Counterexamples to the Maximal p-Norm Multiplicativity Conjecture for all p > 1
Counterexamples to the Maximal p-Norm Multiplicativity Conjecture for all p > 1
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DOI:
10.1007/s00220-008-0624-0
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发表时间:
2008-11-01
影响因子:
2.4
通讯作者:
Winter, Andreas
中科院分区:
文献类型:
--
作者:
Hayden, Patrick;Winter, Andreas
For all p > 1, we demonstrate the existence of quantum channels with non-multiplicative maximal output p-norms. Equivalently, for all p > 1, the minimum output Renyi entropy of order p of a quantum channel is not additive. The violations found are large; in all cases, the minimum output Renyi entropy of order p for a product channel need not be significantly greater than the minimum output entropy of its individual factors. Since p = 1 corresponds to the von Neumann entropy, these counterexamples demonstrate that if the additivity conjecture of quantum information theory is true, it cannot be proved as a consequence of any channel-independent guarantee of maximal p-norm multiplicativity. We also show that a class of channels previously studied in the context of approximate encryption lead to counterexamples for all p > 2.