Levitated superconducting mechanical resonators: a novel platform for quantum experiments and sensing

Research Project, 2020 – 2025

Mechanical resonators are prevalent devices employed for sensing applications. Their relevance ranges from the low-cost mass-market to research at the frontiers of science. Ultimately, their sensitivity is limited by the rules of quantum physics that determine the precision with which a quantity can be measured. Hence, the ultimate levels in sensitivity can only be reached once mechanical motion is controlled in the quantum regime. On the other hand, quantum-controlled mechanical resonators access a novel parameter regime in terms of size and mass for generating quantum states of macroscopic objects. Exploration of such quantum states may pave a way for studying the validity of the quantum superposition principle for macroscopic objects. However, thermal noise poses classical limits to both measurement sensitivity and the life time of quantum states.
This research project will access a novel regime in experimental control over macroscopic quantum systems by employing magnetic levitation of superconducting particles. The levitated particle takes the role of a mechanical resonator that reaches unprecedented levels of isolation from the environment and, concomitantly, a drastic reduction of thermal noise. Coupling to superconducting circuits such as SQUIDs or superconducting qubits allows for precise control over levitated particle motion, in case of sub-micrometer-sized particles down to the quantum regime. These features enable pursuing fascinating opportunities for sensing of weak forces or accelerations, such as exploring potential corrections to Newtonian gravity at short length scales. Furthermore, this platform offers a clear and feasible path to bring massive objects into quantum superposition states. This project lies therefore at the forefront of research in exploring quantum control of levitated mechanical motion as a novel platform for fundamental research and prospective applications.