Part I. Energy loss of magnetic monopoles. Part II. The functional integral measure in quantum gravity

Part I. The energy loss of slowly moving magnetic monopoles in atomic Hydrogen and Helium is investigated. It is found that magnetic monopoles can cause large shifts in the energy levels of atoms, thus providing a mechanism for excitation of the atoms. Probabilities for such excitation processes in atomic Hydrogen and Helium are computed. It is suggested that the Helium calculations could be used as the basis for a realistic detector of magnetic monopoles. Part II. The problem of the measure in functional integral formulations of quantum gravity is studied. Perturbation theory about a Minkowski space background is formulated, and the corresponding Feynman rules are derived for pure Einstein gravity in a covariant gauge. Peturbative contributions to the induced cosmological constant are investigated using these Feynman rules