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SITP Seminar presents "Bulk reconstruction and butterflies in dS JT gravity"

Event date: 
Friday, October 16, 2020 - 2:00 pm
Speaker: 
Andreas Blommaert
Abstract: 

We will be searching for evidence of the butterfly effect in dS JT gravity, which means computing out of time ordered correlators. The boundary of two dimensional dS is a circle at infinite time. Out of time ordered correlators (or any dynamical correlator) in dS are therefore bulk correlators. Computing bulk correlators in quantum gravity comes with difficulties, such as the fact that we must specify gravitational dressing to make the observables physical (diff invariant). We will deal with this. The resulting formulas have an interpretation as implementing bulk operator reconstruction in quantum gravity. There is an additional layer when trying to compute out of time ordered bulk correlators. How do we implement the folding of the time contour in a practical calculation? We will discuss a proposal for that, within the context of Schwarzian perturbation theory. Roughly speaking this proposal is to go to the second sheet of Euclidean Schwarzian correlation functions. The bulk correlator on this second sheet grows exponentially with time, with the maximal Lyapunov exponent.

 

References: It would help to know the basics of Schwarzian perturbation theory and the structure of the Schwarzian 4 point function, see sections 4.1 and 4.2 of 1606.01857 and section 3.5 of 1711.08482. Knowledge of previous discussion on bulk matter correlators in AdS JT gravity would also come in handy, see sections 1.1 and 2.1 and appendix B in 1902.11194.