Abstract

We discuss correlators of light probe fields in heavy excited states in AdS3 gravity and holographic 2d CFTs. In the bulk, the propagator of free fields in backgrounds containing a conical defect or a BTZ black hole can be obtained by solving the wave equation, as well as by the method of images. On the boundary, these geometries are sourced by heavy operator insertions, and the propagator is dual to a HHLL correlator. By matching its expansion in Virasoro blocks to our bulk results, we determine the OPE coefficients of all contributing states in both the s and t channels. In the s channel, these states are excitations of the light field on top of the heavy state; their OPE coefficients are the amplitudes to create them. Meanwhile, t-channel OPE is dominated by the Virasoro vacuum block, but there is also an infinite family of light two-particle states that contribute to the regular part of the OPE . The OPE coefficients that couple these states to the heavy operators represent their expectation values in heavy backgrounds. We determine them exactly, give an asymptotic formula at large twist, and discuss their behavior near and above the BTZ threshold, where they become thermal one-point functions.