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Quantum state discrimination is a fundamental concept in quantum information theory, which refers to a class of techniques to identify a specific quantum state through a positive operator-valued measure. In this work, we investigate how…

Quantum Physics · Physics 2025-07-09 Hyunho Cha , Jungwoo Lee

We present an optimal quantum algorithm for fidelity estimation between two quantum states when one of them is pure. In particular, the (square root) fidelity of a mixed state to a pure state can be estimated to within additive error…

Quantum Physics · Physics 2025-10-03 Wang Fang , Qisheng Wang

Gate-model quantum computers can allow quantum computations in near-term implementations. The stabilization of an optimal quantum state of a quantum computer is a challenge, since it requires stable quantum evolutions via a precise…

Quantum Physics · Physics 2019-09-04 Laszlo Gyongyosi , Sandor Imre

Quantum state tomography is the problem of estimating a given quantum state. Usually, it is required to run the quantum experiment - state preparation, state evolution, measurement - several times to be able to estimate the output quantum…

General Physics · Physics 2025-04-30 Shibdas Roy , Filippo Caruso , Srushti Patil , Anumita Mukhopadhyay

We investigate the optimal estimation of quantum expectation value of a physical observable, which minimizes a mean error with respect to general measure of deviation, when a finite number of copies of a pure state are prepared. If pure…

Quantum Physics · Physics 2007-05-23 Minoru Horibe , Akihisa Hayashi , Takaaki Hashimoto

Quantum state tomography (QST) represents an essential tool for the characterization, verification, and validation (QCVV) of quantum processors. Only for a few idealized scenarios, there are analytic results for the optimal measurement set…

Quantum Physics · Physics 2022-12-27 Violeta N. Ivanova-Rohling , Niklas Rohling , Guido Burkard

We introduce an operational and statistically meaningful measure, the quantum tomographic transfer function, that possesses important physical invariance properties for judging whether a given informationally complete quantum measurement…

Quantum Physics · Physics 2019-07-31 Jaroslav Rehacek , Yong Siah Teo , Zdenek Hradil

New algorithm for quantum state estimation based on the maximum likelihood estimation is proposed. Existing techniques for state reconstruction based on the inversion of measured data are shown to be overestimated since they do not…

Quantum Physics · Physics 2009-10-30 Zdenek Hradil

Quantum noise constitutes a fundamental obstacle to realizing practical quantum technologies. To address the pivotal challenge of identifying quantum systems least affected by noise, we introduce the purest quantum state identification,…

Quantum Physics · Physics 2025-09-24 Yingqi Yu , Honglin Chen , Jun Wu , Wei Xie , Xiangyang Li

Quantum tomography is a fundamental technique for characterizing, benchmarking, and verifying quantum states and devices. It plays a crucial role in advancing quantum technologies and deepening our understanding of quantum mechanics.…

Robust, accurate and efficient quantum tomography is key for future quantum technologies. Traditional methods are impractical for even medium sized systems and are not robust against noise and errors. Here we report on an experimental…

Quantum Physics · Physics 2016-07-27 Robert J. Chapman , Christopher Ferrie , Alberto Peruzzo

Quantum state tomography is an elementary tool to fully characterize an unknown quantum state. As the quantum hardware scales up in size, the standard quantum state tomography becomes increasingly challenging due to its exponentially…

Quantum Physics · Physics 2022-12-12 Lu Zhong , Chu Guo , Xiaoting Wang

The performance of the quantum approximate optimization algorithm is evaluated by using three different measures: the probability of finding the ground state, the energy expectation value, and a ratio closely related to the approximation…

Quantum Physics · Physics 2020-06-08 Madita Willsch , Dennis Willsch , Fengping Jin , Hans De Raedt , Kristel Michielsen

A simple yet efficient method of linear regression estimation (LRE) is presented for quantum state tomography. In this method, quantum state reconstruction is converted into a parameter estimation problem of a linear regression model and…

Quantum Physics · Physics 2013-12-18 Bo Qi , Zhibo Hou , Li Li , Daoyi Dong , Guoyong Xiang , Guangcan Guo

The reliable characterization of quantum states as well as any potential noise in various quantum systems is crucial for advancing quantum technologies. In this work we propose the concept of corrupted sensing quantum state tomography which…

Quantum Physics · Physics 2025-05-07 Mengru Ma , Jiangwei Shang

We investigate the optimal convex approximation of the quantum state with respect to a set of available states. By isometric transformation, we have presented the general mathematical model and its solutions together with a triple…

Quantum Physics · Physics 2020-06-17 Xiao-Bin Liang , Bo Li , Liang Huang , Biao-Liang Ye , Shao-Ming Fei , Shi-Xiang Huang

Quantum state estimation is important for various quantum information processes, including quantum communications, computation, and metrology, which require the characterization of quantum states for evaluation and optimization. We present…

Quantum Physics · Physics 2026-04-15 C. Vargas , L. Pereira , A. Delgado

Quantum parameter estimation, the ability to precisely obtain a classical value in a quantum system, is very important to many key quantum technologies. Many of these technologies rely on an optical probe, either coherent or squeezed states…

Quantum Physics · Physics 2015-05-14 Trevor A. Wheatley , Mankei Tsang , Ian R. Petersen , Elanor H. Huntington

Measuring the closest distance between two states is an alternative and significant approach in the resource quantification, which is the core task in the resource theory. Quite limited progress has been made for this approach even in…

Quantum Physics · Physics 2022-03-16 Li-qiang Zhang , Deng-hui Yu , Chang-shui Yu

We introduce the concept of selective quantum state tomography or SQST, a tomographic scheme that enables a user to estimate arbitrary elements of an unknown quantum state using a fixed measurement record. We demonstrate how this may be…

Quantum Physics · Physics 2020-06-12 Joshua Morris , Borivoje Dakić