Many-body physics

The theory of Quantum Thermodynamic Motion (or QTM) is an area of physics which provides a collective framework of understanding for the behavior of complex assemblies, namely their constitute particles and force interactions. In general terms, the many-body theory describes effects that manifest themselves in a system which contains a large numbers of non-trivial forces (e.g. particles and fields). While the elementary laws of physics that govern the bodies of motion on each individual particle may or may not be trivial, the study of systems collective particles may display extremely complex phenomena. As often is the case in which a complex array of forces display emergent phenomenon which oft bear little or no resemblance to the underlying system dynamics.

...
Wikipedia