In a probably misguided effort to make a definitely misguided effort on my part right, I've marked this answer: physics.stackexchange.com/a/130381/51994 as community wiki. Perhaps it can serve as a sink for various questions on temperature and absolute zero

anyone bored? physics.stackexchange.com/questions/130750/…

:)

@MarkMitchison You stumped me with "A longitudinal wave is naturally modelled as an excitation of a scalar field, while a transverse wave corresponds to a vector field" AFAIK, arbitrary vector fields can exhibit both longitudinal and transverse polarizations. It is just that the EM field is a gauge field, and there the ghosts incurred by the wrath of Fadeev-Popov kill off the non-transverse excitations (make them "unphysical" in BRST quantization).

right

good point

but if it's transverse in 3D

it has two polarisation modes

.....

ha

yeah but that's why it's a gauge field

hmmm

so a vector field naturally has 3

Lorentz gauge field only 2

sorry just thinking out loud

I guess my point was that a transverse field is not in the trivial representation of the transformation group

but exactly what it is of coure depends on whether we are talking about rotations or the full Lorentz group

OK have updated the question

I think it is a good question though, and possibly has some kind of insightful answer

I'm not sure if it's any more clear now

Yeah I was hoping that someone who is a bit more savvy with field theory and group reps could blow my mind :)

@MarkMitchison I think you could try to make progress, assuming a form $ L(\phi(x,y,z,t)) = \delta'( 0 ) e^(i\omega t) $ where $L$ is some linear operator. It sounds like you are asking something like: Assuming $L$ forms a representation of SO(3), given that the source breaks the symmetry in the $x$, can we say anything about the symmetry of the solutions.

The time dependence of the problem is making it hard for me to reason though

I don't know how to express the symmetry of the dipole, but if you knew the group and its irreps, you could decompose whatever representation $\phi$ gave onto those irreps and get an idea of what terms could and could not appear

or something

I'm not a field theorist though

@alemi Thanks, that sounds like a reasonable strategy. I'll let you know how I get on.

Wow... Lubos just reached 100k :D

Is there any good reason why I can't vote on posts in the VLQ queue?

@ACuriousMind There probably is, what it is specifically is unknown to me...

Here's one feature request on the mother meta

@EmilioPisanty: Thanks, that led me to Shog9's answer here. I'm not fully convinced though that I can't decide what to up-/downvote without seeing the other answers - am I really supposed to vote something up if it is "the best available" even if it is terribly wrong or unclear?

As a short-cut/hack, you can always shift-click the title of the question (always visible) and vote on the page

Yeah, but then I'll have to make that effort :P (I do it mostly, anyway)

It's not that much effort

BRB, gotta head to the library.

It's strange to go into the very basement of the Library

They have those shelves that roll around

Still afraid I'm going to squish someone

@KyleKanos The archivar's only reaction would probably be: "Shhhh!"

archivar = librarian?

Yeah, that's the word I was looking for

Okay

I figured it had to be that

Looking it up, it seems archivars are people who compile the archives, which librarians not necessarily need to have done

I don't know why the association library -> librarian was a bit difficult for me to make :D

I figured from the "Shhhh!" comment that it had to be librarian

@ACuriousMind Sorry if I came off as a jerk yesterday, didn't mean to be a jerk. I need to learn how to use more emoticons. Never liked emoticons though.

@alemi Don't worry, I do not think of people as jerks who reasonably make their points. :)

@ACuriousMind There are also archivists.

@alemi Now that I look at it again, I see that archivar is not an English word at all. It is simply the German word for archivist.

@ACuriousMind I thought that my questioning the meaning would have signified that it was not an English word

@KyleKanos Yes, but since misread some of the dictionary results I looked up, I got the impression it was simply a bit obscure. Turns out it was my reading comprehension that was a bit obscured

hi

hi

hi

I would just like to note I love the name of this chat room.

It's true, I smile every time I read it

The h Bar - getting drunk on physics?

@Kyle I like it, though the intoxication by physics is more lofty than begin merely drunk ;)