Nonextensive approach to decoherence in quantum mechanics

We propose a nonextensive generalization (q-parametrized) of the von Neuman n equation for the density operator. Our model naturally leads to the pheno menon of decoherence, and unitary evolution is recovered in the: limit of q --> 1. The resulting evolution yields a nonexponential decay for quantum c oherences, fact that might be attributed to nonextensivity. We discuss, as an example, the loss of coherence observed in trapped ions. (C) 2001 Elsevi er Science B.V. All rights reserved.