Simulation of low-dimensional devices for ultimate nanoelectronics and quantum computation. In particular, studies on the changes of the energy band structure of silicon under strong quantum confinement with applied electric and magnetic fields and with donors by using Constant Interaction models and Density Functional Theory -like programs and k*p methods. Simulations of silicon quantum dot and donor systems to be exploited as qubits and developement of search algorithms to find sequences for logical quantum gates. Studies of noise and non-ideal control effects on quantum gate fidelities. Simulation of quantum error correction codes affected by noise and non-ideal controls in multi-qubit systems for fault tolerant quantum computation.