Control of vertex probability via edge-weight modulation in continuous-time quantum walks

Fuente: arXiv
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Autores principales: Vieira, Rafael, Amorim, Edgard P. M.
Formato: Preprint
Publicado: 2024
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author Vieira, Rafael
Amorim, Edgard P. M.
author_facet Vieira, Rafael
Amorim, Edgard P. M.
contents Continuous-time quantum walks (CTQWs) provide a versatile framework for exploring quantum transport on graphs. In this work, we investigate how the introduction of edge-weight modulation at a single vertex can suppress its occupation probability. We show that when the edges connected to the root vertex are enhanced by a factor $J$, the probability of detecting the walker at this vertex decays as $1/J^2$, provided the initial state has no components on the vertex itself or its nearest neighbors. We derive the full eigenvalue and eigenvector structure of this system, revealing that the suppression arises from the decoupling of two symmetric line subgraphs and the destructive interference of higher-order contributions. The analysis is extended to tree graphs, where we demonstrate the same scaling behavior and identify the role of local graph geometry in controlling vertex probabilities. These results suggest edge-weight modulation as a mechanism for manipulating transport pathways in CTQWs, with potential applications in quantum information transfer and state engineering, and may serve as a probe of decoherence effects in open quantum systems.
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id arxiv_https___arxiv_org_abs_2404_04094
institution arXiv
publishDate 2024
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spellingShingle Control of vertex probability via edge-weight modulation in continuous-time quantum walks
Vieira, Rafael
Amorim, Edgard P. M.
Quantum Physics
Continuous-time quantum walks (CTQWs) provide a versatile framework for exploring quantum transport on graphs. In this work, we investigate how the introduction of edge-weight modulation at a single vertex can suppress its occupation probability. We show that when the edges connected to the root vertex are enhanced by a factor $J$, the probability of detecting the walker at this vertex decays as $1/J^2$, provided the initial state has no components on the vertex itself or its nearest neighbors. We derive the full eigenvalue and eigenvector structure of this system, revealing that the suppression arises from the decoupling of two symmetric line subgraphs and the destructive interference of higher-order contributions. The analysis is extended to tree graphs, where we demonstrate the same scaling behavior and identify the role of local graph geometry in controlling vertex probabilities. These results suggest edge-weight modulation as a mechanism for manipulating transport pathways in CTQWs, with potential applications in quantum information transfer and state engineering, and may serve as a probe of decoherence effects in open quantum systems.
title Control of vertex probability via edge-weight modulation in continuous-time quantum walks
topic Quantum Physics
url https://arxiv.org/abs/2404.04094