Abstract
I discuss the possibility that inflation is driven by supersymmetry breaking, with the superpartner of the goldstino (sgoldstino) playing the role of the inflaton. Imposing an R-symmetry to satisfy the slow-roll conditions, avoiding the so-called η -problem, leads to an interesting class of small field inflation models, characterised by an inflationary plateau around the maximum of scalar potential near the origin, where R-symmetry is restored with the inflaton rolling down to a minimum, describing the present phase of the Universe. Inflation can be driven by either an F- or a D-term, while the minimum has a positive tuneable vacuum energy. The models agree with cosmological observations and, in the simplest case, predict a rather small tensor-to-scalar ratio of primordial perturbations. This talk is an extended version of an earlier review (Antoniadis, 2018).
Highlights
In a recent work [1,2], we studied a simple N = 1 supergravity model having the property of relating the scales of supersymmetry (SUSY) breaking and inflation, partly motivated by string theory
The minimal field content consists of a chiral multiplet with a shift symmetry promoted to a gauged R-symmetry using a vector multiplet
In the string theory context, the chiral multiplet can be identified with the string dilaton and the shift symmetry associated to the gauge invariance of a two-index antisymmetric tensor field, dual to ascalar
Summary
Since inflation arises at a plateau around the maximum of the scalar potential (hill-top), no large field initial conditions are needed, while the pseudo-scalar companion of the inflaton is absorbed into the R-gauge field which becomes massive, leading the inflaton as a single scalar field present in the low-energy spectrum This model provides a minimal realisation of natural small-field inflation in supergravity, compatible with present observations, as we show below. It allows the presence of a realistic minimum describing our present Universe with an infinitesimal positive vacuum energy, arising due to a cancellation between an. The first part describing the F-term is a short summary of an earlier review [27] which was added for self consistency and convenience of the reader
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