I was wondering if anyone has ever tried to formulate a string theory with a 3D string rather than a 1D string. Has this been done? Is this much more complicated?
I guess you've never noticed all this talk of branes or membranes.
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PhilosophyofPhysics
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Well...
Branes are not what I'm thinking about unless a 3D string is equivalent to a 3 brane. I've read the first half of Zwiebach, but I might have forgot about the part where he said a 1 D brane was a string.
Anyway, I'm thinking kind of a real string with width, height and length but just exceedingly small.
What you are talking about is a small 3-brane. One can formulate such a theory, but unlike the string theory (1-brane), the quantum theory contains UV divergences that cannot be eliminated, at least not perturbatively. In fact, UV divergences can be (perturbatively) eliminated only for objects extended in 1 dimension (not 0, not 2, ...), which is related to the fact that the conformal group in 2 dimensions (the other dimension is due to the extension in time) is much reacher than in other numbers of dimensions.
This is an alert about a claim regarding the standard model, that got a burst of attention in the past two weeks.
The original paper came out last year:
"The electroweak η_W meson" by Gia Dvali, Archil Kobakhidze, Otari Sakhelashvili (2024)
The recent follow-up and other responses are
"η_W-meson from topological properties of the electroweak vacuum" by Dvali et al
"Hiding in Plain Sight, the electroweak η_W" by Giacomo Cacciapaglia, Francesco Sannino, Jessica Turner
"Astrophysical...
this thread is to open up discussion on Gravi-GUT as theories of everything
GUT or Grand Unified Theories attempt to unify the 3 forces of weak E&M and strong force, and Gravi-GUT want to add gravity.
this peer reviewed paper in a journal on Gravi-GUT
Chirality in unified theories of gravity
F. Nesti1 and R. Percacci2
Phys. Rev. D 81, 025010 – Published 14 January, 2010
published by
Physical Review D
this paper is cited by another more recent Gravi-GUT
these papers and research...
In LQG and LQC there are solutions called "black to white transition". I'll add some references:
(Rovelli)https://arxiv.org/abs/1905.07251
(Rovelli)https://arxiv.org/abs/2302.03872
(Rovelli)https://arxiv.org/abs/1803.06330
(Rovelli)https://arxiv.org/pdf/1802.04264
(Rovelli)https://arxiv.org/abs/2108.12823
https://arxiv.org/abs/2304.02691
https://arxiv.org/abs/2110.07589
https://arxiv.org/abs/2009.01788
https://arxiv.org/abs/1911.12646
https://arxiv.org/abs/1801.03027...