2023/11/27 by А. С. Трушечкин, Trushechkin, Anton
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Physical sciences #Mathematical Physics (math-ph) #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.2311.16010
openalex publication_date 2023/11/27 · openalex created_date 2023/11/29 · openalex updated_date 2026/07/28
We consider a well-known exactly solvable model of an open quantum system with pure decoherence. The aim of this paper is twofold. Firstly, decoherence is a property of open quantum systems important for both quantum technologies and the fundamental question of quantum-classical transition. It is worthwhile to study how the long-term rate of decoherence depends on the spectral density characterizing the system-bath interaction in this exactly solvable model. Secondly, we address a more general problem of the Markovian embedding of a non-Markovian open system dynamics. It is often assumed that a non-Markovian open quantum system can be embedded into a larger Markovian system. However, we show that such embedding is possible only for the Ohmic spectral densities (for the case of a positive bath temperature) and is impossible for both the sub- and super-Ohmic spectral densities. From the other side, for the Ohmic spectral densities, an asymptotic large-time Markovianity (in terms of the quantum regression formula) takes place.