Dynamic Quantum Gate Based on Controllable Chiral Liquid Crystal Nanostructure.

Abstract

The photonic quantum system, as a prominent candidate for quantum information processing, possesses inherent advantages of room-temperature operation, a long coherence time, and a large encoding capacity. However, a conventional photonic quantum gate is usually limited by its bulky volume, complicated protocols, and fixed functions. Here, we find that chiral liquid crystal (CLC) nanostructure can offer a feasible platform for a dynamic photonic quantum gate. Tuning a uniformly self-assembled nanostructure enables a full rotation of the Bloch sphere within the short wavelength circular regime of the CLC, facilitating efficient implementation of the identity gate, S gate, and Pauli-Z gate. Furthermore, such a CLC gate enables dynamic control over the transformation between polarization-entangled states. It is utilized to control hybrid entanglement between the polarization and orbital angular momentum, linking the Poincaré sphere to the higher-order Poincaré sphere. This work demonstrates the potential of soft-matter CLC nanostructure to serve as a versatile platform in the photonic quantum system.