B5: The BEC-BCS crossover in a gas with controlled disorder

Artur Widera 

Disorder is ubiquitous, and it can fundamentally change the properties of quantum systems. At the same time, time-dependent drive via external potentials can realize novel nonequilibrium states of matter with fascinating properties. This project will study resonantly interacting Fermi gases in disorder potentials with controllable correlation time. Experimentally, we employ ultracold Lithium gases along the BEC-BCS crossover in optical speckle potentials. 

Using this system, we aim to understand the connection between externally controllable parameters, such as disorder strength, correlation length, or time on the one hand, and interaction strength on the superfluid transport through the potential on the other hand. Moreover, we will elucidate the role of the underlying fermion pairs for transport by entering a regime where pairs can be broken by external drive, or where the disorder potential is rendered spin-selective.