The spin-foam approach to quantum gravity is part of the class of approaches, that also include loop quantum gravity and a variety of other methods, that sets out to quantize space-time rather than the gravitational force itself.
But, it turns out that "the continuum limit of spin foam dynamics does lead to massless gravitons."
The result is not at all obvious, and the analysis in the linked paper is challenging to follow. But it is also a result that is expected because both spin-foam approaches and graviton based quantum gravity approaches are trying to approximate general relativity. And, general relativity is widely believed to be the classical limit of a quantum theory with a massless spin-2 graviton.
It could be that at some deep level quantizing space-time, and quantizing gravity in a more or less canonical way with a massless spin-2 graviton, are equivalent, with one implying the other and visa versa.
2 comments:
i'm curious as to whether this is compatible with twistor theory and specifically,
gravi-weak unification in twistor space
I don't know.
Post a Comment