Improved harmonic approximation and the 2D Ising model at T ¬=; Tc and h ¬=; 0
Abstract
We propose a new method to determine the unknown parameter associated with a self-consistent harmonic approximation. We check the validity of our technique in the context of the sine-Gordon model. As a non-trivial application we consider the scaling regime of the 2D Ising model away from the critical point and in the presence of a magnetic field h. We derive an expression that relates the approximate correlation length ξ, T - Tc and h.
- Publication:
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Journal of Physics A Mathematical General
- Pub Date:
- September 2002
- DOI:
- 10.1088/0305-4470/35/38/304
- arXiv:
- arXiv:hep-th/0209019
- Bibcode:
- 2002JPhA...35.8005I
- Keywords:
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- High Energy Physics - Theory;
- Condensed Matter
- E-Print:
- 11 pages, Latex, 3 figures. Accepted for publication in Journal of Physics A