Phys. Rev. Lett. 131, 103602 (2023)
Non-Hermitian Waveguide Cavity QED with Tunable Atomic Mirrors
Wei Nie1,*, Tao Shi2,3, Yu-xi Liu4, and Franco Nori5,6,7
1 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300350, China
2 Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190, China
3 CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
4 School of Integrated Circuits, Tsinghua University, Beijing 100084, China
5 Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wakoshi, Saitama 351-0198, Japan
6 Center for Quantum Computing, RIKEN, Wakoshi, Saitama 351-0198, Japan
7 Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
* weinie@tju.edu.cn
Abstract
Optical mirrors determine cavity properties by means of light reflection. Imperfect reflection gives rise to open cavities with photon loss. We study an open cavity made of atom-dimer mirrors with a tunable reflection spectrum. We find that the atomic cavity shows anti-PT symmetry. The anti-PT phase transition controlled by atomic couplings in mirrors indicates the emergence of two degenerate cavity supermodes. Interestingly, a threshold of mirror reflection is identified for realizing strong coherent cavity-atom coupling. This reflection threshold reveals the criterion of atomic mirrors to produce a good cavity. Moreover, cavity quantum electrodynamics with a probe atom shows mirror-tuned properties, including reflection-dependent polaritons formed by the cavity and probe atom. Our Letter presents a non-Hermitian theory of an anti-PT atomic cavity, which may have applications in quantum optics and quantum computation.
