We present asymptotically exact results for the real time order parameter
correlations of a class of d=1 Ising models in a transverse field at low
temperatures (T) on both sides of the quantum critical point. The correlations
are a product of a T-independent factor determined by quantum effects, and a
T-dependent relaxation function which comes from a classical theory. We confirm
our predictions by a no-free-parameter comparison with numerical studies on the
nearest neighbor spin-1/2 model.Comment: Final version to be published in Physical Review Letters. The
postscript file is also available by anonymous ftp at
ftp://chopin.ucsc.edu/pub/dynamics.ps.g