New electromagnetic memories and soft photon theorems

Abstract

In this paper, we present a new type of electromagnetic memory. It is a ``magnetic'' type, or B mode, radiation memory effect. Rather than a residual velocity, we find a position displacement of a charged particle induced by the B mode radiation with memory. We find two types of electromagnetic displacement (ordinary and null). We also show that the null electromagnetic memory formulas are nothing but a Fourier transformation of soft photon theorems.