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arXiv:1211.2328 · Physical Review A

Unitary invariants and classification of four-qubit states via negativity fonts

S. Shelly Sharma, Naresh Kumar Sharma

Published Feb 22, 2013• 10 citations
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Abstract

Local unitary invariance and the notion of negativity fonts are used as the principal tools to construct four-qubit invariants of degree 8, 12, and 24. A degree-8 polynomial invariant that is nonzero on pure four-qubit states with four-body quantum correlations and zero on all other states is identified. Classification of four-qubit states into seven major classes, using criteria based on the nature of correlations, is discussed.

DOI
10.1103/physreva.87.022335

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