On capabilities of quantum-mechanical computer models

The work includes the analyses of theoretical capabilities quantum-mechanical versus classical computer models in terms their universality, application domain, efficacy solving problems and technological feasibility. concepts deterministic Turing machine, probabilistic machine are exposed. concept basic information unit modelqubit is introduced qubit represented through use Bloch sphere. Dirac's bra-ket notation description state explained, used to form equation a quantummechanical cell. Especially, consequences quantum parallelism, interference wave function collapse studied respect models. interrelationship between classes that can be efficiently solved by mechanical and/or displayed.