Eluding Zeno effect via dephasing and detuning.

Abstract We analyze some variants of the Zeno effect in which the frequent observation of the population of an intermediate state does not prevent the transition of the system from the initial state to a certain final state. This is achieved by considering system observation involving suitably introduced phase shifts and detunings that leads to a rather rich measurement-induced dynamics by the alteration of the interference governing quantum evolution. For initial nonclassical states this includes entanglement as a way of evolution from the initial to the final state avoiding the intermediate state. This possibility is presented in a particular physical scenario in the form of a chain of three coupled harmonic oscillators, but we readily show then that the idea can be applied to other physical systems as well, such as atomic-level dynamics. These results are significant for a better knowledge of fundamental quantum concepts as well as regarding suitable applications in the proper control of quantum dynamics, as this is a key feature of modern applications of the quantum theory.