Optimal Phase-Insensitive Force Sensing with Non-Gaussian States

Area of Science:

• Quantum physics
• Quantum metrology
• Quantum sensing

Background:

• Quantum metrology offers precision near fundamental limits.
• Continuous quantum modes enhance sensitivity with occupation number.
• Quantum non-Gaussian states improve metrology and can be tailored.

Purpose of the Study:

• Investigate a force-sensing scheme using randomized phase-space displacement.
• Infer unknown force strength via excitation-number-resolving measurements.
• Identify optimal quantum states for force sensing under realistic conditions.

Main Methods:

• Utilized N-spaced states for sensing bound approximation.
• Analyzed decoherence resilience of Gaussian vs. non-Gaussian states.
• Employed quantum optimal control in a spin-boson system with a decoherence-aware reward functional.

Main Results:

• N-spaced states approach achievable sensing bounds.
• Non-Gaussian states demonstrate superior resilience to decoherence.
• Number-squeezed Schrödinger cat states maximize force sensitivity under lossy dynamics and control limitations.

Conclusions:

• Identified number-squeezed Schrödinger cat states as optimal for force sensing.
• Demonstrated a pathway for enhanced force sensing in diverse quantum systems.
• Highlighted the importance of tailored quantum states for practical quantum sensing applications.