Self-resonance preheating in deformed attractor models: oscillon formation and evolution

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Hauptverfasser: Gu, Bao-Min, Zhang, Yu-Peng, Shu, Fu-Wen, Liu, Yu-Xiao
Format: Preprint
Veröffentlicht: 2026
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author Gu, Bao-Min
Zhang, Yu-Peng
Shu, Fu-Wen
Liu, Yu-Xiao
author_facet Gu, Bao-Min
Zhang, Yu-Peng
Shu, Fu-Wen
Liu, Yu-Xiao
contents It is well known that, in potentials that are quadratic near the minimum but shallower away, such as small $α$ ($\ll M_P^2$) attractors, the inflaton condensate fragments into localized compact objects known as oscillons during self-resonance preheating. In this work we investigate the self-resonance in deformed $α$-attractor T-model with a Gaussian feature near the minimum, distant from inflation's end. Linear analysis reveals altered resonance bands and deformed Floquet charts dependent on feature parameters. In fully nonlinear lattice simulations, we find that the gradient energy transfer is largely independent of the potential feature parameter $h$. In contrast, after resonance terminates, the subsequent evolution of gradient energy becomes strongly dependent on $h$. Statistical analysis reveals that models with the potential feature produce larger number of smaller oscillons, with a reduced energy stored in these objects, increasingly suppressed as the magnitude of $h$ grows. By tracking the total energy and the gradient energy contained in oscillons, we find that in models with nonzero $h$ oscillons are systematically shorter-lived, with this effect strengthening for larger $h$. The gravitational wave emission is dominated by the resonance stage and is strongly suppressed once oscillons form. Potential features leave the low-frequency spectrum largely unchanged but significantly modify the high-frequency tail. Although a complete reheating description requires external couplings and higher-resolution simulations, clear qualitative differences of cosmic expansion history already emerge within our simulated time window. These results highlight the important role of potential features in shaping reheating dynamics and their cosmological implications, and provide a deeper understanding of preheating dynamics and the properties of oscillons.
format Preprint
id arxiv_https___arxiv_org_abs_2602_07972
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Self-resonance preheating in deformed attractor models: oscillon formation and evolution
Gu, Bao-Min
Zhang, Yu-Peng
Shu, Fu-Wen
Liu, Yu-Xiao
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
It is well known that, in potentials that are quadratic near the minimum but shallower away, such as small $α$ ($\ll M_P^2$) attractors, the inflaton condensate fragments into localized compact objects known as oscillons during self-resonance preheating. In this work we investigate the self-resonance in deformed $α$-attractor T-model with a Gaussian feature near the minimum, distant from inflation's end. Linear analysis reveals altered resonance bands and deformed Floquet charts dependent on feature parameters. In fully nonlinear lattice simulations, we find that the gradient energy transfer is largely independent of the potential feature parameter $h$. In contrast, after resonance terminates, the subsequent evolution of gradient energy becomes strongly dependent on $h$. Statistical analysis reveals that models with the potential feature produce larger number of smaller oscillons, with a reduced energy stored in these objects, increasingly suppressed as the magnitude of $h$ grows. By tracking the total energy and the gradient energy contained in oscillons, we find that in models with nonzero $h$ oscillons are systematically shorter-lived, with this effect strengthening for larger $h$. The gravitational wave emission is dominated by the resonance stage and is strongly suppressed once oscillons form. Potential features leave the low-frequency spectrum largely unchanged but significantly modify the high-frequency tail. Although a complete reheating description requires external couplings and higher-resolution simulations, clear qualitative differences of cosmic expansion history already emerge within our simulated time window. These results highlight the important role of potential features in shaping reheating dynamics and their cosmological implications, and provide a deeper understanding of preheating dynamics and the properties of oscillons.
title Self-resonance preheating in deformed attractor models: oscillon formation and evolution
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2602.07972