Absorption vs Decay of Black holes in string theory and T-symmetry

TL;DR

This paper explores how T-symmetry in string theory models of black holes can reconcile classical absorption properties with quantum state degeneracy, linking microscopic models to classical black hole behavior.

Contribution

It demonstrates that T-symmetric microscopic models can account for classical black hole absorption, aligning quantum degeneracy with classical cross-section calculations.

Findings

Classical absorption arises from quantum state degeneracy.

Microscopic models reproduce classical absorption cross-sections.

T-symmetry offers a new perspective on black hole emission and absorption.

Abstract

Classically a black hole can absorb but not emit energy. We discuss how this T-asymmetric property of black holes arises in the recently proposed (T-symmetric) microscopic models of black holes based on bound states of D-branes. In these string theory based models, the nonvanishing classical absorption is made possible essentially by the exponentially increasing degeneracy of quantum states with mass of the black hole. The classical limit of the absorption crosssection computed in the microscopic model agrees with the result obtained from a classical analysis of a wave propagating in the background metric of the corresponding black hole (upto a numerical factor).