Simultaneous estimations of quantum state and detector through multiple quantum processes

Fuente: arXiv
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Autori principali: Xiao, Shuixin, Liang, Weichao, Wang, Yuanlong, Dong, Daoyi, Petersen, Ian R., Ugrinovskii, Valery
Natura: Preprint
Pubblicazione: 2025
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author Xiao, Shuixin
Liang, Weichao
Wang, Yuanlong
Dong, Daoyi
Petersen, Ian R.
Ugrinovskii, Valery
author_facet Xiao, Shuixin
Liang, Weichao
Wang, Yuanlong
Dong, Daoyi
Petersen, Ian R.
Ugrinovskii, Valery
contents The estimation of all the parameters in an unknown quantum state or measurement device, commonly known as quantum state tomography (QST) and quantum detector tomography (QDT), is crucial for comprehensively characterizing and controlling quantum systems. In this paper, we introduce a framework, in two different bases, that utilizes multiple quantum processes to simultaneously identify a quantum state and a detector. We develop a closed-form algorithm for this purpose and prove that the mean squared error (MSE) scales as $O(1/N) $ for both QST and QDT, where $N $ denotes the total number of state copies. This scaling aligns with established patterns observed in previous works that addressed QST and QDT as independent tasks. Furthermore, we formulate the problem as a sum of squares (SOS) optimization problem with semialgebraic constraints, where the physical constraints of the state and detector are characterized by polynomial equalities and inequalities. The effectiveness of our proposed methods is validated through numerical examples.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11772
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Simultaneous estimations of quantum state and detector through multiple quantum processes
Xiao, Shuixin
Liang, Weichao
Wang, Yuanlong
Dong, Daoyi
Petersen, Ian R.
Ugrinovskii, Valery
Quantum Physics
The estimation of all the parameters in an unknown quantum state or measurement device, commonly known as quantum state tomography (QST) and quantum detector tomography (QDT), is crucial for comprehensively characterizing and controlling quantum systems. In this paper, we introduce a framework, in two different bases, that utilizes multiple quantum processes to simultaneously identify a quantum state and a detector. We develop a closed-form algorithm for this purpose and prove that the mean squared error (MSE) scales as $O(1/N) $ for both QST and QDT, where $N $ denotes the total number of state copies. This scaling aligns with established patterns observed in previous works that addressed QST and QDT as independent tasks. Furthermore, we formulate the problem as a sum of squares (SOS) optimization problem with semialgebraic constraints, where the physical constraints of the state and detector are characterized by polynomial equalities and inequalities. The effectiveness of our proposed methods is validated through numerical examples.
title Simultaneous estimations of quantum state and detector through multiple quantum processes
topic Quantum Physics
url https://arxiv.org/abs/2502.11772