In a recent preprint Renate Loll et al. present numerical evidence that causal dynamical triangulation is eventually a discretization of Horava-Lifshitz gravity.

But is this really good news?

In an earlier paper by Christos Charmousis et al. an argument was given that "the original Horava model, and its 'phenomenologically viable' extensions do not have a perturbative General Relativity limit at any scale". Lubos wrote more about that at the time and there is also this paper with a more general argument.

I am neither an expert on CDT nor Horava-Lifshitz gravity and would welcome comments about this. (Of course, I always welcome comments!)


Anonymous said...

Maybe I misunderstand something, but they have no good indication of a second order transition so far.
Therefore we don't know if their model has a reasonable continuum limit at all.
So what are we talking about here?

wolfgang said...

All this is very preliminary I assume and the order of the phase transitions has not really been determined yet.

They seem to think that the B-C transition could be 2nd order or perhaps (weak) 1st order.
If it is 1st order there is still hope that the end point is 2nd order.

But my point is that the results of Charmousis etc. suggest that this is not the case (because one cannot reach Einstein gravity from Horava-Lifshitz gravity by continuously changing the 'anisotropy parameter' as Ambjorn et al. hope).