Modave Lectures on Horizon-Size Microstructure, Fuzzballs and Observations

TL;DR

This paper reviews the fuzzball paradigm and microstate geometries as potential solutions to the black hole information paradox, discussing recent phenomenological developments and observational prospects.

Contribution

It provides a comprehensive overview of fuzzball solutions, including microstate geometries and superstrata, highlighting recent advances and observational implications.

Findings

Fuzzball paradigm offers a potential resolution to the information paradox.

Recent developments suggest observable signatures of fuzzballs in gravitational wave data.

Microstate geometries can mimic black hole phenomenology while avoiding singularities.

Abstract

These lecture notes discuss various aspects of the fuzzball paradigm, microstate geometries, and their role in gravitational phenomenology. We briefly introduce the information paradox and discuss how the fuzzball paradigm aims to resolve it. Then, some important families of fuzzball solutions in supergravity, called microstate geometries, are explored: multi-centered bubbling geometries and superstrata. Finally, we will review some very recent developments of the phenomenology of fuzzballs and delineate the exciting opportunities as well as the limitations of studying fuzzballs as alternatives to black holes in current and future observations.