Modelling of Quantum Qubit Behaviour for Future Quantum Computers

This work deals with quantum qubit modelling based on a silicon material with embedded phosphorus atoms because a future quantum computer can be built on the basis of this qubit. The building of atomic models of bulk crystalline silicon and silicene, as well as calculation of their total energies, were performed using the Quantum ESPRESSO software package, using highperformance computing (HPC). For silicon and phosphorus atoms the generalized gradient approximation (GGA) was used in terms of the spin-orbit non-collinear interaction by means of the Quantum ESPRESSO package. The equilibrium orientations of the phosphorus qubit spins and localization of the wave functions in the 2D and bulk crystalline silicon phases were theoretically investigated by means of quantum-mechanical calculations. The existence of an exchange interaction between qubits has been confirmed, which leads to a change in the wave function’s localization and spin orientation, and in the case of silicene, this interaction was stronger.