Simulating the dynamics of harmonically trapped Weyl particles with cold atoms

Abstract : During my PhD, I contributed to the design and construction of the FERMIX experiment, dedicated to the study of a 6Li-40K fermionic mixture at ultra low temperatures. Our main results are twofold. First, we developed a new sub-Doppler laser cooling scheme, taking advantage of the existence of dark states in the D1 line of alkali atoms. This so-called grey molasses allows for a phase space density up to 10^4, the highest value reported for the simultaneous laser cooling of those two species. The improvement due to this cooling step enabled the production of a quantum degenerate 40K gas in a dipole trap, with 3x10^5 atoms in two spin states at 62 nK, corresponding to 17% of the Fermi temperature. Second, introducing a canonical mapping, we showed that non-interacting ultrarelativistic particles (Weyl fermions) in a harmonic trap can be simulated by cold fermions confined in a quadrupole potential. We study experimentally, numerically and theoretically the relaxation of these systems towards a steady state which can not be described by a Boltzman distribution, but rather presents strongly anisotropic effective temperatures. This analogy also allows us to translate fundamental properties of relativistic particles in the language of cold atoms. In particular, we demonstrate that the Klein paradox is equivalent to Majorana losses. Finally, we present a theoretical study of the long range interactions between particles confined in two 2D layers immersed in a 3D atomic cloud. We show that mediated interactions can be studied experimentally by measuring the beat-note of two clouds confined in neighboring planes of an optical lattice.
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https://tel.archives-ouvertes.fr/tel-01390499
Contributor : Daniel Suchet <>
Submitted on : Wednesday, November 2, 2016 - 9:44:32 AM
Last modification on : Friday, August 31, 2018 - 9:40:02 AM
Long-term archiving on : Friday, February 3, 2017 - 12:35:11 PM

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  • HAL Id : tel-01390499, version 1

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Daniel Suchet. Simulating the dynamics of harmonically trapped Weyl particles with cold atoms. Quantum Physics [quant-ph]. Universite Pierre et Marie Curie, 2016. English. ⟨tel-01390499v1⟩

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