Contextuality of quantum states: Theoretical Analysis and Experimental Investigations

Abstract

It is a common notion in classical mechanics that the result of a measurement depends on the observable measured and the system in consideration. From the measurement outcomes, it is possible to assign the pre-measurement state of the system. But the same may not hold in quantum mechanics. Quantum mechanics is known to be a contextual theory. We cannot assign the premeasurement states from the measurement outcomes, and hence quantum states can be contextual. We have done theoretical analysis and experimental demonstration of quantum contextuality. I have studied Bell's inequality and Kochen- Specker theorem. There are many forms of quantum contextuality. We have demonstrated Peres contextuality experimentally. We have taken a two spin half system to do the experiment. We have used a newly discovered technique in NMR called Moussa protocol. The results are in good accordance with the theory. We are also reporting continuously varying contextual operators. Inequality for spin 1 particle is also studied, which is called the pentagram inequality. Fully contextual quantum correlations were also studied.