An Inversion Inequality for Potentials in Quantum Mechanics

Abstract

We suppose: (1) that the ground-state eigenvalue E = F(v) of the Schroedinger Hamiltonian H = -Delta + vf(x) in one dimension is known for all values of the coupling v > 0; and (2) that the potential shape can be expressed in the form f(x) = g(x^2), where g is monotone increasing and convex. The inversion inequality f(x) <= fbar(1/(4x^2)) is established, in which the `kinetic potential' fbar(s) is related to the energy function F(v) by the transformation: fbar(s) = F'(v), s = F(v) - vF'(v) As an example f is approximately reconstructed from the energy function F for the potential f(x) = x^2 + 1/(1+x^2).