Preheating in Einstein-Cartan Higgs Inflation: oscillon formation

Abstract

We make use of classical lattice simulations in 3+1 dimensions to study the preheating stage of Higgs Inflation in Einstein-Cartan gravity. Focusing for concreteness on a simplified scenario involving the seminal Nieh-Yan term, we demonstrate the formation of dense and spatially localized oscillon configurations constituting up to 70% of the total energy density. The emergence of these meta-stable objects may lead to a prolonged period of matter domination, effectively modifying the post-inflationary history of the Universe as compared to the metric and Palatini counterparts. Notably, the creation of oscillons comes together with a significant gravitational wave signal, whose typical frequency lies, however, beyond the range accessible by existing and planned gravitational wave experiments. The impact of the Standard Model gauge bosons and fermions and the potential extension of our results to more general Einstein-Cartan settings is also discussed.

Present and future of C osmo

“…We plan to implement the simulation of gravitational waves from an SU( 2) sector (formed by Φ and B a µ ) in the near future. CosmoLattice has been used to compute the gravitational waves produced by different early Universe sources, such as preheating and other post-inflationary resonance phenomena [123,125,161], cosmic strings [126,186], or oscillons [187].…”

“…Since its public release in February 2021, CosmoLattice has been used to explore different aspects of the non-linear dynamics of the early Universe, including: (p)reheating after inflation [158,160,161,[175][176][177][178][179][180], the impact of such era on inflationary CMB observables [158,160,161], the generation of a relic density of dark matter [130-133, 333, 334], the production of primordial gravitational waves from oscillating scalar fields [122,123,125,161,177], the study of scalar theories with nonminimal gravitational interactions [132, 279,280,335,336] and axion-gauge interactions [200], cosmic defects and associated gravitational wave production [126,186,337], phase transitions [338], and oscillons [187,339].…”

Rescuing gravitational-reheating in chaotic inflation

“…In its simplest avatar, the inflationary stage is driven by a slowly rolling scalar field whose energy density dominates the Universe at some early epoch and is eventually converted into a radiation bath, (re)heating the Universe and signaling the onset of radiation domination [3][4][5][6]. Depending on the model under consideration, this relocation of energy can take place via perturbative decays [7][8][9] or involve highly nonlinear and non-perturbative effects such as parametric resonance [10][11][12][13], tachyonic instabilities [14][15][16][17][18][19], oscillon formation [20][21][22][23][24] and turbulent energy cascades [25,26], in isolation or co-existence [27,28].…”