Role of Quantum Coherence in Kinetic Uncertainty Relations

Fuente: arXiv
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Autores principales: Prech, Kacper, Potts, Patrick P., Landi, Gabriel T.
Formato: Preprint
Publicado: 2024
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author Prech, Kacper
Potts, Patrick P.
Landi, Gabriel T.
author_facet Prech, Kacper
Potts, Patrick P.
Landi, Gabriel T.
contents The Kinetic Uncertainty Relation (KUR) bounds the signal-to-noise ratio of stochastic currents in terms of the number of transitions per unit time, known as the dynamical activity. This bound was derived in a classical context, and can be violated in the quantum regime due to coherent effects. However, the precise connection between KUR violations and quantum coherence has so far remained elusive, despite significant investigation. In this work, we solve this problem by deriving a modified bound that exactly pinpoints how, and when, coherence might lead to KUR violations. Our bound is sensitive to the specific kind of unraveling of the quantum master equation. It therefore allows one to compare quantum jumps and quantum diffusion, and understand, in each case, how quantum coherence affects fluctuations. We illustrate our result on a double quantum dot, where the electron current is monitored either by electron jump detection or with continuous diffusive charge measurement.
format Preprint
id arxiv_https___arxiv_org_abs_2407_14147
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Role of Quantum Coherence in Kinetic Uncertainty Relations
Prech, Kacper
Potts, Patrick P.
Landi, Gabriel T.
Quantum Physics
Mesoscale and Nanoscale Physics
Statistical Mechanics
The Kinetic Uncertainty Relation (KUR) bounds the signal-to-noise ratio of stochastic currents in terms of the number of transitions per unit time, known as the dynamical activity. This bound was derived in a classical context, and can be violated in the quantum regime due to coherent effects. However, the precise connection between KUR violations and quantum coherence has so far remained elusive, despite significant investigation. In this work, we solve this problem by deriving a modified bound that exactly pinpoints how, and when, coherence might lead to KUR violations. Our bound is sensitive to the specific kind of unraveling of the quantum master equation. It therefore allows one to compare quantum jumps and quantum diffusion, and understand, in each case, how quantum coherence affects fluctuations. We illustrate our result on a double quantum dot, where the electron current is monitored either by electron jump detection or with continuous diffusive charge measurement.
title Role of Quantum Coherence in Kinetic Uncertainty Relations
topic Quantum Physics
Mesoscale and Nanoscale Physics
Statistical Mechanics
url https://arxiv.org/abs/2407.14147