https://doi.org/10.1140/epjb/e2008-00270-2
Quantum thermodynamic processes: a control theory for machine cycles
1
Chair for Theoretical Physics and Applied Mathematics, Urals State Technical University, Mira 19, 620002 Jekaterinburg, Russia
2
Institut für Theoretische Physik 1, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
Corresponding author: a jan.birjukow@daad-alumni.de
Received:
8
November
2007
Revised:
20
May
2008
Published online:
9
July
2008
The minimal set of thermodynamic control parameters consists of a statistical (thermal) and a mechanical one. These suffice to introduce all the pertinent thermodynamic variables; thermodynamic processes can then be defined as paths on this 2-dimensional control plane. Putting aside coherence we show that for a large class of quantum objects with discrete spectra and for the cycles considered the Carnot efficiency applies as a universal upper bound. In the dynamic (finite time) regime renormalized thermodynamic variables allow to include non-equilibrium phenomena in a systematic way. The machine function ceases to exist in the large speed limit; the way, in which this limit is reached, depends on the type of cycle considered.
PACS: 05.30.-d – Quantum statistical mechanics / 05.70.Ln – Nonequilibrium and irreversible thermodynamics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008