Squeezed Superradiance Enables Robust Entanglement-Enhanced Metrology Even with Highly Imperfect Readout

Area of Science:

• Quantum physics
• Quantum metrology
• Quantum sensing

Background:

• Quantum metrology aims to surpass the standard quantum limit (SQL) using entangled states.
• Technical noise from imperfect sensor readout often limits sensitivity in these protocols.
• Existing amplification strategies are sensitive to dissipation, requiring high single-spin cooperativity.

Purpose of the Study:

• To develop a quantum metrology protocol resilient to readout noise and dissipation.
• To enable enhanced sensing beyond the SQL using entangled spin states.
• To reduce the stringent cooperativity requirements of previous methods.

Main Methods:

• A novel dissipative protocol combining amplification and squeezed fluctuations.
• Utilizing entangled states of large spin ensembles.
• Leveraging collective cooperativity for resilience against dissipation.

Main Results:

• The protocol enables sensing beyond the SQL despite significant readout noise.
• Demonstrated strong resilience against single-spin dissipation.
• Requires only large collective cooperativity, a less stringent condition.

Conclusions:

• The proposed protocol significantly advances quantum sensing capabilities.
• Offers a practical approach for achieving high-precision measurements in realistic noisy environments.
• Opens new avenues for quantum metrology applications.