Fermionic formalism for driven-dissipative multi-level systems

Understand

We present a fermionic description of non-equilibrium multi-level systems.

• Our approach uses the Keldysh path integral formalism and allows us to take into account periodic drives, as well as dissipative channels.
• The technique is based on the Majorana fermion representation of spin-1/2 models which follows earlier applications in the context of spin and Kondo systems.
• We apply this formalism to problems of increasing complexity: a dissipative two-level system, a driven-dissipative multi-level atom, and a generalized Dicke model describing many multi-level atoms coupled to a single cavity.