Effective Quantum Theory of Black Hole Horizons

TL;DR

This paper develops an effective quantum framework for black hole horizons based on local geometry, deriving the area spectrum and entropy with quantum corrections, extending to scalar fields.

Contribution

It introduces a novel quantum description of black hole horizons using local geometry and Hamiltonian charges, deriving the area spectrum and entropy with corrections.

Findings

Horizon area is linked to Lorentz symmetry generators.

Area spectrum is quantized with integer or half-integer labels.

Entropy includes exponentially suppressed corrections to the area law.

Abstract

In this paper, we develop an effective quantum theory of black hole horizons using only the local horizon geometry. On the covariant phase space of the Holst action admitting Weak Isolated Horizon as an inner boundary, we construct Hamiltonian charges corresponding to Lorentz symmetries. We show that horizon area is the Hamiltonian charge corresponding to Lorentz boosts as well as that for Lorentz rotation which acts on $2$-sphere cross-sections of the horizon. Using this expression of area as a generator of Lorentz rotation, and the fact that quantum states residing on the horizon cross-sections carry a representation of $ISO(2)$, we derive the spectrum of area operator on the horizon. The eigenstates of this area operator are shown to be labelled by integers or half integers. The entropy is obtained completely in terms of these \emph{area quanta} residing on the horizon, and is shown to have exponentially suppressing corrections to the area law. The formalism is also extended to non-minimally coupled scalar fields, where the area operator gets modified due to the value of the scalar field on the horizon.