Speaker
Description
In this talk, I will describe a large-N wormhole saddle in the Sachdev–Ye–Kitaev (SYK) model for the variance of a heavy operator’s thermal one-point function across realizations of the microscopic couplings. I will argue that this saddle describes a double-trumpet geometry. In the double-scaling limit of SYK, the wormhole defines a quantum transition amplitude in an emergent bulk Hilbert space of chords connecting the two boundaries. In the Schwarzian limit, these chords proliferate, giving a transition amplitude in the open-universe Hilbert space of Jackiw–Teitelboim (JT) gravity. Comparing the SYK and JT amplitudes provides a direct test of heavy-operator randomness in SYK. Time permitting, I will discuss the bulk structure of the half-wormhole for a fixed realization of the couplings, and the relation betwen the bulk Hilbert spaces of the wormhole and the baby universe Hilbert space.