"The control of microscopic physical systems has been demonstrated successfully in numerous experiments, in particular in the field of quantum optics. A current endeavor is to achieve this level of quantum-mechanical control also in the macroscopic domain. Promising systems for this purpose are mechanical oscillators. Quantum-controlled mechanical oscillators would enable fascinating tasks: to study fundamental physics in a completely new parameter regime, to perform quantum information processing on a macroscopic scale and to design ultra-sensitive, quantum-limited measurement devices. The goal of this research proposal is to demonstrate quantum-control of a micrometer-sized mechanical oscillator and to utilize it for a crucial quantum information application: teleportation. Optomechanical oscillators are used for this purpose, which constitute mechanical oscillators coupled to light. These devices exploit the precise control one has achieved over the quantum states of light in order to perform the required control of the mechanical oscillator. The first objective of this research project aims at preparing low-entropy mechanical states such as the ground state of an optomechanical oscillator. Based on the latter, the next objective is to create and verify entangled optomechanical states. Entangled states only appear in quantum mechanics and are the resource in numerous quantum information applications, which outperform by far some classical tasks. For the final objective, the created optomechanical entanglement is utilized for teleportation. The teleportation protocol will open the door to the preparation of a variety of mechanical quantum states by choosing suitable input light states. These objectives will assign mechanical oscillators to the quantum-controlled physical systems.The Marie Curie IEF will give Dr. Wieczorek the opportunity to undertake this ambitious research project in the renowned research group of Prof. Aspelmeyer in Vienna, Austria."