Fluctuating local field method for the disordered Ising model

Abstract

We present a method for computing thermal properties of classical spin clusters with arbitrarily chosen interactions between spins. For such systems, instability channels are \textit{a priori} not known. The method is based on the Fluctuating Local Field (FLF) approach, the effective description of the system with a nonlinear and fluctuating field, and achieves substantial improvements over mean-field theory. We show that two fluctuating modes are sufficient for numerically accurate solution of systems consisting of two dozen spins, while for larger systems it is needed to account for a larger number of fluctuating modes for a full quantitative agreement with the exact solution.

References in corpus (6)

• Spin-lattice coupling in frustrated antiferromagnets
• Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory
• High-frequency asymptotics of the vertex function: diagrammatic parametrization and algorithmic implementation
• Multiloop functional renormalization group that sums up all parquet diagrams
• Dual parquet scheme for the two-dimensional Hubbard model: modelling low-energy physics of high-$T_c$ cuprates with high momentum resolution
• Fluctuating local field method probed for a description of small classical correlated lattices