Electrical Readout of Levitated Superconducting Particles

Magnetic levitation of microscopic, superconducting particles in persistent-current traps is projected to be the most powerful method to study the quantum mechanics of massive systems. Its advantages arise from the noise-free trap formed by persistent supercurrents, and the ultrahigh levels of vacuum that can be reached at milli-Kelvin temperatures. We have embarked on a quest to reach ground-state cooling in such a system. The crucial next step in this journey is the direct readout of the particle motion using a superconducting quantum interference device (SQUID). ELISA will provide the essential ingredient by enabling readout at the level of a single quantum of motion.