Stewart, Andrew2015-12-100950-0340http://hdl.handle.net/1885/69456It is shown that when the gauge-invariant Bohr-Rosenfeld commutators of the free electromagnetic field are applied to the expressions for the linear and angular momentum of the electromagnetic field interpreted as operators then, in the absence of electric and magnetic charge densities, these operators satisfy the canonical commutation relations for momentum and angular momentum. This confirms their validity as operators that can be used in quantum mechanical calculations of angular momentum.Keywords: Commutation relation; Quantisation; quantum electrodynamics; Quantum-mechanical calculation; Electric commutators; Electrodynamics; Electromagnetic fields; Quantum electronics; Angular momentum angular momentum; light; quantisation; quantum electrodynamics201110.1080/09500340.2011.5717972016-02-24