1. The problem statement, all variables and given/known data (a) Determine the reflectivity spectrum [tex]R(E)[/tex] of a free particle of mass [tex]m[/tex] reflected from an infinite jump [tex]V(x)[/tex], where [tex]V(x)=0[/tex] if [tex]x\leq0[/tex], [tex]V(x)=-\infty[/tex] if [tex]x>0[/tex] The other similar problem is: (b) Determine the energy levels of a particle of mass [tex]m[/tex] confined to an infinite barrier [tex]U(x)[/tex] of width [tex]L[/tex], where [tex]U(x) = -\infty[/tex] for [tex]x<0, x>L[/tex], [tex]U(x) = 0[/tex] for [tex]0\leq x \leq L[/tex] 2. Relevant equations 3. The attempt at a solution Actually, I can solve these problems. One just solves the Schrodinger equation and matches the boundary conditions at each area. But what I wondered is, how about if we change the problem from a negative potential to a positive potential? (i.e. change the [tex]-\infty[/tex] in the problems to [tex]\infty[/tex]) I think the method to solve the problems are still the same, and the boundary conditions should be the same! So, the solutions would be the same if we change the potential from a bluff to a wall! But intuitively, the bluff and the wall are quite different. Can anyone explain this physically to me? any ideas would be appreciated, thanks!