CONTROLLED DENSE CODING VIA GENERALIZED MEASUREMENT
Abstract
A scheme of realizing controlled dense coding via generalized measurement was presented. In this protocol, the supervisor can control the entanglement between the sender and the receiver and then the average amount of information transmitted from the sender to the receiver by only adjusting measurement angle θ. It is shown that when the quantum channel was a GHZ state, the entanglement and the average amount of information are determined by supervisor's measurement angle θ only; whereas when the quantum channel was a GHZ-class state, those are determined not only by supervisor's measurement angle θ but also the minimal coefficient of the GHZ-class state.