The paper by Vidal, Latorre, Rico, and Kitaev explores the entanglement properties in quantum critical phenomena, focusing on 1D spin chain models. They compute the scaling properties of ground-state entanglement near and at quantum critical points, quantifying it through the entropy of the ground state when traced down to \( L \) spins. The entropy is found to scale logarithmically with \( L \), with a coefficient corresponding to the central charge of the conformal theory describing the universal properties of the quantum phase transition. This reveals that entanglement follows universal scaling laws dictated by the conformal group and its classification motivated by string theory. The authors also identify a majorization rule possibly associated with conformal invariance and apply these results to interpret the breakdown of density matrix renormalization group techniques near critical points. The study highlights the connection between quantum information science and conformal field theory, providing insights into the nature of quantum correlations and the behavior of critical systems.The paper by Vidal, Latorre, Rico, and Kitaev explores the entanglement properties in quantum critical phenomena, focusing on 1D spin chain models. They compute the scaling properties of ground-state entanglement near and at quantum critical points, quantifying it through the entropy of the ground state when traced down to \( L \) spins. The entropy is found to scale logarithmically with \( L \), with a coefficient corresponding to the central charge of the conformal theory describing the universal properties of the quantum phase transition. This reveals that entanglement follows universal scaling laws dictated by the conformal group and its classification motivated by string theory. The authors also identify a majorization rule possibly associated with conformal invariance and apply these results to interpret the breakdown of density matrix renormalization group techniques near critical points. The study highlights the connection between quantum information science and conformal field theory, providing insights into the nature of quantum correlations and the behavior of critical systems.