Weyl double copy in type D spacetime in four and five dimensions

Abstract

In this paper, we present a second realization of the Weyl double copy (WDC) in four-dimensional algebraic type D spacetime. We show that any type D vacuum solution admits an algebraically general Maxwell scalar on the curved background that squares to give the Weyl scalar. The WDC relation defines a scalar field that satisfies the Klein-Gordon equation sourced by the Weyl scalar on the curved background. We then extend the type D WDC to five dimensions.