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arXiv · 2604.11756

Trapped bosons in mean field QED, nonlinear resonance cascades and dynamical BEC formation

Thomas Chen·Ali Mezher
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Abstract

In this paper, we study a system of bosons trapped in a confining potential, interacting with a quantized field of coherent photons in the mean field description of non-relativistic Quantum Electrodynamics (QED) obtained by [N. Leopold and P. Pickl , 2017]. We derive the effective nonlinear cascade equations governing the emission and absorption of coherent photons by the boson subsystem in a combined weak-coupling and macroscopic time limit. We demonstrate that solutions to this nonlinear cascade determine a monotone decreasing energy flow in the boson subsystem, and thereby describe the dynamical formation of a Bose-Einstein condensate (BEC) with full ground state occupation, under conservation of the total boson $L^2$ mass. We note that this process is crucially different from thermal relaxation to the ground state, and fundamentally depends on the nonlinear nature of the cascade dynamics.

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Thomas Chen, Ali Mezher. 2026-04-13. Trapped bosons in mean field QED, nonlinear resonance cascades and dynamical BEC formation. https://arxiv.org/abs/2604.11756

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