Remote information concentration via \(W\) state: reverse of ancilla-free phase-covariant telecloning
In this paper, we investigate generalized remote information concentration as the reverse process of ancilla-free phase-covariant telecloning (AFPCT) which is different from the reverse process of optimal universal telecloning. It is shown that the quantum information via \(1\rightarrow 2\) AEPCT procedure can be remotely concentrated back to a single qubit with a certain probability by utilizing (non-)maximally entangled \(W\) states as quantum channels. Our protocols are the generalization of Wangs scheme (Open J Microphys 3:1821. doi:10.?4236/?ojm.?2013.?31004, 2013). And von Neumann measure and positive operator-valued measurement are performed in the maximal and non-maximal cases respectively. Relatively the former, the dimension of measurement space in the latter is greatly reduced. It makes the physical realization easier and suitable.
remote information concentration ancilla-free phase-covariant teleclong three-qubit asymmetric entangled \(w\) nonmaximally entangled \(w\) state projective measurement povm