Generalized Assisted Inflation

TL;DR

The authors address inflation in multi-field settings with exponential potentials, extending the assisted inflation paradigm to include cross-couplings common in supergravity and compactifications. They derive exact scaling solutions for general multi-term potentials, providing explicit expressions for the late-time power-law exponent $p$ in decoupled, two-field, and multi-field scenarios. A key finding is that cross-couplings typically reduce the inflationary rate, though configurations with shared fields across terms can yield novel scaling behavior and, in some cases, enhanced expansion. The work links inflationary dynamics to high-energy theories and informs the viability of inflation in Kaluza-Klein and string-inspired models.

Abstract

We obtain a new class of exact cosmological solutions for multi-scalar fields with exponential potentials. We generalize the assisted inflation solutions previously obtained, and demonstrate how they are modified when there exist cross-couplings between the fields, such as occur in supergravity inspired cosmological models.