The h Bar

4:00 PM

In the classical picture, a single wave arrives at the slits and is split into two new waves originating from the slits. "Superposition" means that the total intensity is obtained by first adding the waves and then squaring them.

Shing

now it start making sense to me, thanks for the help

I probably have a long way to go in doing the problem sets in order to develop my quantum picture. it is so strange.

skill patrol

There is really only one way to make something strange into something familiar and that is practice :-)

0celo7

@skillpatrol eh

user54412

27

Q: Should I encourage foreign students to adopt local handwriting customs?

I am an American teaching in a US university, and I've noticed that many foreign students come with their own handwriting customs for writing English. In particular I've noticed that Indian students often write the letter 'x' so that it (to me, anyway, and probably to many Americans) resembles an...

etiquette

0celo7

@ACuriousMind how do you handwrite frak letters

ACuriousMind

4:11 PM

@0celo7 I'm shit at writing fraktur, so I don't

0celo7

@ChrisWhite ?

@ACuriousMind practice!

ACuriousMind

Not worth it

skill patrol

agreed^

ACuriousMind

The only two instances where fraktur is customary is for Lie algebras and ideals. Usually the notion isn't so overloaded that I can'T just use normal letters

0celo7

mm, that was mean

@skillpatrol your face is strange

you always have this weird look

My programmer sister can't even write by hand anymore

She hasn't had a need to for 5 years

at least

(removed)

what did that say, I wonder

ACuriousMind

4:15 PM

Well, fields in which you have to write formulas are really the only real use case for handwriting, I think, because the average person writes far quicker by hand than TeXing them.

Slereah

yeah I tend to write equations a lot by hand before I'll begin texing

skill patrol

there is no such thing as a cursively written equals sign :P

Slereah

what about $\approx$

obe

Is this kind of music weird?

am I weird for liking it?

skill patrol

@Slereah that's approximately

0celo7

4:18 PM

@obe Will judge that later, in class now.

My default: if you have to ask that, then yes.

obe

It's so cool though, if you listen carefully it has some kind of structure.

ACuriousMind

@obe Yes.

skill patrol

@obe "thank you for the noise you left behind, RIP"

ACuriousMind

But that's okay

obe

@skillpatrol oh yeah aube died.

few years ago :(

@ACuriousMind It becomes really interesting at 18:03.

0celo7

4:26 PM

@ACuriousMind You only say that because you're weird :^)

Here you guys go. imgur.com/gunJGPk

Huy

-5

0celo7

Yup, fucking weight vs. mass.

Imperial units are literally the worst

Huy

I've never in my life heard of a distinction

0celo7

Because you're a scrub

Huy

yes

ACuriousMind

4:36 PM

@Huy While synonyms in everyday language, physicists distinguish between the mass of an object and the force the Earth's gravity exerts on that mass, which is called the weight.

Most scales you have measure the weight and then convert that to mass.

0celo7

^

Huy

is that like schwere und träge Masse?

ACuriousMind

@Huy Nope

0celo7

Crappy thing is that problems in metric have mass as a given and problems in imperial have weight as a given.

Huy

how do you call the two things in German then?

frankly I've never seen the word weight being used in any literature

always mass

ACuriousMind

4:38 PM

@Huy Gewicht (oder Gewichtskraft) vs. Masse.

Huy

Gewichtskraft seems more reasonable

Gewicht is Masse to me :P

ACuriousMind

@Huy Just like weight is mass to non-physicists in English

0celo7

I know the difference!!

I just forgot to convert because

Reasons

So no comments on my handwriting?

Huy

is that your handwriting when you're copying the prof who is writing at furiously fast speed?

0celo7

And if you look carefully I messed up weight/mass only at one point.

@Huy Never been in that situation.

Huy

4:42 PM

???

skull petrol

There's also the use: his argument doesn't carry much weight :P

0celo7

@Huy What's there not to understand?

skull petrol

If he knew that^ he would understand

ACuriousMind

@0celo7 He is surprised that you never had to copy a fast-writing prof

0celo7

@ACuriousMind I'm a freshman in introductory classes. Everything is trivial, I barely even take notes.

skull petrol

4:47 PM

This is his first exposure to professors.

ACuriousMind

"Everything is trivial"...except for quadratic equations.

0celo7

I hate you 😰

Wonder if that emoji shows up on PCs

skull petrol

💀

0celo7

👽

^ ACM

skull petrol

😛

0celo7

4:50 PM

🔫👿 time to get revenge

skull petrol

🇩🇪 vs 🇺🇸

0celo7

I should get citizenship

Then I wouldn't be "that crazy American"

skull petrol

🔞

0celo7

Most emojis are useless.

skull petrol

yup

0celo7

4:53 PM

Does @ACuriousMind even know how to use a gun?

Slereah

😽

ACuriousMind

@0celo7 No, why would I?

Huy

to defend yourself from all other gunholders in your country!

ACuriousMind

Seems legit

0celo7

@ACuriousMind It's fun, interesting, practical.

Slereah

4:54 PM

🗾

JAPAN

Huy

sorry but how is it fun

0celo7

What kind of question is that?

Slereah

☢🗾☢

0celo7

Hitting a torso sized target at 1000 meters is fun.

The challenge is great!

Slereah

I like how in my font, the gun emoji is a raygun

ACuriousMind

4:56 PM

I think if I wanted to shoot at things for fun, I'd prefer a bow

Slereah

It reeks of commitee design

0celo7

Bows are fun too. But it's a whole different game.

Slereah

"We can't have a real gun, think of the children!"

0celo7

@ACuriousMind I'm not talking about spray and pray for shits and giggles. Although that is fun, too.

Slereah

Is it considered poor taste to write equations with emojis

Emoji index

ACuriousMind

4:59 PM

@Slereah abstrusegoose.com/345

0celo7

Yes! Dynamical emoji index

Slereah

$x^🎠$

IT WORKS

0celo7

Lel

Huy

I'll be using emojis instead of Greek letters in my future papers.

Slereah

$🐢_{🐰🐹} + \frac{1}{2} 🐘_{🐰🐹} 🐢_{🐑🐯}🐘^{🐑🐯} = 🐺_{🐰🐹}$

Einstein field equation

Huy

5:02 PM

exactly

I recognized them

0celo7

@ACuriousMind why a bow

because Legolas

Who?

stop trolling me

^

5:04 PM

My mom said LoTR is too violent

Huy

she's right

0celo7

I haven't watched the Simpsons, Family Guy or Back to the Future but LoTR is trolling?

Huy

all of it is trolling

ACuriousMind

@0celo7 hm, right, should've expected that after Simpsons

0celo7

Seriously? Ok, I have watched LoTR, but the others aren't.

ACuriousMind

5:07 PM

Still, you could also have, y'know, read it

0celo7

Name a movie series that you thing most people have seen.

John Duffield

@bolbteppa : yes. This is the crucial thing you need to know. Paragraph 2:

0celo7

@ACuriousMind Never read it. Don't plan to, either.

Huy

LotR

Star Wars

Godfather

nowadays: Nolan Batman

pop-answer: Pirates of the Carribean

0celo7

Yes, yes. No. (Technically yes but was drunk) Yes. Yes.

Huy

5:09 PM

Matrix, at least 1

John Duffield

Plus the simple fact that at the event horizon the coordinate speed of light is zero. And it can't get less than that.

ACuriousMind

@Huy Matrix had no sequels

Galois in the Field

Oh @0celo7 is trolling again is he?

0celo7

I have seen the first. Was instructed to stop there.

Huy

why were you drunk watching Godfather, @0celo7

that's not a movie I wanna watch when drunk

Galois in the Field

5:12 PM

I haven't seen the godfather or Nolan Batman

0celo7

That was my LA trip. The goal was to not be not drunk, I think.

Huy

isn't drinking illegal under 21 in USA?

Galois in the Field

We drink at 13 here in Australia, makes you tough

Huy

and yet you've seen neither Godfather nor Nolan's Batman. not so tough anymore.

Galois in the Field

:'(

Huy

5:15 PM

catch up, it's only 6 movies

0celo7

@Huy Yes, so?

Galois in the Field

wtf

Huy

@0celo7: I will report you to the police

Galois in the Field

Hahaha

0celo7

@Huy Do it. There's no evidence of a crime.

Huy

5:17 PM

@0celo7: dropbox.com/s/ltc9x2sp64ctcs0/movies.txt?dl=0 here's my current collection. suggest something that I might like that's not in there

btw not all of it is there because I like it. some movies I just wanted to see to know what they're about. :P

Galois in the Field

Silverlining playbook is good to watch with a lady friend

Huy

I know :)

pretty sure it's in there, @Galois

Galois in the Field

It is, I was surprised!

0celo7

My favorite movies of all time are the Transformers.

Galois in the Field

wut

Still trolling I hope

Huy

5:19 PM

so you like Megan Fox?

John Duffield

@Shing : it's only strange if you thing of the electron as some kind of billiard ball. It isn't. It has a wave nature. Note that in atomic orbitals "electrons exist as standing waves". IMHO the best advice I ever heard was the electron's field is what it is. It isn't some speck that has a field, it is field, and there is no speck. Hence it goes through both slits.

But when you detect it something akin to an optical Fourier transform occurs, and it's transformed into a dot on the screen. Or if you detect it at one of the slits, it's transformed into a dot and goes through that slit only. No magic or mystery or many-worlds multiverse is required.

0celo7

@GaloisintheField No. Great action, great visuals.

Huy

@GaloisintheField: It's mostly there because of the Jennifer-Lawrence-effect.

@0celo7: the first one was decent, the others meh, imo

Galois in the Field

@Huy Oh, not Bradley Cooper? :P

Huy

I prefer Hugh Grant <3

Galois in the Field

5:21 PM

He's so dreamy

Huy

he's a really funny guy too it seems, did you see his AMA he did a while back?

Galois in the Field

Nah I didn't, on reddit?

Huy

yea, reddit.com/r/IAmA/comments/2iv469/i_am_hugh_grant_amaa

@0celo7: Megan and this are the only reasons to watch Transformers imo: youtube.com/watch?v=4H0JDomv8ac

Galois in the Field

That's a pretty beast soundtrack(composition?)

Huy

yeah, I love how you can really tell he was Zimmer's student

0celo7

5:25 PM

How about all the destruction and cool transformations

Huy

could as well be a Batman movie

Galois in the Field

Never seen the batman

Huy

you mean Krümmungstransformationen?

@Galois watch it, but in order

0celo7

Oh I figured out what he meant by that

If you contract the Riemann tensor with two vectors it's an endomorphism on the tangent space

So a linear transformation that depends on curvature

Huy

@0celo7: did you watch Gladiator?

0celo7

5:46 PM

@Huy Hmm, maybe. What's it about?

Huy

Maximus Decimus Meridius

0celo7

@Slereah hehe

@Huy I don't speak French...

Huy

so you haven't seen it

this is depressing

0celo7

Oh, that one. I might have seen the beginning.

I'm not a big movie person.

Huy

I can tell

what do you like apart from physics and games

and drinking

0celo7

5:49 PM

I don't even like physics

Or drinking

Huy

ic

why do it if you don't like it

0celo7

@Huy To forget the pain of being shit at math.

Huy

makes sense

Slereah

@0celo7 Hard to find the appropriate animal for the metric tensor or the Ricci tensor

0celo7

@obe Uh, that's very strange.

Let's put on some 2011 hardstyle.

Huy

5:53 PM

-_-

0celo7

@Huy Oh no you too!

Huy

-_-

0celo7

Your face is all messed up D:

Huy

:(

0celo7

I mean, I get the eyes, but your mouth should not look like that

Huy

5:53 PM

-.-

0celo7

There we go!

Huy

^.^

0celo7

wtf

you're not a Japanese gril

Huy

how do you know

maybe I am but I tell people on the internet I'm a guy because otherwise everyone would be hitting on me

ACuriousMind

Since when can grills talk?

Oh

You meant 'girl'

Huy

5:55 PM

he can neither read nor write

0celo7

@ACuriousMind That's what I said.

Oh that's right, you're a normie.

Yes, I meant "human female"

AHHHHHHH @Slereah I HATE YOU

I'm looking at PDE books now

I have no hope of understanding them

Huy

why aren't you in Steam these days

0celo7

Steam? Oh because my PC partition is freaking out, I mainly use OSX now.

It doesn't open Steam on startup.

the $1/2$ in the Einstein equations kinda sucks, doesn't it?

ruins the aesthetic

@Huy why are you so mean

ACuriousMind

@0celo7 One could absorb it into the definition of the...Elephant, I guess

0celo7

@ACuriousMind no

because then you'd change the turtle

turtle is the second derivative of the elephant

ACuriousMind

6:03 PM

That's stupid, how is a turtle descended from an elephant?

0celo7

the Einstein equations are a mess

@ACuriousMind bundle descent, duh!

Slereah

Maybe we could combine this with Penrose notation

Indexless elephants

0celo7

DO ITTTTT

Slereah

$🐘^🐘^🐘^🐘^🐘$

Hm

Too many elephant powers

$🐘^🐘^🐘$

Even 3 is too much

I am sad

$🐘^🐘_🐘$

Tiny elephant herd

$\hat 🐘$

0celo7

lol

Slereah

6:05 PM

Woops

Can't hat the elephant

AngusTheMan

The stresses and difficulties of physics, chemistry or maths is NOTHING compared to asking that girl you like out :|

0celo7

chemistry is just electron shell physics

Slereah

@AngusTheMan : Have you ever spent 400 years asking a girl

AngusTheMan

feels like it

0celo7

@Slereah have you??

Slereah

6:07 PM

Or in the case of the 5th Euclid axiom, about 2000 years

0celo7

lol

Slereah

Took a while to prove that it was indeed an axiom!

0celo7

you're an axiom

Slereah

I am.

0celo7

B-Front & Frequencerz - Delusion [Official Preview] [Fusion 190]

►

Am I weird for liking this music?

obe

6:09 PM

Duh you are.

0celo7

8GB RAM used. Not bad.

Slereah

Hm

Unicorn emoji doesn't display in my font

0celo7

How did I function when I only had 4?

16 is glorious.

Slereah

Sad

$\partial_{\mu}\bar{👻}^{a}\partial^{\mu}👻^{a}+gf^{abc}\left(\partial^{\mu}\bar‌{👻}^{a}\right)A_{\mu}^{b}👻^{c}$

3

heheheh

0celo7

@Huy do you get that?

aren't you missing something

the group indices aren't matching up

Huy

6:12 PM

hm, I don't think I get that

0celo7

first term

Slereah

oh yeah, both are supposed to be a

0celo7

there we go

Huy

can you give me a hint?

0celo7

@Huy gauge theory

Huy

6:13 PM

then probably no

I'm terrible at any gauge stuff

Slereah

Those are fadeev popov ghosts

Hence hilarious

0celo7

someone pls give me a 2880x1800p wallpaper

I need to switch

👯

wtf is that

6:14 PM

👼 < I did not know unicode had a dead baby in it

0celo7

@Huy no

Huy

a 2880 x 1800 wallpaper

but... you said...

0celo7

a GOOD one

Huy

wow, so picky

0celo7

@obe You're the one who listens to white noise :P

Slereah

6:15 PM

Why not black noise

You racist

IIRC there's a few color variant of noise

White, grey, blue, red

Pink I think?

AngusTheMan

brown

Slereah

Colors of noise

In audio engineering, electronics, physics, and many other fields, the color of a noise signal (a signal produced by a stochastic process) is generally understood to be some broad characteristic of its power spectrum. Different colors of noise have significantly different properties: for example, as audio signals they will sound different to human ears, and as images they will have a visibly different texture. Therefore, each application typically requires noise of a specific color. This sense of 'color' for noise signals is similar to the concept of timbre in music (which is also called "tone...

AngusTheMan

coloured noise is great to go sleep to tho

that or like a washing machine hum

0celo7

G-Eazy - I Mean It (Official Music Video) ft. Remo

►

why is everyone here so strange

Huy

I'm normal

0celo7

6:18 PM

I'm like the only normal one.

Huy

you and me both

AngusTheMan

Lil Dicky - $ave Dat Money feat. Fetty Wap and Rich Homie Quan (Official Music Video)

►

Slereah

I wonder if I can set a record for most consecutive not answered questions

0celo7

Rich Homie Quan is the shit.

Huy

Test 👍

AngusTheMan

6:23 PM

He really is ..

0celo7

6:34 PM

@Huy how much do you know about the calculus of variations?

Huy

just a bit

why

0celo7

Do you know how to prove the statement at the bottom?

Huy

what does "contained in a central field" mean?

0celo7

he explains it literally right above...

Huy

so?

Slereah

6:36 PM

Who has the time to scroll up

0celo7

I don't understand your question

oh look, Satan

Slereah

👿

Booooh

$^👿_👿👿^👿_👿$

Pentasatan

0celo7

OH GOD

Huy

sorry that's too much to read for me atm

I'm tired and have a headache

Ghost

@Huy have a rest

Huy

6:39 PM

I will soon

0celo7

@Huy HE WILL STEAL YOUR SOUL WHEN FALL ASLEEP

Ghost

@Huy has it been a long day?

Huy

all days are too long when being sick

Ghost

@Huy that is true - hope you get better soon! (definitely get some rest)

0celo7

no solve my problem first

then you can slep

Huy

6:43 PM

pls

ACuriousMind

@0celo7 Why do you keep asking the people here and not just post it on math.SE?

0celo7

@ACuriousMind It would be a homework question.

ACuriousMind

They're completely fine on math.SE with you posting homework questions.

0celo7

And Freire said he would explain it to me eventually, it's a nontrivial theorem in VC.

Ghost

@Huy rest first, answer questions (if you choose to) later

Huy

6:44 PM

all I remember is $\frac{d}{dt} \frac{\partial L}{\partial \dot{q}_\alpha} - \frac{\partial L}{\partial q_\alpha} = 0$ or something along those lines

0celo7

@ACuriousMind You've trained me so that I refuse to ask those types of questions now.

YOU RUINED ME

hello @ACuriousMind!

Hi @Ghost

how are you?

hehe JD's answer on the FLRW question is -4

ACuriousMind

6:47 PM

@Ghost Fine, thanks. Although I'm getting hungry

Ghost

@ACuriousMind eat!

0celo7

wow I bet he downvoted my answer!

Slereah

His lowest rated answer is -10

Huy

nah it was me

Slereah

Well, the ones that were not deleted

ACuriousMind

6:47 PM

Have to go shopping first :/

But I think I will do that now

0celo7

Good luck @ACuriousMind

ACuriousMind

I'll be back!

0celo7

Not if you get shot or something D:

Heidelberg is dangerous

Ghost

@ACuriousMind have fun shopping!

Slereah

Hm

speaking of

0

Q: How can quantum wavefunctions be smooth/continuous when particles are created/destroyed/changed?

My (admittedly limited) understanding of the Schrodinger equation tells me that the vector differential operators are only meaningful over a differentiable phase space. For example, if the dimensions of my phase space are the Euclidean coordinates of $N$ featureless point particles, then it make...

quantum-mechanics quantum-field-theory wavefunction schroedinger-equation

Should I flag the Bad Answer

0celo7

6:52 PM

-5

A: Why does the FLRW metric assume constant curvature?

The FLRW metric starts with "the assumption of homogeneity and isotropy of space". But Einstein described a gravitational field as space that is "neither homogeneous nor isotropic" : Hence setting expansion aside, for the universe as a whole there's no overall gravitational field, and light go...