Touching the most foundational problems of quantum theory, Schrödinger’s cat paradox and other contributions still fire heated debates on if and how quantum mechanics can be brought to larger scales. Recent experimental progress with superconducting devices, photons, atomic ensembles and optomechnical systems built up new momentum for these old, but timely questions. Many physicists tried to characterize key aspects of what is sometimes called macroscopic quantum states or, more specifically, Schrödinger-cat states. In this talk, I stress that “macroscopic quantum” is not one dimensional and I try to distill some essence of this debate. Such attempts are important to approach a key question for many recent experiments in the field: How much does the experiment, that is, the idea as well as the measured data, tell us about quantum mechanics at meso- and macroscopic scales?
Group of Applied Physics, University of Geneva