Full-Counting Statistics and Quantum Information of Dispersive Readout with a Squeezed Environment

Area of Science:

• Quantum optics
• Quantum information science
• Quantum measurement

Background:

• Dispersive readout is crucial for quantum technology.
• Existing methods face limitations with nonlinearities and complex dynamics.

Purpose of the Study:

• To develop a new theoretical framework for dispersive readout.
• To analyze measurement information using a time-reversal-symmetric squeezed vacuum probe.
• To address non-unitary dynamics in quantum systems.

Main Methods:

• Developed a full-counting-statistics framework for dispersive readout.
• Employed a generalized mean-field approach for non-unitary dynamics.
• Calculated arbitrary-order cumulants of the photonic distribution.

Main Results:

• The Fisher information shows exponential dependence on the squeezing parameter.
• The method is robust against residual nonlinearity.
• Achieved results approaching the quantum Fisher information limit.

Conclusions:

• Introduced a streamlined and efficient framework for continuous quantum measurements.
• The framework is suitable for nonlinear systems and widespread adoption in quantum technologies.
• Offers a powerful tool for advancing quantum readout protocols.