No-boundary measure and preference for large e-foldings in multi-field inflation

TL;DR

This paper investigates whether the no-boundary wave function in quantum gravity can favor long inflation periods in multi-field models, finding that a high number of fields increases the probability of sufficient inflation.

Contribution

It demonstrates that increasing the number of fields in multi-field inflation models can enhance the no-boundary wave function's probability for sufficient inflation.

Findings

Higher probability for sufficient inflation with many fields

No-boundary wave function favors large e-foldings in multi-field scenarios

Probability increases significantly when the number of fields is very high

Abstract

The no-boundary wave function of quantum gravity usually assigns only very small probability to long periods of inflation. This was a reason to doubt about the no-boundary wave function to explain the observational universe. We study the no-boundary proposal in the context of multi-field inflation to see whether the number of fields changes the situation. For a simple model, we find that indeed the no-boundary wave function can give higher probability for sufficient inflation, but the number of fields involved has to be very high.