Concrete Quantum Channels and Algebraic Structure of Abstract Quantum Channels

Construction and testing of preconditioners of Toeplitz/block Toeplitz matrices using Korovkin's classic theorems of positive linear approximations are known. Later the map implementing preconditioners was observed to be a completely positive map, and this structure led to an abstract formulation of Korovkin-type theorems in a non-commutative setting. Interestingly enough, these preconditioner maps' properties satisfy the properties of an abstract quantum channel in quantum information theory. In this short article, this viewpoint is discussed by computing related quantities such as Kraus representation, channel capacity, fidelity etc. Moreover, the algebraic properties of the class of quantum channels are also discussed.