Dynamical synchronization transition in interacting electron systems*

Synchronization processes are a ubiquitous phenomenon in nature. We propose a new perspective centered around the topic of a novelly introduced dynamical synchronization transition (DST) 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), where 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. Using an analogy to the celebrated Kuramoto model, describing the classical synchronization of coupled pendulums, we formulate a general framework to encapsulate the induced coherent electronic order. The resulting physics is detectable as a coherent light emission at the synchronized 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.