  In this work, we study transfer of coherence matrices along spin-1/2 chains
of various length. Unlike higher order coherence matrices, 0-order coherence
matrix can be perfectly transferred if its elements are properly fixed. In
certain cases, to provide the perfect transfer, an extended receiver together
with optimized its unitary transformation has to be included into the protocol.
In this work, the asymptotic perfectly transferable 0-order coherence matrix
for an infinitely long chain is considered and deviation of a perfectly
transferred state from this asymptotic state is studied as a function of the
chain length for various sizes of the extended receiver. The problem of
arbitrary parameter transfer via the nondiagonal elements of the 0-order
coherence matrix is also considered and optimized using the unitary
transformation of the extended receiver.

Quantum Physics