A particle representing a quantum of light or other electromagnetic radiation. A photon carries energy proportional to the radiation frequency but has zero rest mass.
- ‘The world of the realist is populated by electrons and photons, quarks and gluons.’
- ‘Until now, physicists have only been able to entangle photons, electrons and atoms, using different methods in each case.’
- ‘Tiny particles such as photons or atoms can readily be put into a quantum superposition existing in two different states or places at once.’
- ‘The team has also made progress in using photons to carry quantum information between calcium qubits.’
- ‘A photon has zero rest mass, but it carries energy and momentum.’
Early 20th century: from Greek phōs, phōt- light on the pattern of electron.