Radiation properties of a Kerr nonlinear blackbody

Abstract

In a Kerr nonlinear blackbody, bare photons with opposite wave vectors and helicities are bound into pairs and unpaired photons are transformed into a different kind of quasiparticle, the nonpolariton. The nonpolariton system constitutes free thermal radiation in the blackbody. The present paper investigates the radiation properties of a Kerr nonlinear blackbody. We found that the spectral energy density and radiation pressure of a Kerr nonlinear blackbody are larger than those of a normal blackbody and that these two quantities are monotonically decreasing functions of the Kerr nonlinear coefficient. Above the transition temperature the photon system is in a normal thermal radiation state, but below the transition temperature it is in a squeezed thermal radiation state. In the transition from the normal to the squeezed thermal radiation state, the phase symmetry of the photon system is spontaneously broken.