Unified approach to the Bloch-Redfield theory and quantum Fokker-Planck equations

Abstract

The quantum dissipation theories of Bloch-Redfield and Fokker-Planck were studied employing the algebraic approach. The detailed-balance relation was satisfied by Bloch-Redfield theory while the Fokker-planck equations satisfied only the second moments in phase-space of the detailed-balance relation. The generalized Fokker-Planck equation maintaining the general positivity of the reduced density operator considers the T1-relaxation as well as the pure T2 dephasing.