Dissertation Title: Structures of Quantum Entangled neutron Beams
Abstract: In this thesis, we investigate entangled-probe scattering with neutrons. As neutrons have already been shown to be near-ideal probes of complex condensed matter systems, we extend the venerable field of neutron scattering to include mode-entangled neutrons that are intraparticle-entangled in their various degrees of freedom such as spin, path, energy, and orbital angular momentum. To produce such quantum-structured, entangled beams, we must develop and modify high-fidelity polarized neutron instrumentation as neutrons seem to mostly act semiclassically, making quantum control difficult (and quantum tomography mostly impossible). Two such examples discussed here are radio-frequency (rf) neutron spin flippers and magnetic Wollaston prisms (MWPs). We discuss experiments that use these devices for three primary purposes: 1) the investigation of the entanglement of quantum materials and search for novel scattering signatures, 2) quantum-enhanced sensing and metrology of conventional systems, and 3) the precision measurement of the fundamental and emergent physical properties of the neutron.
After the first introductory chapter which develops the formalism necessary to treat our neutron beams as fundamentally quantum objects, we discuss the instrumentation used to generate and manipulate entangled neutron beams in the second chapter. In the third chapter, we introduce angle-encoded radiography, which uses MWPs to enhance the resolution of traditional neutron radiography. The fourth chapter is devoted more broadly to neutron entanglement and the development of entangled scattering, and chapter five concentrates on the theory and experiment of spin-orbit entangled neutron beams with definite states of orbital angular momentum. Finally, chapter six discuss the measurement of the neutron Goos-Hänchen effect using entangled neutron reflectometry.
