The interaction of the qubit with its environment induces the qubit dissipation or dephasing, which causes the qubit collapse from a coherent superposition state to a mixed or pure state. This process is known as quantum decoherence. The radiation and absorption of the three-level atom is studied. Basis on theories of quantum mechanics and Kraus operator and utilizing the reducible density rectangular method the transformation of density matrix of the three-level atom which simultaneously in the case of the radiation and absorption is investigated. The coherence properties of quantum states ar...
