Quantum tunneling from excited states in the steadyon picture

TL;DR

This paper introduces the steadyon picture for calculating quantum tunneling rates from excited states, demonstrating its consistency with traditional methods and exploring regimes where higher resonances dominate tunneling.

Contribution

It extends the steadyon picture to tunneling from excited states and applies it to resonance states, addressing conceptual questions and validating with numerical studies.

Findings

Steadyon picture reproduces WKB results for tunneling.

Higher resonances can dominate tunneling rates in certain regimes.

Numerical analysis confirms theoretical predictions.

Abstract

Recent developments in the understanding of real-time path integrals led to the development of the ``steadyon picture'' for the semi-classical calculation of quantum tunneling rates. We discuss tunneling out of a generic localized initial state in this picture and present its application for the important example of a resonance state in a one-dimensional point particle potential. We find that the steadyon picture indeed reproduces existing results obtained using the WKB method. Our analysis furthermore demonstrates how applying this picture to physical states naturally addresses open conceptual questions regarding this framework. Finally, we perform a numerical study for a specific potential. We demonstrate in particular the existence of regimes in which the tunneling rate is dominated by higher resonances, rather than the false vacuum, as well as their importance.