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The uncertainty relation of three quantities in quantum mechanics is estimated in terms of commutators. The Pauli matrices are used to find a contribution of third-order commutators. The resulting inequality refines the Heisenberg…

Quantum Physics · Physics 2025-01-30 Sergei P. Efimov

Sensing and imaging are among the most important applications of quantum information science. To investigate their fundamental limits and the possibility of quantum enhancements, researchers have for decades relied on the quantum…

Quantum Physics · Physics 2016-08-24 Xiao-Ming Lu , Mankei Tsang

An analysis is given of the local phase space of gravity coupled to matter to second order in perturbation theory. Working in local regions with boundaries at finite distance, we identify matter, Coulomb, and additional boundary modes. The…

General Relativity and Quantum Cosmology · Physics 2024-02-09 Viktoria Kabel , Časlav Brukner , Wolfgang Wieland

Uncertainty relations are usually stated as bounds on selected combinations of variances, but the full covariance matrix contains substantially richer information about the geometry of quantum state space and about the operational…

Quantum Physics · Physics 2026-05-13 Dimpi Thakuria , Shuheng Liu , Giuseppe Vitagliano , Konrad Szymański

Quantum measurement and quantum operation theory is developed here by taking the relational properties among quantum systems, instead of the independent properties of a quantum system, as the most fundamental elements. By studying how the…

Quantum Physics · Physics 2021-04-20 Jianhao M. Yang

The generalized uncertainty connection between the fluctuations of a quantum observable and its temporal derivative is derived in this study, we demonstrate that the product of an observable's uncertainties and its time derivative is…

Quantum Physics · Physics 2025-08-26 Tarek Yehia

The uncertainty principle sets limit on our ability to predict the values of two incompatible observables measured on a quantum particle simultaneously. This principle can be stated in various forms. In quantum information theory, it is…

Quantum Physics · Physics 2018-09-27 H. Dolatkhah , S. Haseli , S. Salimi , S. A. Khorashad

In quantum multi-parameter estimation, the precision of estimating unknown parameters is bounded by the Cramer-Rao bound (CRB), defined via the inverse of the Fisher information matrix (FIM). However, in certain scenarios such as…

Quantum Physics · Physics 2025-11-18 Min Namkung , Changhyoup Lee , Hyang-Tag Lim

The concept of quantum coherence, including various ways to quantify the degree of coherence with respect to the prescribed basis, is currently the subject of active research. The complementarity of quantum coherence in different bases was…

Quantum Physics · Physics 2017-09-08 Alexey E. Rastegin

In this paper, I investigate the quantisation of length in euclidean quantum gravity in three dimensions. The starting point is the classical hamiltonian formalism in a cylinder of finite radius. At this finite boundary, a counter term is…

General Relativity and Quantum Cosmology · Physics 2018-04-06 Wolfgang Wieland

We describe a deformation of the observable algebra of quantum gravity in which the loop algebra is extended to framed loops. This allows an alternative nonperturbative quantization which is suitable for describing a phase of quantum…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Seth Major , Lee Smolin

Quantum Fisher information matrix (QFIM) is a core concept in theoretical quantum metrology due to the significant importance of quantum Cram\'{e}r-Rao bound in quantum parameter estimation. However, studies in recent years have revealed…

Quantum Physics · Physics 2020-03-27 Jing Liu , Haidong Yuan , Xiao-Ming Lu , Xiaoguang Wang

By invoking quantum estimation theory we formulate bounds of errors in quantum measurement for arbitrary quantum states and observables in a finite-dimensional Hilbert space. We prove that the measurement errors of two observables satisfy…

Quantum Physics · Physics 2013-05-29 Yu Watanabe , Takahiro Sagawa , Masahito Ueda

Only with the simultaneous estimation of multiple parameters are the quantum aspects of metrology fully revealed. This is due to the incompatibility of observables. The fundamental bound for multi-parameter quantum estimation is the Holevo…

Quantum Physics · Physics 2019-11-20 Francesco Albarelli , Jamie F. Friel , Animesh Datta

The usual concepts of topological physics, such as the Berry curvature, cannot be applied directly to non-Hermitian systems. We show that another object, the quantum metric, which often plays a secondary role in Hermitian systems, becomes a…

Mesoscale and Nanoscale Physics · Physics 2021-03-17 D. D. Solnyshkov , C. Leblanc , L. Bessonart , A. Nalitov , J. Ren , Q. Liao , F. Li , G. Malpuech

In this article we derive a measure of quantumness in quantum multi-parameter estimation problems. We can show that the ratio between the mean Uhlmann Curvature and the Fisher Information provides a figure of merit which estimates the…

Quantum Physics · Physics 2020-01-01 Angelo Carollo , Bernardo Spagnolo , Alexander A. Dubkov , Davide Valenti

Quantum metrology is deeply connected to quantum geometry, through the fundamental notion of quantum Fisher information. Inspired by advances in topological matter, it was recently suggested that the Berry curvature and Chern numbers of…

Quantum Physics · Physics 2024-11-12 Min Yu , Xiangbei Li , Yaoming Chu , Bruno Mera , F. Nur Ünal , Pengcheng Yang , Yu Liu , Nathan Goldman , Jianming Cai

Quantum metrology fundamentally relies upon the efficient management of quantum uncertainties. We show that, under equilibrium conditions, the management of quantum noise becomes extremely flexible around the quantum critical point of a…

Quantum Physics · Physics 2018-07-18 Irénée Frérot , Tommaso Roscilde

Quantum uncertainty relations have deep-rooted significance on the formalism of quantum mechanics. Heisenberg's uncertainty relations attracted a renewed interest for its applications in quantum information science. Robertson derived a…

Quantum Physics · Physics 2023-02-16 Md. Manirul Ali

Measurement is a fundamental notion in the usual approximate quantum mechanics of measured subsystems. Probabilities are predicted for the outcomes of measurements. State vectors evolve unitarily in between measurements and by reduction of…

General Relativity and Quantum Cosmology · Physics 2014-01-14 James B. Hartle