photon transitions* Phys. Rev. A 63 021402(R) (2001), with Véronique Zehnlé
	*Instabilities in a magneto-optical trap : Noise induced dynamics in an atomic system* Phys. Rev. Lett. 85, 1839-1842 (2000), with David Wilkowski, Jean Ringot, and Daniel Hennequin
	*Observation of bistability in a perturbed magneto-optical trap* Eur. J. Phys. D 2, 157-163 (1998), with David Wilkowski, and Daniel Hennequin

*Quantum coherence and quantum interference*
	*Quantum coherence generated by interference-induced state selectiveness* J. Mod. Opt. 49, 43 (2002)
	*Raman sub-recoil cooling using quantum interference* Phys. Rev. A 61, 011401(R) (2000)
	*Atomic velocity class selection using quantum interference* Phys. Rev. A 54, 4249-4258 (1996), with David Wilkowski, Daniel Hennequin, and Véronique Zehnlé
	*Quantum coherence generated by quantum interference* Phys. Rev. A 53, 486-494 (1996)

*Quantum optics and laser physics*
	*Self-similarities in the frequency-amplitude space of a loss-modulated CO2 laser* Phys. Rev. Lett. 95, 143905 (2005), with Cristian Bonatto and Jason Gallas
	*Quantum optical cloning amplifier* Phys. Rev. Lett. 70, 267-270 (1993), with Ariel Levenson, Izo Abram, Thomas Rivera, P. Fayolle, and Philippe Grangier
	*Quantum correlated twin beams* Appl. Phys. B 55, 250-257 (1992), with Ariel Levenson, Izo Abram et al.

*Metrology of fundamental constants*
	*New measurement of the Rydberg constant by two-photon spectroscopy of hydrogen Rydberg states* Phys. Rev. Lett. 62, 621-624 (1989), with François Biraben, Lucile Julien, and Maria Allegrini
	*Determination of the Rydberg constant by Doppler-free spectroscopy of hydrogen Rydberg states* Europhys. Lett. 2, 925-932 (1986), with François Biraben and Lucile Julien

*Recent invited conferences and seminars*
*June 29, 2011*	Quantum simulators: The Anderson transition case 43th EGAS Conference, Fribourg, Swiss
*June 9, 2011*	Experimental observation of the Anderson transition with cold atoms Summer School "Disordered systems: From condensed-matter physics to ultracold atomic gases", Cargèse, Corsica	PDF
*October 21, 2010*	Transition d'Anderson avec un système d'atomes froids quantiquement chaotique Laboratoire Aimé Cotton
*August 23, 2010*	Etude experimentale de la transition d'Anderson avec des atomes froids Journées de la Matière Condensée 12, Troyes
*June 5, 2010*	Quantum chaos and quantum simulators: the case of the Anderson model Experimental Chaos Conference, Lille
*November 13, 2009*	The Anderson metal-insulator transition in a quantum-chaotic system of laser-cooled atoms "Nanomagnetism, Spintronics, and Quantum Optics 2009, Rio de Janeiro, Brazil	PDF
*October 5, 2009*	Disorder and quantum chaos: The Anderson transition in a quatum-chaotic atomic system Réunion plénière du GDR “Physique Quantique Mésoscopique”, Aussois
*September 28, 2009*	Transition d'Anderson avec un système d'atomes froids quantiquement chaotique Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon	PDF
*July 9, 2008*	Observation expérimentale de la transition d’Anderson dans un système dynamique PAMO-JSM 2008, Lille	PDF
*April 10, 2008*	Experimental observation of the Anderson transition in a dynamical system Department of Physics and Astronomy, University College London, UK	PDF

v.2.2 (25/4/2012)