608 citations · 2.5k across the 47 of their papers we have counts for
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Multiplicativity properties of entrywise positive maps
Christopher King, Michael Nathanson, Mary Beth Ruskai
Multiplicativity of certain maximal p -> q norms of a tensor product of linear maps on matrix algebras is proved in situations in which the condition of complete positivity (CP) is…
Conditions for the multiplicativity of maximal l_p-norms of channels for fixed integer p
Vittorio Giovannetti, Seth Lloyd, Mary Beth Ruskai
We introduce a condition for memoryless quantum channels which, when satisfied guarantees the multiplicativity of the maximal l_p-norm with p a fixed integer. By applying the condi…
Lieb's simple proof of concavity of Tr A^p K^* B^(1-p) K and remarks on related inequalities
Mary Beth Ruskai
A simple, self-contained proof is presented for the concavity of the map (A,B) --> Tr(A^p K^* B^(1-p) K). The author makes no claim to originality; this note gives Lieb's original…
Qubit Channels Which Require Four Inputs to Achieve Capacity: Implications for Additivity Conjectures
Masahito Hayashi, Hiroshi Imai, Keiji Matsumoto +2
An example is given of a qubit quantum channel which requires four inputs to maximize the Holevo capacity. The example is one of a family of channels which are related to 3-state c…
Comments on multiplicativity of maximal p-norms when p = 2
Christopher King, Mary Beth Ruskai
We consider the maximal p-norm associated with a completely positive map and the question of its multiplicativity under tensor products. We give a condition under which this multip…