C. Adami and N.J. Cerf. Von Neumann capacity of noisy quantum channels. Phys. Rev. A 56, no. 5, 3470-3483 (1997).  Home/Search   Document Not in Database   Summary   APS   Related Articles   Check

....is the final entropy of the environment. Now we can define (p, T) S(p) S(T ) S( T) 6.27) which is the quantum analog of the mutual information given in Equation (6. 21) It has a number of nice properties, in particular positivity, concavity with respect to the input state and additivity [2] and its maximum with respect to p coincides actually with Ce (T) 18] THEOREM 6.2.3 The entanglement assisted capacity Ce(T) of a quantum channel T: B (J( B (J( is given by Ce (T) sup I (p, T) 6.28) where the supremum is taken over all input states p B (J( Due to the nice ....

C. Adami and N.J. Cerf. Von Neumann capacity of noisy quantum channels. Phys. Rev. A 56, no. 5, 3470-3483 (1997).

....source satisfying the QAEP and having entropy less than the capacity may be sent with high entanglement fidelity, so that quantum entropy and entanglement capacity parallel classical entropy and capacity in this respect. This chapter represents joint work with E. Knill and M. A. Nielsen. 151 In [62] Adami and Cerf express the view that Whether a capacity can be defined consistently that characterizes the purely quantum component of a channel is an open question. In my view, the pure state capacity defined below and in earlier papers is just such a consistently defined capacity, and the ....

C. Adami and N. Cerf, "Von Neumann capacity of a noisy quantum channel," Physical Review A, vol. 56, pp. 3470, 1997. 212

....from the expression a maximization over encodings, con rming an earlier conjecture. The conjecture has also been con rmed by [21] but the result that any source that may be transmitted may be transmitted using partially isometric encodings is slightly stronger than that obtained in [21] In [22] Adami and Cerf express the view that Whether a capacity can be de ned consistently that characterizes the purely quantum component of a channel is an open question. In our view, the pure state capacity de ned below and in earlier papers is just such a consistently de ned capacity, and the ....

C. Adami and N. Cerf, \Von Neumann capacity of a noisy quantum channel," Physical Review A, vol. 56, pp. 3470, 1997.

.... (which is charcterized by its attention to entanglement) poses many new and beautiful, and also very difficult problems, the present note is concerned wholly with the former area (though it is by now not altogether clear how to separate these two worlds, cf. e.g. opinion uttered by Adami and Cerf [5]) We take the view that classical quantum problems are those in which classical information has to be stored in or sent trough some quantum system. Examples from recent work are the determination of the quantum channel capacity for fixed input states [6 8] quantum cryptographic protocols ....

C. Adami, N. J. Cerf, "On the von Neumann capacity of noisy quantum channels", Phys. Rev. A 56,5(1997), 3470--3483

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