On the minimum number of unitaries needed to describe a random-unitary channel
arXiv:quant-ph/0607034 · doi:10.1016/j.physleta.2006.08.038
Abstract
We provide, in an extremely simple way, an upper bound to the minimum number of unitary operators describing a general random-unitary channel.
Final version accepted for publication. One wrong equation has been corrected, two notes and one reference have been added