Effects of environmental parameters to total, quantum and classical   correlations
  We quantify the total, quantum, and classical correlations with entropic measures, and quantitatively compare these correlations in a quantum system, as exemplified by a Heisenberg dimer which is subjected to the change of environmental parameters: temperature and nonuniform external field. Our results show that the quantum correlation may exceed the classical correlation at some nonzero temperatures, though the former is rather fragile than the later under thermal fluctuation. The effect of the external field to the classical correlation is quite different from the quantum correlation. 
Wen-Ling Chan, Jun-Peng Cao, Dong Yang, and Shi-Jian Gu