Flow Equation Solution for the Weak- to Strong-Coupling Crossover in the Sine-Gordon Model

1999/08/31 by Stefan Kehrein · 5 citations
Mathematics · Physics and Astronomy · #Algebraic structures and combinatorial models #Nonlinear Waves and Solitons #Physics of Superconductivity and Magnetism #cond-mat.stat-mech #cond-mat.str-el #hep-th

paper · pdf · doi:10.1103/physrevlett.83.4914

published as Phys.Rev.Lett. 83 (1999) 4914-4917 · 4 pages, 1 figure, minor changes (typo in Eq. (3) corrected, references added), published version

openalex publication_date 1999/12/13 · arxiv created 1999/12/15 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

A continuous sequence of infinitesimal unitary transformations, combined with an operator product expansion for vertex operators, is used to diagonalize the quantum sine-Gordon model for \ensuremathβ²\ensuremath∈(2\ensuremathπ,\ensuremath∞). The leading order of this approximation already gives very accurate results for the single-particle gap in the strong-coupling phase. This approach can be understood as an extension of perturbative scaling theory since it links weak- to strong-coupling behavior in a systematic expansion. The method should also be useful for other strong-coupling problems that can be formulated in terms of vertex operators.

Citations

• Bosonization and Strongly Correlated Systems
• The renormalization group: Critical phenomena and the Kondo problem
• Flow‐equations for Hamiltonians

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