  Strong correlations in matter promote a landscape of ground states and
associated quantum critical points. For metallic systems, there is increasing
recognition that the quantum criticality goes beyond the standard Landau
framework and, thus, novel means are needed to characterize the quantum
critical fluid. Here we do so by studying the entanglement properties near a
quantum critical point of a strongly correlated metal. We calculate the quantum
Fisher information of an Anderson/Kondo lattice model across its Kondo
destruction quantum critical point. The quantum Fisher information of the spin
degree of freedom peaks at the quantum critical point and indicates a strongly
entangled ground state. Our results are supported by the quantum Fisher
information extracted from inelastic neutron scattering measurements in quantum
critical heavy fermion metals. Our work opens a new avenue to advance the
understanding of metallic quantum criticality in a broad range of strongly
correlated systems, and points to a new regime of quantum matter to realize
amplified entanglement.
