Nobel Prize in physics 2022

 

The unspeakable effects of quantum mechanics are beginning to find application. There is now a large field of research that includes quantum computers, quantum networks, and secure quantum encrypted communication.

One of the key factors in this development is how quantum mechanics allows two or more particles to exist in a so-called entangled state. What happens to one of the particles in an entangled pair determines what happens to the other particle, even if they are far apart.

The question has long been whether the correlation is due to the fact that the particles in the entangled pair contain hidden variables, instructions that tell them what result they should give in an experiment. In the 1960s, John Stewart Bell developed the mathematical inequality that is named after him. This says that if there are hidden variables, the correlation between the results of a large number of measurements will never exceed a certain value. However, quantum mechanics predicts that a certain type of experiment will violate Bell's inequality, leading to a stronger correlation than would otherwise be possible.

The 2022 Nobel Prize in Physics was awarded jointly to Alain Aspect, John F. Clauser, and Anton Zeilinger "for experiments with entangled photons that demonstrated violations of Bell's inequalities and for pioneering quantum information science"

Each performed groundbreaking experiments using entangled quantum states, where two particles behave as a single unit even when separated. Their results paved the way for a new technology based on quantum information.

John F. Clauser developed John Bell's ideas, leading to a practical experiment. When he made measurements, they supported quantum mechanics with a clear violation of Bell's inequality. This means that quantum mechanics cannot be replaced by a theory that uses hidden variables.

Some gaps remained after John Clauser's experiment. Alain Aspect developed the setting and used it in a way that closed a significant gap. He was able to change the measurement settings after the tangled pair left their source so that the settings that existed when they were broadcast could not affect the result.

Using sophisticated tools and a long series of experiments, Anton Zeilinger began using entangled quantum states. Among other things, his research group has demonstrated a phenomenon called quantum teleportation, which makes it possible to move a quantum state from one particle to another at a distance.