Predicting new particles and explaining the properties of those already known
The basis of knowledge about the construction of the universe is the notion of elementary particles and their impact on surroundings. When a particle approaches close to another one, both are experiencing forces, hence the concept of the force field appears. Classical field theory was created by Maxwell to describe the interaction of electric charges before the discovery of elementary charge carriers — electrons. Experimental study of the properties of electrons and other elementary particles revealed the incapability of the classical field theory to describe their interactions at short distances and at high energies. This was the reason for developing the quantum theory of the electromagnetic field, which was then generalized to describe other fundamental interactions and successfully predicted the discovery of new particles and non-trivial phenomena.