Electronphoton

Electronphoton is not a standard term in physics. In most contexts it is used informally to describe either the fundamental interaction between an electron and a photon, or as a shorthand for a hypothetical bound state of an electron with a photon. There is no recognized elementary particle by that name in the standard model.

Quantum electrodynamics provides the correct framework for describing electron–photon interactions. The electron field couples to the quantized electromagnetic field at a vertex, allowing processes in which an electron emits or absorbs a photon, changes energy and momentum, and scatters off photons or charged fields. Attempts to treat an electron and a photon as a single stable bound state are not supported by experimental evidence; photons do not form a stationary bound system with a single electron in vacuum.

Phenomena such as the photoelectric effect, Compton scattering, bremsstrahlung, and electron-positron pair production illustrate how electrons and photons interact. In bound systems and materials, strong light–matter coupling can give rise to quasi-particles such as exciton-polaritons or plasmon-polaritons, which are hybrid light-matter states, but these involve collective excitations and more than a single electron and photon.

Research contexts include cavity quantum electrodynamics and nanophotonics, where strong coupling modifies emission rates and energy spectra; these studies use the language of electron–photon coupling rather than a new particle. The term electronphoton is therefore best understood as ambiguous shorthand rather than a defined entity in particle physics.

See also: quantum electrodynamics, photon, electron, polariton, Compton scattering, photoelectric effect, cavity QED.