Magnetic Resonance Force Microscopy and the spin bath : towards single-spin massive-resonator entanglement and the spoiling influence of the spin bath

There are many interpretations of quantum mechanics, and ultimately experiments are needed to verify or falsify these interpretations. In this thesis we work towards an experiment that should make the study of the existence of gravitational-induced collapse of the wave function feasible. We propose to use a Magnetic Resonance Force Microscope where we let the magnetic tip interact with a controlled Nitrogen-Vacancy center to study the superposition of the tip’s position (Ch.1 and Ch. 5). We have shown theoretically (Ch. 2) and experimentally (Ch.3) how spins on the surface and in the bulk can change the resonance frequency of the resonator and increase the dissipation. Using this theory we have measured the bulk impurity and surface spin density of diamond and performed local spin resonance on the bulk spins (Ch. 4). An important part of this thesis forms the partly new techniques and instrumentation that this experiment needs (Ch. 6). One of these techniques led to the study of the tip-sample capacitance in general SPM-applications which can be used to do fast pre-approaches and in-situ tip characterizations (Ch. 7).