The h Bar

this is going down the weirdest path

I'm glad we've got on well ocelo

::grabs proton gun:: I'm gonna ionize the shit out of you, boy

othello is going at cassio my dudes

this is shakespeare in the 21st century

3:27 PM

celly

what's wrong

I don't like cancer

Right...

it's rough and gets everywhere

Okay we're taking 'cancer' as a metaphor for me, right?

metaphor? I was never good at english

Sid

@0celo7 Not all type of cancers. Only if it is a malignant tumor. It is fairly harmless if it is a benign tumour

3:29 PM

you didn't get the meme

welp

Now I'm lost

Sid

I am bad at memes. :/

sad

now ban me

For wot

Actually you did say 'sad'

that's disgusting

@heather is wise to not participate in this waste of a discussion

im going to vanish. i need to read optics. rip.

3:32 PM

@CooperCape Yes, that's a metaphor.

Glad some of my english lit stuck in

What if we use the word "metaphor" as a metaphor? r/im14andthisisdeep

thought you were 13 when was your birthday?

Also, can you?

today

happy bday

3:35 PM

@BalarkaSen That's clearly a metametaphor.

user228700

@heather Always. Always x'D

Nobody does weird quite like this chat :P

8

user228700

@BalarkaSen rip indeed.

@BalarkaSen happy birthday to you / happy birthday to you / happy birthday dear balarka sen / happy birthday to you

(pretend I sang that)

i was joking, today isn't really my birthday

user228700

3:45 PM

Wait, @Balarka: weren't you kidding about today being your birthday?

so he's still 13 smh

Tbf I keep forgetting I'm not 17 then getting sadd

@CooperCape remember that Jaden Smith post

@CooperCape Huh? What's bad about not being 17?

where he claims his physical age is 13, but his mental age is 17

that's me

i'm on a higher level of intellectual

you people don't understand moi

@ACuriousMind Oh, nothing at all it's just that everyone in my year is 17/18 and I'm just a lil' yungun

It's annoying

user228700

3:47 PM

@BalarkaSen Nobody claimed to understand you, ever :-P

@BalarkaSen You're an old time-travelling Soviet philosopher with strange artistic tastes, and you won't convince me otherwise

@BalarkaSen Ahh Jaden

Hair of the angels

@CooperCape Ah, I can relate, I was the youngest in my grade, too

Becoming 17 won't help with that because the others age at the same speed, though :P

It's a real bummer - but in a way it will 'cause then I can actually drive finally

Q: Why are my posts being rated negatively?

@ACuriousMind Says the AI running in deep learning algorithms. Pshaw.

Physics Meta

4:11 PM

0

I have a question about my Physics Stack Exchange post: Screw falling in an elevator I haven't used this site much before but I asked two questions recently which were both rated -1. I have no idea why this could be and there was no constructive feedback left by the people who rated them neg...

support specific-question down-votes

4:39 PM

Alright, time to get off the internet and to the party - Guten Rutsch everyone (as we say here) and I'll see you in 2018!

see you in 2018 @ACuriousMind =)

user228700

@ACuriousMind See ya! :-) Have fun!

Elder Scrolls IV: Oblivion Soundtrack

4:55 PM

why does he leave when I have constraint questions

John Rennie

My last answer of 2017. Goodnight and see you all next year :-)

Avantgarde

►

Prathyush Poduval

5:24 PM

The new year party here has nice food, my stomach had a wonderful time

Can’t wait for next year now

5:37 PM

New year has started. It has been over one hour since the new year. But is it any special?

@Slereah what questions?

@Sid 7 times

The people gathering to celebrate in front of the city center have gradually scattered.

@0celo7 Apparently the constraint on particle momentum for the Polyakov action comes from the reparametrization gauge

I had Questions on the matter

Hm, actually i think Henneaux has a chapter on it

4.3

@CaptainBohemian Of course it is! 2018 is the only number which can be written as a product of 2018 and 1 in exactly two ways!

Prathyush Poduval

^Ramanujan Jr

5:45 PM

This man recognizes talent

ooolb

i miss 2017

@BalarkaSen I’ve never thought that was very funny. More like the insane ramblings from a dying man.

@BalarkaSen 2018=2x 1009

@Captain Less interesting than what I said

Still I'm not 100% sure why the Polyakov action gives rise to the constraint $$p_\mu p_\nu g^{\mu\nu} - m^2 = 0$$

Due to reparametrization invariance

5:48 PM

@0celo7 Ironically, it's a joke on the insane ramblings of a dying man

(Ramanujan)

@BalarkaSen I don't understand exactly what you mean. what are the two ways?

2018 = 1 x 2018 = 2018 x 1 !!!

@Slereah isn’t this in BBS?

Obviously $$\det \left( \frac{\partial^2 L}{\partial \dot e \partial \dot e} \right) = 0$$

since there's no dependance on $\dot e$

@0celo7 BBS?

Prathyush Poduval

2018 x 1 is 2019, minus one that 2018 free quick mahts

5:49 PM

Becker Becker Schwarz

I do not know that book

It’s only the most famous string theory book

I only got Polyakov

my dude

Errr

Polchinski

What's with string theory and the pol names

@PrathyushPoduval +1

There's no momentum for the einbein, tho

5:52 PM

Just download BBS

Since $p_e = \frac{\partial L}{\partial\dot e}$

Aight

It probably explains this

I mean

I will buy it legally

It’s a pretty bad book otherwise

@Slereah I have a copy that props up my computer case

The cover does look trippy

Doesn't seem to cover that constraint business

I mean they get the same equation just by variation

But this is for Hamiltonian business

5:56 PM

Random CTCish question:

Does there exists "attractive CTCs", i.e. CTCs such that any worldlines passing in its vicinity will converge and then get trapped in the CTC?

More illustratively: Picture a region of spacetime with a CTC. Any worldlines that pass near it will converge to the CTC region and cannot escape

thus a spacetime with a geoemtry that is something like a mix of a gravtiational well and a CTC

Though apparently constraints for parametrization are common in Hamiltonian mechanics

So I should find something

That should be in QoGS

yeah it kind of is

But QoGS is not a good place to learn about constraint mechanics

Possibly a good place to learn about BRST quantization

but

Constraints

not so much

It's a bit dry

This is a simple example that I can think of that illustrate the idea:

In the middle of this cylindrical spacetime is a CTC

I only know two special things for this new year. One is the supermoon livescience.com/…, another is the Sirus reaches its brighest in the midnight of new year earthsky.org/astronomy-essentials/…, but the whole sky here is gray, so I can't see any celestial objects.

6:08 PM

The curvature is such a way that if you start at anywhere off the middle, then as time progress you will spiral in towards the middle and stuck there

Example trajectory

I wonder if there are GR solutions that behave like that

what on earth is CTC abbreviated for?

Closed timelike curves

Slereah is an expert on that

More generally, I think I am looking for non black hole spacetimes such that all geodesics converge to some finite region of spacetime with various geometries such as a CTC

is it related to cohomology group?

that I am not sure

Wonder what this symbol is gyazo.com/aec0dbac0f06bf44765f2dbc7c2b779b

Probably a script H

6:20 PM

CTCs are related to the homotopy group

They're part of the timelike homotopies that can't be deformed to the identity

But then again almost nobody uses the timelike homotopy group

I've seen maybe 5 places using it

7:03 PM

@0celo7 that's so obviously the goat symbol

As an example of vector spaces this author says "Let $S$ be any nonempty set and $F$ be any field, and let $\mathcal F(S,F)$ denote the set of all functions from S to F", what's the deal with calling $F$ a field? Is it just so that addition of functions is defined?

can u finish the definition, so far there's no reason $F$ has to be a field

so far it's just a couple of statements about what the symbols mean

What are you reading

I think i realised while typing it out why it's a field

kudos

7:09 PM

if you have functions $f,g \in \mathcal F$, then for them to be elements of a vector space the elements would have to, as one of the properties of a V space, be able to be added together. So that's why it has to be a field instead of a set?

first time picking up a textbook in too long so my brain is covered in rust

apologies

vector spaces are defined over a field (usually $\mathbb{R}$ or $\mathbb{C}$), that's pretty much just part of the definition...

If it’s a field then it will be a vector space over that field, yes.

Yeah ik, that's why my question was dumb. I didn't see why the domain could be a set but the range had to be a field, but then I realised that it would have to be to able to add functions

@Phase It's an interesting question if you modify it, actually.

Suppose $X$ is a bare set. No other structures, nothing. Just a set.

right

If it's a naked set shouldn't it be $XXX$

7:14 PM

ayyyyylmao

lol

phase get your mind out of the gutter

We're all lying in the gutter some of us are just content to stay there

cant do math and finna bass at the same time bro

Is there more to the question? x)

Ah, yes, so here

Consider the set $\text{Map}(X, X)$ of all maps $X \to X$

The interesting but vague question to ask is what kind of an object is this? What structure does it posses?

One observation is the following

Suppose $f, g \in \text{Map}(X, X)$ are two arbitrary elements of it. Then there is a way to get another element of $\text{Map}(X, X)$ out of them; namely, compose: $f \circ g$

If you want to go super abstract and meta about it, this gives you a map $\text{Map}(X, X) \times \text{Map}(X, X) \to \text{Map}(X, X)$, which eats two maps $f, g : X \to X$ and spits $f \circ g : X \to X$

7:18 PM

any hints? : P not entirely sure where to start or what to consider

Which is... kinda trippy, right?

@Phase Ah, it was a vague question I was throwing at your general direction

I am trying to walkthrough you to an answer

question about notation

how come its not

Nevermind just realised

@BalarkaSen please stop

@BalarkaSen who was the philospher that has the same ideas about evidence that I do?

@ACuriousMind recommended him to me but I can’t find it in the transcript

Alex Jones?

^

7:21 PM

No

English guy I’m pretty sure

@ACuriousMind pls

@0celo7 Duffield

Please be serious

Also what ideas

They probably don't bear repeating

Evidence is worthless unless you observe it yourself

@Phase delete your account

7:24 PM

Ok

here goes for the 9th time

Epistemologically sound but practically of little interest

@Phase gg

I don't think you have time to repeat every experiment of the past 500 years

gg no peepee as the kids say

Osal Selaka

Happy new year for all, my sack exchange family, be a nice year, wish to success your all educational dreams.

7:26 PM

@phase did u see my thing

@BalarkaSen please dont respond to a message with "peepee" in it with "did you see my thing"

I don't want the feds at my door, given you're like 12 years old

fucking hell

@OsalSelaka how kind! Same to you

@BalarkaSen do I even want to know what homotopy groups of an abelian group is

Loong

@BalarkaSen ?

I think my colleague still has a case of that stuff.

7:31 PM

@0celo7 By abelian group you mean an abelian topological group

@BalarkaSen i mean the group of integral k-cycles

I have no idea what the topology is supposed to be

“Compact Open” is not something I want to hear

I don't know what topology you have in mind

I don’t either

They don’t say

send the author a passive aggressive email

or an aggressive email

or a brick

7:35 PM

Or a dirty bomb

"The identical equation was proposed independantly by Gordon, Fock, Klein, Kudar and De Donder and Van Dungen"

We should really call it the Schrodinger-Klein-Gordon-Fock-Kudar-de Donder-can Dungen equation

I don’t have Federer on my phone. What bullshit is this?

I'm still trying to figure out why Klein Gordon doesn't work in RQM but quantizing the Polyakov point particle does

What kind of madness is this

I guess I need to compute the probability current of the Polyakov one

"We conclude that a consistent theory can be developed for a free particle if we adopt the manifold of positive energy solutions as the set of states which are physically realizable by a free particle."

Hm, could be related

@BalarkaSen there’s a reason why you don’t know what the topology is

@0celo7 Hume

7:48 PM

It’s a metric topology in terms of comass of forms

@ACuriousMind thanks

"the ghost states are labeled by $\uparrow$ and $\downarrow$, corresponding to the unique 2-dimensional irreducible representation of the ghost algebra."

Not the ghost algebra

It's the scariest of all algebras

Lmao

math should be themed

when it's Halloween season for example, all math should be translated to Halloween themed language.

would be awesome

Hm, apparently when you do the fancy Dirac quantization of a point particle

You have to change the definition of the inner product

Due to the gauge issues

$$\langle \psi_a, \psi_b \rangle = \int d^nx\ (\psi_a)^* \delta(\Upsilon) \left\{ \Upsilon, \Phi \right\} \psi_b$$

I wonder if it's related to the issue

Except after doing all the gauging you just get the Klein Gordon inner product!

Which is indeed possibly negative

8:06 PM

is Polyakov line (loop) just Wilson line (loop)?

No

Hm, is the reason why it work just the usual QFT chestnut about causality?

That we restrain the momentum operator to the front light cone

Or something like that

Bernardo Meurer

You know

Even after learning Rust, Python, Go, and all these new languages

C is still my favorite I think

It's just such a joy to write

@Slereah that looks like fake math

Is it because there's an upsilon

yeah perhaps

Bernardo Meurer

8:19 PM

Who even uses Upsilon

More importantly does that issue pop up for the string action, too

Maybe I should look into that

@Slereah Title: What is the mass of spacetime? Abstract: We show how to obtain global invariants of asymptotically flat, globally hyperbolic Lorentzian manifolds using the ADM splitting and Noether's theorem.

Are presentation abstracts that short?

the organizer likes them very short

for example: "We show that, up to rigid motions, there is a unique compact, convex, rotationally symmetric, ancient solution of mean curvature flow that lies in a slab of width $\pi$ and in no smaller slab. This is joint work with Mat Langford and Giuseppe Tinaglia."

@enumaris "be sure to take the vampire product of the skull vector"?

8:31 PM

something like that

indeed

now i'm just imagining math operations sung to christmas carols