Hierarchical Continuous-Wave Liquid-Crystal Quantum-Photonic Processor

Abstract

ocessor based on electrically addressable ferroelectric-nematic liquid-crystal (FNLC) nonlinear elements. The architecture combines continuous-wave spontaneous parametric down-conversion with shallow cascaded photon-generation modules, time-resolved heralding, parallel processing panels, and measurement-mediated electrical coupling between panels. Rather than increasing the depth of a single nonlinear cascade, scalability is achieved predominantly by increasing the number of independently operating modules and interconnected panels. Quantum correlations are generated locally within nonlinear modules, while detection outcomes from one part of the processor can be used by a classical controller to modify the voltages and hence the subsequent quantum-optical states generated in other parts. This event-driven organization allows probabilistically generated quantum resources to be selected and processed without requiring simultaneous successful generation throughout the entire device. Recent demonstrations of continuouswave SPDC, quasi-phase matching, and electrical control of entangled-photon generation in FNLCs provide the experimental basis for the proposed architecture. The key unresolved parameter is the probability of secondary single-photon-pumped down-conversion in an FNLC element. Its measurement provides a direct quantitative test of the feasibility of cascaded FNLC processing. The proposed system is therefore formulated as an adaptive quantum-photonic processor rather than a universal gate-based quantum computer, with coherent photonic interconnects and quantum storage representing possible future extensions.