Electromagnetic Radiation Under Phase Symmetry Breaking in Quantum Systems

According to classical mechanics, electron acceleration results in electromagnetic radiation while in quantum mechanics radiation is considered to be arising out of a transition of the charged particle from a higher to a lower energy state. A different narrative is presented in quantum field theory, which considers radiation as an outcome of the perturbation of zero point energy of quantum harmonic oscillator which results in a change in density of electrons in a given state. The theoretical disconnect in the phenomenological aspect of radiation in classical and quantum mechanics remains an unresolved theoretical challenge. As a charged particle changes its energy state, its wavefunction undergoes a spatial phase change, hence, we argue that the spatial phase symmetry breaking of the wavefunction is a critical aspect of radiation in quantum mechanics. This is also observed in Josephson junction, where a static voltage induces spatial phase symmetry breaking of current resulting in emission of electromagnetic waves. As temporal symmetry breaking of the magnetic vector potential generates classical radiation and a wave-function of a charged particle can always be associated with a specific magnetic vector potential; the concept of radiation under spatial phase symmetry breaking offers a novel perspective towards unifying the phenomenon of radiation in quantum mechanics and classical electromagnetism.