Einstein-Maxwell-dilaton theory in Newman-Penrose formalism

TL;DR

This paper reformulates Einstein-Maxwell-dilaton theories in the Newman-Penrose formalism, analyzing solution spaces and memory effects, revealing the dilaton's selective influence on different memory phenomena.

Contribution

It adapts the equations of motion into the NP formalism and investigates the specific role of the dilaton in gravitational memory effects.

Findings

Dilaton does not affect displacement or kick memory effects.

Dilaton contributes to the time-delayed memory effect.

Solution space asymptotic to flat spacetime was characterized.

Abstract

In this paper, we study the four dimensional Einstein-Maxwell-dilaton (EMD) theories in the Newman-Penrose (NP) formalism. We adapt the equations of motion into the NP formalism, and obtain the solution space that is asymptotic to the flat space-time. We then investigate the gravitational and electromagnetic memory effects. We find that the dilaton does not contribute to the displacement nor the kick memory effects, but it does contribute to the time-delayed memory effect.