Searches for new vacua 1: Bubbles in our universe
New vacua different from our own is a major ingredient of any landscape resolution of naturalness problems. In this talk, I will discuss models where the existence of other vacua can be probed in a non-lethal manner. Vacua that are different from our own can appear and disappear as you universe cools down, or as density of matter change. In special cases, these vacua can be accessed and leave very distinct signature.
I will focus on a special case where a bubble can be created during a supernova explosion when matter density undergoes a rapid change. New vacua which have lower energy density than our vacua, but only at finite density, provide an example where the resulting bubble would be confined to a region of space. The expansion and contraction of the bubbles can last for hundreds of years, making them observable long after a supernova explosion. I will also discuss the signatures that may appear near a supernova remnant due to the formation and propagation of a confined bubble.