Born-Markov Approximation

The derivation of a simpler master equation requires 4 keys approximations:

1. Rotating Wave Approximation (RWA)
2. Born Approximation

     3. The initial radiation field density operator commutes with the free Hamiltonian, and the reservoir is not 

         affected by the interactions with the system

     4.  Markov Approximation:

All these 4 approximation is called Born-Markov Approximation.

-Source : Yoshihisa Yamamoto & Atac Imamoglu, Mesoscopic Quantum Optics

System-Reservoir Interaction

Interaction of a single two-level atom with a single-mode field