Paper accepted by Quantum Science and Technology!

The paper on quantum state purification has been accepted by Quantum Science and Technology 🎉

Our paper Protocols and trade-offs of quantum state purification by Hongshun Yao, Yu-Ao Chen, Erdong Huang, Kaichu Chen, Honghao Fu and Xin Wang has been accepted by Quantum Science and Technology.

For Quantum Science and Technology: Quantum Science and Technology (QST) is a multidisciplinary, high impact journal devoted to publishing both theoretical and experimental research of the highest quality and significance covering the science and application of all quantum-enabled technologies.

For the paper Protocols and trade-offs of quantum state purification: This work introduces a general state purification framework designed to achieve the highest fidelity with a specified probability and characterize the associated trade-offs. For i.i.d. quantum states under depolarizing noise, our framework can replicate the purification protocol proposed by Barenco et al (1997 SIAM J. Comput. 26 1541–57) and further provide exact formulas for the purification fidelity and probability with explicit trade-offs. We prove the protocols’ optimality for two copies of noisy states with any dimension and confirm its optimality for higher numbers of copies and dimensions through numerical analysis. Our methodological approach paves the way for proving the protocol’s optimality in more general scenarios and leads to optimal protocols for other noise models. Furthermore, we present a systematic implementation method via block encoding and parameterized quantum circuits, providing explicit circuits for purifying three-copy and four-copy states under depolarizing noise. Finally, we estimate the sample complexity and generalize the protocol to a recursive form, demonstrating its practicality for quantum computers with limited memory.