Thermalization of light-driven Bloch electrons coupled to a dissipative bosonic environment: A Schwinger-Keldysh field theory approach.

We study the thermalization dynamics of light-driven Bloch electrons in a tight-binding one-dimensional lattice which are suddenly coupled to a dissipative environment. The environment consists of infinitely many bosonic modes that mediate an all-to-all interaction between lattice sites. The bath degrees of freedom are integrated out from the Schwinger-Keldysh functional integral exactly, producing an effective action in terms of electrons only. By performing a second-order perturbative expansion on such an effective action, we compute the nonequilibrium Keldysh Green's functions. From these, we extract the electronic distribution function and the single-particle density of states as a function of time.