Chain Inflation Reconsidered

Abstract

We investigate density perturbations in the chain inflation scenario, where the inflaton undergoes successive tunneling transitions along one field direction. First we show that when the bubble walls associated with such a phase transition meet, they induce the next phase transition and continue to propagate as phase interfaces. Then we present an analytical calculation of the density fluctuations and an estimate of non-Gaussianities such as f_{NL}, which we find to be small (of order 1). To get the right amplitude for the power spectrum, there have to be 10^8 phase transitions per Hubble time, a significant model building challenge. We find that working models of chain inflation must be rather strongly coupled, and thus have a very limited range of validity as effective field theories. We discuss generalizations to the multiple field case, the curvaton scenario, and noncanonical kinetic terms.

15 pages, 6 figures; added references, fixed minor typos

References in corpus (9)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• How to Run Through Walls: Dynamics of Bubble and Soliton Collisions
• A Wrinkle in Coleman - De Luccia
• Slow nucleation rates in Chain Inflation with QCD Axions or Monodromy
• Simplified Chain Inflation
• Resonant Tunneling in Scalar Quantum Field Theory
• Chain inflation and the imprint of fundamental physics in the CMBR
• Quadra-Spectrum and Quint-Spectrum from Inflation and Curvaton Models
• Gravity Waves from Chain Inflation

Cited by in corpus (7)

• The landscape of QCD axion models
• Inflation, Cosmic Perturbations and Non-Gaussianities
• On the Unlikeliness of Multi-Field Inflation: Bounded Random Potentials and our Vacuum
• Multi-Stream Inflation in a Landscape
• The Power Spectrum of Density Perturbations in Chain Inflation
• Classical Transitions for Flux Vacua
• Rolling Through a Vacuum