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This paper addresses the regulation and trajectory-tracking problems for two classes of weakly coupled electromechanical systems. To this end, we formulate an energy-based model for these systems within the port-Hamiltonian framework. Then,…

Systems and Control · Electrical Eng. & Systems 2024-07-12 N. Javanmardi , P. Borja , M. J. Yazdanpanah , J. M. A. Scherpen

Unbiased stochastic sampling of the one- and two-body reduced density matrices is achieved in full configuration interaction quantum Monte Carlo with the introduction of a second, "replica" ensemble of walkers, whose population evolves in…

Computational Physics · Physics 2015-09-02 Robert E. Thomas , Daniel Opalka , Catherine Overy , Peter J. Knowles , Ali Alavi , George H. Booth

The Transformer model, renowned for its powerful attention mechanism, has achieved state-of-the-art performance in various artificial intelligence tasks but faces challenges such as high computational cost and memory usage. Researchers are…

Quantum Physics · Physics 2026-03-24 Yuichi Kamata , Quoc Hoan Tran , Yasuhiro Endo , Hirotaka Oshima

The variational quantum eigensolver (VQE) algorithm combines the ability of quantum computers to efficiently compute expectation values with a classical optimization routine in order to approximate ground state energies of quantum systems.…

We analyze the time-resolved energy transport and the entropy production in ac-driven quantum coherent electron systems coupled to multiple reservoirs at finite temperature. At slow driving we formulate the first and second laws of…

Mesoscale and Nanoscale Physics · Physics 2016-07-27 Maria Florencia Ludovico , Michael Moskalets , David Sanchez , Liliana Arrachea

Auxiliary Field Quantum Monte Carlo (AFQMC) has emerged as a powerful framework for treating strongly correlated electronic systems, offering a favorable balance between computational cost and accuracy. In this paper, we present a novel…

Chemical Physics · Physics 2026-04-03 Maxine Luo , Victor Chen , Yu Wang , Christian B. Mendl

Low-energy nuclear fusion reactions have been described using a dynamical coupled-channels density matrix method, based on the theory of open quantum systems. For the first time, this has been combined with an energy projection method,…

Nuclear Theory · Physics 2022-03-01 Iain Lee , Alexis Diaz-Torres

In a recent article [A. Kurcz et al., Phys. Rev. A 81, 063821 (2010)] we predicted an energy concentrating mechanism in composite quantum systems. Its result is a non-zero stationary state photon emission rate even in the absence of…

Quantum Physics · Physics 2015-05-20 Almut Beige , Antonio Capolupo , Andreas Kurcz , Emilio Del Giudice , Giuseppe Vitiello

The study shows that presence of the quantum coherent, unitary component of the evolution of the system can improve constancy of heat engines, i.e., decrease fluctuations of the output power, in comparison with purely stochastic setups.…

Mesoscale and Nanoscale Physics · Physics 2018-08-28 Krzysztof Ptaszynski

In Grossu et al. (2012) we presented a Chaos Many-Body Engine (CMBE) toy-model for chaos analysis of relativistic nuclear collisions at 4.5 A GeV/c (the SKM 200 collaboration) which was later extended to Cu + Cu collisions at the maximum…

Computational Physics · Physics 2019-02-14 I. V. Grossu , C. Besliu , Al. Jipa , D. Felea , E. Stan , T. Esanu

Experiments indicate that collective coupling of molecular ensembles to confined optical modes can modify excited-state dynamics and photochemical reactivity. To describe such cavity-induced effects at atomic resolution, semi-classical…

Chemical Physics · Physics 2026-03-06 Arun Kumar Kanakati , Oriol Vendrell , Gerrit Groenhof

The metriplectic formalism is useful for describing complete dynamical systems which conserve energy and produce entropy. This creates challenges for model reduction, as the elimination of high-frequency information will generally not…

Numerical Analysis · Mathematics 2022-12-28 Anthony Gruber , Max Gunzburger , Lili Ju , Zhu Wang

A pure-dephasing reservoir acting on an individual quantum system induces loss of coherence without energy exchange. When acting on composite quantum systems, dephasing reservoirs can lead to a radically different behavior. Transport of…

Quantum Physics · Physics 2015-02-03 T. Werlang , D. Valente

An accurate description of nonadiabatic dynamics of molecular species on metallic surfaces poses a serious computational challenge associated with a multitude of closely-spaced electronic states. We propose a mixed quantum-classical scheme…

Chemical Physics · Physics 2017-01-10 Ilya G. Ryabinkin , Artur F. Izmaylov

We present a thermodynamically consistent energetic variational model for active nematics driven by ATP hydrolysis, with a focus on the coupling between chemical reactions and mechanical dynamics. Extending the classical Toner-Tu framework,…

Soft Condensed Matter · Physics 2025-07-01 Yiwei Wang

We investigate conservation laws in the quantum mechanics of closed systems. We review an argument showing that exact decoherence implies the exact conservation of quantities that commute with the Hamiltonian including the total energy and…

General Relativity and Quantum Cosmology · Physics 2009-10-22 James B. Hartle , Raymond Laflamme , Donald Marolf

Collective light-matter interactions have been used to control chemistry and energy transfer, yet accessible approaches that combine ab initio methodology with large many-body quantum optical systems are missing due to the fast increase in…

Quantum Physics · Physics 2024-08-27 Frieder Lindel , Dominik Lentrodt , Stefan Yoshi Buhmann , Christian Schäfer

The quantum dynamics of electron-nuclear systems is analyzed from the perspective of the exact factorization of the wavefunction, with the aim of defining gauge invariant equations of motion for both the nuclei and the electrons. For pure…

Chemical Physics · Physics 2023-10-16 Rocco Martinazzo , Irene Burghardt

Electronic coherences are key to understanding and controlling photo-induced molecular transformations. We identify a crucial quantum-mechanical feature of electron-nuclear correlation, the projected nuclear quantum momenta, essential to…

Chemical Physics · Physics 2024-11-13 Evaristo Villaseco Arribas , Neepa T. Maitra

We extend the coupled-cluster method to correlated quantum dynamics of both closed and open systems at finite temperatures using the thermo-field formalism. The approach expresses the time-dependent density matrix in an exponential ansatz…

Quantum Physics · Physics 2019-10-23 Philip Shushkov , Thomas F. Miller