Flop Transitions in M-theory Cosmology

TL;DR

This paper investigates flop-transitions in M-theory on Calabi-Yau three-folds, demonstrating their dynamic realization in cosmology and how hypermultiplet excitations influence the transition's completion and stability.

Contribution

It introduces the effective action including the hypermultiplet at the flop-transition and constructs explicit cosmological solutions showing the transition's dynamics.

Findings

Flop-transitions can be dynamically achieved in cosmological models.

Hypermultiplet excitations prevent the transition from completing.

The system tends to stabilize near the flop-transition region.

Abstract

We study flop-transitions for M-theory on Calabi-Yau three-folds and their applications to cosmology in the context of the effective five-dimensional supergravity theory. In particular, the additional hypermultiplet which becomes massless at the transition is included in the effective action. We find the potential for this hypermultiplet which includes quadratic and quartic terms as well as additional dependence on the Kahler moduli. By constructing explicit cosmological solutions, it is demonstrated that a flop-transition can indeed by achieved dynamically, as long as the hypermultiplet is set to zero. Once excitations of the hypermultiplet are taken into account we find that the transition is generically not completed but the system is stabilised close to the transition region. Regions of moduli space close to flop-transitions can, therefore, be viewed as preferred by the cosmological evolution.