AutoTherm: Automated Thermal Field Theory rates for cosmology
Abstract
AutoTherm is a modular code automating the determination of thermal production and interaction rates for cosmology from Thermal Field Theory. This first release computes fully automatically the leading-order contribution from ultrarelativistic 2↔ 2 processes to the production rate of an off-equilibrium ϑ particle coupled to a thermal bath. It takes as input a FeynRules model file describing the Lagrangian of the bath-ϑ system. The AutoTherm program consists of a Wolfram package, which utilises FeynArts/FormCalc, together with a few Python modules for symbolic and numerical routines. Their combined usage leads from the model file to the rate, but each component can also be used in a standalone manner. The main strength of this release is the automated, model-independent handling of Hard Thermal Loop resummation, which is necessary whenever a 2↔ 2 process is mediated by a t-channel massless mediator. Developments in Thermal Field Theory reduce the apparently large model dependence to the determination of the thermal mass of the mediator, which we automate successfully. They further allow us to provide three leading-order-equivalent implementations of HTL resummation. Their spread provides a first estimate of the theory uncertainty from higher-order thermal corrections. We showcase the strength of our AutoTherm framework by successfully reproducing or correcting a host of results in the literature, such as the thermal production rate of ultrarelativistic right-handed neutrinos, of gravitons and gravitinos, of axions and of dark photons.
Related
- Thermal gravitino and axino rate from AutoTherm
- Field-level weak lensing cosmology with $60$ simulations using multifidelity simulation-based inference
- Gravitational Wave Propagation in K-essence Cosmology: Theory and Observational Constraints
- Four-Sector Cosmology (FSC): A Complex Dark Energy Field, Spontaneous Symmetry Breaking, and the Origin of the Cosmological Constant from Observed Matter Asymmetry δ = 0.2%
- Paper CQ-A: The FSC Standard Model: A Complete First-Principles Theory of Cosmology from Z4 x CPT Symmetry
BibTeX
@misc{bouzoud2026autotherm,
title = {{AutoTherm: Automated Thermal Field Theory rates for cosmology}},
author = {Killian Bouzoud and Jacopo Ghiglieri and Greg Jackson},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20936},
eprint = {2609.20936},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05763136v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - AutoTherm: Automated Thermal Field Theory rates for cosmology
AU - Killian Bouzoud
AU - Jacopo Ghiglieri
AU - Greg Jackson
PY - 2026
DA - 2026/09/17
PB - HAL
DO - 10.48550/arxiv.2609.20936
UR - https://hal.science/hal-05763136v1
AB - AutoTherm is a modular code automating the determination of thermal production and interaction rates for cosmology from Thermal Field Theory. This first release computes fully automatically the leading-order contribution from ultrarelativistic 2↔ 2 processes to the production rate of an off-equilibrium ϑ particle coupled to a thermal bath. It takes as input a FeynRules model file describing the Lagrangian of the bath-ϑ system. The AutoTherm program consists of a Wolfram package, which utilises FeynArts/FormCalc, together with a few Python modules for symbolic and numerical routines. Their combined usage leads from the model file to the rate, but each component can also be used in a standalone manner. The main strength of this release is the automated, model-independent handling of Hard Thermal Loop resummation, which is necessary whenever a 2↔ 2 process is mediated by a t-channel massless mediator. Developments in Thermal Field Theory reduce the apparently large model dependence to the determination of the thermal mass of the mediator, which we automate successfully. They further allow us to provide three leading-order-equivalent implementations of HTL resummation. Their spread provides a first estimate of the theory uncertainty from higher-order thermal corrections. We showcase the strength of our AutoTherm framework by successfully reproducing or correcting a host of results in the literature, such as the thermal production rate of ultrarelativistic right-handed neutrinos, of gravitons and gravitinos, of axions and of dark photons.
ER -