A quantum mechanical oscillator with the Hamiltonian H1=p^2/2m +(m(w1)^2 x^2)/2 is initially prepared in its ground state (zero number of oscillatory quanta). Then the Hamiltonian changes abruptly (almost instantly): H1→H2=p^2/2m +(m(w2)^2 x^2)/2 What is the mean number of oscillatory quanta upon the transformation? My first question is what does oscillatory quanta exactly means? Attempt: Theory of quantum harmonic oscillator, the eigenstate formulas, the energy formulas. The only thing that is zero in ground state is n=0, so does it mean oscillatory quanta implies n quantum number.