Quantum nondemolition measurement of mechanical motion quanta

• Published in: Nature communications 2018-09, Vol.9 (1), p.3621-8, Article 3621
• Main Authors: Dellantonio, Luca, Kyriienko, Oleksandr, Marquardt, Florian, Sørensen, Anders S.
• Format: Article
• Language: English
• Subjects: 639/766/1130/2800; 639/766/483/1139; 639/766/483/3925; Couplings; Electromechanics; Energy; Energy levels; Humanities and Social Sciences; Mechanical oscillators; Mechanical systems; multidisciplinary; Opto-mechanics; Physics; Quantum nondemolition; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-06070-y

The fields of optomechanics 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 make the detection of the mechanical mode occupation difficult, typically requiring the single-photon strong-coupling regime. Here, we propose and analyse an electromechanical setup, which allows us to overcome this limitation and resolve the energy levels of a mechanical oscillator. We found 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. Although electro-and optomechanics has recently moved towards the quantum regime, the quantized energy spectrum of a mechanical oscillator has not been directly observed. Here Dellantonio et al. propose an electromechanical setup with a membrane resonator that could enable phonon number measurements.