Invitation to Quantum Informatics

The present text covers the connections between information and its processing on the one hand, and physics on the other. In the spirit of Rolf Landauer's slogan "Information is physical," consequences of physical laws for communication and computation are discussed, e.g. the second law of thermodynamics. In the second part, the pessimism of the first part is overcome and new possibilities offered by the laws of quantum physics for information processing are discussed: cryptography, teleportation, dense coding, and algorithms such as Grover's. The culmination point is Shor's miraculous method for efficiently factoring integers. The epilogue is an extended version of the third author's closing lecture of the seminar "Information & Physics (& Science Sociology)," in which Landauer's sentence is contrasted with John Archibald Wheeler's "It from Bit."