Floquet Superheating

TL;DR

This paper introduces a Floquet superheating regime in driven many-body systems, where rare local fluctuations lead to long-lived prethermal states, challenging the typical infinite-temperature heating behavior.

Contribution

The study demonstrates a novel Floquet superheating phenomenon driven by rare fluctuations, with a phenomenological model explaining critical droplet sizes and long-lived non-equilibrium states.

Findings

Identification of a Floquet superheating regime

Long-lived prethermalization due to hot spot nucleation

Suppressed heating in low-energy states with potential for stabilizing non-equilibrium phases

Abstract

Periodically driven many-body systems generally heat towards a featureless 'infinite-temperature' state. As an alternative to uniform heating in a clean system, here we establish a Floquet superheating regime, where fast heating nucleates at ''hot spots" generated by rare fluctuations in the local energy with respect to an appropriate effective Hamiltonian. Striking macroscopic consequences include exceptionally long-lived prethermalization and non-ergodic bimodal distributions of macroscopic observables. Superheating is predicated on a heating rate depending strongly on the local fluctuation; in our example, this is supplied by a sharp state-selective spin-echo, where the energy absorption is strongly suppressed for low-energy states, while thermal fluctuations open up excessive heating channels. A simple phenomenological theory is developed to show the existence of a critical droplet size, which incorporates heating by the driving field as well as the heat current out of the droplet. Our results shine light on a new heating mechanism and suggest new routes towards stabilizing non-equilibrium phases of matter in driven systems.