两量子比特非线性相互作用模型中的量子关联？
Quantum correlations of a two-qubit system using nonlinear interaction models

运用量子态变换的方法论证了两个qubit纯态中量子关联与纠缠的等价性。并利用三种带有横场的非线性相互作用模型研究了两个qubit体系中的量子关联。发现合适的横场对于最大量子关联态的获得、平均量子关联的提高都有着积极的作用。两个qubit体系获得最大量子关联时，不同模型，不同的横场，对应的量子态却各不相同。
We demonstrate an equivalent relation among the quantum discord, geometric quantum discord and concurrence for pure states of a two-qubit system with local unitary transformations. For illustrations, the equivalent relation is examined by three nonlinear interaction models with external transverse fields. It is found that, with an appropriate transverse field, states with maximal quantum correlations can be obtained and average quantum correlation is enhanced. However, the maximal quantum correlation states of the two-qubit are different in the three models with different external transverse fields.