

Quantization 

In physics, quantization is a procedure for constructing a quantum field theory starting from a classical field theory. This is a generalization of the procedure for building quantum mechanics from classical mechanics. 

Field quantization can also be considered, as in the quantization of the electromagnetic field, where one refers to photons as field quanta (for instance as light quanta). 

This procedure is basic to theories of particle physics, nuclear physics, condensed matter physics, and quantum optics.


Quantization converts classical fields into operators acting on quantum states of the field theory. The lowest energy state is called the vacuum state and may be very complicated. 

The reason for quantizing a theory is to deduce properties of materials, objects or particles through the computation of quantum amplitudes. Such computations have to deal with certain subtleties called renormalization, which, if neglected, can often lead to nonsense results, such as the appearance of infinities in various amplitudes.


The first method to be developed for quantization of field theories was canonical quantization. 

Canonical quantization of a field theory is analogous to the construction of quantum mechanics from classical mechanics.

