« first day (2724 days earlier)   

12:06 AM
@G.Bergeron (1) It already means something else in topology, i.e., a locally flat submanifold N of a manifold M is something which admits charts (U, U \cap N) homeomorphic as pairs to (R^n, R^k)
(2) If you want to say a curvature vanishes at a point p of a Riemannian manifold M, you can just say it's "flat at p". (3) "Locally something" is usually used as an adjective for something which has that property "something" for some neighborhood about each point: but if the curvature is locally zero everywhere it's globally zero so just "flat" suffices.
 
@BalarkaSen And that is essentially the meaning I had for that terminology in mind...
@BalarkaSen Oh, not exactly, I would have used the term to describe a smooth part of a manifold, that is, it admits a diffeomorphic chart from an open set around that point to an open set of R^n...
 
Pretty much everyone has that in mind, except insane physicists like @JohnRennie who uses "locally flat space" instead of "manifold"
 
@BalarkaSen *smooth manifold
 
Oh great so you're an insane physicist too
 
@BalarkaSen Why the hell would you refer to some topological property as ''flatness''
 
12:19 AM
It's a topological property of an embedding. A locally flat embedding is one which locally looks like the embedding of R^k in R^n
That's "flat"
 
I also don't understand the comment, because what you wrote as your definition of flatness is also a topological property, not a geometric one
 
These expanding BEC donuts may provide ideas on thinking about cosmological expansions
 
Smoothness of a manifold is totally a topological property
 
@BalarkaSen And what if that smoothness is only local?
 
12:21 AM
if we want to go back further, we need to think about how space time emerge from a background free state
 
@G.Bergeron Again, that doesn't make sense per se. If you want to say your manifold M admits a smooth chart at a point p, just say it's "smooth at p". If you want to say your manifold admits a smooth chart at every point p, that's just the same as saying "M is a smooth manifold", so the "local" adjective becomes redundant.
Now, you can have the situation that there is an equidimensional open smooth submanifold N of M (i.e., "the smooth bit of M"). I'd hardly call that that's equivalent to "M is locally flat/smooth/whatever"
 
@BalarkaSen I'd a agree with saying ''smooth at p''. But local refers to anything you can construct on some neighbourhoods of the points around which that thing is to be constructed.
 
Well, relaxation can heat things up along the way as energy get transferred while fulfilling certain constraints
It makes me wonder what happens for potential energy surfaces with the reaction path moving downhill and passing through a saddle point of very high entropy, will it get stuck?
 
@G.Bergeron I generally parse "X is locally P" as "X has the property P at some neighborhood of every point in it's domain"
 
12:30 AM
@BalarkaSen Fair enough, our disagreement might stem from the (maybe abusive) use of the term ''locally'' even when there are (for instance) a measure zero set of points where the property in question does not hold.
 
Yeah
I think I'd use "generically" for that.
"M is generically smooth"
Or, better, smooth almost everywhere :P
 
@BalarkaSen Or, ''almost everywhere'' :P In the case of the measure zero exceptions
LOL
 
Sniped
 
Anyway, gotta run to the grocery store. See you later
 
Talk later!
 
12:44 AM
As the lesson goes: The best way to attack a pretentious spy is to grab someone who is good at attacking oneself
 
 
1 hour later…
2:14 AM
Today was a great day! I acquired a new contract like a boss
!! hehe
 
2:32 AM
and it does not exist
Voluminously
Because of this, I don't exist and has no physical form
A nonexistent existence is the most metaphysically powerful thing in existence that does not exist
But it does not matter if the above sentence does not exist, because it doesn't
15 hours ago, by 0celo7
@YuzurihaInori biggest load of crap I've heard all day
9 hours ago, by John Rennie
I wonder if it's possible to ignore yourself ...
It follows by the Luden Lemma, there exist a set of the form:
$$\text{Spherical cow} = d(x,y,z) \int^{\int^{\int}}e^x dx\frac{4i}{\pi^6 Gmc}$$
For more details, refer to the Handbook of Nonexistent Figments of Unimagination
thank you
 
hehehehehe
 
@Secret WTF ?!?
 
I spillrandom crap whenever I am annoyed about something in the chat that happens moments before the crap is spilled
 
Nothing really happened for 1 hour
 
Mar 24 at 16:47, by Balarka Sen
Who writes what he's doing on a regular basis on the chat to an empty audience
Mar 24 at 16:48, by Semiclassical
I usually can't understand Secret but at least he says interesting things.
Mar 24 at 16:48, by Balarka Sen
If he makes his "idea-blogs" shorter to fit in the context of chat, I think he's a perfectly fine member of the chat
Mar 24 at 16:49, by Semiclassical
There's a limit, of course.
actually I might considering pressing that button... at the cost of being extremely annoyed at the message discontinuity in the future
On an unrelated note, I am not fully nonsensing because I did proved that integral in math chat to go to zero (assuming I can actually resolve the tetration in terms of exponentials)
 
2:56 AM
@Secret I don't recognize the notation...
 
Well, I kinda wing it, not sure if I can actually define it this way...
in Mathematics, Mar 25 at 9:12, by Secret
where $\int^{\int^{\int}} = e^{e^{\int \ln \int}\ln \int}$
Since $\int$ is a linear operator, I should be able to exponentiate it, the main trouble is whether it make sense under ln
suppose we can do so, then expanding the whole thing into sums eventually result in a series of cancellations and then this integral operator then evaluates anything to zero
(which details are in the math chat link above if interested)
Personally, that notation is wrote as a joke, but then I went curious and wonder if I can define it so that it make sense, we also discussed about exponential maps of linear operators some days earlier
 
Hello h Bar !
 
$e^{\int}$ meanwhile should be well defined (up to a constant) since any integrable function is going to converge to some integrable function after being integrated, and its exponentiation is just some power series of integral operators
 
Okay so I read somewhere that a thermally conducting rod with higher $K$ (Thermal conductivity) absorbs negligible heat and conducts / transmits nearly all of its heat whereas its the opposite for a body with low $K$ . Now , since heat absorbed will cause the body to increase its temperature , can I say that bad conductors of heat get relatively hotter as compared to good conductors of heat (When same temperature difference is applied ) ?
 
I think if you plot the heat map of a conductor, you might see localised hot spots for the bad conductor, and the cold end should stay pretty cold
Likewise, for a good conductor, the heat map should look like a smooth gradient since the heat is being conducted quickly, thus evening out any local hot spots
I am not terribly sure if my intuition is correct, however
 
3:09 AM
Does my statement look correct to you though ? It makes sense to me , but not when I take an example and try to prove it.
 
The heat equation suggests when $\alpha$ is increased, heat will diffuse to a wider area at shorter time, so the average temperature of the object should be lower
$\dot{u} = \alpha \nabla^2 u$
so a good conductor should felt cold since the heat is quickly transported away from the hot object
 
Oh okay , hmm got it
but lets say I have a straight metal rod.
 
@Tanuj Anything has to get hot to ''conduct heat''
 
if K is high , the end away from the heat source will be hotter than the end away from the heat source in case when K is low , right ?
 
@Tanuj It is definitely NOT like an electric current
 
3:14 AM
@Tanuj yes, should be since the heat spread faster and to a wider area
 
@G.Bergeron Oh it is like electric current , why not do you think ?
 
@Tanuj It most certainly is not!
@Tanuj ''Thermal flow'' isn't really a flow at all. It's just high entropy energy spreading around to lower total entropy.
 
@Secret Okay , so what I get from this , if I observe certain sections of the rod nearer to the heat source , insulator must feel hotter since it absorbs most of heat + heat conducts slowly through it. And opposite for the sections of rod nearer to the end away from heat source.
@G.Bergeron But I derived all the formulae in analogy with electric current
 
I don't recall the formula for heat absorption, thus I am not sure
 
@Tanuj That's my point, this entire notion of ''heat conductor absorbing heat'' is not the proper way to look at it
 
3:17 AM
Okay , well thanks.
 
@Tanuj A volume of it gets hot, then the one next to it gets hot and so on.
@Tanuj What they are referring too is the heat capacity of a material, I think
 
@G.Bergeron yeah , so after a long time , insulator on being touched will feel hotter than a conductor , right ?
 
Which describes how many Joules of heat you have to dump in a given volume of material so that its temperature rises of 1 K
@Tanuj It depends of its temperature relative to your body
 
@G.Bergeron yeah so if lets say a temperature difference of 100 units is maintained .
Then ,
2 mins ago, by Tanuj
@G.Bergeron yeah , so after a long time , insulator on being touched will feel hotter than a conductor , right ?
 
For instance, you can play hot potato with your bare hands with a piece of coal (way above 100C) but try that with a 100C copper ball and the experience will be less than pleasant
@Tanuj Please be specific. Temperature difference between what and what. Which one is higher, etc.
 
3:22 AM
Oh okay . so that's a different aspect altogether. Copper being a good conductor transmits most of its heat to our hands.
 
@Tanuj They thought about heat that way back in the 19th century. See en.wikipedia.org/wiki/Phlogiston_theory Turned out to not work out...
@Tanuj And it has a much higher heat capacity than charcoal
 
our education system is outdated . Just by a few centuries though !
 
@Secret That is accurate
@Tanuj I was never taught heat was like a fluid, though.
@Tanuj Actually I think a teacher even mentionned this failed phlogiston theory back when I was in high school
@Tanuj But you seem to be mixing concepts. Any material, when conducting heat from an infinite object at temperature Ta to a finite reservoir at temperature Tb with Ta > Tb will have to reach Ta before heating reservoir B to Ta...
@Tanuj And the reason I said an electrical analogy is flawed is because electrical potential is a form of energy with very low entropy while heat is a very high entropy one. Thus, any real material conducting a current will have losses which will show up as heat. But if the material is conducting heat already, it cannot really have losses (ignoring ambient atmosphere and radiative losses) as there is no other form of higher entropy energy state for these losses to go to.
On another note, this is why heat is almost always what energy losses in system becomes (wether mechanical, electric, chemical) as it often is the highest entropy state for that energy.
Short of spreading around to the environment, that is.
Any way, I'll go cook myself some quesadillas..
 
3:37 AM
Can anybody suggest some good online resources to learn about angular displacement/momenten/velocity ? I'm deeply confused by Holliday Krane Chapter 8, where they define vector omega = d(phi)/dt, without defining d(phi) properly (they only thing that they told about d(phi) was that infinitesimal angular displacement are commutative, that too in a super hand wavy way) (sorry from mobile no latex)
^ d(phi) means d(vector phi)
 
@AlexKChen I'm not sure of your level of mathematics. But from what it looks like, it's a differential of the coordinate $\phi$. Same as $dx$.
what's d(vector phi)?
 
Yeah (I'm in high school senior year)
 
@AlexKChen It might be helpful to look at en.wikipedia.org/wiki/…
@AlexKChen Sorry that, doesn't tell me much, I don't live in the USA.
 
That means 12th grade. No I don't understand for example for rotation around arbitrary axis, how you break d(vector phi) into d(vector phi x),d(vector phi y) , d(vector phi z) ?
 
@vzn I'm not that surprised since training on past behaviours is essentially reading out the initial conditions at more and more precision.
 
3:45 AM
You should be able to do that because they are vectors, right ? (Though I don't properly understand why except in a super hand wavy fuzzy way)
 
@AlexKChen what's vector phi?
 
See above
 
@AlexKChen -_- My point was that curriculum varies by country, but anyway.
@AlexKChen You did not specify what it was
 
Vector phi means "infinitesimal angular displacement vectors"
 
@AlexKChen That's probably d(vector phi)
 
vzn
3:47 AM
@G.Bergeron lol more sniffing? ML in physics is really new... and... uh... hate to say it... r e v o l u t i o n a r y :P
 
@vzn sniffing?
 
vzn
@G.Bergeron yes. oh let me find one of the many (other) examples of that...
 
@vzn I just don't know what you mean
 
vzn
Apr 16 at 5:24, by John Rennie
@G.Bergeron I am not convinced vzn is sincere. He has come into the chat room with news of amazing experiments that challenge conventional thinking more times than I have count.
sic :P
 
@AlexKChen It'd be quite helpful to actually give details about your question... Like: motion in a plane, what are the coordinates, etc. I don't have that book in front of my eyes
@vzn Still don't get it
It wasn't me that wrote tha
 
vzn
3:51 AM
@G.Bergeron sniff ... 4. to show disdain, contempt, etc., by or as by sniffing.
 
@vzn I'm not a native english speaker...
 
vzn
@G.Bergeron ok. thx for info. didnt know. will have to keep that in mind. didnt write what?
 
@vzn If that's what this means, then I definitely was not doing that, but rather genuinely reacting to what was posted
 
vzn
@G.Bergeron its a big deal™ but ofc others will say coulda figured that/ whatever... kind of a theme around here... many around here very jaded even bordering on nihilistic at times :| o_O
 
@vzn Why do you publicly ask for comments (if at least implicitly) only to wave off anything that does not fit with your seemingly pre-constructed conclusions.
 
vzn
3:55 AM
@G.Bergeron others wave me off, and feel free to reciprocate the sentiments/ (dis!) "favor" ... what comes around goes around :P
 
@vzn You seem to presuppose I don't have any knowledge about ML in physics, that I haven't thought about the topics before hand, discussed it with experts in the field, etc.
 
vzn
@G.Bergeron did not presuppose any of that. only reacting to your (unsurprisingly/ fitting around here) lukewarm comments. ps maybe you didnt notice the name of the researcher involved... deja vu for me at least o_O
 
@Semiclassical heard you've been slinging mud while I was away. You're a bad dog :)
 
@vzn My comment was my genuine reaction to the bold claim of going beyond the limiting aspect of Lyapunov exponents in chaotic systems.
@vzn The name of the author is not an argument about anything.
 
vzn
@G.Bergeron think the research is impressive to say the least and am disappointed that the only comment so far says (nearly) the opposite.
@G.Bergeron right. exactly. so will henceforth ignore your name whenever seeing it, and others can return that favor also :P
 
3:59 AM
@vzn The technical part is nice, the ML engineering and application aspect is really nice, but the bold claims challenging without basis foundationnal aspects of chaotic systems theory is what lukewarmed the whole thing. The article goes from nice to click-baity
 
vzn
@G.Bergeron right. real scientists™ hate "breakthrus".
 
@vzn I mean, you do realize how passive agressive you have been within all your interactions with me beyond the first few messages?
 
vzn
@G.Bergeron youre obviously very smart/ well read but you think just like all the rest of them. do you have some original thinking going on? think you should look in the mirror with some of your very disparaging comments. ps bolbteppa/ semiclassical/ others were involved in threads, and theyre all oppositional to some of my thoughts...
 
@vzn I do have original line of thought going on, that's the whole point of research, isn't it? But then I won't broadcast anything other then to close friends before I have anything rigorous, solid to say and before I have tried my best to find any errors and ask said friends to do the same.
 
vzn
@G.Bergeron ok. think thats a shame, think cyberspace has some potential for sharing new thoughts outside of papers. but its obviously your call/ perogative, and do attest its the "safer" route. its true, sharing my original thoughts here has brought me almost nothing but vehement objection and namecalling etc. (it seems at times...)
 
4:07 AM
@vzn That's because offloading thoughts on cyberspace is the easy part. Making everything rigorous well-defined and connecting it to the current body of knowledge is the extremely hard part.
 
vzn
@G.Bergeron agreed and other hand a newborn baby does not arrive fully formed and fully ready to face the world does it? you can see me struggling to add rigor at every moment.
 
The thing is, speculation is not original.
If anything, it's a dime a dozen.
 
^this
 
@vzn You seem to spend a lot of time telling people actually engaged in doing science how you think they should think
and go about what they do.
But ...
 
though my attitude is really more along the lines of: "If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them." (Thoreau)
 
4:10 AM
Have you actually done the spade work necessary to do some science yourself?
 
vzn
@Semiclassical lol luv thoreau, very poetic. if you keep quoting him in here others will likely complain at some pt :P
 
I somehow got more into Emerson than Thoreau.
Not sure why.
 
vzn
@dmckee another pov, spend a lot of time working on bold, sometimes verging on wild hypotheses/ conjectures that may be true. if they are true, then others should think about them also. science does not progress/ evolve/ advance by past textbooks ("alone").
 
@vzn And if they are true, then they're not conjectures anymore. For others to think about them, you first have to convince them it is true.
 
vzn
@G.Bergeron think you are wrong there. think that is part of the misconception. memes need to be developed. you are just seeing them developed before your eyes. yeah it can look messy. but science can be messy.
 
4:14 AM
As dmckee and Semiclassical said, when you spend time grounding your ideas in order to broadcast them, you realized a lot of stuff does not work out as expected.
 
It's also usually the case that conjectures, while not provable, have specific evidence and arguments behind them.
 
@vzn Scientific statements ought to be as little sociologically based as possible
 
vzn
am tired of everyone around here ****ing on very solid work by many other top researchers and not taking it seriously, dismissing it, tossing it aside if its not "fully complete". think this crowd would have tossed aside einsteins original papers in the same spirit. yeah whatever, its obviously not finished yet
 
@vzn I actually read the paper you posted!!
 
vzn
@G.Bergeron lol
 
4:16 AM
::facepalm::
 
I always go in new paper in good faith and follow along
But also maintain a critical view as I read, otherwise it's just blind faith
 
Do you think there is any possibility at all that people are simply concerned that you are running a wee bit ahead in drawing conclusions from what you read, maybe?
 
vzn
facepalm^2
yesterday, by G. Bergeron
@vzn Look, I don't hold a grudge. It's just the entire exercise seemed like a waste of time in the end.
 
I've seen the millennium announced a few times already.
 
vzn
@dmckee another pov, think if anyone comes up with a major new correct theory, apparently those in this room will be the last on the planet to accept it or discuss it positively
 
4:18 AM
@vzn Also, you have to realize the amount of claims we get all the time, by email, on this chat, in person, etc. I see it as a duty to at least consider seriously some of them. However, not a single one I checked personally turned out consistent.
 
I've seen the machine learning millennium announced twice before, though it appears they may have licked the actual hard problem for this go 'round.
 
vzn
@dmckee have seen ML go thru several "winters" also. cite the gartner hype cycle myself all the time. its as common as r e v o l u t i o n s. en.wikipedia.org/wiki/Hype_cycle
 
@vzn It was a waste of my time because when I pointed out serious problems with taking this paper as actually being about reality you entirely dismissed me and remained unmoved in your certainty, while never providing any rigorous counter arguments to what I brought forward.
 
vzn
@G.Bergeron new science™ is very hard
 
@vzn That would be a deffensible argument if you didn't have a new revolution to tell us about several times a week.
 
4:21 AM
@vzn Indeed, but you do not seem to see it like that...
 
vzn
@G.Bergeron the point is it can be advanced and think it will, by others more farsighted than those who dismiss it. time will tell.
 
@vzn And my honest opinion is that it's a dead-end.
 
@vzn B7t that us exactly what you are not involved in. You're jumping on every report you see of someone else's work...
 
vzn
@G.Bergeron do respect your opinion (bolbteppa + many others would probably agree). would like to work thru your objections at length (even more than already have done) but dont think you or anyone else really has the patience. have emailed the authors.
 
Anyway, those quesadillas I was about to cook will not cook themselves. I even have a whole chicken to butcher before that...
 
vzn
4:25 AM
@G.Bergeron anyway, am all ears if you want to share a paper on what you think is the best/ most viable/ promising GR + QM direction/ angle. at least we agree on "1" )( scientific priority.
 
@vzn Honestly stuff like that arxiv.org/pdf/1602.06987.pdf But I wouldn't be surprised if it didn't work out either, at this point.
 
vzn
@G.Bergeron digital physics™ eh? music to my ears :P
 
I'd rather say informational
anyway, see you people
 
My own bet is on resurgence theory...which is precisely not a bet on new physics, but on extracting more information from the physics we already have
 
@Semiclassical I would agree, but that is very general
 
4:30 AM
yeah
 
Anyway, it seems like we're not getting very high energy data any time soon, so yeah, next best thing.
 
vzn
@dmckee there are only a few revolutions in play at any moment but there are lots of events that tie into them. thinking that "none are in play" is a sign of static thinking. btw every revolution cited by me is cited by other top-credentialed scientists etc...
 
@G.Bergeron Yeah. If you can't find stuff which 'obviously' indicates some new directions, it behooves you to look carefully at what you've got and try to test it as systematically as possible.
Which is hard to do with systems at strong coupling
 
vzn
@Semiclassical you mean within QFT? ps would you care if resurgence theory was tied into soliton or hydro-dynamics somewhere? =D
 
I dunno. The problem with soliton stuff is that that requires knowing about integrability, and uh...I've never been good at that
hydrodynamics...maybe. not sure.
 
vzn
4:37 AM
@Semiclassical looking for keys under the lamppost... o_O :P
 
I can guarantee you guys that if you pay Netflix engineer type money to young scientists, within 10 years someone will solve it. Nobody can dedicate the amount of time and effort required to do this unless they decided to be single and poor.
 
36 mins ago, by G. Bergeron
@vzn I mean, you do realize how passive agressive you have been within all your interactions with me beyond the first few messages?
 
@Cows I am single and kinda poor! :p
 
vzn
@Cows actually do agree with you. think about the "incentive problem" a lot myself. did you have some experience with scientific research/ $?
 
@vzn I can definitely tell you that the only way I'd be publishing anything (and I am capable) is if I can convince a company or some rich guy to pay what I think is fair for the kind of effort, level-headedness, and commitment that it must take. Nobody should have to work for less than they are worth
 
vzn
4:42 AM
2 days ago, by G. Bergeron
@vzn Following your analogy, it's more like humanity is massively dumping swords and battlecruisers and atomic bomb in the fire and at an industrial scale and you just came up with a kitchen wooden spoon...
 
Trust me, if people were properly motivated, we will have an abundance of riches in terms of credible ideas with predictive power and computational ease
but physics does not pay as much as say cs
 
vzn
@Cows theres huge $$$ in AI/ ML, a very scientific field, did you see this? A.I. Researchers Are Making More Than $1 Million, Even at a Nonprofit o_O nytimes.com/2018/04/19/technology/…
 
pessimist that I am, that makes me wonder about whether it's a bubble
 
@vzn yes , generally cs graduates are making bank, and for good reason. These girls and guys are talented.
hehe :P
 
vzn
@Semiclassical lol (speaking of pessimism) facebook might be a bubble... :P
 
4:46 AM
might be. I haven't actually logged into FB in months that I can think of
Bitcoin is the big example I wonder about
I mean, other cryptocurrencies have flamed out
 
To be honest, mathematicians (some of them) make quite a bit too just not the ones doing research
Things are changing though
 
@Semiclassical I hope not! Still holding mine out!
 
yeah, industry jobs can be pretty good
 
@Semiclassical It definitaly IS a bubble. Ask any honest persons in the field.
 
Besides, I believe in myself. I know that when the time comes I'd go out and find some company or billionaire to fund me
 
4:48 AM
@Semiclassical Same as for physicist
 
I have to learn a lot first
 
so can math people who go out into finance, though that seems pretty soulless
 
I heard(from a recruiter) that finance people don't trust physics phd's anymore
 
I don't know if she was screwing with me
 
4:49 AM
wouldn't shock me tbh
 
They are back to hunting for either pure Finance or pure cs
It is hard getting a technical job in the real world
 
I study everyday, and for every 10-20 interviews I get one offer
 
I think physics phd programs don't do a great job of positioning people for life outside of academia
 
These are technical interviews and they don't care who you know or what you've done.
In each case there are about 40 other people sent by a few other recruiting agencies
You do your phone screening
do your skype call
 
vzn
4:52 AM
@Cows so why not take 1?
 
do your white board
@vzn I accepted a new contract today
Disney turned me down though
I taught CS for 2 days before that, and then quit
 
vzn
@G.Bergeron think not :P
@Cows cool/ congrats/ what?
 
yeah
I am a Sr. Software engineer at some company
yeah the students of the college had a hard time taking me seriously
hehe
 
vzn
@Cows btw think youd be good for this if you feel like it sometime :) physics.meta.stackexchange.com/questions/7783/…
@Cows what company? what tech? etc? (ofc feel free to not say)
 
@vzn yes, perhaps some time in the future hehe
 
vzn
4:56 AM
@Cows ok np theres no waiting line (sigh) :P
 
@vzn normally I will tell every one of the company but, you know how some of these companies have weird rules and stuff :P So I can't really on here.
 
I see the epic troll man is trolling again
 
vzn
@Cows yeah am aware of that. ok let us know as soon as you can or whatever you can say. think its cool how many top companies youve interviewed with... not easy to get those interviews... :)
 
@BalarkaSen who is the epic troll man?
@vzn yeah getting the interviews is not the problem. It's cracking the interview that is hard
 
vzn
@Cows 1/40!
 
4:59 AM
yup
 

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