Quantum Information Approach to Dynamical Diffraction Theory

TL;DR

This paper introduces a quantum information-based model for dynamical diffraction in crystals, using coherent beam splitting unitaries to accurately predict diffraction phenomena across various crystal thickness regimes.

Contribution

It presents a novel quantum information approach that simplifies and unifies the modeling of dynamical diffraction in perfect crystals, applicable to different crystal thicknesses.

Findings

Reproduces key results of traditional dynamical diffraction theory

Predicts neutron interferometer output profiles and interference patterns

Applicable across thick, thin, and intermediate crystal regimes

Abstract

We present a simplified model for dynamical diffraction of particles through a periodic thick perfect crystal based on repeated application of a coherent beam splitting unitary at coarse-grained lattice sites. By demanding translational invariance and a computationally tractable number of sites in the coarse-graining we show how this approach reproduces many results typical of dynamical diffraction theory and experiments. This approach has the benefit of being applicable in the thick, thin, and intermediate crystal regimes. The method is applied to a three-blade neutron interferometer to predict the output beam profiles, interference patterns, and contrast variation.