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May 31, 2021 at 14:56 vote accept SaMaSo
Jul 11, 2019 at 14:19 comment added Lorenz Mayer You are right. Of course there are IR divergencies in $d=1$. I added this part.
Jul 11, 2019 at 14:18 history edited Lorenz Mayer CC BY-SA 4.0
included the case $d=1$.
Mar 1, 2019 at 21:12 history bounty ended SaMaSo
Feb 28, 2019 at 11:54 history edited Lorenz Mayer CC BY-SA 4.0
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Feb 28, 2019 at 11:27 comment added SaMaSo I think Kardar's is different than dim regularization because his result does have IR divergencies for d=1,2.
Feb 28, 2019 at 11:24 comment added SaMaSo Thanks, Lorenz. Could you please edit your answer reg UV divergencies, explicitly stating in d=2,3,4 the bound is not useful and for higher dimensions, the oscillations don't kill the integral and we need regularization? Then I can accept your answer.
Feb 28, 2019 at 11:16 comment added Lorenz Mayer Kardar, i would assume, uses dimensional regularization from the beginning, even when no regularization is needed. Then you have to remember that dimensional regularizing an integral removes all but logarithmic divergencies.
Feb 28, 2019 at 11:14 comment added Lorenz Mayer That is true. The oscillations will make a integral divergent whose integrand has some decay.
Feb 28, 2019 at 11:12 comment added SaMaSo It still remains obscure how Kardar's approach is removing these divergencies all at once. But your answer has been really helpful
Feb 28, 2019 at 11:10 comment added SaMaSo I see. So the initial bound that you were trying to improve wasn't a meaningful one for d=2,3,4. For higher dimensions, however, the integral is indeed UV divergent and needs regularization, and the intuition that the oscillations cancel each other doesn't really work. Is that correct?
Feb 28, 2019 at 11:04 comment added Lorenz Mayer There are no UV divergences in the physically interesting cases of d=1,2,3,4.
Feb 28, 2019 at 11:03 comment added SaMaSo This is getting perfect. So when you say "for all other d the integral is divergent and one has to introduce a regularization" I guess you mean UV divergence right? Then "So we see that there are no UV-divergencies really" is not accurate anymore.
Feb 27, 2019 at 17:23 history edited Lorenz Mayer CC BY-SA 4.0
added 457 characters in body
Feb 27, 2019 at 16:55 history edited Lorenz Mayer CC BY-SA 4.0
added some comments on IR-divcergence in 2d
Feb 27, 2019 at 16:15 comment added SaMaSo Thanks for the edits. Nice note on alternating series. For the $d=2$ case, should we not recover a logarithmic potential? Also, $d=4$ case is interesting. I have to brush up my Bessel functions education:) Btw, do you have any ideas as for how to develop this calculation for higher dimensions?
Feb 27, 2019 at 13:52 history undeleted Lorenz Mayer
Feb 27, 2019 at 13:52 history edited Lorenz Mayer CC BY-SA 4.0
the previous version had a fatal mistake in its argument.
Feb 27, 2019 at 13:28 history deleted Lorenz Mayer via Vote
Feb 27, 2019 at 13:25 history edited Lorenz Mayer CC BY-SA 4.0
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Feb 26, 2019 at 17:33 comment added SaMaSo Thank you for your answer. I think I'm not following when you introduce variable $u$. Should the integrand not be $(1-u^2)^{(d-3)/2} \, du$ instead?
Feb 26, 2019 at 13:26 history answered Lorenz Mayer CC BY-SA 4.0