Free coherent spinons in quantum square ice

TL;DR

This paper demonstrates the existence of coherent, freely propagating spinon quasiparticles in quantum square ice, supported by exact results and dynamic structure factor analysis, revealing fundamental quantum excitations in frustrated magnetic systems.

Contribution

It provides the first unbiased evidence of coherent spinon quasiparticles in quantum square ice through exact calculations and dynamic response analysis.

Findings

Dispersive lower bound of spinon response is observed

Coherent spinon quasiparticles propagate freely

Dynamic structure factor reveals spinon dispersion

Abstract

We investigate the quantum dynamics of monopole-like excitations in quantum square ice, as captured by the strongly anisotropic spin-1/2 XXZ model on the checkerboard lattice. We obtain exact results for excitation dynamics in both analytically solvable effective models and a fully interacting model of quantum square ice on finite clusters. We find that the dispersive lower bound of the dynamic response of freely propagating spinons is recovered in the dynamic structure factor of the interacting system, yielding a marked fingerprint of coherent spinon dispersion. Our results provide unbiased evidence for the formation of coherent quasiparticles propagating freely in the correlated "vacuum" of quantum square ice.