Characterizing the Ground State in Many-body Systems Using Multiple Concurrences

Abstract We introduce a framework for characterizing many-body ground states based on the interplay of different types of concurrences. Rather than relying on a single entanglement measure, we show that the relative magnitude and scaling of spin and orbital concurrences provide a physically transparent classification of the ground state. Using the single-site Anderson model as a minimal and exactly constrained testbed, we show that spin-singlet formation and orbital superposition contribute in qualitatively different ways, leading to distinct ground-state spectral weights characterized by dominant spin or orbital degrees of freedom. Our results establish concurrences as diagnostic tools that provide a transparent characterization of the ground-state structure within this minimal setting, and suggest a possible strategy for identifying the nature of quantum superposition in more complex many-body systems.