Fermionic transport through a driven quantum point contact: Breakdown of Floquet thermalization controlled by the driving frequency

We study a quantum system that consists of two fermionic chains coupled by a driven quantum point contact (QPC). The QPC contains a bond with a periodically varying tunneling amplitude. Initially, the left chain is packed with fermions, while the right one is empty. We numerically track the evolution of the system and demonstrate that, at frequencies above a certain threshold, the current through the QPC halts, and the particle imbalance between the chains remains forever. This implies a spectacular breakdown of the Floquet version of the eigenstate thermalization hypothesis that predicts a homogeneous particle density profile at large times. We confirm the effect for various driving protocols and interparticle interactions.