Emergent infinite-randomness fixed points from the extensive random bipartitions of the spin-1 Affleck-Kennedy-Lieb-Tasaki topological state

TL;DR

This paper shows that an infinite-randomness fixed point can emerge in a spin-1 chain through extensive bipartitions, revealing critical boundary theories and entanglement properties related to topological phases.

Contribution

It demonstrates the emergence of an infinite-randomness fixed point from extensive bipartitions of a spin-1 AKLT chain, linking entanglement features to critical boundary theories.

Findings

Nested entanglement entropy scales logarithmically with an effective central charge ~0.72

Infinite-randomness fixed point emerges from bipartitions of the spin-1 AKLT chain

Analysis of phase boundaries and Griffiths phases in disordered spin-1 chains

Abstract

Quantum entanglement under an extensive bipartition can reveal the critical boundary theory of a topological phase in the parameter space. In this study we demonstrate that the infinite-randomness fixed point for spin-1/2 degrees of freedom can emerge from an extensive random bipartition of the spin-1 Affleck-Kennedy-Lieb-Tasaki chain. The nested entanglement entropy of the ground state of the reduced density matrix exhibits a logarithmic scaling with an effective central charge $\tilde{c} = 0.72 \pm 0.02 \approx \ln 2$. We further discuss, in the language of bulk quantum entanglement, how to understand all phase boundaries and the surrounding Griffiths phases for the antiferromagnetic Heisenberg spin-1 chain with quenched disorder and dimerization.