Magnetic monopole

Summary

A magnetic monopole is a hypothetical particle that carries a net magnetic charge. It is a source of the magnetic field in the way an electric charge is a source of the electric field. Ordinary Maxwell's equations exclude it through Gauss's law for magnetism, and no monopole has been observed. Dirac showed that the existence of a single monopole would force all electric charges to be integer multiples of a basic charge. In geometry the field of a monopole is described by a connection on a nontrivial circle bundle over the sphere. Monopoles of gauge theories are a major topic in mathematics.