Researchers at MPQ, ICFO, University of Innsbruck and the Center for Theoretical Physics of the Polish Academy of Sciences have developed a new method to show that the low energy states of some physical spin Hamiltonians can exhibit these nonlocal correlations.
Classical correlations are part of our everyday experience. For instance, if one always puts on a pair of socks of the same colour and shape, looking at the colour or shape of one sock determines the colour or shape of the other one. Moreover, one can observe the colour and shape of one sock simultaneously, and these will tell us the colour and shape of the other one. Entangled states, the paradigmatic form of quantum correlations, defy this basic principle: if the socks were entangled, observing the colour of one sock would allow us to predict the colour of the other, but if, at the same time, we would observe the shape, this would "disturb" the colour, which would become completely unpredictable. This weird "coordination" between particles is known as quantum entanglement and is one of the intrinsic features of the quantum world.
To read more, click here.