M-flation and its spectators

TL;DR

M-flation is a model of assisted inflation involving non-abelian matrices, which evolves towards a quadratic inflation scenario with a limited number of fields due to quantum gravity constraints.

Contribution

This paper demonstrates that M-flation with random initial conditions naturally evolves into a quadratic assisted inflation model with a bounded number of fields.

Findings

System evolves towards quadratic assisted inflation

Number of fields is bounded by quantum gravity scale

Spectator fields are fixed at the origin in the effective model

Abstract

M-flation is an implementation of assisted inflation, in which the inflaton fields are three N_c x N_c non-abelian hermitean matrices. The model can be consistently truncated to an effectively single field inflation model, with all ``spectator'' fields fixed at the origin. We show that starting with random initial conditions for all fields the truncated sector is not a late-time attractor, but instead the system evolves towards quadratic assisted inflation with all fields mass degenerate. Demanding the energy density during inflation to be below the effective quantum gravity scale, we find that the number of fields, and thus the assisted effect, is bounded N_c < 10^2.