Symmetries and Thermal Radiation: A Classical Derivation of the Planck Spectrum

TL;DR

This paper presents a classical, relativistic derivation of the Planck spectrum for thermal radiation based on wave fluctuations and zero-point radiation, emphasizing the importance of Lorentz invariance.

Contribution

It offers a novel classical derivation of the Planck spectrum using relativistic wave theory and zero-point fluctuations, contrasting with nonrelativistic approaches.

Findings

Classical zero-point radiation exists only in relativistic theories.

The derivation relies on frame-independent thermal fluctuations.

A Lorentz-covariant classical theory can reproduce the Planck spectrum.

Abstract

A derivation of the Planck spectrum for thermal radiation is given based upon wave fluctuations within relativistic classical physics. The derivation depends crucially on thermal fluctuations existing above the fundamental inertial-frame-independent fluctuations of classical zero-point radiation. Such frame-independent zero-point fluctuations exist only in a relativistic wave theory and cannot exist in a nonrelativistic wave theory. Thus such a classical derivation of the Planck spectrum exists in a Lorentz-covariant classical theory, such as classical electrodynamics, but not in a Galilean-covariant theory where all waves are based upon material media. Classical zero-point radiation provides a purely classical alternative to quanta in the analysis of the Planck spectrum.