Quantum back-action-evading measurement of motion in a negative mass reference frame

Area of Science:

• Quantum mechanics
• Quantum optics
• Optomechanics

Background:

• Continuous measurement of position causes quantum back-action (QBA), limiting motion sensing precision per the Heisenberg uncertainty principle.
• The standard quantum limit restricts the accuracy of position, velocity, and acceleration measurements.

Purpose of the Study:

• To demonstrate evasion of QBA on a macroscopic mechanical oscillator.
• To explore a hybrid quantum system combining mechanical and spin oscillators for enhanced sensing.

Main Methods:

• Utilized a hybrid system with a dielectric membrane mechanical oscillator and an atomic ensemble spin oscillator.
• Performed collective quantum measurement on the hybrid system using light.
• Configured the spin oscillator in negative-effective-mass and positive-effective-mass settings.

Main Results:

• Achieved QBA suppression of -1.8 decibels in the negative-mass setting.
• Observed QBA enhancement of 2.4 decibels in the positive-mass setting.
• Demonstrated evasion of standard quantum limit limitations.

Conclusions:

• Evasion of QBA in hybrid quantum systems opens new avenues for precision sensing beyond the standard quantum limit.
• This work facilitates entanglement generation and quantum communication between distant mechanical and spin systems.
• The developed system holds potential for advanced applications in force, motion, and gravity sensing.