# Clocks and Rods in Jackiw-Teitelboim Quantum Gravity

## TL;DR

This paper develops a boundary-intrinsic coordinate system in JT gravity to compute exact diff-invariant bulk correlators, revealing quantum effects dominate near the horizon and resolve the information paradox.

## Contribution

It introduces a boundary-intrinsic radar definition for bulk coordinates in JT gravity, enabling exact calculations of diff-invariant correlators and insights into quantum effects near the horizon.

## Key findings

- Quantum gravity effects dominate near-horizon matter correlations.
- Classical curved spacetime models are inadequate for near-horizon physics.
- Rindler geometry breaks down at Planck-scale distances from the horizon.

## Abstract

We specify bulk coordinates in Jackiw-Teitelboim (JT) gravity using a boundary-intrinsic radar definition. This allows us to study and calculate exactly diff-invariant bulk correlation functions of matter-coupled JT gravity, which are found to satisfy microcausality. We observe that quantum gravity effects dominate near-horizon matter correlation functions. This shows that quantum matter in classical curved spacetime is not a sensible model for near-horizon matter-coupled JT gravity. This is how JT gravity, given our choice of bulk frame, evades an information paradox. This echoes into the quantum expectation value of the near-horizon metric, whose analysis is extended from the disk model to the recently proposed topological completion of JT gravity. Due to quantum effects, at distances of order the Planck length to the horizon, a dramatic breakdown of Rindler geometry is observed.