PT-symmetric feedback induced linewidth narrowing
Abstract
Narrow linewidth is a long-pursuing goal in precision measurement and sensing. We propose a parity-time (PT )-symmetric feedback method to narrow the linewidths of resonance systems. By using a quadrature measurement-feedback loop, we transform a dissipative resonance system into a PT-symmetric system. Unlike the conventional PT-symmetric systems which typically require two or more modes, here the PT-symmetric feedback system contains only a single resonance mode, which greatly extends the scope of applications. The method enables remarkable linewidth narrowing and enhancement of measurement sensitivity. We illustrate the concept in a thermal ensemble of atoms, achieving a 48-fold narrowing of the magnetic resonance linewidth. By applying the method in magnetometry, we realize a 22-times improvement of the measurement sensitivity. This work opens the avenue for studying non-Hermitian physics and high-precision measurements in resonance systems with feedback.
Cite
@article{arxiv.2304.07475,
title = {PT-symmetric feedback induced linewidth narrowing},
author = {Yuanjiang Tang and Chao Liang and Xin Wen and Weipeng Li and An-Ning Xu and Yong-Chun Liu},
journal= {arXiv preprint arXiv:2304.07475},
year = {2023}
}
Comments
5 pages, 5 figures