Fractionalization Signatures in the Dynamics of Quantum Spin Liquids

TL;DR

This paper explores how fractionalized particles in quantum spin liquids can be identified through dynamical correlations, using advanced computational methods to analyze the Kitaev honeycomb model under magnetic fields.

Contribution

It introduces a combined analytical and numerical approach to detect fractionalization signatures in non-integrable quantum spin liquids, clarifying the nature of the intermediate gapless phase.

Findings

Correlations distinguish Majorana fermions and Z2 fluxes in different phases.

The intermediate gapless phase is identified as a Majorana metal.

Dynamical signatures effectively reveal fractionalization in complex quantum states.

Abstract

We investigate the signatures of fractionalization in quantum spin liquids by studying different phases of the Kitaev honeycomb model in the presence of an out-of-plane magnetic field through which the model becomes non-integrable. Using the infinite projected entangled pair states (iPEPS) ansatz, along with analytical calculations and exact diagonalization, we calculate dynamical signatures of fractionalized particles through spin-spin and dimer-dimer correlations. Our analysis demonstrates the ability of these correlations to discern distinct fractionalized quantum sectors, namely Majorana fermions and the emergent $Z_2$ fluxes, in both the chiral spin liquid (CSL) phase under weak field and the emergent intermediate gapless phase (IGP) under moderate field. Importantly, our calculation reveals the nature of IGP observed at moderate fields, a region of ongoing debate, indicating that this phase is a Majorana metal induced by strong flux fluctuations.