What is k-Minkowski spacetime, and is it a tool in a theory of quantum gravity?

In summary: I just thought that the metric tensor was a 4D vector. For your second question, I am not sure what you're asking.
  • #1
nomadreid
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What is k-Minkowski spacetime, and...

In http://www.physorg.com/news157203574.html, k-Minkowski spacetime, which decreases down towards zero at small scales, is mentioned as a possible tool in a theory of quantum gravity and spacetime. But it is very, very vague. First, how is k-Minkowski space-time defined, and where precisely would it enter? Is the "k" here the same as the "q" in the description of the quantum group given in http://en.wikipedia.org/wiki/Quantum_group#Drinfel.27d-Jimbo_type_quantum_groups? Roughly what role would such fractional spacetime play? An explanation for a non-physicist (but with a mathematical background) would be greatly appreciated.
 
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K-Minkowski spacetime is a generalization of Minkowski spacetime in which the signature of the metric tensor is changed from the standard signature of Minkowski spacetime to the signature of the Lorentzian metric. It is often sufficient to use this model for background geometry when working with curved spacetimes.
 
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  • #3
Thanks, Greg Bernhardt!
 
  • #4
Greg Bernhardt said:
the signature of the metric tensor is changed from the standard signature of Minkowski spacetime to the signature of the Lorentzian metric.
What's the difference between Minkowski and Lorentzian signature?

A bonus question, is k-Minkowski the same as kappa-Minkowski?
 
  • #5
Greg Bernhardt said:
the standard signature of Minkowski spacetime to the signature of the Lorentzian metric.
From https://mathworld.wolfram.com/MetricSignature.html
"For n-dimensional Lorentzian space Rn-1,n , the metric signature is (n-1,n) , e.g., (3,1) (as above) for the Minkowski space of special relativity."
So if I understand correctly (wishing to be corrected), perhaps by "changing" the signature one means that in generalizing the Minkowski to more dimensions than 4, one generalizes the signature as well to the Lorentzian.

Demystifier said:
A bonus question, is k-Minkowski the same as kappa-Minkowski?
I am presuming that the author of the article (first link in my original post) used k instead of κ (kappa) out of typographical reasons. (Which may or may not be a euphemism...:rolleyes:)
 
  • #6
Demystifier said:
What's the difference between Minkowski and Lorentzian signature?

A bonus question, is k-Minkowski the same as kappa-Minkowski?
For your first question, I am not sure there's even such a thing as a Lorentzian metric.
There's a Lorentz transformation and Minkowski metric or space-time.
Before I learned GR from Schutz's book I didn't think to myself that the global spacetime metric may be flat, i.e. Minkowski.
 
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1. What is k-Minkowski spacetime?

K-Minkowski spacetime is a mathematical concept that extends the traditional Minkowski spacetime, which is used in special relativity, to include a parameter k that represents a noncommutative structure. This noncommutative structure is useful in the study of quantum gravity, as it allows for a more flexible and consistent framework for combining quantum mechanics and general relativity.

2. How does k-Minkowski spacetime differ from traditional Minkowski spacetime?

K-Minkowski spacetime differs from traditional Minkowski spacetime in that it introduces a noncommutative structure, meaning that the order in which operations are performed is important. This noncommutative structure is necessary for incorporating quantum mechanics into the framework of general relativity.

3. Is k-Minkowski spacetime a proven concept?

While k-Minkowski spacetime is a well-studied mathematical concept, it is not yet a proven concept in the sense that it has not been experimentally confirmed. However, it has shown promise in theoretical models and has been used in various calculations in the field of quantum gravity.

4. How is k-Minkowski spacetime used in a theory of quantum gravity?

K-Minkowski spacetime is used as a mathematical tool in the study of quantum gravity. It allows for a more consistent framework for combining quantum mechanics and general relativity, which are two of the most fundamental theories in physics. By incorporating a noncommutative structure, k-Minkowski spacetime helps to address the challenges and inconsistencies that arise when trying to unite these two theories.

5. Does the inclusion of k-Minkowski spacetime in a theory of quantum gravity change our understanding of the universe?

The use of k-Minkowski spacetime in a theory of quantum gravity does not necessarily change our understanding of the universe, but it does provide a more comprehensive and consistent framework for studying the fundamental laws of nature. It allows for a better understanding of the relationship between quantum mechanics and general relativity, and may potentially lead to new insights and discoveries about the nature of our universe.

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