English
Related papers

Related papers: Controlling energy conservation in quantum dynamic…

200 papers

We consider quantum systems with energy constraints relative to a reference Hamiltonian. In general, quantum channels and continuous-time dynamics need not satisfy energy conservation. Physically meaningful channels, however, only introduce…

Quantum Physics · Physics 2025-05-09 Lauritz van Luijk

This paper presents a millisecond-level look-ahead control algorithm for energy storage with constant space complexity and worst-case linear run-time complexity. The algorithm connects the optimal control with the Lagrangian multiplier…

Optimization and Control · Mathematics 2019-12-13 Bolun Xu , Magnus Korpas , Audun Botterud , Francis O'Sullivan

A powerful method for calculating the eigenvalues of a Hamiltonian operator consists of converting the energy eigenvalue equation into a matrix equation by means of an appropriate basis set of functions. The convergence of the method can be…

Quantum Physics · Physics 2007-05-23 Paolo Amore , Alfredo Aranda , Francisco Fernandez , Hugh Jones

We propose a novel formulation for parametric finite element methods to simulate surface diffusion of closed curves, which is also called as the curve diffusion. Several high-order temporal discretizations are proposed based on this new…

Numerical Analysis · Mathematics 2024-08-27 Harald Garcke , Wei Jiang , Chunmei Su , Ganghui Zhang

The time-dependent variational principle using generalized Gaussian trial functions yields a finite dimensional approximation to the full quantum dynamics and is used in many disciplines. It is shown how these 'semi-quantum' dynamics may be…

chao-dyn · Physics 2009-10-22 Arjendu K. Pattanayak , William C. Schieve

The structure of classical electrodynamics based on the variational principle together with causality and space-time homogeneity is analyzed. It is proved that in this case the 4-potentials are defined uniquely. On the other hand, the…

General Physics · Physics 2007-11-20 E. Comay

We consider a classical field theory whose equations of motion follow from the least action principle, but the class of admissible trajectories is restricted by differential equations. The key element of the proposed construction is the…

Mathematical Physics · Physics 2025-08-14 Simon Lyakhovich , Nikita Sinelnikov

The variational quantum eigensolver (or VQE) uses the variational principle to compute the ground state energy of a Hamiltonian, a problem that is central to quantum chemistry and condensed matter physics. Conventional computing methods are…

The following principle of minimum energy may be a powerful substitute to the dynamical perturbation method, when the latter is hard to apply. Fluid elements of self-gravitating barotropic flows, whose vortex lines extend to the boundary of…

Astrophysics · Physics 2007-05-23 Joseph Katz , Shogo Inagaki , Asher Yahalom

The dynamical formulation of the optimal transport can be extended through various choices of the underlying geometry (kinetic energy), and the regularization of density paths (potential energy). These combinations yield different…

Machine Learning · Computer Science 2024-07-04 Kirill Neklyudov , Rob Brekelmans , Alexander Tong , Lazar Atanackovic , Qiang Liu , Alireza Makhzani

Protection of gauge invariance in experimental realizations of lattice gauge theories based on energy-penalty schemes has recently stimulated impressive efforts both theoretically and in setups of quantum synthetic matter. A major challenge…

Quantum Gases · Physics 2022-12-07 Jad C. Halimeh , Haifeng Lang , Philipp Hauke

We consider a stochastic process which is (a) described by a continuous-time Markov chain on only short time-scales and (b) constrained to conserve a number of hidden quantities on long time-scales. We assume that the transition matrix of…

Statistical Mechanics · Physics 2020-10-27 Vitaly Vanchurin

In this paper, we consider Langevin processes with mechanical constraints. The latter are a fundamental tool in molecular dynamics simulation for sampling purposes and for the computation of free energy differences. The results of this…

Statistical Mechanics · Physics 2011-04-19 Tony Lelievre , Mathias Rousset , Gabriel Stoltz

In the Lagrangian field theory, one gets different identities for different stress energy-momentum tensors, e.g., canonical energy-momentum tensors. Moreover, these identities are not conservation laws of the above-mentioned energy-momentum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 G. Sardanashvily

We formulate a Herglotz-type variational principle on a Lie algebroid and derive the corresponding Euler--Lagrange--Herglotz equations for a Lagrangian depending on an additional scalar variable $z$. This provides a geometric framework for…

Mathematical Physics · Physics 2025-12-22 Alexandre Anahory Simoes , Leonardo Colombo

We present in detail the recently derived ab-initio molecular dynamics (AIMD) formalism [Phys. Rev. Lett. 101 096403 (2008)], which due to its numerical properties, is ideal for simulating the dynamics of systems containing thousands of…

Many-body quantum-mechanical stationary states that have real valued wavefunctions are shown to satisfy a classical conservation of energy equation with a kinetic energy function. The terms in the equation depend on the probability…

Atomic Physics · Physics 2021-07-23 James P. Finley

We develop a quantum computing scheme utilizing McLachlan variational principle in a hybrid quantum-classical algorithm to accurately calculate the transition dynamics of a closed quantum system with many excited states subject to a strong…

Quantum Physics · Physics 2022-04-26 Yulun Wang , Predrag S. Krstic

In this paper, we consider the numerical approximations for the fourth order Cahn-Hilliard equation with concentration dependent mobility, and the logarithmic Flory-Huggins potential. One challenge in solving such a diffusive system…

Numerical Analysis · Mathematics 2017-01-26 Xiaofeng Yang , Jia Zhao

We develop a variational approach to simulating the dynamics of open quantum many-body systems using deep autoregressive neural networks. The parameters of a compressed representation of a mixed quantum state are adapted dynamically…

Strongly Correlated Electrons · Physics 2021-12-03 Moritz Reh , Markus Schmitt , Martin Gärttner