Dynamics of multi-qubit systems in noisy environment
  Some properties of multi-qubit systems interacting with noisy environment is discussed. The amount of the survival entanglement is quantified for the GHZ and W-states. It is shown that the entanglement decay depends on the noise type ( correlated or non-correlated), number of interacted qubits with the environment and the initial state which passes through this noisy environment. In general, the GHZ is more fragile than the W-state. The phenomena of entanglement sudden death appears only for non-correlated noise. 
N. Metwally and A. Almannaei
quant-ph