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The power of reduced quantum states

N. Linden·S. Popescu·W. K. Wootters
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Abstract

In a system of n quantum particles, we define a measure of the degree of irreducible n-way correlation, by which we mean the correlation that cannot be accounted for by looking at the states of (n-1) particles. In the case of almost all pure states of three qubits we show that there is no such correlation: almost every pure state of three qubits is completely determined by its two-particle reduced density matrices.

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N. Linden, S. Popescu, W. K. Wootters. 2002-07-18. The power of reduced quantum states. https://arxiv.org/abs/quant-ph/0207109

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