De Sitter Light-Ray Operators

TL;DR

This paper explores light-ray operators in four-dimensional de Sitter space, revealing that their properties differ from Minkowski space and depend on the observer, with explicit constructions and analysis in a scalar theory.

Contribution

It introduces and constructs four distinct de Sitter light-ray operators, analyzing their properties and differences from Minkowski space counterparts.

Findings

Constructed four de Sitter light-ray operators.

Demonstrated their symmetry and positivity properties.

Showed their observer dependence and distinctions from Minkowski analogs.

Abstract

In this work, we initiate the study of light-ray operators in four-dimensional de Sitter space focusing on null integrals of the stress tensor. In Minkowski space, the null integral of the stress tensor unifies several ostensibly different constructions, functioning simultaneously as the energy flux operator, the angular contribution to a conserved charge, the averaged null energy operator, and the light transform of the stress tensor. However, we show that the de Sitter analogs of these various interpretations do not necessarily coincide but rather lead to distinct, observer-dependent light-ray operators. We construct four such de Sitter analogs and analyze their matrix elements in a free, conformally coupled scalar theory, showing that they exhibit the expected symmetry and positivity properties.