Maximally genuine multipartite entangled mixed X-states of N-qubits

• Autor(a) principal: Mendonca, Paulo E. M. F.
• Data de Publicação: 2015
• Outros Autores: Rafsanjani, Seyed Mohammad Hashemi, Galetti, Diogenes [UNESP], Marchiolli, Marcelo A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://iopscience.iop.org/article/10.1088/1751-8113/48/21/215304/meta;jsessionid=13A8C4D8E6CCFDF9ECF6EF03978759D1.c1; http://hdl.handle.net/11449/128955
• topic: Entanglement; Genuine multipartite concurrence; N-qubit X-states

For every possible spectrum of 2(N)-dimensional density operators, we construct an N-qubit X-state of the 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 N qubits. We also apply semidefinite programming methods to obtain N-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 purpose, 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 N-qubit mixed state and a corresponding X-MEMS of the same purity.