Troubleshooting null energy density in quantum field theory

by Dr Jackson Fliss (University of Cambridge (UK))

Thursday Jul 18, 2024, 5:00 PM → 6:00 PM Europe/Athens

B228 (ΘΕΕ02)

Abstract: Classical energy conditions play an important role in determining physically realizable spacetimes in general relativity. However pointwise energy conditions are violated in quantum field theory presenting a potential problem for semi-classical gravity coupled to quantum fields. I will describe attempts, some old, some more recent, in remedying this. Namely, I will describe the status of lower bounds on the null energy density averaged over a region of spacetime, the contexts in which such bounds can be proven, when those proofs fail, and how to interpret those failures in the context of effective field theory. Lastly, time permitting, I will discuss recent and ongoing work on deriving robust criteria for when null energy (averaged over a region) is bounded below in conformal field theories.