Ko Sanders on May 19, 2014
Slides (external link)
In recent years our community has produced a large number of papers related to free electromagnetic fields in a generally covariant setting. This begs the question: Is there really something new and interesting to learn about such a free theory, or is it much ado about nothing? In this talk I aim to dispel some of the recent confusion about free electromagnetism (EM) and explain the lessons that can be learnt by taking a generally covariant perspective. After a brief discussion of the properties that one may require of a theory of free EM, I present the main results of recent work with Dappiaggi and Hack, in the context of other recent publications. Our work clarifies several issues surrounding gauge invariance and locality, using well-established, general principles, but sometimes applied in a new way. This leads to a rather tight, conceptually clear framework, which is consistent with all experiments, including Gauss’ law and the Aharonov-Bohm effect. We indicate how our new insights could help to understand more general gauge theories and we discuss some opportunities for further research in this direction.
Electromagnetism, local covariance, the Aharonov-Bohm effect and Gauss' law