title: When do perturbative approaches accurately capture the dynamics of complex quantum systems?
abstract: Understanding the dynamics of higher-dimensional quantum systems embedded in a complex environment remains a significant theoretical challenge. While several approaches yielding numerically converged solutions exist, these are computationally expensive and often provide only limited physical insight. Here we address the question: when do more intuitive and simpler-to-compute second-order perturbative approaches provide adequate accuracy? We develop a simple analytical criterion and verify its validity for the case of the much-studied FMO dynamics as well as the canonical spin-boson model.
authors.affiliation: Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom.
authors.forename: Amir
authors.initials: A
authors.lastname: Fruchtman
authors.affiliation: CEMS, RIKEN, Saitama, 351-0198, Japan.
authors.forename: Neill
authors.initials: N
authors.lastname: Lambert
authors.affiliation: SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, EH14 4AS, United Kingdom.
authors.forename: Erik M
authors.initials: EM
authors.lastname: Gauger