1/N Resolution to Inflationary eta-Problem

Abstract

We observe that the dominant one loop contribution to the graviton propagator in the theory of N (N>>1) light scalar fields ϕ_a (with masses smaller than M_{pl}/\sqrt{N}) minimally coupled to Einstein gravity is proportional to N while that of graviton-scalar-scalar interaction vertex is N independent. We use this to argue that the coefficient of the Rϕ_a^2 term appearing at one loop level is 1/N suppressed. This observation provides a resolution to the η-problem, that the slow-roll parameter ηreceives order one quantum loop corrections for inflationary models built within the framework of scalar fields minimally coupled to Einstein gravity, for models involving large number of fields. As particular examples, we employ this to argue in favor of the absence of η-problem in M-flation and N-flation scenarios.

1+13 pages, 3 figures

References in corpus (4)

• One-loop divergences for gravity non-minimally coupled to a multiplet of scalar fields: calculation in the Jordan frame. I. The main results
• Power Spectrum and Signatures for Cascade Inflation
• Dark Matter via Many Copies of the Standard Model
• Black Hole Entropy and Gravity Cutoff

Cited by in corpus (12)

• Gauge Fields and Inflation
• The asymptotic dS Swampland Conjecture - a simplified derivation and a potential loophole
• Rescuing Single Field Inflation from the Swampland
• Quantum Gravity Constraints on Inflation
• Gravitational Waves from Preheating in M-flation
• Gauged M-flation After BICEP2
• Single Field Inflation in Supergravity with a $U(1)$ Gauge Symmetry
• Particle Production during Inflation in Light of PLANCK
• EFT & Species Scale: Friends or foes?
• Warm Inflation with Barrow Holographic Dark Energy
• Non-Minimal M-flation
• Transient Acceleration after Non-minimal M-flation Preheating