Some features of the State-space trajectories followed by robust entangled four-qubit states during decoherence

A.P.MAJTEY; A. BORRAS; A.R. PLASTINO; M.CASAS; A. PLASTINO

INTERNATIONAL JOURNAL OF QUANTUM INFORMATION

WORLD SCIENTIFIC PUBL CO PTE LTD

Año: 2010 vol. 8 p. 505 - 515

0219-7499

     In a recent work (Borras et al., Phys. Rev. A 79 (2009) 022108), we have determined, for various decoherence channels, four-qubit initial states exhibiting the most robust possible entanglement. Here, we explore some geometrical features of the trajectories in state space generated by the decoherence process, connecting the initially robust pure state with the completely decohered mixed state obtained at the end of the evolution. We characterize these trajectories by recourse to the distance between the concomitant time-dependent mixed state and di®erent reference stateset al., Phys. Rev. A 79 (2009) 022108), we have determined, for various decoherence channels, four-qubit initial states exhibiting the most robust possible entanglement. Here, we explore some geometrical features of the trajectories in state space generated by the decoherence process, connecting the initially robust pure state with the completely decohered mixed state obtained at the end of the evolution. We characterize these trajectories by recourse to the distance between the concomitant time-dependent mixed state and di®erent reference states