Inflation and Uplifting with Nilpotent Superfields

TL;DR

The paper develops a broad class of supergravity inflationary models that incorporate uplifting to a small positive cosmological constant using nilpotent chiral multiplets (Volkov–Akulov framework). It shows that a single nilpotent multiplet can yield simple, stable inflationary potentials of the form V(φ) = |f(φ/√2)|^2 + V0, with V0 tunable via W0 and SUSY-breaking scales, avoiding moduli problems. It further extends to two nilpotent multiplets, which simplifies the bosonic sector even more and allows explicit constructions where the inflaton dynamics are decoupled from stabilized scalars while maintaining controlled uplift and SUSY breaking. The work provides practical models for uplifted chaotic inflation in supergravity and links to string-theoretic uplifting mechanisms and D-brane goldstinos, suggesting a versatile toolkit for cosmology within a SUSY framework.

Abstract

Recently it was found that a broad class of existing inflationary models based on supergravity can be significantly simplified if some of the standard, unconstrained chiral superfields are replaced by nilpotent superfields, associated with Volkov-Akulov supersymmetry. The same method allows to simplify the existing models of uplifting of AdS vacua in string theory. In this paper we will show that one can go well beyond simplifying the models that already exist. We will propose a broad class of new models of chaotic inflation based on supergravity with nilpotent superfields, which simultaneously incorporate both inflation and uplifting. They provide a simple unified description of inflation and the present acceleration of the universe in the supergravity context.