A botanical catalogue of magnetic singularities
Class: Theoretical Fundamental
First described by P.A.M. Dirac (1931). A singular magnetic charge whose existence would explain the quantization of electric charge. Predicted mass varies by theoretical framework. No confirmed specimen collected.
Class: Topological Defect
A massive monopole arising from spontaneous symmetry breaking in grand unified theories. Estimated mass ~10^16 GeV. Formed in the phase transitions of the early universe. Specimen predicted but never isolated.
Class: Observational Anomaly
Recorded February 14, 1982 at Stanford. A single SQUID magnetometer registered exactly one Dirac quantum of magnetic charge. The only candidate detection event. Never replicated. Status: unconfirmed.
Class: Quasiparticle
Observed in spin ice materials (Dy2Ti2O7, Ho2Ti2O7). Magnetic excitations that behave exactly as Dirac monopoles within the crystal lattice. Successfully isolated in laboratory conditions since 2009.
Class: Mathematical Construct
An infinitely thin solenoid extending from the monopole to infinity. Required to reconcile monopole existence with vector potential formalism. Unobservable by construction. A mathematical ghost supporting a physical prediction.
Class: Fundamental Constant
g = nhc/2e. The quantization condition linking magnetic and electric charge. If monopoles exist, their magnetic charge must be an integer multiple of this quantum. The mathematical seed from which all monopole physics grows.