On the Smallness of the Cosmological Constant in SUGRA Models Inspired by Degenerate Vacua

TL;DR

This paper discusses how no-scale supergravity models, protected by global symmetries, naturally lead to a tiny cosmological constant through degenerate vacua and the multiple point principle, providing a potential explanation for the smallness of dark energy.

Contribution

It introduces a framework where global symmetries in no-scale supergravity produce degenerate vacua, naturally resulting in a tiny cosmological constant consistent with observations.

Findings

Degenerate vacua with broken and unbroken supersymmetry are realized.

The multiple point principle explains the smallness of the cosmological constant.

Global symmetries protect the vacuum energy from large quantum corrections.

Abstract

In the no-scale supergravity global symmetries protect local supersymmetry and a zero value for the cosmological constant. The breakdown of these symmetries, which ensures the vanishing of the vacuum energy density, results in a set of degenerate vacua with broken and unbroken supersymmetry leading to the natural realisation of the multiple point principle (MPP). In the MPP inspired SUGRA models the cosmological constant is naturally tiny.