Effective reheating in Gauss--Bonnet inflation with μ(ϕ,X) coupling
Abstract
We study effective reheating in a scalar--Gauss--Bonnet inflationary model with a phase-space-dependent coupling μ(ϕ,X), in which a compact field-space feature is combined with a bounded kinetic gate. The modified inflationary background determines the pivot-scale quantities and the effective energy density at the end of inflation. These quantities are then used to derive the reheating duration Nre and temperature Tre through the thermal-history matching relation. We first perform two fixed-pivot reference scans by varying the overall Gauss--Bonnet strength λGB and the kinetic parameter gX separately. For the reference parameter choices, increasing either parameter increases Nre and decreases Tre for the selected reheating equations of state. Additional benchmark calculations clarify how these variations depend on the dynamical regime of the model. In the λGB scan, the increase in Nre and the decrease in Tre persist, although both variations become strongly suppressed when the coupling is more localized or when the end of inflation is controlled more strongly by the E-model potential. In the gX scan, stronger field-space localization and kinetic saturation can instead lead to a slight decrease in Nre and an increase in Tre as gX is increased. When the bounded kinetic contribution is considered together with a weaker overall Gauss--Bonnet interaction, the resulting changes in the reheating quantities become nearly negligible. The fixed-pivot predictions of the representative and alternative benchmarks are compared with CMB constraints.These reheating constraints are then discussed for four representative values of the effective equation-of-state parameter, w̅re=−1/3,0,2/3, and $1$.
Related
- Gauss--Bonnet running and the de Sitter saddle of quadratic gravity inflation
- Reconciling nonminimally coupled Higgs inflation with ACT DR6 observations through reheating
- Radiative Corrections and Reheating in Supergravity Models of Inflation
- New Effects in Multifield Cosmology Coupled to the Gauss-Bonnet Term
- Binary black hole mergers in massive Einstein-scalar-Gauss-Bonnet gravity
BibTeX
@misc{seidabadi2026effective,
title = {{Effective reheating in Gauss--Bonnet inflation with $μ(ϕ,X)$ coupling}},
author = {Ali Seidabadi and Sara Saghafi and Kourosh Nozari},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.02506},
eprint = {2608.02506},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.02506},
}
RIS
TY - UNPB
TI - Effective reheating in Gauss--Bonnet inflation with μ(ϕ,X) coupling
AU - Ali Seidabadi
AU - Sara Saghafi
AU - Kourosh Nozari
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2608.02506
UR - https://arxiv.org/abs/2608.02506
AB - We study effective reheating in a scalar--Gauss--Bonnet inflationary model with a phase-space-dependent coupling μ(ϕ,X), in which a compact field-space feature is combined with a bounded kinetic gate. The modified inflationary background determines the pivot-scale quantities and the effective energy density at the end of inflation. These quantities are then used to derive the reheating duration N_re and temperature T_re through the thermal-history matching relation. We first perform two fixed-pivot reference scans by varying the overall Gauss--Bonnet strength λ_GB and the kinetic parameter g__X separately. For the reference parameter choices, increasing either parameter increases N_re and decreases T_re for the selected reheating equations of state. Additional benchmark calculations clarify how these variations depend on the dynamical regime of the model. In the λ_GB scan, the increase in N_re and the decrease in T_re persist, although both variations become strongly suppressed when the coupling is more localized or when the end of inflation is controlled more strongly by the E-model potential. In the g__X scan, stronger field-space localization and kinetic saturation can instead lead to a slight decrease in N_re and an increase in T_re as g__X is increased. When the bounded kinetic contribution is considered together with a weaker overall Gauss--Bonnet interaction, the resulting changes in the reheating quantities become nearly negligible. The fixed-pivot predictions of the representative and alternative benchmarks are compared with CMB constraints.These reheating constraints are then discussed for four representative values of the effective equation-of-state parameter, w̅_re=−1/3,0,2/3, and $1$.
ER -