Testing the mass-proportional CSL model, that describes quantum-mechanical wave function collapse, by measuring a small offset in energy due to that same collapse, requires ultra-low temperatures....Show moreTesting the mass-proportional CSL model, that describes quantum-mechanical wave function collapse, by measuring a small offset in energy due to that same collapse, requires ultra-low temperatures. These temperatures can be reached, using adiabatic nuclear demagnetization as a refrigeration method. To obtain the lowest temperature possible and to do so for a long time, dissipation has to be minimized. Theoretical work in this thesis provides a way to decrease dissipation through an optimized demagnetization ramp, resulting in a final magnetic field of 5 mT and a field ramp rate of 0.5 mT/s. Experimentally, a decrease in dissipation is found by comparing demagnetization ramps with and without an LCR circuit. The ramp with such a circuit has approximately 2.5 times less dissipation. Also discussed in this thesis is SQUID thermometry, a reliable way of measuring the temperature at ultra-low temperatures. An analysis method is presented to reduce the influence of mechanical interference when determining the temperature.Show less
In this work, we investigate methods to determine the average length for cotunneling in self-assembled gold nanoparticle arrays spaced with alkanethiols. Cotunneling currents can be as low as 10 fA...Show moreIn this work, we investigate methods to determine the average length for cotunneling in self-assembled gold nanoparticle arrays spaced with alkanethiols. Cotunneling currents can be as low as 10 fA, requiring the development of robust measurement techniques to lower the noise floor. We present a comparison of different methods for finding the effective cotunneling length N. Preliminary findings on a variety of arrays indicate the onset of the cotunneling regime, but that there is no distinction in N between choice of alkanethiol in the array.Show less
