Edge of entanglement in nonergodic states: A complexity parameter formulation.

Shekhar, Devanshu; Shukla, Pragya · Phys Rev E · 2025

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Abstract

We analyze the subsystem size scaling of the entanglement entropy of a nonergodic pure state that can be described by a multiparametric Gaussian ensemble of complex matrices in a bipartite basis. Our analysis indicates, for a given set of global constraints, the existence of an infinite number of universality classes of local complexity, characterized by the complexity parameter, for which the entanglement entropy reveals a universal scaling with subsystem size. A rescaling of the complexity parameter helps us to identify the critical regime for the entanglement entropy of a broad range of pure nonergodic states.