The Nobel Prize in Physics 2022

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Nobel Prize in Physics: About the research:

Scientists Alain Aspect (France), John Clauser (the US), and Anton Zeilinger (Austria) conducted study on the phenomenon of quantum entanglement have won the Nobel Prize in Physics 2022.
Their experiments proved that the ‘entanglement’ phenomenon observed in quantum particles was real, and not a result of any ‘hidden’ or unknown forces.
Their study could be utilized to make transformative technological advances in computing, hack-free communications, and concepts like ‘teleportation’.

By start of 20th century, scientists observed that tiny sub-atomic particles like protons or electrons were not consistent with the classical Newtonion laws of physics.
Further studies in this regard gave rise to Quantum Theory, which described the bizarre behaviour of sub-atomic particles with remarkable accuracy.
Properties:
- Superimposition: A property known as superimposition allowed particle to exist simultaneously at multiple locations. The chance of finding the particle at any given place was based on probabilistic calculations, and once it was found at one location, it ceased to exist at all other places.
- Entanglement: If two particles had ‘interacted’ with each other at some stage, they were found to have got ‘entangled’ in a way that the behaviour of one produced an instantaneous reaction in the other. This was possible even if they were no longer connected in any way and were separated by very large distances.
Problems with quantum theory: The prediction made by Quantum Theory was obeyed by the sub-atomic particles. The only issue was that an experiment to test a phenomenon like entanglement did not appear feasible.

The test for quantum entanglement was the Bell’s inequality test. If inequality was maintained in the results of the experiment, it would mean that Einstein was right in saying Quantum Theory was not yet complete.
- If violated, it would prove the predictions of Quantum Theory.
Clauser’s experiments: Clauser was the first to set up an experiment to test entanglement. His experiments produced results that violated Bell’s inequality.
- However, critics pointed to certain parts of the experiment which could have influenced a favourable result.
Aspect’s contributions: Aspect improved the set-up of Clauser and removed all the loopholes critics had found.
- The experiments by Aspect also produced results that violated Bell’s inequality.
Zeilinger’s contributions: Zeilinger demonstrated that it was possible to ‘teleport’ the quantum states of a particle to another location without the particle moving anywhere and without a medium
- As per Zeilinger, while physical teleportation was still in the realm of science fiction, quantum teleportation could ferry all the information of a mass, any mass, of entangled particles to another mass of entangled particles in the future.
- Once the information was transferred, new mass would have the same characteristics as the original mass.

In the 1960s, John Stewart Bell developed the mathematical inequality that is named after him.
This Inequality stated that if a large number of measurements of the hidden variables were conducted, the correlation between the results could not exceed a certain value.
This in turn meant that no local hidden variable theory could reproduce all the results of quantum mechanics.
But quantum mechanics predicts that a certain kind of experiment can violate Bell’s inequality. This results in a stronger correlation than would otherwise be possible.

The entanglement property has been utilized to build the next generation of computers, called quantum computers.
These experiments have paved the way for quantum information science and quantum cryptography. Quantum Cryptography will help in creating secure communication algorithms that would be immune to hacking.