Dual representation of dipole photons

Abstract

The quantum polarization and phase properties of an electric dipole radiation are examined. It is shown that, unlike the classical picture, the quantum description of polarization needs nine independent Stokes operators, forming a representation of SU(3) sub-algebra in the Weyl-Heisenberg algebra of photons. A corresponding Cartan algebra determines the cosine and sine of the radiation phase operators. A new representation of dipole photons is proposed. The generators of the Cartan algebra are diagonal in this representation so that the corresponding number states describe the number of photons with given radiation phase. The eigenstates of the radiation phase are determined. They have a discrete spectrum and natural behaviour in the classical limit. The relation between the radiation phase, operational phases and the Pegg-Barnett approach is discussed.