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2:00 PM
@0celóñe7 Why are these random dumb shit topologies named after people
 
@Secret sounds almost fun
I'm wondering what I can read at work that looks technical enough to not get questions asked, as right now there's lilttle work to do
 
@BalarkaSen It should be read as "topology of a Schwarzschild blackhole", not as "Schwarzschild topology" meaning the actual topology is named after Schwarzschild.
 
@ACuriousMind Ahh. Well, I was guessing it has something to do with topology near a singularity of the spacetime (whatever that means!).
I was making a semi-humorous comment. It's just that I have seen this in the context of moduli spaces too: I waited in a talk for a few hours for them to define a clever topology on the Teichmuller space of genus $g \geq 2$ surfaces and it turned out to be $\Bbb R^{6g - 6}$. Boo.
 
@BalarkaSen In this case, the singularity is a pp curvature singularity
 
snek or not, it's prevneting me from enjoying my PhD, grrr
 
2:03 PM
$R^{\mu\nu\rho\sigma}R_{\mu\nu\rho\sigma}\to\infty$ somehow
 
@0celóñe7 What does R over superscript mean?
 
I need to make the font of this poster smaller
there's no room
 
@BalarkaSen what
 
Ok no I am having trouble interpreting that index notation
Sorry for being silly
 
2:05 PM
@BalarkaSen That's the Riemann tensor and I've raised/lowered all indices
 
@Secret perhaps it is time to put the chat room on the back burner?
 
a pp curvature singularity is when a polynomial in the Riemann tensor blows up
 
Ah, alright. Makes sense.
 
heheheh
pp
 
Thought it's hard to interpret "blows up" because the point where it "blows up" isn't in the manifold
how many random people at a college science fair are gonna understand this
 
2:06 PM
2/10
 
will not understand
 
That is called a scalar singularity
 
I don't know what a college science fair is.
 
$4\pi G=1$ pls
 
2:07 PM
@ACuriousMind people presenting posters on summer research
 
@0celóñe7 Yeah, that...doesn't mean much to me :P
 
@ACuriousMind Me neither, hence why I am asking
@rob my advisor is completely unhelpful, is there a time I can call you about this
 
Open to the public?
 
@skullpatrol yeah
 
Tough call.
 
2:09 PM
@ACuriousMind 90% of these research projects are on stuff like psychology, biology, bioengineering, etc., where the basic concepts can be understood without too much difficulty
I don't think anyone there will understand what a fixed point theorem is
 
does it matter?
 
@BalarkaSen yes
 
why
are you going to be executed if nobody understands your poster
 
because I want to get more money from these people
 
then make it fun
use buzz words
make it flash
 
2:11 PM
put a picture of neil degrasse tyson in your poster
as background
 
@djsmiley2k Quantum black hole cohomology
 
and put on the title "IS MATH RELATED TO SCIENCE?"
absolute banger 10/10
 
Sadly I submitted an abstract
this would be much easier if I just did an elliptic regularity poster
no one would even bother asking questions
I do have buzzwords like "albert einstein" "black holes" etc.
@ACuriousMind @Slereah did you read the thingie above? I appreciate thoughts
 
@0celóñe7 I think it will be almost completely arcane to someone not studying math or physics.
 
@ACuriousMind Do you agree that there is likely no way to make it un-arcane?
 
2:14 PM
@0celóñe7 Well, I don't know exactly what your project was about, but yes, I think it is likely you cannot make a layperson understand what you did in the space of a poster.
 
@ACuriousMind the project is about existence/uniqueness theorems for static, spherically symmetric stellar models in the presense of a cosmological constant
also various inequalities and qualitative behavior of polytropes
 
Yeah, I think you won't be able to make the average person understand more "There's this equation that matters for stars and I looked at its solutions" :P
Do you have any pictures you could put on there?
 
@ACuriousMind Working on those
trying to generate lots of graphs with Matlab
I can plot density/pressure vs. radius
 
I think it might be a good idea to take a few pictures you think look nice and then focus the poster on trying to explain what's visible in the picture and why it matters
 
@ACuriousMind the pictures are a part of the project
maybe I should put the picture from JD's avatar
 
2:18 PM
@0celóñe7 Sure
 
I don't really have that much space though
 
I just thought that instead of trying to explain the project from beginning to end, you might start just explaining one specific result
I.e. don't start with "GR works like this:", but "Here's a picture of my results, and what it shows is that:"
 
@ACuriousMind yeah
 
Show them The Evidence
 
@skullpatrol Y'know, that joke is getting pretty old :P
And you already made it at least once with respect to this same poster.
 
2:23 PM
Rule 1 of dank memes: Don't beat a dead meme to further layers of death.
 
@BalarkaSen one of my new profs has some basic memes
 
the only thing that confuses me is the notation for the eigenspace
What does the $V^{m_i}_{w_i}$ mean
 
Shankar is good
 
Is $m_i$ the dimensionality?
 
@Phase probably
 
2:26 PM
RIP
 
Is it not? I can't tell
It seems reasonable
 
so it's V, of dimensionality $m_i$ with eigenvalues of the form $\omega_i$? What does he mean when he writes the identity between $/omega_i$ and $i$
 
I really don't think JD should have been suspended from chat.
He was ok here.
 
@Phase The three dashes mean it's a definition, i.e. it's not an identity so much as declaring that both of these notations refer to the same space.
 
So he just means an eigenspace with a number of eigenvalues equal to it's dimensionality?
 
2:30 PM
Yes
 
I guess I assumed that holds true for all eigenspaces
are there cases where it doesnt?
 
@Phase I think $m_i$ is the dimension of the eigenspace, and he's saying that you can index the eigenspace either by it's actual eigenvalue $\omega_i$ or just by $i$ (i.e. saying "the space with eigenvalue $\omega_i$" is the same as "the space with the $i$-th eigenvalue")
 
Eigenspaces only span degenerate eigenvectors right?
If you have 1 non-degenerate value and a degenerate value that applies to 3 eigenvectors
do you just have $V^3$?
whoops wrote 4 instead of 3
 
I don't understand the question
An eigenspace is the space spanned by all eigenvectors of the same eigenvalue
E.g. if there are 3 eigenvectors with eigenvalue $\omega_2$, you'd write $V^3_{\omega_2}$ for their eigenspace in this notation
 
Right, even if it was a 4x4 matrix with 1 non-degenerate value
Thanks, : )
 
2:36 PM
Can we get back to my question?
Why did JD get such a long chat room ban?
 
Sid
Who's JD?
 
Yeah idk either
 
Jul 19 at 12:14, by AccidentalFourierTransform
JD Salinger
 
Anonymous
@BalarkaSen I'm studying now. Can we do it at around 11:30 pm?
 
@skullpatrol it was g o h s who banned him
Don't poke the hornet nest
 
2:40 PM
Thnx
I didn't know.
 
g o h s?
Is this some kind of SE deity?
 
Don't ask.
 
Sid
It is. Now, pretend you never saw that
 
you can't just say that and then "dont ask"
 
2:41 PM
does he have some kind of script that notifies him whenever someone mentions his name?
 
@skullpatrol Because he was a continual disruptive influence. Please drop the topic, we will not further discuss users here where they cannot respond themselves.
 
He is like voldemort, just be quiet
 
._.
 
@Phase Shog9, one of the SE Community Managers.
 
shog shog SHOG shog SHOG sHoG shog Shog SHoG shog shog SHOG shog SHOG sHoG shog Shog SHoG shog shog SHOG shog SHOG sHoG shog Shog SHoG
 
2:42 PM
:O
RIP @AccidentalFourierTransform
 
Some people seem very paranoid about drawing his attention. Draw conclusions from that as you will.
 
@Blue Sure!
 
Huh
 
Sid
@rob How good or bad is Python?
 
2:43 PM
Jesus Christ
 
Sid
In comparison to, say, Javascript or C++?
 
So I guess this Shog dude is fairly strict as a moderator?
how often do people in this chat get penalised directly by external moderators?
 
on a daily basis
 
Me? Almost daily.
 
I have seen shog9 #rekt some people and some chats.
 
2:44 PM
@ACuriousMind projective representations?
 
He deleted a chat once
For no good reason
 
Yeah (to the first sentence)
 
@Phase All moderators are chat moderators. Please do not think of moderators from other sites as "external moderators".
@AccidentalFourierTransform Hmmm?
 
Anonymous
@BalarkaSen Okay :)
 
@BalarkaSen there was a good reason?
 
2:45 PM
@ACuriousMind well, projective representations or not?
 
@AccidentalFourierTransform Yes.
 
@ACuriousMind what?
 
@ACuriousMind Moderators from other groups then I suppose. How are they aware when stuff 'needs' to be addressed? Do all Moderators get flagged when something in a chat is reported?
 
If you are thinking about the SiFi chat, yes. It is folly to think moderators, especially community moderators, especially one of the bigshot community moderators like Shog9, would act without any reason.
But let us not discuss this here. What CM's do to chats is of no business to me as long as it doesn't hurt me. Ignorance is bliss. :P
 
2:47 PM
Why is everyone so secretive about moderation
The SE culture is very strange
 
Please stop now guys.
 
Club penguin was also secretive about moderation
 
Sid
@Phase and 10k+ users of the site, I think
 
look what happened
 
The moderator community is the Global Elite reptiles that Alex warned us about
^pls dont ban
 
2:47 PM
SE is worse than 4chan
 
It can get worse.
 
AFT please don't joke about Club Penguin
 
@Phase A rude/offensive flag is visible to all users with more than 10k total rep (and this is one of the reasons why response to such flags has a high variance), flags for moderator attention are visible to all moderators.
 
I'll ask almighty mod gods to ban u
Are Mod notification boxes just constantly spammed with flags then?
 
@ACuriousMind I need to know what happens in the mod chat
 
2:49 PM
Whenever I talk to Indians, yes.
 
you guys share the best memes, dont you
 
@skullpatrol Look, starting this discussion and now asking to stop is pretty inconsistent. Why did you ask the question if this was not the result you expected? (I agree it would be better to drop it, but what was your intention here?)
 
13 mins ago, by skullpatrol
Can we get back to my question?
 
What is Club Penguin?
 
2:49 PM
What is club penguin
 
@Phase No, chat flags are actually pretty rare.
 
@ACuriousMind can a mod dismiss a flag on one of their comments?
 
> What is Club Penguin?
 
The last bastion of freedom
It got shut down
 
2:50 PM
Club Penguin was rare in that the speedrunning community was singlemindedly devoted to getting banned
Remnants of a dead society
 
Sid
@0celóñe7 Oh, come on. You talk to Balarka, to me and I can say for myself, I have never flagged anyone's posts..
 
Fug, YT really needs to auto mute
@Sid Are you the fish guy? I got a billion flags from that
@BalarkaSen is a meme lord, we are on the same wavelength
 
Sid
and I didn't flag it. Apparently I was somehow insulted without me even realizing it
 
If someone said "I'm insulted, pleas stop" I would. That never happens.
3rd parties just flag everything and get a hit from the flag lottery.
 
2:54 PM
Hey @0celóñe7 are you feeling optimistic or [reasonably] hopeless regarding this abomination
 
@Phase im blue, ill beat off a guy, ill beat off a guy, ill beat off a guy...
sorry I couldn't resist humming the tune
so good
 
@BalarkaSen b&
Can you get banned from SE or the SE chat for bringing up Pseudoscience constantly?
 
Yes
 
honestly, is there like an online Mod Handbook for this site? I'd be interested to see what it entails
 
Ask on meta
 
2:56 PM
@Phase You do not get banned for specific content unless that content inherently runs afoul of Be Nice.
 
Make sure to Be Nice to carp.
Duck salmon though
 
Trout?
 
Those are sacred too
I've never had deboned trout
 
don't say "sex" either
 
I'm as much of a fan of Trout as the next guy but I wish they'd stop waving their sexuality around in my face
 
2:58 PM
Guys, I have a question. The range of a force is inversely proportional to the mass of the force carrier, right? But gluons which are force carriers of the Strong force are massless and still the range of strong force is so small. why?
 
something something colour singlet
 
My question @ACuriousMind was answered by 0celóñe7
 
@QuamosM87 What do you mean by "the range of strong force is so small"?
What is true is that we have confinement, a quantum phenomenon that prevents there being free objects charged under the strong force.
So you can't really talk about the classical "range" of the strong force, since there are no free charges it could act on to begin with
 
the strong force is bound to the nucleus right? so it acts upto a short distance. for em force the photons are massless, so the range is infinite
wait let me give to the link
 
I should make doublebig poster that explains all of GR
 
3:04 PM
@QuamosM87 Ah, that is the residual strong force (also "nuclear force") that is modelled by being mediated by massive pions, not gluons.
 
@ACuriousMind We need new avatars
 
Put a picture of Hawking on it.
 
He's not pretty
 
He's an attention grabber.
 
0
Q: Why you can use mathjax in this website?

Erez ZrihenI have just noticed that you can use mathjax in this website, i.e. in Physics meta, but why? Here for example: $E=mc^2$ But mathjax is used only when you ask serious question in physics or mathematics and etc..., but serious question in physics should not be asked here on meta, but on physics ...

0
Q: Can I get banned in this website?

Erez ZrihenCan I get banned in this website? Shall the system ban me if I am asking too many bad questions here?

 
3:07 PM
oh okay now i get it. thanks @ACuriousMind
put a picture of feynman :-P
 
@QuamosM87 Also, since I just read it on that page: The range of a force is not limited "by the uncertainty principle". That's a misuse of the uncertainty principle. The proper way to derive the force associated to a certain mediating particle is to do the calculation I outline in this post, which yields that the force of a particle with mass $m$ goes as $\exp(-mr)/r^2$.
 
How old were you when you learned the HUP? @ACuriousMind
 
Anonymous
@skullpatrol Of course he knew it since birth.
 
Anonymous
AI's are usually pre-programmed. :P
 
He's does seem unusually comfortable with it.
 
3:22 PM
@skullpatrol Uh...in its proper form (and not just the handwavy $\delta x \delta p \geq \hbar$ without derivation), 19, I guess.
 
Anonymous
I learnt the proof using Cauchy Schwarz few days back. Tbh it's a bit confusing. I need to revise it a few times.
 
@Blue also it's wrong :) or at least not completely correct
 
Anonymous
@0celóñe7 Huh. It seems everything is wrong in Physics
 
I will tell you details in a few years when you are learning Functional Analysis
 
Anonymous
Thanks. Will be waiting :P
 
Anonymous
3:32 PM
@0celóñe7 You gonna go for a PhD after your undergrad?
 
@ACuriousMind you helped me earlier. I was wondering if you could help again! In the last example here (tcm.phy.cam.ac.uk/~bds10/aqp/handout_spin.pdf), I understand how to get |0,0>=A{- |1,0>|1,0> + |1,1>|1,-1> + |1,-1>|1,1>} but I can't see how to get an equation to solve for A (1/sqrt(3) in this case).
 
Of course
Currently in a PDE lecture, so I should probably pay attention :P
 
Anonymous
@0celóñe7 That's great. Good luck :D
 
@EdinburghDruid It's just normalization - with that value of $A$ the state has a norm of 1.
 
Thanks! Spent way too long looking at it
 
4:24 PM
Hello everyone
 
0
Q: Is it possible to receive reputation points on meta?

Erez ZrihenIs it possible to receive reputation points on meta? I have asked 1 question, which got upvoted, but before asking it I had 101 reputations. After the upvote I still see 101 reputations. I know that every upvote gives you another 5 reputations, so I should have 106 reputations, but not 101. Is t...

 
I need some help.
 
@PrittBalagopal What ails you? :P
 
I'm looking for good videos that can explain the circular fringes (Newton's rings) due to interference of light.
 
No idea, Have you tried youtube?
 
4:25 PM
I just joined college, and already they're killing me with an experiment to which I have not the vaguest idea about it.
 
@PrittBalagopal What is the experiment?
 
@PrathyushPoduval Yes I did, but most of them are indian. Although I am an Indian too, I find Indian videos to be too "bookish" and hard to learn the actual concept.
@PrathyushPoduval The Newton's rings one.
 
Sorry, I don't know of any good source
 
Anonymous
@PrittBalagopal Did you look at Physics Galaxy ? They did explain the concept well. You might be confused by interference of reflected light and transmitted light at first. Farcher on Physics Stack Exchange (main site) helped me a lot regarding that.
 
Anonymous
Newton's rings is a phenomenon in which an interference pattern is created by the reflection of light between two surfaces—a spherical surface and an adjacent touching flat surface. It is named for Isaac Newton, who first studied the effect in 1717. When viewed with monochromatic light, Newton's rings appear as a series of concentric, alternating bright and dark rings centered at the point of contact between the two surfaces. When viewed with white light, it forms a concentric ring pattern of rainbow colors, because the different wavelengths of light interfere at different thicknesses of the air...
 
Anonymous
4:32 PM
Wikipedia and the links given therein are also helpful.
 
Great thanks @Blue, I'll check those out
 
@PrittBalagopal May I ask why you are looking for videos specifically and not texts?
 
Anonymous
It's a pity that Farcher and Floris don't visit the chat :/
 
Anonymous
@PrittBalagopal Let me know if you have any confusion after watching those videos.
 
@ACuriousMind I'd like texts too, but I have a practical tomorrow (curse my institute for not explaining the concept), and I need to see a practical view of what's happening.
@Blue Physics Galaxy doesn't sound so good. It's basically just text translated into a video. I need an actual setup of the experiment, to see the phenomenon in it's true form.
 
4:38 PM
I didn't watch it entirely
 
Anonymous
@PrittBalagopal If you understand what's happening then setting up the experiment isn't difficult at all. I'm sure that you didn't watch the full playlist. You need to watch the videos in order to understand.
 
Anonymous
Tbh these things should be taught in high school. Perhaps that is why your institute didn't explain it to you.
 
Anonymous
If you don't have time then watch from video 39
 
Anonymous
 
Anonymous
The setup is trivial.
 
4:43 PM
Hi, everybody.
 
Anonymous
Hi @DanielSank
 
Yeah, they explained Young's double slit to us, but they didn't do this one.
 
Anonymous
If you understood YDSE then you'll get this too. :) It's just interference!
 
> Yime-dependent Schrödinger equation
:-P
 
Anonymous
@AccidentalFourierTransform urbandictionary.com/define.php?term=yime
 
Anonymous
4:51 PM
:P
 
Anonymous
"a weirdo stalker with greasy sunglasses." XD
 
rob
@0celóñe7 That's no trouble at all
 
@rob if you follow my discussion with ACM, I'm trying to explain the GR background on the poster, but it seems completely untenable
 
Some weird path integral-ish thingy in math chat
in Mathematics, 1 hour ago, by Kanishk
$$f(x)= \lim_{n\to \infty}\int_0^{f(x_0)} \tan\int_1^{f(x_1)} \tan \int_2^{f(x_2)}tan \int_3^{f(x_3)}\dots\int_n^{f(x_n)}\tan(f(x_n))\,dx_n\,dx_{n-1}\dots dx_0$$
 
4:55 PM
@Secret ew, why?
 
No idea, probably this user is doing some kind of real analysis thingy
It seemed to be some kind of countably infinite interated tan of an integral
 
@PrittBalagopal You can look up interference due to division of amplitude
 
What even is the Frechet derivative of this thing
 
rob
@0celóñe7 I think that what you have so far looks reasonable.
 
Can anyone refer a book for computational physics in Python language? I found the book by Mark Newman quite useful. So is there a similar kind of book? Actually, I used Newman PDF and it only contains 4 chapters. So I'm looking for another book which is similar to it
 
5:13 PM
-1
Q: Thanks for the feedback! Votes cast by those with less than 125 reputation are recorded, but do not change the publicly displayed post score

Erez ZrihenYeah but you can't get reputations in this website at all, so as a result I always have 101 reputations and 101 < 125, so I won't ever be able to downvote, but no way I see that others do this so what's going on?

 
5:27 PM
@rob sitting in an Efremenko class. You know him?
 
rob
5:43 PM
@0celóñe7 I do. A nice guy.
 
6:24 PM
-2
Q: Why on Physics meta you neither receive nor lose reputations but on meta stack exchange you do?

Erez ZrihenWhy on Physics meta you neither receive nor lose reputations but on meta stack exchange you do? On Physics meta: When someone either upvotes or downvotes one of your questions or answers then your number of reputations is unaffected. But on meta stack exchange: When someone upvotes one of you...

dude is obsessed
 
@rob I have to at least decrease the font, this is getting cluttered
 
new avatar? I dont like it
 
-2
Q: What shall I do if I am both question and answer banned and all my bad questions in physics stack exchange can't be improved?

Erez ZrihenWhat shall I do if I am both question and answer banned and all my bad questions in physics stack exchange can't be improved?

-2
Q: Why on Physics meta you neither receive nor lose reputations but on meta stack exchange you do?

Erez ZrihenWhy on Physics meta you neither receive nor lose reputations but on meta stack exchange you do? On Physics meta: When someone either upvotes or downvotes one of your questions or answers then your number of reputations is unaffected. But on meta stack exchange: When someone upvotes one of you...

 
@AccidentalFourierTransform did you like the previous one?
 
6:33 PM
@JohnRennie does this seem reasonable? i.gyazo.com/72c2f2dd1533b14fe769057f76f37ade.png
 
$M$ is both the manifold and the mass
use $\mathcal M$ for the former
or $m_B$ for the latter
 
Hello can i ask some assignment question here?
or exercises
 
also, you can remove the (classically written as $\mathrm ds^2$)
it is kinda superfluous
and you can save one line
@DonThomasReyes sure
 
@AccidentalFourierTransform I thought I did remove that
Oops
@AccidentalFourierTransform good point, thanks
I'll use mathscr for manifolds
 
Oh ok thank you.
 
6:41 PM
$\mathcal M\ge \mathscr M$
the first one is classy
the second one is drunk
 
Drunk on good Kentucky bourbon.
 
go home manifold, you can hardly stay on your feet
 
A 0.3 kg mass hangs at the end of a string. A second string hangs from the bottom of that mass and supports a 0.9 kg mas. (a) Find the tension in each string when the masses are accelerating upward at 0.700 m/s^2. (b) Find the tension in each string when the acceleration is 0.700 m/s^2 downward.
I tried to solve (a) for first box my formula is T=m1(a) + W ; wherein W=(m1+m2)g ? Did i did it correctly?
 
7:33 PM
@AccidentalFourierTransform mathfrak
 
7:44 PM
$(\mathfrak M,g)$
 
oh_no_god_no.gif
 
Hi, everybody.
Someone give me an interesting physics question.
I wanna feel useful.
Maybe a noise related question?
 
Ok
 
Or even something quantum.
 
Can you explain to me the God particle?
It's also called the Shog
 
7:55 PM
No.
 
if that helps
 
I wouldn't touch that with a ten foot pole.
Shog and 7SidedDie scare me.
 
Poor Shog :(
 
@DanielSank how would I model the elastic collision of two point particles in full GR
 
7SidedDie?
 
7:55 PM
@0celóñe7 Not a clue. Next.
 
Another name I haven't heard of
 
@Phase another evil
likely here already
 
so, are you gonna upload the hangout to youtube or not? ;-P
 
Btw
Why did you change your name to that mess of accents @0celóñe7
 
@AccidentalFourierTransform Calmate.
 
7:58 PM
@Phase a bet
 
jeez
@AccidentalFourierTransform it's already uploaded to Google Drive.
I'm listening to it. There's an echo :-)
 
for a second there I was wondering whether "calmate" was actually an English word
 

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