Speaker: Kay Brandner
Date: Feb. 15th. 16:30-
Place: Building 22, 108, (物理学会会議室)
Title: Reservoir-induced stabilisation of a periodically driven classical spin chain
Abstract:
Exploiting the rich phenomenology of periodically-driven many-body systems is notoriously
hindered by persistent heating in both the classical and quantum realm. Here, we investigate
to what extent coupling to a large thermal reservoir makes stabilisation of a non-trivial
steady state possible. To this end, we model both the system and the reservoir as classical
spin chains, where driving is applied through a rotating magnetic field, and simulate the
Hamiltonian dynamics of this setup. We find that the intuitive limits of infinite and vanishing
frequency, where the system dynamics is governed by the average and the instantaneous
Hamiltonian, respectively, can be smoothly extended into entire regimes separated only by a
small crossover region. At high frequencies, the driven system locally attains a Floquet-type
Gibbs state at the reservoir temperature. At low frequencies, a synchronised Gibbs state
emerges, whose temperature may depart significantly from that of the reservoir. This state
can only be fully described in a global picture accounting for the concurrent relaxation of the
reservoir in a fictitious magnetic field arising from the drive. Although our analysis in some
parts relies on the specific properties our setup, we argue that much of its phenomenology
should be generic for a large class of systems.