Reinventing Neutron Interferometry Using Quantum Information Theory

Neutron Interferometry is a very versatile means of characterizing soft matter and magnetic materials, as well as being an excellent example of quantum coherence.  It is also notoriously difficult to construct a neutron interferometry so as to have a high and stable contrast.  We have borrowed concepts from quantum information processing (quantum error correction) to build a new geometry for neutron interferometry that is more robust and much more compact than the current designs.  Based on this design we can implement small, special purpose interferometers with greater sensitivity and for new applications.  I will describe the general idea behind quantum error correction and show how this enables robust neutron interferometry.  I will also sketch a new interferometry geometry that enables the direct measurement of spatial correlations of the coherent and magnetic neutron cross-sections.