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00:00 - 15:0015:00 - 00:00

12:44 AM
been a while since i saw you online @0celo7
 
@user507974 someone decided to ban me for a month
 
wahhhhh?
what was the reason
 
lack of intelligence
 
@DanielSank what we were talking about
@0celo7 so basically just because they're an asshole? What was the context?
 
@ACuriousMind I couldn't find chocolate pudding :(
I did get a beer though
and chocolate cookies
 
12:50 AM
@user507974 yes, don't know
 
@BernardMeurer beer dipped cookies?
 
@user507974 I got a Delirium Tremens, I ain't heretic to do that
 
@0celo7 dont they have to at least say where the infraction came from
 
@user507974 no
 
@user507974 That's something you'd do to Faxe
 
12:52 AM
well, glad to know that were one bad mod away from a dictatorship
 
away?
 
it doesnt list who did the banning either?
 
bro it's fucking 4th reich in here
@user507974 I know who it was
no need to incur his wrath tho
 
no need to list since i bet theyll go asshat
if you dont hear from me its 50/50 ive incurred the unknown persons wrath
 
@user507974 Don't provoke the mods, they don't take it lightly :v
 
12:54 AM
yea
i was theorizing summer vacation was why you werent around though ocy
alas, it was more insidious
 
I was on vacation
 
@0celo7 are you doing your research in the lab this summer?
 
yes
 
cool, and do you have any classes as well?
 
yes
 
1:00 AM
which classes will you be doing?
 
what research?
 
@0celo7 How's bob?
 
@BernardMeurer He spilled coffee all over me today
 
who's bob?
 
@0celo7 Lol
@0celo7 Karma
Is michelle there too?
 
1:06 AM
no
 
Ah, that explains it
 
@BernardMeurer drinking age...
 
@BernardMeurer is there one near waterloo?
 
@0celo7 19 dawg I'm almost there
@3075 They're all over as it seems
@3075 Yep, two near Waterloo
 
cool.
for some reason beer doesn't appeal to me.
 
1:12 AM
@3075 It grew onto me after I started having good beer every once in a while
chugging cheap ass beer isn't all that good
except one you're sad, then it's awesome
 
beer is not good
 
but it doesn't even taste good.
i'd rather have iced tea.
 
...what
 
what?
 
@3075 Some do (Delirium) some don't (Berliner Kindl, Faxe,...)
@3075 And beer is a lot about finding which one you like, because an indian pale ale, a belgian strong ale and a lager are entirely different beverages taste-wise
@0celo7 You're German, you're not allowed to say that
 
1:16 AM
IPA is literally the worst drink
 
@0celo7 IPA's are alright, they're not my favorites
 
anyone who likes them unironically has a brain tumor
 
@0celo7 Or they have balls unlike you
 
@BernardMeurer sigh
I don't know why you're such a dick lately
 
@0celo7 :)
@0celo7 It's because I've grown to like you
 
1:20 AM
gayyy
 
Much like IPAs
 
Zelda is such a terrible character in the new smash
 
reminds me did you hear they're making a new cod4
it will be really cooooool.
 
COD is crap dude
 
shooters are crap
 
1:24 AM
:'(
 
BF is alright
 
1:44 AM
@0celo7 can you recommend any clean rap music?
 
@3075 Go listen to classic dawg
 
classic?
 
Classical music yeah
 
all classical music sounds the same to me.
 
Or well, it doesn't have to be classical, just orchestral
@3075 You just haven't been converted yet
I'll do some clockworked orange training to you if I get to Waterloo lol
Meh, people oversold me this beer
it's good
but it's not what i thought it was
 
1:49 AM
@3075 no
 
@BernardMeurer did they say tomorrow is the last day for admissions at waterloo?
because it is for canadians.
 
@3075 Nope
 
@3075 why would you even want clean rap
it's like dirty bible music
doesn't make sense
 
are you implying all real rap is dirty?
 
@3075 of course it does
 
2:04 AM
@AlfredCentauri is that sarcasm?
or are you agreeing?
 
2:34 AM
@3075 Let there be no mistake, I am agreeing that all classical music sounds the same... to you.
 
@3075 yes
 
@AlfredCentauri Classical is amazing
 
@vzn Every little discovery we make the news are like "COMPLETE BREAKTHROUGH, UNDERSTANDING OF THE UNIVERSE COMPLETELY CHANGED"
 
vzn
@BernardMeurer "BF"? nice xkcd =D
 
2:46 AM
And I'm always like, chill dude they just discovered that Raccoons will beat Chihuahuas in a fight
@vzn Battlefield :)
 
vzn
@BernardMeurer yeah, but there are some really big new findings lately/ last few yrs. higgs, gravity waves/ black holes, QM weak measurement etc... have said its a golden age for physics.
 
@vzn The golden age has been going on since the beginning of the 20th century :p
 
vzn
@BernardMeurer true, but physics seemed to "solidify" for decades. oh yeah, nanotubes/ buckyballs are a big deal (but still very hard/ expensive to fabricate). lets see, superconductors also. bose-einstein condensate. it would be very cool to make a list. top physics hits.
 
Billboard top physics hits :p
 
vzn
@BernardMeurer ps know that feeling, but dont you have family/ friends?
 
2:50 AM
@vzn That's complicated. Don't like getting into my personal life, but my family isn't here
 
vzn
@BernardMeurer (ok) they are not in brazil?
 
@vzn They don't stay much in the house I live
 
vzn
sounds like you are getting closer to cs from recent comments?
 
@vzn I'm getting closer to physics actually
idk what I'll do with my life
 
vzn
when in doubt, hang out on a chat line :P
 
3:00 AM
@BernardMeurer Indeed; as a somewhat aged hard rocker, I do understand that power chords were not a 20th century innovation of hair bands. See, for example, about 9:20 into this: youtube.com/watch?v=4C3TIr2bBo0
 
@AlfredCentauri I love that piece, even though I'm not the biggest Beethoven fan. And that's light core, I can get you some hardcore classic if you want :p
Like this or this
 
3:15 AM
@BernardMeurer good lord, she's amazing; thanks!
 
3:31 AM
@AlfredCentauri yes, Lisitsa is an absolute goddess of virtuoso pieces
 
user116211
Morning folks.
 
@MAFIA36790 o/
 
user116211
3:50 AM
@Bernard any recent news about your result?
 
@MAFIA36790 No, reason why I'm drinking daily :v
 
user116211
T__T
 
user116211
4:08 AM
the GREATEST intriguing String Theory problem here comes:
 
user116211
-1
Q: capacitance inside dielectric

A.BHATTACHARYYAtwo parallel plate capacitor separated by 2 mm,are at a potential difference of 20 v.A dielectric sheet of dielectric constant 2 and thickness 1 mm is inserted between the plates.How does the potential difference between the two plates change??

 
user116211
suffering severe heart attack
 
5:47 AM
**Aside:** Please don't close this. I have a genuine interest in studying the answers to this question. I understand that overwhelmingly, the shared belief is that one has to pick a text, read and compute everything. I don't even subscribe to the canonical media let alone method of study. I am not trying to be a maverick, I just can't learn like that, at least not right now. So please don't tell me to buy a book and solve the problems in it. I can't guarantee to be polite if you grill me over this.
@JohnRennie Just mentioned the geometric and cft cross ratios are not related
 
user116211
@kevinTahN. where did you get that?
 
are they related?
 
user116211
hmm.. nay ;/
 
so what is it in cft?
I seem to have been not even close
 
@kevinTahN. Have you googled for four point function?
 
5:51 AM
I am googling it right now
I am looking at this arxiv.org/pdf/1311.4546v1.pdf right now
It has a statement of the result. I should try to find something more elementary
yeah, lol I am a complete donkey when it comes to this
Can you help me reason what it is?
So I know what an n point function is from qft
the r's and deltas look strange
 
Jeez, people. Abstract pages! It is always better to link to the abstract page.
4
 
Noted :D
 
6:11 AM
@vzn it'll appear 7 days in advance of the event
Note that it'll be up to you, or someone you designate - I mean, not me - to run the interview portion of the chat session
 
6:26 AM
alright then, if anyone wants to walk me through this lmk . . . pm me or something. I am available close to 24/7 for this
 
What do mean "lmk" and "pm"?
 
lmk means let me know . . . I think pm means private message
 
Thank you:-)
 
hehe
:D
 
 
1 hour later…
7:44 AM
Hey
 
user116211
So, @Slereah, what do you like to be asked when you would be the guest?
 
Ask me if I have healthy bees
 
user116211
A Chinese or Japanese chef will throw the rice on the floor and make you do it again, if you add salt. Seriously, it's all about how you like it. There is absolutely no reason from a physical point of view to add salt. The boiling point won't go up that much, anyway. If that's what you want, then you need a pressure cooker. Rice in a pressure cooker will turn to mush. — CuriousOne 27 mins ago
 
user116211
Good one from CuriousOne.
 
user116211
@Slereah noted
 
7:49 AM
Or you know
Ask a question you may have on the topic I'm discussing
 
user116211
BTW, we should talk physics. (remembering JD)
 
user116211
@Slereah That would be relevant- noted
 
Sure
Currently I'm trying to think of a way to construct a manifold for intrauniverse wormhole
With a decent coordinate system
Don't think I'll manage to do it in one map, so current idea is
Cylinder with the usual coordinates $S^1 \times [0,1]$
And plane minus two disks in bipolar coordinates
Not sure if it is best to pick basic bipolar coordinates, two center bipolar coordinates or biangular coordinates
I think that's a good choice because the overlap will be easy to do
Basically the overlap is all polar coordinates
locally anyway
 
user116211
8:16 AM
How much curvature do you have? :-) — CuriousOne 3 mins ago
 
user116211
Is it helpful ;/
 
Depends on the booty
Hm
How do two-center bipolar coordinates work
Apparently they're only defined for $r_{1,2} > 0$
Wouldn't that only span the half plane
oh wait, do they have to be only positive
the sites aren't too clear
ah yes I guess $r \in \Bbb R$
It's a good coordinate system for what I have in mind, but on the other hand, I'll have to tinker some local polar coordinates if I want to do transition maps
Shouldn't be too hard really
I guess I need like
4 patches
bipolar for the plane, 2 polar around the foci, and the cylinder one
Then I just need to do the overlap of the cylinder and the polar patches
and the transition between bipolar and polar
All good
The hard part is figuring out how to solve PDEs on a manifold that is on different coordinate patches
Hello the @0celo7
Man there basically ain't shit on two center bipolar coordinates outside of what's on wikipedia
Hm, let's see, what's the metric tensor in biradial coordinates
$\frac{\partial x}{\partial r_{1}} = \frac{-r_1}{2a}$
$\frac{\partial x}{\partial r_{2}} = \frac{r_2}{2a}$
$$\frac{\partial y}{\partial r_{1}} = \pm 4 a \frac{-r_1}{\sqrt{16a^2r_2^2 - (r_2^2 - r_1^2 + 4a^2)^2}}$$
$$\frac{\partial y}{\partial r_{2}} = \pm 4 a \frac{(a^2 - 1) r_2}{\sqrt{16a^2r_2^2 - (r_2^2 - r_1^2 + 4a^2)^2}}$$
Not too trivial
Wait how do those coordinates even work
You can't have arbitrary values of $r_1$ and $r_2$
Yeah there's $r_1 + r_2 > c$
I think if $r_1$ is too big the coordinate transformation fucks up
 
9:42 AM
"This book is not about quantum field theory or anything like that, it is about curvilinear coordinate systems, how the Laplace and Helmholtz equations appear in each system, and what the solutions of these equations look like. This husband and wife team wrote several excellent books. Long ago they were strangely involved in an accident involving a test of general relativity. "
 
10:09 AM
@Slereah You are insane.
 
@0celo7 am I
 
@Slereah you're alternatively sane
 
It's just a coordinate system jeez
I think the usual bipolar coordinates would be best
Tho the transition to polar around the foci will be tougher
Since the isocoordinate circles around the foci aren't concentric
 
10:36 AM
Pretty good document but I feel like it was written with bloody Word
Hm, the intersection of isocoordinate curves in bipolar is always orthogonal
I think the transition between cylinder and plane should be smooth enough?
 
user116211
-1
Q: Electro megnatic field and ghost

yubraj sharmaWhat is electro megnatic field ? How and where it is generated ? I've heard that science doesn't believe in ghost. Is it true ? Is that emf what the science believe to be ghost. Please tell me. Thanks in advance

 
user116211
It's HAUNTED!!!
 
We all know that ghost fields for EM are not coupled to the EM field
I guess once I have the bloody coordinates I need to have $g(\partial B)$ equal on both coordinate patch
And the connection too
mb the Riemann tensor too, I dunno
Is there a theorem for non-simply connected non-compact surfaces and their metric
Can I have a flat metric on it
"Theorem. Le t(X1,g1) and (X2,g2) be any two manifolds, possibly with boundary, with complete metrics g1,g2 of constant scalar curvature n(n−1). Suppose also that the metrics gi satisfy the nondegeneracy condition (2.12) and either (2.15) or (2.16)–(2.17) below. Then for any points pi∈Xi, the connected sum X1#εX2 obtained by excising small ε-balls around the pi and identifying boundaries, carries a complete nondegenerate metric gε of constant scalar curvature n(n−1)"
Maybe I guess?
 
user116211
11:02 AM
1
Q: Why is U(1) the gauge group in classical electromagnetism?

BendyCan anyone give a physical reason that $U(1)$ is the gauge group for classical electromagnetism? I am familiar with the principal bundle formalism for Yang-Mills theory and see that since the Lie algebra of $U(1)$ is $\mathbb{R}$, the Yang-Mills equations reduce to Maxwell's equations. However, ...

 
user116211
That's an ideal question from a newbie; correctly formatted; proper research efforts showing well prior-research.
 
I think if I just leave both patches as flat manifolds the connected sum will also be flat
Possibly
 
user116211
@dmckee: since you posted there, i'm pinging you; OP is constantly removing the homework tag from her question although it is indeed homework; I rollbacked it but OP seems to be adamant.
 
Tho apparently there might be a tiny section with curvature at the joint
I dunno
I should check soon
When I have no job again
 
11:17 AM
@Slereah what theorem is that
 
and for flat manifolds
Thinking about it
Pretty sure what I have in mind wouldn't work
Otherwise I'd have a static vacuum wormhole
So it can't be flat
 
12:00 PM
What would be a good condition in a wormhole tho
Hm
Plane should be asymptotically flat, i guess
No horizon round the cylinder part
Path shorter by taking the cylinder than the plane, ideally
 
 
1 hour later…
user116211
1:18 PM
@AccidentalFourierTransform: o/
 
sup?
how are you doing?
 
user116211
@AccidentalFourierTransform Giving a shit with Jones Matrix calculus.
 
lol why would anyone do that?
 
user116211
@AccidentalFourierTransform Polaroids .... the most boring text I'm reading now Crawford's waves.
 
for fun? :P
youre in college, right?
 
user116211
1:23 PM
@AccidentalFourierTransform everything is for fun ;/
 
user116211
@AccidentalFourierTransform nay.
 
then I don't get it :/
optics suck
 
@ACuriousMind Why?
 
user116211
@AccidentalFourierTransform why ;_;
 
no way you like it?!
well I had a terrible professor, which might be related to my loathing
 
user116211
1:38 PM
@AccidentalFourierTransform Well don't hate it; but yeah not interesting; for past two days I'm indulged in these boring books and pdfs; I'm trying to get which is within my scope and skipping some nonsense experiments; yeah it sucks T__T
 
Hi everyone! Performing the Faddeev-Popov procedure, usually we say that we are "quantizing the gauge theory". I don't understand at which step we quantize something… what's the meaning? what's the point?
 
@ACuriousMind Uh, what?
To graduate in my county one has to write a research paper.
 
@FrancescoS no, the FP proc. "fixes the gauge". The theory is already "quantised".
 
@AccidentalFourierTransform are you a Brit
 
1:41 PM
The Faddeev Popov Spooky Ghost is just a Lagrangian way of expressing the identification of every gauge equivalent field
Otherwise, when doing path integrals, you're going to integrate on fields that are the same
 
@0celo7 a fake brit, yeah
 
@AccidentalFourierTransform aussie?
 
lol no, spain
 
Basically the ghost term is just a way to write a delta term into the Lagrangian
So that every gauge inequivalent field is only counted once
 
user116211
@AccidentalFourierTransform fake brit, hehehe.
 
1:44 PM
thanks ;)
 
its just that british accent sounds nicer to me
 
Obviously you've never heard a vulgar british accent
 
I spent some time in london when I was younger
 
@AccidentalFourierTransform you misspelled quantized
 
around a year or so
 
1:47 PM
@Slereah proof?
what even is a path integral
 
An integral
Over the paths
Proof is in Peskin
 
Peskin in a damn physics books
you know who reads physics books?
chemists
 
I'm sure you can find a fancy math proof somewhere
For BRST quantization
 
@Slereah "proof" heh
 
Or just do like everyone else and ask ACM
 
user116211
1:51 PM
@0celo7 o.O
 
vzn
hi @Slereah congratulations youre confirmed 16:00 UTC Tue Jun14th =D ... alas may not be available myself (will do my best to be there!) so ask you to lead it if not there. can come up with a list of questions/ topics together if you like, also with input of others, although we already brainstormed a bit about CTCs + interstellar etc.
2
 
Gee I hope not
Interstellar was pretty boring
 
vzn
@Slereah tell us why etc, the Physicist Experts opinion on movie etc :)
you mentioned you had some understanding of their visual rendering approach didnt you?
 
There really isn't any movie with even an attempt at a realistic time travel stuff
 
vzn
theres a cool wired article out on that.
 
1:54 PM
Oh yeah
It's just the standard raytracer for a black hole
 
vzn
@Slereah another great topic/ angle, hollywood vs real physics etc
 
which is totally different from the raytracing of a wormhole
 
vzn
@Slereah and ofc black holes are boring compared to CTCs right? :P
 
Well Kerr black holes have CTCs
 
vzn
DZ just said he can/ will put up a link on main page 7days advance... was hoping for even longer but its ok/ great :)
plz star the confirmation line earlier with boldface time :)
thx man
 
1:57 PM
Who's the guy that does the one on the 7th
 
vzn
@Slereah DZ asked us to give him lead time/ "warning" so its DZs regular meeting on 1st (it goes every 2 wks). he could mention the upcoming special guest.
 
user116211
@vzn: I still didn't get how we would take questions. Can I throw light on it a bit?
 
vzn
@MAFIA36790 fire away MAFIA. my idea for now is to not overthink it, just let the guest lead & decide the fmt. think just a free-for-all is acceptable, ideally not "distracting/ nonsequitur comments" by audience, all else ok. if its busy the guest may have to just pick questions from the stream (dont really foresee that right now except with very famous guests, even then maybe not likely, because dont think chat audience will be big.)
 
@vzn Will you be doing a presentation, too
 
vzn
@Slereah just want to organize/ coordinate this a bit for now, see whats possible, introduce guest if there, maybe ask a few questions if others dont, am willing to write up a blog page on what weve done so far, sought after guests, future directions etc if ppl really want it right away
anyway thx for everyones help/ feedback so far, realizing now this is not so easy to pull off (aka "herding cats" aspect), looks like it will happen now, it will be unprecedented, think its way cool, hope to build it up with continued cooperation/ good teamwork from all :)
Jun 1st oops sorry correction the next regular mtg is May 31
 
2:55 PM
Hi everyone, Is there an expansion for the exponential of a sum of two matrices that expands it in a serie of commutators of the two matrices? Kind of like an inverse of the BKH formula?
(Baker Campbell Hausdorff)
 
@ACuriousMind please name my rival in Yellow
 
@PhilipV Do you mean the Zassenhaus formula?
@0celo7 I'm not sure I can make such an important decision for you
 
@ACuriousMind I trust you
 
@0celo7 Then I dub him "Dude"
 
@ACuriousMind Yeah, Thanks. But that's going to be super messy...
 
2:59 PM
@ACuriousMind Oh I want a rapper theme
 
@0celo7 And you ask me for that?
I don't know any rappers
 
@ACuriousMind Yes.
@ACuriousMind Uh, use your Google fu?
 
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