Nonperturbative renormalization group approach to the Ising model: a\n derivative expansion at order $\\partial^4$

Abstract

On the example of the three-dimensional Ising model, we show that\nnonperturbative renormalization group equations allow one to obtain very\naccurate critical exponents. Implementing the order $\\partial^4$ of the\nderivative expansion leads to $\\nu=0.632$ and to an anomalous dimension\n$\\eta=0.033$ which is significantly improved compared with lower orders\ncalculations.\n