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arXiv · 2308.02811

Boundary effects and the stability of the low energy spectrum of the AKLT model

Simone Del Vecchio·Jürg Fröhlich·Alessandro Pizzo·Alessio Ranallo
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Abstract

In this paper we study the low-lying spectrum of the AKLT model perturbed by small, finite-range potentials and with open boundary conditions imposed at the edges of the chain. Our analysis is based on the \emph{local, iterative Lie Schwinger block-diagonalization method} which allows us to control small interaction terms localized near the boundary of the chain that are responsible for the possible splitting of the ground-state energy of the AKLT Hamiltonian into energy levels separated by small gaps. This improves earlier results concerning the persistence of the so called \emph{bulk} gap in these models, besides illustrating the power of our general methods in a non-trivial application.

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Simone Del Vecchio, Jürg Fröhlich, Alessandro Pizzo, Alessio Ranallo. 2023-08-05. Boundary effects and the stability of the low energy spectrum of the AKLT model. https://arxiv.org/abs/2308.02811

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