Superluminal Propagation Caused by Radiative Corrections in a Uniform Electromagnetic Field

TL;DR

This paper investigates how radiative corrections in a uniform electromagnetic field can alter the maximum propagation velocity of neutral scalar fields, potentially leading to superluminal speeds without violating causality.

Contribution

It demonstrates that radiative corrections can cause neutral scalar fields to propagate faster than light in a uniform electromagnetic field, a novel effect not previously detailed.

Findings

Maximum velocity of scalar fields can exceed unity due to radiative corrections.

Superluminal propagation depends on the reference frame but does not violate causality.

The effect is shown explicitly in a Yukawa interaction model with charged Dirac fields.

Abstract

We consider the effect of radiative corrections on the maximum velocity of propagation of neutral scalar fields in a uniform electromagnetic field. The propagator of neutral scalar fields interacting with charged fields depends on the electromagnetic field through charged particle loops. The kinetic terms of the scalar fields are corrected and the maximum velocity of the scalar particle becomes greater or less than unity. We show that the maximum velocity becomes greater than unity in a simple example, a neutral scalar field coupled with two charged Dirac fields by Yukawa interaction. The maximum velocity depends on the frame of reference and causality is not violated. We discuss the possibility of this superluminal propagation in the Standard Model.