Issue
Europhys. Lett.
Volume 76, Number 6, December 2006
Page(s) 1057 - 1063
Section General
DOI http://dx.doi.org/10.1209/epl/i2006-10408-x
Published online 24 November 2006
Europhys. Lett., 76 (6), pp. 1057-1063 (2006)
DOI: 10.1209/epl/i2006-10408-x

Small quantum networks operating as quantum thermodynamic machines

M. J. Henrich, M. Michel and G. Mahler

Institute of Theoretical Physics I, University of Stuttgart Pfaffenwaldring 57, 70550 Stuttgart, Germany

Markus.Henrich@itp1.uni-stuttgart.de

received 24 August 2006; accepted in final form 31 October 2006
published online 24 November 2006

Abstract
We show that a 3-qubit system as studied for quantum information purposes can alternatively be used as a thermodynamic machine when externally driven in finite time and interfaced between two split baths. The spins are arranged in a chain where the working spin in the middle exercises Carnot cycles the area of which defines the exchanged work. The cycle orientation (sign of the exchanged work) flips as the difference of bath temperatures goes through a critical value.

PACS
05.70.Ln - Nonequilibrium and irreversible thermodynamics.
03.65.-w - Quantum mechanics.

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