Minkowski Metric
The Minkowski metric, also called the Minkowski tensor or pseudo-Riemannian metric, is a tensor eta_(alphabeta) whose elements are defined by the matrix
where the convention c=1 is used, and the indices alpha,beta run over 0, 1, 2, and 3, with x^0=t the time coordinate and (x^1,x^2,x^3) the space coordinates.
The Euclidean metric
gives the line element
while the Minkowski metric gives its relativistic generalization, the proper time
The Minkowski metric is fundamental in relativity theory, and arises in the definition of the Lorentz transformation as
| Lambda^alpha_gammaLambda^beta_deltaeta_(alphabeta)=eta_(gammadelta), |
(7)
|
where Lambda^alpha_beta is a Lorentz tensor. It also satisfies
| eta^(betadelta)Lambda^gamma_delta=Lambda^(betagamma) |
(8)
|
| eta_(alphagamma)Lambda^(betagamma)=Lambda_alpha^beta |
(9)
|
| Lambda_alpha^beta=eta_(alphagamma)Lambda^(betagamma)=eta_(alphagamma)eta^(betadelta)Lambda^gamma_delta. |
(10)
|
The metric of Minkowski space is diagonal with
and so satisfies
| eta^(betadelta)=eta_(betadelta). |
(12)
|
The necessary and sufficient conditions for a metric g_(munu) to be equivalent to the Minkowski metric eta_(alphabeta) are that the Riemann tensor vanishes everywhere (R^lambda_(munukappa)=0) and that at some point g^(munu) has three positive and one negative eigenvalues.
See also
Euclidean Metric, Line Element, Lorentz Tensor, Lorentz Transformation, Minkowski SpaceExplore with Wolfram|Alpha
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References
Weinberg, S. Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity. New York: Wiley, p. 38, 1972.Referenced on Wolfram|Alpha
Minkowski MetricCite this as:
Weisstein, Eric W. "Minkowski Metric." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/MinkowskiMetric.html