Inhibition of Purification Processes through Zeno effect

It is shown that a generalized quantum Zeno effectbased on the introduction of a coherent coupling between several parts of a compound system can be responsible for neutralizing the effects of repeated measurements. To demonstrate this effect, we focus on a purification scheme based on iterated observations on an ancilla system put in interaction with the main one [Nakazato, Takazawa, Yuasa, Phys. Rev. Lett. {\bf 90}, 060401 (2003)]. We bring to light that a suitable Hilbert space partitioningdue to an appropriate interaction can eliminate the effects of repeated wave function collapsesthe purification scheme is based on.