The h Bar

user507974

00:25

hey guys, whats the best book on diffusion you guys have read, something preferably approachable for someone who's done some diffusion but really wants to understand

user54412

02:48

And I'm pretty sure this proves the OP really was just out to give voice to his own misunderstanding.

user116211

05:02

Hey @David; have a look in this answer of Alfred:

user116211

8

A: What are the accelerations of blocks?

Let the initial length of the bottom segment of rope be $l_1$, the initial length of the middle segment be $l_2$, and the initial length of the top segment be $l_3$. Since the total length of the rope is constant, we can write $$l_1 + l_2 + l_3 = K$$ Now, displace the block $A$ by $\Delta x_A$...

user116211

Albeit a nice answer, but a complete solution to OP's HW question.

user116211

I'm not sure when we have started to get deviated from our policy not to post complete HW solution.... can you provide me some insight on it?

user116211

06:10

Sometimes, I wonder why some people meddle QFT with QM.

user116211

@DanielSank: o/

user116211

Don't know.... but CuriousOne sometimes really bothers me a lot with his comments.

Secret

06:31

alternet.org/environment/…

@MAFIA36790 although he seemed to dampen his emotions a lot in his recent comments that I came across

user116211

@Secret: Well, let me show my recent spat with him:

user116211

I wrote "There are only quanta associated with quantum FIELDS" and I don't think that was unclear, either. I wasn't arguing that we need to resurrect matter waves. We have replaced "particle" with "quantum" and "wave" with "field". These fields do not, in general, behave like simple scalar of vector fields. These fields ARE matter and they have mass, charge and energy. The problem is that much of non-relativistic QM terminology is stuck in limbo, where it's not completely false but the "probability to find a particle" terminology is just false enough to cause plenty of confusion. — CuriousOne 17 mins ago

user116211

He just disagrees with the interpretation of wavefunction probability to find a particle....

user116211

I know he is not saying wrong, but please don't meddle always QM with QFT.

user116211

I am aware that most introductory texts are still doing it like that. Did you notice the resulting confusion? A modern textbook that doesn't start by explaining the differences between these terms is failing the student IMHO. There is nothing wrong with the probability interpretation, but one simply can't say it's "the probability of a particle being at x". — CuriousOne 5 mins ago

user116211

06:38

My reply:

user116211

@CuriousOne: I know electron is not classical particle; however that entity is described by wavefunction. And there is Born's interpretation. That's the crux of QM. I know the wave-particle duality fades away in QFT. But see you can't just impose QFT without learning the basic interpretations of QM. — MAFIA36790 1 min ago

user116211

@Secret:Any opinion?

Secret

Well at least to me, I only see the emotions localised on his position, which is a lot milder than the sarcastic style in the distant past (The strongest one is localised at the phrase "Did you notice the resulting confusion?").

However both of you guys seemed to have presented your position on the issue clearly, thus it is a reasonable discussion, if a bit heated

As for the context itself, I don't really know because I still yet to formally learn QFT. We are always taught in the sequence of QM followed by Relativistic QM and then QFT. That's a reasonable sequence because the concepts ar…

nature.com/ncomms/2014/141219/ncomms6814/full/ncomms6814.html

For me, because I too was following the learning sequence of QM->RQM->QFT, I will find that the concepts flow smoothly and builds upon the previous along this sequence, thus justifying your point

However, I and my friend have not investigated about the reverse possibility. If it was shown the concepts to be flowing smoothly, then it can be justified to start piloting a QM course by starting from QFT concepts

user116211

@Secret That's my point, but he doesn't seem to understand.... he used the phrase dead and buried terminology of WW I era physics to denote the interpretation of wavefunction. I've re-iterated that QM is different from QFT.

Secret

06:56

**dead and buried terminology of WW I era physics** This is an emotional adjective phrase and I tend to filter it out because it only serves to emphasize the issue but not giving facts on a position

The reason I rarely get enraged when having discussions with highly emotional people (obviously not talking about you two here, or anyone else on this chat, for you guys are much milder than those examples I encountered) is because I naturallyl filter away irrelevant emotional terms, thus in a sense I don't see their emotions and focus on addressing their positions

Secret

One thing that makes me appeal to my friend's speculation of reversing the teaching order of quantum courses is that (at least based on my extremely limited understanding), unlike GR vs Newton gravity, QM and QFT can in some sense be treated as special cases of each other, due to their very general concepts of a state and a field

Thus I hypothesize that the concepts may turn out to flow smoothly regardless of which end you start at

but otherwise, I knwo so little of QFT to justify this speculation, other than it is a curious possibility to test out

DanielSank

@MAFIA36790 \o

Secret

@MAFIA36790 To help on the discussion, can you give me an example of a concept in QFT that cannot be smoothly flow into QM by treating it as a special case?

DanielSank

@MAFIA36790 me too. All the time.

I think teaching students single particle quantum mechanics with first quantization as the first step is a mistake.

Secret

@DanielSank What concepts do you think we should teach students about first to get them ready for quantum physics in general and to ensure it flows smoothly to the more advanced stuff?

Secret

07:26

/

Secret

There's only one thing I found annoying in a discussion: People's beliefs can cause them to only see things they want to see, while I will always try to address every single line they wrote in order to not miss out a position to be addressed and hence increase my understanding to the problem.
This rarely happens in reality, because they don't have a choice to ignore things that conttradict their beliefs and is forced to face them

> Next time, when I make a discussion like this, in order to increase the coverage and scope of the issue, I will stop presenting both sides of the argument in one post, and will only present the side that agrees with them only when they have address the one that contradict their positions first

I hate to say that, but I really have to treat other people in a manipulative manner due to the human nature of bias, thus some trickery and psychological framing is needed in order to interrogate their bias to critically analyse the issue they don't like

Remember, when it comes to increase the understanding of something, and to shot down my pet theories, I am merciless to everyone including myself

After all, we are just extremely advanced quantum computing watery bags of chemicals, what reasons should we treat each other as human beings?

and not devices that store and exchange knowledge?

(by this line, you should have noticed something looming)

The is really only one thing that can stirr my emotions, and that is when the truth refused to reveal itself or is withheld due to bias

This is because my purpose of life is to unlock the mysteries of nature, and nothing will stop me from achieving that

David Z

08:09

@MAFIA36790 and where exactly does it say we have deviated from our policy not to post complete solutions?

user116211

08:24

@DavidZ Remember when I posted a complete solution, you deleted my post and said it is against our policy not to post complete HW solution... did I misinterpret something?

Slereah

Oh wait

I think I finally got what the "indefinite" path integral is for the propagator

From Peskin it seems to be

$$\int \mathcal{D}\varphi(x) = \int \mathcal{D}\varphi_1(\vec x) \int \mathcal{D}\varphi_2(\vec x) \int_{\varphi(x^1_0, \vec{x}) = \varphi_1(\vec x)}^{\varphi(x^2_0, \vec{x}) = \varphi_2(\vec x)} \mathcal{D}\varphi(x)$$

You just do it over all boundary conditios

Secret

@MAFIA36790 What is the most different concept in QFT that cannot be back-generalised or narrow down into QM? (Or put it in more comprehensible terms, what is the concept in QFT that has no counterpart in QM even if we consider constraints like assume non relativistic etc. etc. etc.)?

user116211

08:39

@Secret Don't ask me, ask CuriousOne ;P

Slereah

All of QM is done on the same Hilbert space

You can't do different QFTs on the same Hilbert space

David Z

08:53

@MAFIA36790 again, what makes you think we have deviated from our policy not to post complete solutions?

user116211

@DavidZ okay, is it favourable to our policy to post complete HW solution?

David Z

Why would you say that?

user116211

@DavidZ Because it's HW question; we are not homework helping site, are we?

user116211

So, is it not against our policy to post complete HW solution?

Slereah

If we were a homework helping site I'd prefer getting paid for it :p

David Z

09:00

@MAFIA36790 again, why would you say that? I still don't understand what would make you think it's not against our policy to post complete solutions. Have you read the policy? Do you not understand it?

yuggib

@Slereah all separable hilbert spaces are isomorphic, let's say you can't do all QFT in the same representation of the algebra of observables

Secret

Curiousone cannot answer that because his position is QFT->RQM->QM, while you are QM->RQM->QFT

In order to explain why it is QM->RQM->QFT, the logic must say that there must exist a condition that QFT->RQM->QM will lead to problems such as the concepts cannot flow through and build upon the previous smoothly. Usually a person holding the position that QM->RQM->QFT will be more readily see why the alternate is not possible (if any) because of the confirmation bias will select things that support one's conclusion

user116211

@DavidZ Have I said it's not against our policy to post complete solutions ?

Slereah

The problem of RQM is that all RQM theories are required to only have probabilities of 0 :p

David Z

@MAFIA36790 that's what you're asking about, right?

Secret

09:03

@MAFIA36790 In a similar logic, only @CuriousOne will be more readily able to explain why QFT has to come before QM

user116211

@DavidZ No!

David Z

@MAFIA36790 then what did you mean by "is it not against our policy to post complete HW solution"? Or I guess the more important question is, what are you asking? I still don't understand.

0

Q: What's the probability distribution of a deterministic signal or how to marginalize a dynamical system?

In many signal processing calculations, the (prior) probability distribution of the theoretical signal (not the signal + noise) is required. In random signal theory, this distribution is typically a stochastic process, e.g. a Gaussian or a uniform process. What do such distributions become in d...

0

Q: Is there a Bayesian theory of deterministic signal? Prequel and motivation for my previous question

This is a prequel to my question: What's the probability distribution of a deterministic signal or how to marginalize a dynamical system? Clearly my question looks at the same time fairly elementary but completely unexpected, even crazy, out of nowhere. That's probably the reason why I did not ...

mathematical-physics probability integration signal-processing non-linear-systems

^^ on topic? They've already been posted to MathOverflow

user116211

@DavidZ: embarrassed

Secret

This is a valid assumption to assume both people in a discussion to be not rational enough to see both sides, in order to take full advantage of the confirmation bias in giving me important information to highlight the details of the issues, after filtered by cross checking

user116211

I have used double negation in a sentence to make it affirmative.... damn, sorry about that @DavidZ

Secret

09:06

Even I am a human, thus I can never say I have fully account for both sides, but I have tried my best

user116211

Posting a complete HW solution is against our policy, isn't it, @DavidZ?

Secret

@yuggib Ok that makes sense

yuggib

anyways, the picture in QFT and QM is not different in principle

but systems with a classical phase space that is finite dimensional are easy

ones with infinite dimensional classical phase space are not

David Z

@MAFIA36790 that's the same thing you asked before. My response is the same: yes, our policy is that people shouldn't post complete answers to HW questions, and I don't understand why you are doubting that.

user116211

@DavidZ Because Alfred posted a complete HW solution; check the post above.

David Z

09:13

Yes, and what relevance does that have to the policy?

Or, how is that reason to doubt what the policy actually says?

user116211

@DavidZ I have no doubt now that you said ' yes, our policy is that people shouldn't post complete answers to HW questions '. But he posted a complete HW solution. Isn't then his answer violating the policy that people shouldn't post complete answers to HW questions ?

David Z

Yes... I would think that should be pretty clear

user116211

@DavidZ Ah! I see the question now;

user116211

kudos to David

Secret

I cannot seemed to be able to ping @CuriousOne, and I don't recall doing anything that will cause him to block me

user116211

09:22

@Secret He didn't come here recently....

Secret

O I see

David Z

@MAFIA36790 still not sure I get it, but that doesn't matter; good that you understand

user116211

@DavidZ The policy was clear to me; it was just that I messed up my grammar there at that particular sentence you were quoting. Thanks for your wonderful job.

lucas

10:01

@DavidZ Hello dear David Z. May I ask you why you block my questions, answers, etc? Do you have problem with me while we don't know each other?

Danu

@lucas I don't think that David, or any other particular person, has the power to personally block your questions or answers, unless you mean banning you from the site (which is not the case).

user116211

@lucas No one has problem with anyone. Please read our SE policy....

lucas

@MAFIA36790 May I ask who are you?

user116211

@lucas what?

Secret

In MTW, everything are eggcrates

lucas

10:09

@MAFIA36790 Everyone says read "our" SE policy. Who is this "our"?

user116211

@lucas The community

lucas

@MAFIA36790 Are the"our" great scientists even greater than Gauss or Newton?

Danu

@ACuriousMind o, the right way is do that summation trick I'm so happy about :@

user116211

@lucas wth are you saying?

lucas

@MAFIA36790 Do the "our" have all of knowledge in the world?

Danu

10:11

@lucas It sounds like you're looking for a confrontation, from the things you're posting. Please don't.

user116211

@lucas: Can you provide link that specifically bothered you?

user116211

If you think, there is any problem or any unfair CV or just all sort of that, you can air your grievance at Meta.

lucas

@MAFIA36790 Nothing bother me. I want to help the others. But I cannot understand the"our"'s goal.

user116211

@lucas Exactly what is bothering you? Can you elaborate?

Slereah

I have all the knowledge in the world

lucas

10:16

@MAFIA36790 I said nothing. But I sense that some of the "our" think that all of people beyond the "our" are stupid.

user116211

@Slereah ::sending my men to kidnap @Slereah::

lucas

@Slereah Congratulations.

Slereah

Thank you.

user116211

@lucas You are misinterpreting things, I suppose.....

Slereah

It took a while but it's all in the reflexes

AccidentalFourierTransform

10:18

@Slereah you mean you read these:

Slereah

I read the junior woodchuck manual

user116211

@Loong: o/

lucas

@MAFIA36790 Maybe I am wrong. But I don't think so. Because of my observations.

Loong

@MAFIA36790 hi

user116211

@lucas what observation?

user116211

10:21

Listen, you've to follow certain guidelines here.... SE is neither a forum, nor a HW solving site.

lucas

@MAFIA36790 The "our" treatment with me.

user116211

@lucas Why not provide a link here to that specific question?

lucas

@MAFIA36790 May I ask what is SE's goal?

user116211

-3

Q: Is this a paradox?

Suppose we have two equivalent rigid cylinders. Cylinder 1 is moving (translating) with constant velocity of v. Cylinder 2 is rotating without slipping and its center’s velocity is constant and equal to v. So, the motion equations of both centers of cylinders are same (x=vt). If I am wrong, pleas...

kinematics rotation rotational-kinematics

user116211

@lucas: Is this bothering you?

lucas

10:23

not only this.

Slereah

Oh wait no

Apparently the vacuum expectation value in path integral is just $\lim_{t \rightarrow \infty}$

Hm

lucas

@MAFIA36790 I answer questions and David Z deleted them.

Slereah

Do boundary conditions not matter at all in those circumstances?

AccidentalFourierTransform

@Slereah IIRC the boundary conditions are imposed by the $\epsilon$ "trick"

user116211

13

Q: What is the ultimate purpose of physics.stackexchange?

I'm a newbie here and I've noticed that a lot of the questions are at a pretty high level. (I'm just starting a masters program in physics). Does this site have a philanthropic goal of speeding up the research process or is it merely an experiment in social media? Is it a site that aims to impact...

discussion

Slereah

10:25

Oh yeah it's the trick that in the limit $t\rightarrow \infty$, the term $e^{-iHt}$ is dominated by the lowest energy

lucas

@MAFIA36790 If I tech a student something, am I get wrong?

Slereah

Which is, hopefully, the vacuum

I see

user116211

@lucas Deleted them.... want to know why?

Slereah

I should try to answer that question of mine with LFT :

10

Q: How to deal with boundary conditions for path integrals?

For non-relativistic quantum mechanics, the boundary conditions are rather simple to deal with, they are just \begin{equation} \langle x_1, t_1 \vert x_2, t_2\rangle = \int_{x_1(t_1)}^{x_2(t_2)} \mathcal{D}x(t)e^{\frac{i}{\hbar}S[x(t)]} \end{equation} And then we can solve the path integral by...

quantum-field-theory path-integral boundary-conditions

lucas

@MAFIA36790 If I tech a student something, am I get wrong?

user116211

10:27

@lucas Because we are HW solving site.

lucas

@MAFIA36790 What?

user116211

26

Q: What is the policy here on homework?

Possible Duplicate: Homework on StackOverflow I am not a student, but I know other avenues have had problems in the past with students trying to get others to do their work for them. I am sure most of the people on this site right now would not give a student the code they need to comp...

discussion homework

AccidentalFourierTransform

@Slereah have you read Weinberg? I think your question is addressed there...

Slereah

It is, yeah

AccidentalFourierTransform

when W. introduces path integrals

Slereah

10:28

I have seen it

But even Weinberg doesn't do actual examples with boundary conditions

user116211

Also @lucas:

user116211

256

Q: How do I ask and answer homework questions?

Please note that the homework tag is now officially deprecated. The homework tag should not be applied to new questions and may be removed from old questions. Can and how does one ask about homework, and what guidelines should members use when responding to homework questions? Return to FAQ ...

support etiquette homework

Slereah

I think it's doable with LFT

I'll have to try it

Peskin derives the propagator with LFT

user116211

And finally @lucas:

user116211

63

Q: How do I ask homework questions on Physics Stack Exchange?

What is the policy on asking homework questions on Physics Stack Exchange? What kinds of questions are considered homework questions? Are homework questions allowed? What should I include in a homework question? Why don't you provide a complete answer to homework questions?

discussion faq homework

Slereah

10:29

Gonna try to go from there

AccidentalFourierTransform

lol what is LFT

acc to google, Liver function tests

lucas

@MAFIA36790 Anyway. Leave them. Do you know what is the "our"'s goal?

Slereah

Lattice field theory

But first

I need the most important tool of physics

A NOTEBOOK

Or I could do it in Latex maybe

that way I can answer on SE easily

Danu

Take all notes in TeX

BECOME THE MACHINE

(I actually do this)

user116211

25

Q: Is the ultimate goal of Stack Exchange really to build a knowledge base for Googlers, not to help individual users (even if they ask good questions)?

I often hear the argument that the end goal of Stack Exchange is not to provide individual answers to questions, but to act as a knowledge base for people coming from Google: You are just completely missing the point of SO. It is not to give an individual user help. It is to give the legion o...

discussion stackexchange

Slereah

10:32

Do we have an ultimate goal

AccidentalFourierTransform

"Our"
https://i.ytimg.com/vi/eb1A4KmVJME/hqdefault.jpg

Slereah

Is it sinister

user116211

But remember @lucas, we are not homework solving site and neither we are any forum; so don't post complete solution to HW questions.... that's why your answers got deleted.

Slereah

Also time to make some hamburgers

lucas

@MAFIA36790 Can't you say to me easily and briefly? My English isn't good and I use dictionary at the moment.

@MAFIA36790 What is your goal?

user116211

10:34

@lucas my goal? What do you mean by that?

lucas

@MAFIA36790 Aren't you one of the "our"?

AccidentalFourierTransform

everybody knows that our goal is sex, drugs and money.

we are theoretical physicists for gods sake

user116211

I come here: learn new things; shun away confusions reading others answer; sometimes post answers to those I know about; ask questions; review to make clear the site of rubbish posts @lucas

user116211

@AccidentalFourierTransform Where is John?

lucas

@MAFIA36790 How do you judge about answers and questions (especially when you downvote them)?

user116211

10:42

@lucas Hmmm, I at first see what OP is asking; if his query is conceptual-oriented, then okay.....

lucas

@AccidentalFourierTransform Forgive me but I think you are full people.

user116211

If OP is asking homework questions, then I first see whether he showed effort at all and most importantly whether the query (again) is on some conceptual problem or not.

user116211

If not, I vote to close it on the specific ground.

user116211

Question must show some research efforts and a conceptual query in it

user116211

Questions which can be easily answered using google or that is not encouraged here.

lucas

10:45

@MAFIA36790 Are you certain that you right? Maybe there is something that you cannot see.

user116211

@lucas I'm not saying I'm always right.... I made mistakes sometimes and I confess that.....

user116211

And that's why a question needs five votes from different users to get closed.

user116211

Sometimes, mod interfere by supervoting to close them; but that's not often.

lucas

@MAFIA36790 Do you know Niels Henrik Abel?

or Évariste Galois?

user116211

@lucas know both one. Why?

AccidentalFourierTransform

10:49

@lucas honey, you are neither

lucas

@AccidentalFourierTransform No I am not. But I think you are new Newton or maybe new Gauss or even combination of them.

AccidentalFourierTransform

@lucas I have never downvoted anyone

lucas

@MAFIA36790 Did you read his biography?

user116211

;_; @lucas: you didn't get anything from this conversation, did you?

user116211

@lucas No; but the later died in a gun duel; I know that.

user116211

10:53

::nominating @AccidentalFourierTransform for Nobel Peace Prize::

lucas

@MAFIA36790 I cannot say what I want to say because of my poor English. But I suggest you to read biography of both of them. And then be careful when you judge.

user116211

@lucas You DON"T have to worry about my judgement!

Slereah

Evarix le gaulois

user116211

It's a pity that the conversation didn't become fruitful to your side @lucas!!

lucas

@MAFIA36790 Forgive me if I bother you. Thank you for your time and attention. Good luck.

AccidentalFourierTransform

11:05

@lucas au contraire: you bothered no one, its a good thing that you want to discuss these issues!

you feel that you are being mistreated, which would be a bad thing

(he already left the chat, right?)

Danu

13:22

@AccidentalFourierTransform Why not?

Jacobadtr

Are the lower energy microstates of a system of particles considered to be accessible in the high temperature limit?

I think that they would be, just with decreasing probability as T increases.

Danu

13:37

→ 2 messages moved to Trash

@JohnDuffield If you want, I can move those messages to a different chat room if you make one. Let me know.

AccidentalFourierTransform

@Danu I dont know. If I think a question is off-topic, I vote to close it. If I see an answer that I dont like, I tend to think that I might be wrong and I prefer to comment

Danu

@AccidentalFourierTransform All up to you, of course, but I think it's better to focus on what you think is "good content". If a post is not "good content" (you have to personally decide what that means), then I think a downvote is appropriate.

John Duffield

@Danu : What I'd like you to do is a) moderate untrue derogatory comments b) allow me the right of reply and c) avoid censorship of my reply whilst leaving the untrue derogatory comments for all to see.

David Z

@AccidentalFourierTransform Commenting is good, yes, but if you see something that's wrong or not useful, it helps to downvote as well. That's the whole point of Stack Exchange, as opposed to other sites: we actively try to exclude and eliminate bad content.

John Duffield

14:07

@DavidZ : only you just moved this, which says the concept of particles/antiparticles constantly appearing and disappearing is a common misconception. You exclude and eliminate good content.

ACuriousMind

14:50

@AccidentalFourierTransform While it's of course your decision to not cast downvotes, I still stand by what I wrote in this meta answer. There are not enough downvotes cast to counteract the upvotes that even rather bad content gets.

Slereah

Yeah but on the other hand

Very downvoted answers are rather unlikely to get deleted

Even if really terrible

Meaning that in the end it is sort of points thrown to the wind

ACuriousMind

Well, I'm not sure I want them deleted - that would reverse the reputation loss the poster incurs from getting downvoted

Slereah

Especially since you can't even affect noticably the reputation of someone with them

So really it is more interesting to upvote good answers than downvote bad ones

ACuriousMind

I'm not saying to upvote less good stuff! I'm just saying that we should also be more liberal in downvoting things we think are bad.

Slereah

Well yes but what I said :p

It's not overly that good an investment of reputation points

ACuriousMind

14:56

If you think the -2 are not a noticable effect on the receiver of the vote, why do you care about the -1 you lose by casting it?

Either both are significant, or none are, but you can't say the -2 are not noticable but the -1 are an "investment"

Slereah

Well because the -2 is compensated by the errand fellow that upvotes it

A negative vote is not compensated, though

ACuriousMind

And, by the way, downvoting questions doesn't cost you reputations.

Slereah

Yes, but answers do

ACuriousMind

I'm more concerned with votes on questions, actually.

Slereah

Bad questions are usually pretty swiftly dealt with, though

Because bad questions tend to run afoul of the rules

ACuriousMind

14:58

I don't mean homework, or other closeable things

I mean questions that are, well, stupid, but on-topic.

Slereah

Quite less common, though

At the very least, they tend to be duplicates

There are only so many stupid questions

AccidentalFourierTransform

wow, the other day I got insulted in the comment section of a post because OP thought I downvoted them, and now Im being frowned upon because of not downvoting

I dont know, its true that some post do deserve downvotes, but I general I think that questions are posted by people who truly want to learn, and even if the question doesn't make much sense a downvote is not the way to go

I dont remember who said that "to ask a good question you must already know half the answer" or something like that

ACuriousMind

@AccidentalFourierTransform You downvote the question, not the user or their intent. If a question doesn't make much sense a downvote is exactly the way to go, after all, the tooltip says: "This question does not show any research effort; it is unclear or not useful"

Treating votes as the judgement of users defeats the purpose of voting, which is supposed to relate to the content.

Danu

By the way, when did you start regularly coming by, @JohnRennie? :)

ACuriousMind

@Danu Since he was made a chat room owner, I guess :P

Danu

15:07

Which was when?

ACuriousMind

A week ago. But I guess barrycarter also dragged him here to talk about relativity beforehand ;)

AccidentalFourierTransform

@ACuriousMind I get what you say, but "if the question does not show any research effort; it is unclear or not useful" I'd rather vote to close it as such

Danu

But don't you think that makes it bad content?

AccidentalFourierTransform

yes, so what? bad content gets deleted from SE anyway...

Danu

No, it doesn't always. Most closed questions don't get deleted---or at least a significant fraction does not.

AccidentalFourierTransform

15:12

199

A: How does deleting work? What can cause a post to be deleted, and what does that actually mean? What are the criteria for deletion?

How can a post be deleted? By a user: You can typically delete your own posts at will; for exceptions, see When can’t I delete my own post? below. To delete a post, just use the delete link below it. Moderators can delete any post instantly. Users with reputation ≥ 2k (more precisely, the edit...

ACuriousMind

@AccidentalFourierTransform Well, I think a close vote is entirely separate from a downvote, the former is about whether the question is on-topic, the latter about whether the question is good. There are very good off-topic questions and very bad on-topic questions, and I have actually at times voted to leave open and downvoted, because I believed the question was on-topic even if it was silly.

AccidentalFourierTransform

the thing is, IMO there are not bad on-topic questions

if the question is bad, its fairly easy to come up with a reason to close it

Danu

@AccidentalFourierTransform Note that upvoted, but closed questions don't get deleted

Since there are many "noise upvotes" (on terrible questions), this causes a bunch of bad stuff to remain on the site.

ACuriousMind

@AccidentalFourierTransform Okay, I guess I just have higher expectations regarding what constitutes a good question

Secret

No offence, @Acuriousmind, but after observing the chatroom for some time and also reading questions in the main site (thanks to the RSS), I found that your often found questions unclear but there are often a lot of answerers get what the users are asking and then result in an accepted answer.

This is kinda the opposite of my scenario where most people have no idea what I am asking

I am kinda wondering, how can we help users to clarify their questions rather than downvote them?

@AccidentalFourierTransform I agreee with you, if a question is something from a lack of googling or other effo…

Secret

15:19

As for downvoting and closing, if I were more confident in my knowledge AND not make so many silly mistakes in my thinking, I know I have the tedency to downvote and vote to close questions

But since I still don't, I am reluctant to close or downvote questions for fearing in making a misjudgement (because votes stick after the time to revert it expires

ACuriousMind

You cannot vote to close questions, and your total number of votes cast is 6.

AccidentalFourierTransform

@Danu I agree on the noise upvotes, but Im more concerned about upvoting good q/a than downvoting bad ones

ACuriousMind

@AccidentalFourierTransform Well, do you hit the 40 votes/day threshold usually? If not, you could easily both upvote quality stuff and downvote the garbage.

AccidentalFourierTransform

after all, a bad q/a is just boring or stupid, but OP didn't do anything bad per se

Secret

I am saying in the future where I am more competent in the physics understanding, but otherwise what you just said

Danu

15:22

@AccidentalFourierTransform Wasting everybody's time, at least.

Secret

When I deal with bad question, if it still fall within mainstream physics, I will often comment to ask the OP to clarify on the issue, in order to encourage them to make their point clear

One reason of doing this instead of downvote is that when I read a question, it will sometimes become my question as whatever that at first seems confusing thing is arose my curiosity to learn more about it

I only do the commenting mentioend above for questions that are marked unclear, because these can still be saved by either make them clear, or addressing the misconception

I think that is more important

AccidentalFourierTransform

i.imgur.com/4EdkQMf.png?3

@ACuriousMind ive hit the 40 limit very few times actually

Secret

So the idea is, if the OP can make it clear and someone else answered their question, they also causd me to learn.

And I do remeber the goal of SE is to provide a platform of Q and A that can address future visitors

ACuriousMind

Really, @Secret, why do you insist on using explicit line breaks after multiple people have said it makes your posts harder to read in chat?

AccidentalFourierTransform

but Im an active voter (im in the top 50 voters this year, which is not bad keeping in mind that I only upvote :-P)

Secret

15:28

Ok sorry, habits die hard...

I will try to be more aware of it

ACuriousMind

@AccidentalFourierTransform Yeah, I usually don't hit it either.

@AccidentalFourierTransform Most people mostly upvote, it's anomalous to have an upvote:downvote ratio smaller than 10:1

AccidentalFourierTransform

@ACuriousMind I find it funny how you've lost almost as much reputation downvoting as Ive earned this year

you have downvoted answers 3,159 times

ACuriousMind

No, I actually think most of my upvotes are on answers, so it's more like 2000, I think

Secret

I usually upvote on answers more than qustions (my 6 votes are all on answers, right?)

AccidentalFourierTransform

I meant that those 3,159 downvotes cost you that much reputation

ACuriousMind

15:33

@AccidentalFourierTransform You're reading the tab wrong - I have cast 1796 upvotes and 8267 downvotes, and of all these votes 6904 are on questions and 3159 are on answers

It doesn't tell you how much of the downvotes were on answers

So, I have lost somewhere between 1300 and 3100 rep by downvoting

Although I'm not sure if this includes votes on posts that were later deleted

Then I've lost a lot less, since that rep is refunded when the answer is deleted

AccidentalFourierTransform

yea I get it

Danu

16:04

Exceptional Lie groups are the worst

user147690

16:33

Which Lie group corresponds to $E_8$?

DanielSank

Anyone know how to reply to older messages on the mobile interface?

user147690

@DanielSank Do you know the message number?

user147690

Can you get the permalink?

DanielSank

Hmm, perhaps.

user147690

If you can get the permalink, then just do :12123123 and your message

DanielSank

16:40

I cannot. The mobile interface doesn't allow me to reply to it see the message number of posts in my inbox.

user147690

Ok, well the permalink has the message number, but I probably misunderstood you. If you can't directly reply, and can't get the permalink, you can just ask us to give it to you. What is the message?

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