Narrow Results

In this paper, we investigate the dynamics of quantum memory-assisted entropic uncertainty, uncertainty-induced nonlocality and log-negativity entanglement of two nitrogen-vacancy centers (NVC). In particular, we are interested in analyzing two nitrogen-vacancy centered qubits coupled with two coherent nanocavities. We consider two different configurations of NVC qubits: when the qubits are prepared initially in separable and maximally entangled states. We demonstrate that coherent nanocavities can be successfully used to generate nonlocality and entanglement in the two NVC qubits while suppressing the associated entropic uncertainty. When the system is considered initially in separable two-NVC qubits, we show that the coupled coherent nanocavities successfully generate nonlocality and entanglement while avoiding the associated entropic uncertainty. The parameter’s adjustment determines the degree of entanglement, non-locality generation, and preservation. In comparison, we find entanglement more vulnerable to the decoherence and entropic uncertainty action between the two NVC qubits and nanocavities than the uncertainty-induced nonlocality. Furthermore, the NVC-qubits coupled with two coherent nanocavities promote entanglement’s sudden birth and death phenomena. This study contributes to the quantum mechanical protocols requiring the robust practical generation of entanglement and nonlocality as well as the related information preservation for the increased efficiency of quantum devices.

This paper presents a review on the selected highlights of highly-functional devices in two-dimensional photonic crystals slab structure. By introducing artificial defects in the photonic crystals (that is, defect engineering), novel photonic devices of line-defect waveguides and point-defect nanocavity are demonstrated. For more efficient manipulation of photons, the fundamentals of heterostructure photonic crystals are also reviewed. Heterostructures consist of multiple photonic crystals with different lattice-constants and they provide further high-functionalities such as multiple wavelength operation while maintaining optimized performance and the enhancement of photon manipulation efficiency. Because of the importance of high quality (Q) nanocavity for realization of nanophotonic devices, we also review the design rule of high Q nanocavities and present recent experiments on nanocavities with Q factors in excess of one million (~ 1.2 × 10⁶). The progress of defect engineering and heterostructure in two-dimensional photonic crystals slab structure will accelerate development in ultrasmall photonic chips, cavity quantum electrodynamics, optical sensors, etc.