On Number of Nflation Fields

TL;DR

This paper analyzes the Nflation model with multiple scalar fields, finding that the number of fields must be limited to sustain slow roll inflation, aligning with black hole physics constraints.

Contribution

It establishes a quantitative bound on the number of scalar fields in Nflation models necessary for successful inflation.

Findings

Slow roll inflation region disappears when number of fields exceeds (M_p / 5)^2

The bound on the number of fields is consistent with black hole physics arguments

Provides a criterion for the viability of Nflation models

Abstract

We study the Nflation model, in which a collection of massive scalar fields drive the inflation simultaneously. We find, when the number of fields is larger than the square of ratio of the Planck scale $M_p$ to the average value $\bar m$ of fields masses, the slow roll inflation region will disappear. This suggests that in order to make Nflation responsible for our observable universe, the number of fields driving the Nflation must be bounded by the above ratio. This result is also consistent with recent arguments from black hole physics.