# Preheating in Palatini Higgs inflation

## TL;DR

This paper investigates preheating in Palatini Higgs inflation, revealing that Higgs excitations significantly contribute to reheating, leading to rapid radiation domination and impacting inflationary predictions.

## Contribution

It demonstrates the role of Higgs excitations in preheating within Palatini Higgs inflation, contrasting with the metric formulation, and analyzes implications for inflationary observables.

## Key findings

- Higgs excitations contribute to reheating in Palatini Higgs inflation.
- Reheating is almost instantaneous due to tachyonic Higgs production.
- Fewer e-folds are needed, affecting the spectral index.

## Abstract

We study the details of preheating in Palatini Higgs inflation. We show, that contrary to what happens in the metric formulation of the model, the Universe does not reheat through the creation of gauge bosons only, but also through the tachyonic production of Higgs excitations. The latest entropy production channel turns out to be very efficient and leads to an almost instantaneous onset of radiation domination after the end of inflation. As compared to the metric case, this reduces the number of e-folds needed to solve the usual hot big bang problems while leading to a smaller spectral index for the primordial spectrum of density perturbations.