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Recent work has relatively comprehensively studied the quantum discord, which is supposed to account for all the nonclassical correlations present in a bipartite state (including entanglement), and provide computational speedup and quantum enhancement even in separable states. Firstly, we introduce several different indicators of nonclassical correlations, including their definitions and interpretations, mathematical properties, and the relationship between them. Secondly, we review two major topics of quantum discord. One is the remarkable behavior at quantum phase transitions. The pairwise quantum discord for nearest neighbors as well as distant spin pairs can perfectly signal the critical behavior of many physical models, even at finite temperatures. The other is quantum discord dynamics in open systems, especially for "system-spin environment" models. Quantum discord is more robust than entanglement against external perturbations. It can be created, greatly amplified or protected under certain conditions, and presents promising applications in quantum technologies such as quantum computers. [ABSTRACT FROM AUTHOR]

Abstract: Taking the intrinsic decoherence effect into account, the tripartite nonlocality is measured by the extent of violation of multipartite Bell inequality in a three-qubit Heisenberg XY chain in the presence of an external magnetic field. It is shown that multipartite Bell-inequality violations can be destroyed in finite time in the system and the influence of the intrinsic decoherence on the tripartite states Bell-nonlocality sudden death is demonstrated. [Copyright &y& Elsevier]