2021/10/15 by J. Wang, Jiaxuan Wang, Debsuvra Mukhopadhyay +2
Mathematics · Physics and Astronomy · #Electronic engineering #Fisher information #Hermitian matrix #Laser linewidth #Mathematics #Nonlinear Photonic Systems #Parity (physics) #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Quantum #Quantum Mechanics and Non-Hermitian Physics #Quantum chaos and dynamical systems #Quantum mechanics #Sensitivity (control systems) #Statistical physics #Statistics #Theoretical physics #cond-mat.other #quant-ph
paper · pdf · doi:10.1103/physrevresearch.4.013131
6 pages, 1 figure
arxiv created 2021/10/15 · openalex publication_date 2022/02/18 · arxiv updated 2022/03/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The efficient sensing of weak environmental perturbations via special degeneracies called exceptional points in non-Hermitian systems has gained enormous traction in the last few decades. However, in contrast to the extensive literature on parity-time (PT) symmetric systems, the exotic hallmarks of anti-PT symmetric systems are only beginning to be realized now. Very recently, a characteristic resonance of vanishing linewidth in anti-PT symmetric systems was shown to exhibit tremendous sensitivity to intrinsic nonlinearities. Given the primacy of sensing in non-Hermitian systems, in general, and the immense topicality of anti-PT symmetry, we investigate the statistical bound to the measurement sensitivity for any arbitrary perturbation in a dissipatively coupled, anti-PT symmetric system. Using the framework of quantum Fisher information and the long-time solution to the full master equation, we analytically compute the Cramer-Rao bound for the system properties like the detunings and the couplings. As an illustrative example of this formulation, we inspect and reaffirm the role of a long-lived resonance in dissipatively interacting systems for sensing applications. \endabstract