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Quantum state tomography is a powerful, but resource-intensive, general solution for numerous quantum information processing tasks. This motivates the design of robust tomography procedures that use relevant resources as sparingly as…

Quantum Physics · Physics 2022-01-17 Fernando G. S. L. Brandão , Richard Kueng , Daniel Stilck França

In this paper we address the problem of estimating the posterior distribution of the static parameters of a continuous time state space model with discrete time observations by an algorithm that combines the Kalman filter and a particle…

Computation · Statistics 2019-05-22 Jian He , Asma Khedher , Peter Spreij

To improve the efficiency of the state tomography strategy via weak value, we have searched the optimal coupling strength between the system and measuring device. For an arbitrary d-dimensional quantum system, the optimal strengths being…

Quantum Physics · Physics 2024-02-23 Xuanmin Zhu , Dezheng Zhang , Runping Gao , Qun wei , Lixia Liu , Zijiang Luo

We present a novel quantum tomographic reconstruction method based on Bayesian inference via the Kalman filter update equations. The method not only yields the maximum likelihood/optimal Bayesian reconstruction, but also a covariance matrix…

Quantum Physics · Physics 2011-05-13 Koenraad M. R. Audenaert , S. Scheel

Quantum computation has been growing rapidly in both theory and experiments. In particular, quantum computing devices with a large number of qubits have been developed by IBM, Google, IonQ, and others. The current quantum computing devices…

Quantum Physics · Physics 2021-02-10 Rishabh Gupta , Rongxin Xia , Raphael D. Levine , Sabre Kais

The estimation of the density matrix of a $k$-level quantum system is studied when the parametrization is given by the real and imaginary part of the entries and they are estimated by independent measurements. It is established that the…

Quantum Physics · Physics 2009-11-13 D. Petz , K. M. Hangos , A. Magyar

In this paper, we address a partition-based distributed state estimation problem for large-scale general nonlinear processes by proposing a Kalman-based approach. First, we formulate a linear full-information estimation design within a…

Systems and Control · Electrical Eng. & Systems 2024-04-11 Xiaojie Li , Adrian Wing-Keung Law , Xunyuan Yin

State estimation is a classical problem in quantum information. In optimization of estimation scheme, to find a lower bound to the error of the estimator is a very important step. So far, all the proposed tractable lower bounds use…

Quantum Physics · Physics 2007-05-23 Yoshiyuki Tsuda , Keiji Matsumoto

We investigate quantum parameter estimation based on linear and Kerr-type nonlinear controls in an open quantum system, and consider the dissipation rate as an unknown parameter. We show that while the precision of parameter estimation is…

Quantum Physics · Physics 2017-12-12 Beili Gong , Wei Cui

Measuring the state of quantum computers is a highly non-trivial task, with implications for virtually all quantum algorithms. We propose a novel scheme where identical copies of a quantum state are measured jointly so that all Pauli…

Quantum Physics · Physics 2025-09-03 Rick P. A. Simon , Zheng Shi , Charlie Nation , Andrew Jena , Luca Dellantonio

This work addresses the problem of state estimation in multivariable dynamic systems with quantized outputs, a common scenario in applications involving low-resolution sensors or communication constraints. A novel method is proposed to…

Systems and Control · Electrical Eng. & Systems 2025-09-10 Angel L. Cedeño , Rodrigo A. González , Boris I. Godoy , Juan C. Agüero

We find a large class of pure and mixed input states with which the phase estimation precision saturates the Cramer-Rao bound under the compound measurements of parity and particle number. We further propose a quantum-phase-estimation…

Quantum Physics · Physics 2019-04-23 Haijun Xing , Libin Fu , Su Yi

Rather than point estimators, states of a quantum system that represent one's best guess for the given data, we consider optimal regions of estimators. As the natural counterpart of the popular maximum-likelihood point estimator, we…

Quantum Physics · Physics 2015-06-15 Jiangwei Shang , Hui Khoon Ng , Arun Sehrawat , Xikun Li , Berthold-Georg Englert

Most quantum processors requires pulse sequences for controlling quantum states. Here, we present an alternative algorithm for computing an optimal pulse sequence in order to perform a specific task, being an implementation of a quantum…

Quantum Physics · Physics 2020-05-27 John P. S. Peterson , Roberto S. Sarthour , Raymond Laflamme

Deterministic discrimination of nonorthogonal states is forbidden by quantum measurement theory. However, if we do not want to succeed all the time, i.e. allow for inconclusive outcomes to occur, then unambiguous discrimination becomes…

Quantum Physics · Physics 2009-11-11 Janos Bergou , Ulrike Herzog , Mark Hillery

Quantum parameter estimation holds significant promise for achieving high precision through the utilization of the most informative measurements. While various lower bounds have been developed to assess the best accuracy for estimates, they…

Quantum Physics · Physics 2024-07-19 Jianchao Zhang , Jun Suzuki

State estimation incorporates the feedback in optimization based advanced process control systems and is very important for the performance of model predictive control. We describe the extended Kalman filter, the unscented Kalman filter,…

Online estimation of electromechanical oscillation parameters provides essential information to prevent system instability and blackout and helps to identify event categories and locations. We formulate the problem as a state space model…

Optimization and Control · Mathematics 2017-06-19 Zhe Yu , Di Shi , Zhiwei Wang , Qibing Zhang , Junhui Huang , Sen Pan

Quantum state estimation (or state tomography) is an indispensable task in quantum information processing. Because full state tomography that determines all elements of the density matrix is computationally demanding, one usually takes the…

Quantum Physics · Physics 2023-09-21 Hiroshi Yano , Naoki Yamamoto

We study an optimized measurement that discriminates two mixed quantum states with maximum confidence for each conclusive result, thereby keeping the overall probability of inconclusive results as small as possible. When the rank of the…

Quantum Physics · Physics 2009-11-13 Ulrike Herzog