Understanding free electromagnetism in the light of general covariance.

Algebraic Quantum Field Theory - Its status and its future
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.

Related papers:
Electromagnetism, local covariance, the Aharonov-Bohm effect and Gauss' law