Low-temperature expansion in the d = 4 Ising model

Charles James Elliot

Rodrigo Bissacot, Henrique Corsini

M F Sykes, David S. Gaunt

The derivation of low temperature (high field) expansions for the Ising model with spin S > 4 is described.

Lawrence E. Thomas, Yin Zhong

By conditioning on a subalgebra of observables, we develop low temperature expansions for certain quantum Ising models, which include transverse Ising models and anisotropic xy models. These expansions are majorized by the series for functions solving certain nonlinear partial differential equations. Convergence for the majorizing series follows from Cauchy–Kowalevski theory applied to the partial differential equations. The low temperature expansions imply long-range order.

H. Arisue, Kanehito Tabata

Syh-Fu Lee, Keh-Ying Lin