Generating random quantum channels

Several techniques of generating random quantum channels, which act on the set $d$-dimensional states, are investigated. We present three approaches to problem sampling channels and show under conditions they become mathematically equivalent, lead uniform, Lebesgue measure convex operations. compare their advantages computational complexity demonstrate them is particularly suitable for numerical investigations. Additional results focus spectral gap other properties invariant states. compute mean values several quantities characterizing a given channel, including its unitarity, average output purity $2$-norm coherence averaged over entire with respect uniform measure. An ensemble classical stochastic matrices obtained due super-decoherence maps analyzed studied using Bloch representation probability vector.