Qubit–qubit quantum coherence mediated by an epsilon-near-zero waveguide

Abstract

Abstract Quantum coherence, as a more general quantum resource compared to quantum entanglement, has increasingly attracted much attention in recent years. Establishing stable quantum coherence is crucial for implementing reliable quantum information tasks. In this study, we propose an scheme to generate stable quantum coherence of two qubits via an ENZ waveguide. We find that employing Si$_3$N$_4$ rather than SiO$_2$ results in stronger qubit-qubit coupling and maximal quantum coherence in certain range. We derive analytical expressions for both quantum coherence and quantum entanglement, allowing for direct comparison within a unified framework. To achieve stable quantum coherence, classical field driving is introduced. We find that stable coherence is much larger and easier mediated than that of stable entanglement. Our work contributes to the creation of new stable quantum resource via an ENZ waveguide.