Universal ratios along a line of critical points. The Ashkin–Teller model

2003/09/12 by Gesualdo Delfino, G. Delfino, P. Grinza +1
Mathematics · Physics and Astronomy · #Algebraic structures and combinatorial models #Spectroscopy and Quantum Chemical Studies #Theoretical and Computational Physics #cond-mat #hep-th

paper · pdf · doi:10.1016/j.nuclphysb.2004.01.007

published as Nucl.Phys. B682 (2004) 521-550 · 31 pages, latex

arxiv created 2003/09/12 · openalex publication_date 2004/01/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The two-dimensional Ashkin-Teller model provides the simplest example of a statistical system exhibiting a line of critical points along which the critical exponents vary continously. The scaling limit of both the paramagnetic and ferromagnetic phases separated by the critical line are described by the sine-Gordon quantum field theory in a given range of its dimensionless coupling. After computing the relevant matrix elements of the order and disorder operators in this integrable field theory, we determine the universal amplitude ratios along the critical line within the two-particle approximation in the form factor approach.

Citations

• Spin-spin correlation functions for the two-dimensional Ising model: Exact theory in the scaling region
• Asymptotic factorisation of form factors in two-dimensional quantum field theory
• Infinite conformal symmetry in two-dimensional quantum field theory
• Form factors of soliton-creating operators in the sine-Gordon model