A Gauss sum over a finite field combines a multiplicative character
with a nontrivial additive character
in the sum
where is extended by zero at zero. For a
nontrivial
,
its absolute value is
. The normalized sum
therefore lies on the unit
circle. A character of order 3 gives a cubic Gauss
sum. Quadratic exponential sums are treated as Gaussian sums. The additive-character
normalization matters when comparing first moments.