UNIVERSAL AMPLITUDE RATIOS IN THE 3-DIMENSIONAL ISING-MODEL

We present a high precision Monte Carlo study of various universal amp litude ratios of the three-dimensional Ising spin model. Using state o f the art simulation techniques we study the model close to criticalit y in both phases. Great care is taken to control systematic errors due to finite size effects and correction to scaling tel ms. We obtain C/C- = 4.75(3), f(+.2nd)/f(-.2nd) = 1.95(2) and u = 14.3(1). Our resul ts are compatible with those obtained by field theoretic methods appli ed to the phi(4) theory and high- and low-temperature series expansion s of the Ising model. Tile mismatch with a previous Monte Carlo study by Ruge et nl remains to be understood.