Strong thermomechanical squeezing via weak measurement.

Area of Science:

• Quantum mechanics
• Nanotechnology
• Control systems engineering

Background:

• Parametric squeezing is crucial for enhancing mechanical oscillator precision.
• Existing methods face limitations, such as the 3 dB steady-state squeezing limit.
• Atomic force microscopy (AFM) requires highly localized mechanical components.

Purpose of the Study:

• To experimentally exceed the 3 dB limit for steady-state parametric squeezing of mechanical oscillators.
• To enhance the localization precision of an AFM cantilever.
• To explore the application of nonlinear processes in control systems.

Main Methods:

• Utilized a detuned parametric drive to manipulate a mechanical oscillator.
• Employed optimal estimation techniques for precise cantilever localization.
• Conducted experiments on low-temperature, high-frequency oscillators.

Main Results:

• Achieved steady-state parametric squeezing surpassing the 3 dB limit, reaching up to 6.2 dB enhancement in position quadrature.
• Demonstrated improved localization of an AFM cantilever beyond measurement precision.
• Showcased that squeezing is primarily limited by the oscillator's Q factor.

Conclusions:

• The developed technique overcomes established limits in nonlinear processes via control systems engineering.
• Mechanical nonlinearities are valuable for advanced control applications.
• This method offers a path towards robust quantum squeezing below zero-point motion.