Causality and decoherence in the asymmetric states

Formal quantum causal analysis is applied to the three-qubit states. 'Quantum causality' means asymmetry in the transfer of information. It leads to different entanglement decay of the system at decoherence of different subsystems. The relationship between decoherence (by dissipation, depolarization and dephasing) and causal connections for the different model states has been studied. Generally, this relationship turns out to be rather sophisticated, although some simple relations have been established. So, the dissipated one-particle party tends to be the effect with respect to the rest of the system, while the depolarized one tends to be the cause. In the asymmetric states, the dissipation and depolarization acting along original causality destroy entanglement to a lesser degree than against it. The decohered internal (inside a subsystem) effect destroys entanglement to a lesser degree than the decohered internal cause.