1
$\begingroup$

Is there a similar version of the summation theorem for spherical Bessel functions $j_{k}$ that of standard Bessel function $J_{k}$? Especially look below Eq.(3) in this paper https://arxiv.org/abs/cond-mat/0510271 for $J_{0}\left(\left|p-p'\right|r\right)$.

$$J_{0}\left(\left|\vec{p}-\vec{p'}\right|r\right)=\sum_{k=-\infty}^{\infty}J_{k}\left(pr\right)J_{k}\left(p'r\right)\cos k\theta$$

where $\theta$ is the angle between the two vectors in the plane.

I am interested to know whether a similar expression exist for $j_{0}\left(\left|\vec{p}-\vec{p'}\right|r\right)$, where the vector lies in three dimension.

$\endgroup$
3
  • 5
    $\begingroup$ This seems more like a straight mathematics question. $\endgroup$ Commented Sep 29, 2020 at 3:34
  • $\begingroup$ I believe the Bessel function is extensively used in Physics. I am rather looking for an identity, not a proof :) $\endgroup$ Commented Sep 29, 2020 at 4:08
  • $\begingroup$ I'm quite sure the nice Mathemathics SE people will provide that info - they don't enjoy typing long proofs any more than we do here. They are, however, far more likely to have members familiar with every obscure mathematical relationship than we are. $\endgroup$ Commented Sep 29, 2020 at 4:35

1 Answer 1

3
$\begingroup$

The identity you seek is

$$j_0(|\vec{p}-\vec{p}\,'|r)=\sum_{n=0}^{\infty}(2n+1)j_n(pr)j_n(p'r)P_n(\cos\theta).$$

It follows from (10.60.2) here.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.