Quarterly Report II/2022

Author: Ameneh Sheikhan

Ultracold Bose Gases in Dynamic Disorder with Tunable Correlation Time (B5)

Benjamin Nagler , Martin Will , Silvia Hiebel, Sian Barbosa, Jennifer Koch, Michael Fleischhauer, and Artur Widera

Phys. Rev. Lett. 128, 233601 (2022)

A lot is known about static disorder which leads to Anderson localization in theory and experiment. Theoretically the dynamical noise has been studied in classical models where the noise in space and time leads to a non-equilibrium phase transition to a symmetry breaking state which is controlled by both the correlation time and the correlation length of the noise. In quantum regime the steady state might be more complicated. In the paper by Nagler et al. they investigate the non-equilibrium dynamics of ultra cold Bose gas which is subjected to the dynamical disorder. In their experiment they have a cigar shaped cloud of bosonic gas of Lithium molecules where with Feshbach resonance they tune the s-wave scattering length and the binding energy. The statice disorder can be realized with a repulsive optical speckle potential which is created by sending a laser through a diffusive plate with random surface structures. To generate the dynamical disorder the laser beam is sent through two plates with random structure where one plate is rotating against the other one. Then the laser beam is focused to the atomic cloud. As the position of scatterers change in time by rotating one of the plates the induced optical potential is random in time and position with known correlation length in position and time. The intensity of the disorder is the average speckle potential in the cloud.