Experimental Investigation of Quantum PT-Enhanced Sensor

Area of Science:

• Quantum mechanics
• Non-Hermitian physics
• Complex systems

Background:

• Parity-time (PT)-symmetric theory extends quantum mechanics into complex domains.
• Classical PT-symmetric systems exhibit unique phenomena like unidirectional transport and enhanced sensing.
• Transitioning PT-symmetry to the quantum regime has been challenging due to difficulties in constructing broken PT-symmetric systems.

Purpose of the Study:

• To construct a quantum PT-symmetric system capable of transitioning between unbroken and broken regions.
• To experimentally realize and investigate a quantum version of PT-enhanced sensors.
• To explore the potential for directional perturbation detection in quantum systems.

Main Methods:

• Development of a quantum PT-symmetric system assisted by weak measurement.
• Direct measurement of the full energy spectrum (real and imaginary parts) using weak values.
• Experimental translation and analysis of PT-enhanced sensors in the quantum regime.

Main Results:

• Successfully constructed a quantum PT-symmetric system that can effectively transit to a broken region.
• Achieved an 8.856-fold enhancement in sensitivity for a quantum PT-enhanced sensor compared to conventional Hermitian sensors.
• Demonstrated the ability to derive information about the direction of perturbations by detecting real and imaginary parts of energy splitting.

Conclusions:

• The study successfully bridges classical PT-symmetric phenomena to the quantum realm.
• The developed quantum PT-enhanced sensor offers significant advantages in sensitivity and directional sensing.
• This work provides a foundation for studying general exceptional points in quantum non-Hermitian systems.