Year: 2006
Type: article
Abstract: A systematic approach to the calculations of the non-perturbative contributions to the free energy in the ferromagnetic phase of the random field Ising model is developed. It is demonstrated that such contributions appear due to instanton-like excitations localized in space, which exist only in dimensions D ≤3. It is shown that away from the critical region such instanton solutions are described by the set of the mean-field saddle-point equations for the replica vector order parameter, and these equations can be formally reduced to the only saddle-point equation of the pure system in dimensions ( D −2). In the marginal case, D = 3, the corresponding non-analytic contribution is computed explicitly. The nature of the phase transition in the three-dimensional random field Ising model is discussed.
Author: Vik S Dotsenko
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2000304263