We describe a unified framework of phase-covariant multiuser quantum transformations for d-dimensional quantum systems. We derive the optimal phase-covariant cloning and transposition transformations for multiphase states. We show that for some particular relations between the input and output number of copies, they correspond to economical transformations, which can be achieved without the need of auxiliary systems. We prove a relation between the optimal phase-covariant cloning and transposition maps and optimal estimation of multiple phases for equatorial states.
© 2007 Optical Society of America
Original Manuscript: May 19, 2006
Manuscript Accepted: June 5, 2006
Published: January 26, 2007
Francesco Buscemi, Giacomo Mauro D'Ariano, and Chiara Macchiavello, "Economical realization of phase-covariant devices in arbitrary dimensions (Invited)," J. Opt. Soc. Am. B 24, 363-370 (2007)