Einstein–Maxwell–Dirac equations (EMD) are related to quantum field theory. The current Big Bang Model is a quantum field theory in a curved spacetime. Unfortunately, no such theory is mathematically well-defined; in spite of this, theoreticians claim to extract information from this hypothetical theory. On the other hand, the super-classical limit of the not mathematically well-defined QED in a curved spacetime is the mathematically well-defined Einstein–Maxwell–Dirac system. (One could get a similar system for the standard model.) As a super theory, EMD violates the positivity condition in the Penrose–Hawking singularity theorems. Thus, it is possible that there would be complete solutions without any singularities – Yau has in fact constructed some. Furthermore, it is known that the Einstein–Maxwell–Dirac system admits of solitonic solutions, i.e., classical electrons and photons. This is the kind of theory Einstein was hoping for. In fact, in 1929 Weyl wrote Einstein that any unified theory would need to include the metric tensor, a gauge field, and a matter field. Einstein considered the Einstein–Maxwell–Dirac system by 1930. He probably didn't develop it because he was unable to geometricize it. It can now be geometricized as a non-commutative geometry; here, the charge e and the mass m of the electron are geometric invariants of the non-commutative geometry analogous to pi.
The Einstein–Yang–Mills–Dirac Equations provide an alternative approach to a Cyclic Universe which Penrose has recently been advocating. They also imply that the massive compact objects now classified as Black Holes are actually Quark Stars, possibly with event horizons, but without singularities.
One way of trying to construct a rigorous QED and beyond is to attempt to apply the deformation quantization program to MD, and more generally, EMD. This would involve the following.
Program for SCESM
The Super-Classical Einstein-Standard Model:
- Extend Asymptotic Completeness, Global Existence and the Infrared Problem for the Maxwell–Dirac Equations to SCESM (Memoirs of the American Mathematical Society), by M. Flato, Jacques C. H. Simon, Erik Taflin.
- Show that the positivity condition in the Penrose–Hawking singularity theorem is violated for the SCESM. Construct smooth solutions to SCESM having Dark Stars. See here: The Large Scale Structure of Space-Time by Stephen W. Hawking, G. F. R. Ellis
- Follow three substeps:
- Derive approximate history of the universe from SCESM – both analytically and via computer simulation.
- Compare with ESM (the QSM in a curved space-time).
- Compare with observation. See: Cosmology by Steven Weinberg
- Show that the solution space to SCESM, F, is a reasonable infinite dimensional super-sympletic manifold. See: Supersymmetry for Mathematicians: An Introduction
- The space of fields F needs to be quotiented by a big group. One hopefully gets a reasonable sympletic noncommutative geometry, which we now need to deformation quantize to obtain a mathematically rigorous definition of SQESM (quantum version of SCESM). See: Deformation Theory and Symplectic Geometry by Daniel Sternheimer, John Rawnsley
- Derive history of the universe from SQESM and compare with observation.
- Varadarajan, V. S. (2004). Supersymmetry for Mathematicians: An Introduction. Courant Lecture Notes in Mathematics 11. American Mathematical Society. ISBN 0-8218-3574-2.
- Deligne, Pierre (1999). Quantum Fields and Strings: A Course for Mathematicians 1. American Mathematical Society. ISBN 0-8218-2012-5.
- Deligne, Pierre (1999). Quantum Fields and Strings: A Course for Mathematicians 2. American Mathematical Society. ISBN 0-8218-2012-5.
- van Dongen, Jeroen (2010). Einstein's Unification. Cambridge University Press. ISBN 0521883466.