  A system of interacting qubits can be viewed as a non-i.i.d quantum
information source. A possible model of such a source is provided by a quantum
spin system, in which spin-1/2 particles located at sites of a lattice interact
with each other. We establish the limit for the compression of information from
such a source and show that asymptotically it is given by the von Neumann
entropy rate. Our result can be viewed as a quantum analog of Shannon's
noiseless coding theorem for a class of non - i.i.d. quantum information
sources.
