The Photonics and Semiconductor Nanophysics group at the Eindhoven University of Technology (The Netherlands, http://www.tue.nl/psn) has an open PhD student position in the field of quantum acoustics. Atoms and photons have long been used to investigate quantum physics and its application to quantum information processing. A new quantum bit is now appearing on the horizon of science and technology: The phonon. High-frequency phonons in solids have long coherence times, can be controlled with nanopatterned structures, and interact with many other quantum systems. For this reason they represent ideal candidates for quantum interfaces, among others. The first experiments and protocols involving single phonons are being deployed [1,2], opening the way to the new scientific field of "quantum acoustics". However, similarly to photons, the equispaced energy level structure makes nonlinear interactions and the controlled creation of quantum states difficult. This can be circumvented by using intrinsically nonlinear two-level systems in order to mediate nonlinear interactions between phonons. Our group has proposed a scheme to realize a controllable interaction between phonons and solid-state two-level systems [3]. In the framework of a newly funded national program on Quantum Acoustics, we intend to experimentally investigate this and other approaches to the quantum control of phonons in the solid-state. This would have large impact on the development of the field and of its application within quantum information processing. The selected candidate will perform fundamental research at the interface between nanophotonics, quantum optics and optomechanics. He/she will conceive semiconductor nano-optomechanical structures based on photonic crystals with embedded quantum dots and will use them to experimentally investigate the radiative emission of excitons in the quantum dots within a nanomechanical cavity. Together with collaborators in AMOLF and Delft University, we specifically aim at demonstrating controlled exciton-phonon interaction and the emission of single phonons from quantum dots. The project will be co-supervised by Prof. A. Fiore (TU/e) and Prof. Ewold Verhagen (AMOLF).