The h Bar

Joshua Lin

02:01

"The introduction of numbers as coordinates [..] is an act of violence whose only practical vindication is the special calculatory manageability of the ordinary number continuum with its four basic operations" - Weyl apparently
yikes

Joshua Lin

02:44

what is the 'correct hot take' to take on the aharonov bohm effect? In an effort to understand the gauge stuff I picked up a book - and the best I can parse it is:
- classical EM Gauge theory tells us that the gauge potential is not observable and we have gauge freedom
- quantum mechanics tells us the gauge matters in some experiments (where space is not simply connected ; this is not true of real space though?)
- therefore... what? the gauge theory viewpoint of classical EM is not completely compatible with QM? (I thought they merge and become QED?)

Avnish Kabaj

04:38

@vzn Spicy

user351417

04:56

@ACuriousMind Of course,I didn't exactly make up any of those rules. Most of them are general etiquette things which get called out or mentioned in other guides. I hope they don't become too rigid; if someone slips and breaks one of those every now and then, it really shouldn't be an issue. I hope that stuff's only for preventing people from being perpetually disturbing.

user351417

It depends on how we implement them. Like if we start pushing out suspensions (or even mod-message warnings) for every little thing, this chat'll deteriorate.

user351417

Tell me when I should accept my answer, presumably that would mark my answer as official. Shall we say after a certain number of days pass without a well-received alternative?

user351417

Also, are the modifications I made based on the stuff in your answer appropriate?

vzn

guys! great to see the interest in building up chat and the meta votes show there is interest. however there seems to be a mixing up of means and ends. somehow, maybe originating in blues post there seems to be an idea that formulating policy will somehow increase chat engagement or popularity maybe by being more hospitable to experts. this is an idea that circulates a lot on SE sites also wrt main site engagement. it may be more valid on main site but think it is less applicable to chat...

@AvnishKabaj lol hey jeffie welcome to your new potential crazy inlaw, ack! things are already turning ugly thedailybeast.com/…

Avnish Kabaj

06:22

@vzn Heh heh

@vzn +1

Ry-

06:57

Anyone want to reexamine/apply the rest of physics.stackexchange.com/review/suggested-edits/56244? I think it’s still valid.

John Rennie

07:07

@Ry- I think your edit looks fine. I don't understand why it got rejected.

Do you want to redo it, or I can do it if you want.

David Z

08:19

I'm not sure why it was rejected either. @Ry- you could probably get some insight by asking on meta.

user351417

08:47

@vzn I'm not expecting a huge boost in chat with the formulation of rules... it's just to make things convenient and stop new and old users from being driven away by something or the other.

user351417

Getting new people is a completely different matter. Perhaps a community ad would do that.

Mo_

09:50

@JohnRennie this might be interesting for you

John Rennie

@Mo_ :-)

My father is from Northern Ireland, though he completely lost his accent.

Mo_

"raining cats and dogs" means a heavy rainfall?

wow!

John Rennie

I'm not from the south east, but that's about right for my accent. I basically speak BBC English, and that's close to the south east English.

Mo_

@JohnRennie Nice match!

Mine was almost random :)

I didn't know half the words

John Rennie

Until I was nine we lived in the Sudan where my dad was working. The English I learned was basically the British embassy English.

Then I went to a school where the teachers were all very concerned that we speak properly.

Slereah

10:02

I'm not a brit but let's see what is my brit dialect

Oh no I'm Irish apparently

although not very

or a Londoner

John Rennie

I have a YouTube video of me speaking somewhere if you're curious about my accent (I don't suppose anyone is).

Slereah

Well depends what the video is aboot

My fake Britishness

you can tell I'm a fake brit because nothing is very bright

John Rennie

E6530 boot problem

►

Mo_

lol
mine was almost the same (the result was "**Way off**. Your answers didnt fit here at all.")

@JohnRennie We're all curious minds here

Slereah

I guess it's the kind of stuff you get when you mostly know English from American English

@Mo_ especially @ACuriousMind

John Rennie

10:11

It's remarkable how different your own voice seems when you hear it froma recording.

Emilio Pisanty

@Mo_ ah, gotta love the wean

I've never seen anything quite as Scottish as that

Anonymous

@Mo_ Seems to work just fine. :P

John Rennie

@EmilioPisanty I do like the Scottish dialect. Note that different parts of Scotland have very different dialects.

Anonymous

@Mo_ It's a pretty common expression (idiom) I think.

Slereah

10:13

Well it's not too common

but it's well known, certainly

Anonymous

Albeit the etymology is unclear.

Slereah

It's a bit old fashioned

Mo_

@Blue never heard that (my vocabulary is limited to around 10k)

PM 2Ring

My maternal grandpa was born in London, but the family emigrated to rural NSW, Australia, when he was 7, so he soon lost his Cockney accent. But he was well-spoken, and didn't pick up a strong Aussie country boy twang. And sometimes people think I'm English from my accent. :) AFAICT, I don't speak "posh"; I suppose I have a fairly typical middle-class Sydney accent.

Slereah

I speak with a comical french accent

Anonymous

10:17

9

A: The etymology of the phrase "it's raining cats and dogs"

There are a few theories, that's for sure. But the bottom line is, the etymology is unknown. I won't leave you without these pointers, though: The Phrase Finder: This is an interesting phrase in that, although there's no definitive origin, there is a likely derivation. [...] The fact that [...

John Rennie

@Slereah Zut alore!

Slereah

*alors

John Rennie

Shrug :-)

Emilio Pisanty

ah

those unused slots just mean that I didn't spend enough time in the UK to practice the full range

PM 2Ring

@Slereah :cues Monty Python's Holy Grail lines:

Anonymous

10:18

Pissing down? Do Brits actually use that? XD

John Rennie

Yes, though not in polite company.

Emilio Pisanty

John Rennie

I wouldn't say that to the Queen.

PM 2Ring

@Blue Aussies certainly do.

Emilio Pisanty

although this does indicate that I learned to talk about rain in the southeast =P

Mo_

10:20

@EmilioPisanty that's almost everywhere except Ireland

Emilio Pisanty

@Mo_ well, it rains everywhere

Slereah

@JohnRennie Damn servile

PM 2Ring

When a Japanese car factory explodes, it rains Datsun cogs.

Slereah

don't get crushed by her jackboots

I'm pretty sure Australians would say that to their prime minister

Emilio Pisanty

well, that's definitely curious

that is extremely unlikely to be close to what anyone thinks of my accent

Slereah

10:22

@EmilioPisanty well as you can see

everything is pale

PM 2Ring

@JohnRennie Indeed! It's nowhere as rich without the direct bone conduction of the sound.

Slereah

hence not very well correlated

Emilio Pisanty

still

I really don't think I sound remotely close to either Irish or from Edinburgh

Slereah

Me either

not even drunk

Anonymous

@PM2Ring Yeah, that's probably the main reason. There's also this.

Emilio Pisanty

10:26

here's some video, hear for yourself.

@JohnRennie Where in the UK would you put my accent?

John Rennie

@EmilioPisanty nowhere in the UK. You sound almost stereotypically Latin American to me.

Emilio Pisanty

@JohnRennie seriously?

fair enough

I don't get that very often

PM 2Ring

@Blue Good point, although if you're a singer or actor (or public speaker) that gets modified to an extent, since you learn how to witness your performance without messing it up.

John Rennie

Bear in mind I know no Spanish so my ability to distinguish between the different flavours of Spanish is minimal.

PM 2Ring

@Slereah Depends on the prime minister. An ocker bloke like Bob Hawke, no worries. We do have a polite form: "It's persisting down".

Anonymous

10:33

Emilio's sounds somewhat similar to the husky Indian voice...I'd certainly describe it as "husky" anyway.

Slereah

@PM2Ring I'm afraid all prime ministers in Australia are this man

The Simpsons - HEY MR PRIME MINISTA!

►

Anonymous

Definitely more like Latin American (basing this on my limited exposure to British and Latin American accents).

Slereah

Here is a delightful hate song for Canada, too :

MST3K - The Final Sacrifice: The Canada Song

►

Anonymous

It's interesting that I find some of the word sounds garbled in Emilio's accent.

Mithrandir24601

"What do you call the evening meal"... Um, all of the above?

Slereah

10:40

well click on all of the above

PM 2Ring

@Slereah Not quite. :) There were tiny fragments in that clip that sounded Aussie, but mostly it sounded like bad English accents. But I know it can be hard for Americans to hear the difference.

One of my high school science teachers was from New York. He said it took him a year of being in Australia before he could notice the difference between Aussie & British zccentz.

Mithrandir24601

@Slereah It was one of the 'you can only click on one option' things

PM 2Ring

Speaking of Hispanic accents, I quite like the Catalan sound of the kids in the Sant Andreu Jazz Band. They have a ton of clips on YouTube, and the audio quality of the clips is mostly quite good, although some are not so great, especially the outdoor performances.

PM 2Ring

11:04

This got bumped by Community a little while ago. physics.stackexchange.com/questions/175569/… It has 1 answer, but it's link-only, with zero score. Do I flag the answer as Very Low Quality?

Anonymous

@PM2Ring Alternatively, you could raise a custom flag and explain the issue.

Anonymous

> Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference.

Anonymous

I use this comment template for link-only answers.

Anonymous

I'm a bit hazy on whether the VLQ flag would apply in this case (i.e. for link-only answers), on Physics. On Quantum Computing, it certainly would.

PM 2Ring

@Blue I have something like that in a userscript on my computer, but not on my phone.

I often link to the "Your answer is in another castle" on SE meta.

Anonymous

11:20

@PM2Ring I like that one. :)

Anonymous

I refer to it when users come complaining about their deleted link-only or reference-only answers.

PM 2Ring

I won't flag for now. The author hasn't posted on Physics for a year, but is still active on the network, so I'll see how he responds to my comment.

Anonymous

Yeah, fair enough.

Anonymous

If they don't reply (which seems likely) it might be better to convert the answer to a comment.

PM 2Ring

On SO, I downvote & delete-vote link-only answers, but I'm not so inclined to delete if it's the only answer. And I always comment first, to give the author a chance to fix it, if they're still active.

But SO is a different place, with customs (kind of) appropriate to a coding site. And I try to pay attention to the differences between the different SE communities.

Anonymous

11:33

We do it a bit differently (on QCSE) i.e. we convert such answers to comments, first.; then we delete them and leave behind a comment requesting them to edit it and flag or ping us when they're done. That way, the information content of the answers still remain in the comments. And the deleted answers act as negative reinforcements in the meantime.

PM 2Ring

That gets done a bit on SO too, if the link has good info.

Anonymous

I suppose it doesn't scale well on SO as "converting to comment" is a mod-only privilege.

PM 2Ring

At least with coding info, you can often test it to see if it's correct, but not always. Code may appear to do what you want, but actually contain flaws. And people copy SO code without testing it properly. This has led to expensive &/or embarrassing problems, not to mention dangerous security holes.

Anonymous

> And people copy SO code without testing it properly.

Anonymous

No doubt. :)

PM 2Ring

11:43

@Blue True, and we try to avoid loading stuff onto the mods if we can deal with it at the community level. Quite a few of the Python room regulars have gold tag badges, and 20k+ rep, which is handy.

It scares me to think of how many websites are prone to SQL injection attacks. But newbies persist in writing vulnerable code in their answers. It's like fighting a hydra, for each newbie answerer you manage to educate, 3 more clueless newbies appear. :(

One funny story: a Python room regular also writes Java, and has developed some Android apps that are in the Playstore.

A few years ago, he posted working code on SO that came from his popular baseball card collector's app. That code had a string in it that's basically a public registration key for the app. He didn't think to modify that string, since it's public info.

Anyway, a few years later, he went to install his app to his brand new Samsung Galaxy phone, but it failed with a bizarre error message, complaining that the key was in use by Bixby, Samsung's AI thingy, a bit like Siri.

It turned out that one of Samsung's Bixby devs copied my friend's code off SO, and used it without modifying it, so it still had my friend's public key in it! :facepalm: IOW, it was a twisted accidental form of identity theft.

Anonymous

12:13

@PM2Ring LOLOL! This needs to be published somewhere. :D

PM 2Ring

@Blue It is! Give me a minute... I'm a bit sleepy, so I didn't think to do a search instead of typing out all that stuff. :)

xda-developers.com/…

Anonymous

@PM2Ring Is it night at your place already? Duh. Why is Australia SO FAR EAST?!

Anonymous

@PM2Ring Nice!

PM 2Ring

in Python on Stack Overflow Chat, Feb 5 '18 at 6:57, by Code-Apprentice

It cannot install on Samsung devices with Bixby because of a permissions conflict

@Blue In 40 minutes it'll be Saturday morning. :)

John Rennie

@PM2Ring I have to confess that there is a legacy site I manage that has all sorts of SQL injection vulnerabilities. But it's internal only so the big bad wolves don't have access to it. It's so large that the thought of going through all that code and removing all the vulnerabilities is appalling.

PM 2Ring

12:23

@JohnRennie That's understandable.

John Rennie

@PM2Ring somehow I manage to live with the guilt :-)

(Any hackers out there, please do not take this as an invitation :-)

PM 2Ring

OTOH, we get answerers who try to defend their vulnerable code by saying it doesn't matter because the OP is only using it internally. They don't care that future readers may use it without realising that it's vulnerable.

John Rennie

True ...

PM 2Ring

12:40

On the bright side, it means there's a big demand for digital security experts & penetration testers. ;)

Mithrandir24601

12:52

@PM2Ring That's simultaneously funny and sad

PM 2Ring

13:05

If it were some little obscure fly-by-night company, it'd be an unfortunate blunder. But for a major player like Samsung to do it is outrageous, IMHO.

I don't know how to answer OPs who talk about pure energy. What's impure about a lump of matter? On Earth, you aren't likely to see a more concentrated form of energy than a chunk of dense metal. Ok, it's not pure gauge bosons, but so what?

user351417

13:23

@EmilioPisanty Thanks for the recommendation! Ignition! is quite interesting. I never realized that popsci would contain interesting characters :P

Emilio Pisanty

@Chair no worries =)

user351417

Why do you put = signs in faces? It gives one the impression of a really crazed face... :) is so normal and squished.

Emilio Pisanty

: ) looks weird in the typing box on my device

or do you do :)?

user351417

Ah. Cool. I never realized that these things look that different on different devices. At lease SE doesn't autocorrect things to intimidating faces.

Emilio Pisanty

goodness

user351417

13:27

I don't put a space... :)

Emilio Pisanty

no, that's too much trouble

user351417

What's too much trouble?

Emilio Pisanty

backticks

user351417

No, that was just to show the spacing in a fixed-width font. Obviously I don't use backticks usually!

Emilio Pisanty

I mean

it's a pretty minor thing, no?

user351417

13:29

Yeah, I was just curious why you use the =s. See ya!

user351417

One studies occasionally

PM 2Ring

You also need to read Max Gergel's Excuse Me Sir, Would You Like to Buy a Kilo of Isopropyl Bromide? It's hillarious. And a little scary to read about the blasé attitude to safety and environmental protection they had back then.

user351417

That name has me giggling already

user351417

When will SE start using normal, meaningful charts?

user351417

13:31

(from stackoverflow.blog/2019/02/07/…)

PM 2Ring

Here's a sneak preview, which includes a link to the whole PDF. You don't need to be a chemist to enjoy Gergel's memoir, but a bit of chem knowledge helps. blogs.sciencemag.org/pipeline/archives/2010/05/27/…

user351417

An answer here was deleted by the author a moment ago. Looks like they were struggling with the mathjax.

user351417

Any ideas about what to do with it?

user351417

It wasn't a great answer anyways though...

user351417

(Looking at the deleted version, it seems downright unhelpful)

user351417

13:46

But it's still a shame that they chose to take it down within a couple of seconds of it having been posted. Like they made at least 3-4 edits over a moment before deleting it.

PM 2Ring

@Chair They might have decided to delete it while they're repairing it.

Or realized it was not worth trying to fix it. :) I've done that once or twice... It's amazing the flashes of insight you can have moments after posting, even when you've triple checked everything before hitting Submit. :)

Abcd

14:19

@Blue Do you know any super tricks for tree traversal?

Anonymous

@Chair :=) It's the nose.

Emilio Pisanty

15:04

@PM2Ring "2 Used from $250.00"

ugh

@Chair I've fixed the mathjax for them in case that's what was stopping them.

though of course if it were undeleted right now, it would go straight to the Not An Answer deletion queue

@Chair how do you have access to that?

user351417

15:57

@EmilioPisanty I was looking at the post while it was being edited (i.e. I clicked "an edit has been made to this post. refresh something-something" a couple of times), and then it suddenly got greyed out with a red banner saying "this post has been deleted". So that greyed-out version was still faintly visible; that's what I was talking about. It disappeared when I refreshed the page. Anyways, it's a pretty lame answer (or even, as you suggested, NAA), so it's not a huge loss.

vzn

@Chair like your priorities/ energy/ initiative on this but would like to see the right questions asked to achieve them. "driven away" interesting choice of words. one might ask what is it that drives away chat users? does that happen? btw KK who you had a long exchange with in meta used to be a regular. and one wonders why he left. etc... some ppl are "turned off" by interactions in here and leave but lets face it its a natural cycle for 1-time regulars to fade away over time...

user351417

@vzn No, I don't think he was put off by chat (if you're talking about Kyle Kanos as KK). He mentioned in a comment under Blue's post that he has other important things which take up the time.

user351417

He even mentions it in his about-me: he's not very active any more.

vzn

@Chair on reading the meta posts on this, think they are well written but have this recurring feeling of what problem is this trying to solve and there seems to be some assumptions or misidentifications about what the problem(s) are...

user351417

@PM2Ring I wouldn't think that they were deleting it because they thought it's not a helpful answer. Considering that the edits which I could see were minute mathjax fixes, I think that was the issue. Anyways, if Emilio's edited that, they can try undeleting it with a flag or something and either a mod'll suggest that it's NAA, or it'll go through the queues... I guess there's not much more to say about that topic.

user351417

16:04

@vzn I'm perfectly clear about the fact that this isn't going to play a huge role in getting more people to join chat. I've mentioned that before. The lack of participation here is certainly a problem we want to solve, but this meta post is not expected to be a way to motivate people to join. I've mentioned this before, but it's generally to make it easier for new users once they find their way here.

vzn

@Chair right away this phrase lack of participation in chat is somewhat problematic. there are subjective feelings related to ppl leaving but the overall usage/ activity is probably not a lot different. do like your ref to/ interest in community but its a very slippery concept in cyberspace/ SE. was it you that was thinking of making a chat ad? think that would go some ways toward promotion... its not hard...

vzn

16:18

@AvnishKabaj more trouble in paradise — Amazon’s Retreat on New York City Headquarters Followed Unexpected Backlash nytimes.com/2019/02/14/nyregion/amazon-hq2-queens.html

user351417

16:43

@vzn If you have any ideas for the design and slogan, please share them with us.

John Rennie

While the room is quiet let me post my latest culinary masterpiece. This time I have surpassed even myself. Ladies and gentlemen, fellow gastronauts, I give you:

The bacon pizza!

And for dessert:

Profiteroles!

enumaris

nice :D

John Rennie

I thought so :-)

But ... I feel kind of full now ... :-)

vzn

A Glazed Donut-Bacon-Egg Sandwich Isn't as Bad for You as You Might Think theatlantic.com/national/archive/2013/04/…

enumaris

17:05

dang, the head of the ICN is not as much of a dreamer as I had hoped

vzn

@Chair have some experience with this. have seen an ad with striking image outperform 2-1 something else more utilitarian in clicks (not surprisingly). therefore suggest any striking physics images, of which there are many, (am thinking off top of head of eg heatmap images of atom corrals or lasers etc) with very high-contrast easy-to-read text on top of it, the slogan is not so important, but sell the sizzle, not the steak :)

enumaris

I hope the new head of engineering is really good

vzn

@enumaris ICN?

ACuriousMind

17:36

@JohnRennie I think I got a little closer to a heart attack just looking at that ;)

3

John Rennie

@ACuriousMind :-) It's not as unhealthy as you might think. I didn't use any extra fat to fry the bacon, I fried it in it's own fat, and pizza dough doesn't have many more calories than the same weight of ordinary bread.

Avnish Kabaj

18:05

@vzn Oh yes

One of the states was offering $11B or something

Oh wait I got that wrong

$0 tax on $11B

@JohnRennie Needs moar cheeze

Honestly I don't like authentic Italian pizza

It's the American pizza I <3

vzn

@Avnish the amazon thing is (american) history being made before our eyes... remember when amazon was just a gleam in Bezos eye... so are you studying physics at a university?

Avnish Kabaj

@vzn Nope

12th grade

In the jee rat race

vzn

@AvnishKabaj yes have heard a lot about JEE on here, my sympathies. do you have a future major in mind?

Avnish Kabaj

@vzn CS > Electrical > Mechanical > Engineering Physics

vzn

@AvnishKabaj good idea(s), STEM is the (past/present+) future, cant go wrong there :)

Avnish Kabaj

18:14

Heh heh

Thanks :)

vzn

@AvnishKabaj yw! lol its really an egotistical praise :P

Avnish Kabaj

@vzn Oh boy

I just had a look at your profile

I had the impression you were a physics undergrad

vzn

@AvnishKabaj enjoy physics a lot but its more a dalliance/ avocation for me... there are some neat ways its coalescing with CS eg QC etc

Captain Bohemian

In December I visited my undergraduate school, having a lot of feeling.

that's an era when I could explore whatever I like without worrying about practical affair.

vzn

18:36

your recent musings reminded me of a quote, looked it up for you.

> I look at being a capitalist businessperson like riding a bike - if I go too slowly, I'll fall over. Or it's kind of like a shark: if I stop swimming, I'll just die. —Andrew Mason brainyquote.com/quotes/andrew_mason_449338

Jake Rose

18:52

Howdy everybody

@AvnishKabaj why not straight physics?

vzn

@JakeRose hey birthplace of the beatles! ... so whats your gf like?

Beta Decay

19:24

What do the square brackets mean?

thermomagnetic condensed boson

20:07

does a charged spinning sphere produce a current? I would tend to guess not, because drho/dt =0 despite that all the charges are in motion

am i correct?

so from an electrodynamics point of view, it makes no difference whether the sphere rotates on itself or not (assuming homogeneous charge density)

ACuriousMind

@thermomagneticcondensedboson By the same argument, no closed circuit produces a current :P

Anonymous

20:24

@DavidZ Re: (5) I'd not encourage asking mods for private chat rooms - definitely not before flagging, at least.. Why exactly? The custom mod flag has a rather small character limit and is often not sufficient to explain the context of the "worrying pattern". Also, I think it's better to solve issues at a local level before escalating them to the mods all over the network.

thermomagnetic condensed boson

true @ACuriousMind I am confused

in steady state, drho/dt = 0 or not?

rho is the charge distribution

ACuriousMind

@thermomagneticcondensedboson Current is not the time derivative of charge density.

thermomagnetic condensed boson

the divergence of the current density is

plus or minus a sign

ACuriousMind

Just like a liquid current is not the time derivative of the liquid's density.

thermomagnetic condensed boson

from the continuitiy eq drho/dt + div J = 0. In steady-state (this means current can be nonzero), I expect drho/dt not to change

is that correct?

err. i mean drho/dt = 0

(like I wrote above)

ACuriousMind

20:30

Yes, the divergence of current is zero for spinning charged sphere

thermomagnetic condensed boson

I see... thank you

ACuriousMind

Which makes sense - the flow lines of the current are closed circles, and "no divergence" means no sources or sinks for these flow lines.

thermomagnetic condensed boson

I think the Bridgman effect is proportional to div J. so in steady state, this effect vanishes

man that's so confusing . i read in several sources that the bridgman effect is the internal peltier effect but in a paper it is claimed that there's a distintion

one arises in anisotropic materials, the other in nonhomogeneous materials

and in anisotropic nonhomogenous materials, there are both effects (as well as a bunch of other effects)

ACuriousMind

As I have no idea what the Brigman effect is, I can't help with that :P

Anonymous

@Abcd No.

Anonymous

20:41

I'm not even sure what you mean by "super tricks" there. :P

Anonymous

I had developed some graphical "tricks" for pre-order, in-order, post-order traversal, for quickly writing the orders. But I think you can find them yourself from the pictures given in your textbook.

Anonymous

Say, pre-order traversal is like this. Just follow the dotted curve. You'll get a sense of it.

Anonymous

Same goes for the other traversals.

ACuriousMind

Uh...do they actually make you write down traversal orders by hand?

That seems...pointless

Joshua Lin

21:02

sometimes it be like that

Sir Cumference

22:32

@AvnishKabaj lol mathjax

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