Intertwined orders in a quantum-entangled metal

Entanglement underpins quantum computing and information processing, yet its quantitative characterization in correlated materials remains an outstanding challenge. Here we report a highly entangled electronic phase near a quantum metal–insulator transition identified by resonant inelastic X-ray scattering interferometry. Entanglement extending across atomic sites generates distinct interference patterns that are accurately captured by theoretical modelling, enabling quantitative reconstruction of the entanglement spectrum and microscopic resolution of the underlying quantum states. In the pyrochlore iridate Nd$_2$Ir$_2$O$_7$, pronounced quantum fluctuations of spin, orbital and charge persist within the long-range ‘all-in-all-out’ antiferromagnetic order. The observed entanglement signatures indicate the coexistence of multiple symmetry-breaking orders, supported by complementary Raman spectroscopy investigations. A two-magnon bound state appears below the lowest single-magnon excitation energy, which together with split phonon modes indicates a cubic symmetry breaking of magnetic origin coexisting with the all-in-all-out order. These findings establish a quantitative framework linking quantum entanglement to emergent unconventional orders.