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no_choice99
no_choice99
2:00 PM
ok
 
ACuriousMind
ACuriousMind
So we can't say that we should see expansion on this scale to begin with, even if there weren't the issue with bound systems.
 
no_choice99
no_choice99
ok
so space expansion is not homogeneous in the whole universe?
i.e. it varies according to whether there's matter or not
mass should i say
 
2017
2017
@JohnRennie How to apply the leading-lagging terminology for standing wave loops? Suppose we have standing wave $$y=10\sin(\frac{4\pi x}{5})\sin(10\pi t)$$ then do we say that first loop (from x=0) is lagging by "$\pi$" radians or leading by "$\pi$" radians w.r.t the second loop?
 
ACuriousMind
ACuriousMind
@no_choice99 Well, at large scales the galaxies are approximately distributed homogeneous and isotropic. The issue is not the presence of matter but its symmetry
On smaller scales, calculating the correct metric is infeasible
 
no_choice99
no_choice99
i didnt know that
 
ACuriousMind
ACuriousMind
2:02 PM
So it's not clear at all whether to expect to see expansion on our scales or not
 
no_choice99
no_choice99
acuriousmind what do you think of the landau's series to learn general physics
by general i mean all domains
 
ACuriousMind
ACuriousMind
Haven't read any of them, so I can't comment at all
 
no_choice99
no_choice99
ok
 
Qmechanic
Qmechanic
0
Q: Equations of constrained motion

Vasu GoyalWhen we solve a mechanics problem, we do it by forming constrained motion equations and at times we write the same equations again, is there any way to identify which all equations are unique and not just a manipulation of what we wrote previously?

newtonian-mechanics classical-mechanics
Unclear?
 
no_choice99
no_choice99
clear but should give at least 1 example
else, not precise enough
just my take on it
 
0celo7
0celo7
2:16 PM
ACM doesn't know how to read I'm afraid
 
no_choice99
no_choice99
go ahead 0celo7
are landau's books ok to study solid state
like vol 9 or 8 stat mech 2 whch deals with fermi liquids
 
0celo7
0celo7
Go ahead?
 
no_choice99
no_choice99
go ahead and reply to the question i asked you above ^^
 
0celo7
0celo7
I haven't read them.
 
no_choice99
no_choice99
thx then curious why you said ACM doesn;t know how to read
 
0celo7
0celo7
2:28 PM
Because he doesn't. No use asking him about books.
@ACuriousMind What's one good reason for not getting an X box one to play TW3
 
no_choice99
no_choice99
ok thanks 0celo
 
ACuriousMind
ACuriousMind
@0celo7 If you aren't interested in the greater diversity of PC games you could play, none really. TW3 plays better with a controller anyway, imo
 
0celo7
0celo7
@ACuriousMind I don't want to spend the money for a gaming PC
But I would miss my mods
(I'm at a store where they have X box ones)
 
AccidentalFourierTransform
AccidentalFourierTransform
buy a wii
 
0celo7
0celo7
2:44 PM
I have one
 
no_choice99
no_choice99
they say the new zelda is the best game in the last 20 years
 
AccidentalFourierTransform
AccidentalFourierTransform
no that's half life 3
 
no_choice99
no_choice99
300 people worked on it several years.
 
0celo7
0celo7
I'm not gonna buy a switch just for one game
 
no_choice99
no_choice99
maybe buy it used
dunno
 
0celo7
0celo7
2:46 PM
You can get used consoles that are 2 weeks old?
 
no_choice99
no_choice99
sure
some people buy it, finish the game in a few hours and then sell it
 
AccidentalFourierTransform
AccidentalFourierTransform
you could get used copies of no man sky the very next day after its release
 
no_choice99
no_choice99
hahahha that's understandable
 
0celo7
0celo7
I still don't know/understand what happened there.
What was wrong with the game?
 
AccidentalFourierTransform
AccidentalFourierTransform
no boobies
 
no_choice99
no_choice99
2:48 PM
apparently the programmers had ideas that they weren't able to make work. but no idea why they made a nice trailer that has nothing to do with the game
i mean i dont know how they made the trailer, it's not actual gameplay despite its look
nothing much wrong with the game. it's just that people expected much more
 
user129412
user129412
Does anyone know where to find the charge neutrality level (with respect to the top of the valence band or the bottom of the conduction band) for InSb? I was able to find it for InAs, but not for InSb. But if I remember correctly it's inside the band gap, maybe even close to the valence band (wheras InAs is inside the conduction band)
 
no_choice99
no_choice99
@user129412 there maybe ? researchgate.net/publication/…
 
user129412
user129412
@no_choice99 Interesting! Funny how for the one I am interested in their reported values are all over the place. Or well, from exactly on top of the valence band to a bit above. I guess that's something already.
 
no_choice99
no_choice99
no idea . i didnt know about charge neutrality level before you mentioned it
i gotta study some ashcroft and mermin i guess
 
user129412
user129412
3:04 PM
Yeah I still find it a rather tricky concept myself.
 
John Rennie
John Rennie
@2017 It doesn't matter what convention you use because the wave has a period of $2\pi$. As a general rule we keep phases to less than $\pi$ so you'd say the second wave was lagging by up to $\pi$ or leading by up to $\pi$. But that's not a hard and fast rule.
 
2017
2017
"As a general rule we keep phases to less than π so you'd say the second wave was lagging by up to π or leading by up to π"<---- We keep phases to less than $\pi$? Where? I didn't get that part...could you reframe it please?
@JohnRennie
Which phases do we keep to less than $\pi$?
 
0celo7
0celo7
@JohnRennie I once had to compute a phase for my physics homework. The calculated answer was like 2000 rad. I reported that mod 2pi and it was wrong.
 
2017
2017
And "second wave"? Isn't there only one standing wave here?
 
0celo7
0celo7
Because the TA didn't know if I had computed it using the method demonstrated in class.
 
John Rennie
John Rennie
3:11 PM
-2
Q: Crazy thought about black hole

Pranav ModiSuppose the body didn't get affected by any force and didn't collide so according to law of relativity the body achieved infinite mass and hence infinite gravitational force hence this maybe black hole.

black-holes
As question titles go that one is remarkably appropriate :-)
 
2017
2017
@0celo7 XD
reminds me of my school's physics teacher
@JohnRennie When you said "second wave" did you mean in a different situation when there are two waves?
 
John Rennie
John Rennie
@2017 yes, I didn't read your question properly - sorry :-(
 
2017
2017
np :)
 
John Rennie
John Rennie
I'm not sure what you mean by the phase of a standing wave ...
 
2017
2017
1
A: How to apply the leading-lagging terminology for standing wave loops?

FarcherThere is no right or wrong as to which motion is leading/lagging the adjacent loop. There is a $\pi $ phase difference and you can choose whatever term (lead/lag) you like in whatever order of mentioning the loops you like.

 
John Rennie
John Rennie
3:13 PM
The phase term is presumably just $10\pi t$
 
2017
2017
@JohnRennie I meant the phase difference between particles of two adjacent loops which differ by pi radians
I wanted to know if the particles of the first loop lags or leads w.r.t the second loop
 
John Rennie
John Rennie
Loops? You the part in between two nodes?
 
2017
2017
@JohnRennie On either side of a node
lemme upload a picture
 
John Rennie
John Rennie
That's OK. I think I understand.
 
2017
2017
oh okay
@Farcher says that the terminology of leading lagging won't apply here as there is no reference point
 
John Rennie
John Rennie
3:19 PM
Suppose you take a snapshot in time and graph $y(x)$, then the instantaneous graph is $y = A\sin(kx)$, where $k = 2\pi\lambda$. Yes?
 
2017
2017
@JohnRennie right
yes
 
Moses
Moses
Hi all
 
John Rennie
John Rennie
Sorry, I was distracted - I was buying a laptop on eBay :-)
This one. Don't tell Kaumudi! :-)
 
2017
2017
@JohnRennie Omg, buy a new house too, or else you won't have space left to live in your house :P It will be full of LAPTOPS!!!!
 
John Rennie
John Rennie
@2017 I plan to give this one to a friend - I won't be keeping it.
Anyway ...
To get to the second loop you move a distance $\lambda/2$ along the $x$ axis.
 
2017
2017
3:28 PM
@JohnRennie Ah, so you didn't go full crazy, yet! :)
@JohnRennie yep
 
Moses
Moses
Can I ask a quick QM question, in many text it gives the 3 dimensional eqigenvalue equation of say the position operator $$\hat{X} | \vec{x} \rangle =\vec{x} | \vec{x} \rangle .$$ So as I understand the $\vec{x}$ is the eigenvalue, hence a scalar, but it has three different components, since $| \vec{x} \rangle$ is simultanously the eigenstate for the three different components of the position operator $\hat{X}$, namely $\hat{X}_x, \hat{X}_y$ and $\hat{X}_z$.
 
John Rennie
John Rennie
So if you start at $x = 0$ you end up at $x = \lambda/2 = \pi/k$ so the phase relative to your starting point is $kx = \pi$.
 
Moses
Moses
So basically it's like a notation which contains three eigenvalue equations in one equation? Is this correct?
 
2017
2017
@JohnRennie right
yes, if you take x=0 to be starting point
 
John Rennie
John Rennie
So I'd say the second loop is $\pi$ ahead of the first loop.
 
2017
2017
3:31 PM
@JohnRennie why ahead?
 
John Rennie
John Rennie
Because you will have to wait a time $t = \tau/2$ for the first loop to reach the same position as the second loop is at $t=0$, and during that time the phase changes by $\pi$.
 
0x90
0x90
Hello everyone is it ok if I ask to turn your attention to a thing that bugs my mind for few weeks?
I am trying to understand how to calculate the angular momentum states for QM isotropic harmonic oscillator. I have 2 problems: I don't understand how I can exploit spherical tensors and how to jump between subspaces of angular momentum.
 
John Rennie
John Rennie
But mathematically leading by $\pi$ is exactly the same as trailing by $\pi$.
So use whatever convention you want.
 
2017
2017
@JohnRennie If you see the equation then you'll find that at t=0 the first loop particles is in exactly the same position as second loop particles...
All the particles will be at y=0
at t=0
I don't understand what you mean by wait for $\tau/2$
 
John Rennie
John Rennie
Really?
The velocities of the particles in the first loop are the same as the velocities of the corresponding particle in the second loop?
Not different by a factor of $-1$?
 
2017
2017
3:36 PM
$y=10\sin(\frac{4\pi x}{5})\sin(10\pi t)$
At t=0, y=0 for all particles in all the loops
Right, velocity will be different though
 
John Rennie
John Rennie
Yes, but even so the first and second loops aren't the same because the particles in them are moving in opposite directions.
 
2017
2017
@JohnRennie yes indeed...oh, i think i get what you are trying to say
the second loop should have same direction of velocity also after $\tau/2$
as the first loop at t=0
so, the reference here is the first loop
 
John Rennie
John Rennie
Yes
 
2017
2017
fair enough :) thanks!
By the way, @Kaumudi.H erm...you know JR bought a new....ummmm......again :-P
 
user228700
@2017 U don't mean a laptop, do you? I know that he bought a couple of tablets...
 
2017
2017
3:44 PM
@Kaumudi.H look up ^^^^^^^^^^
 
user228700
@JohnRennie WHAT THE HECK?!
 
2017
2017
lol :D
 
John Rennie
John Rennie
@2017 You grassed me up! I'll get you for that!! :-)
 
2017
2017
@JohnRennie Well, I didn't mention what you bought.....so no rules broken :D
 
John Doe
John Doe
@EmilioPisanty It didn't get answered, thanks for that.
 
John Rennie
John Rennie
3:45 PM
@Kaumudi.H It's for a friend. I'm going to give it away.
 
user228700
@JohnRennie .__. For the sake of maintaining a relatively sane impression of you in my mind, I will try to believe this claim of yours.
 
John Rennie
John Rennie
... once I've fixed it. It currently has no disk.
 
John Doe
John Doe
@EmilioPisanty So it's basically just a way to describe the polarization of the emitted light in relation to an external magnetic field?
 
user228700
You seem to be on a roll! To whom did u give away the tablets?
 
John Rennie
John Rennie
@Kaumudi.H I haven't given them away. One is for me (to replace one I had already given away) and the other is a spare. I, my niece, my sister in law and my Mum all have this type of tablet so keeping a spare is a potential life saver.
 
user228700
3:49 PM
Ah, OK :-)
 
John Rennie
John Rennie
Did you send your poem?
 
user228700
@JohnRennie Yes, I did :-) On the podcast, they give dubious advice to listeners who send in questions so I sent in a question as well.
 
John Rennie
John Rennie
Are they going to advise you on how to get over your Coldplay obsession?
 
user228700
-____-
 
John Rennie
John Rennie
:-)
 
user228700
3:52 PM
No, I sent in a question that is loosely related to the subject of my e-mail: On conversations and the art of keeping them going.
 
John Rennie
John Rennie
Mentioning food seems to work here ...
 
user228700
I might have to wait for a few weeks to find out whether or not my question/poem made it.
 
user228700
@JohnRennie Hmm?
 
John Rennie
John Rennie
@Kaumudi.H Mentioning food seems to work for keeping the conversation going.
 
user228700
Ah, yes :-) My question was related to social settings in "real" life.
 
John Rennie
John Rennie
3:55 PM
You don't want to bother with real life. The Internet is so much more fun.
 
user228700
:-) I'm going to university later this year; I might need to bother with it some.
 
John Rennie
John Rennie
Ah, OK :-)
 
user228700
I've written it nicely! And the subject seems at least a little intriguing, no?
 
John Rennie
John Rennie
I recall that when I was younger I used to struggle with conversations, but these days I'm a chatterbox and you can't shut me up. The onset of senility probably.
 
user228700
> The onset of senility
 
user228700
3:59 PM
Certainly! x'D
 
John Rennie
John Rennie
A laptop obsession is the first sign.
 
user228700
Exactly!
 
user228700
> These days I'm a chatterbox
 
user228700
Ah, so u are more of an extrovert, are you?
 
John Rennie
John Rennie
Not really. I just stopped caring what people think of what I say.
 
user228700
4:00 PM
I doubt if that's the same thing...
 
John Rennie
John Rennie
Well I think i used to struggle with conversation because I was worried I'd say something silly and everyone would smile patronisingly at me.
 
user228700
Ah, I see.
 
John Rennie
John Rennie
But now everyone does that anyway, so what the hell :-)
 
user228700
I don't quite struggle but my "issue" is a bit different. I'll forward the mail to you if u'd like to see it :-)
 
John Rennie
John Rennie
If you'd like to share it, though my judgement in areas other than physics (and laptops) is not to be relied on.
 
user228700
4:03 PM
U've got mail! :-)
 
user228700
The punctuation-you might notice with a cringe-is terrible.
 
John Rennie
John Rennie
I gave up correcting people's writing a long time ago - it kept getting me beaten up :-)
 
user228700
Thank you :-) It's true; some of them seem completely lost when asked about themselves. It's only understandable, I suppose.
 
user228700
BTW, why is ur font blue in color? O_o
 
John Rennie
John Rennie
@Kaumudi.H Is it?
 
user228700
4:15 PM
It is! :-o
 
2017
2017
@Kaumudi.H It isn't over here!
Only mods have the blue color
 
user228700
Well, no, I meant in e-mail.
 
2017
2017
@Kaumudi.H ow! those are settings....
gmail has color options...
iirc
 
John Rennie
John Rennie
@Kaumudi.H ah. I'm using Outlook and that puts replies in a blue colour by default. I've just never bothered to change the default.
 
user228700
Ah, by default. It looks a bit funny :-)
 
John Rennie
John Rennie
4:17 PM
You're using Gmail?
 
user228700
Yes. What dyou mean "I'm using Outlook"? Isn't ur id at gmail?
 
John Rennie
John Rennie
 
2017
2017
Microsoft Outlook can integrate all the mails from different services ...
 
John Rennie
John Rennie
Those are the defaults.
You can use Gmail with any POP3/SMTP e-mail client.
 
user228700
@2017 I wasn't aware of this!
 
user228700
4:19 PM
This is what it looks like on Gmail:
 
user228700
 
John Rennie
John Rennie
I use two different Gmail accounts, one personal and one for developing on GitHub, and I also have a work e-mail address. Using Outlook is a convenient way to gather all the mail into one place.
@Kaumudi.H shrug - that looks fine to me. I'm not fussed about the colour.
 
user228700
Ohh, I see. And this one is ur work address, I suppose?
 
John Rennie
John Rennie
Perhaps I should send all my mail in Comic Sans :-)
 
user228700
x'D That would give the recipients even more reason to believe the onset of crippling senility.
 
John Rennie
John Rennie
4:22 PM
@Kaumudi.H No, the address you have is my personal address. The work address is on the company's domain pro-networks.co.uk.
 
user228700
Ohh, yes, I found that one on ur website.
 
user228700
Does my e-mail read OK?
 
John Rennie
John Rennie
Yes, it looks fine. I've replied.
 
user228700
Yes, I did read the reply. This was in response to your reply:
 
user228700
13 mins ago, by Kaumudi. H
Thank you :-) It's true; some of them seem completely lost when asked about themselves. It's only understandable, I suppose.
 
John Rennie
John Rennie
4:27 PM
The young are rubbish really. You only realise that when you get old.
 
user228700
Rubbish? :'-( I too-you will notice-am young!
 
John Rennie
John Rennie
I'm too tactful to point that out to you :-)
 
user228700
What did u mean by "rubbish"?
 
ACuriousMind
ACuriousMind
@JohnRennie Plenty of rubbish young people grow up to be rubbish old people :P
 
John Rennie
John Rennie
@ACuriousMind all humans are rubbish except for you and I, and I'm not so sure about you :-)
(traditional Yorkshire saying - paraphrased)
 
ACuriousMind
ACuriousMind
4:35 PM
And you dare call me a cynic ;)
 
user228700
@JohnR: No, really, what did u mean by "rubbish"?
 
2017
2017
@Kaumudi.H garbage :-P
 
user228700
-____-
 
John Rennie
John Rennie
@Kaumudi.H you're reading too much into this. Remember when i said:
> my judgement in areas other than physics (and laptops) is not to be relied on.
 
user228700
Wokay :-P
 
2017
2017
4:37 PM
@Kaumudi.H The only catch is that all garbage turns worse with age :D
 
John Rennie
John Rennie
Garbage gets smellier with age, but then so do humans.
Of course wine and cheese get tastier with age ... :-)
 
AccidentalFourierTransform
AccidentalFourierTransform
and so do humans ( ͡° ͜ʖ ͡°)
 
John Rennie
John Rennie
@AccidentalFourierTransform they get tougher though, so you need to cook them for a long time.
 
AccidentalFourierTransform
AccidentalFourierTransform
sure, we all know babies are naturally more tender
 
John Rennie
John Rennie
Indeed. They can be eaten raw with just a dash of barbecue sauce.
:: John looks nervously around for incoming flags ::
 
AccidentalFourierTransform
AccidentalFourierTransform
4:49 PM
ಠ‿↼
 
2017
2017
I used to look like a monkey after birth. Now its better...... :-P I must be wine :'D
@JohnRennie You seem to have a lot of experience :D
I hope you don't have any cannibalism cases against you
 
John Rennie
John Rennie
I ate the evidence
 
AccidentalFourierTransform
AccidentalFourierTransform
I dont like this meme anymore
its not funny if you collaborate
 
John Rennie
John Rennie
Would you like to come to my house for dinner?
 
AccidentalFourierTransform
AccidentalFourierTransform
brb, gotta buy a plane ticket
ok done, see you at 10pm
PS I dont like cheese
 
0celo7
0celo7
4:57 PM
JR does get implicated in cannibalism a lot
I thought he was more into sheep
But maybe I'm wrong
 
Secret
Secret
I derived some formula in maths chat:
$$\int a(n)e^{nu} dn=\sum_{k=0}^{\infty}\frac{(-1)^{k-1}a^{(k)}(n)e^{nu}}{u^{k+1}}$$

Now attempting to apply method of snake oil to knock out that sum
 
John Rennie
John Rennie
@0celo7 food first, romance later
 
AccidentalFourierTransform
AccidentalFourierTransform
sheep first, sheep later
 
0celo7
0celo7
@JohnRennie are you Hannibal Lecter
@AccidentalFourierTransform hey, this isn't Iraq
Oh wait, that's goats
 
John Rennie
John Rennie
Incidentally, i read this a couple of weeks ago and I strongly recommend it:
Feb 16 at 10:33, by John Rennie
www.amazon.co.uk Cannibalism: A Perfectly Natural History
Bill Schutt
Algonquin Books

Eating one s own kind is completely natural behavior in thousands of species, including humans. Thro....
 
0celo7
0celo7
5:01 PM
Ignore me
 
John Rennie
John Rennie
Despite the title it's mostly about cannibalism in animals e.g. spiders and preying mantises. The extent to which humans have ever practiced cannibalism is a matter of some debate.
 
0celo7
0celo7
So it doesn't defend human cannibalism?
So how do you have time for a book on cannibalism but not for balls?
 
John Rennie
John Rennie
It does mention human cannibalism, but there's very little direct evidence that it has ever been standard practice for any societies.
You get cases like the well known plane crash in the Andes, but they are pretty exceptional.
And some societies eat their dead as a way of honouring them.
But cannibalism as in the comic book idea of capturing people and putting them in pots seems to be rare to the point of non-existence.
 
vzn
vzn
@JohnRennie a ghoulish, macabre topic. but cannibalism is not to be confused with human murder/ sacrifice both of which are not so rare in human cultures over the millenia. re your topic, you might find this relevant dailymail.co.uk/news/article-2885704/…
 
John Rennie
John Rennie
The Daily Mail? You're citing the Daily Mail and you expect me to take you seriously? They can't even talk sense about Brexit so the chance of them having anything useful to say about sociology is negligibly small.
There's only one good use for the Daily Mail and the paper is a bit hard for that.
4
 
2017
2017
5:11 PM
@JohnRennie I will give you a surprise visit when I go to Europe next time. We can go human hunting together. (I have your address :-D)
@JohnRennie I read the first few pages from an online pdf...will complete the book after my exams are over!
It looked interesting :)
 
John Rennie
John Rennie
Are you doing the same exams as Kaumudi?
 
2017
2017
@JohnRennie Yep
 
John Rennie
John Rennie
Good luck!
 
2017
2017
Thank you ^_^
 
John Rennie
John Rennie
Anyway I'm off to get a beer and finish American Gods.
Sanity can now return to the physics chat.
 
vzn
vzn
5:31 PM
 
0celo7
0celo7
@JohnRennie Huh?
Rolling up a newspaper and beating people with it works best with hard paper.
 
Sir Cumference
Sir Cumference
@MartianCactus Want a quick intro to cosmology?
 
0celo7
0celo7
@SirCumference So what is the topology of spatial slices of the universe?
 
Sir Cumference
Sir Cumference
@0celo7 Dude stahp
 
MartianCactus
MartianCactus
not right now :P
 
0celo7
0celo7
5:39 PM
?
 
MartianCactus
MartianCactus
im kinda busy
 
Sir Cumference
Sir Cumference
Ask @ACM or @JohnRennie Rennie this stuff
 
MartianCactus
MartianCactus
maybe tomorrow
its night here
 
AccidentalFourierTransform
AccidentalFourierTransform
JohnRennie Rennie
 
0celo7
0celo7
@SirCumference why would ACM know?
 
Jaime Gallego
Jaime Gallego
5:40 PM
J R R
Tolkien
 
Sir Cumference
Sir Cumference
@0celo7 I dunno, he likes cosmology
 
0celo7
0celo7
@ACuriousMind does not like cosmology, I guarantee
 
Sir Cumference
Sir Cumference
He's helped me on a few things
Like how the event horizon changes in the Big Rip
 
ACuriousMind
ACuriousMind
@0celo7 That's correct
@SirCumference That's not correct
 
Sir Cumference
Sir Cumference
D:
 
ACuriousMind
ACuriousMind
5:42 PM
That I know some basics about it doesn't know I like it
 
Sir Cumference
Sir Cumference
@ACuriousMind Event horizon changing in a nonstandard cosmology is a basic?
 
ACuriousMind
ACuriousMind
@SirCumference I don't remember any "event horizon changing"
 
Sir Cumference
Sir Cumference
@ACuriousMind I thought it was you who said the event horizon shrinks
Oh wait, that might've been JR
 
ACuriousMind
ACuriousMind
Ah, you're talking about the particle/Hubble horizon
 
Sir Cumference
Sir Cumference
@ACuriousMind Er, no, I'm talking about the cosmic event horizon
 
ACuriousMind
ACuriousMind
5:43 PM
@SirCumference It wasn't difficult to figure out from the Wikipedia page and what I knew, so yes :P
 
Sir Cumference
Sir Cumference
Hubble horizon changes, that's a given. But I was surprised by the event horizon shrinking.
 
0celo7
0celo7
@ACuriousMind This is probably a stupid question, but from stat mech we know that there are three spatial dimensions. How does holography deal with this?
I'm not on weed, just wondering about things
 
ACuriousMind
ACuriousMind
@0celo7 Holography just says that an $n$-dimensional theory of quantum gravity is equivalent to a $n-1$-dimensional quantum field theory on the boundary. It doesn't say the $n$-th dimension doesn't exist
 
Sir Cumference
Sir Cumference
@DavidZ @ACuriousMind So...is the site's logo gonna be upgraded to a vector graphic soon?
 
ACuriousMind
ACuriousMind
@SirCumference ...what?
 
0celo7
0celo7
5:48 PM
why are you obsessed with vector graphics
 
Sir Cumference
Sir Cumference
It's kind of strange how we use a raster while other sites use vectors
 
0celo7
0celo7
how about I teach you about vector spaces instead
 
Sir Cumference
Sir Cumference
@0celo7 Raster logos are ugly
 
ACuriousMind
ACuriousMind
Why should we know anything about that? The moderators have nothing to do with site design or functionality
 
Sir Cumference
Sir Cumference
:36108295 D:
@ACuriousMind Wait, who deals with site design?
 
ACuriousMind
ACuriousMind
5:49 PM
@SirCumference SE employees
 
Sir Cumference
Sir Cumference
@ACuriousMind Huh, really?
 
ACuriousMind
ACuriousMind
Sure
 
Sir Cumference
Sir Cumference
I guess I'll make a meta post or email them
 
ACuriousMind
ACuriousMind
Make a meta post if you feel that strongly about it
If it is about design features not specific to physics.SE, Meta Stack Exchange is the right place, though
 
0celo7
0celo7
@ACuriousMind but how does that n-1 dimensional QFT describe the cubic expansion of gas?
 
ACuriousMind
ACuriousMind
5:52 PM
@0celo7 Since the theories are equivalent, all the expectation values and so on of everything are the same. It gives the exact same predictions. I can't answer that in any more detail since the holographic principle is merely conjectural, and I have no idea if any of the known AdS/CFT correspondences describes any situation remotely comparable to the expansion of gases.
 
0celo7
0celo7
well those theorists need to answer basic questions first!
@ACuriousMind Mr. Linguist, why does Yosida use a mathfrak E for the Frechet space of smooth functions?
 
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