Gravity waves from cosmic bubble collisions

Understand

Our local Hubble volume might be contained within a bubble that nucleated in a false vacuum with only two large spatial dimensions.

• We study bubble collisions in this scenario and find that they generate gravity waves, which are made possible in this context by the reduced symmetry of the global geometry.
• These gravity waves would produce B-mode polarization in the cosmic microwave background, which could in principle dominate over the inflationary background.