The quantum harmonic oscillator is the quantum-mechanical analog of the classical harmonic oscillator. Because an arbitrary potential can usually be approximated as a harmonic potential at the vicinity of a stable equilibrium point, it is one of the most important model systems in quantum mechanics. Furthermore, it is one of the few quantum-mechanical systems for which an exact, analytical solution is known.
The Hamiltonian of the particle is:
where m is the particle's mass, ω is the angular frequency of the oscillator, is the position operator (given by x), and is the momentum operator, given by The first term in the Hamiltonian represents the possible kinetic energy states of the particle, and the second term represents its corresponding possible potential energy states.