Challenging the limits of mechanical quantum metrology

Introduction

Nano- and micromechanical resonators, with their high coherence and low mass, serve as extremely good sensors of small forces and particles. They are especially powerful in combination with optical laser fields, which can measure mechanical motion down to the level where quantum mechanics is needed to describe it.

Limitations of Current Technology

The performance of mechanical quantum sensors, and in fact our ability to measure their displacement, is however limited by fundamental concepts:

1. Heisenberg’s Uncertainty Principle: This principle dictates the smallest vibration that can be resolved.
2. Time-Reversal Symmetry: This bounds the measurement rate of a sensor.

Project Goals

In this project, I challenge both limits – evading them by making nanomechanical resonators interact strongly with temporally controlled and nano-confined light fields.

Experimental Proposals

The experiments I propose will:

• Project a macroscopic mechanical object in a pure quantum state through the mere act of performing a strong measurement.
• Aim to show that such measurements can entangle the object’s internal degrees of freedom.
• Be used to boost metrology performance.

Enhancing Sensitivity

By breaking time-reversal symmetry through optical control, I seek to enhance the sensitivity of mechanical force sensors. I will investigate whether the measurement interaction can be employed to:

• Coherently convert optical to mechanical states.
• Manipulate optical signals down to the single-photon level.

Expected Outcomes

The realization of these goals will:

• Radically advance mechanical quantum sensing.
• Create coherent interfaces for quantum communication.
• Establish novel ways to control light and motion at the quantum level.

Moreover, we will gain a new fundamental understanding of metrology and sensing performance in basic systems that transcend the mechanical domain.

Conclusion

Finally, these foundational experiments will bring intriguing quantum effects into full view in ‘tangible’ objects and test whether they can in fact exist at such macroscopic scales.