CLASSICAL MONOPOLES - NEWTON, NUT SPACE, GRAVOMAGNETIC LENSING, AND ATOMIC SPECTRA

This article reviews the dynamics and observational signatures of part icles interacting with monopoles, beginning with a scholium in Newton' s Principia. The orbits of particles in the field of a gravomagnetic m onopole, the gravitational analog of a magnetic monopole, lie on cones ; when the cones are slit open and flattened, the orbits are the ellip ses and hyperbolas that one would have obtained without the gravomagne tic monopole. The more complex problem of a charged, spinning sphere i n the held of a magnetic monopole is then discussed. The quantum-mecha nical generalization of this latter problem is that of monopolar hydro gen. Previous work on monopolar hydrogen is reviewed and details of th e predicted spectrum are given. Protons around uncharged monopoles hav e a bound continuum. Around charged ones, electrons have levels and de caying resonances, so magnetic monopoles can grow in mass by swallowin g both electrons and protons. In general relativity, the spacetime pro duced by a gravomagnetic monopole is NUT space, named for Newman, Tamb orino, and Unti (1963). This space has a nonspherical metric, even tho ugh a mass with a gravomagnetic monopole is spherically symmetric. All geodesics in NUT space lie on cones, and this result is used to discu ss the gravitational lensing by bodies with gravomagnetic monopoles.