Scaling, Entanglement and Quantum Phase Transitions

In this Letter we discuss the entanglement near a quantum phase transition by analyzing the properties of the concurrence for a class of exactly solvable models in one dimension. Entanglement can be classified in the framework of the scaling theory of phase transition. There is a profound difference between the classical correlations, whose correlation lenght diverges at the phase transition, and non-local quantum correlations that remain, in general, short ranged.