Maximally genuine multipartite entangled mixed X-states of N-qubits
Abstract
For every possible spectrum of -dimensional density operators, we construct an -qubit X-state of same spectrum and maximal genuine multipartite (GM-) concurrence, hence characterizing a global unitary transformation that --- constrained to output X-states --- maximizes the GM-concurrence of an arbitrary input mixed state of qubits. We also apply semidefinite programming methods to obtain -qubit X-states with maximal GM-concurrence for a given purity and to provide an alternative proof of optimality of a recently proposed set of density matrices for the role, the so-called X-MEMS. Furthermore, we introduce a numerical strategy to tailor a quantum operation that converts between any two given density matrices using a relatively small number of Kraus operators. We apply our strategy to design short operator-sum representations for the transformation between any given -qubit mixed state and a corresponding X-MEMS of same purity.
Keywords
Cite
@article{arxiv.1502.02082,
title = {Maximally genuine multipartite entangled mixed X-states of N-qubits},
author = {Paulo E. M. F. Mendonca and Seyed Mohammad Hashemi Rafsanjani and Diógenes Galetti and Marcelo A. Marchiolli},
journal= {arXiv preprint arXiv:1502.02082},
year = {2015}
}
Comments
22 pages, 2 figures. v2 (published version): connection with "biseparability from spectrum" dropped from the concluding remarks since, in the last paragraph os Sec. 3, an argument was included to demonstrate that N-qubit X-MEMS are generally not N-qubit MEMS