Testing Eternal Inflation – Matthew Johnson

Date: Tue. December 8th, 2015, 11:30 am-12:30 pm

The theory of eternal inflation in an inflaton potential with multiple vacua predicts that our universe is one of many bubble universes nucleating and growing inside an ever-expanding false vacuum. The collision of our bubble with another could provide an important observational signature to test this scenario. In this talk I will summarize recent work providing a quantitative connection between the scalar field lagrangian underlying eternal inflation and the observational signature of bubble collisions. I will also summarize existing constraints and forecasts for future searches using CMB and LSS, as well as discuss the general relevance of this work for assessing fine-tuning problems in inflationary cosmology.