The interest in a system often resides in the interplay among different parameters governing
its evolution. It is thus often required to access many of them at once for a complete
description. Assessing how quantum enhancement in such multiparameter estimation can
be achieved depends on understanding the many subtleties that come into play:
establishing solid foundations is key to delivering future technology for this task. In this
article we discuss the state of the art of quantum multiparameter estimation, with a particular …