Non-perturbative Discrete Spectrum of Interior Length and Timeshift in Two-sided Black Hole

TL;DR

This paper constructs non-perturbative operators for interior length and horizon timeshift in two-sided black holes, revealing their discrete spectra and time evolution, including maximal uncertainty after the Heisenberg time.

Contribution

It introduces a non-perturbative framework for analyzing interior length and timeshift in black holes, demonstrating their discrete spectra and dynamic behavior.

Findings

Finite densities of states imply discrete spectra.

Early time distributions are sharply peaked at classical values.

Post-Heisenberg time distributions become uniform, indicating maximal uncertainty.

Abstract

We study the spectrum of the interior length and the horizon timeshift of a two-sided black hole by constructing non-perturbative length and timeshift operators in Jackiew-Teitelboim gravity. We first construct projection operators onto the fixed length or fixed horizon timeshift subspaces using the replica trick. We calculate the densities of state for the length and the timeshift, which are found to be finite. This finiteness implies the discreteness in the spectrum of these quantities. We then construct the non-perturbative length and timeshift operators, and apply them to study the time evolution of the two-sided black hole. We find that at early time, the probability distribution of the interior length and the timeshift are sharply peaked at the classical values, while after the Heisenberg time, the distribution is completely uniform over all possible values of the length and the timeshift, indicating maximal uncertainty. In particular, the probability of having the negative timeshift states, which corresponds to the white hole probability, is $O(1)$ after the Heisenberg time.