Weak measurement-based decoherence control of quantum systems

Properties and potential applications of weak measurement are investigated.First,a kind of positive operator-valued measurement is defined,and a sufficient condition is deduced for weak measurement from the view of linear normed space.Secondly,the applicability of weak measurement is discussed.It is shown that weak measurement is applicable not only to a set of identical quantum systems,but also to a single quantum system if any measurement operator can be selectively implemented.Finally,the effects of weak measurement on different quantum systems are studied.For a set of identical quantum systems,weak measurement affects states as a dephasing process.However,for a two-level single quantum system,it can be used to inhibit dephasing and to depolarization processes.