Stationary state

Steady state is a term from physics that describes a time-independent state of a system.

In quantum mechanics, it refers to eigenstates of the Hamiltonian, ie solutions of the time independent ( stationary ) Schrödinger equation whose energy eigenvalue of the state e:

These eigenstates are of the form:

And its modulus squared, the crucial physical measurements probability distribution, thus irrespective of the time.