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Beyond the Boltzmann equation for weakly coupled quantum fields

High Energy Physics - Theory 2025-09-03 v2 Statistical Mechanics High Energy Physics - Phenomenology Fluid Dynamics

Abstract

We study the kinetic theory of a weakly interacting quantum field. Assuming a state that is close to homogeneous and stationary, we derive a closed kinetic equation for the rate of change of the occupation numbers, perturbatively in the coupling. For a dilute gas, this reproduces the quantum Boltzmann equation, which only accounts for two-to-two scattering processes. Our expression goes beyond this, with terms accounting for multi-particle scattering processes, which are higher order in the density.

Keywords

Cite

@article{arxiv.2503.09932,
  title  = {Beyond the Boltzmann equation for weakly coupled quantum fields},
  author = {Xu-Yao Hu and Vladimir Rosenhaus},
  journal= {arXiv preprint arXiv:2503.09932},
  year   = {2025}
}

Comments

19 pages, v2: typos fixed, references added

R2 v1 2026-06-28T22:18:24.588Z