Our celebration of Dr. Shufan Lu's successful doctoral dissertation defense, with her supervisor, Dr. W. Michael Snow.
Dissertation Title: Quantum Description of Mode-Entangled Single Neutron Interferometry and Decoherence Analysis of Two-State Neutron Superpositions with Absorption
Abstract: Neutron is a subatomic particle. It has a mass, a spin of 1/2, a magnetic moment and electrical neutrality. Those properties make slow neutrons ideal probes for condensed matter and fundamental physics research. Typically, neutrons are scattered from sample materials when they are used to probe physics phenomena. By measuring the scattered neutron patterns, information about the internal structures and dynamics of the material can be analyzed.
In this thesis, we introduce a multimode-entangled neutron beam as an unconventional quantum probe. With the use of entanglement devices, individual neutrons can be entangled in spin, trajectory and energy. We develop an operator-based description of two entanglement devices, the magnetic Wollaston prisms and the radio-frequency neutron spin flippers. We describe operationally how a multimode-entangled single-neutron state evolves in the interferometer and how it is analyzed after measurement by the detector. This is the first step in developing a scattering theory for entangled neutron scattering interpretation.
To ensure the accuracy and reliability of neutron scattering measurements, it is important to estimate the decoherence of neutron probes. In this work, we derive the expected decoherence rate upon mirror reflection for a two-state neutron system. We also apply this calculation to the case of a neutron-antineutron oscillation system and show that the decoherence rate per bounce for neutron-antineutron oscillation can be small enough over a wide range of elements, enabling the use of mirrors in future neutron-antineutron oscillation experiments.