Quantum systems versus classical networks

Quantum cellular neural networks are cellular neural networks whose cells are reduced to nano size. Such cells work according to quantum dynamics but interact among themselves in a classical way; moreover they interact with inputs and outputs that can be described in classical circuit terms. Hence follows the necessity of establishing a bridge between concepts of quantum mechanics and of network theory. In this paper we present, as an example, the extension to simple quantum systems of the network concepts of passivity and losslessness.