  Shannon's theory of information was built on the assumption that the
information carriers were classical systems. Its quantum counterpart, quantum
Shannon theory, explores the new possibilities arising when the information
carriers are quantum systems. Traditionally, quantum Shannon theory has
focussed on scenarios where the internal state of the information carriers is
quantum, while their trajectory is classical. Here we propose a second level of
quantisation where both the information and its propagation in spacetime is
treated quantum mechanically. The framework is illustrated with a number of
examples, showcasing some of the counterintuitive phenomena taking place when
information travels simultaneously through multiple transmission lines.
