Description
Periodically driven quantum systems are able to host novel
phases not
found in equilibrium, such as topological Floquet states or time
crystals. Alternatively, one can use the periodic drive to
engineer
new band structures or interactions. In both cases integrability
breaking terms are generally present, and the absence of
conserved
quantities tend to cause the system to heat up to an effectively
infinite temperature. Thus, at first sight, it appears as if
interacting Floquet systems have a rather limited phase
structure.
However, it is possible to use time-dependent transformations to
remove almost all time-dependence from the Hamiltonian,
approximately
mapping it onto a system in thermal equilibrium. This
approach can be
valid up to exponentially long times, after which thermalization
occurs. I will discuss our recent numerical results on symmetry
breaking prethermal states in spin systems, and the
connections to
experimental realizations in cold atoms or solid state systems.
