  The semiclassical theory of light-matter interactions describes the
interaction between a classical electromagnetic field with a quantum mechanical
two-level system.We show that the quantum mechanical two-level system can be
modeled by a system of two coupled classical harmonic oscillators whose
eigenstates are split in frequency according to the coupling strength and play
the roles of the two levels of the quantum mechanical two-level system. The
effect of the light field on the mechanical system is modeled as a modulation
of the spring constants of the individual oscillators. Using this fully
classical model, we derive the Bloch equations for a two-level system and
discuss the mechanical analogues of Rabi oscillations and coherent control
experiments
