Bogoliubov excitations in the quasiperiodic kicked rotor: stability of a kicked condensate and the quasi-insulator-metal transition

TL;DR

This paper investigates the stability and excitations of a Bose-Einstein condensate in a quasiperiodic kicked rotor, revealing how interactions lead to Bogoliubov excitations and affect the transition between insulating and metallic behaviors.

Contribution

It provides a detailed analysis of Bogoliubov excitations and condensate depletion in a quasiperiodic kicked rotor, highlighting the conditions under which the transition remains observable.

Findings

Bogoliubov excitations appear with increased interactions.

Condensate depletion influences the transition observation.

Subdiffusive behavior is not observed in the stable region.

Abstract

We study the dynamics of a Bose-Einstein condensate in the quasiperiodic kicked rotor described by a Gross-Pitaevskii equation with periodic boundary conditions. As the interactions are increased, Bogoliubov excitations appear and deplete the condensate; we characterize this instability by considering the population of the first Bogoliubov mode, and show that it does not prevent, for small enough interaction strengths, the observation of the transition. However, the predicted subdiffusive behavior is not observed in the stable region. For higher interaction strengths, the condensate may be strongly depleted before this dynamical regimes set in.