Quantum Zeno effect and the impossibility of determining the quantum state of a single system

The quantum Zeno effect of a single system is the effect of a series of measurements on the unitary time evolution of the system and on the ability to monitor this time evolution using the measurement results. This effect is shown to be equivalent to that of the indetermination of the quantum state of a single system [Phys. Rev. Lett. 74, 4106 (1995)], in which one considers the statistics of the results of a series of measurements performed on a single system, with no time evolution in between successive measurements.