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8:00 PM
yeah it's differentiable a.e.

Maybe I don't either lol
and of course I like r/surrealmemes

@0celóñe7 typo?

If $f:R^n\to R^m$ ($n\le m$) is Lipschitz, then the $n$-Hausdorff measure of the image of the critical set is zero
@DanielSank hmm?

does now allow alcohol

oh, not
@BalarkaSen Hmm. Is it possible to be differentiable everywhere in an open set but not $C^1$?

8:03 PM
ciao, everybody

I guess integrating any discontinuous function gets that

8:17 PM
~198 refs to "magnet" in here. adding 1 more. How One Man’s Quest To Save His Magnets Became A Massive Regulatory Battle / huffpost

8:29 PM
Are there any theories which explain why a moving charge create a magnetic field?
Why does gravity only pull? Why can't it also push like the electromagnetic force? Does it have to do with the force carriers?

@Черенки It's called special relativity :P

How come?

Anonymous

it has to do with the Lorentz law
and length contraction

8:34 PM
are you guys talking about the 1. or the 2. question

1st

Anonymous
Well, Einstein said gravity is space-time curvature rather than a force =P

especially because it's not even that true
in an expanding universe, gravity is pushing things apart in a sense

why does not my table push me
i know why it does not pull me

what

8:36 PM
why does not the matter we know push

@Черенки, почему тебя завут <<черенки>>?

you said gravity is pushing things apart

что значет?

@0celóñe7 Why? You speak "math" all the time that I don't understand.

8:38 PM
@DanielSank Uh, what?

@0celóñe7 I don't understand large fraction of what goes on in this room, but I wouldn't ask those making the associated comments to stop.

General chat for Physics Stack Exchange

Ah, smart ass Daniel

Anonymous
@Черенки I guess you should start reading relativity seriously. Your question requires a very long answer. BTW, I don't think I can help much either (because I haven't read much beyond Lorentz transforms)

I'll wait until you leave

8:39 PM
@0celóñe7 name calling, eh?
@Черенки Huh?

@DanielSank what do you mean "Huh?"

I don't understand this comment:
1 min ago, by Черенки
General chat for Physics Stack Exchange

howcome?
which part?
do you have to understand it?

Thrilling conversation

Anonymous
@DanielSank I think you understand it but you don't understand why he posted it.

Anonymous
8:41 PM
=P

@Blue Right.

Seriously why do you want to understand it
is it that big of a deal

Anonymous
Gosh.

No, it's not a big deal.
People ask questions all the time, even when it's not a big deal.

Anonymous
I should chicken out.

8:42 PM
what is a big deal

@Черенки chocolate.

i think the problem lies in the notion that we think some "things" are a big deal

I think you're making too big of a deal out of this issue about what is or is not a big deal.
:-P

indeed

So let's make a deal:

8:43 PM
oke tell me about experimental quantum devices

Let us agree not to deal in the bigness of other deals.
@Черенки I would be happy to do that if you have a particular question.

what are they

Uhh... an experimental quantum device is any device that is used in an experiment in which quantum mechanics is relevant.

ok
so what are you mainly experimenting

@BalarkaSen JP was on the h3h3 podcast
I suggest watching the meme lord

8:47 PM
@Черенки I work in a lab that is trying to build a quantum computer.
I research things related to that.

sounds nice

It is a lot of fun.

good roast

so why is your name черники?

Anonymous
@DanielSank Is that Russian ? What does it stand for in English?

Anonymous
8:51 PM
"Why is your name *****?" sounds like a strange question. :P

I can tell you why my name is what it is

Anonymous

@Blue Back in 10th grade I had a different standard user name

Anonymous
@0celóñe7 What ?

@Blue what what?
0celo7 was not always my standard
I am telling you why I am 0celo7

Anonymous
8:53 PM
@0celóñe7 What was your previous user name? And why do you call yourself 0celo ? Go ahead :D

@DanielSank its just a name

@Blue it is a mystery, but you can find the old name in a picture I've posted in this chat

Anonymous
@0celóñe7 I'll check the transcript someday. Now the other question .... what's 0celo7?

@Blue I was in 10th grade and was playing BF3 with a friend from school

Anonymous
Okay ?

8:58 PM
we ran into some people and started playing with them, did the whole friends list thing
I was playing with them for a while and they said that my name was bad
they all had metal gear solid themed names, and my favorite from MGS1 is Revolver Ocelot
So I changed it and Revolver 0celo7 is the one I was finally able to get on Xbox Live
then people just called me 0celo7, so I tend to shorten it to 0celo7 now

Anonymous
Oooo. I c. 0celo7 sounds cool though

Anonymous
My name is just my favourite color.

0

Is this legal to post my physics question here for verification only but not for answer? I just want to make sure that my question is on-topic, not off-topic, and fits the rules, like it's not too broad and etc. I have already read all the "How to ask" sections on the help center and then in ph...

any recommendations for sources to read special relativity

@ACuriousMind I think I still want to ask that

Anonymous
9:09 PM
@Черенки Start with Shankar's lectures. I found those very helpful. For book recommendations you can check the corresponding MIT OCW syllabus page for SR.

There must be a typo

@0celóñe7 What?

@ACuriousMind The deleted message.

Anonymous
@Черенки I didn't like it much

9:10 PM
@0celóñe7 Why would you delete it if you want to ask it?

@ACuriousMind Accidental deletion.

How does that happen?

@ACuriousMind Misclick on the edit screen?

Is that a question or an answer to my question? :P

Serves: 8
Good lord
6 pounds of chicken lmao
@ACuriousMind So, no answer I take it?
It doesn't make sense to me either
Clearly $M$ is open in the subspace topology (duh), so not sure what's up

9:21 PM
@0celóñe7 No idea what "relatively open" is supposed to mean in that context. Generally I'd consider "for $Y\subset Z$, $X\subset Y$ is relatively open if $X = U\cap Y$ for some open set $U\subset Z$", but that doesn't seem to be the case here

9:33 PM

9:48 PM
does anyone have a pdf for robert resnick special relativity

"teach a man to fish"

@ACuriousMind wee-ooo-wee-ooo

@AccidentalFourierTransform I do not have 20 reputation points to talk in the chat unfortunately :( So I am writing here. OK, fine, I do not care if what I described really is a classical field theory or not. What I am asking is whether "A classical theory plus a vacuum state plus creation and annihilation operators plus Born's rule" can be defined as QFT such that other results of QFT essentially are derived from this definition. That's all I ask really. If this question is a misunderstanding, then I will ask separate questions, dividing them into chunks. — Lucia Guzheim 24 hours ago
maybe someone could invite her to chat?
i dont know how to do that
or I dont even think I can

@AccidentalFourierTransform olalala

she can be invited by a mod, but still won't be able to chat

@AccidentalFourierTransform She should be able to talk in this room now.

thx m8

ohhh super ping, that sounds interesting
$[@,@]=\sigma$

I want to know more about why moving charges create a magnetic field
is special relativity the way to go
???

10:00 PM
my picture just fell off the wall
how do I put it back

spit on it
than leave it on the floor

wtf

what picture is it?

is it framed?
I want to know more about why moving charges create a magnetic field
is special relativity the way to go

@AccidentalFourierTransform family pictures
the hanger is broken

10:01 PM

how did this happen

special relativity is for kids m8

no seriously

@0celóñe7 that must be a sign. Perhaps your family doesn't love you?

@AccidentalFourierTransform or their love is so much it was too heavy for the hanger
why you gotta be negative

10:04 PM
@Черенки yes, special relativity. I mean, general relativity is better, but best to start with special relativity

thx

@Черенки (thanks autocomplete) read Feynman's lectures

I have the first volume and the 3
3.

@AccidentalFourierTransform no one less than 300 lbs

10:06 PM
YOU PEOPLE

I dont know what 300 lbs is

@AccidentalFourierTransform why did that disappear

deleted it

@AccidentalFourierTransform 50 stone
@AccidentalFourierTransform why?

YOU KNOW GREAT STUFF

10:06 PM
@Черенки pls stop annoying

ok sorry but
i did not know these websited even existed

"300 lbs to kg"

and they are soooo great

> 136.078
wft m8
@Черенки I know a lot of cool websites

ppoooost
plz

10:07 PM
no, ACM is watching

4chan.org

wow i did not know that

remember lemon party? whatever happened to it

4chan.org/boards/sci is pretty damn good
@AccidentalFourierTransform I had one the other day

one lemon party? like the one on the webpage?
interesting.

10:09 PM

@AccidentalFourierTransform Y'know, that shouldn't be your primary reason to behave yourself.

@ACuriousMind Not the primary, but without you here there would be lots of porn.

but if you are not around to observe me, do I even exist?

Sofia knew it back in the day and we know it now.

@Черенки I don't know what level you're at, but a couple of years ago, one of my friends worked on this for people transitioning from A level to undergrad physics

10:12 PM
@AccidentalFourierTransform Trickier question: Do I exist if I don't observe you?

I dont know, I'm a solipsistic

@ACuriousMind The 'I' evolves with time, so the 'I' at one moment is not the same 'I' as the next, hence the 'I' at the moment that was typed will never exist again ;)

Oooooooh, are we talking about identity?
I wrote an essay on the topic when I took a (terrible) metaphysics course in college.
I remember stapling a mobius strip with some world-lines drawn on it to the essay.
Fortunately, my grader was an ex-chemist who appreciated such things.

@DanielSank Possibly... I never did any metaphysics stuff, so... I don't really know what I'm talking about :P

10:17 PM
@Mithrandir24601 Continuity of identity is a tricky question. If the I at one moment is not the same as the I at the next, then what does the phrase "the I" even denote?

@ACuriousMind It's a function, so it should really be 'I(t)'

and the question is meaningless unless you define a topology anyway

indeed, continuous wrt. which topology?

It's not tricky. It only feels tricky because philosophers want job security.
rant rant rant rant rant \rant

I could say the same thing about quantum computing ;-)

10:21 PM
@Mithrandir24601 Ah, then we end up at the question why we would consider $I_1(t_1)$ and $I_1(t_2)$ "the same" but markedly different from $I_2(t_2)$, where $I_i$ are the identity functions associated to different brains.

BTW no Rick and Morty fans here?

@ACuriousMind but they're not the same - that's what I (though I) was saying

@AccidentalFourierTransform Why would you think not?

@Mithrandir24601 Ah, "the same" was a poor choice of phrasing. We generally feel that all the $I_1(t)$ are closer "related" than $I_2$. If you don't hold that view. If you disavow that view, then you're off the hook.

10:25 PM
@AccidentalFourierTransform Nobody says quantum computing is complicated.

@ACuriousMind Hmm... It's a topology problem :P

The other day someone from the WSJ asked me to explain why quantum mechanics is weird.
I went off on a rather well-reasoned and carefully articulated rant about how it's not weird and that people only say that to sound cool.
I even went so far as to say that Feynman's famous statement that {anyone who thinks they understand quantum mechanics is wrong} is destructive, stupid, and should not be repeated.

and now you are saying that it is not weird to sound super-cool 🙄
but yeah, Feynman's full of crap there
oh, did we have our daily rant about how Feynman is overrated?
I think not

::raises hand::
I'll do it!

@ACuriousMind it's continuous in one direction (time), but discrete in another (different brains) - as such, some $I_j\left( t_1\right)$s are closer to $I_i\left( t_1\right)$ than $I_i\left( t_2\right)$

10:28 PM
Feynman was incredible. He was one of the best calculators ever.

brains are not discrete ffs

He was brilliant, no question.
However, his technical books kind of suck.

his lectures are nice dude

At least, I got little/nothing out of the famous lecture series.
Meh.

well, when did you read them?

10:29 PM
I was a student.

Feynman was, I'm told, not the nicest of people

I've read a few of this things. They're vague and wishy-washy and try to pretend that you don't need math, which is complete and utter crap.
I really strongly dislike that.
I don't even want rigorous math, but telling me that you can understand QFT without math is ridiculous.

oh yeah his QED book is awful

"You just add up the little arrows" <-- Oh give me a f------ break.

"Chased women around the lab" is something I feel like I can quote (I think that one was about Feynman)

10:30 PM
That doesn't make him not nice.

@DanielSank That was the 'nice' bit

You know, my dad actually sat next to him on a plane once.

Apparently the movie player wasn't working. My dad noticed that the plane was full of physicists and commented to Feynman that you'd think on a plane full of physicists you'd have someone who could fix a video player.

is it on instagram?

10:31 PM
Feynman apparently said "Nah, we're all theorists".
I found that particularly funny because Feynman was quite a tinkerer in his youth.

anywayz
off to bed
l8r

@DanielSank I never understood why he made these strange claims, given that there's that famous "magnets" interview where he pretty much says that he can't explain the fundamental theory of magnetism without the other person knowing a bunch of prerequisites/math.

@AccidentalFourierTransform Night! See you in... 20.5 hours...
(on here)

10:49 PM
When I make a matrix of eigenvectors to change the basis of the matrix, does the non-commutative nature of matrices make how I make the matrix of eigenvectors important? As in, one column before the other or vice versa

It depends.

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