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A variational method is studied based on the minimum of energy variance. The method is tested on exactly soluble problems in quantum mechanics, and is shown to be a useful tool whenever the properties of states are more relevant than the…

High Energy Physics - Phenomenology · Physics 2009-01-07 Luca Marotta , Fabio Siringo

The possibility to simulate the properties of many-body open quantum systems with a large number of degrees of freedom is the premise to the solution of several outstanding problems in quantum science and quantum information. The challenge…

Quantum Physics · Physics 2019-07-03 Alexandra Nagy , Vincenzo Savona

We ask whether the Eigenstate Thermalization Hypothesis (ETH) is valid in a strong sense: in the limit of an infinite system, {\it every} eigenstate is thermal. We examine expectation values of few-body operators in highly-excited many-body…

Statistical Mechanics · Physics 2014-11-13 Hyungwon Kim , Tatsuhiko N. Ikeda , David A. Huse

Proposed hybrid algorithms encode a combinatorial cost function into a problem Hamiltonian and optimize its energy by varying over a set of states with low circuit complexity. Classical processing is typically only used for the choice of…

Quantum Physics · Physics 2022-08-25 Libor Caha , Alexander Kliesch , Robert Koenig

Approximate combinatorial optimization is a promising use case for quantum computers. The quantum optimization algorithms often employ a fixed ansatz that evolves an unbiased initial state towards states with better values of the optimand,…

Quantum Physics · Physics 2026-04-30 Phillip C. Lotshaw , Titus Morris , Stuart Hadfield , Ryan Bennink

Based on the view that thermal equilibrium should be characterized through macroscopic observations, we develop a general theory about typicality of thermal equilibrium and the approach to thermal equilibrium in macroscopic quantum systems.…

Statistical Mechanics · Physics 2018-08-02 Hal Tasaki

Imaginary time evolution is a powerful tool for studying quantum systems. While it is possible to simulate with a classical computer, the time and memory requirements generally scale exponentially with the system size. Conversely, quantum…

Quantum Physics · Physics 2019-09-17 Sam McArdle , Tyson Jones , Suguru Endo , Ying Li , Simon Benjamin , Xiao Yuan

We investigate the maximum caliber variational principle as an inference algorithm used to predict dynamical properties of complex nonequilibrium, stationary, statistical systems in the presence of incomplete information. Specifically, we…

Statistical Mechanics · Physics 2016-12-28 Carlo Cafaro , Sean Alan Ali

We consider the problem of state estimation in general state-space models using variational inference. For a generic variational family defined using the same backward decomposition as the actual joint smoothing distribution, we establish…

Methodology · Statistics 2022-06-02 Mathis Chagneux , Élisabeth Gassiat , Pierre Gloaguen , Sylvain Le Corff

In QM/MM indirect free energy simulation, QM/MM corrections can be obtained from integration of partial derivatives of alchemical Hamiltonians or from perturbation-based estimators including free energy perturbation (FEP) and acceptance…

Chemical Physics · Physics 2018-10-05 Xiaohui Wang , Zhaoxi Sun

Quantum computers promise to efficiently solve important problems that are intractable on a conventional computer. For quantum systems, where the dimension of the problem space grows exponentially, finding the eigenvalues of certain…

This manuscript explores a variational quantum formulation for nonlinear elasticity problems arising from hyperelastic material models, targeting near term noisy intermediate scale quantum (NISQ) devices. The approach leverages the…

Quantum Physics · Physics 2026-05-29 Uditnarayan Kouskiya , Caglar Oskay

Algorithmic discrepancy theory seeks efficient algorithms to find those two-colorings of a set that minimize a given measure of coloring imbalance in the set, its {\it discrepancy}. The {\it Euclidean discrepancy} problem and the problem of…

Quantum Physics · Physics 2021-03-17 Jiří Lebl , Asif Shakeel

We present a quantum algorithm to estimate parameters at the quantum metrology limit using deterministic quantum computation with one bit. When the interactions occurring in a quantum system are described by a Hamiltonian $H= \theta H_0$,…

Quantum Physics · Physics 2008-07-03 Rolando D. Somma , Sergio Boixo

Expectation values of physical quantities may accurately be obtained by the evaluation of integrals within Many-Body Quantum mechanics, and these multi-dimensional integrals may be estimated using Monte Carlo methods. In a previous…

Computational Physics · Physics 2009-10-01 J. R. Trail

Variational inference is a popular method for estimating model parameters and conditional distributions in hierarchical and mixed models, which arise frequently in many settings in the health, social, and biological sciences. Variational…

Methodology · Statistics 2019-01-10 Ted Westling , Tyler H. McCormick

Quantum processing units boost entanglement at the level of hardware and enable physical simulations of highly correlated electron states in molecules and intermolecular chemical bonds. The variational quantum eigensolver provides a…

According to the eigenstate thermalization hypothesis (ETH), the eigenstate-to-eigenstate fluctuations of expectation values of local observables should decrease with increasing system size. In approaching the thermodynamic limit - the…

Statistical Mechanics · Physics 2021-04-14 Goran Nakerst , Masudul Haque

Effective utilization of flexible loads for grid services, while satisfying end-user preferences and constraints, requires an accurate estimation of the aggregated predictive flexibility offered by the electrical loads. Virtual battery (VB)…

Systems and Control · Electrical Eng. & Systems 2020-03-20 Indrasis Chakraborty , Sai Pushpak Nandanoori , Soumya Kundu , Karanjit Kalsi

Combinatorial optimization models a vast range of industrial processes aiming at improving their efficiency. In general, solving this type of problem exactly is computationally intractable. Therefore, practitioners rely on heuristic…

Quantum Physics · Physics 2022-02-14 David Amaro , Matthias Rosenkranz , Nathan Fitzpatrick , Koji Hirano , Mattia Fiorentini