Quantum nondemolition measurement of mechanical motion quanta

TL;DR

This paper proposes an electromechanical system capable of resolving the quantum energy levels of a mechanical oscillator, overcoming environmental limitations faced by optomechanical systems, and enabling phonon number measurement.

Contribution

It introduces a novel electromechanical setup that suppresses heating and allows quantum nondemolition measurement of mechanical motion quanta, advancing quantum state detection.

Findings

Suppression of membrane heating in electromechanical systems.

Feasibility of phonon number measurement with current technology.

Overcoming environmental coupling limitations in quantum measurements.

Abstract

The fields of opto- and electromechanics have facilitated numerous advances in the areas of precision measurement and sensing, ultimately driving the studies of mechanical systems into the quantum regime. To date, however, the quantization of the mechanical motion and the associated quantum jumps between phonon states remains elusive. For optomechanical systems, the coupling to the environment was shown to preclude the detection of the mechanical mode occupation, unless strong single photon optomechanical coupling is achieved. Here, we propose and analyse an electromechanical setup, which allows to overcome this limitation and resolve the energy levels of a mechanical oscillator. We find that the heating of the membrane, caused by the interaction with the environment and unwanted couplings, can be suppressed for carefully designed electromechanical systems. The results suggest that phonon number measurement is within reach for modern electromechanical setups.