Volume 99, Number 4, August 2012
|Number of page(s)||5|
|Published online||21 August 2012|
Time-optimal processes for interacting spin systems
1 Institute of Physics, Chemnitz University of Technology - D-09107 Chemnitz, Germany
2 Department of Mathematical Science, San Diego State University - San Diego, CA, 92182, USA
3 Fritz Haber Research Center for Molecular Dynamics, Hebrew University of Jerusalem - Jerusalem, 91904, Israel
Received: 23 May 2012
Accepted: 17 July 2012
Reversible adiabatic processes connecting thermal equilibrium states are usually considered to be infinitely slow. Recently, fast reversible adiabatic processes for quantum systems have been discussed. Here we present time-optimal processes for a paradigmatic ensemble of two interacting spin- systems in an external magnetic field, which previously had been employed as working fluid in a quantum refrigerator. These processes are realized by appropriate bang-bang or quasi–bang-bang controls of the external magnetic field. Explicit control protocols including the necessary times for a transition connecting thermal equilibrium states depending on the limiting conditions on the magnetic field strength are presented.
PACS: 05.10.-a – Computational methods in statistical physics and nonlinear dynamics / 02.30.Yy – Control theory / 37.10.Jk – Atoms in optical lattices
© EPLA, 2012
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