Entanglement signatures of emergent Dirac fermions: kagome spin liquid & quantum criticality

TL;DR

This paper uses entanglement entropy analysis via numerical methods to identify signatures of emergent Dirac fermions in kagome quantum spin liquids and quantum critical points, providing a new diagnostic approach.

Contribution

It introduces a numerical Aharonov-Bohm experiment to detect entanglement signatures of fractionalized excitations in kagome QSLs and benchmarks the method on a quantum critical point.

Findings

Universal entanglement features of Dirac spinons identified

Method successfully distinguishes quantum spin liquid states

Benchmark results on Dirac semimetal and charge order transition

Abstract

Quantum spin liquids (QSL) are exotic phases of matter that host fractionalized excitations. It is difficult for local probes to characterize QSL, whereas quantum entanglement can serve as a powerful diagnostic tool due to its non-locality. The kagome antiferromagnetic Heisenberg model is one of the most studied and experimentally relevant models for QSL, but its solution remains under debate. Here, we perform a numerical Aharonov-Bohm experiment on this model and uncover universal features of the entanglement entropy. By means of the density-matrix renormalization group, we reveal the entanglement signatures of emergent Dirac spinons, which are the fractionalized excitations of the QSL. This scheme provides qualitative insights into the nature of kagome QSL, and can be used to study other quantum states of matter. As a concrete example, we also benchmark our methods on an interacting quantum critical point between a Dirac semimetal and a charge ordered phase.