Borel-Pade re-summation of the $beta$-functions describing Anderson localisation in the Wigner-Dyson symmetry classes

We describe a Borel-Pade re-summation of the $beta$-function in the three Wigner-Dyson symmetry classes. Using this approximate $beta$-function we discuss the dimensional dependence of the critical exponent and compare with numerical estimates. We also estimate the lower critical dimension of the symplectic symmetry class.