Quantum Information Enabled Neutron Interferometry
Loading...
Date
2017-06-12
Authors
Nsofini, Joachim
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Neutron interferometry with its ability to encode and extract information provides a test
bed for quantum mechanics and precise measurement of physical quantities of significant
importance in physics. However, this significant key investigative technique is weakened
by its very fragile nature; neutron interferometry has proven to be highly sensitive to
environmental noise.
Once brought to its optimal state, the use of neutron interferometry enabled with
quantum information, represents a milestone. Indeed a realization of high-quality neutron
interferometry could pave a way to probe materials research such as probing properties
water in proteins and topological materials. Thus understanding and solving the sensitivity
of neutron interferometers to noise is a key step toward possible applications. This is the
core of the work done in this Thesis.
We incorporated two theoretical techniques developed for quantum information sciences
into the construction of a new polarized neutron interferometry beam line: The technique
of quantum error correction and the technique of open quantum system. One focus of this
work is to report on the design, the construction as well as the characteristic features of
this beamline.
This thesis involves experimental data, showing how the neutron beam intensity at the
exit of a three-blade neutron interferometer can be controlled by the interferometer blades
thickness. Secondly, is also presents an alternative and simplified quantum information
approach to dynamical diffraction, based on repeated application of a coherent beam-
splitting unitary at coarse-grained lattice sites. Demanding translational invariance added
to a computationally tractable number of sites in the coarse-graining reproduced many
results typical of standard dynamical diffraction theory and experiments. Building on that,
a proposal for a new five-blade neutron interferometer is presented and its robustness to
noise, resulting from dynamical diffraction together with low-frequency external mechanical
vibration is discussed.
Steps ahead in our work, neutron interferometry may be improved as well as adapted to
more applications by incorporating the spin and orbital degrees of freedom to a path-based
ivinterferometer. In this concern, we propose a method to prepare the spin-orbit state by
passing a polarized neutron beam through a quadrupole magnetic field. Initially designed
for a beam the size of a coherent length, we extend this method to work for spatially
displaced beams by using linear magnetic gradients.
Description
Keywords
Quantum information, quantum physics, neutron interferometry, quantum coherence, orbital angular momentum, dynamical diffraction, quantum sensors