Speaker
Description
A review of the question how to put the Cartan Khronon into a gauge-gravity unified field theory is provided. The issues are several-fold, from conceptual to technical: suggestions for future developments are provided. The Cartan Khronon is quite special in its particular balance of self-dual Einstein-Cartan gravity constrained to waywiser form, thus producing ideal dust. However, supplying the Cartan radius vector constraint is generic, to the point of uncertain novelty — gauge-gravity models are plenty. Meanwhile, conceptual issues remain: what should the gauge-gravity unified phase even be like? How to model the Khronon — as a symmetry breaking object, field of time, or metric constituent? Which way to execute the symmetry breaking, and from what to where? It is argued the problem itself is in a subtle mixing of problems in different domains, alas with unsure guidance, observational and otherwise. One calculable way forward is to span all Lagrangian possibilities, and identify physical viability by sector. Another philosophical path is to heavily devise interpretation, to limit the permutations. Which to prefer?