- #1
ohwilleke
Gold Member
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Most often, general relativity is formulated in terms of Einstein's field equations:
whose terms are familiar to readers in this forum.
But, I understand (and feel free to correct me or qualify my statement if I am incorrect) that it is also possible to describe general relativity with an equivalent expression known as the Palatini action sometimes written as:
where
but now
is a function of the frame field.
The Palatini action is used, for example, in a recent pre-print by SangChul Yoon, "Lagrangian formulation of the Palatini action" (May 5, 2018).
What are the insights or mathematical benefits that are involved in using the Palatini action? What are the disadvantages to using this formulation of general relativity?
But, I understand (and feel free to correct me or qualify my statement if I am incorrect) that it is also possible to describe general relativity with an equivalent expression known as the Palatini action sometimes written as:
where
The Palatini action is used, for example, in a recent pre-print by SangChul Yoon, "Lagrangian formulation of the Palatini action" (May 5, 2018).
What are the insights or mathematical benefits that are involved in using the Palatini action? What are the disadvantages to using this formulation of general relativity?