Binary Bose–Einstein condensates in a disordered time-dependent potential

Abstract

We study the non-equilibrium evolution of binary Bose-Einstein condensates in the presence of weak random potential with a Gaussian correlation function using the time-dependent perturbation theory. We apply this theory to construct a closed set of equations that highlight the role of the spectacular interplay between the disorder and the interspecies interactions in the time evolution of the density induced by disorder in each component. It is found that this latter increases with time favoring localization of both species. The time scale at which the theory remains valid depends on the respective system parameters. We show analytically and numerically that such a system supports a steady state that periodically changing during its time propagation. The obtained dynamical corrections indicate that disorder may transform the system into a stationary out-of-equilibrium states. Understanding this time evolution is pivotal for the realization of Floquet condensates.

Dynamic evolution of expanding Bose–Einstein condensates in the presence of a three-dimensional random optical speckle potential

“…In addition, it has been found that the transport of atomic matter waves in 3D media is significantly affected by varying the disorder strength when approaching to the mobility edge [10,[21][22][23]. Most recently, the out-of-equilibrium dynamics of interacting disordered systems has been analyzed in [24,25]. On the other hand, the diffusion of an expanding condensate has been widely explored in both Bose and Fermi quantum gases (see e.g.…”

Self-bound liquid droplets in one-dimensional optical speckle potentials

“…droplet depletion induced by the disorder potential) arises from the accumulation of density near the potential minima and density depletion around the maxima. It is defined as [30,31,33]…”

“…[22][23][24][25][26][27][28]). Nonetheless, the physics of Bose-Bose mixtures in disorder is still not completely understood due to the coupling between the various components which introduces extra degrees of freedom leading to unpredictable behavior and disclosing novel phase transitions [29][30][31]). Most recently the ground-state properties of quantum droplets in 3D and 2D disordered potentials have been investigated in [32,33].…”

Self-bound droplets with uncorrelated disordered potentials

“…In the case of ordinary BECs, the peculiar interplay of disorder and interactions plays a crucial role in understanding complex phenomena and quantum phases in ultracold gases namely: the Bose glass [27][28][29][30][31], Anderson localization [32][33][34][35][36][37][38][39][40][41], disordered BEC in optical lattices [42][43][44][45], the superglass phase (see e.g [46]), and dipolar BEC in random potentials [47][48][49][50][51][52][53]. Recently, we discussed the properties of movable and immovable disordered Bose-Bose mixtures [54][55][56][57][58].…”