Quantum Field Theory in Curved Spacetime (2nd Edition)

TL;DR

This second edition provides a comprehensive overview of mathematical aspects of quantum field theory in curved spacetimes, including recent developments and implications for black hole physics and spacetime stability.

Contribution

It updates and expands the 2006 article with new sections on Hadamard states, particle creation, stress-energy tensor, and black hole backgrounds, integrating recent results and theorems.

Findings

Analysis of black hole horizon stability

Implications of QFTCST for black hole information paradox

Comparison of recent results on Cauchy horizon instabilities

Abstract

The 2023 second edition of a 2006 encyclopedia article on mathematical aspects of quantum field theory in curved spacetimes (QFTCST). Section-titles (with new sections indicated with stars) are: Introduction and preliminaries, Construction of a $*$-algebra for a real linear scalar field on globally hyperbolic spacetimes and some general theorems, *More about (quasifree) Hadamard states, Particle creation and the limitations of the particle concept, Theory of the stress-energy tensor, *More about the intersection of QFTCST with AQFT and the Fewster-Verch No-Go Theorem, Hawking and Unruh effects, *More about (classical and) quantum fields on black hole backgrounds, Non-globally hyperbolic spacetimes and the time-machine question, *More about QFT on non-globally hyperbolic spacetimes, Other related topics and some warnings. The article contains many references. It also includes a review of, and also compares and contrasts, recent results on the implications of QFTCST for the question of the instability of three sorts of Cauchy horizon -- first those inside black holes such as especially Reissner-Nordstr\"om-de Sitter and Kerr-de Sitter, second the compactly generated Cauchy horizons of spacetimes in which time-machines get manufactured, and third the Cauchy horizon of the spacetime which is believed to describe evaporating black holes and which underlies (one version of) the black hole information-loss puzzle.