  Traditional quantum field theory can lead to enormous zero-point energy,
which markedly disagrees with experiment. Unfortunately, this situation is
built into conventional canonical quantization procedures. For identical
classical theories, an alternative quantization procedure, called affine field
quantization, leads to the desirable feature of having a vanishing zero-point
energy. This procedure has been applied to renormalizable and nonrenormalizable
covariant scalar fields, fermion fields, as well as general relativity. Simpler
models are offered as an introduction to affine field quantization.

High Energy Physics - Theory