Light & Matter Seminar: Professor Martin McCall - Augmenting Maxwell

Join Professor Martin McCall from Imperial College London for a Light & Matter Seminar entitled 'Augmenting Maxwell' 

Abstract: 

Here, at the very institution where Maxwell developed his unified theory of electricity, magnetism and light, I dare to challenge the foundations of his beautiful theory. His equations, commemorated in the plaque you have on display at KCL, are incomplete as stated and, I would argue, do not recognise the distinction between the fundamental fields E and B, and the excitation fields D and H. Traditionally, the extra information linking these fields, required to solve Maxwell’s equations, is provided through so-called constitutive relations. These, however, are model dependent and not gauge invariant. I will lay out an alternative scheme that replaces the inhomogeneous Maxwell equations and the constitutive relations with ‘first order operators’ acting directly on the fundamental fields E and B. As well as reproducing conventional macroscopic electromagnetic theory in the appropriate limit, we show that this method admits a richer gamut of possibilities of meta-media than does the conventional approach. In particular, we identify novel axion-like terms and discuss how these might be experimentally realized. Tracing our approach back to vacuum, we admit the possibility of an axion-like term augmenting the conventional vacuum constitutive relations. We show that it has a topological character, one that can be exploited by manipulation of the background space-time manifold. In a simple model setting, we show that a careful examination of the mathematical basis of Stokes’ theorem, leads to a severance of the link between local and global charge conservation.

How to join:

Those external to King's should email this address to gain access to the building.