Quaternions & Octonions: Definition & Uses

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Discussion Overview

The discussion revolves around the definitions and applications of quaternions and octonions, exploring their mathematical properties and physical uses in various fields such as quantum mechanics, relativity, and computer graphics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants seek definitions of quaternions and octonions, noting their algebraic properties and multiplication rules.
  • Quaternions are described as an extension of complex numbers, with some participants expressing surprise at their applications beyond pure mathematics.
  • Physical uses of quaternions in quantum mechanics and relativity are mentioned, with references to specific literature and applications.
  • There is a discussion about the use of quaternions in 3D programming, particularly for camera classes, with some arguing that vector algebra could achieve similar results.
  • Historical context is provided regarding Maxwell's original formulation of electromagnetics in terms of quaternions, and the subsequent debate over their necessity compared to vector-based approaches.
  • Some participants note that quaternions have reappeared in physics through matrices and Clifford algebra, particularly in quantum mechanics.
  • There is mention of the limitations of quaternions in expressing certain geometrical concepts and relationships in physics, suggesting that other mathematical frameworks may be more suitable.

Areas of Agreement / Disagreement

Participants express a mix of curiosity and skepticism regarding the utility of quaternions and octonions, with some agreeing on their mathematical significance while others question their practical applications. The discussion remains unresolved with multiple competing views on their relevance and effectiveness.

Contextual Notes

Some claims about the historical use of quaternions and their applications in various fields are presented without consensus on their effectiveness compared to other mathematical tools. The discussion includes references to specific literature and personal interpretations of the material.

marlon
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Can anyone give me a definition of quaternions and octonions? What are these things and what are they used for.

regards
marlon
 
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Nenad said:
chech this site out. It gives a good mathematical interpritation:
http://mathworld.wolfram.com/Quaternion.html


So they are basically elements of some algebra with specific multiplication-properties. The Pauli-matrices who obey these rules are quaternions...

ok, can anyone give some more physical uses of these things


thanks, nenad for your quick repley

regards
marlon
 
looks like it can be implimented in quantum physics... have a look here, it's all way over my head and I didnt read much of it, but they're certainly using quaternions! :rolleyes:
 
Dominguez Scaramanga said:
looks like it can be implimented in quantum physics... have a look here, it's all way over my head and I didnt read much of it, but they're certainly using quaternions! :rolleyes:


This is what i was looking for...

grazie, grazie, grazie

marlonissimo
 
marlon said:
This is what i was looking for...

grazie, grazie, grazie

marlonissimo

no problem :smile:
 
The short answer is that they are an extension to complex numbers. It is apparently a quite "natural" extension. I didn't know they were useful for something else than pure math, especially not QM!
 
Gonzolo said:
I didn't know they were useful for something else than pure math, especially not QM!

ahh the wonders of google :wink:

... there's even a quaternions.com!
 
They have been used in Reletivity Theory successfully. See the books by Mendel Sachs.
 
  • #10
Quaternions are also used by 3d programmers a lot for "camera" classes. Many people now argue that these things are useless because vector algebra and calculus can do the exact same thing. It is my understanding that this is a precurser to that branch of mathematics.
 
  • #11
Maxwell's original formulation of Electromagnetics was in terms of quaternions but there were several individuals such as Gibbs and Heaviside who questioned the necessity and pragmatics of using quaternions and promoted a version employing only VECTORS. The dispute got quite heated with insults being hurled back and forth. In NEW FOUNDATIONS FOR CLASSICAL MECHANICS, Dr. David Hestenes mentions this controversy and how quaternions reappeared in physics in the form of MATRICES and CLIFFORD ALGEBRA in Quantum Mechanics. (http://modelingnts.la.asu.edu/GC_R&D.html )
Quaternions have been used very extensively by engineers and computer programmers for modelling rotations as mentioned in some of the other postings.
Expressing GTR in a quaternionic formulation is at the root of Mendel Sach's approach to a unified theory of electromagnetism and gravity but quaternions are not a comprehensive mathematical language for expressing geometrical concepts and relations in physics. Some relationships such as between Yang Mills theory and GTR show up better when expressed in Geometric Algebra.
 
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