Europhys. Lett.
Volume 75, Number 2, July 2006
Page(s) 209 - 215
Section General
Published online 23 June 2006
Europhys. Lett., 75 (2), pp. 209-215 (2006)
DOI: 10.1209/epl/i2006-10108-7

Stochastic unraveling of the time-evolution operator of open quantum systems

A. Karpati1, P. Adam1, 2, Z. Kis1 and J. Janszky1, 2

1  H.A.S. Research Institute for Solid State Physics and Optics H-1525 Budapest, P.O. Box 49, Hungary
2  H.A.S. Research Group for Nonlinear and Quantum Optics and Institute of Physics, University of Pécs Ifjúság út 6., H-7624 Pécs, Hungary

received 31 January 2006; accepted in final form 30 May 2006
published online 23 June 2006

The time-evolution operator of open quantum systems is determined generally via a stochastic operator sum representation. Quantum trajectories originating from any quantum trajectory method applicable to the system can be used for the construction. The result does apply to non-Markovian systems as well. The computational time reducement is in the order of the dimension of the Hilbert space compared to conventional quantum trajectory methods combined with algebraic reconstruction of the map. To demonstrate the efficiency of the method, the effects of decoherence are analysed for a C-NOT gate realized by two atoms in a cavity.

03.67.Lx - Quantum computation.
42.50.Lc - Quantum fluctuations, quantum noise, and quantum jumps.
03.65.Yz - Decoherence; open systems; quantum statistical methods.

© EDP Sciences 2006