title: Equilibrium states of generic quantum systems subject to periodic driving.
abstract: When a closed quantum system is driven periodically with period T, it approaches a periodic state synchronized with the drive in which any local observable measured stroboscopically approaches a steady value. For integrable systems, the resulting behavior is captured by a periodic version of a generalized Gibbs ensemble. By contrast, here we show that for generic nonintegrable interacting systems, local observables become independent of the initial state entirely. Essentially, this happens because Floquet eigenstates of the driven system at quasienergy ω(α) consist of a mixture of the exponentially many eigenstates of the undriven Hamiltonian, which are thus drawn from the entire extensive undriven spectrum. This is a form of equilibration which depends only on the Hilbert space of the undriven system and not on any details of its Hamiltonian.
authors.affiliation: Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany.
authors.forename: Achilleas
authors.initials: A
authors.lastname: Lazarides
authors.affiliation: Theoretical Physics Department, Indian Association for the Cultivation of Science, Kolkata 700032, India.
authors.forename: Arnab
authors.initials: A
authors.lastname: Das
authors.affiliation: Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany.
authors.forename: Roderich
authors.initials: R
authors.lastname: Moessner
mesh_terms: D011789:Quantum Theory; D013696:Temperature