A1 Refereed original research article in a scientific journal
How to design quantum-jump trajectories via distinct master equation representations
Authors: Chruściński Dariusz, Luoma Kimmo, Piilo Jyrki, Smirne Andrea
Publisher: Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften
Publication year: 2022
Journal: Quantum
Journal name in source: Quantum
Article number: 835
Volume: 6
ISSN: 2521-327X
DOI: https://doi.org/10.22331/Q-2022-10-13-835
Web address : https://quantum-journal.org/papers/q-2022-10-13-835/
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/177263332
Preprint address: https://arxiv.org/abs/2009.11312v1
Every open-system dynamics can be associated to infinitely many stochastic pictures, called unravelings, which have proved to be extremely useful in several contexts, both from the conceptual and the practical point of view. Here, focusing on quantum-jump unravelings, we demonstrate that there exists inherent freedom in how to assign the terms of the underlying master equation to the deterministic and jump parts of the stochastic description, which leads to a number of qualitatively different unravelings. As relevant examples, we show that a fixed basis of post-jump states can be selected under some definite conditions, or that the deterministic evolution can be set by a chosen time-independent non-Hermitian Hamiltonian, even in the presence of external driving. Our approach relies on the definition of rate operators, whose positivity equips each unraveling with a continuous-measurement scheme and is related to a long known but so far not widely used property to classify quantum dynamics, known as dissipativity. Starting from formal mathematical concepts, our results allow us to get fundamental insights into open quantum system dynamics and to enrich their numerical simulations.
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