Bukov, Marin

Date: Thursday, February 25, 2016
Time: 10:30
Place: ETH Zurich, Hönggerberg, HPF  G 6
Host: Tilman Esslinger

Prethermalisation and Thermalisation in Periodically Driven Systems

Marin Bukov
Boston University, USA

I will present recent results on (pre-)thermalisation in periodically driven systems. In the regime of weak interactions, I will focus on the stability diagram of the 2D Bose-Hubbard model as a function of the driving frequency and amplitude, explaining how the condensate stability is enhanced by increasing the drive strength, as this decreases the bandwidth of quasiparticle excitations and thus impedes resonant absorption and heating. I will then present numerical results on the frequency dependence of energy absorption in a strongly-interacting resonantly-driven chain of hardcore bosons, where there is a stable regime at large driving frequencies in which the time evolution is governed by a local Floquet Hamiltonian that is approximately conserved out to very long times. For slow driving, on the other hand, the system becomes unstable and heats up to infinite temperature. While thermalisation is relatively fast in these two regimes(but to different “temperatures”), in the crossover between them the time evolution is slow and non-thermalising: temporal fluctuations become strong and temporal correlations long-lived. If time permits, I will give a microscopic explanation for the onset of heating in interacting Floquet systems.