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6:00 PM
@obe i didn't check to see if you got an answer you wanted to hear but usually it's quite easy to tell by the way they look at you + level of eye contact. Observe how she looks at normal day-to-day people she talks with. Then, talk to her yourself and you'll notice if she likes you or not probably. Not everyone is the same, obviously. Some people don't show eye contact because they might be shy. Best way to find out is talking to them more often and reading them yourself.
 
Another difference for permanent notes vs the temporary ones is that they are nearly word by word (because I cannot afford them to be misinterpreted). This means in conferences and stuff, I will need to write very fast to keep pace with the speaker (and most importatn things on their slides if the slides are unavaiable afterwards)
and there do exists those instance where I pushed so hard that after the seminar I almost fainted
My roughwork is even messier. For example:
There are at least 6 different types of calculations present on this one single pieces of paper in random corners forming clusters
Not to mention, they are used to quickly jot down dreams (explains the two detailed humanoid drawings)
One single piece of roughwork can have 1-10 calculations on it at the same time at various orientations and overlapping if different colored pens were used
 
user218912
@Obliv okay I'll keep that in mind, what about through texting?
 
user218912
since I barely see her irl anymore.
 
What do you text about?
 
user218912
school and stuff I guess...
 
6:11 PM
There are very little tells in texting. Whether they're talking to you often because you're their friend or because they like you is hard to know, honestly.
It's easy to know when they don't like you at all, though. That's when they don't respond ;D
like, ever. Not because they're busy or anything.
 
user218912
define not responding?
 
hello
 
user218912
does not ever starting a conversation count as not responding? D:
 
ex: you ask them about their day. They respond a day later. Then you respond immediately, then they respond 2 days later. etc. for most people, this means they aren't interested in talking to you. You are either a friend to them or just an acquaintance at this point.
 
user116211
@Secret That's readable.
 
6:14 PM
Hi, everybody.
 
user116211
@DanielSank o/
 
Or, in the rare case( i don't think this is your case), they pretend to not be interested so that they don't sound desperate. This is really hard to tell and pretty immature so I'm not sure if it's likely.
 
@DanielSank, hello! I just wanted to say thanks again for everything, that was so awesome being able to visit the lab!
 
user218912
@Obliv well rip :(
 
@MAFIA36790 Besides for the permanent notes reason, another reason is because it is literally transcribing everything from the professor's blackboard
 
6:16 PM
@obe Man, even I think you're overthinking this, and I'm the master of overthinking. Just ask her out (coffee/a movie/whatever you feel comfortable with), a "no" is not the end of the world. Don't try to divine her thoughts through subtle "tells" or by "reading" her as obliv calls it, you'll only make yourself go crazy with that.
 
@obe If you weren't close to her to being with, it's hard for her to start conversations with you even if she did like you. You'd have to keep texting her and make it clear to her that you like talking to her so that she'll feel comfortable to start conversations with you.
 
You're the master of overthinking?
 
That, or so that she shows that she isn't interested by continuing ignoring you for a couple weeks :D
@acuriousmind she's at a diff. school I think so asking her out is nearly impossible unless he visited her.
 
If actually meeting up is out of the question, then wtf is all the fuzz about?
 
holding onto escaping dreams
 
user116211
6:18 PM
15 hours ago, by obe
@SirCumference i'd seriously die
 
user218912
@Obliv pretty much
 
user116211
He is that desperate :(
 
@Obliv Because that sounds like a good plan. Right.
 
user218912
yes.
 
@acuriousmind you're the mature one here. I almost did something similar to @obe in my senior year of highschool. I had to move on though so it didn't escalate that high. I ended up getting her number but I couldn't ask her out the last couple weeks of school ;(
 
6:20 PM
@MAFIA36790 \o
@heather It was my pleasure. I felt a bit stupid afterwards that I didn't show you a chip under the microscope.
 
user218912
@Obliv that's like exactly the same situation as me :p
 
user218912
except for the moving on part
 
I hope all the diagrams were helpful and that at least seeing the cryostat was interesting :D
 
@obe just let lady nature guide you instead of human girls. They're overrated anyway.
 
@DanielSank, it was all incredibly helpful and interesting! =D
@Obliv ...
 
user116211
6:21 PM
@Obliv lady nature?
 
user116211
What's that?
 
What is this, relationship venting hour?
 
@Obliv Uhhh...you're sounding like the guy in this xkcd
 
user116211
@DanielSank Obe's falling love story.
 
@MAFIA36790 aha
 
6:22 PM
@DanielSank More like no-relationship venting hour, I think :D
 
user218912
@MAFIA36790 failing*
 
user116211
No falling.
 
@ACuriousMind Well, indeed.
 
wow rekt.
 
@obe, I don't suppose the multi-person thing would work out?
 
6:23 PM
@MAFIA36790 richard feynmann and (probably) other old male physicists referred to nature as a she for some reason.
 
user116211
Iraq Army is in Mosul.
 
user218912
@heather it did once
 
@obe, but not now, I'll assume.
 
@Obliv Nothing to do with Feynman or physicists, the mythology of Gaia/mother nature is millenia old.
 
user116211
@Obliv Yes, Mother Nature.
 
user218912
6:25 PM
@heather nope, but she did sit beside me once by her own free will. :p
 
@obe, progress, progress =P
 
user218912
following acm's advice I will not overthink that.
 
user116211
@obe yes.
 
@heather Are you recommending obe have multiple girlfriends?
 
@DanielSank lol
 
user116211
6:26 PM
Don't be desperate.
 
Did you obtain information on how she sat next to you, though? @obe crucial information
 
@DanielSank, uh, no? Wait, what? I missed a couple hours of this, did something happen?
 
user218912
no she's saying to go out with friends.
 
user116211
There are other important things to do.
 
if she leaned in, angled her legs towards you, etc.
 
user116211
6:27 PM
@Obliv Angled her legs?
 
user116211
WTH is going on?
 
@heather He has no context and "multi-person thing" does sound like what he said without knowing what you actually proposed :D
 
user218912
@Obliv whoops I forgot to check.
 
user218912
was dying of nervousness
 
user116211
@Obliv, you seem to have researched greatly on female behaviour.
 
6:28 PM
@ACuriousMind, yeah, makes sense now in retrospect =D
 
My major was originally female studies @mafia
 
user218912
xD
 
user116211
...
 
with a minor in pick-up art.
 
Welp, I'm thoroughly confused.
 
user116211
6:29 PM
@DanielSank I'm sick right from the beginning.
 
@MAFIA36790 Sick?
 
user116211
huh.
 
I only understood a small portion of this anyway =)
 
@heather Decided on a science fair project?
 
user218912
what's unclear?
 
6:30 PM
Also... how do you have so much time for chatting? What about school?
Home schooled?
 
user218912
@DanielSank probably brings laptop to class since she won't learn anything anyway.
 
user218912
I did that.
 
@DanielSank, not homeschooled, rather, on the way back home currently so missing a day of school. I have around 5-10 minutes now, and then after around 30 min another 2 hours minimum.
 
@heather Makes sense. Was your CA trip good?
Did you like Santa Barbara?
 
@DanielSank, fabulous, Santa Barbara is great! Plus, nice weather =)
Haven't decided on science fair project yet, still thinking about and researching the various ideas I have.
 
6:32 PM
groovy
 
yup
life is good right now
 
reading through the last ~20 min of this chat is a serious argument for pushing up the female quota in physics o_o
 
user218912
@Sanya why?
 
@Sanya "pushing up the female quota..." wtf?
 
6:34 PM
"quota" - ?
 
I highly doubt that's what you meant to say.
 
^
 
vzn
@DanielSank hi wondering did heather drop by your lab as discussed awhile back?
 
@vzn yes
 
@vzn, yep
 
vzn
6:34 PM
@heather whatd you think? did you write any in here? missed that o_O
 
@DanielSank I guess that was bad english then ...
 
vzn
@heather cool, ofc dont forget computer science wink :P
 
"trying to increase the amount of female students among physics students"
 
@vzn, it was so wonderfully awesome and informative...man, that was just about the best day I've had in my few years of existence =)
 
user218912
@Obliv didn't see this message, this is exactly what I'm doing.
 
user218912
6:35 PM
so I'm on the right track xD
 
@heather WHAT?!
 
vzn
@heather :) how long was the tour anyway? did it include lunch? juicy details etc :P
 
:D :D :D :D
 
user218912
@Sanya how is that related though?
 
@DanielSank, why "WHAT?!" - of course it was awesome! =D
 
6:36 PM
@DanielSank What does that mean to you? It's clear to me what it's supposed to mean, and I'm not sure what disturbing meaning it has to you
 
@ACuriousMind A "quota" is a minimum required number of a thing.
 
@vzn, around an hour and a half, no lunch (I had some w/ my dad before going), but I got lucky, one of the dilution refrigerators was open so I got to look inside =D That was pretty cool.
 
@obe maybe it's only related in my mind ... but it reads like a lot of overthinking
@DanielSank so the ... share? proportion?
 
It can also mean a fixed, i.e. limited, amount of a thing which to which someone is entitled.
 
vzn
@heather huh, youre not talking about liquid helium are you?
 
6:38 PM
@DanielSank Always? I know it's used as such often, but can't it just mean 'ratio' or 'proportion'?
 
@vzn, liquid helium is used in part of the refrigerator, yes
 
@ACuriousMind That's a very lazy use, employed by people who don't want to bother to use the right words (IMHO).
 
helium-3 and helium-4, liquid in the bottom portion, gas in the top portion, plus some liquid nitrogen to get things down close to abs zero
 
@heather "...just about the best day..."
:D
 
@DanielSank, definitely =D
 
6:39 PM
@heather Nitrogen gets us down to ~70K.
 
I have to go for about 30 min, and then I'll be back
 
The helium compressor gets us to ~3K.
 
user218912
what is done at DS's lab?
 
o/
 
@DanielSank 'kay
 
6:39 PM
Then the circulation of 4He and 3He gets us to 20mK.
 
@DanielSank, right, I forgot the exact number, but it gets close and then the helium brings it the rest of the way down, right?
 
user218912
I also work in a lab but it's a nanotech lab, how does it compare to yours @DanielSank
 
@obe How could I possibly answer that without knowing more about your lab?
 
user218912
in general :p
 
6:40 PM
@vzn Hahahaha Charles and Pedram are strutting their stuff in that photo.
 
user218912
what is yours?
 
vzn
@heather darn was wondering about other details :|
 
user218912
@Danu \o
 
By the way, yes, I do TeX notes.
This semester, I'm even live-TeXing :)
 
user218912
it's useful right?
 
vzn
6:41 PM
@DanielSank while you are working feverishly in a dark back room right? was any of heathers family there too? wondering what any of them thought
 
@obe extremely.
 
user218912
I feel like it helps you narrow down exactly what you know about a topic which is everything in your notes.
 
user218912
but when you don't take notes you don't know/are not confident about what you know
 
user218912
maybe?
 
@vzn I'll let heather answer that, as it's personal information.
@vzn Our rooms are not dark.
 
user218912
6:43 PM
@DanielSank laser room?
 
user218912
it's always dark af when ur measuring stuff
 
@obe We don't use lasers.
 
user218912
oh
 
@DanielSank Tsk, what kind of physicists even are you if you don't use lasers? ;)
 
@ACuriousMind The kind who don't have to work in dark rooms.
 
6:44 PM
Theorist? :D
 
vzn
@DanielSank ?!? surprised! dont you excite the atoms with lasers?
 
Oh, hey, @ACuriousMind, I opened the last bottle of mead from my last batch. It was almost two years old. That batch was pretty gross at first, but that last bottle was very good.
@vzn What atoms?
 
WHAT ARE ATOMS
 
user218912
wait you don't work in ultracold atoms?
 
@vzn have you actually read any of the papers you send us links about? ;)
@obe No.
 
6:45 PM
Please continue to ignore me :P
 
@Danu ?
 
vzn
@DanielSank awww man, thought your qubits were atom based, now have to go look up details since youre mad :(
 
@vzn What the hell?
 
user218912
@DanielSank quantum a.i. lab???
 
1. I am not mad.
 
user218912
6:46 PM
what is quantum a.i.
 
2. Why do you use so many frowny faces here?
 
vzn and quantum physics
 
3. It is kind of funny that you've sent so many links to our work but don't know what physical system we use.
 
Can anyone decipher this:
> Hahhahahah bhai dekho ye sab kuch jhooth hai aur ye griffint bhai bhi jhoota hai is ki mat auno wo book bekar hai mai aap ko jo bol raha hoon us par amal karo aur ye log jo answers de rahe hai ye log bhi kuch nahi jaante hain bas tumhari maar rahe hain is liye ye sab chodo aur jaa kar so jao
 
no
 
6:46 PM
@obe AI = artificial intelligence
 
user218912
@DanielSank I didn't know :p
 
user116211
It's in Hindi.
 
vzn
@DanielSank yeah, unforgivable, youll have to rule me out from any future employment over there, but hopefully am not banned from tours also :(
 
no shit :P
 
@MAFIA36790 Aha, what does it say?
 
6:47 PM
@vzn More frowny faces... Anyway, you can tour any time.
 
I'd be (mildly) interested if this is offensive or just someone failing to communicate in English
 
@ACuriousMind you didn't realize? :P
 
user218912
@DanielSank I'm asking what quantum a.i. is
 
user218912
I know what quantum mechanics is and what a.i. is
 
@DanielSank Why don't you like his frowny faces?! :(
 
vzn
6:48 PM
@DanielSank (yay, thx!) its nice how hard you ding me on my lack of knowledge but dont volunteer the correct answer :(
 
@Danu I have no idea how Hindi looks or sounds, no
 
@vzn We use electrical circuits as our qubits.
 
vzn
am aware you were working with wafers.
(guessing) quantum dots?
 
@ACuriousMind Hmm
Somehow seemed obvious to me
Now that I think about it I don't know why.
 
@Danu ha
 
6:50 PM
Yeah, weird huh
 
user218912
@Danu maybe you're indian :O
 
Perhaps you were a speaker of Hindi in a previous life and accumulated enough bad karma to be reborn as a Dutchman :P
 
user116211
> See, brother, everything is lie and this Griffiths is also a lie; don't listen to it; it's a waste. Pay heed to what I'm saying. Also those people who answered here don't know anything; so leave all these and go to sleep.
 
Lol
 
Lol offensive confirmed.
 
6:51 PM
@MAFIA36790 'kay, chose the right flag then. Thanks
 
@ACuriousMind No offense intended to anyone, but do you really think being Dutch is bad karma as compared to Indian? :P
 
Rekt
 
@Danu That wasn't meant to be a serious statement in any form :P
 
OK :)
Because that'd be a case of [citation needed]
 
@vzn ::crickets::
 
user218912
6:53 PM
@Danu lol i'm pretty sure some ppl here just got offended
 
user218912
should delete that :p
 
@obe Statements that start with "no offense intended" tend to have that effect :P
 
@Danu The Dutch do have a somewhat unique reputation internationally...
India seems known for a rather friendly people.
 
@DanielSank Right, right... But it ain't all bad ;)
@DanielSank lol
 
you should all try being german before you claim indian or dutch were anything bad :o
 
6:54 PM
I'm half-German, also ;)
 
@Danu I mean, it's kind of funny, but it's tiresome to me that vzn frowny-faces me into oblivion and then whenever I try to actually help he bails out.
 
Help, this funny chat is distracting me from doing basic math on $[0,1]$
 
@DanielSank ::frowny faces intensify::
 
@Danu Ask @BernardMeurer about his German. Seriously, do it.
 
@DanielSank Why?
Also, you already did with that ping.
Tell us about it, Bernard.
 
6:56 PM
@ACuriousMind Close browser tab.
 
@DanielSank Yeah, I know I can do that. It's not urgent, I just didn't expect that checking this claim would devolve into pushing a lot of 0,1,1/2s around and not much else.
It's surprisingly boring :/
 
@ACuriousMind Wanna help my math?
Do you know what Stiefel-Whitney classes are? And how Milnor & Stasheff treat them axiomatically at first, maybe? (easy to look up)
 
Bye, everybody.
 
Bye @DanielSank?
 
@Danu I know what they mean, but not much else, and not their axiomatic treatment
 
7:01 PM
OK. Never mind, I guess.
 
7:16 PM
Finally, integrability lectures!!!
 
7:32 PM
I am doing the most important task of theoretical physics research
I'm printing papers on the topic so I can read them on the can
 
anyone know why spectral radiance tends to 0 for very high frequencies?
 
user116211
WTH!
 
user116211
Today is the birthday of our very chatroom!
 
user116211
Well, the first words were spoken in Nov 3, 2010 at this same time.
 
and what were they
" Welcome to chat for: Physics "
 
user116211
7:37 PM
Nov 3 '10 at 19:33, by Feeds
Welcome to chat for: Physics
 
Short and to the point
 
user116211
WoW, Happy B'day The h Bar ;))
 
vzn
8:12 PM
@DanielSank your qubits are made out of crickets? thx for the clarification :P
 
what are the odds that a non-responding microsoft word will recover information if i close program?
I'm going to be really mad if it doesn't..
 
user218912
@Obliv it normally does
 
user218912
what version?
 
It lost 10 minutes of work but that's okay because i didn't write much during that time.
it's 2016
 
user218912
k
 
8:19 PM
okay, I'm back
@vzn: the qubits are superconducting qubits, made by using a variable inductor and a few other parts, and then coupled using a capacitor. Just search superconducting qubits and that should help =)
 
vzn
@heather thx for clarification :) ... did your family see the lab also? what did they think?
 
@vzn, just my dad - he thought it was pretty awesome, obviously. He knew a bit more than I did about it because he has a background in lab work and such.
 
@vzn heh
@heather You have a good memory!
 
8:36 PM
@DanielSank, quick question:
 
::perks up ears::
 
if you have a calculation that takes a small fraction of the coherence time of the qubits, does it still need to be error corrected? If so, can you just run the calculation multiple times without specifically adding separate qubits to do so, and take the majority result?
 
Well, first of all, there simply are not any useful calculations that take a fraction of the coherence time. At least, not that we know of.
If there were, then you could just do as you say.
The closest to what you're suggesting that we know of is the experiment I mentioned where we think we can make the system do something not simulatable on a normal computer.
However, that's not the same thing as solving a useful problem, e.g. factoring numbers.
 
vzn
@heather cool so were you visiting family also in CA?
 
It's interesting to think about this. For example: can you simulate the motions of all the atoms in a bucket of water on a normal computer? No. Does that make a bucket of water a useful computing device? No.
 
8:40 PM
Yeah, I've been trying to think of a problem that would show the benefit of a quantum computer over a classical computer, and I'm trying to establish the boundaries.
 
@heather That's a great thing to think about. It's the sort of discussion we have in the group.
 
@vzn, no, my dad had business out there.
 
@vzn Heather's dad is a bad@$$ engineer.
He mentioned something about a twelve layer circuit board project o_O
 
24, i think
 
vzn
@heather what company does he work at? does he do optical stuff lately? you mentioned optics once iirc
 
8:42 PM
@heather Wat?!
Really? That's insane.
Your dad's really cool. Tell him I had fun meeting him.
 
vzn
@DanielSank there was a video circulating recently of a domino computer. etc.... computation is a remarkably broad phenomenon in some ways...
 
I found a source that said coherence times on superconducting qubits can go up to 100 microseconds - how many, say, swap gates can be done in that time frame?
 
@vzn Indeed. I have seen a video of someone who built a mechanical computer in Minecraft.
 
"Go to hell you elitist prigs!" --- another satisfied customer! physics.stackexchange.com/questions/290642/…
 
So there you have an electronic computer simulating a mechanical one via a physics engine o_O
@AlfredCentauri I really hate it when that happens.
 
vzn
8:45 PM
@DanielSank heather is a minecraft fan, have some around here too :)
 
Even if people find that their question is unfit for this site, I am dismayed that we should bring out such angry feelings.
 
@AlfredCentauri I can't see any deleted comments on that post - is that comment a reaction to the downvotes?
 
@DanielSank, I know my dad had a lot of fun, and he told me that he thinks you're pretty cool too =)
 
vzn
@heather afaik multilayer chips are close but not yet a reality... so thats not a chip right?
 
@vzn, what isn't?
 
8:46 PM
@vzn Huh? Dude your CPU is a multilayer chip.
 
^
 
vzn
@DanielSank uh this is not easy to explain (presumably you know this) but there are not multiple layers of ICs yet. there are layers for the interconnects.
 
@vzn Ah.
 
@DanielSank, just to get an idea of what coherence times are, I mean.
 
@ACuriousMind I saw the question just a few minutes after it was posted. It had earned one downvote and the OP had already posted an irate comment. I downvoted and voted to close and then the OP wrote his second comment and then deleted. I don't think there were any other comments.
 
8:48 PM
@heather Which message is that supposed to be a response to?
 
4 mins ago, by heather
I found a source that said coherence times on superconducting qubits can go up to 100 microseconds - how many, say, swap gates can be done in that time frame?
 
vzn
@heather so did you get to the beach at all or any other fun stuff?
 
@vzn, yup, such nice weather =) walked around, went to the beach, just soaked up the sun, all that good stuff
 
@AlfredCentauri Oh, well
 
8:50 PM
@heather Eh... say a swap takes ~20ns or something like that.
BTW @heather you might find the first chapter of my PhD thesis answers a lot of these questions!
 
oh, okay, thank you
 
I wrote it specifically for people like you: folks who know science but not the physics of superconducting qubits.
My uncle, who is not a physicist, said he found it very understandable!
 
@DanielSank, okay, I will continue reading through it then, I started it, and then got busy =)
 
vzn
@DanielSank wondering how are your qubits different than "quantum dots"?
 
@vzn Totally, completely different.
Our qubits are literally LC oscillators.
 
vzn
8:52 PM
isnt a quantum dot basically highly isolated electron(s) or something...?
 
@vzn Sure.
 
Quantum dots (QD) are very small semiconductor particles, only several nanometres in size, so small that their optical and electronic properties differ from those of larger particles. They are a central theme in nanotechnology. Many types of quantum dot will emit light of specific frequencies if electricity or light is applied to them, and these frequencies can be precisely tuned by changing the dots' size, shape and material, giving rise to many applications. In the language of materials science, nanoscale semiconductor materials tightly confine either electrons or electron holes. Quantum dots...
 
That's not even remotely similar to an LC oscillator.
 
vzn
reading that maybe a quantum dot is a small aggregate of atoms?
 
@vzn I'm confused by whether or not that sentence is a question. If it's a question, I'm not sure what it's asking.
 
8:58 PM
@DanielSank, another quick question, when you were talking about the magnetic moments that interfere with the qubits, are the magnetic moments resulting from impurities or inherent to the aluminum itself?
 
@heather We don't really know 100%, but we're reasonably certain it has something to do with oxygen molecules on the aluminum surface.
This is a big, very important outstanding problem in our field.
Magnetic flux noise is such a big problem that several groups design their qubits around the problem. In essence, they forgo the ability to tune the qubit frequency with magnetic field just to avoid the problem of frequency fluctuations from the spins.
 
vzn
@DanielSank ok you forced me to find a good ref/ survey which outlines basics (eg table 1) but which also examines hybrid approaches :) arxiv.org/pdf/1204.2137.pdf
 
@vzn Very good.
 
WAIT
Do I really need to bother all that much to prove whether or not a system of Alcubierre bubble has closed causal geodesics
After all, there are only two classes of geodesics
Geodesics inside and geodesics outside
since the inside of the bubble is isolated from the outside
 
Bye, everybody.
 
9:08 PM
@DanielSank, thank you for your help!
 
Many of you helped me solving this difficulty a while back but I am still stuck.
 
vzn
@DanielSank ok any news on Riedel (as guest)?
 
We have Einstein Equations. We solve them to get the Riemann Tensor. If we are really solving it, i.e., computing it then we will get some numbers as the components of it and we will have adopted a frame already. Now, let’s assume they are all identically zero. Correspondingly, we will get the components of the metric to be completely Minkowskian
Am I correct until now?
 
Yes
 
Now, I am using standard GR and thus, using the Levi Civita connection. This will give me all of my connections (i.e., Christoffel symbols) to be identically zero. Now if the spacetime is flat then I will have all the components of the curvature tensor zero- no matter what coordinate system I use. Shouldn’t this imply that I will always get the same Minkowskian components of the metric no matter what coordinate system I am using?
 
9:16 PM
No.
The metric you get from the Riemann tensor is only defined up to a diffeomorphism
 
@Dvij The Christoffel symbols of the Levi-Civita connection are not identically zero if the metric is not flat, and may even be non-zero if it is flat (polar coordinates)
 
And the christoffel symbols can be non-zero for a flat metric
Even if it is flat
For instance, Rindler space
 
diffeomorphism between?
 
Or the rotaty one
 
@Slereah What kind of example is that, just go to polar coordinates in flat space, it has non-zero Christoffels :P
 
9:18 PM
That's the most boringest one
Plus it's not a Proper coordinate patch
It has a coordinate singularity
 
Yes, I do know by calculating the symbols from metric that different metrics for the flat space gives different kinds of symbols
 
If you try to solve $R_{ijkl}[g_{ab}] = 0$ for $g$, you won't get a unique solution
There's a "gauge freedom"
You need to fix it by fixing the coordinates
 
But when I think in the direction that there should be a unique way of determining the components of the metric from the components of the curvature tensor, I am confused. Because, when I admit some particular subscripts, ain't I restricting myself to a particular coordinate while calculating the components of the curvature tensor itself?
and if that coordinate system has been selected then what more am I selecting while selecting the components of the metric?
 
Can you guys derive Schwarzschild in your head, as in all the Christoffel's, the curvature equations, and solving them, in both common notations, $A$ or $e^{\nu}$?
 
cf also
In general relativity, the laws of physics can be expressed in a generally covariant form. In other words, the description of the world as given by the laws of physics does not depend on our choice of coordinate systems. However, it is often useful to fix upon a particular coordinate system, in order to solve actual problems or make actual predictions. A coordinate condition selects such coordinate system(s). == Indeterminacy in general relativity == The Einstein field equations do not determine the metric uniquely, even if one knows what the metric tensor equals everywhere at an initial time....
@bolbteppa No you madman
 
9:23 PM
Yeah, I have it down to an A4 page :\
 
9:45 PM
@ACuriousMind, could I talk to you about mod type stuff, or is now not a good time?
 
@heather You could
 
@ACuriousMind, okay. Basically, it has to do with the new site.
It isn't completely finished yet, but it is at the point where a decent number of features are up and running.
And I was wondering if there would be a good way to start migrating some of the closed homework questions that are on topic at the new site to there.
 
@heather Well, it won't be "migrating" because you aren't part of the SE network. What you can do is copy those posts from physics.SE with an attribution link, similar to how PO "imports" SE questions.
 
@ACuriousMind, huh, for some reason I thought there was a "quick" way to do it without purely copying and pasting (with attribution link, obviously).
But I guess, are you guys okay with that? And would you ever want us to contact you when we get a "too conceptual" question that would be on-topic here?
 
@heather Well, I think PO has a script for that (i.e. there isn't someone copying and pasting the questions manually), but I know no details
 
9:50 PM
@ACuriousMind, oh, okay; do you think they would be willing to share that script?
 
@heather I can't speak for the community here, but I see no problem with that, especially if the questions are closed here. You might want to announce this idea on our and your meta to get broader community feedback
 
@ACuriousMind, alright, I will, seems like a good first step =)
 
@heather I don't have the slightest idea, you'll have to ask them
 
@ACuriousMind, okay. Well, I think that's everything. Thanks for your help!
 
np, I didn't even do anything ;P
 
9:55 PM
=D
 
@ACuriousMind if you just see cohomology with no field or type specified, what should I assume it is?
 
@0celo7 integral or real
 

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