Quantum correlations dynamics and decoherence of a three-qubit system subject to classical environmental noise

Abstract

We address the dynamics of decoherence and quantum correlations (entanglement and discord) in a model of three non-interacting qubits, initially prepared in a maximally entangled pure Greenberger-Horne-Zeilinger (GHZ) state and then subjected to classical environmental noise in common, different and mixed environments. The noise is modeled by randomizing the single-qubit transition amplitudes. We address both static and colored environmental noise. We find that the dynamics of quantum correlations are strongly affected by the type of system-environment interaction and the kind of the noise considered. On the one hand, our results clearly show that unlike what was found in the case of the two-qubit model analogous to the one here investigated, quantum correlations are not totally destroyed when the qubits are coupled to the noise in a common environment. On the other hand, the presence or absence of peculiar phenomena, such as entanglement, revivals and sudden death are observed. Furthermore, we show that the partial preservation of entanglement can be successfully detected by means of the suitable entanglement witness. Finally, in the case of static noise we find that the decoherence becomes stronger as the disorder of the environment increases whereas, for colored noise, it becomes stronger as the number of fluctuators increases.