The Quantum Optical Master Equation is of the same order of approximation as the Redfield Equation

Niklas J. Jung, Francesco Rosati, Gabriel L. Rath, Frank K. Wilhelm, Peter K. Schuhmacher

Published 2025-05-10Version 1

Quantum master equations are widely used to describe the dynamics of open quantum systems. All these different master equations rely on specific approximations that may or may not be justified. Starting from a microscopic model, applying the justified approximations only may not result in the desired Lindblad form preserving positivity. The recently proposed Universal Lindblad Equation is in Lindblad form and still retains the same order of approximation as the Redfield master equation [arXiv:2004.01469]. In this work, we prove that the well-known Quantum Optical Master Equation is also in the same equivalence class of approximations. We furthermore compare the Quantum Optical Master Equation and the Universal Lindblad Equation numerically and show numerical evidence that the Quantum Optical Master Equation yields more accurate results.