Effective dynamics of qubit networks via phase-covariant quantum ensembles

Fuente: arXiv
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Auteurs principaux: Prudhoe, Sean, Akhouri, Unnati, Chin, Tommy, Shandera, Sarah
Format: Preprint
Publié: 2024
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author Prudhoe, Sean
Akhouri, Unnati
Chin, Tommy
Shandera, Sarah
author_facet Prudhoe, Sean
Akhouri, Unnati
Chin, Tommy
Shandera, Sarah
contents We derive a new constructive procedure to rapidly generate ensembles of phase-covariant dynamical maps that may be associated to the individual spins of a closed quantum system. We do this by first computing the single-spin dynamical maps in small XXZ networks and chains, specialized to the class of initial states that guarantees phase-covariant dynamics for each spin. Since the dynamics in any small, closed system contains oscillatory features associated to the system size, we define an averaging procedure to extract time-homogeneous dynamics. We use the the average map and the set of deviations from the average map in the exactly derived ensembles to motivate the form of distributional functions for map parameters. The distributions then straightforwardly generate arbitrary-sized ensembles of channels, constrained by a few global properties. This procedure can also generate ensembles where individual maps are not phase-covariant although the average map is, corresponding to realizations of disordered, or noisy, Hamiltonians. The construction procedure suggests new ways to realize random families of open-system dynamics, subject to constraints that require the ensemble to approximate a partition of a closed system.
format Preprint
id arxiv_https___arxiv_org_abs_2404_15223
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Effective dynamics of qubit networks via phase-covariant quantum ensembles
Prudhoe, Sean
Akhouri, Unnati
Chin, Tommy
Shandera, Sarah
Quantum Physics
We derive a new constructive procedure to rapidly generate ensembles of phase-covariant dynamical maps that may be associated to the individual spins of a closed quantum system. We do this by first computing the single-spin dynamical maps in small XXZ networks and chains, specialized to the class of initial states that guarantees phase-covariant dynamics for each spin. Since the dynamics in any small, closed system contains oscillatory features associated to the system size, we define an averaging procedure to extract time-homogeneous dynamics. We use the the average map and the set of deviations from the average map in the exactly derived ensembles to motivate the form of distributional functions for map parameters. The distributions then straightforwardly generate arbitrary-sized ensembles of channels, constrained by a few global properties. This procedure can also generate ensembles where individual maps are not phase-covariant although the average map is, corresponding to realizations of disordered, or noisy, Hamiltonians. The construction procedure suggests new ways to realize random families of open-system dynamics, subject to constraints that require the ensemble to approximate a partition of a closed system.
title Effective dynamics of qubit networks via phase-covariant quantum ensembles
topic Quantum Physics
url https://arxiv.org/abs/2404.15223