The influence of boundary conditions on the emergence of non-compact degrees of freedom in the scaling limit of integrable lattice models

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Original languageEnglish
QualificationDoctor rerum naturalium
Awarding Institution
Supervised by
Thesis sponsors
  • German Research Foundation (DFG)
Date of Award11 Jun 2024
Publication statusPublished - 2024

Abstract

One-dimensional critical integrable lattice models with a finite-dimensional degree of freedom attached to each lattice site can exhibit the remarkable phenomenon of the emergence of continuous degrees of freedom in the scaling limit. The most studied system in which this occurrence has been observed is the staggered six-vertex model with twisted boundary conditions. Here, we study the influence of different boundary conditions and higher-rank generalisations on/of this model. Our analysis is based on the Bethe ansatz and the formulation of a conserved quantity --- the so-called quasi-momentum --- which parametrises the non-compact degree of freedom directly on the lattice. Moreover, we carry over the powerful approach of the correspondence between ordinary differential equations and integrable quantum field theories to the case of open boundary conditions.
Using this methodology, we can fully classify the scaling limit of the alternating six-vertex model with \(U_q(\mathfrak{sl}(2))\) boundary conditions. Furthermore, we demonstrate the incompatibility of antidiagonal boundary conditions with a non-compact degree of freedom in the scaling limit. Finally, we provide numerical evidence that the higher rank generalisation, the \(D^{(2)}_3\) model, possesses two independent continuous components.

Keywords

    Integrability, Bethe ansatz, six-vertex model, boundary conditions, scaling limit, lattice models, conformal field theory, critical exponents

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title = "The influence of boundary conditions on the emergence of non-compact degrees of freedom in the scaling limit of integrable lattice models",
abstract = "One-dimensional critical integrable lattice models with a finite-dimensional degree of freedom attached to each lattice site can exhibit the remarkable phenomenon of the emergence of continuous degrees of freedom in the scaling limit. The most studied system in which this occurrence has been observed is the staggered six-vertex model with twisted boundary conditions. Here, we study the influence of different boundary conditions and higher-rank generalisations on/of this model. Our analysis is based on the Bethe ansatz and the formulation of a conserved quantity --- the so-called quasi-momentum --- which parametrises the non-compact degree of freedom directly on the lattice. Moreover, we carry over the powerful approach of the correspondence between ordinary differential equations and integrable quantum field theories to the case of open boundary conditions. Using this methodology, we can fully classify the scaling limit of the alternating six-vertex model with \(U_q(\mathfrak{sl}(2))\) boundary conditions. Furthermore, we demonstrate the incompatibility of antidiagonal boundary conditions with a non-compact degree of freedom in the scaling limit. Finally, we provide numerical evidence that the higher rank generalisation, the \(D^{(2)}_3\) model, possesses two independent continuous components. ",
keywords = "Integrability, Bethe ansatz, six-vertex model, boundary conditions, scaling limit, lattice models, conformal field theory, critical exponents",
author = "Sascha Gehrmann",
year = "2024",
doi = "10.15488/17537",
language = "English",
school = "Leibniz University Hannover",

}

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TY - BOOK

T1 - The influence of boundary conditions on the emergence of non-compact degrees of freedom in the scaling limit of integrable lattice models

AU - Gehrmann, Sascha

PY - 2024

Y1 - 2024

N2 - One-dimensional critical integrable lattice models with a finite-dimensional degree of freedom attached to each lattice site can exhibit the remarkable phenomenon of the emergence of continuous degrees of freedom in the scaling limit. The most studied system in which this occurrence has been observed is the staggered six-vertex model with twisted boundary conditions. Here, we study the influence of different boundary conditions and higher-rank generalisations on/of this model. Our analysis is based on the Bethe ansatz and the formulation of a conserved quantity --- the so-called quasi-momentum --- which parametrises the non-compact degree of freedom directly on the lattice. Moreover, we carry over the powerful approach of the correspondence between ordinary differential equations and integrable quantum field theories to the case of open boundary conditions. Using this methodology, we can fully classify the scaling limit of the alternating six-vertex model with \(U_q(\mathfrak{sl}(2))\) boundary conditions. Furthermore, we demonstrate the incompatibility of antidiagonal boundary conditions with a non-compact degree of freedom in the scaling limit. Finally, we provide numerical evidence that the higher rank generalisation, the \(D^{(2)}_3\) model, possesses two independent continuous components.

AB - One-dimensional critical integrable lattice models with a finite-dimensional degree of freedom attached to each lattice site can exhibit the remarkable phenomenon of the emergence of continuous degrees of freedom in the scaling limit. The most studied system in which this occurrence has been observed is the staggered six-vertex model with twisted boundary conditions. Here, we study the influence of different boundary conditions and higher-rank generalisations on/of this model. Our analysis is based on the Bethe ansatz and the formulation of a conserved quantity --- the so-called quasi-momentum --- which parametrises the non-compact degree of freedom directly on the lattice. Moreover, we carry over the powerful approach of the correspondence between ordinary differential equations and integrable quantum field theories to the case of open boundary conditions. Using this methodology, we can fully classify the scaling limit of the alternating six-vertex model with \(U_q(\mathfrak{sl}(2))\) boundary conditions. Furthermore, we demonstrate the incompatibility of antidiagonal boundary conditions with a non-compact degree of freedom in the scaling limit. Finally, we provide numerical evidence that the higher rank generalisation, the \(D^{(2)}_3\) model, possesses two independent continuous components.

KW - Integrability, Bethe ansatz, six-vertex model, boundary conditions, scaling limit, lattice models, conformal field theory, critical exponents

U2 - 10.15488/17537

DO - 10.15488/17537

M3 - Doctoral thesis

ER -

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