Fermion systems interacting with time periodic fields I. the floquet formalism adapted to the second quantization

摘要

The second quantization, adapted to the Floquet formalism to describe a sys- tem composed of fermions interacting with an external time periodic field is pre- sented. It is introduced and also it is argued the assumption that the principal quasi-energies are the only ones with the physical significance and using this as- sumption a variant of the Wick's theorem and a perturbation series, analogous to the Feynman-Dyson are obtained.