Majorana's approach to nonadiabatic transitions validates the adiabatic-impulse approximation

Abstract

The approach by Ettore Majorana for non-adiabatic transitions between two quasi-crossing levels is revisited. We rederive the transition probability, known as the Landau-Zener-St\"{u}ckelberg-Majorana formula, and introduce Majorana's approach to modern readers. This result typically referred as the Landau-Zener formula, was published by Majorana before Landau, Zener, St\"{u}ckelberg. Moreover, we obtain the full wave function, including its phase, which is important nowadays for quantum control and quantum information. The asymptotic wave function correctly describes dynamics far from the avoided-level crossing, while it has limited accuracy in that region.