Lorentz transform as a complex function

Click For Summary

Discussion Overview

The discussion centers on the representation of the Lorentz transform using complex functions and the exploration of alternative algebraic structures, such as hyperbolic numbers and quaternions, in the context of special relativity and electromagnetism. Participants examine the implications of these mathematical frameworks for understanding physical laws and their potential advantages over traditional vector calculus.

Discussion Character

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

Main Points Raised

  • One participant proposes representing the Lorentz transform as a complex function, but notes that traditional complex algebra does not permit this due to the Cauchy-Riemann conditions.
  • Another participant suggests that modifying the product rule in complex algebra could allow for a representation of the Lorentz transform, leading to a non-commutative algebra with unique properties.
  • A participant mentions the possibility of defining a four-dimensional differential calculus within this modified algebra, resulting in a mathematical object that resembles the electric and magnetic fields and the Lorentz gauge condition.
  • There is a suggestion that the laws of electromagnetism could be expressed as four-dimensional differential equations, potentially simplifying the solving process.
  • One participant introduces the concept of complex quaternions and their application to special relativity, proposing that they can unify Maxwell's equations into a single equation.
  • Another participant questions the reliance on partial derivatives and vector calculus in textbooks, expressing interest in the quaternion system as a simpler alternative.
  • Additional resources and alternative approaches, such as Geometric Calculus and differential forms, are shared by participants to explore further mathematical frameworks.

Areas of Agreement / Disagreement

Participants express various viewpoints on the representation of the Lorentz transform and the use of alternative algebraic structures. There is no consensus on the validity or utility of these approaches, and multiple competing views remain regarding the best mathematical framework for discussing these concepts.

Contextual Notes

The discussion involves complex mathematical concepts that may depend on specific definitions and assumptions, which are not fully resolved. The implications of the proposed algebraic modifications and their relationship to established theories remain unclear.

quaternion
Messages
4
Reaction score
0
I tried to represent the Lorentz transform which converts a pair of space-time co-ordinates (ct,x) to (ct',x') as a function of a complex variable i.e

ct' + ix' = f(ct + ix)

Unfortunately the rules of complex algebra do not permit this because the complex product is defined as

(a + ib)(c +id) = (ac - bd) + i(ad + bc)

Consequently the required function is prohibited by the Cauchy-Riemann conditions.

I have been investigating what happens if the rules of complex algebra are changed so that the product rule looks the same in form as the Lorentz transform i.e.

(a + ib)(c + id) = (ac - bd) + i(ad - bc)

This results in a non-commutative algebra in which the Lorentz transform can be represented as multiplication by a complex constant which depends on the relative velocity.
This seems to be a convenient language for doing these problems as Lorentz invariant quantitites can be represented as complex functions of the space-time co-ordinate without reference to any particular inertial frame.
The algebra has some unusual features e.g factorisation of zero and an infinite number of square roots.
Following W.R. Hamilton I extended the algebra to four dimensions [historically the origin of the modern vector calculus] making the same modification to the quaternion algebra as above. I defined a differential calculus for this algebra and formed the first derivitave of a scalar + vector potential [this looks like a Minkowski four-vector but the time component is real and the space components are imaginary].

The result is a mathematical object with 16 partial derivative terms six of these look like the expression for the electric field, six look like the magnetic field and the remaining four look like the Lorentz gauge condition. This suggests that the algebra can be used to make field equations again using only Lorentz invariant quantities.

Has anyone seen this approach before?
 
Physics news on Phys.org
Last edited by a moderator:
hyperbolic numbers

Thanks for that. The algebra I have got in mind not only permits division but it is possible to define a four-dimensional differential calculus.

If I make a four-dimensional potential function and take the first derivative I get a mathematical object consisting of sixteen partial derivatives, six of these look like the expression for the magnetic field six look like the electric field and the remaining four look like the Lorentz gauge condition. Does this mean any thing to you?

It occurred to me that it might be possible to write the laws of electromagnetism as four-dimensional differential equations.
The dimensionality is embedded in the algebra so the process of solving them looks like a one-dimensional equations.
As Hamilton said we could solve these problems 'without the aid of a co-ordinate system' [On Quaternions]. Do you think this makes any sense?
 
Last edited:
I'm not sure if this is anywhere near what you have in mind, but the complex quaternions can used to do special relativity. In this formalism: a 4-vector is a scalar plus a (3-)vector; Maxwell's equations can be written as one equation.

Regards,
George
 
Maxwell's equations

Thanks George.
Can you tell me what the equations look like in the quaternion algebra.

Do you know why all the textbooks use partial derivatives and vector calculus? The quaternion system seems so much simpler.
 
Last edited:
Home page

Hi,
If anyone is interested I posted my thoughts on this at

http://www.members.aol.com/csborrell/Index.html
 
Last edited by a moderator:

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 30 ·
2
Replies
30
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 15 ·
Replies
15
Views
2K