Singularity Musings

Abstract: We all believe that quantum gravity should have something to say about what happens close to the singularity. Yet, to extract such lessons from the boundary theory is a challenging endeavor. Some 20 odd years ago, Fidkowski, Hubeny, Kleban and Shenker showed that one probe of the singularity is a bouncing geodesic. These geodesics appear in the position space green function in a perhaps unnatural way, but can be easily accessed in the frequency domain as alluded to by Festuccia and Liu. I will review these results and present some preliminary thoughts on a simple modification of 2d JT gravity that also gives rise to spacelike singularities. The advantage of this 2d model is that one can potentially use them to study topology changing effects close to the singularity. This is work in progress with Adam Levine and Steve Shenker.