Related Theories
CDT has some similarities with loop quantum gravity, especially with its spin foam formulations. For example, the Lorentzian Barrett-Crane model is essentially a non-perturbative prescription for computing path integrals, just like CDT. There are important differences, however. Spin foam formulations of quantum gravity use different degrees of freedom and different Lagrangians. For example, in CDT, the distance, or "the interval", between any two points in a given triangulation can be calculated exactly (triangulations are eigenstates of the distance operator). This is not true for spin foams or loop quantum gravity in general.
Another approach to quantum gravity that is closely related to causal dynamic triangulation is called causal sets. Both CDT and causal sets attempt to model the spacetime with a discrete causal structure. The main difference between the two is that the causal set approach is very general, whereas CDT assumes a specific relationship between the lattice of spacetime events and geometry. Consequently, the Lagrangian of CDT is constrained by the initial assumptions to the extent that it can be written down explicitly and analyzed (see, for example, hep-th/0505154, page 5), whereas causal-set theory is not as completely developed at this point.
Read more about this topic: Causal Dynamical Triangulation
Famous quotes containing the words related and/or theories:
“So universal and widely related is any transcendent moral greatness, and so nearly identical with greatness everywhere and in every age,—as a pyramid contracts the nearer you approach its apex,—that, when I look over my commonplace-book of poetry, I find that the best of it is oftenest applicable, in part or wholly, to the case of Captain Brown.”
—Henry David Thoreau (1817–1862)
“It takes twenty or so years before a mother can know with any certainty how effective her theories have been—and even then there are surprises. The daily newspapers raise the most frightening questions of all for a mother of sons: Could my once sweet babes ever become violent men? Are my sons really who I think they are?”
—Mary Kay Blakely (20th century)