Does a GUT have to have gravity involved?

[robertroman10]

To make a grand unified theory "complete", does it have to involve gravity? If gravity is more of a warp of space-time, and less of an actual force, then do we already have a grand unified theory (since we have combined the other 3 forces), or do we NEED gravity to be a force to have a GUT.

 

[mathman]

The main unresolved problem in this area is that quantum theory and general relativity lead to nonsensical results when both have to applied at the same time (inside a black hole for example). This is the motivation for the search for a theory which includes both.

 

[robertroman10]

The main unresolved problem in this area is that quantum theory and general relativity lead to nonsensical results when both have to applied at the same time (inside a black hole for example). This is the motivation for the search for a theory which includes both.

Ohh I see. So would gravity have to be a force to produce non gibberish results?

 

[Fra]

Usually with GUT one means unification of EM, weak and strong interactions. However there exist not even a commonly accepted official GUT. Normally unification measn explainning all three interactions by some common mechanism, rather than just three separately parameterised theories "patched together".

TOE is the term that's used for a GUT + gravity.

If it's consistent to separate the GUT from the TOE without open wires, may be of debate, as suggested by the different research programs.

I don't think the geometrisation of physics has anything at all to do with this problem; how is an "actual force" distinguished from geometric effects anyway? ;)

Geometric methods in physics have been extremely popular that's clear. But I think it's more like a reformulation that IMO has a lot of realist flavour to it. It does not add exaplanatory or predictive power per see. I think it probably adds possible useful ideas (by exploiting tools and results know from geometry). And clearly, this has have good success, not only only in GR but also in SM.

But this may or or many not also be responsible for a lot of people getting stuck thinking in terms of geometry and manifolds. Now, perhaps the next step is not best cast in geometry. Personally I think the geometrisation of physics has been both a gift and a poison.

/Fredrik

 

[PieOperator]

To make a grand unified theory "complete", does it have to involve gravity? If gravity is more of a warp of space-time, and less of an actual force, then do we already have a grand unified theory (since we have combined the other 3 forces), or do we NEED gravity to be a force to have a GUT.

If you really desire to fully understand GUT, then you have to learn about the computer chip after you study matrices. Engineer a microchip and program this chip to graph in 3 dimensions, and you can all start to understand how to think in more than 3 dimensions!