Application of quantum state tomography to experimental analysis of entanglement in quantum optical circuits
Vladimir Valer'evich Nikulin, Rushui Fang, John E. Malowicki, Vijit Bedi · 2020
This paper describes high-performance optical circuits operating on hyper-entangled quantum states. The concept is based on correlated photon pairs generated in such a way that their polarization, frequency or propagation paths are entangled and can be used to support quantum encryption protocols. Detection and processing of such signals requires hyper-spectral optical circuits capable of responding to non-classical features of light. Processing capabilities of these quantum circuits are straight-forward in theory, but physical implementation can still present a challenge for integrity of the quantum states. In this paper, we address experimental verification of entanglement characteristics at each step of building the quantum optical circuits and present a formal quantitative approach based on the quantum state tomography.