Impurity spin texture at a N\'eel-Valence Bond Solid critical point in $d=2$ SU(3) quantum antiferromagnets

TL;DR

This study investigates impurity effects at a quantum critical point in a 2D SU(3) antiferromagnet, providing insights into deconfined criticality and finite-size scaling behavior through quantum Monte Carlo simulations.

Contribution

It offers the first detailed analysis of impurity spin textures at a SU(3) deconfined critical point, highlighting finite-size scaling and potential marginal operators as N approaches 2.

Findings

Spin texture follows finite-size scaling at the critical point.

Significant subleading power-law finite size corrections are observed.

Evidence suggests the presence of marginal operators as N decreases to 2.

Abstract

We study the impurity physics at a continuous quantum phase transition from an SU(3) symmetric N\'eel ordered state to a valence bond solid state that breaks lattice symmetries, using quantum Monte Carlo techniques. This continuous transition is expected to be an example of `deconfined criticality' in an SU(3) symmetric system. We find that the spin-texture induced by a missing-spin defect at the transition takes on a finite-size scaling form consistent with expectations from standard scaling arguments at a scale-invariant quantum critical point, albeit with significant subleading power-law finite size corrections that we analyze in detail. Together with recently-found logarithmic violations of scaling at similar continuous transitions in the SU(2) case, our results provide indirect evidence for the existence of operators that become marginal as $N$ is reduced to 2 in the field theoretical description of these deconfined critical points.