Entanglement Entropy of the Low-Lying Excited States and Critical Properties of an Exactly Solvable Two-Leg Spin Ladder with Three-Spin Interactions

TL;DR

This paper analytically studies an exactly solvable two-leg spin ladder with three-spin interactions, analyzing entanglement entropy and critical properties, confirming conformal field theory predictions and identifying the model's universality class.

Contribution

It provides an exact analysis of the entanglement entropy and critical behavior of a novel spin ladder model with three-spin interactions, linking it to conformal field theory.

Findings

Central charge c=1 confirmed for the model

Finite-size corrections match conformal field theory predictions

Entanglement entropy of excited states analyzed

Abstract

In this work, we investigate an exactly solvable two-leg spin ladder with three-spin interactions. We obtain analytically the finite-size corrections of the low-lying energies and determine the central charge as well as the scaling dimensions. The model considered in this work has the same universality class of critical behavior of the XX chain with central charge c=1. By using the correlation matrix method, we also study the finite-size corrections of the Renyi entropy of the ground state and of the excited states. Our results are in agreement with the predictions of the conformal field theory.