The h Bar

12:07 AM

@MarkMitchison , @ACuriousMind do you have any idea whether for the classical e.m. field there is a Lagrangian formalism? It seems to me that the Lagrangian formalism id for particle, and alike, but not for waves. What you say?

Mark Mitchison

Sure there is

It is the same as the quantum lagrangian

ACuriousMind

$F_{\mu\nu}F^{\mu\nu} + A_\mu j^\mu$ where $j^\mu$ is the current works classically as well as quantumly to reproduce Maxwell's equations.

Mark Mitchison

I think it is probably true that every conservative system in classical mechanics has an action formulation.

ACuriousMind

What astounded me when I first heard it is that, if you restrict the Lagrangian to really only depend on the coordinates, first derivatives and time, then the inverse Lagrangian problem is solved

We actually know exactly what the conditions on a second-order differential equations system are such that it has a Lagrangian.

Sofia

@MarkMitchison whaaat? only conservative systems? Why? Tell me please! I had, somehow, this thought.

0celo7

12:13 AM

@ACuriousMind Speaking of inverse Lagrangian problem, do you know what the Lagrangian is for a perfect fluid?

ACuriousMind

@0celo7 No idea, I don't do fluids.

Mark Mitchison

@Sofia Well if there is dissipation then there is not necessarily any meaningful action.

I don't know if I can give you a physical reason

And frankly I couldn't tell you the mathematical reason either

Sofia

@MarkMitchison you preceded me by just a seond.

vzn

@ACuriousMind lol ok no wonder AC hates the bohmian fluid mechanics stuff :\

Sofia

@MarkMitchison a dissipation system may have no Lagrangian because it's not a closed system - is that so?

ACuriousMind

12:15 AM

We've got a lot of posts on variations of the inverse Lagrangian problem, here's the latest: physics.stackexchange.com/q/167027/50583

Mark Mitchison

But it makes sense, right? Dissipation arises when you trace out degrees of freedom. So there is no reason why there should be such a "fundamental" description for a phenomenological model

@Sofia Yeah exactly

Sofia

@MarkMitchison the same as it may have no Hamiltonian, right?

Mark Mitchison

Exactly

ACuriousMind

Uh, I believe the Lagrangian description is a bit more general than the Hamiltonian

Mark Mitchison

Really?

Why?

I thought you could derive one from the other.

ACuriousMind

12:17 AM

The Legendre transform is not always well-behaved if you choose ugly Lagrangians, but the Hamiltonian is constrained by the symplectic geometry of the phase space to be a "nice" function, while the Lagrangian has no such geometrical constraint.

Sofia

@MarkMitchison I got a strange letter - please look, I quote "you, please, write to me an email. And we could continue this unfortunate dispute. –"

ACuriousMind

It's not an issue in most cases - if the Legendre transform works, you're fine

Sofia

@MarkMitchison It's a letter that "sounds bad". Someone is very unhappy.

ACuriousMind

@vzn Heh. I didn't mean I don't "like" fluid mechanics, I honestly just don't know much about its specifics.

Mark Mitchison

@Sofia Who is it from?

ACuriousMind

12:19 AM

And somehow I'm also not very interested in it. Fluids. Meh.

Sofia

@MarkMitchison Seems to be girls and she signs as zoli".

Mark Mitchison

@Sofia Haha. Ignore it

Sounds like a scam or a crazy person

Stan Shunpike

@0celo7 ping physics.stackexchange.com/questions/167099/…

@Sofia @MarkMitchison I agree. Reading letters from random people is always a bad idea.

Sofia

@MarkMitchison Mark, how can you speak so? Which ha, ha, ha? Can you go to the site and read a bit the dialogue - comments?

@MarkMitchison Mark, please!

Mark Mitchison

@Sofia Sorry I misunderstood.

What you are talking about is not a letter.

You are referring to a comment on this website.

Sofia

12:24 AM

@MarkMitchison yes. She (I suppose) seems very disappointed.

Mark Mitchison

I was laughing because you said you got a piece of random mail and were worried about it.

But I understand now that is not what you meant to say.

I'll have a look at the comment now.

Sofia

I invited her to write me personally, and she simply disappeared.

@MarkMitchison I gave her my personal email address, but she's nowhere.

Mark Mitchison

My advice is to stop worrying about it.

She is not entitled to anything from you.

Sofia

@MarkMitchison Mark, it was cruel to delete her posted question.

Mark Mitchison

If you choose to help her, so be it. She is lucky, and it's up to her whether to take advantage of that luck by communicating with you reasonably.

@Sofia I don't want to get into this discussion with you, it seems to have been coming up a lot recently

I agree with what appears to be the majority community view, namely that this site exists as a repository of good questions and answers.

Not as a help-station for everyone who has a problem

If that user is not satisfied with the answers on the duplicated question, and you think that you can help her, then you should write a new answer to the old question, and direct her there.

That means that she gets help, and the website does not get cluttered with duplicates.

Sofia

12:29 AM

@MarkMitchison the answers to the old question were fully satisfactory, by me.

Mark Mitchison

In the long run this helps more people, since every good question should have a single post with potentially many good answers to choose from.

@Sofia So why didn't you direct the user there instead of writing a duplicate answer?

Sofia

@MarkMitchison my answer that I gave her is quite similar to the answer given there.

Mark Mitchison

I don't believe what you said is true.

I think you tried to add some value for that particular user

Otherwise why write an exact duplicate?

If it really was a duplicate then why not just get the user to read the other question's answers?

Sofia

@MarkMitchison what I answered is more for beginners.

Mark Mitchison

So you should put that answer in the old question then

Sofia

12:32 AM

I mean more simply and step by step.

Mark Mitchison

Good, so put it in the old question.

Then it makes no difference that her specific question was closed.

Sofia

@MarkMitchison my problem is she. Yes, but still it wasn't clear to her.

Mark Mitchison

What we want to avoid is the following situation: someone has a question that has been asked before, they search on this site, and find 20 different identical questions.

@Sofia I really don't understand your problem. She wants an answer to a question. You gave it to her.

@Sofia Well, I'm sorry that it bothers you that much.

It doesn't bother me at all.

Sofia

@MarkMitchison she quite mocked me (I don't feel offended) that I use formulas.

Mark Mitchison

@Sofia I consider that her problem, not yours.

As far as I can tell she has a rather confrontational attitude that is obstructing her understanding. If so, then that's her problem.

ACuriousMind

12:37 AM

Asking for an explanation of why we take the tensor product without formulae is just plain stupid.

The tensor product is a formula, for crying out loud.

Sofia

@MarkMitchison she told me to write her, and that her email is at her profile site. As having less that 10k, am I forbidden to see addresses?

ACuriousMind

@Sofia No, but I think this user may not have realized that the email addresses in the profiles are only visible to the users themselves, and no one else.

Sofia

@ACuriousMind you are too young, my dear, there is another problem here.

@MarkMitchison aha! So, she wanted that I write her, not that she writes me. Strange indeed! Or, maybe something else happened.

ACuriousMind

@StanShunpike: I don't want to fill the comment section with this because I'm not quite sure what the issue is. Do you realize that, if you take a position basis $\lvert x \rangle$ of the Hilbert space (if we ignore the subtleties for a moment), the wavefunction of a state $\lvert \psi \rangle$ is just $\psi(x) = \langle x \vert \psi \rangle$?

(This is why I hate wavefunctions, so much is so much clearer in the abstract Hilbert space)

Stan Shunpike

Yes, although I will say I understand that more as a mathematical act then what it means physically.

Like, I get the idea that position space is like one way to represent the wave function and you can take a different kind of basis

ACuriousMind

12:42 AM

@StanShunpike Well, by the Born rule, if the states are normalized, then this is the probability to find the particle at position $x$.

If the states are not normalized, then it's off from the real probability by some factor

Stan Shunpike

Hmm...

I guess I should study the Born Rule more carefully and then reconsider the questions I have. Griffiths didn't really harp on that much from what I read, but it sounds like I need to make sure I understand that more clearly.

Sofia

@StanShunpike I prefer to answer you here. Is it O.K.? I saw your question "1.What was the wave function like prior to normalization? Why did it need to be normalized in the first place?".

ACuriousMind

@StanShunpike The Born rule is nothing more than the statement that, given $\psi$ and $\phi$ as states, the probability to find one state in the other is the ugly expression in my answer on the question I linked to you question. It's a postulate- Unfortunately, many texts choose to present it only in the normalized form, and then introduce the idea that $\psi$ and $c \psi$ are the same states in some other way

Sofia

@StanShunpike there is no "prior to normalization". The w.f. has to be mormalized because of what you said, its abs. square represents probability.

ACuriousMind

Normalization is really only convenience, you get all probabilities out the same if you scale everything by a factor of 3.45732

You just have annoying powers of 3.45732 floating around then, that cancel in all physical observables (i.e. probabilities/expectation values)

Sofia

12:50 AM

@ACuriousMind ah, you big mouth! You confuse the fellow!

Stan Shunpike

@ACuriousMind Oh! Okay, I wasn't sure about that. So that is an axiom then? Something we take as an assumption?

that is, the born rule?

Sofia

@ACuriousMind you see what you did? How can a probability be smth. else than normalized to 1?

ACuriousMind

@Sofia No, I am telling the truth. Stop assuming that everyone prefers feeling as if they understand to actually understanding.

0celo7

@ACuriousMind Yeah, close your huge mouth! /s

ACuriousMind

@StanShunpike Yes, the Born rule is a postulate. Given two states $\psi$ and $\phi$, the probability to find one in the other is $ P(\psi,\phi) = \frac{\lvert \langle\psi\vert\phi\rangle \rvert ^2}{\lvert \langle\phi\vert\phi\rangle \rvert \lvert \langle\psi\vert\psi\rangle \rvert }$

Sofia

12:52 AM

@ACuriousMind Aye! Phylosophy! Probabilities sum up to 1.

ACuriousMind

This probability is perfectly normalized, if you take one of the states to be any multiple of normalized position states $\lvert x\rangle$ and integrate it over the position range, you get one

Mark Mitchison

@Sofia I agree with @ACuriousMind. It is good for students to understand that normalisation is just a useful convention.

Stan Shunpike

@ACuriousMind That makes so much more sense. I kept feeling like I was missing something behind proving that notion. But now I see why the Born Rule is an important postulate. That's obviously a key idea. A key assumption.

Sofia

@ACuriousMind before teaching integrals, you teach simple algebraic calculus. Let's see him first understand simple things, and only then you make philosophy.

0celo7

@Sofia Algebraic calculus?

NeuroFuzzy

12:54 AM

so on a related note, is this why I've read some authors talk about a quantum state as a ray in Hilbert space?

0celo7

@Sofia Note that @ACuriousMind never engages in philosophy.

ACuriousMind

@Sofia Well, let me be more blunt: Stop assuming everyone is stupid. I prefer to assume everyone is smart and knows much and then turn down the sophistication of my arguments until they understand.

@NeuroFuzzy Yes!

Exactly

Sofia

@ACuriousMind , @StanShunpike which sense? I repeat, probabilities sum up to 1.

0celo7

@NeuroFuzzy Yes, we only care about the direction in the Hilbert space.

ACuriousMind

@StanShunpike Yep. It's the crucial idea of quantum mechanics.

Sofia

12:56 AM

@ACuriousMind Are beginners stupid?

ACuriousMind

@Sofia My expression up there perfecty sums/integrate to 1. It's a perfect probability, no matter whether the states are normalized or not

Sofia

@ACuriousMind if they are not normalized how do they integrate to 1 in abs. square?

ACuriousMind

@Sofia No, and this is why I talk to them as I talk to everyone else. I told you, I hate lies-to-children. And this whole normalization business has come up various times, and the issue is always that some idiot teacher thought they wouldn't understand the Born rule fully, and instead declared normalization a sacred principle

0celo7

@ACuriousMind A conventient sacred principle.

And of course conventional.

ACuriousMind

@Sofia Again, the Born rule that gives the probabilities is $P(\psi,\phi) = \frac{\lvert \langle\psi\vert\phi\rangle \rvert ^2}{\lvert \langle\phi\vert\phi\rangle \rvert \lvert \langle\psi\vert\psi\rangle \rvert }$. This perfectly sums/integrates to 1 no matter how you normalize $\phi$ and $\psi$

Which you can check in the finite-dimensional case with simple linear algebra

0celo7

12:59 AM

@ACuriousMind I'd imagine it'd be more tedious to determine transmission/reflection coefficients if you don't normalize.

ACuriousMind

@0celo7 Yes, of course, that's why we do it. It's convenient, but not necessary at all

0celo7

@ACuriousMind Does Griffiths in fact say that it is necessary?

ACuriousMind

@0celo7 No idea, but it seems he worded it confusingly enough to get @StanShunpike to assume it is

0celo7

@ACuriousMind I imagine he said something like normalization is necessary if you don't want a denominator in the Born rule.

Sofia

@ACuriousMind what you said in the long formula, is that you work with $\psi\rangle$ and $|\phi\rangle$ normalized. You didn't say anything else. So, about what you argue with me?

ACuriousMind

1:05 AM

@Sofia No, I divide by the norm of the state precisely because they need not be normalized. If they were normalized, the denominator is 1 and not there at all.

NeuroFuzzy

Yep it looks like Griffiths works with everything normalized

Sofia

@ACuriousMind It's too small a difference, for me, to argue on.

ACuriousMind

Well, but this is literally the question this was all about.

Stan Shunpike

I think understanding the Born Rule's importance was important, just for me as the OP. I often find if I misunderstand a basic, fundamental principle, it makes it hard to see how things fit together. I didn't get why @ACuriousMind had raised that in the thread he linked me to originally, but now I see why.

0celo7

@ACuriousMind Hey, what's the expression for the identity operator constructed using a unnormalized basis?

Sofia

1:12 AM

@StanShunpike but how are you taught, there is a lecturer that gives frontal lectures, and instructors that explain you exercises?

0celo7

Is it just the standard one divided by the norm?

Stan Shunpike

@Sofia I teach myself. I'm an economics major.

Sofia

@0celo7 by the norm^2.

0celo7

@Sofia Sorry, that's what I meant.

Sofia

@StanShunpike what you say! By books?

@StanShunpike do you find it interesting at all? Why do you need this trouble? QM, when you get into it seriously, begins a nightmare.

Stan Shunpike

1:15 AM

I love it, but I don't want to be a physicist. Most of my friends and family don't understand any of this stuff. They are all lawyers and economists. I just do this because I enjoy it.

My uncle can a bit.

He's a mathematician

0celo7

@Sofia I'm self taught. I do it because high school is böring.

infinitesimal

Learning from a book has its advantages

ACuriousMind

@0celo7 Uh, no, unless your basis still orthogonal

0celo7

@ACuriousMind What is the general expression then?

ACuriousMind

Oh

Wait

Sofia

1:16 AM

@0celo7 you too (my so Brutus) are self-educated in QM?

ACuriousMind

Ha, the identity operator is always just the matrix with 1 in them

Because every vector is a eigenvector with value 1 for the identity

So it is diagonal everywhere.

Sofia

@infinitesimal of course, you can take your time.

0celo7

@ACuriousMind So what are you saying?

ACuriousMind

@0celo7 The identity operator is the same in all bases. Just the $\delta^{ij}$

0celo7

@Sofia Yes, although I'm more interested in gravitational physics.

Stan Shunpike

1:18 AM

Me too! That's the stuff I find fascinating

0celo7

@ACuriousMind Of course I know that. Crap, I meant the completeness relation.

ACuriousMind

You can also see this by noting the a basis change on an operator is $A \mapsto UAU^{-1}$, but the identity commutes with everything, so $UAU^{-1}=A$.

Sofia

@0celo7 , @StanShunpike many years ago I began to study cosmology. But it repelled me. Too many theories based on too few experimental data.

Stan Shunpike

@Sofia That's one reason why I've made much less effort to learn string theory and emphasized learning fundamentals of GR, QM, and QFT first.

@Sofia Everyone seems to either believe string theory must be true or has reservations about it. And I can't tell what is true and what isn't. So I study what is known to be true based on evidence first before anything else.

Sofia

@StanShunpike what is that string theory? What for is she good?it

ACuriousMind

1:21 AM

@0celo7 Oh, you mean how to express the identity in terms of projectors?

0celo7

@ACuriousMind Exactly.

Everyone do the snow dance! Pray for snow in Virginia!

Stan Shunpike

@Sofia Like for instance, I feel like there should be a canonical argument for why string theory doesn't need to be background dependent. Like, if GR is background independent, doesn't that mean any consistent theory of gravity has to be? If that's true, how can you take string theory seriously.

But then I watch Susskind and he believes it. So I just assume I don't know enough to judge at this point. But I find it suprising there can be so much disagreement.

sorry

i meant independent***

0celo7

@StanShunpike Newtonian mechanics is Galilei invariant. Doesn't every theory of motion have to be Galilei invariant?

Old theories don't work like that.

ACuriousMind

Then you have to divide every projector by the scalar product of the basis vector, i.e. $1 = \sum_i \frac{\lvert e_i \rangle \langle e_i \rvert}{\langle e_i\vert e_i\rangle}$

Stan Shunpike

@0celo7 What's the analogy here? Does that mean just because GR is doesn't mean the deeper theory must be necessarily because GR is an approximation of some sort?

ACuriousMind

1:24 AM

(Possibly take the modulus of the denominator)

0celo7

@ACuriousMind Ha, Sofia said that a few minutes ago and confirmed my suspicion, thanks.

@StanShunpike Exactly.

ACuriousMind

@0celo7 I like that argument ;)

0celo7

Can someone please answer this question: can you right click to correct underlined words in chat?

I ask this every freaking day.

ACuriousMind

@0celo7 What underlined words? oO

0celo7

Typos

Also I forgot how to spell Galilei

ACuriousMind

1:26 AM

My typos aren't underlined, I have to spot them myself and press the up key or click edit to correct them

Mark Mitchison

@ACuriousMind Is that correct?

0celo7

@ACuriousMind Is your PC German? That might explain why words aren't underlined.

Mark Mitchison

If the basis is not orthogonal I thought the answer is not quite that simple

ACuriousMind

@MarkMitchison Oh

0celo7

@MarkMitchison I wasn't asking for a nonorthogonal basis, but that is a good point.

ACuriousMind

1:28 AM

@0celo7 Yeah, but if I make German typos, they aren't underlined, either

Are you using some sort of add-on for that?

0celo7

@ACuriousMind You using Ubuntu or something :D

Mark Mitchison

I think the answer is $1 = \sum_{ij} (G^{-1})_{ij} \lvert e_i\rangle\langle e_j\rvert$, where $G_{ij} = \langle e_i\rvert e_j\rangle$ is the Gram matrix.

0celo7

Chrome + Mac + U.S.A. @ACuriousMind

Mark Mitchison

@0celo7 Ah, but if you only wanted unnormalised vectors then what @ACuriousMind wrote is correct of course.

0celo7

@MarkMitchison "Gram matrix" :: has CFT flashbacks ::

From yesterday :D

ACuriousMind

1:30 AM

@MarkMitchison Ah. Yes. There was something about that. Not $G_{ij}^{-1}$?

God, Linear algebra was ages ago...

Mark Mitchison

Ha yeah I probably got that wrong. Lemme check

0celo7

Any ideas for a (simple) proof?

Mark Mitchison

@ACuriousMind Yes, you are right of course.

ACuriousMind

@0celo7 Hm, Firefox and Windows here. I've never seen a single word underlined in my browser in my life :D

Mark Mitchison

@0celo7 A proof of what?

0celo7

1:31 AM

@MarkMitchison That identity with the Gram matrix.

Mark Mitchison

Yeah it's really easy

0celo7

Ok, I'll try to figure it out then

Mark Mitchison

Uh well it's easy if you know how to do it...

But to be fair it isn't that hard even if you don't

I worked this stuff out for myself recently before realising there is a quicker way that I had learned years ago lol

ACuriousMind

@MarkMitchison I never know whether to feel proud or stupid when I do some two page calculation all by myself to get the right answer and then someone comes along and says, "Oh, if we apply the well-known and really easy theorem X, then the answer just comes out in one line, you know?"

Mark Mitchison

@ACuriousMind It was a mixture of both :)

Stan Shunpike

1:37 AM

@ACuriousMind I remember reading Newton did something like that because he didn't have the idea of a surface integral.

Mark Mitchison

To be fair, my proof demonstrated to me why that identity works more fundamentally than the standard trick, which appears to be "basis-dependent". Of course it eventually turns out not to be. So it was worth doing, I mean.

ACuriousMind

@StanShunpike Well, but he couldn't have just thought back to his analysis course, could he? ;)

Stan Shunpike

@ACuriousMind lolol exactly. and YouTubed it in case he needed a refersher

0celo7

@MarkMitchison I'm so used to working in orthonormal bases that I don't know what familiar formulas are right and which ones aren't. Apply $\mathbb{1}$ to $|v\rangle$: $$\mathbb{1}|v\rangle=\sum_{ijk}(G^{-1})_{ij}|e_i\rangle\langle e_j| v_k|e_k\rangle=\sum_k v_k|e_k\rangle=|v\rangle$$

Trivial, no?

Mark Mitchison

Right

It's also a lot easier when you already know the correct form!

0celo7

1:40 AM

@MarkMitchison ;)

I skipped a step where I made another Gram matrix and summed over $j$ and then over $i$.

Mark Mitchison

But if you want to see how to do it the other way, note that for any set of linearly independent vectors $\lvert e_i\rangle$, the set $\lvert f_i \rangle = \sum_j (G^{-1/2})_{ij} \lvert e_j\rangle$ is orthonormal.

This identity allows you to do pretty much whatever you want with non-orthonormal bases.

And it is one way of seeing why the Gram matrix pops up everywhere.

0celo7

Is the Gram matrix like a functional analysis metric?

Mark Mitchison

That's exactly the question I asked when I started thinking about this.

I think so, in a way.

Or at least there are very strong analogies

But here there is only one Gram matrix for a given basis, whereas in geometry there is a metric field for every point on the manifold in a given coordinate system.

0celo7

@MarkMitchison Gram field

Define at each point on the manifold a Hilbert space.

Stan Shunpike

@ACuriousMind That Born Rule thing explains what you and @0celo7 were saying the other day about why the probability amplitude had more degrees of freedom and is more fundamental. Because if you assume quantum states follow the Born Rule, that's in other words assuming such a degree of freedom exists effectively. Does that (what I just said) make any sense?

Mark Mitchison

1:49 AM

@0celo7 Sure you can do that. I'm not sure what this would really mean though. In QM you just need one Hilbert space of states for functions on the manifold (which is actually the multi-particle configuration space).

ACuriousMind

@0celo7 You can actually look at a QFT as a thing that assignes to spatial slices of a spacetime Hilbert spaces, and the path integral is the thing that gives the evolution maps between them in the time direction

@StanShunpike I'm not sure I understand what you mean. Do you mean that, by defining the probability to depend on the complex scalar product instead of some real one, we get two d.o.f. instead of one?

Stan Shunpike

Yes, and that the Born Rule postulates that is possible to do.

@ACuriousMind That's what I am saying and asking if that is correct / makes sense?

ACuriousMind

It's not wrong. I don't find it particularly clear what that means, but if you do, then go with it

0celo7

What is viXra?

ACuriousMind

6 hours ago, by Jimdalf the Grey

@Sofia viXra is an online repository, like arXiv, but they have no standards for accepting submissions, and so they have become the standard place where people with crackpot theories and awful science/math/etc post garbage papers. I'm sure not all papers are garbage on their own, but a delicious piece of chocolate cake, when found among garbage, becomes garbage

Mark Mitchison

1:58 AM

vixra.org/quant

Check it out.

0celo7

vixra.org/pdf/1502.0193v1.pdf

;D

Mark Mitchison

Highlights I can see: The Units of Planck's Constant are J not J x s: Yes or No?

That's a real brain-tickler

0celo7

@MarkMitchison 16 pages

ACuriousMind

"Memories Might be Passed Down Through Generations in Our DNA"...

0celo7

Hold up: Abstract: Yes

Wtf

I need to read this now

@ACuriousMind Assassins Creed, yo.

ACuriousMind

2:00 AM

I have the fear that this might be less scientific than AC :D

tpg2114

@ACuriousMind Although @JimdalftheGrey was relatively eloquent, I have to defer to Seinfeld:

Seinfeld - That's Garbage

►

Adjacent to refuse, is refuse!

ACuriousMind

@tpg2114 I have the feeling he might have been inspired by that

0celo7

@ACuriousMind We should encourage user 12236 to write a manuscript on there.

tpg2114

@ACuriousMind It's possible, but I don't see a citation... academic misconduct! :)

0celo7

Make it required reading to teach newcomers what shitposting is :D

ACuriousMind

2:04 AM

Nooo, now I'll spend the next minutes crawling viXra and being speechless at such profound papers like "Why life exists?"

tpg2114

@0celo7 Please leave a comment that just says "No."

ACuriousMind

The question mark is crucial there, I'm sure

tpg2114

Oooh, that paper event has the french translation of their abstract. Oui!

ACuriousMind

@tpg2114 The comment advice says: "If you are being critical you must mention at least one specific error, otherwise your comment will be deleted as unhelpful."

tpg2114

I also like how that paper uses "we" when it's a single author

Royal we I'm sure

ACuriousMind

2:05 AM

That's clever, most of that stuff is so incomprehensible that it's impossible to point out a specific error

0celo7

vixra.org/pdf/1502.0127v1.pdf

BLUE

THE PAPER IS BLUE

@tpg2114 Tell that to Qmechanic

ACuriousMind

@0celo7 A calming color to counteract your rising blood pressure while you're reading it :)

0celo7

HAHA

vixra.org/pdf/1502.0184v1.pdf

tpg2114

@0celo7 Not sure I get that reference... maybe I missed something?

ACuriousMind

The "we" in papers with a single author (and also in some with multiple ones) is actually meant to be "we" as in "you and I", and an eternal clash between people who say it sounds arrogant and people who find it nice to include the reader and "take them along on the ride".

0celo7

2:08 AM

@tpg2114 He always writes "we" in his posts.

@ACuriousMind When Qmechanic writes "We recommend book X", I always wonder who the other person is.

tpg2114

@0celo7 Ah, yeah. But like @ACuriousMind just said, I think on our site that's okay -- it's more like a "you and me" thing. But I find it oddly out of place in a paper with a single author.

Mark Mitchison

@ACuriousMind Or it's meant to be simply a formal first-person pronoun.

It doesn't need to include the reader.

You've heard of the "royal we" right?

0celo7

@MarkMitchison Including the reader in a resource recommendation doesn't make sense either.

tpg2114

Wow, apparently the "royal we" is called a nosism:

Nosism

Nosism, from the Latin nos, "we", is the practice of using the pronoun "we" to refer to oneself when expressing a personal opinion. Depending on the person using the nosism different uses can be distinguished: == The royal "we" or pluralis majestatis == The royal "we" (pluralis majestatis) refers to a single person holding a high office, such as a monarch, bishop, or pope. == The editorial "we" == The editorial "we" is a similar phenomenon, in which an editorial columnist in a newspaper or a similar commentator in another medium refers to themself as we when giving their opinion. Here, she or...

Learned something new

0celo7

@ACuriousMind Did you read "Einstein's theory of relativity cannot explain"

He lists a bunch of quantum phenomena!

ACuriousMind

2:11 AM

@0celo7 lol

0celo7

Also the 4th Maxwell equation, whatever the hell that is.

ACuriousMind

I don't read the papers, I just laugh at the abstracts/titles

0celo7

vixra.org/pdf/1502.0184v1.pdf

Read the abstract!

Who is "Maswell"

smh this is so bad.

ACuriousMind

@0celo7 It becomes even weirder when you scroll down

He defines a particle

Apparently, the crucial property of a particle is that it blinks and has an ellipse.

0celo7

Lol, page?

ACuriousMind

2:15 AM

5

0celo7

Oh wow

ACuriousMind

Really good graph on page 11

tpg2114

Is there a complete sentence anywhere in that thing?

0celo7

@ACuriousMind What is that graph?

Lorentzcontraction?

ACuriousMind

@0celo7 No idea, but it looks sophisticated :D

0celo7

2:16 AM

No space on purpose, mocking that guy the other day

Jiminion

Woit has his QM notes/book on his blog site.

ACuriousMind

@tpg2114 Yeah, but they don't make much more sense, either

0celo7

@Jiminion Huh?

ACuriousMind

Although "It is known, in line with the classical theory, that a magnetic field is created by the moving charges and electric currents." is not wrong, for example

A bit of a pleonasm there with currents and moving charges, but okay

0celo7

@ACuriousMind Obviously $\oplus_\text{ad}$ is the direct sum of adjoint algebras.

I find it interesting he's talking about relativity but I don't see any group theory, geometry or topology in the whole thing.

But it's published, so it has to be legit, right?

ACuriousMind

2:19 AM

@0celo7 Yep, it's legit

Oh god, how can the creator of this abomination of a "repository" even look one second at this site and think he's done good?

0celo7

@ACuriousMind I'm really hoping for a proof of Atlantis or Ry'leh under the Geophys tag.

ACuriousMind

Lol, "Electron is Rounder Than Predicted"

0celo7

HA

ACuriousMind

Little lepton got fat, apparently

0celo7

lol

It got on the neutron's diet

ACuriousMind

2:20 AM

Heh

And this is only the quantum physics section

Jiminion

Someone was talking about studying QM about a million yrs ago, Stan?

0celo7

vixra.org/abs/1501.0151

ACuriousMind

I'm very afraid what lurks in the "Quantum Gravity and String Theory" section

The Scientific Miracles of God Everyone Can See

Parody is impossible

0celo7

This looks half way respectable...vixra.org/pdf/1502.0005v1.pdf

ACuriousMind

@0celo7 Still not typeset in LaTeX, always a bad sign ;)

0celo7

2:23 AM

@ACuriousMind Yeah, what's up with that? Can't these people afford a free program XD

@ACuriousMind Last year in Chemistry I wrote a paper with a friend when we were bored, called "Colloquial theory"

It used GR to study linguistic evolution

ACuriousMind

@0celo7 You could publish it there!

0celo7

I should publish it

It's only slightly racist.

But it's $\Latex$...

ACuriousMind

@0celo7 Then it looks to respectable for that place

0celo7

Huh

What is the LaTeX command?

Mark Mitchison

To be fair, legitimate articles have been published on the "roundness" of the electron

ACuriousMind

2:27 AM

@0celo7 $\LaTeX$

Mark Mitchison

It's just a flashy pop-sci way of talking about the electric dipole moment

ACuriousMind

@MarkMitchison Really? Oh, well.

0celo7

@ACuriousMind The command, I know what it looks like

Mark Mitchison

http://www.nature.com/nature/journal/v473/n7348/full/nature10104.html
I also know the lead author and he's a great physicist. But it's potentially a misleading title... Got the paper into nature though!

ACuriousMind

@0celo7 \LaTeX, sorry put the dollar there out of habit

0celo7

2:28 AM

Aye, thanks

ACuriousMind

This is basically just some dude publishing how he annoyed some scientists with his ideas: vixra.org/abs/1501.0123

0celo7

I would publish it, but I don't want my real name associated with trash ;D

Both my own and theirs

ACuriousMind

I think I am beginning to understand why people watch reality TV :D

@MarkMitchison At least the very first sentence of the abstract makes it clear what they mean by "shape"

Mark Mitchison

Yeah. It's a pretty esoteric field of experimental physics but the people who are into it understand immediately what is meant by shape. So it's not actually that bad as a title. It's just that "shape" has to be interpreted carefully: it's the shape of the vacuum polarisation distribution.

0celo7

@ACuriousMind This was really quite inspired. I said that wealthy people define Killing fields of the linguistic metric tensor because their language has a smooth evolution.

Stan Shunpike

2:33 AM

@0celo7 lol imagine if u had an alterego who wrote racist, off topic trash papers just for vixra and a real self on arxiv. The physcist version of Jekyll and Hyde.

0celo7

Holy crap I put in headphones and cranked up the volume. That ping noise is deafening.

iTunes why you so quiet

ACuriousMind

@0celo7 Yep, it is. Turning it off is in the top left corner in the top right corner (if you know what I mean)

0celo7

I know that, @ACuriousMind . I just had to adjust iTunes so I can make Chrome quieter.

ACuriousMind

Okay, okay. Just mentioned it because many people seem to never look up there :D

0celo7

@StanShunpike I'd love to write trash papers when I'm bored at school.

But then I wouldn't get into any grad school in this country.

Or the western world in general.

David Z

2:36 AM

@StanShunpike that'd be an amusing Big Bang Theory episode

0celo7

"A Path Integral Approach to Ghetto Linguistics"

It's the ultimate troll site

vzn

@ACuriousMind physics is vast & agreed its hard to keep track of it all. however, you also seem to appreciate how interconnected it is... seems there are unusual "synchronicities"... eg believe there is a (as yet undiscovered) significant connection between string theory & fluid dynamics... would that make it more interesting? so, anyway, what is your favorite area of physics?

also, on the other hand, scientific compartmentalization/ reductionism can have downsides...

ACuriousMind

@vzn Uh, my favourite area? Probably quantum field theory, particularly non-perturbative aspects, although I also really like the simplicity of classical mechanics from the Hamiltonian viewpoint.

Stan Shunpike

Hear hear!

vzn

2:51 AM

yes also quite interested in the remarkable complexity inherent in "mere" classical mechanics. which possibly is still not fully/ completely known/ understood & retains some major surprises...

ACuriousMind

As to fluid dynamics and string theory...well, I don't really know either of the subjects well enough to say whether that would make it more interesting

vzn

oh thought you cited some string theory back there... this chat room is dizzying lately :\

ACuriousMind

@vzn Well, I know some string theory, but I wouldn't say I have a firm grasp on what's it about

I can play with Virasoro generators and tachyon states and perhaps compactify on a circle, but I have no clue how to get physics out of this thing.

0celo7