Does loop quantum gravity hint at the Standard model?

[Spinnor]

Have loop quantum theorists looked forward to how one might fit the standard model into loop quantum gravity?

Thank you for any help.

 

[marcus]

I would say on the whole LQG does not hint at the Std Mdl.
And that the main part of the Loop research community has not been exploring ways to include particle physics. They have a big enough challenge just to

1. formulate a background independent quantum field theory of spacetime geometry
2. formulate a path integral dynamics (using spin foam)
3. show it yields Gen Rel in the limit
4. derive testable consequences about the early universe that can be checked by observation.But there has been some marginal work exploring "hints" of the Std Mdl.
As a handle on this, look up the papers of Jonathan Hackett:
http://arxiv.org/find/grp_physics/1/au:+Hackett_J/0/1/0/all/0/1

The Hackett page will give you links to pages of his collaborators. If you look at all the people he has collaborated with, and look at their papers, you will pretty much have the lot.

Especially notable is Yidun Wan (who has, I think, done the most work on this of anybody.)
http://arxiv.org/find/grp_physics/1/au:+Wan_Y/0/1/0/all/0/1
and likewise Sundance Bilson-Thompson (who first pointed out how particles correspond to braids in a network).
http://arxiv.org/find/grp_physics/1/au:+Bilson_Thompson_S/0/1/0/all/0/1
but you will also see co-authors Lee Smolin, Fotini Markopoulou, and Louis Kauffman

Hackett is not necessarily a ringleader in this area, but he has collaborated widely so he provides a handle on the rest.

The person with the most energy and determination in this research is Yidun Wan, and he has been among the most creative. What this means if that if a year goes by and Yidun Wan does not publish new results then it is possible that the field is "stuck" and not going anywhere. So look at the dates on Yidun Wan's papers. And the other people's too.
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If you want to know what is currently going on in Loop/Foam QG, then you have to realize there was a major renovation in 2007, essentially redefining the field and basing it on the EPRL spin foam model. (Engle, Pereira, Rovelli, Livine).

The most significant thing that happened this year was the paper of Jerzy Lewandowski et al that extended the EPRL foam and made it better. Now the spin foam model is completely compatible with the old LQG kinematics of spin networks. Now we can really say that the 4D foam contains the 3D nets and shows their evolution.
Here is the Lewandowski paper, which I think is defining for this year:
http://arxiv.org/abs/0909.0939

Also (for what it's worth) the new Lewandowski version of spin foam allows for braids--knots of various kinds in the spin networks--or at least leans in that direction. But probably we shouldn't bother thinking about braids unless Yidun Wan and the others start writing papers again.

 

[Entropia]

Loop quantum gravity (LQG) and the Standard Model (SM) are two different theories that attempt to explain fundamental aspects of our universe. LQG is a theoretical framework that aims to reconcile Einstein's theory of general relativity with quantum mechanics, while the SM is a well-established theory that describes the fundamental particles and forces of the universe.

There is ongoing research and discussion about the potential connections between LQG and the SM. However, it is important to note that LQG is still a developing theory and there is no consensus on how it may fit with the SM.

Some LQG theorists have proposed ways in which the SM could potentially be incorporated into LQG. For example, some have suggested that the SM particles could be described as excitations in the quantum geometry of space predicted by LQG. Others have explored the possibility of incorporating the SM gauge symmetries into LQG.

However, there is no definitive answer on how the SM could be incorporated into LQG, and it remains an area of active research and debate. Additionally, there are still many challenges and open questions within both LQG and the SM, making it difficult to fully integrate the two theories at this point in time.

In conclusion, while there have been attempts to connect LQG and the SM, there is currently no clear indication that LQG hints at the SM. More research and understanding is needed in both theories before any definitive conclusions can be drawn about their relationship.