Quantum-classical motion of charged particles interacting with scalar fields

TL;DR

This paper derives the classical equations governing charged particles interacting with scalar fields from a quantum model, demonstrating the quantum-to-classical transition and establishing well-posedness of the classical system.

Contribution

It provides a rigorous derivation of classical particle-field dynamics from the quantum Nelson model using Wigner measures, confirming Bohr's correspondence principle.

Findings

Validation of the quantum-to-classical transition via Wigner measures

Global well-posedness of the classical particle-field system

Establishment of effective classical equations from quantum models

Abstract

The goal of this article is to investigate the dynamics of semi-relativistic or non-relativistic charged particles in interaction with a scalar meson field. Our main contribution is the derivation of the classical dynamics of a particle-field system as an effective equation of the quantum microscopic Nelson model, in the classical limit where the value of the Planck constant approaches zero ($\hbar\to 0$). Thus, we prove the validity of Bohr's correspondence principle, that is to establish the transition from quantum to classical dynamics. We use a Wigner measure approach to study such transition. Then, as a consequence of this interplay between classical and quantum dynamics, we establish the global well-posedness of the classical particle-field interacting system, despite the low regularity of the related vector field, which prevents the use of a fixed point argument.