Conditional Dynamics of Optomechanical Two-Tone Backaction-Evading Measurements

Area of Science:

• Quantum physics
• Optomechanics
• Quantum information science

Background:

• Backaction-evading measurements offer precision beyond zero-point uncertainty.
• These measurements are crucial for quantum metrology and quantum information processing.
• Existing models often rely on adiabatic and rotating-wave approximations.

Purpose of the Study:

• To derive an exact expression for the conditional state in a two-tone backaction-evading measurement.
• To explore quantum phenomena beyond standard approximations in optomechanical systems.
• To investigate entanglement in both single- and multi-mode optomechanical systems.

Main Methods:

• Derivation of an exact conditional state expression for two-tone measurements.
• Extensive numerical simulations to bypass the rotating-wave approximation.
• Analysis extended to multimode optomechanical systems (two mechanical, one cavity mode).

Main Results:

• Prediction of simultaneous conditional mechanical squeezing and intracavity squeezing.
• Demonstration of optomechanical entanglement in a single-mode system.
• Identification of conditional mechanical Einstein-Podolski-Rosen entanglement and tripartite entanglement in multimode systems.

Conclusions:

• The study provides a theoretical framework for advanced optomechanical measurements.
• Results highlight the potential for enhanced precision and entanglement generation.
• Findings are relevant for developing ultrasensitive sensors and measurement-based control in high-cooperativity systems.