QUROPE Quantum Information Processing and Communication in Europe

We point out a contrasting role the entanglement plays in communication and estimation scenarios.
In the first case it brings noticeable benefits at the measurement stage (output super-additvity),
whereas in the latter it is the entanglement of the input probes that enables significant performance
enhancement (input super-additvity). We identify a weak estimation regime where a strong connection
between concepts crucial to the two fields is demonstrated; the accessible information and the
Holevo quantity on one side and the quantum Fisher information related quantities on the other.