# BubbleProfiler: finding the field profile and action for cosmological phase transitions

## TL;DR

BubbleProfiler is a versatile C++ software tool designed to compute field profiles and bounce actions in cosmological phase transitions involving multiple scalar fields, aiding studies of baryogenesis and gravitational waves.

## Contribution

It introduces a modular, flexible code that implements a perturbative method for multi-field potentials and provides practical tools for analyzing phase transitions in particle physics models.

## Key findings

- Successfully computes bubble profiles and bounce actions in complex models.
- Demonstrates application to the scalar singlet extension of the Standard Model.
- Provides comparisons with existing codes to validate performance.

## Abstract

We present BubbleProfiler, a C++ software package for finding field profiles in bubble walls and calculating the bounce action during phase transitions involving multiple scalar fields. Our code uses a recently proposed perturbative method for potentials with multiple fields and a shooting method for single field cases. BubbleProfiler is constructed with modularity, flexibility and practicality in mind. These principles extend from the input of an arbitrary potential with multiple scalar fields in various forms, through the code structure, to the testing suite. After reviewing the physics context, we describe how the methods are implemented in BubbleProfiler, provide an overview of the code structure and detail usage scenarios. We present a number of examples that serve as test cases of BubbleProfiler and comparisons to existing public codes with similar functionality. We also show a physics application of BubbleProfiler in the scalar singlet extension of the Standard Model of particle physics by calculating the action as a function of model parameters during the electroweak phase transition. BubbleProfiler completes an important link in the toolchain for studying the properties of the thermal phase transition driving baryogenesis and properties of gravitational waves in models with multiple scalar fields. The code can be obtained from: https://github.com/bubbleprofiler/bubbleprofiler