Entanglement and Teleportation: 2nd Quantum Revolution by Prof. P. C. Deshmukh
Channel: Sastri OSKS
Date: 2022-11-01

Quantum Physics was developed in the 1920s by stalwarts like Schrödinger, Heisenberg, Born, Jordan, Dirac, etc. It was soon realized that it superseded classical physics in accounting for the laws of nature. However, it involved a
counterintuitive perception of reality, which triggered a stunning debate among scholars, notably Einstein and Bohr, on whether or not the quantum-mechanical description of physical reality is ‘complete’. The incompleteness suspected by Einstein was on the basis of what seemed to be ‘spooky action at a distance’ that quantum physics entailed; the arguments were raised on principles of locality and counterfactual deﬁniteness. It took more than three decades since this debate (during which quantum devices revolutionized technology) before John Bell set up a mathematical inequality that must be
satisﬁed by all theories that are both local and counterfactual. Quantum correlations observed in the experiments conducted by Alain Aspect, John Clauser, and Anton Zeilinger violate Bell’s inequality leading to the conclusion that quantum theory cannot be both local and counterfactual. The experiments of Aspect, Clauser and Zeilinger demonstrate how the Bohr-Einstein debate is resolved, thereby accounting for quantum entanglement, which enables teleportation of quantum information and creates a platform that revolutionises computing. This pedagogical talk is aimed at
undergraduate students of sciences and engineering to take them on a voyage through the exciting works since the beginnings of quantum physics, the Bohr-Einstein debate, Bell’s inequality, and the experiments of Aspect, Clauser, and Zeilinger. Together, we shall celebrate this year’s Nobel prize, and the second quantum revolution that we ﬁnd ourselves amid.