  We theoretically investigate the trARPES spectrum and optical Hall
conductivity in periodically driven twisted bilayer graphene, considering both
steady-state and "projected" occupations of the Floquet state. In periodically
driven pre-thermalized systems, steady-state occupation of Floquet states is
predicted to occur when coupled to a bath, while these states have projected
occupation instantaneously after the driving starts. We study how these two
regimes can give markedly different responses in optical transport properties.
In particular, our results show that steady-state occupation leads to
near-quantized optical Hall conductivity for a range of driving parameters in
twisted bilayer graphene, whereas projected occupation leads to non-quantized
values. We discuss the experimental feasibility of probing such non-equilibrium
states in twisted bilayer graphene.
