A remark on alpha vacua for quantum field theories on de Sitter space

TL;DR

This paper demonstrates that alpha vacua, proposed as quantum states on de Sitter space, exhibit infinitely strong fluctuations in typical observables like the renormalized energy-momentum tensor.

Contribution

It provides a critical analysis showing that alpha vacua have infinite fluctuations, challenging their suitability as physical states.

Findings

Alpha vacua have infinitely strong fluctuations in typical observables.

The renormalized energy-momentum tensor diverges for alpha vacua.

This casts doubt on the physical viability of alpha vacua.

Abstract

It is shown that the so-called $\alpha$-vacua which have been proposed as candidates for states of free quantum fields on de Sitter space have infinitely strong fluctuations for typical observables as averaged renormalized energy momentum tensor.