Alpha-Vacua, Black Holes, and AdS/CFT

TL;DR

This paper constructs and analyzes new alpha-vacua for black holes in various spacetimes, exploring their causal structure, dual CFT states, and thermal properties, extending the concept of alpha-vacua beyond de Sitter space.

Contribution

It introduces a method to create alpha-vacua for Schwarzschild, Schwarzschild-AdS, and Schwarzschild-de Sitter black holes using involutions and Bogoliubov transformations, and studies their properties.

Findings

Alpha-vacua can be constructed for black holes via involutions and mode transforms.

Causal structure of black holes may mitigate issues present in de Sitter alpha-vacua.

Dual CFT alpha-states are obtained through boundary operator mixing.

Abstract

The Schwarzschild, Schwarzschild-AdS, and Schwarzschild-de Sitter solutions all admit freely acting discrete involutions which commute with the continuous symmetries of the spacetimes. Intuitively, these involutions correspond to the antipodal map of the corresponding spacetimes. In analogy with the ordinary de Sitter example, this allows us to construct new vacua by performing a Mottola-Allen transform on the modes associated with the Hartle-Hawking, or Euclidean, vacuum. These vacua are the `alpha'-vacua for these black holes. The causal structure of a typical black hole may ameliorate certain difficulties which are encountered in the case of de Sitter alpha-vacua. For Schwarzschild-AdS black holes, a Bogoliubov transformation which mixes operators of the two boundary CFT's provides a construction of the dual CFT alpha-states. Finally, we analyze the thermal properties of these vacua.