The h Bar

AccidentalFourierTransform

6:04 PM

fellas

do we have any policy about mild curse words?

Danu

In chat or on main?

AccidentalFourierTransform

chat

Danu

They're fine

AccidentalFourierTransform

is darn ok? can we use the q-word?

DHMO

in Mathematics, 3 mins ago, by DHMO

@Secret Start with $\Bbb N$. Produce an algorithm to remove countably many numbers, countably many times, and end up with the empty set.

Just in case anyone is interested

Danu

6:06 PM

What's the q-word?

I'm gonna go ahead and say no

ACuriousMind

@AccidentalFourierTransform Eh, there's no policy against curse words as such, but there is one against being rude.

anonymous

@Danu Unless they are used as abuse I guess....

Danu

@anonymous That's right.

heather

the q word doesn't seem mild.

AccidentalFourierTransform

ok then :-(

heather

6:07 PM

darn, on the other hand, is very mild.

Danu

@AccidentalFourierTransform Was this some kind of joke?

heather

even a child like me can get off with saying it =P

ACuriousMind

Dec 28 '16 at 16:16, by ACuriousMind

Like all cats, it seems the Fourier transformed version is also a bit of a troll ;)

AccidentalFourierTransform

^

anonymous

@heather Mildness is extremely relative. Some people find the f-word to be very mild. So I think the best policy is to overlook curse words unless used as abuse aimed at something or someone.

heather

6:09 PM

@anonymous fair enough.

AccidentalFourierTransform

oh the irony!

welcome @FuckSONGS

anonymous

lol

XD

AccidentalFourierTransform

Hi @JaimeGallego, I see you're from Madrid :-)

Im from Madrid too

are you in college?

Jaime Gallego

Not yet

AccidentalFourierTransform

yeah in your picture you look kinda young but I wasnt sure

and you know what you are going to study?

are you into physics?

Jaime Gallego

6:12 PM

That's from 2013 or something :D

Yup

DHMO

es espana se usa el verbo "oir"? @JaimeGallego @AccidentalFourierTransform

AccidentalFourierTransform

@DHMO yep, "hear"

Jaime Gallego

Hi again @DHMO. Yes it does

AccidentalFourierTransform

@JaimeGallego nice! and which uni youre going to choose? UAM? UCM?

DHMO

@AccidentalFourierTransform mi amiga que vino a argentina me dice que no se usa este verbo en argentina

AccidentalFourierTransform

6:14 PM

@DHMO we use it a lot in Spain, but now that you mention it, people in South America use "escuchar" instead of "oir"

"escuchar"= to listen, "oir"=to hear

DHMO

@AccidentalFourierTransform si, yo lo se

Jaime Gallego

@AccidentalFourierTransform Probably UCM, though UAM is a lot closer. That's not my Plan A though, I'm planning to study in the States.

heather

@DHMO without google translate and with one semester of spanish: "my friend who [something] to argentine said [something] argentina"

Jaime Gallego

@heather "My (female) friend that came over to Argentina tells me that this verb isn't used in Argentina"

AccidentalFourierTransform

@JaimeGallego cool good luck with that!

DHMO

6:16 PM

@AccidentalFourierTransform se usa en espana el verbo escuchar tambien?

heather

@JaimeGallego ah, okay, thank you.

DanielSank

@dbassett sure. I'll be in my office soon and might be able to chat.

DHMO

@JaimeGallego o dios, use el verbo incorrecto. quise decir "fue" no "vino"

DanielSank

I look at online chat as an asynchronous communication protocol...

Jaime Gallego

@DHMO Sí. But it means two different things. Oír -> hear, escuchar -> listen

AccidentalFourierTransform

6:17 PM

@JaimeGallego I studied physics at the UAM, and Ive been told that it is slightly better than the UCM, though both are kinda good. If you can go to the states, that's obviously the best option

@DHMO yes, I use both of them

though "oir" is more common IMO

ACuriousMind

@AccidentalFourierTransform It is?

DHMO

@JaimeGallego entonces en espana los dos verbos se usan para decir cosas diferentes y en el sud de america solo escuchar se usa

ACuriousMind

I'm not convinced "the states" are "obviously" the better option without a lot more details :P

DHMO

@AccidentalFourierTransform ah, gracias

heather

@ACuriousMind usa is totally the better option (not biased at all =)

AccidentalFourierTransform

6:19 PM

@ACuriousMind better than anything in Spain at least

@DHMO np :-)

heather

the temptation to speak in spanish and make a fool of myself is strong =)

AccidentalFourierTransform

@heather well you have me here trying to speak English

my English is far from perfect but its fun to speak other languages

BTW if you want to practice your listening, a friend of mine has a youtube channel which is kinda popular here in Spain

he makes videos about physics

in Spanish

youtube.com/user/QuantumFracture

DHMO

@heather no puedes mejorar tu espanol si no quieres hablar en espanol

Jaime Gallego

@ACuriousMind The colleges I plan to apply are certainly better. It's a long shot, but I will be sending applications to MIT, Caltech and others. Fingers crossed.

Sir Cumference

Howdy

heather

6:22 PM

@AccidentalFourierTransform to be absolutely honest, you seem pretty good at English

DHMO

@AccidentalFourierTransform y "educatina" habla espanol americano

Sir Cumference

@DHMO ¿Lo hablas?

DHMO

@SirCumference no, "educatina" es el nombre de un canal

AccidentalFourierTransform

@heather ah, I wish

Sir Cumference

@DHMO Ah XD

Estoy aprendiendo español. No estoy perfecto pero puedo tratar de usarlo.

Me gusta aprender idiomas. :)

DHMO

6:25 PM

@SirCumference si quisiste decir "hablas espanol americano?", lo estoy aprendiendo

DanielSank

@heather do it. I'll join.

heather

soy terrible en espanol

DHMO

@SirCumference eso es una actitud buena

heather

@DanielSank muy bien =)

ACuriousMind

A bit of Spanish (or other languages) is fine, but please keep the main conversation in English

Sir Cumference

6:25 PM

@DHMO ¿Es necesario? Español es similar en todos los países

DanielSank

@ACuriousMind is that actually a rule?

DHMO

@SirCumference estoy aprendiendo espanol espana tambien, entonces...

ACuriousMind

34

A: What languages are we allowed to speak in SE chat rooms?

The short answer is: whatever language the other folks present in the room are comfortable speaking. All else being equal, if you jump into a room and start posting stuff that isn't understandable to the majority of the users there, you're probably going to get some pushback. And as a practical...

Sir Cumference

@DHMO ¿Estás aprendiendolo en tú colegio/universidad?

AccidentalFourierTransform

@ACuriousMind halt die Klappe

DHMO

6:27 PM

@SirCumference no, lo estoy aprendiendo solo por mi misma

Sir Cumference

@DHMO Yo también :D

@ACuriousMind Oh come now, it's good to meet people who speak or want to learn the same languages as you

DanielSank

Well, I guess since my phone wants to autocorrect everything I type in Spanish I'll have to forget about it for now.

DHMO

@ACuriousMind "Majority" ist ein ziemlich vages Konzept ...

Sir Cumference

Not to mention, there's no inherent reason anyone needs to pry into what we're saying

DanielSank

@DHMO LOL

Sir Cumference

6:28 PM

@DHMO You're learning German too?

Jeez

AccidentalFourierTransform

The Simpsons couch gag [YOU'RE NEXT]

►

BEST. VIDEO. EVER.

DanielSank

@SirCumference true, but at some point such conversations should move to another room.

@SirCumference could be Google translate...

ACuriousMind

Can't reiterate the point about not using a different language to carry on a private conversation in plain view. If you do that, you'll likely get flagged into a chat suspension. Remember, intentionally excluding everyone else in a room from the conversation you're having with another is very rude and you should not do it (since this keeps coming up). — Tim Post ♦ Jan 20 '14 at 12:19

Sir Cumference

@DanielSank It's not that deep of a conversation, we're just saying "hello", "how did you learn spanish", etc

It's literally just the surface of a conversation

Physics Meta

1

Q: Should we have an "Answer Later" section?

Several times when writing long and detailed answers, I am unable to find time to finish it all in one go. I know draft of unfinished answers are saved and if I visit the question again, I can continue working on it. However, I think there should be a separate section where all unfinished drafts ...

feature-request

Sir Cumference

6:30 PM

@ACuriousMind If people actually speak spanish and care to join a conversation about it, they can. Otherwise, it shouldn't be relevant to them.

DHMO

@SirCumference I know some basic German words and grammars but the sentence was too hard for me so I used Google translate

ACuriousMind

@SirCumference ...if you're holding your Spanish conversation in the middle of the main chat room of an English speaking site, it kinda becomes relevant to them.

Sir Cumference

@ACuriousMind Does it? Honest question, not to be rude — what makes you think anyone cares about a conversation not addressed to them?

Jaime Gallego

@ACuriousMind I have to agree here. It's the main Physics chat after all.

Bernardo Meurer

@heather What about Ackermann?

Sir Cumference

6:32 PM

If two people are using a different language, it's clearly not something that non-speakers should consider relevant

A group conversation should use the language of the chat. Something not important to the majority of people need not be readable to everyone — there's really no point.

ACuriousMind

@SirCumference What if you're making fun of someone who doesn't speak the language? What if you're talking about a topic I would also be very interested in discussing? Conversations in this chat should, in principle, be free for everyone to join, since it is the site's main chat. If you have to have a private conversation with someone, have it somewhere else.

heather

@BernardoMeurer recursive...

ACuriousMind

Another aspect: How are moderators supposed to moderate conversations they don't understand? I am reasonably sure that you, personally are not saying much moderation-worthy right now, but in general, enforcing English in chat is enforcing that chat can be moderated.

heather

@ACuriousMind i'd honestly have to disagree - that's like me asking Bernardo about a linux error I'm having and other people who have turned to the dark side and use windows asking us to get out because we use a different OS.

Sir Cumference

@ACuriousMind Making fun of a person is breaking a rule in itself, that should be punishable severely if someone realizes it. Using a language is not inherently vindictive.

heather

6:36 PM

@ACuriousMind google translate. ::shrugs::

Sir Cumference

^

There's no insult google translate shouldn't be able to handle.

heather

@SirCumference lol

Sir Cumference

I have to go now, later.

heather

have a good day @SirCumference

AccidentalFourierTransform

"This user has been temporarily suspended by a moderator and cannot chat for 3 days."

Jaime Gallego

6:37 PM

@SirCumference Bye!

AccidentalFourierTransform

THE COUNTDOWN BEGINS

anonymous

@SirCumference Google translate can't understand Hindi/Sanskrit/Arabic insults XD

ACuriousMind

@heather cc @SirCumference So, the existence of a tool that circumvents language barriers is a reason for erecting such a barrier?

DHMO

Mar 18 '15 at 16:09, by ACuriousMind

Wie soll das denn gehen?

Bernardo Meurer

@heather I wrote it in an iterative manner :)

MUCH FASTER

heather

6:40 PM

@ACuriousMind no, you were asking how you could moderate things in other languages that moderators don't necessarily understand. google translate is a solution to that problem.

Bernardo Meurer

heather

also, allowing people to talk in other languages isn't erecting a barrier, but rather removing one, i think.

2

Bernardo Meurer

MY BABY IS HERE

AccidentalFourierTransform

I got $A(99,99)$ problems and arbitrary-precision arithmetic aint one

anonymous

@heather Google translate isn't good enough to translate every language...

Bernardo Meurer

6:41 PM

@AccidentalFourierTransform You say that just as I post the book I got to learn more arbitrary precision arithmetic algos

anonymous

And it is time consuming too

ACuriousMind

@heather You have to be able to speak English to participate on the main SE sites anyway.

DHMO

@ACuriousMind which rule states that?

AccidentalFourierTransform

@BernardoMeurer i always knew you and I had some sort of mystic connection

ACuriousMind

@DHMO ...non-English posts are (except for the language versions of SO) not allowed on any site.

heather

6:43 PM

@ACuriousMind yes, so?

DHMO

@ACuriousMind I see. The same does not apply in chatrooms...

heather

why does that ban other languages in chat?

DHMO

g-block elements

One does not simply speak English 24/7. (This is the german Fo...

Bernardo Meurer

@AccidentalFourierTransform It's called love

AccidentalFourierTransform

we need to talk

we should see other people

ACuriousMind

6:44 PM

@heather That was supposed to be an argument for why allowing people to talk in other languages doesn't remove a barrier in this case - they are expected to be able to speak English anyway to participate

AccidentalFourierTransform

its not you, its me

anonymous

@DHMO In that case there is a German mod who can understand what's being written.

heather

@ACuriousMind oh, i see. well my response to that would be there are some users whose first language isn't english, and they might be able to get a better answer if explained in another language.

DHMO

@anonymous oh, so we can only talk in languages that the mod can understand

in this case... I am sure that the mod hier kann Deutsch verstehen

ACuriousMind

@DHMO And do you notice the difference between a dedicated chat room for that language (on a site where one of the mods is a German speaker no less) and starting to speak Spanish in the main chat room of a site when you have no idea how many people understand it?

anonymous

6:46 PM

@heather Just create another chat room for the special purpose then instead of the main chat.. I believe ACM is right here

Bernardo Meurer

@AccidentalFourierTransform But, honey, I'm blind

DHMO

@ACuriousMind when I started speaking Spanish, there were only two people talking, and they are both from Madrid

ACuriousMind

@DHMO Two people talking doesn't mean two people listening. There are more users in the room and it's not uncommon for them to lurk and wait for something that catches their interest. The chat room is more than "the people currently talking" or even "the people regularly talking".

DHMO

@ACuriousMind point taken

DanielSank

@ACuriousMind Hmm, let's find out: dmkee is secretly a robot monkey.

::waits::

ACuriousMind

6:52 PM

@DanielSank C'mon now, we all know he's your sock ;)

DanielSank

SHHHH!

Danu

7:03 PM

> citation numbers :D

Bernardo Meurer

I got new socks today

Danu

I'm pretty sure it's mostly a matter of connections. Due to some historical events the center of (HE)P is there and therefore it's easier to get well-known/highly cited by being there and associating with the big guys.

AccidentalFourierTransform

@BernardoMeurer you can see in the reflection in your laptop that you were naked when you took that picture

Bernardo Meurer

@AccidentalFourierTransform Actually, one of the few moments I'm not half naked while at home

AccidentalFourierTransform

so u naked right now?

Let me get changed into something more comfortable

Bernardo Meurer

7:07 PM

Nope, it's an exception

AccidentalFourierTransform

oh snap

Bernardo Meurer

I have jeans and boots and a sweater on :P

AccidentalFourierTransform

this was becoming sexy

now youve killed the mood

Bernardo Meurer

I have that habit

heather

-1

Q: nematic order numerical calculation

How can I calculate the nematic order parameter as function of temperature using monte carlo either with mathematica or with matlab? Is there any code available?

condensed-matter

^gimme teh codez

Bernardo Meurer

7:16 PM

@heather Yeah

AccidentalFourierTransform

So I've been working on this little project of mine

its called "quantum mechanics under the Riemann hypothesis"

you basically solve standard QM Hamiltonians using the Riemann hypothesis

its very interesting and its actually rather simple

you just assume the RH, and then proceed as usual, without using the RH for anything

you assume it holds, but then never mention it again

heather

@BernardoMeurer Oh, the sarcastic comments I could write...if not for that gosh darned "be nice" policy.

AccidentalFourierTransform

For example, let us diagonalise $H=\frac12 P^2+\frac12 X^2-\frac12$. First, assume the RH

Next, introduce the ladder operators. Finally, use $[H,a]=-a$.

Congratulations! you've shown that, under the RM, the eigenvalues of $H$ are $0,1,2,\cdots$.

Well, you just do this will the rest of solvable Hamiltonians

so in the end you have shown that the RH implies the typical results of QM. Neat, right?

Secret

extremely weird result in cardinals (to be checked by maths guys): We can take real number of things out of a countable set and it will still be countable:

in Set theory, 27 mins ago, by Secret

in Mathematics, 9 mins ago, by Secret

Consider the dedekind cut 0. This gives the subset $\mathbb{Q_{\leq 0}}$. Therefore the rationals are being partitioned by 0 into the nonpositves and the positives. Similarly for the naturals, there is also a partition of even and odd integers.

Since a bijection exists between rationals and naturals, dedekind 0 cut maps to $2\mathbb{N}$

Now consider some real number $s<0$. This gives a dedekind cut of $\mathbb{Q_{\leq 0}}-X$ where $X$ is the set of all rationals between s and 0, which is countable.

ACuriousMind

@AccidentalFourierTransform uhhhhhhhhh

Bernardo Meurer

7:19 PM

@heather I'm never nice

Sir Cumference

@ACuriousMind That's simply a solution for the problem you mentioned. There are certainly better reasons for it than against it. You speak German, so you probably know, but being able to speak in a shared language with someone else is an amazing and fun way to get to know them.

AccidentalFourierTransform

@ACuriousMind c'mon, it is neat ;-)

Danu

@AccidentalFourierTransform That's pretty lame.

Bernardo Meurer

How the hell with the Riemann Hypothesis imply a physical result such as QM?

ACuriousMind

@AccidentalFourierTransform Do you know there's actually some people working on connections between the RH and QM? I recall someone (Connes?) wanting to recast the zeroes of the zeta function as the spectrum of a Hamiltonian; then the RH becomes equivalent to its self-adjointness.

Danu

7:21 PM

You're just saying "vacuous truths are cool"

but they really aren't interesting.

Sir Cumference

Being "excluded" is a nonsense thing to take offense to, especially when it's not directed to that person.

Danu

@BernardoMeurer Just look at the truth table of implication.

Bernardo Meurer

@Danu Hum?

Danu

@BernardoMeurer Look at what happens when the conclusion is known to be true.

Sir Cumference

@ACuriousMind We're not talking about making this a language center. But interfering simply because people want to speak in a different language, under the belief that other people necessarily care about the conversation, is not needed.

AccidentalFourierTransform

7:23 PM

@ACuriousMind yeah I know, I was reading about that a couple of days ago

Bernardo Meurer

@Danu I'll just go back to computing $10^9!$ :P

Mike Miller

@ACuriousMind we're gossiping about you

AccidentalFourierTransform

it is actually very interesting

ACuriousMind

@MikeMiller oO

Jannik Pitt

Guys quick question: is Fermi's constant the same as the weak coupling constant? Both determine the strength of the weak interaction right? :D

AccidentalFourierTransform

7:29 PM

they are related

but they are not exactly the same thing

Bernardo Meurer

How large a factorial can I compute?

Anyone has a computer with 32GB RAM to help?

:P

AccidentalFourierTransform

@JannikPitt Fermi's constant is G_F

and the weak coupling constant is g_W

they are related through G_F=\sqrt{2}g_w^2/8m_W^2

where m_W is the W-boson mass

Jannik Pitt

okay awesome thank you!

AccidentalFourierTransform

np

Jannik Pitt

I like your name haha

very original

AccidentalFourierTransform

7:32 PM

well thanks, I chose it myself!

:-P

Physics Meta

0

Q: Is this a question for Physics or Engineering community?

I have a question about forces required to lift weights, and I need someone to look over my math. Should I ask this in Physics or Engineering community?

support

AccidentalFourierTransform

7

Q: Positive frequency solutions in a stationary spacetime

I'm studying the basics of QFT in curved spacetime, and for the simplest case of real scalar fields we can define the Klein-Gordon Hermitian form by $$ (f,g) = i \int_\Sigma \mathrm{d}^3x \sqrt{h} n^\mu ( \overline{f} \partial_\mu g - g \partial_\mu \overline{f}) $$ With $\Sigma$ a spatial hypers...

quantum-field-theory general-relativity qft-in-curved-spacetime

@ACuriousMind @Danu how come this didn't get any answer?

Im awful at diff. geom.

but the question seems (?) rather simple

or is it?

any of you know the answer? the question is still in its grace period, if you post something now you can get the bounty

you have an hour

ACuriousMind

7:55 PM

Ugh, QFT in curved space :P

AccidentalFourierTransform

well the question is simpler

the inner product $(f,g)$ on-shell is independent of $\Sigma$

therefore, it seems to me that one may take $n^\mu\propto k^\mu$, for $k$ the Killing field

acc. to OP this can only be done if the Manifold is static

but why?

cant you always take $n\propto k$? after all, you can choose the surface $\Sigma$ at will, right?

ACuriousMind

If you are in fact free to choose $\Sigma$, then you are right. The question is not particularly clear on how $\Sigma$ is chosen.

AccidentalFourierTransform

yes, if $f,g$ satisfy the KG eq. then $(f,g)$ is independent of $\Sigma$

ACuriousMind

@AccidentalFourierTransform perhaps OP is not aware of that fact? I think their problem is that, in a stationary but not static spacetime, the foliation into hypersurfaces induced by the notion of time given by the Killing vector has hypersurfaces where the Killing vector is not orthogonal

(where by "foliation induced by the notion of time" I mean the spatial slices you have in the coordinate system where the Killing vector is (1,0,0,0))

AccidentalFourierTransform

I guess I'll leave a comment

Danu

8:09 PM

Federer win Autralian Open 2017 (Titanic song)

►

I love it

Bernardo Meurer

8:20 PM

I HATE FONTS

also, texlive is a mess

Bernardo Meurer

8:50 PM

@DavidZ @alarge I've moved to Gnome on Xorg. Wayland has a debilitating bug happening to me where some Xwayland applications will lock all other windows and make them unclickable at random

heather

@BernardoMeurer and so we try to break mathjax again

Bernardo Meurer

@heather No more breaking mathjax

AccidentalFourierTransform

9:02 PM

heather

@AccidentalFourierTransform wow

AccidentalFourierTransform

wow indeed

@heather BTW

reddit.com/r/Showerthoughts/comments/5qoora/…

ACuriousMind

@AccidentalFourierTransform I thought starting the text with "physics" was a nice touch :P

AccidentalFourierTransform

@ACuriousMind and the tags... I dont know what to say

anonymous

@AccidentalFourierTransform Was that a new user ?

AccidentalFourierTransform

9:10 PM

@anonymous yes, member since today

anonymous

It was so funny that I forgot to laugh O:}

@ACuriousMind Me too...I felt that is was comprehension based question like in SATs and all :D

I read the whole post and then realized that I am a fool :P

heather

@AccidentalFourierTransform ouch

AccidentalFourierTransform

lol

Emilio Pisanty

Yo @DanielSank, you may be interested in this: github.com/episanty/TheYoungManTheStation

feedback welcome

Emilio Pisanty

10:46 PM

This is pretty interesting. The TeX.SE top users seem to have taken a pretty significant User Removed hit recently.

ACuriousMind

@EmilioPisanty Wow, I thought users with many votes usually had their votes transferred to community before deletion

anonymous

@EmilioPisanty How do you know that was a "User Removed" hit and not negative reputation gained due to downvoting by others?

Negative rep is usual on Stack Overflow also

see stackoverflow.com/…

ACuriousMind

11:05 PM

@anonymous Go to the reputation tabs of the individual users. Normally, you will find that most large losses are due to offered bounties, and that downvoting is insignificant (not even I downvote enough answers to get to significant rep losses in such a short time). On tex.SE, there's a "user removed" on each rep tab.

anonymous

@ACuriousMind Oh I see. Thanks. I didn't look at their activity tab earlier. However I do know some users who mainly downvote and hardly upvote on Math SE and Stack Overflow :P

ACuriousMind

Downvoting questions doesn't cost any reputation; only downvoting answers.

AccidentalFourierTransform

chaps at TeX.SE just like upvoting

DanielSank

@ACuriousMind I did not know that.

AccidentalFourierTransform

tex.stackexchange.com/users/3094/paulo-cereda?tab=topactivity

DanielSank

11:10 PM

@EmilioPisanty Feedback given.

ACuriousMind

@DanielSank Now you know ;) It wasn't like that from the beginning, there's an ancient meta.SE post about abolishing the cost to downvote questions to get users to actually downvote bad questions.

AccidentalFourierTransform

wheres that meta post?

I want to downvote it

cause, you know, its free

Emilio Pisanty

@anonymous uh... because it says that on the rep pages for the affected users?

@DanielSank yeah, both planned, this is in draft stage at the moment

anonymous

Anyone knows why the StackOverflow site is much smoother than the StackExchange sites ? Or is it only me?

@EmilioPisanty Yeah ACM told me :)

Emilio Pisanty

@anonymous what do you mean by 'smoother'?