# Exploring Kaluza-Klein Theory in the 5th Dimension Reality

• Marceli
In summary, the conversation discussed Kaluza-Klein theory and its application to quantum mechanics. The theory involves extra dimensions and the cylinder assumption, which is the basis for electromagnetism. However, the theory has lost its appeal and is considered backwater. The conversation also touched on the representation of quantum non-locality in KK theory and the concept of cluster decomposition in quantum field theory.
Marceli
I am still learning of Kaluza-Klein theory. Is KK theory applying to quantum mechanics? How quantum non-locality can be represented by KK theory?

Wikipedia has an introductory article on Kaluza Klein theory that may be of interest:

http://en.m.wikipedia.org/wiki/Kaluza–Klein_theory

One thing to be aware of is that this is a very deep theory and there may not be anyone here who can properly or adequately comment on it let alone answer your questions.

What is your interest in KK theory and what level of schooling do you have so far?

Simply brilliant!

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Must be some mathematical representation of entanglement reality in extra dimensions, but from non-local phenomena seems Universe was created from one common extra dimensional point so it stays forever for any point in our Universe! My mathematical knowledge from University is not so strong to develop Kalusa-Klein formulas currently therefore I am using mine deductive reasoning imagination.

I'm starting with the assumption that the 5th dimension is infinite universes like MWI.

jerromyjon said:
I'm starting with the assumption that the 5th dimension is infinite universes like MWI.

Actually in KK its curled up in a circle and this enforces the so called cylinder assumption which is the real basis of why KK works:
http://en.wikipedia.org/wiki/Kaluza–Klein_theory

The cylinder assumption is the geometry of a circle ie U(1) symmetry which is in fact the basis EM - so in a sense its EM in EM out. Once this was understood it lost much of its appeal and is pretty backwater these days.

Regarding locality it's quantisation would be a QFT and locality in that depends on the so called Cluster Decomposition property:
http://en.wikipedia.org/wiki/Cluster_decomposition_theorem

Thanks
Bill

Thanks Bhoppa, it seems now we can close the thread.

## 1. What is Kaluza-Klein theory?

Kaluza-Klein theory is a theoretical framework in physics that attempts to unify the forces of gravity and electromagnetism by adding an extra dimension to our understanding of space-time. It proposes that our universe has a fifth dimension in addition to the four dimensions of space and time that we are familiar with.

## 2. How does the fifth dimension affect our reality?

The fifth dimension, according to Kaluza-Klein theory, is a compactified dimension that is too small for us to perceive directly. However, its effects can be observed in the behavior of subatomic particles, gravity, and the curvature of space-time. It is believed that the fifth dimension plays a crucial role in unifying the forces of nature and could potentially lead to a more complete understanding of the universe.

## 3. What evidence supports Kaluza-Klein theory?

There is currently no direct evidence for the existence of a fifth dimension. However, Kaluza-Klein theory has been successful in predicting certain phenomena, such as the quantization of electric charge and the existence of magnetic monopoles. Additionally, the theory is consistent with other well-established theories, such as Einstein's theory of general relativity.

## 4. How does Kaluza-Klein theory relate to string theory?

Kaluza-Klein theory is often seen as a precursor to string theory, as both theories propose the existence of extra dimensions beyond the four we are familiar with. However, string theory takes this concept further by proposing that the fundamental building blocks of the universe are not particles, but tiny vibrating strings that exist in 10 or 11 dimensions.

## 5. Could the fifth dimension be the key to a unified theory of everything?

It is currently unknown if the fifth dimension or any other extra dimensions are the key to a unified theory of everything. While Kaluza-Klein theory and string theory offer promising possibilities, further research and experimentation are needed to fully understand the role of extra dimensions in our universe.

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