Information propagation in a quantum system: examples of open spin-1/2 chains

If information is encoded into the state of the subsystem S of a quantum system initially (at t = 0), then it becomes distributed over the whole quantum system at t > 0 due to quantum interactions. Consequently, this information, in general, can be extracted, either completely or partially, from any subsystem of a quantum system. We suggest a method of extraction of information, which is based on the polarization measurements on the receiver R.