Trio received the Nobel Prize in Physics

0
90

Published 4 October 2022 at 15.07

Domestic. The 2022 Nobel Prize in Physics goes to the three scientists Alain Aspect, John F. Clauser and Anton Zeilinger “for experiments with entangled photons that demonstrated violations of Bell inequalities and paved the way for quantum information science”.

Like the article onå Facebook

“Alain Aspect, John Clauser and Anton Zeilinger have each made groundbreaking experiments with entangled quantum states, where two particles belong together as a unit even when they are separated. With their results, they have paved the way for new technologies built on quantum information,” writes Royal Vetenskapsakademien.

The elusive effects of quantum mechanics are beginning to find applications. Today there is a large field of research that deals with, among other things, quantum computers, quantum networks and interception-proof quantum encrypted communication.

One of the keys to this development is that quantum mechanics allows two or more particles to be in something called an entangled state. What happens to one of the particles in an entangled particle pair determines the fate of the other particle, even if it is at a great distance.

The question has long been whether the connection could be due to the fact that the particles in an entangled pair contain hidden variables, instructions that tell them what outcome to produce in an experiment. In the 1960s, John Stewart Bell developed the disparity that bears his name. It states that if there are hidden variables, the correlation between the outcomes of a large number of measurements can never exceed a certain value. Quantum mechanics, on the other hand, predicts that a certain type of experiment will violate Bell's inequality and thus give a stronger connection than is otherwise possible.

John Clauser further developed John Bell's ideas into a practically feasible experiment. When he made his measurements, the result supported quantum mechanics, by clearly violating a Bell similarity. This means that quantum mechanics cannot be replaced by a theory with hidden variables.

Some loopholes still remained after John Clauser's experiments. Alain Aspect developed the experiment and used it to close an important loophole. He was able to switch the settings of the measurement after an entangled pair had left its source, so that the arrangement prevailing when they were sent out could not affect the outcome.

With refined tools, Anton Zeilinger was able to begin using entangled quantum states in a long series of different experiments. For example, his research group demonstrated a phenomenon called quantum teleportation, which makes it possible to move a quantum state from one particle to another that is far away.

– In recent years, it has become increasingly clear that a new type of quantum technology is emerging. We now see that the laureates' work with entangled states is important even beyond the fundamental questions of how quantum mechanics should be interpreted, says Anders Irbäck, chairman of the Nobel Committee for Physics, in a statement.