The coupling of three components an optomechanical system operating close to its quantum ground state is shown in Nature Communications this week. The findings are an important demonstration of control for potential quantum technology.

Understanding the quantum behaviour of macroscopic objects is crucial to explaining the transition between classical and quantum phenomena on small length scales. It is also key to developing quantum technologies. Mika Sillanpaa and colleagues investigate the response of a system comprising two micromechanical beams and an optical cavity, working in a regime close to the quantum mechanical ground state of the beams. They find a coupling between the structural vibrations of the beams and the light cavity, providing the first evidence of tripartite mixing in such a system. This implies that the fundamental behaviour arises from combinations of mechanical vibrations and light oscillations, with no component being independent from the others. Exploiting the radiation pressure from the cavity, the whole system is cooled to operate in a nearly pure quantum state.

These observations demonstrate a possible chip-scale platform for studying non-classical states, which may form a basis for quantum technology including data storage.