Emergence of steady currents due to strong prethermalization
Xiansong Xu, Chu Guo, Dario Poletti
Abstract
A steady current between baths is a manifestation of the prethermalization phenomenon, a quasiequilibrium dynamic process with weak breaking of conserved quantities. We consider two finite nonintegrable many-body baths, each following the eigenstate thermalization hypothesis and each prepared in a random product state with fixed and different energy constraints, i.e., within the mean energy ensemble. Such an initialization, not being constrained to superpositions or mixtures of many-body eigenstates, opens the door to experimental realization and also significantly simplifies numerical simulations. We show that such a dynamic process is typical as the current variance decreases exponentially with respect to the size of baths. We also demonstrate that the emerging current is prethermalized in a strong sense, analogous to strong thermalization, meaning that the current values stay close to the microcanonical one most of the time.