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Related papers: Adaptive estimation of quantum observables

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Contrary to the assumption that most quantum error-correcting codes (QECC) make, it is expected that phase errors are much more likely than bit errors in physical devices. By employing the entanglement-assisted stabilizer formalism, we…

Quantum Physics · Physics 2011-04-27 Yuichiro Fujiwara , Min-Hsiu Hsieh

The variational quantum eigensolver (VQE) is an algorithm for finding the ground states of a given Hamiltonian. Its application to binary-formulated combinatorial optimization (CO) has been widely studied in recent years. However, typical…

Quantum Physics · Physics 2025-08-08 Ningyi Xie , Xinwei Lee , Tiejin Chen , Yoshiyuki Saito , Nobuyoshi Asai , Dongsheng Cai

We provide a review of the experimental and theoretical research in the field of quantum tomography with an emphasis on recently developed adaptive protocols. Several statistical frameworks for adaptive experimental design are discussed. We…

Quantum Physics · Physics 2016-11-03 Stanislav Straupe

Using the convex structure of positive operator value measurements and of several quantities used in quantum metrology, such as quantum Fisher information or the quantum Van Trees information, we present an efficient numerical method to…

Quantum Physics · Physics 2020-08-11 Esteban Martínez-Vargas , Carlos Pineda , Pablo Barberis-Blostein

Quantum error correction allows for faulty quantum systems to behave in an effectively error free manner. One important class of techniques for quantum error correction is the class of quantum subsystem codes, which are relevant both to…

Quantum Physics · Physics 2013-05-29 Gregory M. Crosswhite , Dave Bacon

Quantum state estimation for continuously monitored dynamical systems involves assigning a quantum state to an individual system at some time, conditioned on the results of continuous observations. The quality of the estimation depends on…

Quantum Physics · Physics 2022-05-26 Areeya Chantasri , Ivonne Guevara , Kiarn T. Laverick , Howard M. Wiseman

An observer-based Hamiltonian identification algorithm for quantum systems is proposed. For the 2-level case an exponential convergence result based on averaging arguments and some relevant transformations is provided. The convergence for…

Mathematical Physics · Physics 2007-05-23 Mazyar Mirrahimi , Pierre Rouchon

Quantum annealing is a generic algorithm using quantum-mechanical fluctuations to search for the solution of an optimization problem. The present paper first reviews the fundamentals of quantum annealing and then reports on preliminary…

Disordered Systems and Neural Networks · Physics 2010-06-10 Masayuki Ohzeki , Hidetoshi Nishimori

We devise powerful algorithms based on differential evolution for adaptive many-particle quantum metrology. Our new approach delivers adaptive quantum metrology policies for feedback control that are orders-of-magnitude more efficient and…

Quantum Physics · Physics 2013-06-04 Neil B. Lovett , Cécile Crosnier , Martí Perarnau-Llobet , Barry C. Sanders

In this work we introduce a general scheme for measurement based quantum computation in continuous variables. Our approach does not necessarily rely on the use of ancillary cluster states to achieve its aim, but rather on the detection of a…

Quantum Physics · Physics 2017-02-01 Giulia Ferrini , Jonathan Roslund , Francesco Arzani , Claude Fabre , Nicolas Treps

Quantum phase estimation is one of the most important tools in quantum algorithms. It can be made non-adaptive (meaning all applications of the unitary $U_\phi$ happen simultaneously) without using more applications of $U_\phi$, albeit at…

Quantum Physics · Physics 2025-11-10 Noah Linden , Ronald de Wolf

Quantum error correction of a surface code or repetition code requires the pairwise matching of error events in a space-time graph of qubit measurements, such that the total weight of the matching is minimized. The input weights follow from…

Quantum Physics · Physics 2018-08-01 S. T. Spitz , B. Tarasinski , C. W. J. Beenakker , T. E. O'Brien

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

Quantum computing is an emerging field on the multidisciplinary interface between physics, engineering, and computer science with the potential to make a large impact on computational intelligence (CI). The aim of this paper is to introduce…

The characterization of collective behavior and nonequilibrium phase transitions in quantum systems is typically rooted in the analysis of suitable system observables, so-called order parameters. These observables might not be known a…

Quantum Physics · Physics 2026-02-20 Erik Fitzner , Francesco Carnazza , Federico Carollo , Igor Lesanovsky

Quantum metrology is supposed to significantly improve the precision of parameter estimation by utilizing suitable quantum resources. However, the predicted precision can be severely distorted by realistic noises. Here, we propose a…

Quantum Physics · Physics 2023-02-15 Yue Zhai , Xiaodong Yang , Kai Tang , Xinyue Long , Xinfang Nie , Tao Xin , Dawei Lu , Jun Li

Reducing the number of measurements required to estimate the expectation value of an observable is crucial for the variational quantum eigensolver to become competitive with state-of-the-art classical algorithms. To measure complicated…

Quantum Physics · Physics 2023-01-09 Seonghoon Choi , Tzu-Ching Yen , Artur F. Izmaylov

We propose a classification of measurement apparatuses based on their reliability and accessibility. Our notion of reliability parameterises the possibility of getting unexpected wrong results when using the apparatus in a given time…

Quantum Physics · Physics 2024-07-26 Nicola Pranzini , Paola Verrucchi

Achieving quantum advantage in efficiently estimating collective properties of quantum many-body systems remains a fundamental goal in quantum computing. While the quantum gradient estimation (QGE) algorithm has been shown to achieve doubly…

Quantum Physics · Physics 2025-05-05 Yuki Koizumi , Kaito Wada , Wataru Mizukami , Nobuyuki Yoshioka

Sampling noisy intermediate-scale quantum devices is a fundamental step that converts coherent quantum-circuit outputs to measurement data for running variational quantum algorithms that utilize gradient and Hessian methods in cost-function…

Quantum Physics · Physics 2023-07-04 Y. S. Teo