  When applied to practical problems, the very laws of quantum mechanics can
provide a unique resource to beat the limits imposed by classical physics: this
is the case of quantum metrology and high-precision sensing. Here we review the
main results obtained in the recent years at the Quantum Technology Lab of the
Department of Physics "Aldo Pontremoli" of the University of Milan, also in
collaboration with national and international institutions. In particular we
focus on the application of continuous-variable optical quantum states and
operations to improve different field of research, ranging from interferometry
to more fundamental problems, such as the testing of quantum gravity.
