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The dynamics of an electronic two-level system coupled to an electromagnetic field are simulated explicitly for one and three dimensional systems through semiclassical propagation of the Maxwell-Liouville equations. We consider three…

We investigate detailed balance for a quantum system interacting with thermal radiation within mixed quantum-classical theory. For a two-level system coupled to classical radiation fields, three semiclassical methods are benchmarked: (1)…

Chemical Physics · Physics 2019-07-17 Hsing-Ta Chen , Tao E. Li , Abraham Nitzan , Joseph E. Subotnik

We describe in detail a mathematical framework in which statistical ensembles of hybrid classical-quantum systems can be properly described. We show how a maximum entropy principle can be applied to derive the microcanonical ensemble of…

Statistical Mechanics · Physics 2026-03-12 J. L. Alonso , C. Bouthelier-Madre , A. Castro , J. Clemente-Gallardo , J. A. Jover-Galtier

Representation of classical dynamics by unitary transformations has been used to develop unified description of hybrid classical-quantum systems with particular type of interaction, and to formulate abstract systems interpolating between…

Quantum Physics · Physics 2015-06-18 M. Radonjic , D. B. Popovic , S. Prvanovic , N. Buric

We consider the dynamics of interacting quantum and classical systems in the Heisenberg representation. Unlike the usual construction in standard quantum mechanics, mixed quantum-classical systems involve the interplay of unitary operators…

Chemical Physics · Physics 2025-05-26 David Martínez-Crespo , Cesare Tronci

The definition of a consistent evolution equation for statistical hybrid quantum-classical systems is still an open problem. In this paper we analyze the case of Ehrenfest dynamics on systems defined by a probability density and identify…

Quantum Physics · Physics 2023-08-30 J. L. Alonso , C. Bouthelier-Madre , J. Clemente-Gallardo , D. Martínez-Crespo , J. Pomar

Many important quantities in quantum information science, such as entropy and entanglement, are non-linear functions of the density matrix and cannot be expressed as operator observables. Standard open-system approaches evolve only a single…

Quantum Physics · Physics 2025-08-20 Julian Rapp , Radhika H. Joshi , Alwin van Steensel , Yuli V. Nazarov , Mohammad H. Ansari

We consider the interaction dynamics of a classical oscillator and a quantum two-level system for different pure-dephasing Hamiltonians of the type $\widehat{H}(q,p)=H_C(q,p)\boldsymbol{1}+H_I(q,p)\widehat\sigma_z$. This type of systems…

Chemical Physics · Physics 2023-03-15 Giovanni Manfredi , Antoine Rittaud , Cesare Tronci

In this work we generalize and combine Gibbs and von Neumann approaches to build, for the first time, a rigorous definition of entropy for hybrid quantum-classical systems. The resulting function coincides with the two cases above when the…

Chemical Physics · Physics 2020-10-21 J. L. Alonso , C. Bouthelier , A. Castro , J. Clemente-Gallardo , J. A. Jover-Galtier

We study a general bipartite quantum system consisting of a spin interacting with a bosonic field, with the initial state prepared as the product of a spin coherent state and a canonical coherent state. Our goal is to develop a…

Quantum Physics · Physics 2026-01-23 Matheus V. Scherer , Lea F. Santos , Alexandre D. Ribeiro

A long-standing challenge in mixed quantum-classical trajectory simulations is the treatment of entanglement between the classical and quantal degrees of freedom. We present a novel approach which describes the emergence of entangled states…

Chemical Physics · Physics 2024-07-18 Johan E. Runeson , Jeremy O. Richardson

Mixed quantum-classical mechanics descriptions are critical to modeling coupled electron-nuclear dynamics, i.e. non-adiabatic molecular dynamics, relevant to photochemical and photophysical processes. We argue that, for polyatomic…

Chemical Physics · Physics 2018-08-21 Roman Baskov , Alexander White , Dmitry Mozyrsky

Applying the theory of self-adjoint extensions of Hermitian operators to Koopman von Neumann classical mechanics, the most general set of probability distributions is found for which entropy is conserved by Hamiltonian evolution. A new…

Statistical Mechanics · Physics 2019-06-24 Gerard McCaul , Alexander Pechen , Denys I. Bondar

We address the decay in open chaotic quantum systems and calculate semiclassical corrections to the classical exponential decay. We confirm random matrix predictions and, going beyond, calculate Ehrenfest time effects. To support our…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Daniel Waltner , Martha Gutierrez , Arseni Goussev , Klaus Richter

We discuss the evolution of purity in mixed quantum/classical approaches to electronic nonadiabatic dynamics in the context of the Ehrenfest model. As it is impossible to exactly determine initial conditions for a realistic system, we…

Chemical Physics · Physics 2012-09-07 J. L. Alonso , J. Clemente-Gallardo , J. C. Cuchí , P. Echenique , F. Falceto

Constrained Hamiltonian description of the classical limit is utilized in order to derive consistent dynamical equations for hybrid quantum-classical systems. Starting with a compound quantum system in the Hamiltonian formulation conditions…

Quantum Physics · Physics 2012-06-08 M. Radonjic , S. Prvanovic , N. Buric

We consider an arbitrary quantum system coupled non perturbatively to a large arbitrary and fully quantum environment. In [G. Ithier and F. Benaych-Georges, Phys. Rev. A 96, 012108 (2017)] the typicality of the dynamics of such an embedded…

Quantum Physics · Physics 2017-12-20 Grégoire Ithier , Saeed Ascroft , Florent Benaych-Georges

In this work, we consider two spins initially prepared in a product of coherent states and study their entanglement dynamics due to a general interacting Hamiltonian. We adopt an approach that allowed the derivation of a semiclassical…

Quantum Physics · Physics 2021-11-03 Matheus V. Scherer , Alexandre D. Ribeiro

We derive the fundamental equations of an optimal control theory for systems containing both quantum electrons and classical ions. The system is modeled with Ehrenfest dynamics, a non-adiabatic variant of molecular dynamics. The general…

Chemical Physics · Physics 2015-06-16 Alberto Castro , E. K. U. Gross

A recent proposal for mixed dynamics of classical and quantum ensembles is shown, in contrast to other proposals, to satisfy the minimal algebraic requirements proposed by Salcedo for any consistent formulation of such dynamics. Generalised…

Quantum Physics · Physics 2008-10-09 Michael J. W. Hall
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