Single and double changes of entanglement

Abstract

Entanglement behavior for different classes of two qubit systems passing through a generalized amplitude damping channel is discussed. The phenomena of sudden single, double changes and the sudden death of entanglement are reported for correlated and non- correlated noise. It is shown that, for less entangled states, these phenomena appear for small values of channel strength. The effect of the channel can be frozen for these classes as one increases the channel strength. Maximum entangled states are more fragile than partial entangled states, where the entanglement decays very fast. However, one can not freeze the effect of the noise channel for systems initially prepared in maximum entangled states. The decay rate of entanglement for systems affected by non-correlated noise is much larger than that affected by correlated noise.