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.