Measurement of Motion beyond the Quantum Limit by Transient Amplification

Area of Science:

• Quantum Mechanics
• Optomechanics
• Nanotechnology

Background:

• Precise measurement of mechanical motion is crucial for quantum technologies.
• Existing methods often introduce significant noise, limiting sensitivity.
• Quantum limits on measurement precision pose a challenge.

Purpose of the Study:

• To develop a novel method for nearly noiseless pulsed measurement of mechanical motion.
• To achieve measurement sensitivity below the standard quantum limit for certain parameters.
• To demonstrate the capability of resolving quantum states of mechanical oscillators.

Main Methods:

• Utilizing simultaneous but unequal electromechanical amplification and cooling processes.
• Employing transient electromechanical amplification (TEA) for pulsed measurements.
• Monitoring a single motional quadrature of a mechanical oscillator.

Main Results:

• Achieved a total added noise of -8.5±2.0 dB relative to the zero-point motion.
• Demonstrated the ability to resolve fine structure in the phase space of a mechanical oscillator.
• Directly observed a squeezed variance 2.8±0.3 dB below the oscillator's zero-point motion without noise subtraction.

Conclusions:

• The developed TEA technique offers a pathway to near-noiseless quantum measurements.
• This method allows for direct observation and characterization of quantum states of motion.
• The technique has potential applications in quantum sensing and information processing.