Coherent Stimulated Radiation, Coherent Spontaneous Radiation and Coupled Photon Pairs in Non-Uniform Thermally Excited Gaseous Media: Calculation Procedure

Abstract

This work continues the author’s study of the processes of interaction between a quantum electromagnetic field and a spatially non-uniform gaseous medium [1, 5]. Previously unknown optical effects caused by consideration of high-order quantum correlators were discovered. This is caused by the problem of calculation of high-order photonic correlators starting from the fourth order, which appears when the interaction between the quantum electromagnetic field is described using the Feynman diagrams, According to T.A. Matsubara’s technique applied nowadays, these correlators are just neglected. The author’s articles [1, 5] describe the calculation method allowing us to avoid thiscomplication. The method is based on the following. High-order quantum correlators appear when multi-particle problems are studied. If the number of particles is small (hydrogen atom), the problem disappears. Therefore, if we replace a multi-particle problem with a single-particle problem (even if this particle is rather complex), the problem will be solved. Such solution (by using the Γ-operators technique) is described in the said author’s articles. While the standard secondary quantisation technique uses operators of creation and destruction of separate particles, the Γ-operators technique deals with operators of creation and destruction of photon conglomerates (systems). It turns out that high-order correlators just do not appear when the Γ-operators technique is used. This article demonstrates a specific example of application of the Γ-technique.