@qwerty JD Jackson is better, but beginners should not be starting with a graduate book. Especially for those who are not used to the maths of vector calculus and all, Jackson is just wayyyy too difficult. Griffiths was very happy when miao miao emailed him to thank him for his nice little book. @SirCumference his QM book is nice too, a simplification of others, just like his EM was a simplification of Jackson. Sadly he didn't use bra-ket.
@naturallyInconsistent JD Jackson's uses the term quasistatic for his derivation of work done against induced E fields (the derivation for $\frac{1}{2\mu}B^2$) which assumes quasistatic motion of the charges in loops. The derivation for poyntings theorem doesn't assume such things, though, and that's the canonical energy conservation in Classical EnM
@naturallyInconsistent The greens functions chapter in JD jackson was where I found it yes, perhaps you are correct: I was wondering how green being from the 1800s correctly made use of this sifting property of the dirac delta
fair enough, so I dug up JD Jackson and showed that there was no mention of this averaging. (It only talks about the fact that you need to average, and that time averaging alone is not enough, you MUST have space averaging, and no helpful way to actually do this averaging)
You need to understand it about as good as the little section in JD Jackson on the averaging, and the scheme that is in Kittel's Intro to SSP. Then you should be able to understand what is being covered.
@ACuriousMind thank you. out of curiosity which books actually motivate the idea? jd jackson and griffiths dont spend time on it (atleast when they introduce it)
JD seems at heart to be questioning the physics validity of the field... indirectly. but not exactly with those words. if quantum computers are merely hype, then they surely cant be real physics either... there is some overlap with Dyakonov sentiments, a phd physicist. JD might be referring to physicists working in QC as "quantum quacks."
A more comprehensive answer to JD's question on why there are no composite photons: Because they are not bosons (as well other inconsistency issues discussed back in 2014 with Acuriousmind and co.)
It also mean that, even if JD's or more generally, the "time is illusion" philosophy camp is correct, there will be nothing stopping time travel to become possible
@RyanUnger JD's version of Einstein's version. :) But as John Rennie just said, even old Albert himself didn't have a flawless grasp of GR. But that's quite understandable. It takes a while for new paradigms to properly settle into the landscape.
@ACuriousMind Anyway, I've posted an answer. Not a good answer, but I hope at least enough of an answer to reassure the OP that JD isn't representative of the site membership.
@JohnRennie I agree it deserves a good answer. I assume that the test mass can only make the curvature worse, but as the OP says, it'd be good to see some actual maths. JD's answer isn't unexpected, he can't help himself with questions like this.
@RyanUnger On the bright side, if JD agrees with a post about relativity, that's a good indication that it's probably wrong. ;) Pity that the converse isn't always true...
More wisdom from JD: "A lot of people claim that a flat universe must be an infinite universe. But it's a non-sequitur." From astronomy.stackexchange.com/a/32469/16685
This guy keeps posting his theory that light increases its speed as it heads away from a massive body (& vice versa). He also does it on Astronomy, where JD encourages him. :(
Anonymous
Feb 10, 2019 14:16
I deleted all of JD's answers on QCSE manually.
user351417
Feb 10, 2019 14:15
To be fair, JD had 7k rep, right? There's no argument in "he had 4k rep"
