Quantum Fisher information perspective on sensing in anti-PT symmetric systems

The efficient sensing of weak environmental perturbations via special degeneracies called exceptional points in non-Hermitian systems has attracted enormous attention the last few decades. However, contrast to extensive literature on parity-time (PT) symmetric systems, exotic hallmarks anti-PT are only beginning be realized now. Very recently, a characteristic resonance vanishing linewidth was shown exhibit tremendous sensitivity intrinsic nonlinearities. Given primacy general, and immense topicality symmetry, we investigate statistical bound measurement for any arbitrary perturbation dissipatively coupled, system. Using framework quantum Fisher information long-time solution full master equation, analytically compute Cram\'er-Rao system properties such as detunings couplings. As an illustrative example this formulation, inspect reaffirm role long-lived interacting applications.