Streaming quantum state purification

Quantum state purification is the task of recovering a nearly pure copy of an unknown pure quantum state using multiple noisy copies of the state. This basic task has applications to quantum communication over noisy channels and quantum computation with imperfect devices, but has only been studied p...

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Main Authors: Andrew M. Childs, Honghao Fu, Debbie Leung, Zhi Li, Maris Ozols, Vedang Vyas
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2025-01-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2025-01-21-1603/pdf/
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author Andrew M. Childs
Honghao Fu
Debbie Leung
Zhi Li
Maris Ozols
Vedang Vyas
author_facet Andrew M. Childs
Honghao Fu
Debbie Leung
Zhi Li
Maris Ozols
Vedang Vyas
author_sort Andrew M. Childs
collection DOAJ
description Quantum state purification is the task of recovering a nearly pure copy of an unknown pure quantum state using multiple noisy copies of the state. This basic task has applications to quantum communication over noisy channels and quantum computation with imperfect devices, but has only been studied previously for the case of qubits. We derive an efficient purification procedure based on the swap test for qudits of any dimension, starting with any initial error parameter. Treating the initial error parameter and the dimension as constants, we show that our procedure has sample complexity asymptotically optimal in the final error parameter. Our protocol has a simple recursive structure that can be applied when the states are provided one at a time in a streaming fashion, requiring only a small quantum memory to implement.
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institution Kabale University
issn 2521-327X
language English
publishDate 2025-01-01
publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
record_format Article
series Quantum
spelling doaj-art-f7e130e665d140fa8a35f8c2b0a1f7b82025-01-21T17:01:05ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2025-01-019160310.22331/q-2025-01-21-160310.22331/q-2025-01-21-1603Streaming quantum state purificationAndrew M. ChildsHonghao FuDebbie LeungZhi LiMaris OzolsVedang VyasQuantum state purification is the task of recovering a nearly pure copy of an unknown pure quantum state using multiple noisy copies of the state. This basic task has applications to quantum communication over noisy channels and quantum computation with imperfect devices, but has only been studied previously for the case of qubits. We derive an efficient purification procedure based on the swap test for qudits of any dimension, starting with any initial error parameter. Treating the initial error parameter and the dimension as constants, we show that our procedure has sample complexity asymptotically optimal in the final error parameter. Our protocol has a simple recursive structure that can be applied when the states are provided one at a time in a streaming fashion, requiring only a small quantum memory to implement.https://quantum-journal.org/papers/q-2025-01-21-1603/pdf/
spellingShingle Andrew M. Childs
Honghao Fu
Debbie Leung
Zhi Li
Maris Ozols
Vedang Vyas
Streaming quantum state purification
Quantum
title Streaming quantum state purification
title_full Streaming quantum state purification
title_fullStr Streaming quantum state purification
title_full_unstemmed Streaming quantum state purification
title_short Streaming quantum state purification
title_sort streaming quantum state purification
url https://quantum-journal.org/papers/q-2025-01-21-1603/pdf/
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AT honghaofu streamingquantumstatepurification
AT debbieleung streamingquantumstatepurification
AT zhili streamingquantumstatepurification
AT marisozols streamingquantumstatepurification
AT vedangvyas streamingquantumstatepurification