- #1

- 1,868

- 0

## Main Question or Discussion Point

Hi

The unperturbed energy of the ground state a quantum system is denoted E

If we have that delta V = E' - E

Why is that?

The unperturbed energy of the ground state a quantum system is denoted E

_{0}. Now the perturbed energy of the ground state of the same quantum system is denoted E'.If we have that delta V = E' - E

_{0}<0, then my book says that the perturbation is an attractive force.Why is that?