Skip to Main content Skip to Navigation

Theoretical study of quantum correlations and nonlinear fluctuations in quantum gases

Abstract : This thesis is dedicated to the study of nonlinear-driven phenomena in two quantum gases which bear important similarities: Bose-Einstein condensates of ultracold atomic vapors and “fluids of light”. In a first part, we study sonic analogues of black holes. In a Bose-Einstein condensate, it is possible to implement a stationary configuration with a current flowing from a subsonic region to a supersonic one. This mimics a black hole, since sonic excitations cannot escape the supersonic region. Besides, quantizing the phonon field leads to a sonic analogue of Hawking radiation. In this thesis, we show that a correct account of “zero modes” – overlooked so far in the context of analogue gravity – is essential for an accurate description of the Hawking process, and results in a excellent comparison with recent experimental data. In addition, we characterize the entanglement shared among quantum excitations and show that they exhibit tripartite entanglement. In a second part, we investigate the short and long time propagation of nonlinear fluids within a hydrodynamic framework and by means of mathematical methods developed by Riemann and Whitham. In particular, we study the oscillating structure and the dynamics of dispersive shock waves which arise after a wave breaking event. We obtain a weak shock theory, from which we can extract a quantitative description of experimentally relevant parameters, such as the wave breaking time, the velocity of the solitonic edge of the shock or the contrast of its fringes.
Complete list of metadatas

Cited literature [404 references]  Display  Hide  Download
Contributor : Abes Star :  Contact
Submitted on : Thursday, October 22, 2020 - 9:26:09 AM
Last modification on : Saturday, October 24, 2020 - 3:29:06 AM


Version validated by the jury (STAR)


  • HAL Id : tel-02974737, version 1



Mathieu Isoard. Theoretical study of quantum correlations and nonlinear fluctuations in quantum gases. Pattern Formation and Solitons [nlin.PS]. Université Paris-Saclay, 2020. English. ⟨NNT : 2020UPASP004⟩. ⟨tel-02974737⟩



Record views


Files downloads