# Tunneling Without Bounce

## TL;DR

This paper investigates tunneling processes in false vacua where traditional Euclidean bounces do not occur, proposing alternative approaches to understand decay mechanisms involving pseudo-bounces and modified boundary conditions.

## Contribution

It introduces a consistent framework for tunneling without bounce solutions, including pseudo-bounces and a modified tunneling action method, validated across multiple approaches.

## Key findings

- Identification of pseudo-bounces as key configurations in tunneling without bounce
- Validation of pseudo-bounce approach via Minkowski space WKB analysis
- Proposal of a modified tunneling action method with adjusted boundary conditions

## Abstract

The false vacua of some potentials do not decay via Euclidean bounces. This typically happens for tunneling actions with a flat direction (in field configuration space) that is lifted by a perturbation into a sloping valley, pushing the bounce off to infinity. Using three different approaches we find a consistent picture for such decays. In the Euclidean approach the bottom of the action valley consists of a family of pseudo-bounces (field configurations with some key good properties of bounces except extremizing the action). The pseudo-bounce result is validated by minimizing a WKB action in Minkowski space along appropriate paths in configuration space. Finally, the simplest approach uses the tunneling action method proposed recently with a simple modification of boundary conditions.