1993/12/07 by J. R. Anglin, Anglin, J. R.
Computer Science · Physics and Astronomy · #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Quantum Electrodynamics and Casimir Effect #Quantum Information and Cryptography #Strong Light-Matter Interactions
paper · pdf · doi:10.48550/arxiv.hep-th/9312046
openalex publication_date 1993/12/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Feynman-Vernon formalism is used to obtain a microscopic, quantum mechanical derivation of black body radiation, for a massless scalar field in 1+1 dimensions, weakly coupled to an environment of finite size. The model exhibits the absorption, thermal equilibrium, and emission properties of a canonical black body, but shows that the thermal radiation propagates outwards from the body, with the Planckian spectrum applying inside a wavefront region of finite thickness. The black body environment used in the derivation can be considered to represent a very fine, granular medium, such as lampblack. In the course of developing the model for black body radiation, thermalization of a single harmonic oscillator by a heat bath with slowly varying spectral density is demonstrated. Bargmann-Fock coherent state variables, being convenient for problems involving harmonic oscillators and free fields, are reviewed and then used throughout the paper. An appendix reviews the justification for using baths of independent harmonic oscillators to model generic quantum environments.