Floquet Quantum Criticality

TL;DR

This paper investigates phase transitions in one-dimensional Floquet systems, revealing they are governed by infinite-randomness fixed points and introducing a new type of domain wall linked to time-crystalline order.

Contribution

It provides a novel description of Floquet criticality using infinite randomness physics and introduces a new domain wall concept related to time-translation symmetry-breaking.

Findings

Critical points are controlled by infinite-randomness fixed points.

A new domain wall associated with Floquet time crystals is identified.

Numerical simulations confirm the theoretical predictions.

Abstract

We study transitions between distinct phases of one-dimensional periodically driven (Floquet) systems. We argue that these are generically controlled by infinite-randomness fixed points of a strong-disorder renormalization group procedure. Working in the fermionic representation of the prototypical Floquet Ising chain, we leverage infinite randomness physics to provide a simple description of Floquet (multi)criticality in terms of a new type of domain wall associated with time-translational symmetry-breaking and the formation of `Floquet time crystals'. We validate our analysis via numerical simulations of free-fermion models sufficient to capture the critical physics.