## Video URL

https://pirsa.org/24010086# Reflecting boundary conditions in numerical relativity as a model for black hole echoes

### APA

Dailey, C. (2024). Reflecting boundary conditions in numerical relativity as a model for black hole echoes. Perimeter Institute for Theoretical Physics. https://pirsa.org/24010086

### MLA

Dailey, Conner. Reflecting boundary conditions in numerical relativity as a model for black hole echoes. Perimeter Institute for Theoretical Physics, Jan. 22, 2024, https://pirsa.org/24010086

### BibTex

@misc{ scivideos_PIRSA:24010086, doi = {10.48660/24010086}, url = {https://pirsa.org/24010086}, author = {Dailey, Conner}, keywords = {Other Physics}, language = {en}, title = {Reflecting boundary conditions in numerical relativity as a model for black hole echoes}, publisher = {Perimeter Institute for Theoretical Physics}, year = {2024}, month = {jan}, note = {PIRSA:24010086 see, \url{https://scivideos.org/pirsa/24010086}} }

Conner Dailey Perimeter Institute for Theoretical Physics

**Source Repository**PIRSA

**Collection**

**Talk Type**Scientific Series

**Subject**

## Abstract

Recently, there has been much interest in black hole echoes, based on the idea that there may be some mechanism (e.g., from quantum gravity) that waves/fields falling into a black hole could partially reflect off of an interface before reaching the horizon. There does not seem to be a good understanding of how to properly model a reflecting surface in numerical relativity, as the vast majority of the literature avoids the implementation of artificial boundaries, or applies transmitting boundary conditions. Here, we present a framework for reflecting a scalar field in a fully dynamical spherically symmetric spacetime, and implement it numerically. We study the evolution of a wave packet in this situation and its numerical convergence, including when the location of a reflecting boundary is very close to the horizon of a black hole. This opens the door to model exotic near-horizon physics within full numerical relativity.