The h Bar

Danu

5:00 PM

@0celo7 But you know I love you, deep down in my heart, don't you?

0celo7

@Danu no, I don't think you do

Danu

but it's true!

FenderLesPaul

@0celo7 And God only knows

what I'd be

without youuuu

0celo7

I'm not some battered woman

skull patrol

You're like the boy who cryed "Wolf!"

0celo7

5:01 PM

yeah I cry wolf when the wolf is right there doing wolf things

Danu

FenderLesPaul eloquently expressed my feelings towards you @0celo7

0celo7

only God knows that you'd be happy? hardly.

Danu

If you really feel like I dislike you and am trying to bully you or something, I sincerely apologize because that is definitely not what I meant to do.

I do like that you're always around here, keeping chat alive. I don't want you to leave.

skull patrol

The things the wolf is doing are not wolf-like :-)

0celo7

@Danu aww

Danu

5:02 PM

Anyways, I gotta run for dinner now

brb

0celo7

now I have to take down the dart board with your avatar on it

skull patrol

Later pal

You can use my avatar on your dart board, I won't mind ;-)

0celo7

@skullpatrol I already have another user in mind

ACuriousMind

<-This one

skull patrol

A ^bully?

A Curious Bully's Mind.

0celo7

5:11 PM

@ACuriousMind no, why would you think that

HDE 226868

@0celo7 Am I on the chopping block?

0celo7

that means you know you've done something to deserve that, which means you know you're guilty of something

skull patrol

The mind of a bully is not a curious thing

ACuriousMind

30 mins ago, by ACuriousMind

lol, his "userbase" are like four guys from this chat

0celo7

@ACuriousMind I forgot that already

time flies in Tamriel

HDE 226868

5:12 PM

@0celo7 I don't know; Duffield accused me of doing quite a lot while I think it was clear that I wasn't bullying him. Perceptions differ.

0celo7

@HDE226868 you've been considered

HDE 226868

@0celo7 For any reason in particular?

0celo7

@HDE226868 everyone has been considered

FenderLesPaul

no one wants me on a dartboard :(

skull patrol

Define bullying

FenderLesPaul

5:13 PM

Why am I so loved T_T

0celo7

@FenderLesPaul because you know something about GR

ACuriousMind

@FenderLesPaul I'm indifferent towards you :P

0celo7

that's ACM's biggest flaw (well, second, if you consider the whole BDSM club thing)

FenderLesPaul

@0celo7 I'll take it!

HDE 226868

@0celo7 Ah, then I feel better.

0celo7

5:14 PM

@ACuriousMind fight

you can't be indifferent

skull patrol

Why not?

FenderLesPaul

@ACuriousMind yay!

0celo7

@skullpatrol it's a theorem

skull patrol

Why didn't you go to Columbia @FenderLesPaul?

FenderLesPaul

@skullpatrol I wanted to get out of nyc after having lived there for 18 years

didn't get too far away though

so my parents still threaten me with visits

skull patrol

5:19 PM

I see.

FenderLesPaul

Also I didn't want to deal with their gen-ed program

it's really strict and expansive and I don't want to be bothered with those useless classes

the only interested gen-ed classes I've taken are history of rock and linguistics

interesting*

Kyle Kanos

@FenderLesPaul Press Up arrow to edit your last message (only works for ~2 minutes)

skull patrol

Is the Bronx school of science still #1

FenderLesPaul

@KyleKanos oh cool thanks, didn't know that

@skullpatrol no I don't think they've been #1 for a long while

certainly not when I was there

0celo7

my HS was in the top 600...does that get me anything?

skull patrol

5:26 PM

A trip to the LoC ;-)

FenderLesPaul

sadly not a lot of people from my HS go into physics anymore it would seem

there were only like 2 in my year, out of like 500 kids

myself included

0celo7

I don't know anyone from my school who went into a pure discipline

most are doing CS or some form of engineering

FenderLesPaul

yeah CS is really popular

skull patrol

Bronx still holds the record for Nobel prize winners in physics right? @FenderLesPaul

FenderLesPaul

yeah

7 I believe

the 8th one was chemistry boo

0celo7

5:30 PM

what does one do at such a high school?

spacetime topology as an elective?

skull patrol

:-)

FenderLesPaul

dude that would've been so sweet if it had existed

a lot of people just took topology and related classes at Columbia

the people I knew anyways

0celo7

>just

My math teachers didn't know what line integrals were

FenderLesPaul

Does anyone really know what line integrals are?

skull patrol

-_-

FenderLesPaul

5:32 PM

askin the real questions

0celo7

@FenderLesPaul ::raises hand::

is this a trick question?

FenderLesPaul

@0celo7 maybe; you have to believe in yourself

life is fleeting

no one knows what it's like

to be the bad maaan

skull patrol

except the bad maan

0celo7

I need to start getting my shit together for the move

skull patrol

Bad to the bone.

0celo7

5:34 PM

holy balls I have a lot of books

I can probably leave AP review books

I'll take Chem just in case I need some Chem

I need to get Freakonomics 2

skull patrol

Wb @Danu :-)

Danu

Hi

skull patrol

How was the home cooking?

Danu

5:58 PM

Good, good.

Slereah

Back from the dentist

My face is extremely numb!

skull patrol

Cavities?

Slereah

indeed

Got an inlay put in

The numbness is inconvenient but not as much as the pain when it will go awa!

skull patrol

6:10 PM

in English Language & Usage, 13 mins ago, by Cerberus

Windows 10 takes all your data, including calendar appointments, contacts, browser history, etc. etc. and sends them to Microsoft every day: https://www.techdirt.com/articles/20150802/07341031825/microsoft-launches-specia‌l-scott-mcnealy-edition-windows.shtml

Danu

@skullpatrol It's not that hard to disable.

(if you're smart enough to go for "customize settings" during the installation)

skull patrol

We have zero privacy anyway @Danu

Even the stuff we say in this chat is Google searchable.

Slereah

6:25 PM

So anyway

Danu

@skullpatrol I don't go to the internet for my privacy :P

Slereah

What is the deep meaning of $\langle0|phi(x)phi(y)|0\rangle$

I know it's supposed to be "the probability of a particle going from x to y"

But is it an accurate assessment, or just a simplification

0celo7

I think you need a time ordering thing

Slereah

Sure, but I mean more the semantic behind it than the math

Danu

It's just the propagator. The Green's function.

ACuriousMind

6:27 PM

@0celo7 Nope, but there is a ${}^\dagger$ missing.

Slereah

I know

But I mean the physics behind it

0celo7

Then what's the thing with the time ordering?

ACuriousMind

@0celo7 Feynman propagator

Slereah

Also what would $\langle k|phi(x)phi(y)|k\rangle$ mean, in this case

0celo7

@ACuriousMind Ah yes

Slereah

6:28 PM

Or with any state

ACuriousMind

@Slereah If you think of $\phi(x)$ as creating a state localized at $x$, this is just a way of writing $\langle x \vert y \rangle$ (but you shouldn't write the latter for various reasons).

I'm not sure what you want.

Danu

@Slereah The same thing happening in a different "background state" (a 1-particle state in this case)

Slereah

Oh

0celo7

I should make a leaning tower of books

@HDE226868 A small planet somwhere in the vicinity of Betelgeuse...you're fucked. ::prints out avatar::

Slereah

I believe you mean

Beetlejuice

skull patrol

6:46 PM

Juice, geuse no biggie

Same goes for Betel/beetle

FenderLesPaul

mroar

Huy

7:15 PM

@skullpatrol: Microsoft is just being straight for a change and most of these "security concerns" can be disabled when installing Windows 10. Other companies (e.g. google as you mentioned) do the exact same thing but don't always give you a choice to disable it.

Slereah

7:34 PM

Hm

I can't find my order of my two physics books

I ordered them at work, but I can't see it on my amazon

ah, there it is

It should be there by saturday apparently

NeuroFuzzy

7:46 PM

@0celo7 so my studying of Hawkings book turned into me studying a book on manifolds first. Prooobably a good idea. I think this book (Manifolds Tensors and Forms by Renteln) covers some of what you were saying was requisite from Nakahara.

FenderLesPaul

@Slereah do you have Prime?

0celo7

@NeuroFuzzy That books has a lot of stuff you won't need for HE.

On the other hand, it has a lot of stuff you do need...

NeuroFuzzy

What are you referring to specifically? I ignored most of the sequences of maps stuff.

@0celo7

Danu

@NeuroFuzzy Lee Lee Lee Lee Lee

Lee - Intro to Smooth Manifolds is more than excellent (imo)

FenderLesPaul

@Danu seconded

Danu

7:52 PM

It will go way beyond what you'll ever need for a physics book, but it's so nice.

FenderLesPaul

superb book

it's written so well

Danu

You can also skip a bunch of chapters

(e.g. Sard's theorem)

FenderLesPaul

His topological manifolds book is pretty cool too

Danu

Is it?

I didn't invest any time in reading it

The differentiability is what I care about :P

FenderLesPaul

Yeah a fair number of the problems are really fun

NeuroFuzzy

7:54 PM

Ooh and a section on lie groups

FenderLesPaul

very counter-intuitive stuff

He apparently has a 3rd book on Riemann manifolds but I've never looked at it

0celo7

@NeuroFuzzy That's setting you up for cohomology I think.

Danu

@FenderLesPaul It's very short.

My prof. was not impressed by it

0celo7

@NeuroFuzzy 4, 5 are things you should know, but not for HE. 7 is probably superfluous. HE uses bundles sparingly.

Appendix G seems interesting...

Danu

You don't really need the details from any of the chapters in Lee to read HE.

FenderLesPaul

7:58 PM

@Danu ah ok, that's too bad

0celo7

@Danu I wasn't referring to Lee.

Danu

@0celo7 Woops, sorry :)

0celo7

@Danu :)

Danu

What? You're acting weird again

(you're too easy to troll, man :P)

0celo7

@Danu You're the best kind of troll: I just end up confused and wondering how what you were doing was trolling

whatever

@NeuroFuzzy I agree with @Danu that you don't need Lee's smooth manifolds book for HE. HE's difficulty (imo ofc) comes from the insane number of theorems, lemmas and definitions that you usually won't be reminded of.

Danu

8:03 PM

@0celo7 Sadly, this is true for most mathematically-oriented books.

0celo7

@NeuroFuzzy Of course, you will need to know some random geometry facts that are not derived, such as the Riemann tensor for a maximally symmetric space, the (maybe a, he might have multiple) Hodge theorem and the Poincare-Hopf theorem.

NeuroFuzzy

Ahh. Gotcha.

Danu

8:20 PM

@0celo7 Really? I hate when physicists do that: Require that you know the most high-level results, but of course nobody has to know how to get there :P

DanielSank

Why did you guys close this?
http://physics.stackexchange.com/questions/197711/colliding-objects-combine-energy-can-surpass-c#197711

Danu

@0celo7 Also I guess you didn't mean this Hodge theorem hehe ;)

A Challenger appears! @DanielSank

ACuriousMind

@DanielSank I had no idea what it was asking, and voted unclear what you're asking.

Danu

Also I'm stupid, nvm those comments

:D

I'm editing the question for clarity (and voted to reopen)

ACuriousMind

what is the question about the energy now, exactly?

In "Assuming that the batches actually front-collide (which is a long shot I know), isn't the resulting energy (not the "total speed") than a batch hitting a static object?" there seems to be an adjective missing

Danu

8:25 PM

larger

ACuriousMind

But...the LHC already collides protons with protons moving in the opposite direction?!

Danu

Yeah, it does. Lol.

ACuriousMind

We don't fire at static targets (except in that one side branch, IIRC) do we?

Danu

Dude, the newest one will be linear, I think!!!

DanielSank

@ACuriousMind It's perfectly clear to me...

Danu

8:27 PM

I was so confused about that, too... Why would we build a LINAC?

DanielSank

@ACuriousMind Yes, the grammar was terrible. I fixed it and then OP rolled back for some reason.

I fixed it again (and so did @Danu) . Hopefully it will stick.

Danu

Oh, cool, it's about the synchrotron radiation.

For heavy particles, it's better to have circular ones.

International Linear Collider

The International Linear Collider (ILC) is a proposed linear particle accelerator. It is planned to have a collision energy of 500 GeV initially, with the possibility for a later upgrade to 1000 GeV (1 TeV). The host country for the accelerator has not yet been chosen and proposed locations are Japan, Europe (CERN) and the USA (Fermilab). Japan is considered the most likely candidate, as the Japanese government is willing to contribute half of the costs, according to the coordinator of study for detectors at the ILC . Construction could begin in 2015 or 2016 and will not be completed before 2026...

0celo7

@Danu No the one that gives the necessary and sufficient condition for the Laplace equation to be solvable. Or something like that.

Danu

physicsworld.com/cws/article/news/2014/feb/06/…

Hahhahahahaha, guess who is in the comments saying that a successor to LHC would be stupid because blablabla?

You get one guess!

0celo7

@Danu Theorem (Hodge): Let $M$ be a closed region. Then Poisson's equation $\Delta\alpha=\rho$ has a solution $\alpha$ in $M$ iff $\int_M\rho \,\mathrm{vol}=0$.

ACuriousMind

8:34 PM

@Danu lol

0celo7

@Danu jaja

Danu

@0celo7 Spanish laughter? :)

0celo7

@Danu No. Yes, yes in German. :)

Danu

I'm not surprised by the references to Woit's blog ^^ He also likes to kick things

0celo7

@Danu Who is Woit and what's up with his blog? Why does he like kicking things :(

Danu

8:41 PM

@0celo7 math.columbia.edu/~woit/wordpress

See for yourself :)

ACuriousMind

@0celo7 You might call Woit the anti-Lubos

Danu

He's like... the antithesis of Lubos :D

ACuriousMind

rofl

Danu

@ACuriousMind Don't scoop me!

ACuriousMind

Great minds think alike ;)

0celo7

8:42 PM

@ACuriousMind Communist SJW who hates quantum mechanics and string theory?

Danu

@0celo7 Pretty much. What is SJW?

Also climate activist, of course! ;D

0celo7

SJW

So his blog is "not even wrong"

Trash

@Danu I don't see anything immediately wrong. Have I been infected?

Danu

@0celo7 No, Woit just likes to kick things. Just like John does

0celo7

Why would my GPU randomly spike while surfing?

Danu

@0celo7 Looks strange

ACuriousMind

8:49 PM

Hardware acceleration for Flash animations, maybe?

Also, why are you randomly monitoring your GPU usage :D

0celo7

@ACuriousMind Reasons.

@ACuriousMind I have a monitor on all the time.

And why would my GPU even be running? Does Windows not recognize integrated graphics?

@ACuriousMind What sorts of things are flash animations?

It seems I've been streaming a black screen since...shit, who knows.

ACuriousMind

@0celo7 Uhh..everything that uses the Flash player? So videos, but could also be interactive menus, maps, who knows what

0celo7

@ACuriousMind Crazy thing: it's more GPU intensive to watch YouTube videos of Oblivion than to actually play the game.

Danu

Flash! :D :P

0celo7

Maybe Witcher 3 is a flash game...that would explain the --> 0 fps.

alarge

9:27 PM

@ACuriousMind So is this andreacoser.files.wordpress.com/2012/12/lg_report.pdf something you would be looking to perhaps reproduce with your code?

ACuriousMind

@alarge Yes. Heh, the $\mathrm{SU}(2)$ result section has exactly my problem: "No phase transition is found and the theory is confining probably for all values of $\beta$."

Thank you, that is a good reference to show that I perhaps did not goof in my code!

alarge

Can you plot the sigma as a function of beta with your code?

ACuriousMind

Now I am puzzled why all these other papers from the 80s see this transition...

@alarge Not as it is currently written, but the modification should be quick. Lemme get to that

alarge

9:43 PM

Your code started the system out in an ordered phase (well, all the links were set to unitary). Would you expect your loops in this state, and did you plot anything or in any other way monitor to see that you didn't get stuck there? What would the two phases look like anyway?

ACuriousMind

@alarge I made some runs where I let it print the trace of every link for a small lattice to check that the sweep actually updates the whole lattice. It does. This is what is referred to as a "cold start". The phases should differ in the value of the Polyakov loop, I don't know whether the phases are recognizable on the level of the individual links, I think not.

0celo7

10:17 PM

@ACuriousMind you're just better than the 80s physicists! I'm not even kidding.

DanielSank

This is why I think so-called "natural units" are stupid.

0celo7

You should write the code for an 80s machine and see what you get

ACuriousMind

Ha! I see precisely what the paper says - the correlator of two Polyakov loops gets very close to zero as soon as the lattice size goes up

But for 2 grid points, it's not zero. That's nice.

0celo7

So your code is not broken?

ACuriousMind

Well, I can't say that with certainty, but it seems it has a chance to do what it's supposed to.

Ah, damn, computed the wrong thing :/

Same thing for the right thing, though.

I still can't compare any results directly because the paper varies beta, not the lattice size, but,well, it gives me hope. Many thanks, @alarge!

HDE 226868

10:37 PM

As used in this paper, is $D^{\frac{>}{<}}$ the same as $D^{><}$?

Well, forget the bar.

It's some combination of the lesser and greater functions of the components.

Danu

10:59 PM

So... I'm trying to get some sleep. But I can't sleep because someone in a nearby house is watching porn on super high volume, and I can hear everything.

@DanielSank what?

HDE 226868

@Danu Out-annoy them by playing a rendition of "The Elements Song" in high volume. Or use this strategy.

Danu

@HDE226868 I'm sleeping in the room next to my parents'. No thanks :P

HDE 226868

@Danu That's unfortunate.

ACuriousMind

@Danu You sure that the noise comes from "porn" in a "nearby house" then? :P

Danu

@ACuriousMind I'm seriously suspecting my brother, who lives a few stories below...

BUT NOT MY PARENTS PLEASE NO

Welp, it finally ended.

@HDE226868 The ordering of them usually matters in these things... I think.

HDE 226868

11:12 PM

@Danu Are we talking about my question above or your prior circumstances?

Also, this:

snigger at the h-bar. — Simon W 3 hours ago

user54412

^ private beta

ACuriousMind

@HDE226868 Linking a comment for a site in private beta is no fun :/

HDE 226868

@ACuriousMind @ChrisWhite @Danu Ah, sorry! I started a meta post regarding what we should name the chat room, and used The h Bar as an example of a fun name.

user54412

There's something hilariously ironic about Open Science being in Closed Beta.

5

ACuriousMind

@HDE226868 And SimonW doesn't think the h bar is a fun name?

user54412

11:16 PM

How big is a mozzarella? — DanielSank 44 mins ago

HDE 226868

@ACuriousMind Hard to tell. Though his suggestions were - as he admitted - pretty bad.

user54412

^^ The most pressing question of our generation.

ACuriousMind

@ChrisWhite Asking the real questions, @DanielSank

HDE 226868

@ChrisDrost Thanks. I searched the Wikipedia page on the SI syste, the NIST page, and even asked some colleagues and I couldn't find a definition of the $\text{mozz}$ unit. I know that mozzarella is available in smaller chunks and I didn't want to get confused about unit systems lest we crash pizza or something like that. — DanielSank 32 mins ago

user54412

@ACuriousMind OP is German. Does Germany have standard mozzarella sizes? It does, doesn't it?

ACuriousMind

11:19 PM

@ChrisWhite Hm...yeah, I guess you could say that. I think it's a 200g chunk of it, but I'm not 100% sure.

DanielSank

@ACuriousMind You know it. Keeping it real up in here.

@Danu Can I help you?

vzn

hi all this just opened today. encourage everyone to try it out.

oops, see above comment, its in closed beta, ok.

however... is the chat room closed? probably not! good place to hang out/ express some support etc

HDE 226868

@vzn It's open.

Though not busy.

vzn

Open Bar

Science ad libitum: General discussion for openscience.stackex...

DanielSank

Hey guys, if I have a 2D random distribution where the x projection and y projection are each Gaussian with std deviation sigma, how do I figure out the fraction of the points within some range of the center?

There must be a name for this.

user54412

11:34 PM

bi-Gaussian?

user54412

@DanielSank Is your question how to find the fraction near the center in 2D, given only the means and std devs of the projections?

DanielSank

@ChrisWhite Nope. I want to know how, given the std dev of the projections, do I calculate the expected fraction within a given radius of the center?

Which is similar.

user54412

Is that even possible? Like, consider a 45° ellipse versus a circularly symmetric distribution. They have the same projections, but not (?) the same amount within a given radius.

user54412

Also, I don't actually see the difference between what you said your problem is and what I said it is.

DanielSank

@ChrisWhite You're right, same thing.

@ChrisWhite I think I'm being dumb. Isn't this just a product of two error functions?

Actually it works out to a single erf...

Weird.

user54412

11:41 PM

I feel like you need to know the covariance. Forget the ellipse -- make it a 45° line of Gaussian density distribution. Then it's just 1 error function, since the variables are 100% aligned.

user54412

@DanielSank Even in the circular case?

user54412

You might be right.

DanielSank

@ChrisWhite I'm assuming the covariance is zero. I should have said that >.<

0celo7

Covariance?

DanielSank

@0celo7 Correlation between x and y projections.

user54412

11:43 PM

Aha. That makes things better.

ACuriousMind

@0celo7 Covariance.

0celo7

@ACuriousMind I suspected it had nothing to do with diffeomorphisms.

DanielSank

@ChrisWhite It sure does. Fortunately my data comes from quadrature demodulated noise, so the projections actually are uncorrelated :D

^ Scroll to bottom for picture.

0celo7

@DanielSank That's scary.

DanielSank

@0celo7 What do you mean?

0celo7

11:50 PM

I'd rather do a proof in HE than your crazy signal stuff.

DanielSank

@0celo7 If you actually read it you'll see it's actually all quite simple if you understand random variables.

Also, it took me two years of thinking about it before I finally understood how to do that calculation. Again, it's not hard, it's just that random processes don't behave the way we expect under algebraic manipulations.

Here's a great example.

Suppose you have a random variable $X$ which is uniformly distributed from 0 to 1.

Now define a variable $Y = X^2$.

What is the distribution of $Y$?

You don't just square the probability distribution of $X$.

0celo7

I don't know shit about random variables.

DanielSank

@0celo7 Indeed. We rarely learn about them as physicists.

This is a source of much pain, in fact.

0celo7

I could take probability and stochastics classes for my math electives.