A realistic approach to the problem of using the laws of quantum mechanics for information processing is offered by superconducting devices such as charge qubits. These devices satisfy the requirements of integrability, flexibility in design, and long enough coherence time for quantum manipulations and measurement. The general objective of this project is to study the physics of these systems from the point of view of quantum computing and evaluate their possibilities for quantum state engineering. More precisely, we plan to fabricate and measure the decoherence time in Nb-based Cooper pair boxes and implement quantum algorithms in the circuits containing these devices. Besides this experimental direction, there will be a thorough theoretical investigation of their noise and decoherence properties. This will lead to a better understanding of the measurement-induced decoherence for read-out devices such as r.f. SET' s, and to a quantitative theory of quantum leakage errors and background charge noise. Finally, evaluating the potential of solid-state superconducting devices for a variety of macroscopic states based effects similar to the ones in quantum optics is considered as a promising avenue of research. The host institution has extensive expertise in superconducting nanotechnologies; quantum computing with Cooper pair boxes has been a major research direction in the last few years. The institution is at the frontline of research in the field related to the applicant's project, thus it will provide an excellent training environment. For the host, the benefit consists in having in an experimental group a researcher with a theory background in quantum information, decoherence, and macroscopic quantum coherence. For the applicant, working in an experimental group both on experimental and theoretical projects should result in direct contact with important concrete problems to solve. It is usually through this kind of collaboration that excellent physics emerges.