Non-Markovian dynamics in the extended cluster spin-1/2 XX chain
  We study the dynamics of entanglement in the extended cluster spin-1/2 XX chain, equivalent to a 1D spin-1/2 XX model with three-spin interaction (TSI). Selecting the nearest neighbor pair spins as an open quantum system, the rest of the chain plays the role of environment. The two-spin Heisenberg and the TSI interaction are responsible for coupling between system and environment. We show the existence of a critical value in the TSI, where the dynamics of concurrence changes from Markovian to the non-Markovian. In the region with the non-Markovian dynamics, entanglement sudden death in the system is observed. By focusing on the nearest neighbor pair spins of the environment, we have showed that the dynamics of entanglement in the environment is sensitive to the Markovian and non-Markovian regions. 
M. Mahmoudi, M. R. Soltani, T. Mohammad Ali Zadeh, S. Mahdavifar
quant-ph