Invariance of quantum correlations under local channel for a bipartite   quantum state
  We show that the quantum discord and the measurement induced non-locality (MiN) in a bipartite quantum state is invariant under the action of a local quantum channel if and only if the channel is invertible. In particular, these quantities are invariant under a local unitary channel. 
Ali Saif M. Hassan and Pramod S. Joag
quant-ph