Frustration, interaction strength, and ground-state entanglement in complex quantum systems

The phenomenon of ground-state entanglement was related to frustration in spin systems. The frustrated spin system consisted of a triangular arrangement of three spin-1/2 particles, each pair being coupled by a classical antiferromagnetic coupling. It was proved that the amount of ground-state entanglement is bounded above by a measure of the extent to which interactions frustrate the local terms in the Hamiltonian. The results show that the amount of ground-state entanglement is bounded above by a ratio between parameters characterizing the strength of interactions in the system and the local energy scale