Power and limitations of distributed quantum state purification

Fuente: arXiv
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Main Authors: Zhao, Benchi, Chen, Yu-Ao, Zhao, Xuanqiang, Zhu, Chengkai, Chiribella, Giulio, Wang, Xin
Format: Preprint
Published: 2025
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author Zhao, Benchi
Chen, Yu-Ao
Zhao, Xuanqiang
Zhu, Chengkai
Chiribella, Giulio
Wang, Xin
author_facet Zhao, Benchi
Chen, Yu-Ao
Zhao, Xuanqiang
Zhu, Chengkai
Chiribella, Giulio
Wang, Xin
contents Quantum state purification protocols, which mitigate noise by converting multiple copies of noisy quantum states into fewer copies with a lower noise level, have applications in quantum communication and computation with imperfect devices. Here, we systematically study the task of state purification in distributed quantum systems, demanding that purification be achieved by local operations and classical communication (LOCC). We prove that, in the presence of depolarizing noise, no LOCC purification protocol starting from two copies can work blindly for all the states in three important sets: the set of all pure two-qubit states, the set of all two-qubit maximally entangled states, and the Bell basis. In stark contrast, we show that a targeted, single-state purification is always achievable in the presence of depolarizing noise, and we provide an explicit analytical LOCC protocol for every given two-qubit state. For arbitrary finite sets of pure states and arbitrary noise profiles, we develop an optimization-based algorithm that systematically designs LOCC purification protocols, and we demonstrate it through concrete examples. Overall, our results identify both fundamental limitations and practical noise reduction strategies for distributed quantum information processing.
format Preprint
id arxiv_https___arxiv_org_abs_2509_08691
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Power and limitations of distributed quantum state purification
Zhao, Benchi
Chen, Yu-Ao
Zhao, Xuanqiang
Zhu, Chengkai
Chiribella, Giulio
Wang, Xin
Quantum Physics
Quantum state purification protocols, which mitigate noise by converting multiple copies of noisy quantum states into fewer copies with a lower noise level, have applications in quantum communication and computation with imperfect devices. Here, we systematically study the task of state purification in distributed quantum systems, demanding that purification be achieved by local operations and classical communication (LOCC). We prove that, in the presence of depolarizing noise, no LOCC purification protocol starting from two copies can work blindly for all the states in three important sets: the set of all pure two-qubit states, the set of all two-qubit maximally entangled states, and the Bell basis. In stark contrast, we show that a targeted, single-state purification is always achievable in the presence of depolarizing noise, and we provide an explicit analytical LOCC protocol for every given two-qubit state. For arbitrary finite sets of pure states and arbitrary noise profiles, we develop an optimization-based algorithm that systematically designs LOCC purification protocols, and we demonstrate it through concrete examples. Overall, our results identify both fundamental limitations and practical noise reduction strategies for distributed quantum information processing.
title Power and limitations of distributed quantum state purification
topic Quantum Physics
url https://arxiv.org/abs/2509.08691