[ls-lah_33]

I'm surprised Sabine doesn't mention the way fermions are treated in Loop Quantum Gravity [1][2]. My understanding is they are treated as "non-local" or open loops of gravitational force, and thus entry and exit points in space-time. This makes them conceptually similar to the "wormhole model" of matter that Einstein and Rosen originally described.

[1] https://arxiv.org/pdf/gr-qc/9404010

[2] https://arxiv.org/pdf/1012.4719

[gradschoolfail]

My understanding is that this is the way fermions are treated in any modern theory of quantum gravity, and not specific to LQG?

[ls-lah_33]

Not sure what you mean, are you talking about ER = EPR? I think that's mostly a way of accounting for entanglement between particles, but it doesn't create the particles to begin with like in LQG. But my string theory knowledge is probably out of date, so I could be wrong.

[gradschoolfail]

You already related the “(open)loop quantization” in LQG to EPR=ER above, similar concept occurs in string theory too, almost unknown because its so foundational, see https://en.wikipedia.org/wiki/Born–Infeld_model, near the end, as well as some of the references there that discuss gravity.

“Creating” is a vague(r) term, do you mean “quantization”? Afaik the open-loop geometry of fermions is something any quantization scheme has to start with, the details are how one includes gravity, so without more details, one wouldnt be able to tell how LQG is different from string theory :)