The effects of geometry and patch potentials on Casimir force measurements

dc.contributor.advisorMunday, Jeremy N.en_US
dc.contributor.authorGarrett, Joseph L.en_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.description.abstractElectromagnetic fluctuations of the quantum vacuum cause an attractive force between surfaces, called the Casimir force. In this dissertation, the first Casimir force measurements between two gold-coated spheres are presented. The proximity force approximation (PFA) is typically used to compare experiment to theory, but it is known to deviate from the exact calculation far from the surface. Bounds are put on the size of possible deviations from the PFA by combining several sphere-sphere and sphere-plate measurements. Electrostatic patch potentials have been postulated as a possible source of error since the first Casimir force measurements sixty years ago. Over the past decade, several theoretical models have been developed to characterize how the patch potentials contribute an additional force to the measurements. In this dissertation, Kelvin probe force microscopy (KPFM) is used to determine the effect of patch potentials on both the sphere and the plate. Patch potentials are indeed present on both surfaces, but the force calculated from the patch potentials is found to be much less than the measured force. In order to better understand how KPFM resolves patch potentials, the artifacts and sensitivities of several different KPFM implementations are tested and characterized. In addition, we introduce a new technique, called tunable spatial resolution (TSR) KPFM, to control resolution by altering the power-law separation dependence of the KPFM signal.en_US
dc.subject.pqcontrolledMaterials Scienceen_US
dc.subject.pquncontrolledAtomic force microscopyen_US
dc.subject.pquncontrolledCasimir forceen_US
dc.subject.pquncontrolledKelvin probe force microscopyen_US
dc.subject.pquncontrolledPatch potentialsen_US
dc.subject.pquncontrolledvan der Waalsen_US
dc.titleThe effects of geometry and patch potentials on Casimir force measurementsen_US


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