Entanglement Density Gradient Mapping (EDGM): A New Geometric Perspective on Quantum Correlations
Jincheng Zhang
Abstract
Quantum entanglement is traditionally quantified by scalar measures such as entanglement entropy, which capture the amount of quantum correlation between subsystems but obscure its spatial distribution within many‑body states. In this work we introduce the concept of Entanglement Density Gradient Mapping (EDGM), a framework that treats entanglement as a spatially varying field. By defining an entanglement density S_E(r) over the spatial coordinates of a quantum system, we construct the gradient operator nabla S_E(r) to characterize how entanglement changes locally. This gradient field reveals rich geometric structures that are invisible to conventional scalar measures. We develop the mathematical formalism of EDGM, derive its transformation properties under local unitary operations, and show that it satisfies a continuity equation analogous to conserved currents in field theory. The EDGM framework naturally leads to a quantum information geometry where entanglement gradients define a metric on the manifold of many‑body states. We discuss potential applications of EDGM in understanding quantum phase transitions, designing entanglement‑based protocols for quantum simulation, and guiding the development of large‑scale quantum simulators. The approach offers a new lens for exploring the deep connection between spatial entanglement patterns and the geometry of quantum information, opening avenues for theoretical advances that could inform future experimental realizations of highly entangled states.