ABSTRACT
The theoretical toolbox has developed to describe a series of tasks, related to the transmission or extraction of information, which may be implemented with quantum continuous variable systems. This chapter opens with quantum teleportation, the transmission of a quantum state through shared quantum entanglement and classical communication, and determines certain thresholds it must attain to be considered genuinely quantum. It establishes the maximum classical communication capacity of a class of Gaussian channels and considers the optimal estimation of a dynamical parameter by using Gaussian states as probes. The chapter illustrates the fact that Gaussian states may be used for the secure distribution of a cryptographic key. Gaussian quantum key distribution has already been commercialised, and all the other techniques are gradually approaching the status of full-blown engineering technologies, which would arguably form the most convincing empirical evidence one may have in support of the underlying physical theory.
