The Faraday Effect as a Two-State Quantum Process

We show that the Faraday effect can be derived from a simple two-state model. This approach uses a quantized electromagnetic field and does not make reference to differences in refractive indices of left- and right-circularly polarized light. Instead it treats the effect as a forward Rayleigh scattering process between two orthogonal modes of the quantized field, and thus emphasises the quantum-mechanical aspects of the phenomenon.