Many-body dynamics and gap opening in interacting periodically driven systems

TL;DR

This paper investigates how interactions influence the transient gap opening in a driven two-dimensional Dirac fermion system, revealing interaction-induced gap enhancement and discussing regimes suitable for experimental observation before heating dominates.

Contribution

It demonstrates that interactions can renormalize and enhance the dynamical gap in a periodically driven Dirac system, extending understanding of non-equilibrium topological phenomena.

Findings

Interactions enhance the quasienergy gap compared to non-interacting systems.

The study identifies regimes where dynamical gap emergence can be observed before heating effects dominate.

Interactions influence the transient dynamics and spectral properties probed by photoemission.

Abstract

We study the transient dynamics in a two-dimensional system of interacting Dirac fermions subject to a quenched drive with circularly polarized light. In the absence of interactions, the drive opens a gap at the Dirac point in the quasienergy spectrum, inducing nontrivial band topology. Here we investigate the dynamics of this gap opening process in the presence of interactions, as captured by the generalized spectral function and correlators probed by photoemission experiments. Through a mechanism akin to that known for equilibrium systems, interactions renormalize and enhance the induced gap over its value for the non-interacting system. We additionally study the heating that naturally accompanies driving in the interacting system, and discuss the regimes where dynamical gap emergence and enhancement can be probed before heating becomes significant.