Exceptional-Point Sensors Offer No Fundamental Signal-to-Noise Ratio Enhancement

Area of Science:

• Physics
• Quantum Mechanics
• Sensor Technology

Background:

• Exceptional-point (EP) sensors offer high sensitivity due to square-root resonant frequency bifurcation.
• A key debate exists regarding whether inherent system noise negates the sensitivity advantage of EP sensors.

Purpose of the Study:

• To resolve the debate on whether noise negates the sensitivity advantage of EP sensors.
• To investigate the potential of quantum-enhanced EP sensors.

Main Methods:

• Analysis of fundamental quantum and thermal noise in EP sensors, including self-excited (PT-symmetric) systems.
• Comparison of EP sensor performance against theoretical limits and technical noise.

Main Results:

• Fundamental quantum and thermal noise in EP sensors, particularly self-excited ones, negate the inherent sensitivity benefit.
• EP sensing schemes are only advantageous with quantum enhancement or when compared to technically limited sensors.
• Proposed quantum-enhanced EP sensor demonstrates a sensing advantage even under quantum or thermal noise limitations.

Conclusions:

• The fundamental sensitivity advantage of EP sensors is often negated by intrinsic noise.
• Practical applications of EP sensors are viable when compared to technically limited sensors.
• Quantum enhancement is crucial for realizing a true sensing advantage in EP sensors under fundamental noise conditions.