  A novel method of purification, purification through Zeno-like measurements
[H. Nakazato, T. Takazawa, and K. Yuasa, Phys. Rev. Lett. 90, 060401 (2003)],
is discussed extensively and applied to a few simple qubit systems. It is
explicitly demonstrated how it works and how it is optimized. As possible
applications, schemes for initialization of multiple qubits and entanglement
purification are presented, and their efficiency is investigated in detail.
Simplicity and flexibility of the idea allow us to apply it to various kinds of
settings in quantum information and computation, and would provide us with
useful and practical methods of state preparation.
