- #1
Bartolius
- 7
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Homework Statement
I have to write equations of motion for a field, namely ## A ##.
The full action has actually three terms, but my problem is with a part of the action reading:
$$ S =\int d^{10}x \sqrt{-g} [ f(x_1, ... , x_{10}) + \delta (y) A ]^2 $$
In the 10 x's there is of course the coordinate called y. Also I omitted various irrelevant numerical factors.
Homework Equations
My problem is that the product of ## \delta ##'s , in particular ## [\delta (y)]^2 ## is not defined for they are distributions and not simple functions, so I don't actually know how to write down my equations.
The Attempt at a Solution
The only idea I have right now is to replace the deltas with something approaching the delta in a certain limit and then take the limit at the end of the calculations, but having done some research on the internet it seems to turn out that the result would be dependent on my choice of the function approaching delta. I can recall having found a similar problem in one of my first courses on QFT, but can't recall how it was solved. However it seems a rather common problem, so I hope that someone here already has a solution and can lead me to find it.