A strange monopole observed in diamond: When string theory inspires quantum simulation

Theoretical physicists routinely introduce fictitious particles and fields in their calculations, in view of completing a theory or simply to make it more elegant. A striking example concerns the magnetic monopole imagined by Dirac in 1931: a point-like source of magnetic field, which is absent in classical electromagnetism. While the Dirac monopole was never observed in nature, it appears artificially in various physical settings, in particular, in the solid state.