Are electromagnetic waves always quantized? Field quanta, exchange quanta, and the experiments that tell them apart
Jarek Duda
Mainstream physics says yes: the electromagnetic field is a quantum system, and even the vacuum fluctuates. But “quantized” can mean two things. Either the field itself carries quanta in flight, or only matter is quantized, with discreteness appearing in what emitters and absorbers exchange, as in direct-action electrodynamics. We sort the evidence. The photoelectric effect, Compton scattering and spectra need only quantized matter. Antibunching, two-photon interference, squeezing, non-destructive photon counting, vacuum sampling, Bell tests and light-by-light scattering exclude a classical field, but none excludes quantum direct action. Two-photon interference follows from summing over emitter–absorber pairings, a permanent, with no quanta in flight. In its established constructions, direct action reproduces QED only with a complete future absorber, which Hoyle and Narlikar found impossible in open Friedmann models. Where light is never absorbed, the readings therefore differ. A history weight on free-ending photons acts as a photon chemical potential, and the microwave background’s blackbody spectrum bounds it at about 2×10⁻⁴. We classify delocalized radiation and propose tests: directional vacuum sampling toward the night sky, where QED predicts no difference and exchange a loss of half the vacuum term or more; a cavity photon with a sky-facing port; and a positron source between open and blocked directions.
•Oct 12, 2026•0 citations