Unified field theory of (the not mathematically well-defined) quantum electrodynamics. One can extend this system to include the weak and strong nuclear forces to get the Einstein–Yang–Mills–Dirac System. The French physicist Marie-Antoinette Tonnelat published a paper in the early 1940s on the standard commutation relations for the quantized spin-2 field. She continued this work in collaboration with Erwin Schrödinger after World War II. In the 1960s Mendel Sachs proposed a generally covariant field theory that did not require recourse to renormalisation or perturbation theory. In 1965, Tonnelat published a book on the state of research on unified field theories. In 1963 American physicist
A Brief History of Time to make a theory that combines the electromagnetic force, the weak nuclear force, and the strong nuclear force. This theory is called a "grand unified theory" (or a GUT). This theory tries to explain these forces in one big unified way or theory. Black holes are talked about in this chapter. Black holes are stars that have collapsed into one very small point. This small point is called a "singularity". Black holes suck things into their center because they have very strong gravity. Some of the things it can suck in are light and stars. Only very large stars, called