# String theory in 4 dimensions?

• I
• TheHeraclitus
In summary, string theory in 4 dimensions lacks the needed richness to fully describe a Lorentz invariant background, making it less popular than theories with extra dimensions. However, it still has potential to explain certain phenomena. The strings in string theory are not made of anything, as they are simply mathematical objects used to describe matter. The use of calculus and the assumption of infinity are key components in these theories.
TheHeraclitus
TL;DR Summary
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?

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.

TheHeraclitus and PeroK
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.

Motore and weirdoguy

• Beyond the Standard Models
Replies
31
Views
2K
• Beyond the Standard Models
Replies
1
Views
1K
• Beyond the Standard Models
Replies
4
Views
2K
• Beyond the Standard Models
Replies
47
Views
4K
• Beyond the Standard Models
Replies
2
Views
2K
• Beyond the Standard Models
Replies
1
Views
1K
• Beyond the Standard Models
Replies
0
Views
1K
• Beyond the Standard Models
Replies
1
Views
2K
• Beyond the Standard Models
Replies
4
Views
1K
• Beyond the Standard Models
Replies
3
Views
2K