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arXiv:quant-ph/0502025 · International Journal of Quantum Information

UNITARY LOCAL INVARIANCE

Matteo G. A. Paris

Published Dec 1, 2005• 7 citations
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Abstract

We address unitary local (UL) invariance of bipartite pure states. Given a bipartite state |Ψ〉〉 = ∑ij ψij |i〉1 ⊗ |j〉2 the complete characterization of the class of local unitaries U1 ⊗ U2 for which U1 ⊗ U2|Ψ〉〉 = |Ψ〉〉 is obtained. The two relevant parameters are the rank of the matrix Ψ, [Ψ]ij = ψij, and the number of its equal singular values, i.e. the degeneracy of the eigenvalues of the partial traces of |Ψ〉〉.

DOI
10.1142/s0219749905001523

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