Dispersive Property of the Quantum Vacuum and the Speed of Light

TL;DR

This paper investigates how quantum vacuum properties influence light propagation, showing that linear quantum effects do not alter light speed, but nonlinear effects from the Euler-Heisenberg Lagrangian can cause small modifications.

Contribution

It introduces a detailed analysis of the dispersive properties of the quantum vacuum, incorporating nonlinear effects to predict potential modifications in the speed of light.

Findings

Linear quantum effects do not change the speed of light.

Nonlinear effects induce small corrections to the speed of light.

First-order nonlinear corrections are derived from the Euler-Heisenberg Lagrangian.

Abstract

We want to study the influence of the quantum vacuum on the light propagation. At first, by working in the standard linear quantum theory of the electromagnetic fields, it is shown that the electric permittivity and the magnetic permeability of the vacuum medium are changed; but, the resulting speed of light isn't modified. Then, taking into account nonlinear effects by considering the Euler-Heisenberg Lagrangian, the corresponding zero point (vacuum) energy and the resulting modification of the speed of light are found up to the first non-vanishing correction.