Driven spin systems as quantum thermodynamic machines: fundamental limits.
We show that coupled two-level systems like qubits studied in quantum-information processing can be used as a thermodynamic machine. At least three qubits or spins are necessary and they must be arranged in a chain. The system is interfaced between two split baths and the working spin in the middle is externally driven. The machine performs Carnot-type cycles and is able to work as a heat pump or engine depending on the temperature difference of the baths, DeltaT , and the energy difference in the spin system, DeltaE . It can be shown that the efficiency is a function of DeltaT and DeltaE .
Henrich
Markus J
MJ
Institute of Theoretical Physics I, University of Stuttgart, Pfaffenwaldring 57, Stuttgart, Germany. markus.henrich@itp1.uni-stuttgart.de
Mahler
Günter
G
Michel
Mathias
M