Experimental non-classicality of an indivisible quantum system

Understand

Quantum theory demands that, in contrast to classical physics, not all properties can be simultaneously well defined.

• The Heisenberg Uncertainty Principle is a manifestation of this fact.
• Another important corollary arises that there can be no joint probability distribution describing the outcomes of all possible measurements, allowing a quantum system to be classically understood.
• We provide the first experimental evidence that even for a single three-state system, a qutrit, no such classical model can exist that correctly describes the results of a simple set of pairwise compatible measurements.