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Physics Meta
Physics Meta
12:22 AM
0
Q: Compinsation for Full Time Moderators

JenDo moderators here get any kind of compensation for all their efforts and help?

discussion support scope
 
 
1 hour later…
knzhou
knzhou
1:27 AM
Does anybody here ignore tags, and if so, which ones are good to ignore?
Basically, I want to cut out everything about SR kinematics without removing anything else.
 
0celo7
0celo7
1:57 AM
@knzhou lol
 
HDE 226868
HDE 226868
2:47 AM
Is anyone familiar with the "modulus of precision" of a Gaussian distribution?
 
0celo7
0celo7
3:00 AM
@HDE226868 is statistics even real
 
HDE 226868
HDE 226868
@0celo7 When applied to a velocity distribution, yes.
 
dmckee
dmckee
3:15 AM
@knzhou I suspect you are out of luck on that one. The beginners who ask those things are often bad at tagging (because good tagging takes a degree of understanding).
 
0celo7
0celo7
3:55 AM
@HDE226868 what about presidential primary votes
 
Sidarth
Sidarth
4:07 AM
hi
 
 
2 hours later…
David Z
David Z
6:02 AM
@ACuriousMind hm. Well, I never really liked that policy of deleting answers just for being non-mainstream, but I suppose the FAQ should take precedence. Let me edit my answer accordingly.
@ACuriousMind the rationale behind the FAQ you linked was that there is a distinct difference between a non-mainstream answer and an answer that is merely wrong. But you'd probably have to ask @Manishearth to explain it; I don't feel like I properly understand that difference.
I do tend to hold back from handling such flags, unless it's a really obvious case.
 
 
5 hours later…
hubot
hubot
11:05 AM
Hi!
 
yuggib
yuggib
11:44 AM
hullo
 
hubot
hubot
What are you think about book Physics Jay Orear?
I'm learning from Physics Jay Orear.
 
yuggib
yuggib
don't know the book
sorry
 
hubot
hubot
And what are you think about Feynman lectures?
 
yuggib
yuggib
don't know it either, but I think they should be a good starting point. Personally, I would go directly with Landau-Lifshitz
 
hubot
hubot
12:00 PM
Are these exercises in this course easy or difficult?
I think about Landau-Lifshitz
 
yuggib
yuggib
@hubot they're the Russian school, so the exercises are....not the easiest ones :-P
 
hubot
hubot
And is there a Polish version of this course?
Or although English version?
 
yuggib
yuggib
@hubot the english version is freely available on the web
 
hubot
hubot
Do you think that this course will be good to start with?
 
yuggib
yuggib
I think it provides extremely good insights
however it is very theoretical in nature
 
hubot
hubot
12:05 PM
I've website only that not yet translated.
My website is in Polish.
 
yuggib
yuggib
which website?
 
hubot
hubot
You can use Google Translate
 
yuggib
yuggib
sorry, but I do not see the point of looking at your polish website :-P
anyways it is good to see young people interested in physics
 
hubot
hubot
I'm going to translate website as I find time
 
yuggib
yuggib
@ACuriousMind @Danu @0celo7 etc...new hobby/challenge: adding pedantic comments on MO posts by fields medalists
with the rule that they have to be:
1. mathematically correct;
2. at least partially improving, or making more precise, the post;
3. (facultative) annoying
it fulfils 1 and 2, but maybe not 3
 
hubot
hubot
12:23 PM
I'm into IT, physics, maths. In freetime I like DIY, electronics etc.
 
 
2 hours later…
ACuriousMind
ACuriousMind
1:57 PM
@yuggib I thought "pedantic commentary" was the standard mode of operation on MO already :P
 
yuggib
yuggib
@ACuriousMind :-D probably that's true
 
Physics Meta
Physics Meta
0
Q: Why was my question about a *collection* of textbooks to use to *prepare* for QFT closed?

SSDIt was called "Need A Collection Textbooks To Use As Stepping Stones to QFT" In my mind, asking about a "no-nonsense intro to QFT" and asking for a set of textbooks together which would prepare one to even read a QFT intro, from the position of only having completed Griffith's Introduction to QM,...

discussion questions closed-questions close-reasons
 
ACuriousMind
ACuriousMind
And there go my close votes for the day already. The close queue has become more busy again lately, hasn't it? Is it people returning from Christmas holidays?
 
yuggib
yuggib
just vtc myself
in my rep level, the queue is now clean
@ACuriousMind however with Fields medalists the commentaries are usually a lot more respectful than usual
 
Hitesh Pathak
Hitesh Pathak
2:57 PM
Hey can anyone here help me with the concept of inertial frame please!!
I am sick of questioning and waiting for answers..
We intuitively know what force is but when we encounter gravitation should not we suspect that it can be a pseudo force afterall its invisible and that earth is not an inertial frame
Please reply my exams are near and I dont know why I m doing this in details which is not cared of in my class
 
Emilio Pisanty
Emilio Pisanty
Hi all!
Free books!
> Springer seem to have had a massive attack of conscience regarding the price of science textbooks, and as such you can currently download books published before 2005 for free and legally from their website:
 
yuggib
yuggib
3:41 PM
@ACuriousMind maybe it was already posted...but T____T:
they have no shame...
the proof of the Poincaré conjecture got less advertising than this...
piece of...
 
0celo7
0celo7
@yuggib link kaput
@ACuriousMind Do you know of a general procedure for finding the save data for a given game on the hard drive?
@ACuriousMind Or even better: Does the "delete local content" button on Steam remove saves?
@yuggib Ignore that, I can't read
 
Emilio Pisanty
Emilio Pisanty
4:10 PM
@0celo7 Yeah, these troyhunt.com/2016/01/… come to mind
@0celo7 Have you got the URL for this one?
I've been looking for it for some time.
 
knzhou
knzhou
I'm answering a lot of semi-bad questions with one-sentence comments.
I used to write one-sentence answers instead, but somebody told me that was bad because it encouraged semi-bad questions.
Are comments also bad?
 
0celo7
0celo7
@EmilioPisanty No, it's deleted.
Maybe you can find the chat post where I announced it.
@EmilioPisanty Search my chat posts for "http://physics.stackexchange.com/questions/" ...that might work.
@EmilioPisanty Hmm, maybe I did not post it in chat. Sorry.
 
ACuriousMind
ACuriousMind
4:38 PM
@yuggib What the...
 
Emilio Pisanty
Emilio Pisanty
@0celo7 Yeah, I know. Do you remember the original question that sparked it?
 
0celo7
0celo7
 
Emilio Pisanty
Emilio Pisanty
@0celo7 Cool, yeah, that's useful
 
yuggib
yuggib
@ACuriousMind what the...indeed
either we understand nothing, or we understand too much
 
Danu
Danu
4:54 PM
@EmilioPisanty Wow!!!
@EmilioPisanty Where are you quoting this from?
 
Emilio Pisanty
Emilio Pisanty
@Danu Internal email
Can't vouch for its accuracy
But I can vouch for me having just downloaded a bunch of books
(... of which I can't tell whether they were free or not a few weeks ago)
 
Danu
Danu
It's a bit dodgy; I think books that are reprinted/had new editions after 2005 are not free (though they were published earlier)
Still pretty neat
Also see this @EmilioPisanty
There must be something more complicated behind this.
Is it only for Chemistry?
 
Emilio Pisanty
Emilio Pisanty
@Danu Naw, click on the x on the sidebar and you can see any subject you want
@Danu Yeah, they're not all free
 
Danu
Danu
The physics one just gives 18 free books :(
Still pretty neat.
 
Mike Miller
Mike Miller
5:11 PM
A while back they were all available for free by mistake. There was a big hubbub while people downloaded every single GTM that was at leas ten years old. But, uh, not every author agreed "yeah I'm good with my book being free".
 
Danu
Danu
Wuuuut
Man... that's a shame :(
 
Emilio Pisanty
Emilio Pisanty
@Danu You need to make sure you're looking at the broadest category
has 409 links
 
Physics Meta
Physics Meta
0
Q: EM Wave shielding of different frequencies

tjsb55Is more aluminium required in Faraday cages to block AM or MW radio waves compared to FM frequencies (of equal power)? If yes, is this difference directly proportional to the decrease in frequency (FM to AM/MW)?

support
 
Emilio Pisanty
Emilio Pisanty
some of them not free, but many are
 
Danu
Danu
I think it's at least a little bit of a moral obligation (but I know I'm not standard in this respect)
@EmilioPisanty I get 18 links.
Is this location-dependent?!
@yuggib WTF. Is it me or can we take any formula featuring $\pi$ as a "new formula for determining $\pi$"?
 
yuggib
yuggib
5:17 PM
@Danu more or less...
 
Danu
Danu
So the main "result" is:
We found a formula that is equivalent to an already known formula featuring $\pi$?
 
yuggib
yuggib
that's the reason for the T__T
 
Danu
Danu
Woop-dee-fucking-doo
 
yuggib
yuggib
and a lesson that you can write very bad papers
and still got them accepted in respectable journals
 
Danu
Danu
Also this quote:
> "I find it fascinating that a purely mathematical formula from the 17th century characterises a physical system that was discovered 300 years later,"
LMAO
 
Emilio Pisanty
Emilio Pisanty
5:20 PM
@Danu Huh. Yeah, maybe some location dependence.
Let me Hola to Germany and see what it gives
Nope, still gives me 409 results
 
Danu
Danu
Straaaange...
It's probably the Springer site, then.
Which search criteria do you have?
When I click your link, the criteria I get are English, Physics, Books, 1855-2005
 
Emilio Pisanty
Emilio Pisanty
@Danu Yeah, exactly
 
Danu
Danu
@EmilioPisanty Weird... What do you see if you click my link?
 
Emilio Pisanty
Emilio Pisanty
How many results do you get here ?
 
Danu
Danu
354
 
Emilio Pisanty
Emilio Pisanty
5:25 PM
@Danu Post it again?
@Danu Bizarre. I get 5746
 
Danu
Danu
17 mins ago, by Danu
http://link.springer.com/search?facet-content-type=%22Book%22&date-facet-mode=be‌​tween&facet-discipline=%22Physics%22&just-selected-from-overlay=facet-discipline&‌​facet-start-year=1855&facet-end-year=2005&facet-language=%22En%22&just-selected-f‌​rom-overlay-value=%22Physics%22&showAll=false&query=
@EmilioPisanty D00000d :(
 
Emilio Pisanty
Emilio Pisanty
@Danu 409
 
Danu
Danu
dafuq
 
Stan Shunpike
Stan Shunpike
@ACuriousMind I roughly get why the QED lagrangian has a U(1) symmetry. Why is this important to know and what does it tell me about the nature of electromagnetism that isnt evident from classical ED?
 
Danu
Danu
If you talked about the U(1) symmetry in your classical ED lecture/studies then you won't learn much new from the quantum version.
 
Stan Shunpike
Stan Shunpike
5:33 PM
@Danu ok thats what i wanted to know
 
0celo7
0celo7
@EmilioPisanty 18
Murricans get shafted
 
Emilio Pisanty
Emilio Pisanty
@0celo7 Huh
 
ACuriousMind
ACuriousMind
@Danu 354 here, too
So it seems to be dependent on location.
 
hubot
hubot
I know - 1969th
How to learn easily do the Feynman exercises or exercises from L.D. Landau's book?
 
ACuriousMind
ACuriousMind
5:53 PM
@Danu: Parallel thinking on that question, you answered what I commented :P
How that question hot three upvotes in a few minutes is beyond me.
 
Danu
Danu
@ACuriousMind lol you get preference in the editing
I got "ACM is already editing the tags"
Great minds...
 
ACuriousMind
ACuriousMind
@Danu Interesting, I didn't know we had such an edit block
 
Danu
Danu
Lame, it also discarded my title/body edits :\
Welp, redid them now.
I'm a little tempted to expand my answer to actually include the derivation as part of my "basic GR" answer series ;)
I've got the "EFE like you're 5 years old" and the "Newtonian limit 101" down already :P
(and those are hiiiighly upvoted!)
 
ACuriousMind
ACuriousMind
@Danu But...this is less basic GR and more "extremize this functional for me" :P
 
Danu
Danu
@ACuriousMind Yes, yes, I know
Hence I didn't really write the answer out. Maybe I should delete my answer.
Yeah, it's not really worth an answer.
...maybe I'll change my mind again later.
Holy sh!t, the number of deleted answers here!
 
ACuriousMind
ACuriousMind
6:03 PM
@Danu No surprise, it's the highest voted unanswered question.
I love this part:
> Regularization by dimensional reduction (DRed) was introduced by Siegel in 1979 and was shortly after seen to be inconsistent (Siegel 1980). Despite this, it is commonly used in supersymmetric calculations since it has most of the advantages of (normal) dimensional regularization (DReg) and (naively) preserves supersymmetry.
Ah, it's inconsistent, but we'll keep using it, anyway
3
 
Danu
Danu
I'm surprised at the fact that there are 9(!) of them.
@ACuriousMind Classic physicists
It got the right result... RIGHT?!
It didn't? Eh... Close enough
 
Mike Miller
Mike Miller
:I
 
Danu
Danu
I must've said this before, but in the first lecture on string theory the professor said:
"But... at least we get a prediction for the number of spacetime dimensions... (!!!) And it is wrong!"
"We must overcome the observations"
:D
 
0celo7
0celo7
6:31 PM
Are there people using Steam who pick the first few options?
Or...anything worse than DSL/Cable
 
Danu
Danu
You can say "Don't Know"...
 
0celo7
0celo7
-{don't know}
Although, are there people who use Steam who don't know?
 
Mike Miller
Mike Miller
My aunt plays bejeweled on steam, so yes
 
0celo7
0celo7
Why would you not know?
 
0537
0537
It tells you though, when you dl a game.
 
0celo7
0celo7
6:33 PM
>RAM: 16384 Mb
Uh, Steam
Is that bit or byte
 
0537
0537
I feel like I've seen this before.
 
user54412
Judging by how 30% of all online gamers think all servers have lag, I'd say (1) many people have terrible internet and (2) they're all in denial about it.
 
0celo7
0celo7
I have good internet and all servers have lag
What are you implying
 
Danu
Danu
lel
Non-EU level interwebs
(though Germany isn't great either, compared to my hometown)
 
0celo7
0celo7
My internet in a small German village when I lived there was terrible
 
Danu
Danu
6:45 PM
Small village is always bad.
 
0celo7
0celo7
At least it wasn't Katzenbach
 
hubot
hubot
Are school textbooks is good to learn physics because I want to dispel doubts, which my teacher causes saying: "Feynman exercises is too hard. You should learn junior school programme"?
 
0celo7
0celo7
"dispel doubts" Interesting wording...
 
hubot
hubot
I very interested in physics and I think that Feynman exercises, Landau course and Jay Orear books is good begin.
With Jay Orear exercises I've no problem.
 
user54412
Feynman taught college, and Landau doesn't teach (he just makes up hard problems and abstruse wording to look smart in front of others; must've had an inferiority complex)
 
Danu
Danu
6:50 PM
@ChrisWhite That's a very cynical assessment, and I think it's unwarranted.
The books even have solutions (to at least some of the exercises)
 
hubot
hubot
What are you think about school programme? Is school good learning basics on physics?
 
user54412
@Danu I know no one agrees with me. But I have little patience for anyone who makes basic physics difficult and broadly inaccessible. Comes off as too much intellectual elitism for me.
 
Anthony
Anthony
Does anyone here know much about quantum computing?
 
0celo7
0celo7
@Anthony : @DanielSank pretends to know a little about it.
 
Danu
Danu
@ChrisWhite "basic physics"
 
Anthony
Anthony
6:54 PM
Well, I'll leave a question- maybe someone will see it. I'm wondering the best way to prepare an $N$-bit cat state, where best means smallest number of gates, where I'm using the canonical gate set. I'm also wondering if there are any ways to prove minimality.
 
Danu
Danu
implying L&L does not go further than introductory textbooks?
@Anthony Are you the Anthony I know?
 
Anthony
Anthony
@Danu Which is that?
 
hubot
hubot
I'm into physics for a year.
 
Danu
Danu
@Anthony You'd probably know if you were the right one :P
The one at TMP.
 
Anthony
Anthony
Unfortunately not then, I suppose. That would have been exciting. What is TMP?
 
Danu
Danu
6:58 PM
 
hubot
hubot
I've problem from Feynman exercises. It is known that heat is related only to the movement of particles within the body. What is the difference between a hot, motionless ball for the game of baseball and the ball moving quickly?
 
Anthony
Anthony
@Danu Fancy stuff.
I'm just a lame undergrad at Berkeley.
 
Danu
Danu
You think?
 
Anthony
Anthony
It looks fancy, at least.
 
Danu
Danu
Don't let the "elite" fool you---it's pretty normal here.
 
Anthony
Anthony
6:59 PM
:o
 
0celo7
0celo7
@Anthony NB: His normal is not most people's normal
 
Danu
Danu
meh
 
Anthony
Anthony
lol
 
user54412
@Anthony Berkeley? Undergrads there are many things, but "lame" isn't one of them ;)
 
Danu
Danu
@Anthony That's probably a lot better, prestige-wise, than me.
 
0celo7
0celo7
7:09 PM
@Danu But you're Elite®
 
Danu
Danu
But he's at a more prestigious university.
Top US schools are simply more widely known than top EU universities.
 
user54412
^ Typical American, thinking the world revolves around them
 
Danu
Danu
@ChrisWhite Sadly the Europeans also know the US schools better ;)
It might just be a PR/media thing.
 
user54412
-1
Q: What are some nice universities for mathematical physics in Europe?

user3183950I am a French student in engineering in applied Physics, but I want to study mathematical physics. I am looking for good universities in this topic in Europe. I have found EPFL (in Swiss), Oxford and Cambridge. I think I have good grade to go in EPFL but probably not good enough to go in Oxford...

mathematical-physics soft-question education
 
user54412
apparently so
 
Danu
Danu
7:19 PM
@ChrisWhite That's a funny coincidence!
But yeah... People in Amsterdam don't know about LMU.
 
hubot
hubot
What it is actually book Feynman tips?
What is book Feynman tips on Physics?
 
Danu
Danu
A way to make more money?
 
hubot
hubot
I've actually Feynman lectures and Feynman exercises books.
How do I know that I understand Feynman lecture for example "The atoms in motion"?
 
DanielSank
DanielSank
7:44 PM
@Anthony What's a canonical gate set? Every system has different entangling gates.
 
TanMath
TanMath
where is @MarkMitchison! I wish he was here right this moment
 
Danu
Danu
@TanMath What makes you so needy? :P
 
Anthony
Anthony
8:08 PM
@DanielSank Actually I don't know what I was saying.
I had only just begun to think about it with one qubit.
So I was thinking $X,Y,Z,H$.
Hmm...
 
0celo7
0celo7
 
TanMath
TanMath
8:20 PM
@Danu i need help with an open quantum system project and/or some python programming for the project...@MarkMitchison knows what the project is about
I bet @DanielSank might be able to help but he just left looks like
I wish somebody here knows open quantum systems and python...
 
0celo7
0celo7
Quantum snek
hehe
 
John Duffield
John Duffield
@DavidZ : the problem here is that people like ACuriousMind will cry "that's not mainstream" or "that's not peer reviewed" when we're talking about special relativity and the wave nature of matter, because he can't offer a counter-argument.
 
Danu
Danu
@JohnDuffield No, when we're talking about your take on these things.
Predicted response: "I didn't make these things up" with irrelevant link.
 
0celo7
0celo7
@Danu wow calling Einstein irrelevant
you think you're smarter than Einstein, kid?
 
Behzat
Behzat
lol
 
John Duffield
John Duffield
8:34 PM
@Danu : special relativity was never peer reviewed, it didn't get accepted until the late 1920s, and de Broglie got his Nobel in 1929. And what I get when I refer to material on the arXiv is that it's my personal theory. But in truth it's I don't know about it so it can't be mainstream. Coming from somebody aged 22. Or 18.
 
0celo7
0celo7
@JohnDuffield You say X implies Y and then point to someone saying X in a completely different context as proof of Y.
 
Danu
Danu
@JohnDuffield Ha-ha-ha. Einstein's annus mirabilis paper on SRT was published in Annalen der Physik.
 
John Duffield
John Duffield
@0celo7 : I give you the references. You don't read them.
 
0celo7
0celo7
@JohnDuffield You've given me blogs and uncited papers. Nowhere have you shown me that anyone agrees with you.
 
John Duffield
John Duffield
@Danu : go and read up about Einstein and peer review.
 
0celo7
0celo7
8:37 PM
I even asked a question on the main site and you failed to answer with hard sources.
 
Danu
Danu
@JohnDuffield The first link there contains a lot of nonsense. It claims that at most one paper by Einstein was subjected to peer review. Nice.
 
John Duffield
John Duffield
@0celo7 : I've given you Einstein and the evidence. You dismiss it all.
 
0celo7
0celo7
@JohnDuffield Einstein has never agreed with what you say.
 
Danu
Danu
It's well known that Einstein was not fond of peer review in his later years; he once got made the stupendously large mistake of thinking he had proven that gravitational waves cannot exist. I think it was Robertson himself who reviewed that paper and rejected it. This pissed Einstein off, but in the eventually-published version of the paper the conclusions had been drastically changed ;)
@JohnDuffield What's more funny is a claim from someone who has no formal education in physics that he knows better what "mainstream physics" means than a community of people, many of whom are graduate students+ in terms of physics education.
 
John Duffield
John Duffield
@Danu : Einstein didn't have to worry about peer review in his miracle year. He just sent the papers to Max Planck. Have a read of this. Doubtless ACM will now jump up and say that article's not peer reviewed.
 
0celo7
0celo7
8:41 PM
@Danu Silly man, it's Einstein's claim.
 
ACuriousMind
ACuriousMind
It's completely irrelevant whether Einstein was peer-reviewed or not. The modern criterion for mainstream physics is publication in a peer-reviewed journal.
3
 
Danu
Danu
@JohnDuffield It may well have been the case that the process was violated in the particular case of the 1905 papers; but I don't think your links provide sufficient evidence to claim this.
Also, the <100% acceptance rate of the journal suggests that at least some review did take place.
 
John Duffield
John Duffield
@Danu : I do in some respects. A graduate student has had three years, mostly filled with mathematical aspects of physics. He just hasn't had time for the wider reading.
 
Danu
Danu
@JohnDuffield You can keep telling yourself that, if it allows you to keep your own world-view intact. That does not mean that it's correct.
 
0celo7
0celo7
@Danu Well, have you read the original Einstein, Maxwell, etc. papers?
 
John Duffield
John Duffield
8:44 PM
@ACuriousMind : it isn't irrelevant when we're discussing material that is mainstream but some kid says it isn't.
 
Danu
Danu
@0celo7 I've read some of the original Einstein papers, in German, mind you.
If you wanna be a purist, do it right.
They're primarily of historical interest, in my opinion.
 
0celo7
0celo7
@Danu Ooooh German
@JohnDuffield I think he's got you there
@JohnDuffield Would you mind telling me what the disputed material is? I've been away from the main site lately.
 
ACuriousMind
ACuriousMind
@JohnDuffield 1. Stop referring to young people as "some kid", it is patronizing. 2. Which material are you referring to?
 
0celo7
0celo7
@ACuriousMind It's not patronizing, it's just downright dismissive.
 
TanMath
TanMath
@ACuriousMind who are we talking about?
 
Danu
Danu
8:48 PM
^lol
Let's just stop the discussion again, guys.
 
TanMath
TanMath
what is going on?
 
ACuriousMind
ACuriousMind
If you seriously have no idea, be glad, and let it stay that way :P
 
Danu
Danu
@TanMath Just ignore it.
 
TanMath
TanMath
@ACuriousMind is it something with John Duffield again?
 
Mike Miller
Mike Miller
lol
 
TanMath
TanMath
8:52 PM
anyway, to make sure, there aren't any open quantum system experts?
 
0celo7
0celo7
@TanMath Yes.
Hence all the @JohnDuffield s
 
TanMath
TanMath
@MikeMiller no, seriously... he is infamous here...
@0celo7 what does he say now??
 
Danu
Danu
@MikeMiller Sigh... Welcome to the drama...
 
John Duffield
John Duffield
@Danu : good for you. So you'll have read this then: "die Ausbreitungs-geschwindigkeit des Lichtes mit dem Orte variiert".
@0celo7 : no, I've got him.
 
Danu
Danu
@JohnDuffield That's not a complete sentence.
 
Mike Miller
Mike Miller
8:54 PM
Maybe you index people can answer this
 
ACuriousMind
ACuriousMind
"index people"
 
TanMath
TanMath
^
 
Danu
Danu
@MikeMiller lel
 
John Duffield
John Duffield
@Danu : I'll find you the complete sentence.
 
Mike Miller
Mike Miller
@ACuriousMind: Well... I mean...
 
ACuriousMind
ACuriousMind
8:56 PM
We are the proud people of the Index. Bow to the Index or prepare to be vanquished!
 
Danu
Danu
@JohnDuffield Don't bother. As I indicated some time ago, I have no interest in discussing anything more with you---I'm already sorry that I breached this policy today.
 
ACuriousMind
ACuriousMind
Also, I think the comment is right. I bet one can write down a flat metric such that the second derivatives don't vanish, but since the Riemann tensor vanishes, such an inverted formula has not much chance of existing.
 
John Duffield
John Duffield
@Danu : I will find you the complete sentence, and you can translate it for the benefit of everybody here.
 
Danu
Danu
@ACuriousMind Good point.
Use the Milne universe
I think it's a Minkowski-in-disguise.
 
ACuriousMind
ACuriousMind
Ah, finding the actual example I'll leave to you GR freaks ;)
 
Mike Miller
Mike Miller
8:59 PM
I coulsnt read it, so couldn't engage :)
 
0celo7
0celo7
Or polar coordinates for the plane?
 
TanMath
TanMath
no open quantum system experts?
 
Danu
Danu
@ACuriousMind I already gave it to you ;)
 
ACuriousMind
ACuriousMind
@0celo7 Oh, you're right, that already suffices
 
0celo7
0celo7
@ACuriousMind Ah, so you don't have me blocked
 
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