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We derive families of optimal and near-optimal probe states for quantum estimation of the coupling constants of a general two-mode number-conserving bosonic Hamiltonian describing one-body and two-body dynamics. We find that the optimal…

Quantum Physics · Physics 2016-11-23 T. J. Volkoff

We consider time-periodically perturbed 1D Hamiltonian systems possessing one or more separatrices. If the perturbation is weak, then the separatrix chaos is most developed when the perturbation frequency lies in the logarithmically small…

Chaotic Dynamics · Physics 2015-05-13 S. M. Soskin , R. Mannella , O. M. Yevtushenko , I. A. Khovanov , P. V. E. McClintock

Quantum state tomography, aimed at deriving a classical description of an unknown state from measurement data, is a fundamental task in quantum physics. In this work, we analyse the ultimate achievable performance of tomography of…

The formalism of quantum estimation theory is applied to estimate the disorders in the positions of two membranes positioned in a driven cavity. We consider the coupled-cavities and the transmissive-regime models to obtain effective…

Quantum Physics · Physics 2024-06-04 Claudio Sanavio , József Zsolt Bernád , André Xuereb

Multimode Gaussian quantum light, including multimode squeezed and/or multipartite quadrature entangled light, is a very general and powerful quantum resource with promising applications to quantum information processing and metrology…

Quantum Physics · Physics 2010-08-05 Olivier Pinel , Julien Fade , Nicolas Treps , Claude Fabre

We investigate the stabilization of unstable multidimensional partially observed single-sensor and multi-sensor linear systems driven by unbounded noise and controlled over discrete noiseless channels under fixed-rate information…

Optimization and Control · Mathematics 2012-09-21 Andrew P. Johnston , Serdar Yüksel

Critical metrology relies on the precise preparation of a system in its ground state near a quantum phase transition point where quantum correlations get very strong. Typically this increases the quantum Fisher information with respect to…

Quantum Physics · Physics 2024-02-12 Christoph Hotter , Helmut Ritsch , Karol Gietka

We discuss efficient methods to optimize the metrological performance over local Hamiltonians in a bipartite quantum system. For a given quantum state, our methods find the best local Hamiltonian for which the state outperforms separable…

Quantum Physics · Physics 2026-05-25 Árpád Lukács , Róbert Trényi , Tamás Vértesi , Géza Tóth

Variational quantum algorithms are promising applications of noisy intermediate-scale quantum (NISQ) computers. These algorithms consist of a number of separate prepare-and-measure experiments that estimate terms in a Hamiltonian. The…

Quantum Physics · Physics 2020-06-25 Andrew Zhao , Andrew Tranter , William M. Kirby , Shu Fay Ung , Akimasa Miyake , Peter Love

A recently proposed variational quantum algorithm has expanded the horizon of variational quantum computing to nonlinear physics and fluid dynamics. In this work, we probe the ability of such approaches to capture the ground state of the…

Quantum Physics · Physics 2025-07-15 Muhammad Umer , Eleftherios Mastorakis , Sofia Evangelou , Dimitris G. Angelakis

We introduce a method of quantum tomography for a continuous variable system in position and momentum space. We consider a single two-level probe interacting with a quantum harmonic oscillator by means of a class of Hamiltonians, linear in…

Quantum Physics · Physics 2015-03-19 J. Casanova , C. E. Lopez , J. J. Garcia-Ripoll , C. F. Roos , E. Solano

We address phase-shift estimation by means of squeezed vacuum probe and homodyne detection. We analyze Bayesian estimator, which is known to asymptotically saturate the classical Cramer-Rao bound to the variance, and discuss convergence…

Quantum Physics · Physics 2009-11-13 Stefano Olivares , Matteo G. A. Paris

We analyze the scaling of quantum Fisher information with the number of system particles in the limit of large number of particles, as a function of the number of parties interacting with each other, for encoding Hamiltonians having…

Quantum Physics · Physics 2026-02-05 Aparajita Bhattacharyya , Debarupa Saha , Ujjwal Sen

Continuous phase estimation is known to be superior in accuracy as compared to static estimation. The estimation process is, however, desired to be made robust to uncertainties in the underlying parameters. Here, homodyne phase estimation…

Optimization and Control · Mathematics 2015-09-14 Shibdas Roy , Obaid Ur Rehman , Ian R. Petersen , Elanor H. Huntington

Describing the evolution of quantum systems by means of non-Hermitian generators opens a new avenue to explore the dynamical properties naturally emerging in such a picture, e.g. operation at the so-called exceptional points, preservation…

Quantum Physics · Physics 2023-12-01 Javid Naikoo , Ravindra W. Chhajlany , Jan Kolodynski

Quantum metrology enhances the sensitivity of parameter estimation using the distinctive resources of quantum mechanics such as entanglement. It has been shown that the precision of estimating an overall multiplicative factor of a…

Quantum Physics · Physics 2016-05-31 Shengshi Pang , Todd A. Brun

Stability analysis of the Kalman filter under randomly lost measurements has been widely studied. We revisit this problem in a general continuous-time framework, where both the measurement matrix and noise covariance evolve as random…

Systems and Control · Electrical Eng. & Systems 2025-11-19 Xinyi Wang , Devansh R. Agrawal , Dimitra Panagou

Variational algorithms are promising candidates to be implemented on near-term quantum computers. The variational quantum eigensolver (VQE) is a prominent example, where a parametrized trial state of the quantum mechanical wave function is…

Recently we find several candidates of quantum algorithms that may be implementable in near-term devices for estimating the amplitude of a given quantum state, which is a core sub- routine in various computing tasks such as the Monte Carlo…

Quantum Physics · Physics 2021-10-12 Tomoki Tanaka , Yohichi Suzuki , Shumpei Uno , Rudy Raymond , Tamiya Onodera , Naoki Yamamoto

Quantum simulation is a central application of near-term quantum devices, pursued in both analog and digital architectures. A key challenge for both paradigms is the effect of imperfections and noise on predictive power. In this work, we…

Quantum Physics · Physics 2026-05-05 Jayant Rao , Jens Eisert , Tommaso Guaita