Quantum Coherence and Degree of Mixedness for a System of Two Superconducting Qubits Under Decohe\rence Conditions

In this work, we study quantum coherence, the degree of mixedness, and total quantum correlation in two interacting superconducting charge qubits (SCQs) in both the absence and presence of intrinsic decoherence. We demonstrate that the quantum phenomena under study can be controlled and preserved during their evolution, depending on the coupling energy between the two SCQs and the Josephson energy of an individual SCQ. These energies can be controlled using the empirical multiplexed capacitance in quantum circuits. We observe an interesting phenomenon, called coherence trapping; it appears along with total correlation trapping in the presence of decoherence after some oscillations. Furthermore, we consider use of linear entropy to explain the dynamic features of quantum coherence. We show that, for the model under study, it is possible to enhance the amount of quantum coherence and maintain this amount in the presence of decoherence by appropriate selection of the system parameters.