From Quantum-Mechanical Acceleration Limits to Upper Bounds on Fluctuation Growth of Observables in Unitary Dynamics

Fuente: arXiv
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Auteurs principaux: Cafaro, Carlo, Redjem, Walid, Alsing, Paul M., Bahreyni, Newshaw, Corda, Christian
Format: Preprint
Publié: 2025
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author Cafaro, Carlo
Redjem, Walid
Alsing, Paul M.
Bahreyni, Newshaw
Corda, Christian
author_facet Cafaro, Carlo
Redjem, Walid
Alsing, Paul M.
Bahreyni, Newshaw
Corda, Christian
contents Recently, the notion of a quantum acceleration limit has been proposed for any unitary time evolution of quantum systems governed by arbitrary nonstationary Hamiltonians. This limit articulates that the rate of change over time of the standard deviation of the Hamiltonian operator representing the acceleration of quantum evolution within projective Hilbert space is constrained by the standard deviation of the time-derivative of the Hamiltonian. In this paper, we extend our earlier findings to encompass any observable A within the framework of unitary quantum dynamics, leading to the inequality. This relationship signifies that the speed of the standard deviation of any observable is limited by the standard deviation of its associated velocity-like observable. Finally, for pedagogical purposes, we illustrate the relevance of our inequality by providing clear examples. We choose suitable observables related to the unitary dynamics of two-level quantum systems, as well as a harmonic oscillator within a finite-dimensional Fock space.
format Preprint
id arxiv_https___arxiv_org_abs_2504_00261
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From Quantum-Mechanical Acceleration Limits to Upper Bounds on Fluctuation Growth of Observables in Unitary Dynamics
Cafaro, Carlo
Redjem, Walid
Alsing, Paul M.
Bahreyni, Newshaw
Corda, Christian
Quantum Physics
Recently, the notion of a quantum acceleration limit has been proposed for any unitary time evolution of quantum systems governed by arbitrary nonstationary Hamiltonians. This limit articulates that the rate of change over time of the standard deviation of the Hamiltonian operator representing the acceleration of quantum evolution within projective Hilbert space is constrained by the standard deviation of the time-derivative of the Hamiltonian. In this paper, we extend our earlier findings to encompass any observable A within the framework of unitary quantum dynamics, leading to the inequality. This relationship signifies that the speed of the standard deviation of any observable is limited by the standard deviation of its associated velocity-like observable. Finally, for pedagogical purposes, we illustrate the relevance of our inequality by providing clear examples. We choose suitable observables related to the unitary dynamics of two-level quantum systems, as well as a harmonic oscillator within a finite-dimensional Fock space.
title From Quantum-Mechanical Acceleration Limits to Upper Bounds on Fluctuation Growth of Observables in Unitary Dynamics
topic Quantum Physics
url https://arxiv.org/abs/2504.00261