Within the framework of white noise analysis on the probability space
Omega = L(R(d), R(M)), the recent work by Johnson and Kallianpur on t
he Hu-Meyer formula, traces, and natural extensions is generalized to
the multiparameter case: d>1. Besides providing a more general setting
for these topics, the paper gives an alternative definition for the t
races, a distributional version of the natural extension, and a genera
lized Kallianpur-Feynman distribution. The development illustrates how
traces and natural extensions are intimately related to Wick products
and the change of covariance formula from quantum field theory, as we
ll as to the projective tenser product of Hilbert spaces from function
al analysis.