AZE91: Enhancing QKD via Quantum Noise Suppression and Adaptive Basis Control

Quantum Key Distribution (QKD) provides secure communication through the principles of quantum mechanics. The E91 protocol using entangled photon pairs and Bell’s inequality has been extensively researched for its security advantage. Practical realization is, however hindered by environmental noise, channel losses and detector inefficiencies, constraining secure key rates and communication distances. This paper presents AZE91, an optimized version of E91 that includes novel noise reduction methods, such as Dynamical Decoupling (DD), Decoherence-Free Subspaces (DFS) and the Quantum Zeno Effect. Moreover, adaptive basis optimization adaptively adjusts measurement settings in real-world scenario to optimize the violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality a key element in determining quantum correlations. The protocol starts with the creation of a most entangled Bell state and uses a Werner state noise model to mimic actual time imperfections. Using DD and the Quantum Zeno Effect, AZE91 greatly minimizes the quantum bit error rate (QBER) and maximizes the CHSH parameter. Monte Carlo simulations show that although conventional E91 achieves a CHSH parameter close to 2.5 and a QBER of around 3.5%, AZE91 enhances these values to a CHSH parameter of around 2.7 and a QBER of around 2%. This enhancement results in a higher raw key rate and more security. The results indicate the capability of AZE91 to outperform conventional entanglement-based QKD systems and form a robust platform for experimental verification and further exploration.