# Electromagnetically and gravitationally stealth fields

## TL;DR

This paper introduces a class of complex scalar field models that are 'stealth' configurations, having zero energy-momentum tensor and electric current, yet influencing gravitational and electromagnetic couplings.

## Contribution

It constructs a new class of stealth scalar field models that modify effective gravitational and electromagnetic interactions without contributing to energy or charge.

## Key findings

- Stealth fields have vanishing energy-momentum tensor and electric current.
- They can alter the effective strength of gravity and electromagnetism.
- Stealth configurations lead to re-scaling of electric charge and Newton's constant.

## Abstract

We construct a generic class of models for complex scalar fields -- minimally coupled to gravity and electromagnetism -- with the property that their energy-momentum tensor and the electric current vanish for certain massive configurations. These are electromagnetically and gravitationally {\it stealth fields}. We shall see that the latter configurations can affect, in addition, the strength of the gravity-matter and electromagnetic-matter couplings of other (non-stealth) modes present in the system, which turn out to be equivalent to the re-scaling the electric charge and the Newton constant (with a stealth-mass depending factor).