Quantum Zeno Subspaces

The quantum Zeno effect is recast in terms of an adiabatic theorem when the measurement is described as the dynamical coupling to another quantum system that plays the role of apparatus. A few significant examples are proposed and their practical relevance discussed. We also focus on decoherence-free subspaces.

Figure 1

The Hilbert space of the system: an effective superselection rule appears as the coupling $K$ to the apparatus is increased.