<t>By some old results of Schoenberg, for any times [$]t_1,t_2,\dots,t_n[$], the matrix with element [$]i,j[$] given by [$]\exp(-|t_i-t_j|^2)[$] is positive definite. If I am not mistaken, this is sufficient for the existence of a Gaussian stochastic process with auto-covariance function [$]\exp(-s^...