An Alternative Framework for E-Model Inflation in Supergravity

Abstract

We present novel realizations of E-model inflation within Supergravity which are largely associated with the existence of a pole of order one in the kinetic term of the (gauge-singlet) inflaton superfield. This pole arises due to the selected logarithmic Kähler potentials K1 and K1, which parameterize the same hyperbolic manifold with scalar curvature RK = −2/N , where N > 0 is the coefficient of a logarithmic term. The associated superpotential W exhibits the same R charge with the inflaton-accompanying superfield and includes all the allowed renormalizable terms. For K = K1, inflation can be attained for N = 2 at the cost of some tuning regarding the coefficients of the W terms and predicts a tensor-to-scalar ratio r at the level of 0.001. The tuning can be totally eluded for K = K1, which allows for quadratic-and quartic-like models with N values increasing with r and spectral index ns close or even equal to its present central observational value.

Formulating E- & T-Model Inflation in Supergravity

“…It is well-known [1][2][3] that the presence of a pole in the kinetic term of the inflaton gives rise to inflationary models collectively named α-attractors [4,5]. Confining ourselves to poles of order one and two, the lagrangian of the homogenous inflaton field ϕ = ϕ(t) can be written as…”

“…In this talk, based on Ref. [2,3], we present novel realizations of E and/or T-Model Inflation (ETI) in the context of Supergravity (SUGRA). Namely, in Sec.…”

Formulating E- & T-Model Inflation in Supergravity

“…Therefore, f p is generically expected to emerge also in the denominator of V SUGRA making difficult the establishment of an inflationary era. This problem can be addressed [2,3] either by tuning the terms of W so that the pole is removed from V SUGRA thanks to cancellations or adopting a more structured K which yields the desired kinetic terms in Eq. (1) but lets V SUGRA immune.…”

“…Also we assume that ETI is followed in turn by an oscillatory phase with mean equation-of-state parameter w rh , radiation and matter domination. We determine it applying the formula [3]…”

“…It is well-known [1][2][3] that the presence of a pole in the kinetic term of the inflaton gives rise to inflationary models collectively named α-attractors [4,5]. Confining ourselves to poles of order one and two, the lagrangian of the homogenous inflaton field φ = φ(t) can be written as…”