Colloquium: 20 maggio 2021 ore 16:30 Prof. David Guéry-Odelin "Quantum gases in time-modulated optical lattices: from quantum control to quantum chaos and vice versa"

Abstract: 

In this talk, I propose to focus on two recent experimental results of our team obtained by shaking a Bose Einstein condensate in an optical lattice:

 

1) In the first part, I will focus the discussion on the production of s-wave scattering halos from collisions between the momentum components of a Bose–Einstein condensate released from an optical lattice which provides an interesting example of matter-wave duality. I will report on the methods we have developed to engineer those halos  [1]. More generally, we will explain a strategy to produce arbitrary quantum states using optimal control theory [2].

 

2) In the second part, I will focus on quasi-resonant modulation of the lattice depth to observe a quantum chaos transport mechanism called chaos-assisted tunneling. Under such a modulation, the classical phase space exhibits  stable islands surrounded by a large chaotic sea. The coupling between islands is mediated by delocalized Floquet states that spread over the chaotic sea. As a result, the transport between the islands exhibit sharp resonances where the tunneling rate varies by orders of magnitude over a short range of parameters. We experimentally demonstrate and characterize these resonances for the first time in a quantum system. This opens the way to new kinds of quantum simulations with long-range transport [3,4].

 

Bibliography:

 

[1] G. Chatelain, N. Dupont, M. Arnal, B. Brunaud, J. Billy, B. Peaudecerf, P. Schlagheck and D. Guéry-Odelin, New Journal of Physics 22, 123032 (2020).

 

[2] N. Dupont et al., in preparation

 

[3] M. Arnal, G. Chatelain, M. Martinez, N. Dupont, O. Giraud, D. Ullmo, B. Georgeot, G. Lemarié, J. Billy and D. Guéry-Odelin, Science Advances 6, eabc4486 (2020).

 

[4] M. Martinez, O. Giraud, D. Ullmo, J. Billy, D. Guéry-Odelin, B. Georgeot, and G. Lemarié, arXiv:2011.02557v1 [quant-ph]