Classical-field description of the quantum effects in the light-atom interaction Sergey A. Rashkovskiy Institute for Problems in Mechanics of the Russian Academy of Sciences, Vernadskogo Ave., 101/1, Moscow, 119526, Russia Tomsk State University, 36 Lenina Avenue, Tomsk, 634050, Russia E-mail:
[email protected], Tel. +7 906 0318854 March 1, 2016 Abstract In this paper I show that light-atom interaction can be described using purely classical field theory without any quantization. In particular, atom excitation by light that accounts for damping due to spontaneous emission is fully described in the framework of classical field theory. I show that three well-known laws of the photoelectric effect can also be derived and that all of its basic properties can be described within classical field theory. Keywords Hydrogen atom, classical field theory, light-atom interaction, photoelectric effect, deterministic process, nonlinear Schrödinger equation, statistical interpretation. Mathematics Subject Classification 82C10 1 Introduction The atom-field interaction is one of the most fundamental problems of quantum optics. It is believed that a complete description of the light-atom interaction is possible only within the framework of quantum electrodynamics (QED), when not only the states of an atom are quantized but also the radiation itself. In quantum mechanics, this viewpoint fully applies to iconic phenomena, such as the photoelectric effect, which cannot be explained in terms of classical mechanics and classical electrodynamics according to the prevailing considerations. There were attempts to build a so-called semiclassical theory in which only the states of an atom are quantized while the radiation is considered to be a classical Maxwell field [1-6].