The h Bar

Anonymous

18:00

@Sid the whole grading system is a scam

John Rennie

@BalarkaSen I have read and enjoyed all the Sandman series and the followup Lucifer. Also V for Vendetta and Watchmen.

Balarka Sen

V for Vendetta is really good. I read the comics after watching the movie (which left me a bit underwhelmed but curious enough to explore nonetheless)

John Rennie

And all of the Hellboy comics.

Balarka Sen

I haven't read those

John Rennie

@BalarkaSen they are highly entertaining, if rather frivolous.

Balarka Sen

18:02

lol

John Rennie

Someone I know might allegedly have copies as CBRs ..

0celo7

@Blue many of the graduate classes at my school are automatic As. As a result

hooy shit what is wrong with my phone today

I mean holy heck of course

Balarka Sen

@JohnRennie clickhole.com/article/…

you might enjoy this

0celo7

As a result they don't like undergrads taking them

Anonymous

@0celo7 Automatic? ORS sheets ?

Anonymous

18:05

@0celo7 At least be happy they allow you to take graduate classes. Here they don't allow us :/ I need to visit the postgraduate department professors after class hours to learn new stuff

Anonymous

It's waaay more shitty here

John Rennie

@BalarkaSen Excellent :-)

Anonymous

However, our profs seem to be lenient with the grading. I don't need to worry much about GPA apparently

0celo7

What they do here is heck you during the year and then apply a massive curve at the end

So you really never know how you're actually doing

@Blue what?

Anonymous

@0celo7 What did you mean by automatic

Anonymous

18:12

Are the test questions not subjective type?

0celo7

You get an A for showing up.

Anonymous

Oh. Strange

John Rennie

This seems wrong to me. Is it just me, or is it wrong?

0

A: Particle definition

This means a set of qualities localized in such a way that they stay together regardless of from which frame of reference you look at them. For example, a static electron has an electric field, but a moving electron also has a magnetic field. While these properties changed because you now looking...

0celo7

Why? Studying for exams might be the greatest waste of time ever. Homework makes sense, but exams are stupid.

Anonymous

@0celo7 I meant A for "just showing up" is a bit too much. Also, homework can be copied. I prefer regular viva and small tests instead of a bulk-type test at the end

Phase

18:16

Is the transformation that takes an orthogonal co-ordinate system to another the Lorentz transform?

Because I'd like to speed some things up if so

0celo7

@Blue no one cares about grades

Classes are for learning, not taking exams

Anonymous

@0celo7 Sure. But one should care about learning stuff well (since they are putting effort into the course). Regular tests ensure that you don't slack

0celo7

In engineering exams make sense

if you can't keep yourself on track without tests you shouldn't be doing a STEM graduate degree

Anonymous

@0celo7 I wish people had that mentality :)

Anonymous

I agree with you

Anonymous

18:19

But the reality is quite different

0celo7

well thankfully I'm somewhere with sense

Phase

18:34

AAAAAAAAAAAAAA

this in infuriating I'm trying to troll people and the pseudo-physicists are out in force

claiming that proper acceleration of g leads to "reaching c in 7 years"

0celo7

@Phase is that wrong?

Phase

Yes

Sid

@Blue you are lucky....

0celo7

@Phase why?

Phase

@0celo7 well why do you think it's right?

0celo7

18:38

v=at

Abcd

@EmilioPisanty Could you tell me what the first response was?

Phase

god damn it ocelot

0celo7

What?

Phase

That's the laziest bait I've ever seen

from someone who understands SR and GR

Semiclassical

Acceleration in SR is one of those things which I never remember how to do right

it's nothing terribly sophisticated

0celo7

18:45

Me neither. I was hoping @Phase wouldn't be a dick and would tell me about it.

Phase

wait

I thought you were being sarcastic

apologies

Semiclassical

I mean, obv. it can't just be a=dv/dt

0celo7

Understanding GR has nothing to do with acceleration. There's probably a gamma in there.

Semiclassical

since then you'd be able to exceed the speed of light if you kept accelerating

Phase

I can barely do it to the standard I get the right answer reliably, I mess up with a lot of the summations etc atm but this is a good link lecture-notes.co.uk/susskind/special-relativity/lecture-6/…

0celo7

18:46

And that messes up the integration.

Semiclassical

something something proper time

i'm not sure constant acceleration even makes sense in SR, though

constant force, yes. but not constant acceleration

0celo7

SR is so counterintuitive.

Semiclassical

Baez has a nice discussion of it: math.ucr.edu/home/baez/physics/Relativity/SR/acceleration.html

0celo7

QM is easy to get a feeling for, despite what Reddit says, but SR is impossible.

Semiclassical

well, in QM there's stuff which is just "nature works this way, get used to it"

but SR seems like there should be more intuition available since it's all geomtric

0celo7

18:50

Nah, QM makes sense to me pretty much. It's all just waves.

@Semiclassical We don't have intuition for Lorentzian spaces.

Semiclassical

exactly

i mean, there's still those three dimensions of space. so some of the Euclidean intuition is still reasonable

but not all of it, and that's where it gets confusing

that's where I'd point to for the source of the confusion

dmckee

@0celo7 Well, yes. But...

Semiclassical

that said, it is rather cute that one gets the result v = c tanh(at/c) (under the condition which Baez specifies in that link)

dmckee

But you are an exceptionally motivated learner and are constantly testing your own mastery. So you don't quit before you know it. Most of your peers are not like that.

But, in addition to being teachers colleges are also certifiers of preparation: governments and employer expect the credential to mean something, and they expect colleges to be able to say 'We know it means something becuase..."

There are schools that don't do grades. You;re not done with a class until your tutor signs off that you have mastered the subject.

I'd love to teach like that, but it is muchos expensive because the teacher:student ration is much lower than in schools with grades.

Semiclassical

How much do you see that model in the US?

Phase

18:59

Question

nevermind

John Rennie

Now this is what I call fundamental research

The sort of research we should put behind us!

Semiclassical

@JohnRennie there butt for the grace of research go I

worse kinda-sorta-not-really-a-pun: I guess you could say they're really interested in the posterior distribution.

Phase

Semiclassical that joke was too good

I can't even think of a {Re_buttal_}

Semiclassical

well, sit on it a while and maybe you'll come up with something

Phase

Now you're really being cheeky

Semiclassical

19:08

yeah, i do feel like i'm just pulling these jokes out of my butt

Phase

God damn it

went to edit it to give it nice font

screwed it up

now edit isnt available

Semiclassical

oh well

Phase

that's just cruel

Semiclassical

re-butt-al

huh, yeah

that's only okay

lol, my rebuttal got flagged

0celo7

@dmckee Thanks but I'm talking about mathematics graduate students, not my peers.

Phase

19:17

wait

you got flagged for that?

Wtf

Anonymous

There should really be a system to flag flags

0celo7

What did I get flagged for now?

If I get banned, goodbye.

Anonymous

I think semic got flagged

Phase

Not you, Semi

What happens if I flag Shog

0celo7

Wtf

Everyone loves @Semiclassical

3

Phase

19:20

do i cease to exist?

Anonymous

@Phase lol...he will kick you "forever" probably :P

Anonymous

(I'm joking)

Phase

What's a joke?!

[flags]

get b& blue

How do you tell when you're flagged anyway

Semiclassical

i'm a 10k user

Balarka Sen

What is flag? Mods don't hurt me, no more

Semiclassical

19:21

so i can see when flags go up....including on my own posts, weirdly

Sid

@Phase you need to be a 10k user.

Anonymous

@Phase You should really pull off that stunt someday XD (Give us your email address beforehand)

Semiclassical

when they go up, i get a little alert that asks me to mark the flag as valid/invalid/not sure

and as a matter of course if my own message gets flagged I mark it as "not sure"

Anonymous

@Semiclassical Can you invalidate flags on your own post?

Anonymous

Then I should get 10k fast

Anonymous

19:23

I'm just lazy to write answers

Semiclassical

I don't know. it seems like I can, but I don't use that option

also, I don't think it's just one person who the flag goes to

I think it goes to all(?) 10k users online, and asks them to judge it as valid/invalid

so presumably it's not just my vote that decides it

Phase

In that case I'd vote invalid then

Since it's just asking all the high rep users if they believe it's inappropiate

if you wrote it, chances are you don't and it's asking for your vote anyway

Semiclassical

true enough. but it feels like it's a bug so I don't use that option

Anonymous

You're too honest

Anonymous

Rather too innocent/good

Sid

19:26

I am only 3k away from 10k....

ANyone willing to give me a bounty? :P

Semiclassical

i'm a strange mix of innocent and cynic

Anonymous

@Sid I can give you...lol

Anonymous

I'd have to take a vacation from SE then. Won't have rep left to chat

dmckee

19:51

@0celo7 Ah. Grad students are a more select bunch.

My grad classes spent less time on tests and often made them take-home.

Emilio Pisanty

@Abcd the link is in my previous comment

Phase

Any tips on how to deal with academic pessimism?

It's getting harder and harder to believe I really have any shot, and idk if anyone else has had the same problem and can recommend any tips, tricks, methods or resources

dmckee

@Sid Because I don't actually know I shall guess: Stanley's were popular around the turn of the 20th century, so I'm going with Stanley.

Anonymous

@Phase Shot at what?

dmckee

@Phase Search term: imposter syndrome.

Phase

19:55

Imposter syndrome doesn't apply though

If I was like you guys then sure, you guys are demonstrably good at Physics and nearly all are postgrad

I'm undergrad

There's still the chance I just haven't been weeded out yet

Anonymous

@Phase What ? Many are undergrads...like me

dmckee

@Phase Sure it does. You're wondering if you are really good enough.

Phase

Yeah but imposter syndrome implies that it's known that I am

Anonymous

I'm just a freshaman. 0celo is an undergrad too

Phase

@0celo7 isn't undergrad he's postgrad in undergrad skin

He's a spooky arcane being

Anonymous

19:57

"postgrad in undergrad skin" XD

Anonymous

I dunno...when I feel pessimistic I just eat a lot of junk food

Anonymous

Everything gets better from then onward

Anonymous

Food is your best friend

Anonymous

Some say music :P

Phase

I don't really enjoy food anymore

Music is good but I like stuff like Radiohead and Elliott smith so it hardly fixes anything. I'd rather find a more solid solution

was just wondering if anyone had any advice

Anonymous

19:59

Okay, but you'd have to state your exact problem first for others to be able to help you :)

0celo7

@Phase if I'm a spooky arcane being what is @BalarkaSen

He's 14

Phase

well

If you're being honest: a Shog9 level entity

if not

Anonymous

@0celo7 He's a 1950's Soviet mathematician

Phase

well shame on you

Anonymous

@0celo7 Well, 17 XD

Anonymous

20:01

An year younger than me

0celo7

@Blue no wonder he boils my blood

@BalarkaSen ::shakes fist::

Balarka Sen

I am become Stalin, destroyer of proletariats

I mean dostroyer of capitalists

Damnit

Phase

Dostoevsky of Capitalists

0celo7

Freudian slip

Balarka Sen

GULAG i say

do not criticize the comrade

0celo7

20:16

@ACuriousMind @JohnRennie is Balarka allowed to threaten putting my in a work camp?

Phase

so no advice? RIP

Anonymous

17 mins ago, by Blue

Okay, but you'd have to state your exact problem first for others to be able to help you :)

Phase

i mean

I just dont want it to come across like I'm compliment / reassurance fishing

I'm just asking for general advice

Anonymous

Don't worry. We won't pat you on the back. :P

Phase

Still, it's pretty sickening to read over what you wrote and realise it comes across like that

What is this letter?

g or phi?

0celo7

20:25

scri

It means null infinity

Phase

Wot

Scri?

What language is that from

Slereah

It's part of the mathscr script in Tex

It's a fancily written I

Anonymous

Letterlike Symbols

Letterlike Symbols is a Unicode block containing 80 characters which are constructed mainly from the glyphs of one or more letters. In addition to this block, Unicode includes full styled mathematical alphabets, although Unicode does not explicitly categorise these characters as being "letterlike". == Symbols == == Chart == == Emoji == The Letterlike Symbols block contains two emoji: U+2122 and U+2139. The block has four standardized variants defined to specify emoji-style (U+FE0F VS16) or text presentation (U+FE0E VS15) for the two emoji, both of which default to a text presentation....

Slereah

$\mathscr{I}$

Phase

jesus

it looks nothing like an I

it looks like a g

Semiclassical

20:30

by comparison

$\mathscr{G}$

Emilio Pisanty

@Phase could be worse

consider $$\LARGE \mathfrak{x}$$

Phase

is that an r?

Slereah

X

Emilio Pisanty

@Phase nope

Anonymous

x

Phase

20:31

...

Emilio Pisanty

@Phase exactly

Semiclassical

$\mathfrak{x}$

...that's messed up

Phase

$\aleph$ why don't we just take more hebrew ones like this

At least they make some sense

Anonymous

That's what mathematicians and physicists do when they have too much time and too less symbols XD

Phase

rather than just "screwed up x"

Slereah

20:32

Please

It's in Fraktur

That used to be a standard script

Emilio Pisanty

^ there it is in action

super clear, no?

Semiclassical

madre dios

Slereah

$\mathfrak{X}$ is commonly used to denote the set of all vector fields

Emilio Pisanty

@Semiclassical yeah

took me six months to realize what the squiggles are

Semiclassical

$\mathfrak{x}$, $\mathfrak{X}$

Emilio Pisanty

20:34

plus, that's one of the standard references for band theory in solids

Semiclassical

Which one is that?

Emilio Pisanty

@Semiclassical Blount, 1962

Semiclassical

hmm, okay

Emilio Pisanty

Formalisms of Band Theory

a bit hard to come by, though

Semiclassical

thing is, at least upper-case X in Fraktur makes sense

the fraktur page on Wikipedia is inconsistent on lower-case x: en.wikipedia.org/wiki/Fraktur

in most places it looks like a lower-case version of $\mathfrak{X}$, but in the German typescript examples it's indeed $\mathfrak{x}$

Emilio Pisanty

20:41

hmmmm

$$\Huge ⅏$$

ooooh, it worked

$$\Huge ⅏⅏⅏⅏⅏⅏$$

that's unicode for "telephone cable", also known as "if you're feeling down, call the samaritans"

Semiclassical

evidently Fraktur typscript had an ideological component in Germany up until WWII: en.wikipedia.org/wiki/Antiqua%E2%80%93Fraktur_dispute

Emilio Pisanty

OK, almost. There's all sorts of weird shit in unicode.

Semiclassical

it's interesting that I know about Fraktur but not Antigua, or at least not under that name

Antigua won out so completely that we don't even remember that it used to be a point of controversy

Slereah

The one in common use here is of course the telephone operator

$$Γ = ☎^{-1}ΨΨ^-$$

Semiclassical

$\fbox{ } ⅏\fbox{ }$

hrm

i wanted to make a spring

$\msquare$

$\fbox{$\phantom{5}$}\big{⅏}\fbox{$\phantom{5}$}$

lateeex

Anonymous

20:56

Looks like it's break Latex time ;)

Anonymous

@BernardoMeurer should have been around

Emilio Pisanty

@Blue $$\Large 🎉🎊💃🏽🕺🏻$$

Balarka Sen

$$\blacksquare ⅏ \blacksquare$$

huh

was totally sure $\blacksquare$ was a thing

hey it is

what in the name

it doesn't enlarge specific things

$\large{\blacksquare} \huge{⅏⅏⅏} \large{\blacksquare}$ Hooke's law ftw

5

that's a fine spring

0celo7

I need to use $\mathfrak x$ in a talk

Emilio Pisanty

@0celo7 if you do, then the gods of notation will murder you in your sleep

> * Units are needed unless quantities plotted are dimensionless. The ideal format for units in figures is to set them in parentheses, following the quantity being plotted. Alternatively the units can be included in the figure caption.

goddammit, Phys Rev A

didn't you see that we pulled the Get Out of Units Jail Free card?

Balarka Sen

21:11

units are the worst

Emilio Pisanty

> we use atomic units unless otherwise stated

boom, units sorted

Semiclassical

lol

I don't even remember what all the various atomic units are

i tend to just remember eV and such

Slereah

There's a.m.u

Semiclassical

~ 1 GeV/c^2

Balarka Sen

wai

Oh I see, E/c^2

0celo7

21:14

E=mc^2

Balarka Sen

that's a unit for mass then

Semiclassical

ya

Balarka Sen

@0celo7 sniped right at ur face

Semiclassical

or just 1 GeV if you say "screw you speed of light"

Balarka Sen

I have seen physics bruv

Semiclassical

21:15

more precisely, it's 0.931 GeV/c^2

0celo7

@BalarkaSen that was a response to you

Slereah

Screw you speed of light

you know

One thing I wonder is

In classical physics with EM

What happens to a bounded atom approaching the speed of light, or going over it

Balarka Sen

@Semiclassical because E = mc^2 is just an approximation, and it's really E = mc^2/square root of somefing?

Semiclassical

radiation

Slereah

Since the system isn't Lorentz invariant, the EM field can't simply be assumed to work the same as in the rest frame

Is the atom still bounded?

Since there's gonna be a "lag" between the atom and its EM field

Semiclassical

21:16

@BalarkaSen nah. it's an empirical result

Slereah

which is only propagating in the ether frame

0celo7

E=mc^2 is empirical?

Semiclassical

no, but 1 amu = 0.931 GeV/c^2 is

Slereah

In the Lorentz ether theory, you had $E = 4/3 mc^2$

Semiclassical

there's no physical reason (outside of full QCD, I mean) why 1 amu ~ 1 GeV/c^2, that's just what it happens to be

Slereah

21:17

This was due to the self energy of charges, assuming electromagnetic mass

0celo7

I have no idea what that even means @Semiclassical

What do you mean it's empirical

Both sides are a mass

What theoretical basis could there be

Semiclassical

??

I feel like we're talking past each other

@BalarkaSen I was responding to this

Sir Cumference

@Slereah Amen

Semiclassical

and explaining that the fact that 1 amu ~ 1 GeV/c^2 isn't some approximation of E=mc^2/\gamma

Balarka Sen

How is amu defined

Semiclassical

21:22

I'm actually forgetting now

Sir Cumference

I do have to wonder, how much easier would a math major be if Newton never came along

Semiclassical

"It is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest,[2] and has a value of 1.660539040(20)×10−27 kg, or approximately 1.66 yoctograms. "

Slereah

Atomic mass unit is like

Balarka Sen

ack

Slereah

It's based on carbon mass, I think?

One carbon atom is 12 amu or something

Balarka Sen

21:23

one day there will be a unit called omg

and 1 omg will be something terrible

Semiclassical

@Slereah three lines up man

Slereah

Well there is the Oh-my-god particle

Oh-My-God particle

The Oh-My-God particle was an ultra-high-energy cosmic ray detected on the evening of 15 October 1991 over Dugway Proving Ground, Utah, by the University of Utah's Fly's Eye Cosmic Ray Detector. Its observation was a shock to astrophysicists (hence the name), who estimated its energy to be approximately 3×1020 eV or 3×108 TeV. This is 20,000,000 times more energetic than the highest energy measured in electromagnetic radiation emitted by an extragalactic object and 1020 (100 quintillion) times the photon energy of visible light. Therefore, the particle was an atomic nucleus with a kinetic energy...

Semiclassical

anyways

Balarka Sen

@Slereah This is beautiful

Semiclassical

Carbon-12 is more-or-less 6 protons+6 neutrons

so 1 amu should approximately be the average of the proton and neutron masses

Slereah

21:26

up to some binding energy

Balarka Sen

OH MY GAH!

►

Slereah

HARRO EBURRINYANYAN

Semiclassical

proton is 0.938 GeV/c^2, neutron is 0.940 GeV/c^2, and 1 amu is ... 0.931 GeV/c^2.

i guess that binding energy is big enough to make a difference

okay, yeah, the binding energy of Carbon-12 is 0.092 GeV

so that's definitely enough to make a difference in the definition of the amu

0celo7

@BalarkaSen mass of carbon 12 div by 12

Semiclassical

that said, the main reason why the amu is nearly 1 GeV/c^2 is because protons and neutrons both have masses which are almost 1 GeV/c^2

but absent hard calculations in QCD there's no way you'd get that result. in particular, there's no deep relation between 1 GeV/c^2 and 1 amu.

and most of the protons mass is the binding energy from the strong force, sooo yeah

Student404Mus

21:43

hello

what is the use of unitary transformation in physics

0celo7

fucking github deleted everything again

I can't keep doing this

Student404Mus

hey there please respect us

Anonymous

@Student404Mus Did you search anything yourself?

Anonymous

I see 100s of pages on that topic

hwlau

22:02

@BalarkaSen haha. These pronunciation make it less serious.

0celo7

22:18

@BalarkaSen

looool that thumbnail

here youtube.com/watch?v=eytCougL1m0

Balarka Sen

lmao what did i just watch

0celo7

@BalarkaSen the seat is a heck machine

Phase

what?

0celo7

Curb Your Enthusiasm - Leon figures out the secret of Larry's car - Season 8 Ep. 9

►

Phase

22:33

oh.

Balarka Sen

lmaaoo

what the frick is this TV show man

0celo7

@BalarkaSen literally the greatest show ever

@BalarkaSen Sir, what is $\int f(r) d^nx$ in terms of the radial integral?

what's the overall factor

$\omega_{n-1}$?

Phase

How much

that's what happens when you hit Enter instead of backspace.

I was gonna ask: how much should a new first year know to be a good student

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