Controlled and combined remote implementations of partially unknown   quantum operations of multiqubits using GHZ states
  We propose and prove protocols of controlled and combined remote implementations of partially unknown quantum operations belonging to the restricted sets [An Min Wang: PRA, \textbf{74}, 032317(2006)] using GHZ states. We detailedly describe the protocols in the cases of one qubit, respectively, with one controller and with two senders. Then we extend the protocols to the cases of multiqubits with many controllers and two senders. Because our protocols have to demand the controller(s)'s startup and authorization or two senders together working and cooperations, the controlled and combined remote implementations of quantum operations definitely can enhance the security of remote quantum information processing and potentially have more applications. Moreover, our protocol with two senders is helpful to farthest arrive at the power of remote implementations of quantum operations in theory since the different senders perhaps have different operational resources and different operational rights in practice. 
An Min Wang