Form of Lorentz Transformation Using West-Coast Metric

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Discussion Overview

The discussion revolves around the form of the Lorentz transformation matrix and its dependence on the convention used for the Minkowski metric, specifically contrasting the West-coast and East-coast metrics. Participants explore whether the transformation's form is influenced by the metric convention in theoretical physics.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that the Lorentz transformation matrix is dependent on the metric convention, citing a specific form for the West-coast metric.
  • Another participant argues that the form of the Lorentz transform does not depend on the metric convention, stating that the matrices provided are inverses corresponding to boosts in opposite directions.
  • A third participant reinforces that the Lorentz transformations are defined in a way that the metric does not affect the transformation, referencing a mathematical equation that supports this view.
  • A later reply expresses a sense of relief and acknowledgment of the clarification provided by others.

Areas of Agreement / Disagreement

Participants express disagreement regarding the dependence of the Lorentz transformation on the metric convention, with some asserting it does not depend on the metric while others initially believed it did. The discussion remains unresolved as differing interpretations are presented.

Contextual Notes

The discussion includes assumptions about the definitions of the metrics and the implications of using different conventions, which are not fully explored or resolved.

LittleSailor
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This is a fairly trivial question I think. I'm only asking it here because after some googling I was unable to find its answer. I was at one point led to believe that the form of the Lorentz-transformation matrix is dependent on the convention used for the Minkowski metric. Specifically it was my understanding that

[γ, βγ, 0, 0]
[βγ, γ, 0, 0]
[0, 0, 1, 0]
[0, 0, 0, 1]

was the transformation matrix when the West-coast metric, diag(1, -1, -1, -1), is used. This is the inverse of the more commonly encountered

[γ, -βγ, 0, 0]
[-βγ, γ, 0, 0]
[0, 0, 1, 0]
[0, 0, 0, 1]

which I know is correct at least for the East-coast metric, diag(-1, 1, 1, 1). I was working a problem recently and got a result using the former of these transformation matrices that was clearly incorrect. Does the Lorentz transformation's form actually depend on the convention for the metric, or did I concoct this entire distinction? Perhaps I misunderstood one of my professors.
 
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The form of the Lorentz transform does not depend on whether you use +t metric or -t metric. The two transform matrices you give are simply inverses of each other corresponding to boosts in opposite directions.
 
As a group the lorentz transformations, \Lambda^{\mu}_{\nu} are defined by:

\begin{equation}
\Lambda^{\mu}_{\nu} \eta_{\mu \rho} \Lambda^{\rho}_{\sigma} = \eta_{\nu \sigma}
\end{equation}

Thus, the metric should not affect the transform because you can multiply both sides of the equation to switch metric convention.
 
Haha, I feel silly now--thanks, guys.
 

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