A quantum connection between light and motion

Researchers have demonstrated a microscopic system in which light can be converted into a mechanical oscillation and back. This interaction is so strong that it becomes possible to control the motion of the oscillator at the level where quantum mechanics governs its behaviour. Since the early 20th century, it is known that the movement of objects is ultimately governed by the laws of quantum mechanics, which predict some intriguing phenomena: An object could simultaneously be in two places at the same time, and it should always be moving a little, even at a temperature of absolute zero - the oscillator is then said to be in its quantum ground state. Yet we never experience such behaviour in the things we see around us and interact with in daily life. Quantum strangeness Indeed, quantum effects can only be observed on very well isolated systems, where the coupling to the surrounding environment is extremely weak. For large objects, the unavoidable coupling quickly washes out the quantum properties, in a process known as decoherence. Until recently, scientists were only able to observe quantum mechanical traits in the motion of tiny systems, such as single atoms or molecules. Now, a team of physicists at EPFL has shown that it is possible to control the motion of an object, sufficiently large to be seen with the naked eye, at the level where quantum mechanics dominates. A ring of light