On the consistency of de Sitter vacua

TL;DR

This paper investigates the theoretical consistency of de Sitter invariant alpha-vacua, analyzing their properties and potential issues, and concludes they may still be applicable to inflation despite some problems.

Contribution

It provides a detailed analysis of the non-renormalization and non-standard properties of alpha-vacua, clarifying their viability for inflationary models.

Findings

Alpha-vacua exhibit non-renormalization issues and non-standard Green's function properties.

Non-thermal characteristics of alpha-vacua are identified.

Problems do not necessarily exclude their use in inflationary scenarios.

Abstract

In this paper the consistency of the de Sitter invariant $\alpha $-vacua, which have been introduced as simple tools to study the effects of transplanckian physics, is investigated. In particular possible non renormalization problems are discussed, as well as non standard properties of Greens functions. We also discuss the non thermal properties of the $\alpha $-vacua and the necessity of $\alpha$ to change. The conclusion is that non of these problems necessarily exclude an application of the $\alpha $-vacua to inflation.