The h Bar

enumaris

12:00 AM

I would if I have enough time

and enough motivation

but 1/2 is as much motivation as I could muster

imo it's actually pretty well written

it's just really freaking long

Cows

yeah from observing the convo, it seems you've gone pretty deep into these matters

I don't know how to read a text

I tried a few times and failed

I usually just end up trying to see if I can pick things up and then produce something close , and then ask for help

sometimes it works

also when I mentioned I read x, y or z

there is usually disbelief or something lol

at any rate , yeah those are some cool texts and topics

Is MTW big because things are computed in full, or because it goes through more applications ? or something else?

@enumaris what prompted you to go the route of ML, you seem like the ideal academia candidate

bolbteppa

It's big because they implanted hundreds of pages of formalism that can be avoided to try remove coordinates completely instead of just using coordinates and making sure it doesn't matter that you used coordinates the way humans usually think :p

Cows

oh hehehe :D

enumaris

I think they are 1. quite thorough, and 2. cover a ton of topics

They include a lot of formalism that wouldn't necessarily be useful in a first course on GR for example, but they wanted to be pretty complete

And they spend a lot of time trying to give some sort of "intuition"

danielunderwood

Isn't there also a bunch of supplemental info in the boxes? Like historical notes, applications, and such

enumaris

12:12 AM

yes

a lot of stuff like that too

@Cows dunno if I'm the idea academia candidate...lol

welp, time to go home :D

leave the problems I couldn't solve today for tomorrow

fun beans

Cows

lol

Secret

3:02 AM

sciencedaily.com/releases/2018/07/180709111148.htm

Nanowire become nonsuperconductoing as Cooper pairs break apart. May provide further insights to microscopic origin of loss of superconductivity

nature.com/articles/s41567-018-0199-4

A quantum heat valve to investigate heat transfer between qubits

nature.com/articles/s41586-018-0265-1

Strong equivakence principle passed test again now in the neutron star regime

arxiv.org/abs/1801.02669

So, we are saying that neutron star mergers generate gamma burst? Anyway, really glad to have gravitational waves to track these events

iopscience.iop.org/article/10.3847/1538-4357/aac725/meta

Simulation of the collision that tip Uranus on its side and keeping it cold is now done

Avantgarde

3:33 AM

Hey

France gonna win the world cup

Secret

Hmm...

sounds good

Avantgarde

definitely not coming home

Secret

advances.sciencemag.org/content/4/7/eaas9544

Getting closer to laser precision controlled chemical reactions

atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/…

Some W Z and W W scattering for study

Cows

5:06 AM

@Secret wow quite a bit in the news lately

Cup Fever

7:00 AM

@Avantgarde Croatia may have something to say about that...

I mean, the Croatian soccer team, of course :-)

DarkKnight

8:46 AM

What is association bonus ? I have got 100 reputations today as association bonus.

John Rennie

@DarkKnight this:

329

Q: What is the association bonus?

I was just awarded +100 reputation on all of my Stack Exchange accounts. What is this bonus for? It simply says "Association Bonus" on my reputation overview. Return to FAQ index

Cup Fever

My god, only 20 years old.

in FIFA World Cup, Jul 3 at 10:41, by Ram Chandra Giri

Messi 'super fan' commits suicide following Argentina's World Cup exit What's your take on this?

If the JEE doesn't get them, sports fanaticism will.

2

DarkKnight

9:37 AM

@JohnRennie Thank you for the information.

Emilio Pisanty

9:57 AM

gaudiest plot ever

in this is in the Science journal where you pay them to publish

wait, what?

Gábor Fekete died?

how did I not hear about that? and where did google get that information? what's a reliable source for that piece of news?

mta.hu/mta_hirei/…

or maybe there are two Gabor Feketes?

say, @dmckee, have you received any emails from the Gabe within the past eighteen months?

Anonymous

10:46 AM

@EmilioPisanty Why would a botanist bother to spam physicists? This is weird :P

user351417

I've heard people write about him like he's a joke, but I can't tell if their serious or not.

user351417

Anyways, if you trust wikidata, he died in 2016 wikidata.org/wiki/Q998075

Anonymous

@Chair Well, you have this :

Anonymous

mta.hu/mta_hirei/…

Rumplestillskin

Is anyone familiar with the "Binet" equation which describes classical Keplerian orbits? It normally takes the form $u''(\theta) + u(\theta) = C$ where $u = 1/r$. The presence of a term that goes like $u^3$ normally describes the GR analogue.

Well, my question is in relation to this. These equations are covered in every undergraduate course on Newtonian mechanics / motion in GR.. However, when it comes time to describing orbits; the above equations are ditched in exchange for the orbital element approach. Of course the advantage is due to the fact that one describes the shap of the orbit and the other allows one to describe the time evolution of the system.

However, are there any cases where using the usual orbit equations can be more beneficial?

I am doubtful

Emilio Pisanty

11:50 AM

@Blue I imagine they're two different people

@Chair it depends on what you mean by 'joke'

Gabor Fekete himself is (presumably) dead serious in his endeavours

though the results of those endeavours can look less than serious to everyone else

Akash. B

12:53 PM

Hi

Slereah

2:25 PM

You know I wonder how much I could write on 1-dimensional manifolds

it is an interesting topic

Secret

2:46 PM

BOMB

2

Q: How to define *dynamical* dimensions?

I'm considering a simple toy model. The spacetime is flat with $d$ space dimensions. Using cartesian coordinates, the spacetime metric is Minkowskian : $$\tag{1} ds^2 = dt^2 - dx_1^2 - dx_2^2 - dx_3^2 - \ldots - dx_d^2. $$ A massless scalar field $\Phi$ is propagating in that spacetime accordin...

general-relativity cosmology spacetime spacetime-dimensions topology

Jun 8 at 18:35, by Slereah

Saying that others are lost in mathematical abstraction

ok now where was I...

Secret

3:00 PM

dies

Cows

3:16 PM

At a campus event. I have cow and bull apparels, with horns and all. Hehe, lol. BTW wrote some super code last night. One of my all time best performance. So I am sitting at a table with people I believe can become super awesome if not already :P

Drinking OJ , eating cookies. I wore some strange edgy male apparel this morning. I was feeling weird so I figured eh why not lol

It has some cross laced looking fixation in the chest area. I was going to accessorize this with some strange looking gadget but eh.

Presumably I will be getting a school I'd later today, as a "matriculated student"

Who cares . . . All I want to do is take analysis so i can rub it in the faces of all those who said. . . "You should take analysis" lol. I should be straight forward :P as I have secretely eaten all the popular anal texts out there hehe

Ok, the event is about to start . Moooooo LMAO

Ohhhh here comes our mascot the bull(Toro) ahaha lolz lmao

This is fun hehehe

danielunderwood

Alright I either have a riddle or I'm an idiot. Say you have $\int_a^b f(x) \frac{d g(x)}{dx} dx$ if $g(a) = g(b)$, you have $- \int_a^b \frac{d f(x)}{dx} g(x) dx$. But say $g(x)$ is a constant. Then you'd have $0$ in the first case, but $g \cdot (f(a) - f(b))$ in the second case.

If it helps, this is coming from a version of Noether's theorem where you promote a global symmetry to a local symmetry to do a similar calculation, then set it back to a global symmetry at the end

Cows

3:44 PM

Vice Provost just gave a deep speech. Impressive!

Wow and now we are dancing! Yaaaasssss . Ok ok I dig this

Oh here comes the mascot hehehe

danielunderwood

@bolbteppa You linked me to the PI lectures a week or two ago. Any chance you know if they have the problem sessions available? I couldn't seem to find them on the site

enumaris

4:03 PM

weez

Semiclassical

4:26 PM

@danielunderwood integration by parts gives $$\int_a^b f(x)g'(x)\,dx = f(b)g(b)-f(a)g(a)-\int_a^b f'(x)g(x)\,dx$$

and in general you do have to worry about the boundary term

in a lot of physics cases, this boundary term is just zero. but it's definitely part of a generic integration by parts

danielunderwood

Ahh so it's that I was an idiot. For whatever reason, I was thinking that $g(a) = g(b)$ would make boundary term go away, but you'd need a condition on $f$ too

Semiclassical

right

often you'd require that one of them should vanish on the boundary, which makes things easy

danielunderwood

Well now I'm back to wondering why the calculation I saw in a lecture makes sense. Unfortunately I can't seem to find that version of Noether's theorem anywhere

Semiclassical

something-something boundary conditions

Danu

@BalarkaSen TFW Gauss died when Klein was 5 years old, doe

enumaris

4:42 PM

it ain't no thang

bolbteppa

5:17 PM

@danielunderwood Don't think they put those up

$\int_a^b f(x)g'(x) dx = \int_a^b \frac{d}{dx}[f(x)g(x)]dx - \int_a^b f'(x) g(x) dx = \int_a^b [\frac{d}{dx}f(x)]g(x)dx - \int_a^b f'(x) g(x) dx = 0$ if $g$ is constant

Run like hell

5:41 PM

Why can we see black holes merging? Shouldn't an observer out of a black hole see something crossing the horizon in an infinte time? So this time we have two horizon that are going cross each other, shouldn't we see that in an infinite time?

danielunderwood

6:16 PM

@bolbteppa Well that's disappointing. The lectures I'm watching now are pretty good, but he keeps referencing the problem session. They do have a couple online that have everything, but it's only QFT and condensed matter from what I can tell

And I don't think we actually see them. We just receive a gravitational wave signal that matches up to the simulated one. I'm no astro guy though

Cows

6:31 PM

Ok this is the consent part. Using cup of tea hehe but not so lol.

Tea is coitus. Ask nicely for tea, and don't make unconscious people drink tea

Wow . . lol

I definitely won't be asking for tea on campus :P

I liked how tea consent was presented. The presenters were reasonable and cool

Now they are talking about stalking. Very interesting. . . . .

Lol spyware etc too hehehr

I believe if one can build spyware, they are unlikely to deploy it on people in academia lolz

But serious stuff

So happy I have my tea needs met by my so. Also I will be spending minimal time on campus and reduce interactions to close to 0. Don't want to expose myself to any of this stuff lol

Secret

it dies not exist, nowhere does

and tea gets cold

and incomptrenhensible h bar not

Cows

Ok now we have a cop talking about safety hehehe.Should be interesting

Secret

none

Anonymous

6:48 PM

Are you again after Slereah? lol :P

Secret

Records said 2 outstanding questions, though the questions have became so amorphous it is not longer resolvable

thus you can say it kinda stuck in limbo

I am onyl doing that when the room is quiet, and not going to make a one page spam

so it can be disguised as a joke

I also did that whenever cows is speaking in radio braodcast mode

Anonymous

@Secret LOOOL

Cows

lol

Anonymous

"radio broadcast mode"

Anonymous

That fits it perfectly :D

Anonymous

6:52 PM

Cows' broadcasts are often interesting though ;)

Cows

So the cop speaking in now giving us the three actions. Run hide fight

Also a video available of some simple fight techniques can be available on a site hehe

Anonymous

@Cows Don't listen to the last one unless you're carrying a gun :P

Anonymous

(and your opponent is not)

Cows

@Blue yes, I think run and hide will be my preferred defence mode lolz

Ok now we have the mental health section

Psychological services

Confidentiality with caveats. Hehe ok ok nothing new here

So if things keep me up at night I should seek services. Might bring up a few integrals that haunt me at night lol. Jokes aside she is going through the process and the importance of the process. I might have heard wrong but I think the word medication might just have been used

Ok breaking for launch

I think we are grabbing subway sandwiches or something

Tight so will be getting ID card after lauch.

😁

Anonymous

What's this all about? New uni?

Cows

7:03 PM

Matriculated student here heading toward Subway sandwich and catering area hehe

Just took a photo and got my ID handed to me. Cool stuff.

Eating a Subway sandwich now. Then will meet my group downstairs for some more info

danielunderwood

I'd like to see a version of this where you actually need to redo all the physics half a dozen times because you didn't know enough math i.stack.imgur.com/ofzNL.jpg

Cows

7:24 PM

Hehe

Anonymous

@danielunderwood That one is worth bookmarking! Previously I only saw the first frame on xkcd I think

danielunderwood

I saw it linked on a question and it gave me a laugh

Anonymous

Which question?

danielunderwood

Well the one that actually linked it was this one physics.stackexchange.com/questions/9468/…, but there was a recent question that was more or less a duplicate of that one

Anonymous

Oh, it's from Abstruse Goose

danielunderwood

7:33 PM

A Witten to English dictionary could be useful though

Anonymous

Wouldn't fit in one room though ;)

danielunderwood

I feel sorry for people studying before the internet. I'd have to have so many more books to answer all my little questions

Mostly what does some strange math term mean

Anonymous

Apr 10 at 6:01, by John Rennie

Back in the 1970s when I was a 15 year old physics enthusiast the Internet didn't exist (hard to believe I know :-). I would have given my right arm for a resource like the Stack Exchange!

Anonymous

O:)

Anonymous

We live in good times

enumaris

7:37 PM

his face is missing a parenthesis

Anonymous

His lips are making up for it

enumaris

It don't work like that

danielunderwood

I will blame the internet for me not being in the library as much as I should have been as a student. Now I don't have a decent library less than an hour away

enumaris

I rarely ever visited the library lol

Anonymous

Libraries are still good places to study. Just that you have your laptop open instead of books, now

Semiclassical

7:39 PM

@Blue that's either a surprised person with a unibrow or a smiling person with a halo

enumaris

I went to the library at college twice for a group project

All the rest of the times was to go to sleep or something

have a seat

Anonymous

And the air conditioner!

Anonymous

At least here, people visit the library for the AC

danielunderwood

Yeah I didn't either. Pretty much the only times I went were for group projects. I did start going to the physics stacks and finding books that I found neat. Now I do the same with amazon and have a ton of books I'll probably never use

enumaris

crap, tableau is taking forever to calculate this filter...wtf.

I bought MTW the other day

I do want to read it

but I somehow doubt I will

lol

Anonymous

7:41 PM

The internet needs more high quality "video" lectures though

Anonymous

It's pretty difficult to find good lectures online

danielunderwood

I bought it back when they did a re-release since I always wanted it, but the original version was some ridiculous amount of money. I think I made it through a couple chapters before I thought I should probably learn more from a basic source though

enumaris

I can lecture you

Go do your homework!

MTW I find is pretty intuitive

good place to learn as a grad level

Anonymous

@enumaris That's not high quality ;)

enumaris

not great if you are new to physics probably

danielunderwood

7:43 PM

Yeah I agree with that. I wish there was something like brilliant.org for more advanced stuff. Although I guess at that point, you might as well just pick up a book and do questions

enumaris

sometimes doing problems can hinder conceptual understanding imo...in the sense of it taking you forever to get through lol

getting stuck on a problem for 3 hours probably doesn't really help you understand the theory conceptually much better...though there are times that you do get a deeper understanding in other ways

danielunderwood

I did start reading Zee's GR that I found interesting. For as far as I got into it, he seemed to do quite a different approach by defining groups and starting from the action. I got distracted by something else though

Semiclassical

well, you do learn things from such problems

it's just, you don't necessarily learn the right things :P

danielunderwood

I seem to have a problem of studying one book for a while then switching to another

Anonymous

@danielunderwood Everyone has that problem. That's because most books are terribly written!

Semiclassical

7:45 PM

lol

shots fired

danielunderwood

I mean I find some of the books wonderful, but I see a new shiny subject

Speaking of terribly written, you guys should take a look at this book smile.amazon.com/First-Course-Loop-Quantum-Gravity/dp/…;. I don't know that I would call it terribly written, but it claims to cover LQG starting from not knowing SR and it's about 100 pages long.

Like within 10 pages, you go from saying what a Lorentz transformation is to talking about Yang-Mills theories. I read through the whole thing and don't know if I managed to learn anything

@enumaris What would you say is a better way to gain understanding than working through 3 hour problems?

enumaris

maybe discussing with someone knowledgeable and clear on the subject

Anonymous

Discussing problems with other people gives you more understanding in most cases

Anonymous

Than trying it yourself

enumaris

like doing a 3 hour problem, if it's a 3 hour problem, might be worth it, but doing a 3 hour problem when it should be 10 minute problem is probably a waste of your time lol

Anonymous

7:49 PM

But then again you need to find someone interested enough

Anonymous

@enumaris Especially when it's something like an arithmetic error, which you have been missing for 3 hours

enumaris

sitting there trying to find a negative sign error or something also probably a waste of your time in terms of understanding

it might help your patience when you have to do it for real though...

danielunderwood

Well that's unfortunate since I don't really have anyone around me with much interest in physics, let alone the knowledge to discuss problems. Guess I should have done more of that in school

enumaris

but in terms of actually understanding a physical concept, probably entirely useless

danielunderwood

Is there anywhere that has like daily/weekly physics problems with discussion? I've seen similar for programming and such

Anonymous

7:51 PM

@danielunderwood So you're going for a PhD or masters anytime soon?

Anonymous

Or do you have any such plans?

Anonymous

@danielunderwood I don't know any such site. However, Physics SE is good if you have particular confusions

danielunderwood

I'd like to, but I was a pretty bad undergrad and don't really have the recommendations I need. I have one good one, but I don't know how much that'll do when everywhere wants 3. I also should probably study for the GRE, but that's so boring

enumaris

you can always discuss here :D

Anonymous

Eh, GRE is indeed boring :P

Anonymous

7:53 PM

English grammar n all

Anonymous

And vocab I guess

enumaris

only the subject test really accounts for anything

Anonymous

I don't think many schools ask for the subject tests anymore

enumaris

the general GRE is only used to make sure you know english lol

Anonymous

Or do they?

danielunderwood

7:54 PM

Yeah I'm not too worried about the regular GRE. It may be tough for people who aren't native speakers though

enumaris

could be different now

I applied 7 years ago lol

Anonymous

I'll be trying to ~~avoid~~ circumvent the GRE :P

Anonymous

But still 3 years to go

danielunderwood

Any chance you guys have any advice on how to get recommendations after graduation? I've considered going back as a non-degree student, but that would require getting a job near a school that would let me be in class part of the day

Anonymous

Get in touch with an active research group maybe?

enumaris

7:57 PM

Probably find some topic you're interested in

ask around for who works on that topic

see if you can get a little work done on that topic

danielunderwood

Ahh I didn't know they'd go for that for non-students

I also have to deal with the fact that I want to study a bit of all physics. Like I'm the person that wants to take all the electives. And I know going for grad school likely means something very specific

Anonymous

Heh, you sound like me :P

danielunderwood

There's just so much neat stuff!

enumaris

I mean a MS is pretty general

but a PhD would be quite specific to a research topic

You can be a bit more broad and do a couple topics, but each topic is going to take some significant amount of work

Anonymous

@danielunderwood I'm not very aware of how the US education system works, but often going up and talking to professors in your field of interest helps. A neighboring uni's prof took me into his research group simply because I visited him one day and clearly stated my interests (contacted by mail beforehand). If you're willing to do (almost) free work for them, many would probably take you. Don't spam or annoy them though ;)

danielunderwood

8:05 PM

Do people do MS like grad school in other subjects? Like do some people work while doing it and such or is it covered by a stipend/teaching money like PhD?

Semiclassical

at my uni, at least, the standard practice is that everyone applied for the phd program

Anonymous

Afaik MS degrees are expensive, if not done as a part of a PhD. Depends on the country though

Semiclassical

it's just that some people chose to not complete the phd and just do the masters

Anonymous

And then there are some "MS with research" programmes too

enumaris

There are Teminal degree MS and mid-degree MS

if you apply for a terminal degree MS, you have to find a school that does that

not all schools will have such a program for physics

my school, UCSD, did not have such a program

Anonymous

8:07 PM

Europe offers a lot more terminal MS degrees afaik

Anonymous

PhD's are shorter, like 3-4 years

enumaris

non-terminal degree MS here in the US are not worth much though afaik

Anonymous

@enumaris Oh, you were at UCSD? Nice!

enumaris

was

Anonymous

They have a good machine learning group

enumaris

8:08 PM

Already left heh

Sir Cumference

enumaris

they did some work in autonomous driving I think

danielunderwood

Ahh one of the reasons I'd be interested in a master's would be to show that I have more capability than what my undergrad grades show. I know there are some schools that will accept you on a conditional basis depending on how you do in the master's, but don't know if that's something that I'd have to search out

Semiclassical

@SirCumference June-Brown is a bit of a problem

Anonymous

Haha

enumaris

8:10 PM

a lot of combinations make no sense

also most of those are not questions

just statements

Semiclassical

yeah

Sir Cumference

@Semiclassical Lol true

Cows

@SirCumference hehe nice, nice digging it 😁

Sir Cumference

Ah well the meme fails I guess

Anonymous

e p i c f a i l

Secret

8:12 PM

The following shows nowhere as seen from some interdimensional gap of colors

Anonymous

epicfail.com

Secret

nowhere is one of the "non-place"

with Limbo being the most famous of them

Artworks are often expressive enough to partially capture it physically

while our language struggles

Balarka Sen

Lol Pickford destroyed the knee of that guy

That goalkeeper has a few screw loose

enumaris

might be going to penalties again...

Anonymous

@enumaris Are muricans also watching football?

enumaris

8:18 PM

some

Anonymous

So it's 1-1 now

Anonymous

hmm

Balarka Sen

Maybe not @Enumaris

Croatia goals

enumaris

they did the same thing last time to Russia

England still has 10 minutes to equalize

Balarka Sen

if they do thatd be pretty tight

enumaris

8:29 PM

not much time left

Anonymous

Ah, they just changed the site design an hour ago

Anonymous

The top bar moves down as you scroll

Anonymous

Looks a bit weird

Anonymous

And the search bar is awkward as ever

Semiclassical

lol, a bunch of the grad students are around a laptop watching what's left of Croatia-England

enumaris

8:37 PM

gave 5 minutes of injury time...long time...

Balarka Sen

Croatia vs France now

enumaris

English hearts all over the world break

Balarka Sen

predicting 7-1 loss of France

:airhorn:

Semiclassical

yep, there it goes

Anonymous

JR must be hearing mournings now :P

Anonymous

8:39 PM

@BalarkaSen Entirely possible!

enumaris

Luka Modric is gonna be SOOOO rich...

lol

Danu

England thinking they could win the World Cup was cute :)))

2

Anonymous

burns

Semiclassical

eh. at least the last game was a competitive one. it sucks when you're holding out hope that your team will get to the final, and then they just crush/burn

Danu

@BalarkaSen That was so hype in Russia vs. Croatia

Semiclassical

8:43 PM

(c.f. the minnesota vikings pulling out a miracle win in order to get to the semifinals of the Super Bowl...and then just fell apart against the Eagles)

Danu

when Vida had already taken the yellow card for taking off his shirt in celebration of his goal, and then Russia equalized hahaha

Balarka Sen

@Danu Yeah that was actually pretty good

The Russians were tensed in the shootout, otherwise they'd have won

I really wanted to see a Belgium vs Croatia game though. Sad there's no possibility of that anymore

Sid

Bad luck JR. No homecoming for the World cup

Balarka Sen

@Sid rather, they're coming home

3

;)

Sid

@BalarkaSen Ha! That's brilliant

Balarka Sen

8:49 PM

i rip'd it from math chat

Sid

If anyone is into tennis, so watch the 5th set of Nadal vs Del Potro Wimbledon QF of today.

Some of the most amazing tennis I have seen

Danu

SO GOOD

errrmergerd that was amazeballs

enumaris

ouch, Fed is out

bolbteppa

I think a hard Brexit was just averted

Balarka Sen

@Danu do u know why S2xR2 is not Stein

Danu

8:54 PM

$S^2\times\Bbb R^2$?

Balarka Sen

da

Danu

I'd intuitively think this

Because of the S^2-factor this should only allow one with positive scalar curvature, but on the other hand Myers' theorem says that it should then be compact

That first claim is not so obvious and probably wrong :D

Balarka Sen

Interesting

Danu

I guess $S^2\times \Bbb R_+$ is an open subset of $\Bbb R^3$

and therefore has a zero curvature Einstein metric :P

Transcript for