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Physical Society Colloquium
Martin Dubé
Centre for the Physics of Materials Friction, dissipation and decoherence occur in many physical problems and on scales ranging from nanometers to geological distances. These phenomena ultimately arise from the interaction of a given system with its surrounding environment and are important both in the quantum and classical regime, as well as on the semi-classical border. The context of quantum computation and quantum mechanics at the macroscopic scale will first be used to introduce a general type of environment and to descibe the dissipative quantum dynamics of single and coupled 2-level systems. It will also be seen that a generalised quantum Langevin equation can provide a link between the quantum and classical regimes. This can then be used to discuss friction between macroscopic objects, a specific example being the tip of an Atomic Force Microscope dragged along a surface.
>Friday, January 18th 2002, 15:30 |