Anonymous
4:01 PM
@EmilioPisanty Well, I was thinking of some ways to publicize those tags via social media or community ads. I haven't yet thought out a structure for those tags though.

Anonymous
I don't know if that would solve the problem

@Blue By all means publicize via social media
but how on Earth would community ads help?

@Xasel I'm not creative:(

I maynot be experienced as you guys but I think that most of the physcist in 'niche' area may either don't get enough time or don't find incentive in participating in QA,maybe that's the cause of problem?

Anonymous
@EmilioPisanty Well if some knowledgeable people (in certain areas related to those tags) do happen to visit the site once in while they would come to know that we need more answerers/experts for those tags

4:03 PM
@ShaVuklia don't let Xasel fool you, there are indeed some books that are unfindable as free pdfs
@Blue that's traffic that's already on the site.
if they're interested in CM, odds are that they're already looking at the lists you want them to be looking at.

(or, if you're going to argue otherwise, do provide evidence)

@ShaVuklia that doesn't look amazingly safe to me

@ShaVuklia: P2P networks?....i found many books on torrents(ofcourse they are old enough to be legal)

4:05 PM
@BalarkaSen dude, that was so minimal, I didn't even realize when it began/ended lol.

@ShaVuklia what browser are you using?

@ShaVuklia Do you want someone else to risk their computer for you? :P We don't have magical tools to tell what's safe, either.

@ShaVuklia hi again whats new living on the wild side there? which reminds me, so whats amsterdam like anyway? :)

Anonymous
@EmilioPisanty I don't have any hard evidence. We have to try it out to check if it works. If we don't see any improvement we can just remove those ads anytime.

@EmilioPisanty firefox

4:06 PM
@Avantgarde Yeah? It's still pretty good

@vzn hi, and lol, what wild side:P I think the only 'wild' thing I've done so far this week is trying to get my books illegally :P without success

@ShaVuklia here's a handy tip: right click on the download button and click "Inspect element"

but Amsterdam is pretty cool

then tell me if that actually looks like a button to you

@Blue You have to consider that a) someone has to design these ads and b) if they do nothing, they take ad time away from others who actually do advertise something people didn't already know about
Since the ads are only shown on the site, I think it's pointless to advertise specific tags - everyone who will see the ad and is interested enough in the topic to click it will already watch that tag, anyway.

4:08 PM
@EmilioPisanty I have no idea, but I'm guessing it's not

@BalarkaSen wait, let me put it back on :P

@ShaVuklia well, do the same with some actual buttons out there and see what they look like

Anonymous
@ACuriousMind That's one point of view. Yes. I can't disagree

Does Bernardo still hang out here?

@ShaVuklia have you ever been to the red light district? know someone who has... wondering... o_O

4:09 PM
@vzn lol yea, I have
because it's literally in the centre of the city
it's quite impossible not to have passed it

@Blue so... you don't have any evidence that there's a problem, and, if there was, you don't have any evidence that running ads would solve it, but you still want the community to agree with you that we should take ad time away (from things the community has agreed are worth advertising) to favour the one tag that you've cherry-picked as maybe having a problem?

@ShaVuklia ah guessing its more tame during day? have you seen it at nite? any reactions/ opinions esp from the "yin side"?

@BalarkaSen Now I see the appeal

@vzn yea I have. last year I had to work at a caffee till midnight, and then I got lost in the red light district :P

@Avantgarde :) I was actually kind of dumbstruck on first listen because it ended so quick
But then I ended up listening to it 20 times :P

4:11 PM
the general atmosphere is quite negative and weird, if you ask me

@ShaVuklia @BernardoMeurer was here not long ago by transcript but havent seen him chat for awhile. hes in santa barbara with DS at a new college!

haha yeah some tracks leave you unsatisfied

@ShaVuklia "caffee"? coffee? re district, it is world famous, understand what youre saying

oh I meant cafe :P

@BalarkaSen I'm sure you'll like this youtu.be/9v9-Nw4nAZg

4:13 PM
@ShaVuklia work as employee or on your homework?

as an employee
it was just a summer job

thinking about Sha serving me coffee now, would defn visit your cafe for some coffee :)

Anonymous
@EmilioPisanty I had a feeling that there is a problem from my personal experience. But the last 1 year statistics does tell a different story. I don't know what to say. If no else feels there is a problem (and I am not saying that they should) it's fine. I don't want to quarrel. It was just a friendly suggestion from my side.

@ShaVuklia Occasionally but he hasn't been here as much as before since he moved to California

@ACuriousMind ah okay, thanks
@vzn and loll :P

4:16 PM
Aaaand this gem @Balarka youtu.be/cU8HrO7XuiE

@ShaVuklia wondering is that your real name or otherwise?

@Avantgarde Let me have a look
lol. "Refreshing Elevator Music"
That's like Music for Airports

@vzn It's not my real name, but I wish it was:P

@ShaVuklia ok, does it have some particular meaning?

4:18 PM
But that's just the name someone gave; whoever uploaded the video. I don't think that's the actual song name

ah lol
well "Music for Airports" was a real album name
also by Eno

Yeah I heard the part you gave me; was nice

@vzn not really. Sha was just short for Shadow (Shadow isn't always considered an acceptable name, but Sha is), and Vuklia is kind of a play on "vuk", which means wolf in Bosnian

Just to mention that if any user wants to explore or contribute or have discussion on Dynamical Systems,Non Linear Dynamics and Chaos then there is a chat room dedicated to this,although I admit that the room is not so active.

@ShaVuklia wolf eh? o_O cool do you have bosnian bkg?

4:21 PM
It would be nice if someone stars it so that other users who visit this room may notice it!

@vzn haha yea I do, my parents are from Bosnia

@BalarkaSen I thought I was about to get rickroll'd. But then, I was wrong. So wrong

sandstorm'd
daru'd

@ShaVuklia must say think math+physics great choice, do your parents have some bkg in those areas?

4:24 PM
@Balarka If you like exploring music (sorry, I don't know minimal, really) then this is your goldmine - bandcamp.com/tag/minimal

@vzn haha it is:) and no, they both did something in art! but they're both "analytically minded", if that makes sense, so I can get where I get my appreciation for math from :P
you do like computer stuff right?
do they also teach you incredible ways to get your uni books? :P

@ShaVuklia yeah deep into CS from young age myself... was musing it was around the time of the prior US eclipse :)

Hello,is anybody here?

@Avantgarde Huh, thanks a bunch. That does seem like a goldmine.

@ShaVuklia alas that is a worldwide challenge. my suggestion is to look for equivalent (free/ open) content on the particular subj/ topic youre trying to learn, which is now pretty large/ vast... eg opencourseware etc

4:27 PM
The way I usually go about music is I find people who collaborated with musicians I like, and then I go off on their works :P
And so on

@Sweeper Hello :)

I have a question,when doing electroststic shielding,do you need to shield just the line of sight or does the electric field go around obstacles ( copper shielding )

@BalarkaSen why do people write $\land$ for min and $\lor$ for max

@BalarkaSen People who collaborated? You know musicians, personally?

@vzn hm, equivalent material. I don't feel confident enough yet with the subjects to do that:P I guess I'll just buy it

4:30 PM
@Avantgarde lol, no, I just mean eg I got to know about Eno because he did a collaboration with Bowie

@BalarkaSen It's the best site for underground, semi-underground music of all genres. Free listening till eternity.
@BalarkaSen Ah yeah, same here

@ShaVuklia one can usually find ok condition used copies for more reasonable amts.

@vzn yea that's true

I asked this 16 hours ago,nobody replied,if you know physics / electronics,pls help physics.stackexchange.com/questions/355686/…

@ShaVuklia the content tends to be pretty stdized at undergrad level.

4:35 PM
@vzn are you saying that undergrads get more STDs than grad students?

@Sweeper The field goes around the obstacle. Blocking the line of sight is not enough

lol

@vzn yea that's true, but I can usually judge an equivalent book only after I've worked myself through a part of the course
or I don't know

@0ßelö7 sounds kinda nihilistic to me :P

maybe I should take that step

4:36 PM
@vzn You don't know what that word means

And magnetic field goes around obstacle ( MuMetal ) too?

@0ßelö7 lol and how do you know that

@Balarka Do you like rap? Pls no Jake Paul
The good stuff

@ShaVuklia are you looking for physics or math books or both? btw usually the TOC is free & reveal a lot about coverage/ content

ITS EVERYDAY BRO
WITH THE DISNEY CHANNEL FLOW

4:37 PM
WITHOUT*

LET ME EDUCATE YA AND I AINT TALKIN BOOK

@Sweeper Please be patient - SE is not designed for instant response and 16 hours is a pretty short timespan. However, your question is a bit unclear - you ask "is it enough" but you don't really specify what you want to achieve.

@Avantgarde You know, I have never felt great appreciation for that stuff. I have listened to some, but most often it's so centered around the rapper's personal life, neighborhood, thug life, money and fame that I don't get it. I like abstract hip hops, eg Madvillainy or the first mixtape of Death Grips (unironically, not memetically).

@Avantgarde why the JP hate

But no, not really

4:39 PM
@Sweeper Yes. In source-free regions of space the same mathematical equation describes both (Laplace equation), so the answer would be the same

@BalarkaSen I think people who unironically like DG are just trying to impress the melon man

looool

@BalarkaSen Madvillain and Death Grips? Good, you're almost there. :)

I honestly think most of DG is meme material, but Exmillitary is really good

@0ßelö7 I hate him everyday bro

4:41 PM
@Avantgarde Well the army dabs on you, h8r

I thought it was self explanatory,I want to shield object A from charged object B,I want to block the electrostatic field with copper

@BalarkaSen "so centered around the rappers personal life" lol

@dmckee Ok I talked to his grad student and he calls him by his first name

@Balarka youtu.be/yQ8sWcW-g_4 Something like Death Grips, but better

4:43 PM
I'm getting instant cancers from that .gif

I wonder if I must put the shield all around object A,or if its enough to put it only in the direct line of sight between object A and charged object B

@Avantgarde lol drill noises

@BalarkaSen Not your style? They're one of the biggest players in underground (experimental) rap for some time now

@Sweeper all around the object to shield it completely.

hates taylor swift... because she wont call me back @#%&

4:45 PM
I'm listening to it. I haven't heard of them before
I liked the drill noises immediately

@vzn She knew you were trouble
@BalarkaSen Almost all their albums are filled with such things. This is the fusion of industrial and rap

definitely TROUBLE :P

Damn, this is musically rich

look what you made me do... o_O

Glad you like it. Their albums are rich, yes

4:48 PM
Are you sure you arent mistaking electromagnetic field ( photons ) with static electric field? Becose I know when doing radio frequency shielding that you indeed must totaly cover the object to shield it,I was thinking that static electric charge would be differrnt

Death grips is the best band to dance to
just consult Youtube and you'll see

@vzn too many haters

@Avantgarde Ok, I definitely need to check more of Dalek's stuff out

@BalarkaSen Go ahead. The album from which that song was taken - youtu.be/mQQZi-MhF7Q

stays out too late, got nothing in my brain... cuz the players gonna play, play, play, play, play

4:53 PM
@lılostafa That's a weird ass dab

@BalarkaSen What's an ass dab?

tfw misplaced hyphen

I think a few years down the line, you might like drone. @Balarka It's a weird (and interesting) form of music

@Avantgarde I bookmarked that album. Thanks.

Have fun

writing "by the spectral theorem" should be a capital offense

@Avantgarde Is that what Sun O))) is onto?

What about if you use quotation marks

@BalarkaSen Yep! You've heard them?

Yup. Did a collaboration with Scott Walker very recently :P
"Soused"

5:00 PM
@0ßelö7 I just had four hours in our simulator. You would have liked that. One of the most expensive computer games in the world. ;-)

I haven't heard any of their music though. I plan to.

@lılostafa its sort of like white girl rap :P

@BalarkaSen Aah. I didn't know. Even I am not that big into drone (yet). But if you like minimalistic, repetitive sounds, then this is what you're looking for

Got it.

By the way, before I go, I found the album I should've given you quite some time ago. Minimalistic, atmospheric and probably the best album to sleep to - https://youtu.be/YSwIahX6t6I
(with the most beautiful cover art)

5:02 PM
@Sweeper Assuming time-harmonic fields, if the wavelength is much smaller than the length scale of the object, then you can assume very little diffraction where a line of sight obstacle is enough to shield the object. As you lower the frequency (bigger wavelengths) diffraction around the edges becomes more significant. (And therefore at the static frequencies non line-of-sight effects are important too)

@Avantgarde Oh damn Ulver. Thanks a ton.

where the hell is yugibb
or yuggib or however you spell his name
@yuggib where u at

@BalarkaSen Enjoy, and see you

Bye

Tay Tay!!

@AccidentalFourierTransform this tay?
@SwiftOnSecurity, Cyber, USA
Make stupid jokes, talk systems security, https://t.co/j3RdEScp3t + https://t.co/rzDVLlLn6y, write Scifi, sysadmin, and use Oxford commas. Sprezzatura.they/them
73.2k tweets, 197k followers, following 7.2k users

who dat
pretty awesome tbh

@AccidentalFourierTransform she was excellent at the start, now it's maybe a bit full of random twitter administrativae
"We were the victim of a very simple attack. It was through management's lack of focus on security that this happened." - no company ever
Security zen: If the NSA is after you you're already boned. Start worrying about actual threats, like Estonian teenagers with exploit kits.
Cheer up, at least China didn't hack where we keep our darkest secrets — Facebook.
^ lolz
and yeah, that is actual-Taylor-Swift's infosec twitter account

@yuggib I have a real Hilb sp. $\mathscr H$ and $H\ge 0$ is self-adjoint. I define $H^{1/2}$ using the functional calculus. Given $u\in D(H^{1/2})$ I want a sequence $(u_n)\subset D(H)$ such that $u_n \to u$ and $$\langle H^{1/2}u_n,H^{1/2}u_n\rangle\to \langle H^{1/2}u,H^{1/2}u\rangle.$$ This supposedly follows from "the spectral theorem" but I don't see what they mean

5:24 PM
https://t.co/HmXHIMd4Hb

@EmilioPisanty I have a question about QM but I'm not even sure how to formulate it properly
perhaps you could help me with that

@AccidentalFourierTransform maybe

so let's say I have two commuting operators $A,B$ that I diagonalise simultaneously
$A|a,b\rangle=a|a,b\rangle$ and similarly for $B$
and I have a third operator $C$. I'd like to know under what conditions I can write, for example, $\langle a,b|C|a',b'\rangle=\langle a|C|a'\rangle\langle b|b'\rangle$
for example, in the case of the hydrogen atom
I diagonalise $H,\vec L^2,L^z$

@AccidentalFourierTransform wait, what?

such that the eigenbasis is $|n,\ell,m\rangle$

5:30 PM
simultaneous diagonalizability doesn't imply a tensor-product structure

yeah, precisely
but sometimes it does
bear with me
back to the hydrogen atom
in this case, I know that for example $\langle n,\ell,m|L^x|n',\ell',m'\rangle=\langle n|n'\rangle\langle \ell,m|L^x|\ell',m'\rangle$
so in this particular case, the states factorise

ok, gotcha

I'd like to know whether this is a coincidence of this particular problem

well, this particular problem is pretty weird, no?
because it isn't a straight tensor product

or there is some property about the set $\{H,\vec L^2,L^z\}$, and the operator $L^x$, such that the matrix elements factorise

5:32 PM
it's a direct sum of tensor products of different dimension
(?)

well, that's kinda my question
I wanted to ask it on main, but I'm not even sure it makes sense, or how to formulate it clearly

@AccidentalFourierTransform well, $L_x$ commutes with $H$ and $L^2$

yeah, that seems to be relevant
but if we consider four arbitrary operators
$A,B,C,D$, and simultaneously diagonalise $A,B,C$

@AccidentalFourierTransform why four?
you only need three, no?

can we say that the matrix elements of $D$ factorise if and only if $D$ commutes with, say, $A$?

5:34 PM
just pretend that $H$ and $L^2$ are one operator
@AccidentalFourierTransform I would tend to say yes

as in $\langle a,b,c|D|a',b',c'\rangle=\langle a|D|a'\rangle\langle b,c,d|b',c',d'\rangle$

but drop the fourth operator
unnecessary
just $A,B,C$, with $[A,B]=0=[A,C]$

lol right, I dont want no d

then you know that A and B have a simultaneous eigenstate
call that one $v$

hmm so $[A,B]=[A,C]=0$ implies that $\langle a,b|C|a',b'\rangle=\langle a|a'\rangle\langle b|C|b'\rangle$?
I guess it does

5:36 PM
@AccidentalFourierTransform I should think it does

ok, so next level

I would look at the closure of the span of $\{v,Cv, C^2v, \ldots\}$
you know they're all eigenstates of $A$

Hi to all. I have a question/reference request : if anyone has any idea it will be helpful. In describing the transformation properties of the pions in chiral perturbation theory we demand that the goldstone fields of the pions transform non linearly under the hole symmetry group, let's call it G. The spontaneous symmetry breaking implies that the goldstones-pions transform linearly under the unbroken group, let' s say H, which is a sub-group of G... continue

so diagonalize $B$ in that subspace

the problem Im actually studying seems to suggest that, under some conditions, we have $\langle a,b|C|a',b'\rangle=\langle a|C_1|a'\rangle\langle b|C_2|b'\rangle$
but Im lost
because my $C$ does not seem to be a tensor product
so I have no idea what's going on

5:38 PM
huh
how complex is your $C$?

I don't have $[A,C]=[B,C]=0$, but the commutators are kinda simple
they are proportional to $C$
@EmilioPisanty as complex as it gets :-P
not really, but I'm not sure how to describe it here
I'd need to reduce it to a minimal working example
because most of its properties are irrelevant here

@AccidentalFourierTransform that'd help a good bit

yeah I'll think about it and report back
thx 😘😘

@AccidentalFourierTransform a'ight

@dmckee I have to agree, unfortunately; I've seen it elsewhere.

5:44 PM
omg, Imperial, this is so dumb
good job there

there is a penis joke somewhere there

Hi to all. I have a question/reference request : if anyone has any idea it will be helpful. In describing the transformation properties of the pions in chiral perturbation theory we demand that the goldstone fields of the pions transform non linearly under the hole symmetry group, let's call it G. The spontaneous symmetry breaking implies that the goldstones-pions transform linearly under the unbroken group, let' s say H, which is a sub-group of G... continue
Then the argument goes as follows: the pions should transform under the action of G by a function f(g, pions) such that this f(g,0) lives in the quotient space G/H and thus the function f maps the the elements of the quotient space to the pion field variables, and the function is obtained by G by right multiplication of the unbroken subgroup: g'=hg. So geometrically the pion fields may be viewed as the coordinates of the quotiend space G/H . continue
So, to understand the hole subject mathematically I need to understand the mathematics of quotient spaces as used in physics and why this is relevant to the gepmetry of the pions. Any references or suggestions? Thanks.

last time I posted that "hole" meme I was suspended
will I do it again?
must... resist... the temptation...

@AccidentalFourierTransform what is a "hole" meme? and why it got you suspended

yesterday, by AccidentalFourierTransform
Im not posting it again :-P
you have the url there
type it yourself if you really want to

5:55 PM
@ConstantineBlack I think "mathematics of quotient spaces" is a bit vague. I think you're simply looking for references on spontaneous symmetry breaking, no?

perhaps a reference on SSB for the mathematically inclined student?

@AccidentalFourierTransform python apparently grows so fast it's not even subject to the regular ebb and flow over the summer and winter breaks

gurl wanna see a python grow?

@AccidentalFourierTransform is that a goatse link? 'coz that would definitely get you suspended

http://s2.quickmeme.com/img/43/430ae8a1dccb618e3a2ed57fa412fb9558dc13a49630bc9b‌​7f18a1042215da45.jpg
see for yourself

5:59 PM
@ACuriousMind Well, maybe, if they have a detailed discussion about the use of a quotient space so I can read why this certain transformation f fixes the transormation properties uniquely(by discussion I mean something more than a statement of the form: the mapping f fixes the properties of the pions per se).
Lewtwyler discusses this in Principles of Chiral Perturbation Theory and the standard mathematical paper is of Weinberg on Phenomenological Lagrangian but that paper takes to much mathematical knowledge(for me I mean) as granted so it' s a bit difficult to follow.

@AccidentalFourierTransform 404?
killer meme, yeah

404 wtf