4 Distinguishability and information
4.1 Quantum communication
We now return our focus to the idea of information. A quantum system may be used as a medium for the storage, transmission, and retrieval of information. The rules of quantum physics have implications for this process. In a larger sense, too, the state vector |ψ of a quantum system provides information about the outcomes of possible future measurements. In this chapter, we will use the quantum theory developed so far to explore these issues.
We introduced the notion of information ...