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TT: Tiefe Temperaturen

TT 29: Quantenkoh
ärenz und Quanteninformationssysteme II

TT 29.12: Vortrag

Donnerstag, 11. März 2004, 17:30–17:45, H19

Quantum Control: Mechanical Versus Thermodynamical Aspects — •Harry Schmidt und Günter Mahler — Universität Stuttgart, Institut für Theoretische Physik 1, Pfaffenwaldring 57, D-70550 Stuttgart

External quantum control is usually taken to mean that certain classical parameters entering the Hamiltonian of the controlled quantum system can be changed from the outside. To exert such a control one may be tempted to use another (mesoscopic) quantum system.

We investigate the conditions under which such a mesoscopic system may, indeed, act like a classical (mechanical) control on the one hand or as a bath on the other hand with respect to the state evolution of the controlled microscopic system. Both control features can be used as working parts of quantum thermodynamical machines. The actual control mode depends on the state of the system as a whole, the state of the mesoscopic object, in particular, and parameters of the interaction that are easily accessible and adjustable in an experimental setup. These parameters thus provide an external control of the behavior of the mesoscopic system.