Causal Dynamical Triangulation (CDT)

I read in Scientific American magazine that a new theory called causal dynamical triangulation (CDT) has emerged as a promising approach to solving the problem of unifying the laws of gravity with those of quantum mechanics. For 20 years the leading contender in this quest has been string theory. String theory sets minuscule strings of energy against a fixed background of spacetime. String theory does not generate the spacetime, only the particles and forces that inhabit it.
In the 1980's and 1990's loop quantum gravity was developed as another attempt to unify the laws of physics. Loop quantum gravity describes space as a network of tiny volumes. It does generate spacetime. It has achieved some successes, but has yet to show that the tiny volumes of the theory always come together to form the 4-dimensional spacetime of our everyday world. CDT, which constructs spacetime geometries from 4-simplexes (the equivalent of a tetrahedron, but in four dimensions) is less than 10 years old, but has already achieved this.
The next step for CDT is to incorporate matter into the model to see if it can simulate the full equations of general relativity. Lee Smolin, one of the pioneers of loop quantum gravity, has said that CDT may eventually yield testable predictions, such as slight changes in the speed of high-energy photons caused by the models' nonclassical geometry at small scales.