Harmonic Coordinates
A particularly useful coordinate condition is the harmonic condition (also known as the "de Donder gauge"):
Here, gamma is a Christoffel symbol (also known as the "affine connection"), and the "g" with superscripts is the inverse of the metric tensor. This harmonic condition is frequently used by physicists when working with gravitational waves. This condition is also frequently used to derive the post-Newtonian approximation.
Although the harmonic coordinate condition is not generally covariant, it is Lorentz covariant. This coordinate condition resolves the ambiguity of the metric tensor by providing four additional differential equations that the metric tensor must satisfy.
Read more about this topic: Coordinate Conditions
Famous quotes containing the word harmonic:
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—Kyle D. Pruett (20th century)