Here is the same question asked in the google-group. In one day after question was asked there were writen more useful information.
I think my questions can be formulated in shorter way:
1. If state of a system is a superposition of the eigen state, how is defined total energy of the system?
2. Should energy conservation low work for this quantum mechanical energy?
3. If energy conservation low is satisfied, is it...
let us suppose that we have a quantum harmonic oscillator being in the first exciting state. It means that system has some definite energy E_1. Than we change force constant of of the oscillator. As a consequence eigen states and there energy are changed. I think that after this change...
I tried to consider one-dimensional anharmonic (cubic) oscillator in second quantization formalism. And I found that energy difference between the first excited state and the ground state (as well as energy difference between the second excited stated and the the first one) as...