Large single-atom cooperativity in quantum systems is important for quantum information processing. Here, we propose to exponentially enhance the single-atom cooperativity parameter by exploiting the strongly localized effect of modes in cavity quantum electrodynamics (QED) systems. By increasing the wing width of a cavity with special geometry symmetry, the interference property allows us to exponentially improves the quality factor Q without altering the mode volume V for cavities supporting subwavelength light modes. This effectively overcomes the trade-off between Q and V in conventional subwavelength Fabry-Perot cavities. Consequently, we demonstrate the occurrence of ultra-long vacuum Rabi oscillations and the generation of strong photon blockade by enhancing the single-atom cooperativity parameter. This work offers a promising approach for advancing coherent manipulation and holds significant potential for applications in establishing longer-distance quantum communication networks, enhancing the precision and stability of quantum sensors, and improving the efficiency of quantum algorithms.
@article{arxiv.2509.04739,
title = {Cavity QED based on strongly localized modes: exponentially enhancing single-atom cooperativity},
author = {Qian Bin and Ying Wu and Jin-Hua Gao and Aixi Chen and Franco Nori and Xin-You Lü},
journal= {arXiv preprint arXiv:2509.04739},
year = {2025}
}