Chiral anomaly in a (1+1)-dimensional Floquet system under high-frequency electric fields

We investigate the chiral anomaly in a Floquet system under a time-periodic electric field in (1+1) dimensions. Using the van~Vleck high-frequency expansion, we analytically calculate the chiral current and the pseudo-scalar condensate for massless/massive fermions and how they are balanced with the topological charge. In the high-frequency limit, we find that finite-mass effects are suppressed and the topological charge is dominated by the chirality production. Our calculations show that the in...