ITMP seminar, May 10, 2023
Speaker: Bendeguz Offertaler, Princeton University
Title: Chaos and the reparametrization mode on the AdS_2 String
Abstract: Out-of-time-order correlators (OTOCs) are a simple diagnostic of quantum chaos. It is known that the four-point OTOC of fluctuations on the fundamental string in AdS displays Lyapunov growth at early times with the Lyapunov exponent saturating the chaos bound. This talk, based on arxiv.org/abs/2212.14842 in collaboration with S. Giombi and S. Komatsu, will focus on the string OTOC in a double scaling limit that interpolates between the Lyapunov regime at early times and exponential decay at late times. The double scaled OTOC can be obtained exactly and takes the same functional form as the OTOC in JT gravity. After first reviewing the Wilson loops / strings duality in AdS/CFT and the set-up of our analysis, I will discuss how the double scaled OTOC can be understood in terms of a high energy scattering process on the string worldsheet, with the scattering interaction governed by the worldsheet S-matrix of the long string in flat space. A complementary approach is to study the fluctuations of the string in conformal gauge, in which a key role is played by the dynamical reparametrization mode on the boundary, which is governed by a non-local effective action. The OTOC in the double scaling limit can be obtained from the reparametrization action by resumming a subset of diagrams expected to dominate in the limit. In this approach, the reparametrization action on the AdS_2 string plays an analogous role to the Schwarzian action in JT gravity.
28 май 2024
