Q&A:

Audience: There’s a part of the LQG community that doesn’t take the dynamics of GR as fundamental. Also the fundamental problems faced by researchers in LQG don’t have to do with the dynamics of GR.

Harvey: Point taken.

Harvey: In QFT the problem is connecting the UV to the IR. The real problem with a theory that doesn’t exist mathematically is whether you can start where you want in the UV and how to get to the IR. 

String theory doesn’t have a full description of what the fundamental degrees of freedom are. 

Audience: What about the other jeopardy game where you answer fundamental questions about the structure of the black hole by looking at the SYM theory. 

Harvey: In principle that can be done, but in practice it’s hard to have control over it. 

Audience: What role does SUSY play in the AdS/CFT correspondence?

Harvey: It’s not essential, but it’s a useful tool for checking it.

Audience: A worry about string theory: one uses concepts that don’t make sense without defining the metric. Doesn’t that make sense?

Harvey: That’s a valid critique; we don’t have the fundamental formulation. It only makes sense in certain limits

Audience: You said that you’re inclined to regard the two sides of a duality as surprisingly different descriptions of a single reality. Is that the most widespread view amongst practitioners? Also, if something is “gauge” at one point in the moduli space, does that really imply that it’s gauge in general?

Harvey: I think the majority do.