I just started learning on path integral on my own.
It seems that the path integral method is not always able to be solved, depending on the potential. On the other hand, these potentials are solvable by Schrödinger method (i.e solving the Schrödinger equation).
My question is that which are the potentials that are unsolved yet, and why are these potential important? Is there any place I can read more about them as to why they are unsolvable although there are known solution by Schrödinger method.