Dynamical synchronization transition in interacting electron systems

TL;DR

This paper explores how synchronization phenomena can be induced and controlled in interacting electron systems, using graphene under tailored laser pulses to generate and manipulate coherent electronic orders like charge density waves.

Contribution

It introduces a new perspective on ultrafast electron dynamics by applying synchronization theory, specifically the Kuramoto model, to control electronic order in graphene.

Findings

Coherent oscillations of charge density waves can be selectively generated.

Synchronization transition leads to detectable coherent light emission.

Potential for realizing Floquet states with exotic symmetries.

Abstract

Synchronization is a ubiquitous phenomenon in nature and we propose its new perspective in ultrafast dynamics in interacting electron systems. In particular, using graphene irradiated by an intense bi-circular pulse laser as a prototypical and experimental viable example, we theoretically investigate how to selectively generate a coherent oscillation of electronic order such as charge density waves (CDW). The key is to use tailored fields that match the crystalline symmetry broken by the target order. After the pump, a macroscopic number of electrons start oscillating and coherence is built up through a transition. The resulting physics is detectable as a coherent light emission at the synchronization frequency and may be used as a purely electronic way of realizing Floquet states respecting exotic space time crystalline symmetries. In the process, we also explore possible flipping of existing static CDW orders and generation of higher harmonics. The general framework for the coherent electronic order is found to be analogous with the celebrated Kuramoto model, describing the classical synchronization of coupled pendulums.