TY - JOUR

T1 - Tachyonic preheating in Palatini R 2inflation

AU - Karam, Alexandros

AU - Tomberg, Eemeli

AU - Veerm e, Hardi

PY - 2021/6/11

Y1 - 2021/6/11

N2 - We study preheating in the Palatini formalism with a quadratic inflaton potential and an added αR 2 term. In such models, the oscillating inflaton field repeatedly returns to the plateau of the Einstein frame potential, on which the tachyonic instability fragments the inflaton condensate within less than an e-fold. We find that tachyonic preheating takes place when α ⪆ 1013 and that the energy density of the fragmented field grows with the rate Γ/H ≈ 0.011 α0.31. The model extends the family of plateau models with similar preheating behaviour. Although it contains non-canonical quartic kinetic terms in the Einstein frame, we show that, in the first approximation, these can be neglected during both preheating and inflation.

AB - We study preheating in the Palatini formalism with a quadratic inflaton potential and an added αR 2 term. In such models, the oscillating inflaton field repeatedly returns to the plateau of the Einstein frame potential, on which the tachyonic instability fragments the inflaton condensate within less than an e-fold. We find that tachyonic preheating takes place when α ⪆ 1013 and that the energy density of the fragmented field grows with the rate Γ/H ≈ 0.011 α0.31. The model extends the family of plateau models with similar preheating behaviour. Although it contains non-canonical quartic kinetic terms in the Einstein frame, we show that, in the first approximation, these can be neglected during both preheating and inflation.

U2 - 10.1088/1475-7516/2021/06/023

DO - 10.1088/1475-7516/2021/06/023

M3 - Journal article

AN - SCOPUS:85108945658

VL - 2021

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 6

M1 - 023

ER -