Third-order exceptional line in a nitrogen-vacancy spin system
Abstract
The exceptional points (EPs) aroused from the non-Hermiticity bring rich phenomena, such as exceptional nodal topologies, unidirectional invisibility, single-mode lasing, sensitivity enhancement and energy harvesting. Isolated high-order EPs have been observed to exhibit richer topological characteristics and better performance in sensing over 2nd-order EPs. Recently, high-order EP geometries, such as lines or rings formed entirely by high order EPs, are predicted to provide richer phenomena and advantages over stand-alone high-order EPs. However, experimental exploration of high-order EP geometries is hitherto beyond reach due to the demand of more degrees of freedom in the Hamiltonian's parameter space or a higher level of symmetries. Here we report the observation of the third-order exceptional line (EL) at the atomic scale. By introducing multiple symmetries, the emergence of the third-order EL has been successfully realized with a single electron spin of nitrogen-vacancy center in diamond. Furthermore, the behaviors of the EP structure under different symmetries are systematically investigated. The symmetries are shown to play essential roles in the occurrence of high-order EPs and the related EP geometries. Our work opens a new avenue to explore high-order EP-related topological physics at the atomic scale and to the potential applications of high-order EPs in quantum technologies.
Cite
@article{arxiv.2401.09690,
title = {Third-order exceptional line in a nitrogen-vacancy spin system},
author = {Yang Wu and Yunhan Wang and Xiangyu Ye and Wenquan Liu and Zhibo Niu and Chang-Kui Duan and Ya Wang and Xing Rong and Jiangfeng Du},
journal= {arXiv preprint arXiv:2401.09690},
year = {2024}
}