Universal Amplitude Ratios in the Ising Model in Three Dimensions

Abstract

We use a high-precision Monte Carlo simulation to determine the universal specific-heat amplitude ratio A+/A- in the three-dimensional Ising model via the impact angle ϕof complex temperature zeros. We also measure the correlation-length critical exponent νfrom finite-size scaling, and the specific-heat exponent αthrough hyperscaling. Extrapolations to the thermodynamic limit yield ϕ= 59.2(1.0) degrees, A+/A- = 0.56(3), ν= 0.63048(32) and α= 0.1086(10). These results are compatible with some previous estimates from a variety of sources and rule out recently conjectured exact values.

17 pages, 5 figures