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Quantum computing devices require exceptional control of their experimental parameters to prepare quantum states and simulate other quantum systems. Classical optimization procedures used to find such optimal control parameters, have…

Quantum Physics · Physics 2024-06-18 Matthew Duschenes , Juan Carrasquilla , Raymond Laflamme

Perturbation theory in quantum mechanics studies how quantum systems interact with their environmental perturbations. Harmonic perturbation is a rare special case of time-dependent perturbations in which exact analysis exists. Some…

Quantum Physics · Physics 2008-01-01 Jie-Hong R. Jiang , Dah-Wei Chiou , Cheng-En Wu

This paper considers the use of singular perturbation approximations for general linear quantum systems where the system dynamics are described in terms of both annihilation and creation operators. Results that are related to the physical…

Quantum Physics · Physics 2012-08-31 Shanon L. Vuglar , Ian R. Petersen

We investigate the dephasing dynamics of a qubit as an effective mechanism for estimating the temperature of its surrounding environment for different symmetrizes. Our approach is fundamentally quantum, leveraging the qubit's susceptibility…

Quantum Physics · Physics 2025-09-16 Anass Hminat , Abdallah Slaoui , Rachid Ahl Laamara , Mourad Telmini

Quantum Fisher information (QFI) plays a vital role in quantum precision measurement, quantum information, many-body physics, and other domains. Obtaining the QFI from experiment for a quantum state reveals insights such as the limits of…

Quantum Physics · Physics 2024-08-26 Qi Liu

The measurement outcomes of two incompatible observables on a particle can be precisely predicted when it is maximally entangled with a quantum memory, as quantified recently [Nature Phys. 6, 659 (2010)]. We explore the behavior of the…

Quantum Physics · Physics 2012-07-26 Z. Y. Xu , W. L. Yang , M. Feng

The estimation of parameters characterizing dynamical processes is central to science and technology. The estimation error changes with the number N of resources employed in the experiment (which could quantify, for instance, the number of…

Quantum Physics · Physics 2012-01-10 B. M. Escher , R. L. de Matos Filho , L. Davidovich

The exceptional points of non-Hermitian systems, where $n$ different energy eigenstates merge into an identical one, have many intriguing properties that have no counterparts in Hermitian systems. In particular, the $\epsilon^{1/n}$…

Quantum Physics · Physics 2019-09-04 Chong Chen , Liang Jin , Ren-Bao Liu

We develop a new master equation as a unified description of the effects of both quantum noise (system-bath interaction) and classical noise on a system's dynamics, using a two-dimensional series expansion method. When quantum and classical…

Quantum Physics · Physics 2020-04-30 Li Yu

When quantum information is spread over a system through nonclassical correlation, it makes retrieving information by local measurements difficult---making global measurement necessary for optimal parameter estimation. In this paper, we…

Quantum Physics · Physics 2018-07-13 Akira Sone , Quntao Zhuang , Paola Cappellaro

Informationally complete measurements form the foundation of universal quantum state reconstruction, while quantum parameter estimation is based on the local structure of the manifold of quantum states. Here we establish a general link…

Quantum Physics · Physics 2025-12-18 Rakesh Saini , Jukka Kiukas , Daniel Burgarth , Alexei Gilchrist

In a statistical analysis in Particle Physics, nuisance parameters can be introduced to take into account various types of systematic uncertainties. The best estimate of such a parameter is often modeled as a Gaussian distributed variable…

Data Analysis, Statistics and Probability · Physics 2019-02-25 Glen Cowan

Quantum-enhanced parameter estimation has widespread applications in many fields. An important issue is to protect the estimation precision against the noise-induced decoherence. Here we develop a general theoretical framework for improving…

Quantum Physics · Physics 2019-04-03 Yao Ma , Mi Pang , Libo Chen , Wen Yang

Quantum phase estimation is one of the key algorithms in the field of quantum computing, but up until now, only approximate expressions have been derived for the probability of error. We revisit these derivations, and find that by ensuring…

Quantum Physics · Physics 2012-02-13 James M. Chappell , Max A. Lohe , Lorenz von Smekal , Azhar Iqbal , Derek Abbott

We have proved new estimates for the coherent control errors of quantum circuits used in quantum computing. These estimates essentially take into account the commutator properties of the Hamiltonians and are based on the formulas of the…

Quantum Physics · Physics 2023-10-12 Vladyslav Bivziuk , Vitalii Slynko

A major obstacle to attain the fundamental precision limit of the phase estimation in an interferometry is the identification and implementation of the optimal measurement. Here we demonstrate that this can be accomplished by the use of…

Quantum Physics · Physics 2017-05-10 Wei Zhong , Yixiao Huang , Xiaoguang Wang , Shi-Liang Zhu

Quantum-enhanced measurements exploit quantum mechanical effects to provide ultra-precise estimates of physical variables for use in advanced technologies, such as frequency calibration of atomic clocks, gravitational waves detection, and…

Quantum Physics · Physics 2014-07-28 J. Calsamiglia , B. Gendra , R. Munoz-Tapia , E. Bagan

This work unifies the equilibrium and non-equilibrium frameworks of quantum metrology within the context of many-body systems. We investigate dynamic sensing schemes to derive an upper bound on the quantum Fisher information for probe…

Quantum Physics · Physics 2025-12-03 Rui Zhang , Yang Yang , Wenkui Ding , Xiaoguang Wang

How precisely can we estimate cosmological parameters by performing a quantum measurement on a cosmological quantum state? In quantum estimation theory the variance of an unbiased parameter estimator is bounded from below by the inverse of…

General Relativity and Quantum Cosmology · Physics 2017-10-17 Marcello Rotondo , Yasusada Nambu

We present a complex field formulation of the quantum estimation theory that works natively with complex statistics on the dependence of complex parameters. This formulation states new complex versions of the main quantities and results of…

Quantum Physics · Physics 2026-04-15 M. Muñoz , L. Pereira , C. Vargas , S. Niklitschek , A. Delgado