I String theory in 4 dimensions?

TheHeraclitus
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Does Non-critical string theory really allow only 4 dimensions? Why it's not more popular?
Non-critical string theory, on Wikipedia it says:
Although this allows the construction of a string theory in 4 spacetime dimensions, such a theory usually does not describe a Lorentz invariant background.
Has it been experimentally disproven or are other reasons for its apparent obscurity?
 
Physics news on Phys.org
Extra dimensions in string theory are a virtue rather than a nuisance. That's because theory in more dimensions is rich enough to accommodate a model as complex as 4-dimensional Standard Model, through various types of compactification or brane constructions. String theory in 4 dimensions, on the other hand, lacks such additional degrees of freedom so it lacks the needed richness. It could be a theory of something, but not a theory of everything.
 
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What are the strings in string theory made of? This question puts one back into square one. The reason Einstein's theory of relativity does not work in sub atomic level. Like many theories it involves Calculus. Calculus always assumes infinity as something real when it is not. That is the basis of these theories. We do not need strings to define matter. It could be simple presence vs non presence. Just like 1 and 0. When matter is compressed to the maximum (What thought to be infinity before but there is a limit to infinity which defines this maximum.) then you can achieve the zero. The same zero present in black holes and outside the universe or before big bang.
 
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Thread 'LQG Legend Writes Paper Claiming GR Explains Dark Matter Phenomena'
A new group of investigators are attempting something similar to Deur's work, which seeks to explain dark matter phenomena with general relativity corrections to Newtonian gravity is systems like galaxies. Deur's most similar publication to this one along these lines was: One thing that makes this new paper notable is that the corresponding author is Giorgio Immirzi, the person after whom the somewhat mysterious Immirzi parameter of Loop Quantum Gravity is named. I will be reviewing the...
I seem to notice a buildup of papers like this: Detecting single gravitons with quantum sensing. (OK, old one.) Toward graviton detection via photon-graviton quantum state conversion Is this akin to “we’re soon gonna put string theory to the test”, or are these legit? Mind, I’m not expecting anyone to read the papers and explain them to me, but if one of you educated people already have an opinion I’d like to hear it. If not please ignore me. EDIT: I strongly suspect it’s bunk but...
https://arxiv.org/pdf/2503.09804 From the abstract: ... Our derivation uses both EE and the Newtonian approximation of EE in Part I, to describe semi-classically in Part II the advection of DM, created at the level of the universe, into galaxies and clusters thereof. This advection happens proportional with their own classically generated gravitational field g, due to self-interaction of the gravitational field. It is based on the universal formula ρD =λgg′2 for the densityρ D of DM...

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