ИСТИНА

The methods and algorithms of quantum operations modeling for the tasks of making quantum computer integrated circuits are developed. We examine different ways of quantum operation descriptions, including operator sums, unitary representations, Choi-Jamiolkowski state representations and corresponding chi-matrices, as well as quantum system evolution operators. The results of the modeling of practically important quantum gates: SQiSW (square root of i-SWAP gate), controlled-NOT (CNOT), and controlled Z-transform (CZ) subject to different decoherence mechanisms are presented. These mechanisms include the analysis of the depolarizing quantum noise and the processes of the amplitude and phase relaxation. We consider the error correction of the phase flip, and the task of the entanglement onset, maintenance, and destruction during two and many-qubits realization of the quantum operations. In practice, the significance of the realized research is linked to the quality and efficiency of the quantum information technology.