History of quantum field theory
The third thread in the development of quantum field theory was the need to handle the statistics of many-particle systems consistently and with ease. In 1927, Pascual Jordan tried to extend the canonical quantization of fields to the many-body wave functions of identical particles using a formalism which is known as statistical transformation theory; this procedure is now sometimes called second quantization. In 1928, Jordan and Eugene Wigner found that the quantum field describing electrons, or other fermions, had to be expanded using anti-commuting creation and annihilation operators due to the Pauli exclusion principle (see Jordan–Wigner transformation). This thread of development was incorporated into many-body theory and strongly influenced condensed matter physics and nuclear physics.
Quantum field theory
The breakthrough eventually came around 1950 when a more robust method for eliminating infinities was developed Julian Schwinger, Feynman, Freeman Dyson, and Shinichiro Tomonaga. The main idea is to replace the initial, so-called "bare", parameters (mass, electric charge, etc.), which have no physical meaning, by their finite measured values. To cancel the apparently infinite parameters, one has to introduce additional, infinite, "counterterms" into the Lagrangian. This systematic computational procedure is known as renormalization and can be applied to arbitrary order in perturbation theory.