laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Monday 15th October 2018 – 13H30 – Conf IV – E244

Jérémie Viennot (Institut Néel, Grenoble)
Phonon number sensitive electromechanics

The position of micromechanical oscillators can be controlled and measured with a precision better than their quantum zero-point motion. But because of these quantum fluctuations, the energy of the oscillator cannot be controlled at the quantum scale through coupling to position. We demonstrate a new class of electromechanics experiments in which we use the strong intrinsic non-linearity of a microwave superconducting qubit with a 4 GHz transition frequency to directly detect and control the energy of a micro-mechanical oscillator vibrating at 25 MHz. The qubit behaves as a vibrational energy detector and from its lineshape we extract the phonon number distribution of the oscillator. We manipulate this distribution by driving number state sensitive sideband transitions and creating profoundly non-thermal states. By driving the lower frequency sideband transition, we cool the oscillator and increase its ground state population up to 0.48±0.13, close to a factor of 8 above its value at thermal equilibrium. Finally, preliminary results show our ability to prepare and detect non-classical states of motion.