Unified formalism and adaptive algorithms for optimal quantum state, detector and process tomography

Fuente: arXiv
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Autores principales: Xiao, Shuixin, Wang, Xiangyu, Wang, Yuanlong, Hou, Zhibo, Zhang, Jun, Petersen, Ian R., Yan, Wen-Zhe, Yonezawa, Hidehiro, Nori, Franco, Xiang, Guo-Yong, Dong, Daoyi
Formato: Preprint
Publicado: 2025
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author Xiao, Shuixin
Wang, Xiangyu
Wang, Yuanlong
Hou, Zhibo
Zhang, Jun
Petersen, Ian R.
Yan, Wen-Zhe
Yonezawa, Hidehiro
Nori, Franco
Xiang, Guo-Yong
Dong, Daoyi
author_facet Xiao, Shuixin
Wang, Xiangyu
Wang, Yuanlong
Hou, Zhibo
Zhang, Jun
Petersen, Ian R.
Yan, Wen-Zhe
Yonezawa, Hidehiro
Nori, Franco
Xiang, Guo-Yong
Dong, Daoyi
contents Quantum tomography is a standard technique for characterizing, benchmarking and verifying quantum systems/devices and plays a vital role in advancing quantum technology and understanding the foundations of quantum mechanics. Achieving the highest possible tomography accuracy remains a central challenge. Here we unify the infidelity metrics for quantum state, detector and process tomography in a single index $1-F(\hat S,S)$, where $S$ represents the true density matrix, POVM element, or process matrix, and $\hat S$ is its estimator. We establish a sufficient and necessary condition for any tomography protocol to attain the optimal scaling $1-F= O(1/N) $ where $N$ is the number of state copies consumed, in contrast to the $O(1/\sqrt{N})$ worst-case scaling of static methods. Guided by this result, we propose adaptive algorithms with provably optimal infidelity scalings for state, detector, and process tomography. Numerical simulations and quantum optical experiments validate the proposed methods, with our experiments reaching, for the first time, the optimal infidelity scaling in ancilla-assisted process tomography.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05988
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unified formalism and adaptive algorithms for optimal quantum state, detector and process tomography
Xiao, Shuixin
Wang, Xiangyu
Wang, Yuanlong
Hou, Zhibo
Zhang, Jun
Petersen, Ian R.
Yan, Wen-Zhe
Yonezawa, Hidehiro
Nori, Franco
Xiang, Guo-Yong
Dong, Daoyi
Quantum Physics
Quantum tomography is a standard technique for characterizing, benchmarking and verifying quantum systems/devices and plays a vital role in advancing quantum technology and understanding the foundations of quantum mechanics. Achieving the highest possible tomography accuracy remains a central challenge. Here we unify the infidelity metrics for quantum state, detector and process tomography in a single index $1-F(\hat S,S)$, where $S$ represents the true density matrix, POVM element, or process matrix, and $\hat S$ is its estimator. We establish a sufficient and necessary condition for any tomography protocol to attain the optimal scaling $1-F= O(1/N) $ where $N$ is the number of state copies consumed, in contrast to the $O(1/\sqrt{N})$ worst-case scaling of static methods. Guided by this result, we propose adaptive algorithms with provably optimal infidelity scalings for state, detector, and process tomography. Numerical simulations and quantum optical experiments validate the proposed methods, with our experiments reaching, for the first time, the optimal infidelity scaling in ancilla-assisted process tomography.
title Unified formalism and adaptive algorithms for optimal quantum state, detector and process tomography
topic Quantum Physics
url https://arxiv.org/abs/2509.05988