2022/11/20 by Masaaki Tokieda, Cyril Elouard, Tokieda, Masaaki +5
Physics and Astronomy · #FOS: Physical sciences #Quantum Physics (quant-ph) #Quantum and electron transport phenomena #Quantum many-body systems #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.2211.11008
openalex publication_date 2022/11/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
When a composite Lindblad system consists of weakly coupled sub-systems with fast and slow timescales, the description of slow dynamics can be simplified by discarding fast degrees of freedom. This model reduction technique is called adiabatic elimination. While second-order perturbative expansion with respect to the timescale separation has revealed that the evolution of a reduced state is completely positive, this paper presents an example exhibiting complete positivity violation in the fourth-order expansion. Despite the non-uniqueness of slow dynamics parametrization, we prove that complete positivity cannot be ensured in any parametrization. The violation stems from correlation in the initial state.