Quantum computation (QC) is expected to improve the efficiency of certain computational tasks. QC schemes are formulated in terms of operations on quantum bits (qubits), whose values are superpositions of two quantum states. A natural candidate for the physical implementation of a qubit is the spin of an electron. In fact, breakthrough experiments recently demonstrated the ability to initialize, manipulate, couple and read out spin-based qubits using electrons confined in a solid state environment. New perspectives have been opened in solid-state QC by recent proposals exploiting the peculiar characteristics of carbon nanotubes (CNTs): utilizing electronic states circulating around the CNT circumference in qubit implementation is promising for various reasons. To evaluate the potential in these novel qubit realizations, we plan to develop a profound theoretical understanding of the physical mechanisms allowing initialization and readout of the qubit, causing two-qubit interactions, as well as those leading to the loss of information encoded in the qubit. We expect that our results will enable the design of carbon nanostructures optimized for QC, provide understanding of related recent and future experiments, and highlight fundamental new quantum-physical phenomena on the nanoscale.The completion of the project requires tools of condensed matter theory (tight-binding and envelope-function models, theories of hyperfine, spin-orbit, exchange and electron-phonon interactions), and the theory of non-equilibrium quantum systems (quantum master equation).The EU contribution would enable the applicant to establish himself in Hungary after his mobility period, contribute significantly to the scientific success of his research career, improve considerably the prospects of his permanent integration, allow the transfer of knowledge he has acquired abroad, and enable him to maintain co-operation with the scientific and industrial environment of the countries he visited.