A short overview on the Black Hole-Tower Correspondence and Species Thermodynamics

TL;DR

This paper reviews the Black Hole-Tower correspondence and Species Thermodynamics, connecting black hole transitions into light state towers with string theory spectra, and explores their implications for black hole entropy and quantum gravity.

Contribution

It introduces a unified thermodynamic framework linking black hole entropy to light state spectra across quantum gravity regimes, expanding on the Black Hole-String Correspondence.

Findings

Black holes transition into towers of light states governed by the Species Scale.

Thermodynamic constraints align with string theory predictions.

The framework enhances understanding of black hole entropy in effective field theories.

Abstract

The breakdown of gravitational effective field theories is intimately connected to the emergence of infinite towers of light states near infinite-distance limits in field space. In string theory, up to duality frame, such towers arise from Kaluza-Klein or weakly-coupled critical string oscillator modes. Motivated by the Black Hole-String Correspondence, we review a broader mechanism whereby black holes undergo a transition into a tower of light states, governed by the Quantum Gravity cutoff -- known as the Species Scale. Building on these developments, the Black Hole-Tower correspondence aims to provide a unified thermodynamic framework that describes black hole entropy in terms of the spectrum of the lightest degrees of freedom across various perturbative regimes of quantum gravity theories. In those regimes, thermodynamic consistency of such transition imposes stringent constraints on the spectrum, in agreement with string theory predictions. This defines the basis of the so-called Species Thermodynamics. In this review, we emphasize these recent advances and synthesize their implications, offering an overview of how the outlined correspondence, the species scale and related thermodynamic principles enhance our understanding of black hole entropy within the effective field theory framework.