%0 Journal Article
%A Luis Aina, Alfredo
%T Zeno and anti-Zeno effects in two-level systems
%D 2003
%@ 1050-2947
%U https://hdl.handle.net/20.500.14352/51521
%X We examine the appearance of Zeno and anti-Zeno effects when the unitary evolution of a two-level system is observed. We demonstrate that, contrary to previous claims, the anti-Zeno effect can occur in two-level systems so that the observation can enhance the transition probability. Moreover, for nonresonant couplings we show that the Zeno and anti-Zeno effects always appear sequentially in the evolution of the same system: there is Zeno effect in the short-time regime and anti-Zeno effect in the long-time regime.
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