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 psychology
The emergence of quantum field theories, known as Quantum Physics and Quantum Mechanics, not only revolutionised the classical Newtonian physics, but have become its fundamental theory. The applications of the quantum theory are being widely utilised in modern sciences, technologies, research, medicine and economy. Quantum theory seeks to explain behaviour of matter and energy at its smallest subatomic scales. It posits that at its fundamental subatomic level matter particles exist solely as waves of probabilities and acquire material properties only after the act of observation by an independent observer. Quantum physics terminology describes this phenomenon as the "observer effect" or "collapse of the wave function". In the fields of cognitive and behavioural psychology the quantum paradigm offers a complementary theoretical framework in which the individual observer and his/her phenomenological experiences represent a highly sophisticated and mutually interactive feedback system. In the field of neuroscience it provides an alternative experimental model in which neuronal brain mechanisms can be studied and analysed.