Quasi-classical Limit of a Spin Coupled to a Reservoir

A spin (qubit) is in contact with a bosonic reservoir. The state of the reservoir contains a parameter $\varepsilon$ interpolating between quantum and classical reservoir features. We derive the explicit expression for the time-dependent reduced spin density matrix, valid for all values of $\varepsi...

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Main Authors: Michele Correggi, Marco Falconi, Michele Fantechi, Marco Merkli
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2024-12-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2024-12-11-1561/pdf/
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author Michele Correggi
Marco Falconi
Michele Fantechi
Marco Merkli
author_facet Michele Correggi
Marco Falconi
Michele Fantechi
Marco Merkli
author_sort Michele Correggi
collection DOAJ
description A spin (qubit) is in contact with a bosonic reservoir. The state of the reservoir contains a parameter $\varepsilon$ interpolating between quantum and classical reservoir features. We derive the explicit expression for the time-dependent reduced spin density matrix, valid for all values of $\varepsilon$ and for energy conserving interactions. We study decoherence and markovianity properties. Our main finding is that the spin decoherence is enhanced (full decoherence) when the spin is coupled to quantum reservoir states while it is dampened (partial decoherence) when coupled to classical reservoir states. The markovianity properties depend in a subtle way on the classicality parameter $\varepsilon$ and on the finer details of the spin-reservoir interaction. We further examine scattering and periodicity properties for energy exchange interactions.
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institution OA Journals
issn 2521-327X
language English
publishDate 2024-12-01
publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
record_format Article
series Quantum
spelling doaj-art-c83c082d0df3471784cc49690e008af42025-08-20T02:33:47ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2024-12-018156110.22331/q-2024-12-11-156110.22331/q-2024-12-11-1561Quasi-classical Limit of a Spin Coupled to a ReservoirMichele CorreggiMarco FalconiMichele FantechiMarco MerkliA spin (qubit) is in contact with a bosonic reservoir. The state of the reservoir contains a parameter $\varepsilon$ interpolating between quantum and classical reservoir features. We derive the explicit expression for the time-dependent reduced spin density matrix, valid for all values of $\varepsilon$ and for energy conserving interactions. We study decoherence and markovianity properties. Our main finding is that the spin decoherence is enhanced (full decoherence) when the spin is coupled to quantum reservoir states while it is dampened (partial decoherence) when coupled to classical reservoir states. The markovianity properties depend in a subtle way on the classicality parameter $\varepsilon$ and on the finer details of the spin-reservoir interaction. We further examine scattering and periodicity properties for energy exchange interactions.https://quantum-journal.org/papers/q-2024-12-11-1561/pdf/
spellingShingle Michele Correggi
Marco Falconi
Michele Fantechi
Marco Merkli
Quasi-classical Limit of a Spin Coupled to a Reservoir
Quantum
title Quasi-classical Limit of a Spin Coupled to a Reservoir
title_full Quasi-classical Limit of a Spin Coupled to a Reservoir
title_fullStr Quasi-classical Limit of a Spin Coupled to a Reservoir
title_full_unstemmed Quasi-classical Limit of a Spin Coupled to a Reservoir
title_short Quasi-classical Limit of a Spin Coupled to a Reservoir
title_sort quasi classical limit of a spin coupled to a reservoir
url https://quantum-journal.org/papers/q-2024-12-11-1561/pdf/
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AT marcofalconi quasiclassicallimitofaspincoupledtoareservoir
AT michelefantechi quasiclassicallimitofaspincoupledtoareservoir
AT marcomerkli quasiclassicallimitofaspincoupledtoareservoir