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arXiv · 0907.4485

Double Well Potential: Perturbation Theory, Tunneling, WKB (beyond instantons)

Alexander V Turbiner
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Abstract

A simple approximate solution for the quantum-mechanical quartic oscillator $V= m^2 x^2+g x^4$ in the double-well regime $m^2<0$ at arbitrary $g \geq 0$ is presented. It is based on a combining of perturbation theory near true minima of the potential, semi-classical approximation at large distances and a description of tunneling under the barrier. It provides 9-10 significant digits in energies and gives for wavefunctions the relative deviation in real $x$-space less than $\lesssim 10^{-3}$.

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Alexander V Turbiner. 2009-07-26. Double Well Potential: Perturbation Theory, Tunneling, WKB (beyond instantons). https://doi.org/10.1142/s0217751x10048937

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