Fundamental Sensitivity Limits for Non-Hermitian Quantum Sensors

Area of Science:

• Quantum Information Science
• Quantum Metrology
• Non-Hermitian Physics

Background:

• Non-Hermitian systems are increasingly explored for novel quantum sensing applications.
• Understanding the fundamental performance limits of these sensors is crucial for their practical development.

Purpose of the Study:

• To determine the fundamental sensitivity limits of non-Hermitian sensors using quantum information theory.
• To compare the performance of non-Hermitian sensors against their Hermitian counterparts.

Main Methods:

• Theoretical analysis based on quantum information.
• Scrutiny of two specific non-Hermitian sensing proposals implemented in full quantum systems.

Main Results:

• Non-Hermitian sensors do not surpass the sensitivity of Hermitian sensors.
• The quantum information about the parameter is invariant, limiting sensitivity gains.
• Experimental proposals align with theoretical predictions for non-Hermitian sensor sensitivity.

Conclusions:

• A comprehensive, model-independent framework for non-Hermitian quantum sensor limits is established.
• The study bridges the gap between non-Hermitian physics and quantum metrology.
• Non-Hermitian sensors do not provide an advantage in sensitivity over Hermitian ones.