The h Bar

ACuriousMind

20:00

but for the (projective) Hilbert space, the embedding of $H_1\times H_2\to H_1\otimes H_2$ or of $P(H_1)\times P(H_2) \to P(H_1\otimes H_2)$ (the Segre embedding) is not surjective. The states not in the image of these embeddings are the entangled ones

Slereah

I see

naturallyInconsistent

@SillyGoose That is just like students who have only heard of Newtonian mechanics in terms of forces and not understanding what is the point of doing Lagrangian mechanics or Hamiltonian mechanics. Then they get supremely shocked when I tell them that forces are the first to die in the quantum revolution.

And then you still have new things being found in Hamiltonian mechanics in symplectic manifolds language every so often.

Silly Goose

i wish to learn symplectic geometry :P

user 85795

Losing Newton's mechanical universe is a shock to HS students.

Slereah

Shouldn't be too hard

There's a reason they call it simple-tic

Silly Goose

20:05

Lol

Slereah

Just kidding it's actually greek for complex

Silly Goose

Let $M$ be a graded $R$-module where $R$ is a graded ring. So $M$ decomposes into a direct sum $\oplus_n M_n$ such that $R_iM_j \subseteq M_{i+j}$. What is the intuition for introducing such a structure?

ACuriousMind

@SillyGoose polynomials with the grading being the highest non-zero power

Slereah

Also forms

Sir Crackpot

@bolbteppa how dare you thinking that

It's my punishment

Feb 15 at 17:23, by Sir Crackpot

I can now say dumb things without covering my master in mud

bolbteppa

20:13

I'm just saying 'Sir Crackpot' beside a picture of Feynman could be a crank calling Feynman a crank, but who am I to judge I'm sure people on the main site wont make that mistake :p

Everybody understood my hardcore Vito Volterra reference after all

Vito Volterra

Vito Volterra (, Italian: [ˈviːto volˈtɛrra]; 3 May 1860 – 11 October 1940) was an Italian mathematician and physicist, known for his contributions to mathematical biology and integral equations, being one of the founders of functional analysis. == Biography == Born in Ancona, then part of the Papal States, into a very poor Jewish family: his father was Abramo Volterra and his mother, Angelica Almagià. Abramo Volterra died in 1862 when Vito was two years old. The family moved to Turin, and then to Florence, where he studied at the Dante Alighieri Technical School and the Galileo Galilei Technical...

Sir Crackpot

*think

@bolbteppa I don't want to change my old propic as I made it editing a book cover :P

Sir Cumference

well you could just replace it with a picture of crack and pot like ACM mentioned

bolbteppa

The picture is cool

Sir Crackpot

I'm covering Feynman in mud again

I'm a disgrace to that guy

@bolbteppa Should I read your name like "Volterra", then?

user 85795

He was from a different era.

Sir Cumference

20:17

@SirCrackpot why not just go with this

bolbteppa

You mean you already weren't? It's Volterra using ****ardized Russian letters in the English alphabet

Sir Cumference

a crack pot

Sir Crackpot

Oof so be it

bolbteppa

It's a ****ing stupid name I regret

user 85795

Sir mix a lot

Loong

20:19

@SirCumference Ask John Baez

Sir Cumference

@Loong never knew this was a thing lol

Crackpot index

The Crackpot Index is a number that rates scientific claims or the individuals that make them, in conjunction with a method for computing that number. It was proposed by John C. Baez in 1992, and updated in 1998. While the index was created for its humorous value, the general concepts can be applied in other fields like risk management. == Baez's crackpot index == The method was initially proposed semi-seriously by mathematical physicist John C. Baez in 1992, and then revised in 1998. The index used responses to a list of 37 questions, each positive response contributing a point value ranging from...

Sir Crackpot

ACM, it's time to push your magic button

Well done :P

Sir Cumference

lol nice

ACuriousMind

alakazam!

user 85795

:O

ACuriousMind

20:21

I have transformed you into a pot

user 85795

Literally 😂

Sir Crackpot

@bolbteppa I knew its meaning but I got used to reading it like an English person would pronounce it for the version with English letters

In contrast to the one in your profile bio

Loong

@ACuriousMind Curiously enough, the only thing that went through the mind of the bowl of petunias as it fell was Oh no, not again.

Sir Crackpot

@ACuriousMind Well, at least you didn't transform me into pot

bolbteppa

As did I, hence the stupidity of the name :(

Sir Cumference

20:24

@bolbteppa well you're preaching to the choir there

Sir Crackpot

I'll get used to calling you Volterra

bolbteppa

The thing in my picture is a string field derivative from Kaku's String Field Theory paper

user 85795

@SirCrackpot you're an editor?

Sir Cumference

I found out a while ago that all my emails were being sent under the name "Sir Cumference"

Silly Goose

@SirCrackpot now people might not recognize you ;)

Sir Cumference

20:25

never realized I was asking for research under that name

Sir Crackpot

@user85795 No no, I did only small edits, like moving the cat and the diagram but I'm too lazy to do it again if the picture is lost

Sir Cumference

stupid google linking youtube names with gmail accounts

bolbteppa

@SirCrackpot are you planning on going on to the next stage

Sir Crackpot

That was my picture forever (as Mr. Feynman)

@bolbteppa Earth is flat

(Locally)

bolbteppa

@SirCumference There is no alternative interpretation to your name, especially with the spacing, don't worry about it

Sir Crackpot

20:27

@SillyGoose don't you people forget me :P

Sir Cumference

so it's pretty easy to roast me

Sir Crackpot

@bolbteppa why don't you just switch to Вольтерра

@SirCumference good job, from now on I won't be able to read it properly anymore

Sir Cumference

probably a mistake to mention that here...

bolbteppa

No one will type those letters

Sir Cumference

before that becomes my "nickname" elsewhere lol

user 85795

20:29

Discord is savage

Sir Cumference

@user85795 well only when you have immature friends with mod powers :P

user 85795

I see.

Silly Goose

what do you guys think the benefits of an algebraic vs geometric formulation of a thing are

ACuriousMind

algebra is cooler

Silly Goose

Lol

i saw an answer here on stack exchange that said thinking geometrically lead wigner to his classification of one-particle states...but um isn't representation theory entirely algebraic. i didn't quite understand the history behind that

ACuriousMind

20:33

ask a silly question, get a silly answer :P

user 85795

Geometry uses less words.

Silly Goose

well maybe i can be more specific. what is an example of the geometric formulation of quantum mechanics (for finite dimensional systems) giving a result that is hard to see in an algebraic formulation of it

bolbteppa

Wigner is great but people were doing QFT for around 20 years before he did that, there is a whole other scheme people ignore

Silly Goose

@bolbteppa what is the other scheme?

ACuriousMind

@bolbteppa who exactly was doing QFT in 1917?

bolbteppa

20:38

Sorry he was 1939 right, I should have said 10 years

ACuriousMind

also Wigner explicitly acknowledges that Majorana and Dirac found most of the representations non-rigorously in earlier work

Sir Crackpot

@ACuriousMind well, technically QM is a 0+1D QFT :P

ACuriousMind

@SirCrackpot still really only gets going in the '20s

bolbteppa

As this summarizes, Pauli and Fierz basically took what people had been doing the past decade (energy positivity thing) and generalized it to all spins, but Wigner came out with a variation on this that is very group-theoretic

Sir Crackpot

@ACuriousMind oh right, I was thinking of old QM

Which is CM with cheats on

ACuriousMind

20:41

de Broglie is '24, Heisenberg's and Schrödinger's mechanics shortly after that, I don't think you can call anything prior to this "QM" in other than a historical sense

user 85795

It help put the roar in the 20s

The bomb put the dirty in the 30s

bolbteppa

Before 1926 it was all a big mess as far as I can tell

ACuriousMind

@user85795 what bomb?

bolbteppa

(Almost) everyone is apparently getting their decades wrong :p

user 85795

The work on the foundations of it.

ACuriousMind

20:43

people only really realized that fission existed at the very end of the '30s

c'mon people, this is trivial to look up

user 85795

Well, there was a depression...

ACuriousMind

@SillyGoose there's a bunch of stuff using the Fubini-Study metric which is much more natural in projective Hilbert space geometry

Obliv

I can't tell if my ability to communicate ideas irl is getting worse by texting/chatting online or not but it feels like it's not where I want it to be compared to my ability to write/type

Like I'll have a bunch of good questions/interesting ideas throughout lecture but then when I discuss them with my prof it just comes out like jumbled rubbish

i bet stephen hawking didn't have to deal with this problem

Sir Cumference

first time I've seen someone be envious of his condition :P

Obliv

maybe it's because it's real time and I'm used to formulating my sentences in my head a bunch of times first idk that sounds like an excuse

bolbteppa

20:53

Hawking came out with a good bit of nonsense, I would embrace the humanity of it all

ACuriousMind

@Obliv you can formulate sentences in your head before speaking them out loud, too ;)

Sir Cumference

I mean speaking on the spot is a different thing from speaking over chat

where you can read over things before posting

and the difference is probably more pronounced with physics since it requires a lot of thought

bolbteppa

Talking about a technical subject in person is always vague and handwaving and loose unless you are sitting down writing things clearly, it's completely normal

Obliv

@ACuriousMind ugh okay but it feels like there's so much pressure when talking to a professor, like i don't want to take up their time but I also don't want to just back down lol

ACuriousMind

it's usually perfectly fine to take a few seconds and just go "Hmmm" or "I'm thinking" if you feel you're talking too fast

Sir Cumference

20:55

@Obliv you could always shoot them an email

and they can respond if/when they have the time

ACuriousMind

or if you actually have these questions/thoughts during the lecture, write them (or at least notes) down and read them off?

Obliv

@bolbteppa Ok, I'm glad I'm not the only one then. @Sircumference that sounds like a much better idea lol.

@ACuriousmind true, but what if they respond and I have to think on the spot again shudders

ACuriousMind

that's life :P

Silly Goose

writing down your question in a precise manner is usually nice. it sometimes results in resolving the question u were asking in the first place

Sir Cumference

@Obliv well at some level you'll have to get used to that :P

research meetings, answering questions during a presentation, etc.

ACuriousMind

20:57

you can always just go "I'll think about that" and formulate a response for next time (or an email)

Silly Goose

@Obliv u can always tell them that u have to think about it and ask later :P

Obliv

like okay, we were going over electrostatics again and the whole "E-field in a conductor is 0" thing came up and I wanted to be cool and point out the situation where charge can exist on the points of symmetry but I couldn't formulate it at all well and I just floundered like a fool

user 85795

> In 1938, three chemists working in a laboratory in Berlin made a discovery that would alter the course of history: they split the uranium atom

ACuriousMind

I regularly say "I'll have to think about that and get back to you" when someone asks me a question I can't (or don't want to) answer on the spot

user 85795

16 mins ago, by user 85795

The bomb put the dirty in the 30s

nickbros123

21:03

@ACuriousMind a more chaotic evil kind of reply would be "it's rather easy, I'll let you think about it"

user 85795

They must've been working on it throughout the depression years @Loong

Obliv

idk how other people's brains work but it seems like when I listen to a lecture my attention splits into a bunch of ways randomly and I have to restrain myself to follow the lecture silently.

Sir Cumference

I mean I just don't learn in lectures

I read the textbooks

nickbros123

@Obliv I don't follow lectures, I sleep there.

user 85795

LoL

Obliv

21:05

why is that so common lol, I don't understand why people don't take lectures seriously

Sir Cumference

just not how I learn

maybe it's because of my ADHD but following a long verbal conversation is difficult, especially since I can miss details

and I'm constantly scrambling to get it into a notebook

much easier to just read carefully structured text and be able to look back on it

ACuriousMind

@nickbros123 well, this was more meant in a work context where someone asks me about some obscure behavior of our application that I have to figure out myself first :P

Obliv

@SirCumference but a textbook can't answer your questions

Sir Cumference

usually in that case i start googling

or ask here if i'm completely at a dead end

nickbros123

@Obliv I follow lectures when it's interesting. By follow i simply see what the lecturers tryna do and maybe the first 3 steps and I'll go back to sleep

Sir Cumference

21:07

@nickbros123 don't they get mad if they see you sleeping tho?

I usually just nod and pretend to be following

Obliv

not where I live, it's crazy I see students with their heads on their desks in a lecture for optics or something

user 85795

They're used to it :P

Sir Cumference

well you're lucky :P

Obliv

I'm like, why even bother showing up lol are they absorbing the lecture subconsciously or something? Maybe they'll perk up at the sound of "this will be on the exam" lol

Sir Cumference

my undergrad and graduate programs have a lot of classes with stupid mandatory attendance

which is worse than useless since I come out with a fragmented understanding of the topic

nickbros123

21:09

@SirCumference the profs know me rather well. They don't mind it. I usually ask my questions in office hrs

Sir Cumference

much rather just teach myself than waste 1.5 hours in an unhelpful lecture

sometimes I'll pretend to take notes on my computer and instead be chatting here

user 85795

Autodidacts are rare.

Sir Cumference

i mean it's just the only way I can learn

i find it's fairly common among others with ADHD

nickbros123

When I'm not sleeping in a lecture i just do my own thing, some problem in a book etc. I pay attention when I hear something interesting tho

Sir Cumference

i need time to process information at my own pace

nickbros123

21:12

@SirCumference another reason to believe I have ADHD

Sir Cumference

@nickbros123 well, you could always get a clinical test

medication is pretty helpful for treating it

though they generally won't do anything if you don't have it

Sir Crackpot

@Obliv because you only deserve my attention if you put effort in what you do

Sir Cumference

Tbh I've had a lot of profs who are really passionate about teaching, but it just doesn't work for me

Sir Crackpot

If I see you teaching unwillingly you don't even deserve that I listen to you

Sir Cumference

I've got a worse memory than a goldfish, so I need to spend time going over things to fully take them in

Obliv

21:16

Are you and Mr. Feynman going through a break? @SirCrackpot

@SirCumference I'm like that for physics but for some reason I remember things in math a lot better

Sir Crackpot

Until I'm someone worthy of carrying that name

user 85795

Some profs want their students to make study guides out of their lectures.

nickbros123

@SirCumference I'm too lazy for that. What I find my self doing (more recently though) is that I have 10-11 tabs open, spanning about 3-4 different topics (now, thermodynamics-callen, probability-feller, statistics-hogg, rudin-PMA, Hoffman kunze-LA) and I just jump around every 20-30 mins

Sir Cumference

@user85795 I honestly just hate when profs think they know the objectively correct method of learning

Obliv

@SirCrackpot plays sad violin

Sir Cumference

21:17

like people have their own strategies

user 85795

@SirCumference yeah, it happens a lot.

Sir Crackpot

@Obliv kind of

Sir Cumference

mandatory attendance is the dumbest thing, everyone in the class is an adult who knows how to learn by this point

Obliv

@SirCumference plays angry violin

Sir Crackpot

I will always deny Feynman's "there's no miracle people"

Sir Cumference

21:18

@Obliv well it is a very frustrating thing lol

where like 10% of the grade is showing up to class and asking questions

just let me learn and test me on the material

nickbros123

@SirCrackpot I kinda agree with Feynman on this one. Or at the very least, think it's useless to think the opposite

Obliv

@SirCumference I'd be grateful that 10% of the grade is just showing up lol. I don't have that luxury, but some classes do require it (but it doesn't add to the grade, it just subtracts from it if you don't show up)

user 85795

wtf

Sir Cumference

@Obliv I mean it's really dumb either way

the grade should reflect my understanding of the topic, nothing else

lectures just take time away from my studying and confuse me by introducing things too quickly

nickbros123

@ACuriousMind wouldn't it be funny if you said that in this context aswell :D

Sir Cumference

21:21

i.e. it just makes it much harder for me to learn

i gotta make an active effort to tune them out so i don't get my understanding of the material thrown out of wack

Arjun

@SirCumference I thought it was just like that in indian colleges where I come from lol

Obliv

@SirCumference I see, you got your own head canon that you gotta maintain. I feel that way too

Sir Cumference

i dunno if "head canon" is the correct terminology lol

user 85795

they want speed and at their pace

Sir Cumference

@user85795 basically this

nickbros123

21:23

@Arjun bruh go to sleep xD

Arjun

We have this stupid 80% attendance criterion ..u might be einstein of some subject but if u dont have enough attendance they won't let u take the exam and u will have to repeat it

Sir Cumference

@Arjun fuck that

seriously things like that piss me off

Obliv

if ur einstein of some subject, then don't worry about it and just go be a swiss patent clerk

and formulate your theories in your spare time :)

user 85795

LoL

Einstein never used flash cards :P

nickbros123

@Arjun it was just that 1 semester bruh, we got scammed

Arjun

21:26

It actually happened to me once in electrodynamics course me and @nickbros123 have literally topped the mid term exams by huge margin..but we skipped all classes cut we were learning better by studying zangwill and griffiths on our own..but because we didn't have attendance they didn't allow us to sit for the exams

Sir Cumference

@nickbros123 are you guys in the same uni or something?

Arjun

We literally had to beg the prof to let us write the exams ..finally we got the permission though

Sir Cumference

@Arjun that's the stupidest shit I've ever seen :/

nickbros123

Peak times that

ACuriousMind

...but presumably this wasn't a secret surprise rule, right? :P

Sir Cumference

21:27

@ACuriousMind well in that case the prof is just an asshole, not a surprise asshole :P

ACuriousMind

like, if they're even taking attendance, you know there's going to be some problem if you have literally none :P

user 85795

No, it was a rule to see who would obey it.

nickbros123

@ACuriousMind well, it was never enforced ever before, but it existed. And we were the batch to get the axe. It was kinda stupid of us tbh

Obliv

@SirCumference for someone who was so adamantly defending physicists earlier when someone called them arrogant, you seem to have no restraint in disparaging a professor :) I'm just teasing

Arjun

@ACuriousMind we didn't have it in sem 1 of our uni..they suddenly introduced it in sem 2 ..we thought it wouldn't matter but got screwed

Obliv

21:28

I understand your passion

Sir Cumference

@Obliv well requiring mandatory attendance is a very different thing from doing scientific research :P

ACuriousMind

@SirCumference it might not be up to the prof (at my university something like this would have to have been decided at the faculty level)

Sir Cumference

@ACuriousMind well someone responsible for this is the asshole I guess

nickbros123

@ACuriousMind this stuff was decided for us by the academic administration office. It was a clear rule tbh, but never enforced till our time came

Sir Cumference

it's just a nonsensical thing to penalize people for

Arjun

21:30

Yupp we were the scapegoats

ACuriousMind

To be clear, I'm not defending the rule - I think mandatory attendance is silly, and I've never had a single course that had it

Arjun

Now we make sure we get the attendance by hook or crook lol ifykyk

nickbros123

@Arjun what do u mean bruh we literally go to all the lectures xD

ACuriousMind

I much prefer our system where exam admission was usually decided by having at least 50% of the total points in the weekly exercises

nickbros123

To sleep there tho that's a different thing

user 85795

21:32

This reminds me of the whole face mask rule ::runs::

Obliv

I had such a naive view of what college & higher education would look like back in my youth. I thought that there'd be a perfectly curated path for us and it would be modified based on our abilities/who we were with selective attention. Nah, it ain't like the fictional stories :(

Sir Cumference

@ACuriousMind sounds like german universities are a lot more sane than US ones

Sir Crackpot

@ACuriousMind I prefer Italian system where you can take the exam whenever you want

Sir Cumference

I've had classes with mandatory attendance + separate mandatory problem solving sessions

like wtf

just let me learn like a normal human being

Sir Crackpot

Although most courses require attendance, they just don't care

Obliv

21:33

it's crazy that you guys even have exam admission requirements. As long as you got $$$ you can fail the class and take the exam, but you won't get a passing mark obviously

Sir Crackpot

More seriously, it sucks to have no problem sets

Obliv

@SirCumference recitation?

ACuriousMind

@SirCumference there existed courses (mostly in the humanities) where attendance was taken - but usually you then passed these simply by having attendance (passes from those are called Sitzscheine, lit. "sitting certificates", because you passed the course just by sitting in it)

Sir Cumference

@Obliv yeah

where you waste 1.5 hours on solving problems you don't want at the moment

like it forces me to scramble to learn the material when I'm trying to go at my own pace

if I'm just given exams and homeworks, I'll be perfectly fine

nickbros123

Correct take @SirCumference

Arjun

21:35

@SirCumference We also have these stupid tutorial sessions where the TAs come and solve a bunch of plug n chug problems and problems which might possibly repeat in the exam

Obliv

Lol my algebra recitation is just a smack in my pride every time I attend. It's so sad our class was doing so poorly in them that the graded part of recitation has become solving an extremely basic question. The one we had today was like "if you have $f(x) \in F[x]$ for a field $F$, where $f(x)$ has degree 5 but no roots and no quadratic factors, is $f$ reducible why or why not" @SirCumference

Arjun

As if that is not enough if u have enough attendance in these tutorials you might get 10% bonus score in the exams

ACuriousMind

@Obliv I wasn't paying my uni any €€€ or $$$ :P

user 85795

They are stuck building up from the JEE format of education.

Obliv

@ACuriousMind yup, which is why I think the faculty is more motivated to get you guys to learn? Here it's more like reputation based but there it's govt. funded

Sir Cumference

21:37

@ACuriousMind I'm starting to think I should've been born in germany...

Obliv

idk how that matters actually nvm

Sir Cumference

maybe it's an american university thing but they're insanely expensive

nickbros123

@user85795 JEE format actually made sense though. They don't care if you attend lectures or not. If you have the scores, you good

Arjun

@ACuriousMind you got some sort of scholarship or is it a norm at German universities?

Sir Crackpot

@ACuriousMind would I get banned if I said you taught quantum finance in exchange? :P

ACuriousMind

21:38

@SirCrackpot we had that in the smaller courses later on; the "mandatory problems sets" are partly there to sieve out people from the large intro classes who aren't putting in any effort

Obliv

sheaves?

ACuriousMind

@Arjun all public education is tax-funded and (almost) entirely free for the individual

user 85795

@nickbros123 but they want you to be testable at their pace

Sir Crackpot

@ACuriousMind Regardless of that, I don't have any and while studying for exams I don't find time to do problems on my books very often

Sir Cumference

@ACuriousMind in other words your tax money is actually properly spent

Sir Crackpot

21:39

Yet, most book authors suggest to do almost all of them

ACuriousMind

I did have a scholarship, but that just meant I didn't have to get (interest-free, governmental) loans to get money for living

Arjun

@ACuriousMind then how do they gauge whom to let in? Like do you have some entrance exams after high school?

Obliv

I like how you have to boast interest free governmental loans but I guess ours is interest free if they're subsidized so nvm

ACuriousMind

@Arjun depends on the uni and the field; e.g. medicine and law are highly competitive with essentially only the people with the best high school grades having a chance (+ specific admission tests), but e.g. my physics bachelor's degree let anyone in with straight As in math and physics

Sir Crackpot

They gauged that and in response ACM gauged field theories

Arjun

21:42

Lol

nickbros123

@SirCrackpot the ACM gauge fixing

Sir Crackpot

For real, I'm triggered by the fact you ask how they gauge and ACM replies saying it depends on the field lmao

ACuriousMind

(perhaps relevant background information here is that we have different kinds of "high schools", where only the gymnasium - which is 13 or 12 years as opposed to the 10 years in the other forms - directly allows you to go to uni)

Sir Crackpot

That cracked me up actually

(Been meaning to say that since I became a pot)

5

Obliv

Oh my god..

idk if I want to star that or close the chat

user 85795

21:44

star it

nickbros123

@Arjun go to sleep bruv we got lab today 💀

Arjun

I'll sleep in the lab lol

ACuriousMind

@SirCumference there's lots of things wrong with the specifics but yes, the basic idea is sound

user 85795

RIP 😭

nickbros123

I don't think I'll make it to the lab

Sir Crackpot

21:46

Ooooh are you colleagues?

Sir Cumference

@ACuriousMind well I've heard german healthcare is a hundred times better than the US too lol

in fact the same applies with most countries

healthcare and higher education in the US are absurdly expensive

ACuriousMind

@SirCumference same thing - lots of things wrong with the specifics, but... :P

Obliv

yeah but do they have the world's largest military budget? @SirCumference

Arjun

@SirCrackpot yupp..we both study in the same college

Obliv

I feel like that's something 0celo7 would say

3

Sir Crackpot

21:47

@Arjun cool to have some colleague on SE

Sir Cumference

@Obliv he probably would lol

Sir Crackpot

Oh, maybe fellow students sounds better

In Italian we use the same word for colleagues and fellow students in uni

Sir Cumference

tuition for US universities can cost upwards of $250,000 for a 4-year education (not counting the impact of scholarships, etc.)

ACuriousMind

@SirCrackpot in German we say Kommilitonen, whose literal meaning you can probably guess from Italian

Sir Crackpot

@ACuriousMind I'm impressed that you know I can guess from Italian

Oh, Latin

nickbros123

21:49

@ACuriousMind in Goldstein they say Kamiltonian

2

ACuriousMind

lol

Obliv

@nickbros123 really?

Sir Crackpot

I mean, Physics is kind of war

Arjun

@SirCumference I would rather invest that in some stocks and generate a life long revenue lol..just spend my life studying physics and math without worrying about money

Sir Crackpot

@nickbros123 It's pretty common

Qmechanic says that too iirc

ACuriousMind

21:51

guys, the joke is that it's a hilarious non-sequitur to my "in German we say Kommilitonen", stop taking that seriously :P

Sir Crackpot

I didn't even read to whom he was replying tbh

I had an opportunity to mention Qmechanic, so I can move onto the next topic

-184 points and Qmechanic reaches 200k

Obliv

Is it possible to be good at physics without being good at math?

Arjun

@ACuriousMind I'm sorry if it's a bit personal but why did you not get into academia and chose to get into software ? Cuz I'm hella confused if I would wanna go down the acad path..I just wanna decent paying job with enough time to study physics lol

naturallyInconsistent

@Obliv Michael Faraday existed.

Obliv

Wasn't there some colleague of a physicist who was able to relate some concepts in EM but couldn't formulate it mathematically but he still got some credit for the ideas

maybe it was faraday then idk

ACuriousMind

21:56

Jul 14, 2023 at 18:55, by ACuriousMind

@nickbros123 I realized I didn't actually enjoy doing research in theoretical physics all that much, I didn't want to move around the world chasing academic positions because I like where I am right now and I wasn't all that in love with string theory and QFT anymore after actually having studied them for a while (but I could've changed fields, sure).

user 85795

Do you still self study string theory :^)

Sir Crackpot

Damn, if you are that good without being that in love with it... You'd be Witten's Witten if you still loved it lol

Arjun

@naturallyInconsistent but do you think it is possible in this day and age considering how much physics has advanced and playing around with coils and magnets wouldnt produce any publishing worth knowledge? (No offence to Faraday lmao..I'm in no way am undermining his work)

Sir Crackpot

@Arjun One could ask this question the other way around: why aren't you in an alternate universe?

user 85795

@SirCrackpot Witten has a lot of stuff on YouTube

Obliv

22:04

@Arjun what knowledge is worth publishing is entirely subjective and the state of academia today (from what I gather peripherally) is wrought with pointless publications or straight dishonesty lol

Arjun

@SirCrackpot Even there I think they'd have to learn some sort of logical framework to study the physics of that universe lol

Obliv

so I don't know if it matters whether something is worth publishing anymore.

Sir Crackpot

@Arjun check ACM's bio

@user85795 I know that

> In an alternate universe, I'm a theoretician interested in (algebraic and differential) geometric aspects of physics, gauge theories, non-perturbative quantum field theory, string theory/M-theory, and the application of representation theory to physics.

Arjun

@SirCrackpot maybe he already is in one who knows

Obliv

he definitely proved it in the alternative universe

naturallyInconsistent

22:08

@Arjun I do not believe it, but physics training makes meow not really care about my beliefs. It had happened before, it can still happen, even if the chances are really small.

I mean, think about the guy who made blue LED. It doesn't seem like his work was into a lot of maths, but rather diligently chasing down a possibility that other people had written off as improbable.

user 85795

meeeooow

Arjun

@Obliv When I said publishing worthy I meant knowledge that has not already been discovered..and to do that I think one should understand all the physics previously discovered ..and to do that you should study a lot of math

I could be wrong lol

naturallyInconsistent

meowwww

nickbros123

@Arjun ok so we've made up our minds to skip lab today. Got it

Arjun

Bro u been saying sleep to me when u yourself were on chat lol

naturallyInconsistent

22:12

@Arjun oh, one definitely does not need to know all the physics discovered prior. Of course, one should not be totally ignorant, but exhaustive knowledge can easily become a burden.

nickbros123

@Arjun yeah fr I'll sleep now. I gotta wake up atleast on time for breakfast

Arjun

@naturallyInconsistent I can't understand how without understanding stuff like classical mechanics ,electromagnetism ,quantum mech and statistical mech one can do anything in physics (the above mentioned subjects I think are absolutely fundamental) and to understand all of them properly i think u still need reasonable amounts of math

And the OG's question was about being good at physics..by which i presume he also wants to learn existing physics

Obliv

I guess my question was kind of tautological in nature (if we view physics from the standpoint of relating experiences in nature with mathematics)

we could have a different idea of "physics" where we assess knowledge and understanding by something other than mathematical models

nickbros123

That's called chemistry pal

Arjun

@Obliv physics is not fundamentally math as far as I understand it ..but I just can't think of any other means of writing the laws of physics with the elegance and compactness that math brings to them

@nickbros123 we just keeping looking for an opurtunity to diss the poor chemists and biologists lol,don't we? XD

Obliv

22:22

@nickbros123 chemists use "mathematical" models in some sense though

@Arjun I think it depends on your nomenclature but most people mean it in reference to mathematical modelling of natural phenomenon that is apparently universal. Although, in my sisters college intro to physics class, they didn't use math and it was purely qualitative reasoning (sounds horrible)

That's like some eastern zen taoist stuff lol, describing things in all manner of ways.

Arjun

@Obliv I feel bad that ur sister had to go through all of that lol

Btw @Obliv are u in univ rn?

Obliv

I mean, it can be enlightening but definitely confusing beforehand. @Arjun yes, in my junior year

Arjun

Great..u majoring in physics?

Obliv

mhm, applied option right now but maybe switch to general later idk

Ryder Rude

23:17

@SirCumference this person's been uploading "physics" for years wow

@ACuriousMind yes, but a probability dist. on the classical tensor product space need not be factorisable either?

but i once read a really intriguing result about this

Obliv

What do you think "There is no deduction of points
for an incorrect answer. So even if you cannot work out the answer
to a question, you should make an educated guess." means

Silly Goose

when we say "if the action of our physical theory is not x-translation invariant, then x-momentum is not conserved". Isn't this assuming that the converse of Noether's theorem is true?

Obliv

Like they're just bonus points? context is they're talking about multiple choice questions on an exam with open-ended problems. I can't help but interpret it as saying the open-ended section is worth 100 points of the grade and the multiple choice is extra credit but that can't be right..

@SillyGoose sounds like it

ACuriousMind

@SillyGoose for a broad class of theories, the converse is true (and it's almost trivial for Hamiltonian theories), see e.g. physics.stackexchange.com/q/24596/50583

@Obliv they're just saying there's no reason not to answer a multiple choice question

sometimes you get 0 points for not giving an answer but negative points for choosing the wrong one; they're saying this isn't that kind of exam, you get zero points for wrong answers and no answer

Silly Goose

okay i see

Obliv

23:30

@Acuriousmind so you could have negative points on an exam? That sounds so hilariously horrible

Silly Goose

so is this an appropriate way to think about how dirichlet boundary conditions for a scalar field in a box of length L breaks translation symmetry?

By the imposition of the dirichlet boundary conditions, we have that the field must take a certain value at certain points of space, but this immediately breaks translation symmetry because upon translating the field, we cannot satisfy the boundary conditions

Ryder Rude

@SillyGoose i think this statement breaks down in the case of an accelerating frame. the lagrangian is $1/2mv2 - max$ but the quantity $mv+mat$ is conserved

ACuriousMind

@Obliv I'm explaining the system, not defending it :P

Ryder Rude

but this action is still invariant under translations upto a total derivative

oh so Noether's theorem directly applies. sorry

ACuriousMind

@SillyGoose think about this for a moment: How could momentum possibly be conserved inside a box? if you start with a non-zero momentum you're gonna hit the wall, and there the momentum of the stuff hitting the wall has to reverse otherwise stuff's going to leave the box!

arguing via some inverse Noether's theorem here is certainly correct but it's kinda obvious you can't conserve momentum of the stuff inside a box

Silly Goose

23:33

i do see physically that momentum must be not conserved, but I would like to be able to see it in the math, too

i guess because i would usually try to deduce if the action is translation invariant directly. but in this case information about the action is encoded in these boundary conditions, so it seems one must deduce the translation variance through finding an implication given by the boundary conditions. but it is not super clear to me how statements about a transformed field no longer being a solution translate into statements about the action

because i think it seems clear that a translated field (by a non-zero translation) simply cannot satisfy the boundary conditions, so is no longer a solution to the equations ofm otion.

ACuriousMind

I'm not really sure what the question is

Silly Goose

say i have a 1D string with fixed end points with boundary conditions $\phi(0) = \phi(L) = 0$.

suppose $\phi(x)$ is a solution. That is, it satisfies the Euler-Lagrange equation obtained by stationizing the action with the given boundary conditions.

Q1: is $\phi(x + a)$ for nonzero $a$ a solution to the E-L as well?

ACuriousMind

why are we talking about solutions to the e.o.m.?

symmetries of the action are different from symmetries of the e.o.m. which are different from symmetries of the solutions of the e.o.m.

see physics.stackexchange.com/q/51327/50583

Silly Goose

I guess I thought that is the most direct way to show if the action is not translation invariant

hm I see so I mistakenly thought that how solutions transform would tell me about how the e.o.m. would transform

okay then my question becomes this. The original boundary conditions were $\phi(0) = \phi(L) = 0$. If I translate the coordinates to the right by $a$, are the translated boundary conditions $\phi(-a) = \phi(L - a) = 0$?

i guess heuristically, i can see if I pick up my string system and spatially translate it, the system does not look the same because the boundary points at the very least have moved.

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