Beyond the Singularity of the 2-D Charged Black Hole

TL;DR

This paper explores the geometry and wavefunction behavior of two-dimensional charged black holes in string theory, revealing that charge influences wave smoothness at singularities and allows transmission through them, affecting external physics.

Contribution

It demonstrates that charged black holes in string theory have smooth wavefunctions at singularities and permit wave transmission, unlike uncharged cases, impacting the understanding of black hole interiors.

Findings

Wavefunctions are smooth at singularities for charged black holes.

Part of the wave can transmit through the singularity in charged cases.

External physics is influenced by conditions behind the past singularity.

Abstract

Two dimensional charged black holes in string theory can be obtained as exact (SL(2,R)xU(1))/U(1) quotient CFTs. The geometry of the quotient is induced from that of the group, and in particular includes regions beyond the black hole singularities. Moreover, wavefunctions in such black holes are obtained from gauge invariant vertex operators in the SL(2,R) CFT, hence their behavior beyond the singularity is determined. When the black hole is charged we find that the wavefunctions are smooth at the singularities. Unlike the uncharged case, scattering waves prepared beyond the singularity are not fully reflected; part of the wave is transmitted through the singularity. Hence, the physics outside the horizon of a charged black hole is sensitive to conditions set behind the past singularity.