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Cold Atoms Team
The Cold Atoms group in Toulouse was created in december 2007.
Web site http://www.quantumengineering-tlse.org/
The group consists of three permanent members:
David Guéry-Odelin (professor),
Juliette Billy (assistant professor),
Bruno Peaudecerf (CNRS researcher).
PhD students: Gabriel Chatelain and Nathan Dupont.
Postdoc: Lucas Gabardos.
The team also benefits from the help of the Research Engineer Stéphane Faure.
The team has two types of scientific activities: an experimental activity on quantum gases and a theoretical / numerical acitivity on quantum engineering and statistical physics.
The general research topics of our experimental activity deals with the manipulation of Bose-Einstein condensates (BECs) with light, and more precisely on cold atoms based quantum simulations.
BECs are obtained by cooling an ensemble of atoms to extremely low temperatures, down to a few tens of nano-Kelvin above the absolute zero. The condensate are obtained in a hybrid trap which consists in a crossed optical dipole trap superimposed to a quadrupole magnetic trap. The experimental setup produces on a daily basis pure rubidium-87 condensates of 150 000 atoms, in a stable and reproducible way.
Our group is currently investigated the rich physics of quantum gases placed in optical lattices. We have setup a new calibration method of the optical lattice depth [1], and investigated the tunneling time between adjacent sites [2].
We have also investigated the rich physics related to phase modulation of the lattice in three different regimes:
(1) at low frequency, the modulation drives a dynamical instability which generates a new quantum phase commonly referred to as the staggered state phase ; we have shown that quantum fluctuations trigger the transition and observed the role of thermal fluctuations at higher temperature [3]
(2) at resonant frequencies we have observed interband transitions and identified transition lines immune to atom-atom interactions [4].
(3) at large frequencies, we observe the renormalization of the lattice depth, and the signature of a combined effect of micromotion and interactions [5].
We are currently investigating quantum transport in disordered systems. This research line is developed in close collaboration with Bertrand Georgeot and Gabriel Lemarié from Laboratoire de Physique Théorique (Toulouse). We plan to experimentally study chaos-assisted tunneling. For this study, we will use a condensate loaded in a deep optical lattice, whose phase and amplitude will be controlled in time. This system generates a dynamical lattice with tunable spacing [6]. It will in particular play the role of a quantum simulator of Josephson junctions, isolated or coupled in arrays. It will allow us to study the relative role of interactions and tunneling in dynamical lattices and also multiple interference phenomena, such as multifractality.
Our group also explores new possibilities for observing topological structures in time-dependent lattices.
From a theoretical point of view, we continue the development of the field of Shortcut To Adiabaticity (STA) in and beyond quantum mechanics. We have demonstrated how STA solution designed in the absence of dissipation can be adapted to situation which exhibits dissipation for a large class of problems including for the generation of entangled states [7]. We have recently shown, with collaborators from ENS Lyon and Orsay university, how thermalization can be significantly accelerated. This work has led to convincing experimental demonstrations [8,9,10,11]. We have also extended the possibility opened up by STA techniques to shortcut the access to a stationary regime [12].
[1] C. Cabrera-Gutiérrez, E. Michon, V. Brunaud, T. Kawalec, A. Fortun, M. Arnal, J. Billy and D. Guéry-Odelin, Phys. Rev. A 97, 043617 (2018).
[2] A. Fortun, C. Cabrera-Gutiérrez, G. Condon, E. Michon, J. Billy and D. Guéry-Odelin, Phys. Rev. Lett. 117, 010401 (2016).
[3] E. Michon, C. Cabrera-Gutiérrez, A. Fortun, M. Berger, M. Arnal, V. Brunaud, J. Billy, C. Petitjean, P. Schlagheck, and D. Guéry-Odelin , New Journal of Physics 20, 053035 (2018).
[4] C. Cabrera-Gutiérrez, E. Michon, M. Arnal, V. Brunaud, T. Kawalec, J. Billy, D. Guéry-Odelin, arXiv:1808.00345v1 [cond-mat.quant-gas]
[5] C. Cabrera-Gutiérrez, A. Fortun, E. Michon, V. Brunaud, M. Arnal, J. Billy, D. Guéry-Odelin, arXiv: 1804.02147v1 [cond-mat.quant-gas]
[6] R. Dubertrand, J. Billy, D. Guéry-Odelin, B. Georgeot, G. Lemarié, Phys. Rev. A 94, 043621 (2016).
[7] François Impens and David Guéry-Odelin, ArXiv: 1807.02034v1 [quant-phys]
[8] D. Guéry-Odelin, J. G. Muga, M. J. Ruiz-Montero and E. Trizac, Phys. Rev. Lett. 112, 180602 (2014)
[9] I. A. Martinez, A. Petrosyan, D. Guéry-Odelin, E. Trizac, and S. Ciliberto, Nature Physics, 12, 843–846 (2016).
[10] A. Le Cunuder, I. Martinez, A. Petrosyan, D. Guéry-Odelin, E. Trizac and S. Ciliberto, Appl. Phys. Lett. 109, 113502 (2016).
[11] Marie Chupeau, Benjamin Besga, David Guéry-Odelin, Emmanuel Trizac, Artyom Petrosyan, Sergio Ciliberto, Phys. Rev. E 90, 010104(R) (2018).
[12] S. Faure, S. Ciliberto, E. Trizac, D. Guéry-Odelin, arXiv:1808.01321 [physics.class-ph]
Funding :
ANR COCOA (2018-2021), ANR STATE (2019-2021), Labex NEXT TRAFIC (2015-2018)
Collaborations:
Peter Schlagheck, Université de Liège, Belgique
Gonzalo Muga, University del Pais Basco, Bilbao, Spain
François Impens, Universidade Federal do Rio de Janeiro, Brazil
Emmanuel Trizac, Université Paris-Sud, France
Sergio Ciliberto, ENS Lyon, Lyon, France
Bertrand Georgeot, Gabriel Lemarié and Rémi Dubertrand, LPT Toulouse, France
Christian Miniatura, Singapore et INLN Nice
Naceur Gaaloul and Ernst Rasel, Leibniz Universität, Hannover, Germany
John Martin, Université de Liège, Belgique
Dima Shepelyansky, LPT Toulouse, France
Xi Chen, Shanghai university, China.