We calculate the effective action for quantum electrodynamics (QED) in D =
2,3 dimensions at the quadratic approximation in the gauge fields. We analy
ze the analytic structure of the corresponding nonlocal boson propagators n
onperturbatively in k/m. In two dimensions for any nonzero fermion mass, we
end up with one massless pole for the gauge boson. We also calculate in D
= 2 the effective potential between two static charges separated by a dista
nce L and find it to be a linearly increasing function of L in agreement wi
th the bosonized theory (massive sine-Gordon model). In three dimensions we
find nonperturbatively in k/m one massive pole in the effective bosonic ac
tion leading to screening. Fitting the numerical results we derive a simple
expression for the functional dependence of the boson mass upon the dimens
ionless parameter e(2)/m.