Simple procedure to compute accurate energy levels of a double-well anharmonic oscillator

Abstract

Accurate eigenvalues of the double-well anharmonic oscillator ($H=p^2-Z^2{x}^2+x^4$) are obtained in all regimes of the coupling constant $Z^2$. Tables of some eigenvalues up to $Z^2\le 100$ are presented. The method is nonperturbative and involves the use of an appropriately scaled harmonic basis.