Frequency Dependence of the Speed of Light in Space

Abstract

To characterize the possible dispersion of the velocity of light in space (vacuum) a Cauchy-type formula, $n^2=1+\frac{A}{{\nu }^2}+B{\nu }^2$, is used. It is shown that relativity only allows a nonzero $A$ term, independent of the nature of the waves or a quantization thereof. Recent experimental data provide upper bounds for $A$ and $B$, limiting thereby the dispersion in the microwave, infrared, visible, and ultraviolet regions of the spectrum to less than one part in ${10}^{20}$.