Theoretical study of the resonant excitations in coupled Josephson-junction qubits

The superconducting qubits are nowadays considered as good candidates both for building a quantum computer and for the study of the quantum erects in macroscopic systems. The system of two coupled qubits can be described by the Liouville equation. We convert the Liouville equation in the system of real equations by making use of the convenient parametrization of the reduced density matrix. Phenomenological inclusion of the relaxation is presented. The time evolution of the levels population in coupled flux qubits is calculated by solving the Bloch-Redfield equations.