Non-Hermiticity-induced quantum control of localization in quantum walks

Non-Hermiticity-induced quantum control is an unique phenomenon, which cannot be observed in Hermitian quantum systems. Here we study the quantum control of localization in non-Hermitian QW systems. When a phase defect is introduced to a specific site of non-Hermitian QW, the walker will not only be localized at the site of phase defect but also at its neighboring sites. Moreover, we find that as the system transforms from the PT-symmetry-unbroken regime to PT-symmetry-broken regime, most of probability distributions can be found at the positions far away from the phase defect in a long period of time. Our discoveries about the control of walker in non-Hermitian QW can provide valuable references for the study of quantum search in dissipative quantum systems.