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Main Authors: Mahadeviya, Khalak, Moreira, Saulo V., Mandal, Sheikh Parvez, Pandit, Mahasweta, Prior, Javier, Mitchison, Mark T.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2510.14926
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author Mahadeviya, Khalak
Moreira, Saulo V.
Mandal, Sheikh Parvez
Pandit, Mahasweta
Prior, Javier
Mitchison, Mark T.
author_facet Mahadeviya, Khalak
Moreira, Saulo V.
Mandal, Sheikh Parvez
Pandit, Mahasweta
Prior, Javier
Mitchison, Mark T.
contents We investigate current fluctuations in open quantum systems beyond the weak-coupling and Markovian regimes, focusing on a coherently driven qubit strongly coupled to a structured bosonic environment. By combining full counting statistics with the reaction coordinate mapping, we develop a framework that enables the calculation of steady-state current fluctuations and their temporal correlations in the strong-coupling regime. Our analysis reveals that, unlike in weak coupling, both the average current and its fluctuations exhibit nonmonotonic dependence on the system-environment interaction strength. Notably, we identify a regime where current noise is suppressed below the classical thermodynamic uncertainty bound, coinciding with enhanced anticorrelations in quantum jump trajectories and faster system relaxation. We further show that these features are linked to nonclassical properties of the reaction coordinate mode, such as non-Gaussianity and quantum coherence. Our results provide new insights and design principles for controlling current fluctuations in quantum devices operating beyond the standard weak-coupling paradigm.
format Preprint
id arxiv_https___arxiv_org_abs_2510_14926
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Current fluctuations in nonequilibrium open quantum systems beyond weak coupling: a reaction coordinate approach
Mahadeviya, Khalak
Moreira, Saulo V.
Mandal, Sheikh Parvez
Pandit, Mahasweta
Prior, Javier
Mitchison, Mark T.
Quantum Physics
We investigate current fluctuations in open quantum systems beyond the weak-coupling and Markovian regimes, focusing on a coherently driven qubit strongly coupled to a structured bosonic environment. By combining full counting statistics with the reaction coordinate mapping, we develop a framework that enables the calculation of steady-state current fluctuations and their temporal correlations in the strong-coupling regime. Our analysis reveals that, unlike in weak coupling, both the average current and its fluctuations exhibit nonmonotonic dependence on the system-environment interaction strength. Notably, we identify a regime where current noise is suppressed below the classical thermodynamic uncertainty bound, coinciding with enhanced anticorrelations in quantum jump trajectories and faster system relaxation. We further show that these features are linked to nonclassical properties of the reaction coordinate mode, such as non-Gaussianity and quantum coherence. Our results provide new insights and design principles for controlling current fluctuations in quantum devices operating beyond the standard weak-coupling paradigm.
title Current fluctuations in nonequilibrium open quantum systems beyond weak coupling: a reaction coordinate approach
topic Quantum Physics
url https://arxiv.org/abs/2510.14926