Potential said:
Questions: Where can I obtain the most advanced published papers regarding valid unification theories? ...
It depends on how you see the problem of unification. From one perspective the central unification problem is to reconcile quantum theory with our theory of geometry (how geometry is affected by matter and why we ordinarily experience it as almost but not quite the same as the flat geometry of Pythagoras and Euclid.)
In other words, the central unification problem is a quantum theory of
what space and time are and how they interact with matter.
At the present, our dominant theory of what space and time are, and how geometry interacts with matter, is 1915 classic General Relativity.
Quantum field theory (QFT) our basic theory of matter has not been put on a GR basis. One way of stating the unification goal I'm talking about is to reach a general relativistic quantum field theory. To construct a new model of spacetime, and to rebuild QFT on that new geometric foundation.
There are several quite different ways of seeing the main unification goal and it would be arrogant and not very bright to pretend that only one is the correct one, or that only one version of the goal subsumes all the others. In any case you can pick up on a variety of different currents just by keeping alert. I will describe one.
You ask about an up-to-date paper. Here is something rather surprising. I think that from one perspective one of the most advanced papers is written for general audience and was published in the Scientific American last year!
http://www.signallake.com/innovation/SelfOrganizingQuantumJul08.pdf
It is called
The Self-Organizing Quantum Universe. It's extensively illustrated with graphics that help get the ideas across. Published July 2008. Shows what a new picture of spacetime might turn out to look like. Interesting fractal quality down at Planck length scale. Space no longer 3D at very small scale---dimensionality becomes fractional and declines down to numbers like 2.1 and 1.9, reminiscent of fractals.
Several other approaches to quantum geometry/gravity have also shown signs of this fractal or chaotic behavior of geometry at very small scale. One thinks of seething wormholes, foam, froth, something. Not the regular continuum. Perhaps a Heisenberg uncertain concept of continuum. Anyway a new model of the continuum is emerging from several of these QG approaches. The special thing about this SciAm article is that it reports on a mathematical model of quantum continuum which looks right at large scale.
At large scale it gives a classic solution to General Relativity, one with dark energy, and realistic accelerating expansion as we seem to be detecting today. The socalled De Sitter universe. This is good news, so I guess that is why that team made the Scientific American with their result.
If you want more technical articles, they have links at the end of the SciAm article, and also you can ask. They are easy to get.
