Achieving the Holevo bound via sequential measurements

Abstract

We present a decoding procedure to transmit classical information in a quantum channel which, saturating asymptotically the Holevo bound, achieves the optimal rate of the communication line. In contrast to previous proposals, it is based on performing a sequence of projective yes-no measurements which in N steps determines which codeword was sent by the sender (N being the number of the codewords). Our analysis shows that, as long as N is below the limit imposed by the Holevo bound, the error probability can be sent to zero asymptotically in the length of the codewords.