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## Main Question or Discussion Point

Hello everyone,

Still working on my reading of Weinberg's Lecture notes on QM book. At one point, the following integral $$\int d^3 xd^3 x' V(\vec{x~}) V(\vec{x'}) / |\vec{x~} - \vec{x'}|^2$$ has to be computed in the case where ##V(r) = -e^{-r/R}/r##. This reminds me of retarded potentials, but I don't have my other books with me, and cannot find a way to compute this integral. I've been trying with some residues, but this is unwieldy. The result should be ##8\pi^2 R^2##.

Thanks for any hints that would help me compute it.

Bye,

Pierre

Still working on my reading of Weinberg's Lecture notes on QM book. At one point, the following integral $$\int d^3 xd^3 x' V(\vec{x~}) V(\vec{x'}) / |\vec{x~} - \vec{x'}|^2$$ has to be computed in the case where ##V(r) = -e^{-r/R}/r##. This reminds me of retarded potentials, but I don't have my other books with me, and cannot find a way to compute this integral. I've been trying with some residues, but this is unwieldy. The result should be ##8\pi^2 R^2##.

Thanks for any hints that would help me compute it.

Bye,

Pierre