Polychronic Tunneling: New Tunneling Processes Experiencing Euclidean and Lorentzian Evolution Simultaneously

TL;DR

This paper introduces a novel quantum tunneling process in gravitational settings where Euclidean and Lorentzian evolutions occur simultaneously, potentially increasing tunneling rates and impacting low-energy physics.

Contribution

It formulates a new tunneling process combining Euclidean and Lorentzian evolutions, expanding the understanding of quantum tunneling in gravity.

Findings

New tunneling process can have higher rates than Coleman-De Luccia bounce.

Process exists even in decoupling gravity regime.

Impacts low-energy phenomenology.

Abstract

We discuss new possible tunneling processes in the presence of gravity. We formulate quantum tunneling using the Wheeler-deWitt canonical quantization and the WKB approximation. The distinctive feature of our formulation is that it accommodates the coexistence of Euclidean and Lorentzian evolution. It opens up a new possibility of quantum tunneling; e.g. a bubble wall itself tunnels the potential barrier pulling the field nearby, where the wall region experiences the Euclidean evolution while the other regions experience the Lorentzian evolution simultaneously. We execute numerical analysis and find that such a process can have a much higher tunneling rate than that of the Coleman-De Luccia bounce. We also find that the new tunneling processes exist even in the decoupling regime of gravity and affect low energy phenomenology.