  We perform a numerical study of the distribution of entanglement on a
real-world fiber grid connecting the German cities of Bonn and Berlin. The
connection is realized using a chain of processing-node quantum repeaters
spanning roughly 900 kilometers. We investigate how minimal hardware
requirements depend on the target application, as well as on the number of
repeaters in the chain. We find that requirements for blind quantum computing
are markedly different than those for quantum key distribution, with the
required coherence time being around two and a half times larger for the
former. Further, we observe a trade-off regarding how target secret-key rates
are achieved when using different numbers of repeaters: comparatively
low-quality entangled states generated at a high rate are preferred for higher
numbers of repeaters, whereas comparatively high-quality states generated at a
lower rate are favored for lower numbers of repeaters. To obtain our results we
employ an extensive simulation framework implemented using NetSquid, a
discrete-event simulator for quantum networks. These are combined with an
optimization methodology based on genetic algorithms to determine minimal
hardware requirements.
