Nanoscopic quantum networks: collective versus selective control

Present-day information processing is based on the rules of classical physi cs. If the ubiquitous superposition principle of quantum mechanics could be harnessed, quite different and surprising rules would be at our disposal. They would give rise to the celebrated quantum parallelism allowing, e.g. f or an increased efficiency of quantum over classical computing. To achieve this goal there are at least two different paradigms which could be exploit ed: 'selective control' and 'collective control'. The latter should be an i nteresting alternative for nanoscopic quantum networks. Copyright (C) 2001 John Wiley & Sons, Ltd.