Active noise control for a quantum drum

Researchers at the Schliesser Lab at the Niels Bohr Institute, University of Copenhagen, have demonstrated a new way to address a central problem in quantum physics: at the quantum scale, any measurement disturbs the measured object. This disturbance limits, for example, the precision with which the motion of an object can be tracked. But in a millimeter-sized membrane that vibrates like a drumhead, the researchers have managed to precisely monitor the motion with a laser—and to undo the quantum disturbance by the measurement. This allows them to control the membrane's motion at the quantum level. The result has potential applications in ultraprecise sensors of position, velocity and force, and the architecture of a future quantum computer. It is now published in the prestigious scientific magazine, Nature.