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Main Authors: Skalkin, Andrei, Unanyan, Razmik, Fleischhauer, Michael
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.10854
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author Skalkin, Andrei
Unanyan, Razmik
Fleischhauer, Michael
author_facet Skalkin, Andrei
Unanyan, Razmik
Fleischhauer, Michael
contents Noise is commonly regarded as an adverse effect disrupting communication and coherent transport processes or limiting their efficiency. However, as has been shown for example for small light-harvesting protein complexes decoherence processes can play a significant role in facilitating transport processes, a phenomenon termed environment-assisted quantum transport (ENAQT). We here study numerically and analytically how dephasing noise improves the efficiency of spin excitation transport in a two dimensional lattice with small homogeneous losses. In particular we investigate the efficiency and time of excitation transfer from a random initial site to a specific target site and show that for system sizes below a characteristic scale it can be substantially enhanced by adding small dephasing noise. We derive approximate analytic expressions for the efficiency which become rather accurate in the two limits of small (coherent regime) and large noise (Zeno regime) and give a very good overall estimate. These analytic expressions provide a quantitative description of ENAQT in spatially extended systems and allow to derive conditions for its existence.
format Preprint
id arxiv_https___arxiv_org_abs_2502_10854
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dephasing enhanced transport of spin excitations in a two dimensional lossy lattice
Skalkin, Andrei
Unanyan, Razmik
Fleischhauer, Michael
Quantum Physics
Other Condensed Matter
Biological Physics
Noise is commonly regarded as an adverse effect disrupting communication and coherent transport processes or limiting their efficiency. However, as has been shown for example for small light-harvesting protein complexes decoherence processes can play a significant role in facilitating transport processes, a phenomenon termed environment-assisted quantum transport (ENAQT). We here study numerically and analytically how dephasing noise improves the efficiency of spin excitation transport in a two dimensional lattice with small homogeneous losses. In particular we investigate the efficiency and time of excitation transfer from a random initial site to a specific target site and show that for system sizes below a characteristic scale it can be substantially enhanced by adding small dephasing noise. We derive approximate analytic expressions for the efficiency which become rather accurate in the two limits of small (coherent regime) and large noise (Zeno regime) and give a very good overall estimate. These analytic expressions provide a quantitative description of ENAQT in spatially extended systems and allow to derive conditions for its existence.
title Dephasing enhanced transport of spin excitations in a two dimensional lossy lattice
topic Quantum Physics
Other Condensed Matter
Biological Physics
url https://arxiv.org/abs/2502.10854