Excavations at the gravitationally collapsed site: Recent findings

TL;DR

This paper introduces a new coordinate system and semi-classical methods to analyze what infalling observers perceive at black hole horizons, clarifying longstanding debates about quantum effects and local observables.

Contribution

It presents a novel regular coordinate system and a semi-classical framework to study local quantum effects at black hole horizons, addressing previous ambiguities.

Findings

New regular coordinate system for black hole horizons

Link between detector response and effective temperature

Analysis of local energy density and flux near horizons

Abstract

Hawking effect was dug out of the gravitationally collapsed site forty years back when it was realised that quantum effects at the horizon could propagate outward to infinity giving rise to a thermal flux at late-times. However, the situation regarding non-asymptotic observers was never completely clear. Also, recently a debate has sprung in the community as to what would infalling observers perceive while crossing the horizon. We set out to settle this question and more at least semi-classically in the articles [arXiv:1304.2858] and [arXiv:1404.0684] with a fresh approach. We introduce a new set of coordinates that are regular everywhere, consider the adiabatic expansion of detector response and its link to the trajectory-dependent `effective' temperature/s and also local invariant observables, energy density and flux, built from renormalized stress energy tensor. This paper is a concise summary of the new procedure and the results obtained thereof.