Upper Bounds on Fluctuation Growths of Observables in Open Quantum Systems

Fuente: arXiv
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Main Authors: Bahreyni, Newshaw, Alsing, Paul M., Cafaro, Carlo, Redjem, Walid, Corda, Christian
Format: Preprint
Published: 2025
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author Bahreyni, Newshaw
Alsing, Paul M.
Cafaro, Carlo
Redjem, Walid
Corda, Christian
author_facet Bahreyni, Newshaw
Alsing, Paul M.
Cafaro, Carlo
Redjem, Walid
Corda, Christian
contents The upper bounds for the rate of fluctuation growth of an observable in both open and closed quantum systems have been studied actively recently. In our recent work we showed that the rate of fluctuation growth for an observable in a closed quantum system is upper bounded by the fluctuation of its corresponding velocity-like observable. That bound also indicated a tradeoff between the time derivatives of the mean and the standard deviation. In this paper we will look at open quantum systems in two cases. For the first case we find the generator of evolution for an open system employing both the Taylor expansion and the standard time-ordered evolution via the Dyson series, while in the second case we consider no specific information about the evolution of the system. We then find the rate of fluctuation growth in each case. Comparing the upper bounds for each case and considering the upper bound found for a closed system suggest that including more details by separating the contributions of the system and state dynamics seems to result in looser bounds for the rate of fluctuation growth.
format Preprint
id arxiv_https___arxiv_org_abs_2512_10153
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Upper Bounds on Fluctuation Growths of Observables in Open Quantum Systems
Bahreyni, Newshaw
Alsing, Paul M.
Cafaro, Carlo
Redjem, Walid
Corda, Christian
Quantum Physics
The upper bounds for the rate of fluctuation growth of an observable in both open and closed quantum systems have been studied actively recently. In our recent work we showed that the rate of fluctuation growth for an observable in a closed quantum system is upper bounded by the fluctuation of its corresponding velocity-like observable. That bound also indicated a tradeoff between the time derivatives of the mean and the standard deviation. In this paper we will look at open quantum systems in two cases. For the first case we find the generator of evolution for an open system employing both the Taylor expansion and the standard time-ordered evolution via the Dyson series, while in the second case we consider no specific information about the evolution of the system. We then find the rate of fluctuation growth in each case. Comparing the upper bounds for each case and considering the upper bound found for a closed system suggest that including more details by separating the contributions of the system and state dynamics seems to result in looser bounds for the rate of fluctuation growth.
title Upper Bounds on Fluctuation Growths of Observables in Open Quantum Systems
topic Quantum Physics
url https://arxiv.org/abs/2512.10153