Ramp and plateau in bulk correlators within the disk topology in JT gravity

Abstract

We study bulk two-point correlation functions of a massless scalar field in Jackiw-Teitelboim gravity around the eternal black hole saddle. While same-side correlators exhibit exponential decay, two sided correlators, at the next to leading order in steepest descent approximation, exhibit a ramp followed by a plateau after the initial semiclassical exponential decay. Our results indicate that the late-time saturation of two-sided correlators is already visible within the perturbative saddle expansion of the bulk path integral, without invoking nonperturbative e^{-S} effects. Finally, we show that the dip-time, defined as the minimum of the correlator, grows inversely with the black hole temperature, consistent with expectations from the holographic dual.