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Related papers: Streaming quantum state purification

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Given multiple copies of a mixed quantum state with an unknown, nondegenerate principal eigenspace, quantum state purification is the task of recovering a quantum state that is closer to the principal eigenstate. A streaming protocol…

Quantum Physics · Physics 2025-03-31 Daniel Grier , Debbie Leung , Zhi Li , Hakop Pashayan , Luke Schaeffer

Quantum state purification is crucial in quantum communication and computation, aiming to recover a purified state from multiple copies of an unknown noisy state. This work introduces a general state purification framework designed to…

Quantum Physics · Physics 2024-09-27 Hongshun Yao , Yu-Ao Chen , Erdong Huang , Kaichu Chen , Honghao Fu , Xin Wang

Quantum error mitigation is essential for computing on the noisy quantum computer with a limited number of qubits. In this paper, we propose a practical protocol of error mitigation by virtually purifying the quantum state without qubit…

Quantum Physics · Physics 2022-03-02 Mingxia Huo , Ying Li

Quantum state purification is the functionality that, given multiple copies of an unknown state, outputs a state with increased purity. This will be an essential building block for near- and middle-term quantum ecosystems before the…

Quantum Physics · Physics 2024-06-14 Bo Yang , Elham Kashefi , Dominik Leichtle , Harold Ollivier

Quantum state purification, a process that aims to recover a state closer to a system's principal eigenstate from multiple copies of an unknown noisy quantum state, is crucial for restoring noisy states to a more useful form in quantum…

Quantum Physics · Physics 2025-09-25 Keming He , Chengkai Zhu , Hongshun Yao , Jinguo Liu , Yinan Li , Xin Wang

Quantum state purification, which operates not by identifying and correcting specific errors but by repeatedly projecting multiple noisy copies onto special subspaces, provides a syndrome-free alternative to quantum error correction.…

Quantum Physics · Physics 2026-04-17 Xing-Chen Guo , Benchi Zhao , Xin Wang

State preparation that initializes quantum systems in a fiducial state and measurements to read outcomes after the evolution of quantum states, both essential elements in quantum information processing in general, may contain noise from…

Quantum Physics · Physics 2024-05-13 Jaemin Kim , Seungchan Seo , Jiyoung Yun , Joonwoo Bae

In this paper we consider the purification of a quantum state using the information obtained from a continuous measurement record, where the classical measurement record is digitized to a single bit per measurement after the measurements…

Quantum Physics · Physics 2012-01-05 Jason F. Ralph , Neil P. Oxtoby

We present a novel procedure to purify quantum states, i.e., purification through Zeno-like measurements. By simply repeating one and the same measurement on a quantum system, one can purify another system in interaction with the former.…

Quantum Physics · Physics 2018-05-01 Kazuya Yuasa , Hiromichi Nakazato , Tomoko Takazawa

Entanglement purification describes a primitive in quantum information processing, where several copies of noisy quantum states are distilled into few copies of nearly-pure states of high quality via local operations and classical…

Quantum Physics · Physics 2024-02-02 Lina Vandré , Otfried Gühne

The precision and sensitivity achievable in quantum metrology are often compromised by the presence of noise. While quantum error correction has emerged as a promising strategy, it is ineffective in addressing noise that is…

Quantum Physics · Physics 2026-05-25 Xiaodie Lin , Linxuan Li , Haidong Yuan

The goal of qubit purification is to combine multiple noisy copies of an unknown pure quantum state to obtain one or more copies that are closer to the pure state. We show that a simple protocol based solely on random SWAP tests achieves…

Quantum Physics · Physics 2025-12-23 Shrigyan Brahmachari , Austin Hulse , Henry D. Pfister , Iman Marvian

Quantum state smoothing is a technique for assigning a valid quantum state to a partially observed dynamical system, using measurement records both prior and posterior to an estimation time. We show that the technique is greatly simplified…

Quantum Physics · Physics 2025-09-09 Kiarn T. Laverick , Areeya Chantasri , Howard M. Wiseman

We introduce the concept of a physical process that purifies a mixed quantum state, taken from a set of states, and investigate the conditions under which such a purification map exists. Here, a purification of a mixed quantum state is a…

Quantum Physics · Physics 2007-05-23 M. Kleinmann , H. Kampermann , T. Meyer , D. Bruss

We consider entanglement purification protocols for multiple copies of qubit states. We use high-dimensional auxiliary entangled systems to learn about number and positions of errors in the noisy ensemble in an explicit and controlled way,…

Quantum Physics · Physics 2021-07-28 Ferran Riera Sàbat , Pavel Sekatski , Alexander Pirker , Wolfgang Dür

To achieve the practical applications of near-term noisy quantum devices, low-cost ways to mitigate the noise damages in the devices are essential. In many applications, the noiseless state we want to prepare is often a pure state, which…

Quantum Physics · Physics 2021-07-16 Zhenyu Cai

Distillation, or purification, is central to the practical use of quantum resources in noisy settings often encountered in quantum communication and computation. Conventionally, distillation requires using some restricted 'free' operations…

Quantum Physics · Physics 2024-04-29 Xiao Yuan , Bartosz Regula , Ryuji Takagi , Mile Gu

We propose a scheme for optimal Gaussian purification of coherent states from several imperfect copies. The proposal is experimentally demonstrated for the case of two copies of a coherent state sent through independent noisy channels. Our…

Quantum Physics · Physics 2009-11-11 Ulrik L. Andersen , Radim Filip , Jaromir Fiurasek , Vincent Josse , Gerd Leuchs

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.…

Quantum Physics · Physics 2026-03-10 Benchi Zhao , Yu-Ao Chen , Xuanqiang Zhao , Chengkai Zhu , Giulio Chiribella , Xin Wang

Suppose you receive a sequence of qubits where each qubit is guaranteed to be in one of two pure states, but you do not know what those states are. Your task is to determine the states. This can be viewed as a kind of quantum state learning…

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