Optical preparation and readout of mechanical quantum states at room temperature
Prof. Christophe Galland, EPFL
With the advent of quantum technologies, a quest toward the manipulation of mechanical oscillators in the quantum regime has been launched. I will present the experimental research of my group at the boundary between ultrafast spectroscopy, quantum optics and nanoscience, in which we prepare non-classical states of molecular and vibrations.
I will show how we can create a single quantum of vibration involving the collective motion of billions of atoms in a crystal [1,2], and how we can engineer and demonstrate entanglement between light and mechanical motion in this system. Entanglement is strong enough to violate Bell inequalities , showing the strongest form of correlation allowed by quantum mechanics.
I will explain how our technique can be extended to manipulate a broader range of nanoscale oscillators in the quantum regime, enabling new ways to process quantum information at ultrafast timescales, and opening a new window into quantum phenomena occurring in molecular and solid-state systems.
 M. D. Anderson, S. T. Velez, K. Seibold, H. Flayac, V. Savona, N. Sangouard, and C. Galland, “Two-Color Pump-Probe Measurement of Photonic Quantum Correlations Mediated by a Single Phonon,” Phys. Rev. Lett. 120, 233601 (2018).
 S. Tarrago Velez, K. Seibold, N. Kipfer, M. D. Anderson, V. Sudhir, C. Galland. “Preparation and decay of a single quantum of vibration” arXiv preprint arXiv:1811.03038v2 (2018).
 S. Tarrago Velez et al., in preparation (2019).