On a resource recommendations question, would it be appropriate to give a short introduction to the topic in addition to an overview of available sources?

@alemi I think there's nothing speaking against that, if you want to do it. It might even improve the idea of people reading it which resource to turn to.

@ACuriousMind Re the discussion the other day about Geometric Algebra, and your answer on the pseudovector question, I think this is an example of a place where if GA was taught from the get go, no one would be confused about pseudovectors, as they never enter.

@alemi True enough. And it also underscores your point that it would have to be taught before you ever see the "normal" notions of vectors and the cross product, since that is really the root of evil here: Many people using it are not even aware that it produces something which is not quite a vector.

@ACuriousMind strictly speaking, its a vector in the sense that its an element of a vector space, but so are $L^2$ integrable functions on a fixed domain. ;)

There ought to be a name for a physical vector, though the best I can come up with is 'pointy arrow thing'

@alemi Yeah, it's confusing that we have no real word for the "geometrical" vector as opposed to the abstract vector. Except for arrow, perhaps, but that's not really established, I think.

Great minds...

...think alike :D

and Hestenes would probably say that the elements of his vector space were the true 'arrows' and it's vector calc that is misleading everyone

Probably. Maybe the problem is that no "true" mathematician uses what we learn as vector calc. The algebraists all know about the exterior algebra, and regard things like the cross product as toys you give undergraduates, while the differential geometers use forms and wedges anyway, since $\mathbb{R}^n$ is just boring.

So most have, unlike Hestenes, no strong desire to change the pedagogy since it does not affect them personally

I really like Hestenes' other pedagogical research. I think the Force Concept Inventory has been a boon to physics education research. So in a lot of ways it's like the whole field of physics education research. Lots of interesting and cool ideas, but most professors can't be bothered to try them out, they just teach the way they were taught.

I must say I know next tonothing about that, but what a cursory googling shows looks like he's one of the few to really think on a broad scale about what it means to understand and not just regurgitate something

Random question: Anyone happen to know a family of random matrices that have power law distributed eigenvalues?

I seem to recall there being such a family but can't find it now

@ChrisWhite I wasn't really interested in sampling from the distribution. I was trying to figure out how to parameterize models y=f(x,theta), where df/dtheta had power law distributed eigenvalues. The more general the functional form the better. I was hoping that if I knew the name for the random matrix family, I could find people discussing models that produced that family.

s/eigenvalues/singular values/g

@ChrisWhite You must have better google fu than me. Thanks.

@ChrisWhite Actually, this is extremely helpful. Thanks a bunch.

You gotta love the Role-playing Games: Why is burying yourself not such a great plan?

"We're here to play a game of heroic fantasy. Tell me what part of this is heroic, or fantasy? It's really kind of weird."

Hey guys, I've been thinking about this idea for a while: Could we make a set of 'canonical questions' to refer people to, about certain topics that keep coming up

This was inspired by John Rennie's SRT 'reference question'

except for these we would try to make a question with a set of answers that cover different levels

qualitative-popular up to grad level (or even higher..)

@Danu: I like the idea in principle, but I think it would be difficult coming up with new "canonical" questions that would not be duplicates of old question. Maybe we could search for old ones though and make a concerted effort to give them the comprehensive answers that you have in mind

right

That's what I mean, really

to just provide a once-and-for-all place for these things

Uncertainty principle, Higgs mechanism

Then I think that would be a nice task for the community :)

:D

It will require some concentrated effort, like you said

so I want to get some momentum behind it

so maybe I should post it on meta?

I also need some more ideas for canonical questions

The twin paradox

If there's one thing we need a canonical reference for, it's that

yes

for sure

perhaps something about quantum gravity

I was just searching around the the twins paradox question we could try to clean up, and honestly they all try to raise some particular issue or subtlety. If we wanted a place where all of the relevant discussion was contained in one place, I think it would require a new question. Honestly, this was part of my proposal for the 'kapitza' questions, to create canonical references with lots of different variations discussed, all in one place, in order to create a canonical reference.

okay

What about something like: How should I think about the twin paradox? : The twin paradox [link] is a standard problem given in special relativity [link], but as one looks around for discussion of the phenomenon, one finds lots of different variants[link, link, link, link] and different interpretations..... But this would likely be considered too broad. Personally I think it would make a great page on the web, where we could consolidate all of the best answers together.

That sounds good to me

I think we could make something like this happen

Same could go for the uncertainty principle

Then in the future, people could link to those answers anytime they were needed, and most of the natural followup questions people would have would just be a simple scroll away, and if in the future anyone asked some new variant, you could close it as a dup and add a new answer to the canonical reference.

and even time dilation in SRT

yes

It would naturally have to be protected, and the community would have to make a real effort to make all of the answers be really top notch, with diagrams and quantitative calculations and the like. Heck, to keep points out of it, the question and all of the answers could be community wiki

I'm getting excited about this :D

Right

I think it could be very valuable

Or at the very least, we would have to be okay with editing other peoples answers more than we are now, at least as far as these questions are concerned

yeah just community-style

You should write up a proposal to Meta. See what happens. I like it, but I also liked my kapitza thing and that didn't go too well. Perhaps this is a better way to sell my actual goal, of making physics.SE more than just a place to find good answers to good questions and start to tap the community talent we have here to become a real reference on popular or interesting physics topics.

okay

I think people disliked the Kapitza thing because it sounds too specific

and kind of missed the point

I didn't sell it well. I'll admit that.

I think we could make this work

with you, me, ACuriousMind and a few others on board

Then again, the natural argument against your idea is, why don't we all just put these kings of things on wikipedia? I think the answer to that is that for the most part, is that we would have more freedom here to work through calculations step by step in a more pedagogical style than would be welcome on a wiki post. And obviously wiki, the great reference that it is, doesn't fill this need as we get tons of these near dups on classic questions.

an important part of my idea was hat there wwill be answers of different level

which I think is very important

which wiki cannot do

I'm just trying to answer the arguments against before they come up. I would spend some time really crafting the meta.

yeah

I will think about it some more

and keep you up to speed

What the heck is this: "The question you are asking appears to be subjective and is likely to be closed" just appeared beside the title of a question I was editing

Is the system intelligent enough to ascertain subjectiveness? I'm scared

This seems to be the natural seed for the twin paradox from 3 years ago.

good diggin' in the vaults, alemi!

@ACuriousMind Who knows what it is capable of?!

I have to go for now

@ACuriousMind On the podcast a while ago, they talked about they have some rudimentary filters in place to prevent really low quality posts, but for the most part they are just searching for particular words or phrases, do you have 'opinion' in your title?

or 'best'?

@alemi It was this question

I'm not seeing anything particularly subjective about the title

@ACuriousMind in the editor, if I remove the "Can you" the warning goes away, seems to be what is setting off the warning. In fact if I put 'can you' anywhere in the title it goes off, e.g. "Born probabilities can you that are irrational from an experiment?" or even just "banana can you muffin"

What would be a good stackexchange site to ask about the maximum number of arguments in the Excel STDEV function?

@GlenTheUdderboat perhaps Super User?

@ACuriousMind AH, thanks.

today I learned: "banana can you muffin" appears subjective and is likely to be closed.

@alemi Hm. Stupid thing to scan for, in my opinion. "Can you detect X?" is a perfectly reasonable, objective question title

Haha

They don't forbid you from asking that, and I imagine the filters are mostly created by people based off of behavior on SO, where "can you" is much more likely to be subjective than on a science SE.

@Danu useful search for preparing evidence: here

@ACuriousMind How's it going mate?

@Phonon Quite well :) And listening to the thunderstorm outside makes me happy to be at home.

@ACuriousMind haha :)

@ACuriousMind yeah apparently in UK as well the weather's been terrible

@Phonon Well, it's not that bad here. But I find the sound of raindrops on the roof and thunder in the distance quite soothing

@ACuriousMind indeed, specially the rain in the mornings,

@ACuriousMind any questions you found interesting today? among the recent posts

@Phonon Pretty "meh" day so far, I must say. The only kinda interesting one about spinor reps was a duplicate, and the rest is not really what I'd call interesting.

@ACuriousMind alrighty :(

Though this one could be on to something. I'll have to think about it a bit - as with all things QFT, it could also have a really silly answer.

ah cool, thanks for the link, I'll have a look too, although it's miles away from my field :)