Projects per year
Abstract
In the absence of charges, Maxwell's equations are highly symmetrical. In particular, they place the electric and magnetic fields on equal footing. In light of this electricmagnetic symmetry, we introduce a variational description of the free electromagnetic field that is based upon the acknowledgement of both electric and magnetic potentials. We use our description, together with Noether's theorem, to demonstrate that electricmagnetic symmetry is, in essence, an expression of the conservation of optical helicity. The symmetry associated with the conservation of Lipkin's zilches is also identified. We conclude by considering, with care, the subtle separation of the rotation and boost angular momenta of the field into their 'spin' and 'orbital' contributions.
Original language  English 

Article number  123019 
Number of pages  27 
Journal  New Journal of Physics 
Volume  14 
DOIs  
Publication status  Published  12 Dec 2012 
Keywords
 electromagnetism
 particle physics
 Maxwell equations
 electric–magnetic symmetry
 Lipkin’s zilches
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Dive into the research topics of 'Electricmagnetic symmetry and Noether's theorem'. Together they form a unique fingerprint.Projects
 2 Finished

Challenges in Orbital Angular Momentum
Barnett, S.
EPSRC (Engineering and Physical Sciences Research Council)
1/01/11 → 30/11/14
Project: Research
