Stationary State - Spontaneous Decay

Spontaneous Decay

Spontaneous decay complicates the question of stationary states. For example, according to simple (nonrelativistic) quantum mechanics, the hydrogen atom has many stationary states: 1s, 2s, 2p, and so on, are all stationary states. But in reality, only the ground state 1s is truly "stationary": An electron in a higher energy level will spontaneously emit one or more photons to decay into the ground state. This seems to contradict the idea that stationary states should have unchanging properties.

The explanation is that the Hamiltonian used in nonrelativistic quantum mechanics is only an approximation to the Hamiltonian from quantum field theory. The higher-energy electron states (2s, 2p, 3s, etc.) are stationary states according to the approximate Hamiltonian, but not stationary according to the true Hamiltonian, because of vacuum fluctuations. On the other hand, the 1s state is truly a stationary state, according to both the approximate and the true Hamiltonian.

Read more about this topic:  Stationary State

Famous quotes containing the words spontaneous and/or decay:

    What is saved in the cinema when it achieves art is a spontaneous continuity with all mankind. It is not an art of the princes or the bourgeoisie. It is popular and vagrant. In the sky of the cinema people learn what they might have been and discover what belongs to them apart from their single lives.
    John Berger (b. 1926)

    It has taken me nearly twenty years of studied self-restraint, aided by the natural decay of my faculties, to make myself dull enough to be accepted as a serious person by the British public; and I am not sure that I am not still regarded as a suspicious character in some quarters.
    George Bernard Shaw (1856–1950)