Time seems to move only from the past to the future. This one-way flow, known as the arrow of time, explains why broken objects do not reassemble and why people grow older rather than younger. While this behaviour defines everyday life, the laws of quantum mechanics allow scientists to explore situations that have no equivalent in the world we experience.
Researchers led by the University of Surrey, working with scientists from the University of Oxford, the University of Bayreuth and the University of Bordeaux, have demonstrated a way to control the arrow of time in a quantum system. Using carefully designed quantum measurements and feedback, they created conditions in which the system evolved as though its direction of time had been reversed.
The experiment did not reverse time itself or make time travel possible. Instead, it manipulated the mathematical evolution of a quantum system under highly controlled laboratory conditions. The study offers new insights into one of physics’ most fundamental questions: why time appears to move only forward. It could also improve quantum technologies, including quantum computers, secure communication systems and ultra-sensitive sensors, all of which depend on precise control of fragile quantum states.
Author
