Eur. Phys. J. D (2013) 67: 219
https://doi.org/10.1140/epjd/e2013-40290-3

Comment

Comment on: The quantum vacuum as the origin of the speed of light

Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany

^a e-mail: step.schiller@uni-duesseldorf.de

Received: 7 May 2013
Published online: 1 November 2013

Abstract

In a recent paper, Urban et al. [Eur. Phys. J. D 67, 58 (2013)] propose a model of the vacuum that predicts a fluctuating speed of light. Here, it is pointed out that under certain assumptions, past experiments strongly constrain the strength of such fluctuations, to a level smaller by approximately 8 orders compared with the estimate given in the paper.