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Main Authors: Shukla, Kunal, Chatterjee, Riddhi, Chandrashekar, C. M.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.09477
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author Shukla, Kunal
Chatterjee, Riddhi
Chandrashekar, C. M.
author_facet Shukla, Kunal
Chatterjee, Riddhi
Chandrashekar, C. M.
contents Restart is a common strategy observed in nature that accelerates first-passage processes and has been extensively studied using classical random walks. In the quantum regime, restart in continuous-time quantum walks (CTQWs) has been shown to expedite the quantum hitting times. Here, we study how restarting monitored discrete-time quantum walks (DTQWs) affects the quantum hitting times. We show that the restarted DTQWs outperform classical random walks in target searches, benefiting from quantum ballistic propagation, a feature shared with their continuous-time counterparts. Moreover, the explicit coin degree of freedom in DTQWs allows them to surpass even CTQWs in target detection without sacrificing any quantum advantage. Additionally, knowledge of the target's parity or position relative to the origin can be leveraged to tailor DTQWs for even faster searches. Our study paves the way for more efficient use of DTQWs in quantum-walk-based search algorithms, simulations and modeling of quantum transport towards targeted sites in complex quantum networks.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09477
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Accelerated first detection in discrete-time quantum walks using sharp restarts
Shukla, Kunal
Chatterjee, Riddhi
Chandrashekar, C. M.
Quantum Physics
Restart is a common strategy observed in nature that accelerates first-passage processes and has been extensively studied using classical random walks. In the quantum regime, restart in continuous-time quantum walks (CTQWs) has been shown to expedite the quantum hitting times. Here, we study how restarting monitored discrete-time quantum walks (DTQWs) affects the quantum hitting times. We show that the restarted DTQWs outperform classical random walks in target searches, benefiting from quantum ballistic propagation, a feature shared with their continuous-time counterparts. Moreover, the explicit coin degree of freedom in DTQWs allows them to surpass even CTQWs in target detection without sacrificing any quantum advantage. Additionally, knowledge of the target's parity or position relative to the origin can be leveraged to tailor DTQWs for even faster searches. Our study paves the way for more efficient use of DTQWs in quantum-walk-based search algorithms, simulations and modeling of quantum transport towards targeted sites in complex quantum networks.
title Accelerated first detection in discrete-time quantum walks using sharp restarts
topic Quantum Physics
url https://arxiv.org/abs/2411.09477