The 2022 Nobel Prize in Physics has been awarded to physicists John Clauser, Alain Aspect, and Anton Zeilinger for their independent research on entangled quantum states. Quantum mechanics has its roots in Heisenberg’s Uncertainty Principle, which essentially states that one cannot fully know the position and momentum of a particle with complete accuracy. Einstein, however, questioned the validity of quantum theory. He asserted that according to quantum rules, two particles still affect each other regardless of the distance between them. Einstein was describing quantum entanglement, a state in which two particles are connected so that any action done to one particle impacts the other. At the time, many believed that two particles in an entangled state contained hidden variables, which would explain the results of any one experiment. Using this concept, John Stewart Bell developed Bell’s inequality, which states that there is a limit to the correlation between the outcomes of various measurements. On the other hand, quantum mechanics asserts that there must be an experiment that will allow for the value of the correlation to exceed the value given by Bell’s inequality.
In 1972, Clauser and Stuart Freedman set out to perform this experiment. The two shot thousands of photons in numerous directions, using two detectors to measure polarization. When the results from the two detectors were compared, Clauser and Freedman noticed that they correlated for an unknown reason. Many were concerned that this correlation resulted from the two detectors leaking information to each other, known as the locality loophole. 10 years after Clauser’s original experiment, Aspect and his team attempted to eliminate this loophole by switching the direction of the photons every 10 nanoseconds. This experiment, however, provided similar results and established quantum entanglement as a real possibility. Finally, in 1998, Zeilinger used random number generators to switch the direction of the photons, effectively discrediting the locality loophole as an explanation.
Many scientists have continued verifying quantum entanglement, and it is now a primary feature of quantum mechanics. This finding also has numerous applications, namely in the technological world. It specifically has had a large effect on cryptology, the study of codes. Entanglement can be used to ensure the safe transfer of information across large distances, as any data leaks destroy the entanglement and prevent any information from being leaked. Despite the progress made in quantum mechanics over the years, there are still many unknowns about the field.
“Nobel Prize in Physics Is Awarded to 3 Scientists for Work Exploring Quantum Weirdness” – New York Times:
https://www.nytimes.com/2022/10/04/science/nobel-prize-physics-winner.htmln “Press Release: The Nobel Prize in Physics 2022” – Nobel Prize:
https://www.nobelprize.org/prizes/physics/2022/press-release/ “Nobel Prize for Quantum Physicists Who Explained Particles ‘Spooky Behvior’” – CNN: https://www.cnn.com/2022/10/04/europe/nobel-prize-physics-winner-2022-intl-scn
By: Elizabeth Ogden’24, SNHS Member