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We address the problem of policy evaluation in discounted Markov decision processes, and provide instance-dependent guarantees on the $\ell_\infty$-error under a generative model. We establish both asymptotic and non-asymptotic versions of…

Machine Learning · Statistics 2020-03-17 Koulik Khamaru , Ashwin Pananjady , Feng Ruan , Martin J. Wainwright , Michael I. Jordan

One of the main questions of research on quantum many-body systems following unitary out of equilibrium dynamics is to find out how local expectation values equilibrate in time. For non-interacting models, this question is rather well…

Quantum Physics · Physics 2017-04-24 H. Wilming , M. Goihl , C. Krumnow , J. Eisert

Two fast L1 time-stepping methods, including the backward Euler and stabilized semi-implicit schemes, are suggested for the time-fractional Allen-Cahn equation with Caputo's derivative. The time mesh is refined near the initial time to…

Numerical Analysis · Mathematics 2020-12-23 Bingquan Ji , Hong-lin Liao , Luming Zhang

Local solutions for variational and quasi-variational inequalities are usually the best type of solutions that could practically be obtained when in case of lack of convexity or else when available numerical techniques are too limited for…

Optimization and Control · Mathematics 2024-05-16 Didier Aussel , Parin Chaipunya

The imaginary-time evolution of quantum states is integral to various fields, ranging from natural sciences to classical optimization or machine learning. Since simulating quantum imaginary-time evolution generally requires storing an…

Quantum Physics · Physics 2024-01-17 Julien Gacon , Christa Zoufal , Giuseppe Carleo , Stefan Woerner

The variational principle for a thin dust shell in General Relativity is constructed. The principle is compatible with the boundary-value problem of the corresponding Euler-Lagrange equations, and leads to ``natural boundary conditions'' on…

General Relativity and Quantum Cosmology · Physics 2014-11-17 V. D. Gladush

Variational inequalities are a formalism that includes games, minimization, saddle point, and equilibrium problems as special cases. Methods for variational inequalities are therefore universal approaches for many applied tasks, including…

Quantum Annealing (QA) is a computational framework where a quantum system's continuous evolution is used to find the global minimum of an objective function over an unstructured search space. It can be seen as a general metaheuristic for…

Quantum Physics · Physics 2022-02-04 Arthur Braida , Simon Martiel , Ioan Todinca

Variational Inference makes a trade-off between the capacity of the variational family and the tractability of finding an approximate posterior distribution. Instead, Boosting Variational Inference allows practitioners to obtain…

Machine Learning · Computer Science 2021-05-20 Gideon Dresdner , Saurav Shekhar , Fabian Pedregosa , Francesco Locatello , Gunnar Rätsch

We present a formalism that allows for the direct manipulation and optimization of subspaces, circumventing the need to optimize individual states when using subspace methods. Using the determinant state mapping, we can naturally extend…

Quantum Physics · Physics 2026-04-29 Adrien Kahn , Luca Gravina , Filippo Vicentini

This paper is devoted to the distributed continuous-time optimization problem with time-varying objective functions and time-varying nonlinear inequality constraints. Different from most studied distributed optimization problems with…

Optimization and Control · Mathematics 2020-09-08 Shan Sun , Wei Ren

We propose a new variational quantum algorithm, which we refer to as TIMES-ADAPT, that prepares time-evolved states in a low-energy or symmetric subspace of a time-independent Hamiltonian on a quantum computer. Using a specially trained…

Many quantum algorithms have daunting resource requirements when compared to what is available today. To address this discrepancy, a quantum-classical hybrid optimization scheme known as "the quantum variational eigensolver" was developed…

Quantum Physics · Physics 2016-02-05 Jarrod R. McClean , Jonathan Romero , Ryan Babbush , Alán Aspuru-Guzik

The study of many-body quantum dynamics in strongly-correlated systems is extremely challenging. To date few numerical methods exist which are capable of simulating the non-equilibrium dynamics of two-dimensional quantum systems, in part…

Quantum Physics · Physics 2024-09-17 S. J. Thomson , J. Eisert

We present a novel generic framework to approximate the non-equilibrium steady states of dissipative quantum many-body systems. It is based on the variational minimization of a suitable norm of the quantum master equation describing the…

Quantum Physics · Physics 2015-02-20 Hendrik Weimer

This paper derives a new variational equation for the linear least-squares backward error by expressing the backward error in terms of a generalized eigenvalue problem and using results from indefinite linear algebra. For problems with…

Numerical Analysis · Mathematics 2026-05-12 Eric Hallman

Master equations are a useful tool to describe the evolution of open quantum systems. In order to characterize the mathematical features and the physical origin of the dynamics, it is often useful to consider different kinds of master…

Quantum Physics · Physics 2020-08-24 Nina Megier , Andrea Smirne , Bassano Vacchini

An adaptive finite difference scheme for variable-order fractional-time subdiffusion equations in the Caputo form is studied. The fractional time derivative is discretized by the L1 procedure but using nonhomogeneous timesteps. The size of…

Numerical Analysis · Mathematics 2024-09-20 Joaquín Quintana-Murillo , Santos Bravo Yuste

This paper first makes an attempt to investigate the partial information near optimal control of systems governed by forward-backward stochastic differential equations with observation noise under the assumption of a convex control domain.…

Optimization and Control · Mathematics 2017-08-11 Qingxin Meng , Qiuhong Shi , Maoning Tang

Solving the electronic Schrodinger equation for strongly correlated ground states is a long-standing challenge. We present quantum algorithms for the variational optimization of wavefunctions correlated by products of unitary operators,…

Quantum Physics · Physics 2024-08-06 Mario Motta , Kevin J. Sung , James Shee