The unperturbed Hamiltonian of a two-state system is represented by

There is, in addition, a time-dependent perturbation

(a) At t = 0 the system is known to be in the first state, repre sented by

Using time-dependent perturbation theory and assuming that E⁰₁- E⁰₂  is not close to ±h̄ω, derive an expression for the probability that the system is fo und in the second state represented by

as a function of t(t > 0).

(b) Why is this procedure not valid when

Transcribed Image Text:

0 - (2₂). E Ho=