The h Bar

Balarka Sen

00:00

Cool chap.

ACuriousMind

@0celo7 What's your current answer to whether you're a nerd or not?

0celo7

@ACuriousMind Never. I tell Rebecca I am to make her feel better about herself being one.

But I am of course not one.

ACuriousMind

Your self-denial is adorable :)

0celo7

I can't even understand homology

how could I be a nerd

@ACuriousMind Name one nerdy thing I do

I do not play video games

I do not watch sci fi

I have never read a comic

Manga does not count

ACuriousMind

@0celo7 ...I've got only mean responses to that :/

@0celo7 You don't?

Balarka Sen

00:04

lol

0celo7

@ACuriousMind I tried to play one on Friday and was quickly bored.

I read some Milnor and got depressed and so did...something

Not sure what happened

Balarka Sen

Video games are not exciting.

ACuriousMind

@0celo7 Read GR and math books for fun. That's pretty nerdy

0celo7

I haven't read a GR book in...like months

and I don't read math books for fun

Balarka Sen

Milnor does not count as a math book, of course. He's using it to learn how to cook.

0celo7

00:06

@BalarkaSen Technically I'm taking a class

Although I won't do it again...I thought there would be more interaction with the prof

ACuriousMind

@BalarkaSen Knowledge of the critical points of the pan is important, I agree

Balarka Sen

"Milnor's 10 advices on how to cook a desert"

ACuriousMind

@0celo7 Why exactly did you read, say, Arnold?

0celo7

@ACuriousMind Well...the same prof told me to.

I'm actually quite upset at him right now

He's made me feel like a complete idiot

ACuriousMind

Perhaps he's a meanie and that was the goal

Balarka Sen

00:09

cook him a desert following Milnor's advise and mix some potassium cyanide with it

0celo7

@ACuriousMind No, he's always really nice and helpful when I ask him for stuff

He writes proofs and sends them to me when I have questions

He proved something that Sam sent to Ellis

ACuriousMind

@BalarkaSen Unless you think the advisor likes bags of sand that should be a 'dessert', I think ;)

0celo7

ss = strawberry shortcake

@ACuriousMind In other news, I had to proof-read my other prof's journal review. I apparently spot his Germanisms the best out of anyone in our group.

Also I'm the most junior member, that might have something to do with it

ACuriousMind

Well, you have the advantage that you can spot he's translating literally instead of just expressing himself awkwardly

@0celo7 What?

0celo7

@ACuriousMind the worst thing in there was "it has not yet the value the authors insist"

When he thinks about it, his English is pretty good

ACuriousMind

00:13

Is that a mnemonic for the double s in dessert?

0celo7

Emails on the fly are usually terrible though

Balarka Sen

@ACuriousMind it's a reference to hitler

0celo7

hitler_count ++

ACuriousMind

@0celo7 lol, was about to write the same

0celo7

@ACuriousMind Yup.

@ACuriousMind But that was a typical German construction

Balarka Sen

00:15

if anyone has a problem with hitler, i can call him the h-dawg

"hitler is my homeboy"

0celo7

It's hard not to troll when Hitler comes around

But I got a week for that once

A week and 6 hours or something

ACuriousMind

@BalarkaSen uhhhhhh

I'm not sure what you want to tell us with that

0celo7

@ACuriousMind Be proud of your heritage

Bernard Meurer

@ACuriousMind We should beat them in hitler-count

0celo7

hey

Balarka Sen

00:18

@ACuriousMind Nothing, really.

0celo7

@BalarkaSen Ok, I'll suggest either Bott & Tu or Cheeger & Ebin.

Been wanting to read the former for a while.

Global Riemannian geometry.

Balarka Sen

Whatever that makes you happy.

0celo7

I think neither is unreasonable.

Unlike Milnor.

ACuriousMind

@0celo7 Be Deutsch, you mean?

@BernardMeurer I think that's rather high on the list of "bad life goals".

Bernard Meurer

@ACuriousMind You're talking to me remember? The guy whose life goals include running linux on tubers

Balarka Sen

00:23

@ACuriousMind The hell.

ACuriousMind

@BernardMeurer I, for one, welcome our new potato overlords

Bernard Meurer

@ACuriousMind I just hope they don't have Oedipus complex

ACuriousMind

@BernardMeurer uhhhhhh

I might need to bleach my mind now

Bernard Meurer

@ACuriousMind :D

I have that effect on people sometimes

0celo7

@ACuriousMind slightly strange question

Bernard Meurer

00:28

Potato-cyborg AI overlord interracial porn does sound cool

0celo7

Does American black culture seem strange to Germans or is it pretty mainstream there?

user54412

In other news, apparently being a pokemon hotspot is now a selling point in apartment listings.

0celo7

I grew up in a "kaff" according to everyone, there was no pop culture there

Balarka Sen

@ChrisWhite is that from clickhole

Bernard Meurer

@ChrisWhite Heya! Yep, I saw that, I'm actually checking that for my recent move :)

0celo7

00:29

@ChrisWhite that's not news

user54412

@BalarkaSen No I'm actually searching for an apartment right now.

ACuriousMind

@0celo7 I don't think Germans have a notion of "American black culture". I certainly couldn't really tell you what exactly it entails

@ChrisWhite lol

I'm surprised, but I really shouldn't be

0celo7

@ACuriousMind rap culture, gangster culture

Bernard Meurer

@ACuriousMind What are your thoughts on Brazilian african religious culture in the 21st century?

user54412

Just imagine what would be asked for an ACM AMA

Balarka Sen

00:31

lol

0celo7

All he knows are Witten facts

Bernard Meurer

@ChrisWhite Lel, that'd be awesome though

ACuriousMind

@BernardMeurer Thought: "Thank the gods that I'm not in school anymore and don't have to write essays on stuff I have no clue about anymore"

Bernard Meurer

@ACuriousMind Please do an AMA

@ACuriousMind Ha, that does sound like a school essay topic doesn't it?

0celo7

He's not a researcher

Bernard Meurer

00:32

No wonder I microwaved grapes in school

Balarka Sen

you did what?

user54412

that's what kids call it these days

Bernard Meurer

@BalarkaSen I got suspended for microwaving grapes

@ChrisWhite Kinky

Balarka Sen

i do not get paid for microwaving grapes

Bernard Meurer

@BalarkaSen It's pretty cool, they make plasma and it ruins the microwave overtime I found out

Balarka Sen

00:35

How the hell did you get that idea, even?

Bernard Meurer

The school inspectors where very keen on it, thought it was p. cool as well

@BalarkaSen Someone mentioned that it made fire to me once when I was a kid I think

It took me a while to improve the technique, you need a very specific cut to make plasma

0celo7

Microwaving most things makes fire eventually.

Balarka Sen

Microwaving metal does. But grapes?!?

0celo7

Eventually @BalarkaSen

Bernard Meurer

@BalarkaSen Yes, ask my philosophy teacher, he saw it

0celo7

00:37

I think?

Bernard Meurer

Plasma coming out of grapes

is amazing

0celo7

I have not tried it, I admit.

ACuriousMind

My chemistry teacher loved immolating gummi bears in some sort of acetone solution, iirc

0celo7

@ACuriousMind I love dissolving random plastic things in it at work

ACuriousMind

They burn blazing white for about a minute

0celo7

00:37

When I'm eating for a measurement, etc. I melt stuff

Also throwing things in liquid nitrogen

Balarka Sen

Disclaimer: do not try this at home!

Bernard Meurer

Any volunteers?

I'll be gentle, I promise

0celo7

i volunteer Michelle

Bernard Meurer

@0celo7 She's too good to me for that

ACuriousMind

@BernardMeurer Oh, that's a relief, you will gently cut someone up and turn them into plasma

Then it's fine

Bernard Meurer

00:39

@ACuriousMind I'm glad you're on the side of science in this one :)

ACuriousMind

Also, what does it tell us about this chat that that got 2 stars in like seconds? :P

0celo7

@ACuriousMind just some like BDSM

*light

Bernard Meurer

@0celo7 I bet ACM is into hardcore BDSM

0celo7

We're savage nerds (except for me)

@BernardMeurer oh you know it

Balarka Sen

Sadists.

0celo7

00:40

I can't tell if he's sub or Dom

user54412

speaking of which...

Bernard Meurer

@BalarkaSen I'm not sad?

0celo7

Probably too skinny to be a convincing Dom

user54412

I see an add for an apartment that includes "a happy unit with great vibrations" -- I honestly don't know if this is serious, innuendo, or lost in translation

ACuriousMind

@BernardMeurer Why does everyone think that?!

Bernard Meurer

00:41

@ACuriousMind You have the looks of a kinky man

Balarka Sen

@ChrisWhite lolwut

ACuriousMind

@ChrisWhite It means it's right next to a train track that shakes the building regularly

Bernard Meurer

@ChrisWhite Wear a condom please

0celo7

@ACuriousMind well then tell us about your preferences

Clear up the confusion

ACuriousMind

@0celo7 oO

0celo7

00:44

@ACuriousMind btw Mordin was your best avatar

Balarka Sen

Weird conversation, not sure why I am not leaving.

ACuriousMind

@BalarkaSen You're probably turned on by it :P

0celo7

Jeez

ACuriousMind

@0celo7 I am inclined to agree, with the possible exception of Morte

Bernard Meurer

@ACuriousMind That's why everyone thinks that you're kinky

Balarka Sen

00:46

Officially weirded out now.

0celo7

For the record: I am not currently aroused

2

ACuriousMind

@BernardMeurer Touché

Bernard Meurer

@0celo7 I'll tell Reb you're being aroused by German man on the internet

0celo7

@BernardMeurer we're each allowed one person to cheat with

Bernard Meurer

@0celo7 I doubt that

Balarka Sen

00:47

Persons, not trolls/orcs.

Bernard Meurer

If her definition of person is broad enough that could be quite a few individuals

0celo7

Oh shot ACM is a troll

Sorry buddy

Bernard Meurer

@0celo7 She must believe that "We are all one in Christ", so there you have it

0celo7

I guess it defaults to Scarlett Johannson in that case

ACuriousMind

I'm an orc, dammit!

Bernard Meurer

00:48

I should be a lawyer

0celo7

@BernardMeurer contrary to your belief, she is not a Christian fundamentalist

@ACuriousMind what's the difference

Bernard Meurer

@0celo7 That's what she wants you to think

0celo7

@BernardMeurer how do I find out for sure

Burn a bible in front of her?

Bernard Meurer

@0celo7 Get a satanist symbol and touch her with it, check for skin burns

HDE 226868

01:13

Has anyone here ever read Eddington's The Internal Constitution of The Stars?

0celo7

has @ACuriousMind gone to sleep

@BernardMeurer will do

Bernard Meurer

@HDE226868 Yes, spoiler; they're made of pudding

HDE 226868

@BernardMeurer Picks up spoon and whipped cream and journeys to the center of the Sun

Wait, I forgot a bowl!

Picks up nearby black hole

vzn

01:32

in theory salon, 1 min ago, by vzn

The Complexity of Quantum States and Transformations: From Quantum Money to Black Holes / aaronson

0celo7

02:11

@ACuriousMind What are the chances of a person being decapitated while hung?

Bernard Meurer

@0celo7 I guess the fatter they are the more likely it is

puts more pressure on the neck

lucas

02:42

@NeuroFuzzy, @HDE226868 meta.stackexchange.com/questions/281332/…

user54412

03:36

@HDE226868 No, but I highly recommend Schwarzschild's Structure and Evolution of the Stars if you're into that sort of thing.

user54412

(Note there are only about half a dozen textbooks ever written that I highly recommend.)

0celo7

03:48

@ChrisWhite what are they?

user54412

Hmm, I'm actually not sure I can come up with that many.

user54412

Probably Carroll and Dummit & Foote are on the list.

0celo7

04:17

@ChrisWhite wow no HE?

Lee?

Bernard Meurer

04:41

@ChrisWhite Do you know good learning material for ASM?

John Rennie

06:19

@BernardMeurer It's not a plasma, just a flame

Bernard Meurer

@JohnRennie Thx for ruining my life

John Rennie

@0celo7 I'm sure I answered a question about this, but I can't find it now. Anyhow it runs out the force needed to reliably break the hangee's neck is only slightly less than the force needed to pull their head off. Decapitation used to be quite a common side effect of execution by hanging.

@BernardMeurer Physics: ruining lives for two millenia

Bernard Meurer

@JohnRennie Because of this I am now a fundamentalist creationist

ALL SCIENCE IS SIN

see what you've done to me?

John Rennie

When Saddam Hussein was executed by hanging they got the drop height wrong and he was decapitated.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Did you watch it on youtube?

John Rennie

06:23

@BernardMeurer It's still an awesome experiment. It used to entertain my nephews and nieces for hours. I've never known it to damage a microwave - mine still works despite immolating many, many grapes.

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ no

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

It's not that good.

Bernard Meurer

@JohnRennie Yeah, but the thing is when you bypass power limitations to manually control microwaving power and make extra fire

John Rennie

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ Yes it is!!

@BernardMeurer and I imagine installing Linux on the microwave doesn't help :-)

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

I wonder it the military in turkey is going to execute the revolutionaries?

Bernard Meurer

@JohnRennie I failed to do that, it's a bit scar in my career

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

06:35

*if

When do you leave for Lisbon? @BernardMeurer

Bernard Meurer

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ God only knows, sometime in the next 2 months

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

So you're not packed :P

Bernard Meurer

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ Nope, why?

And I don't really own anything to bring with me apart from some books

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Gotta get ready for the big league.

Bernard Meurer

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ Me?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

06:42

yup

Bernard Meurer

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ What do you mean? Which league?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

University is the "Big league"

Bernard Meurer

Ah, yeah, I'm not excited for that

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Then why go?

Bernard Meurer

Because
1. I need a degree
2. Going somewhere > going nowhere

I'm just sad I'm not going to a school I wanted to go to

I feel like maybe I'll be a good CEng student, and I really wanted to go to a good school

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

06:50

That's understandable.

Bernard Meurer

And also, I don't know anyone in Europe in my area

Physics Meta

0

Q: About close votes

The process of closure of this question of mine has been started. As you can see in the figure below, the number of close votes is 3. (the picture has been taken at 18, July, 2016, 06:00 UTC) But there are just two close votes in the review page of that question. (the picture has been taken at ...

bug

Bernard Meurer

not even remotely

That makes me insecure as hell

I really wanted to go to US/Canada

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

You'll be able to transfer...

Bernard Meurer

I know, I know; I just haven't gotten over the fact of how badly I failed at college apps

It's kind of a punch in the gut, I felt like I was good at my stuff and now I don't anymore; it's weird

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

06:54

Now you can prove those college app people wrong!

lucas

07:18

@DavidZ Congratulation! You showed me your power! But I don't know why do I not fear?!!!

lucas

07:44

Ron Maimon, New York City

1 6 115 235

quantum-mechanics quantum-field-theory general-relativity particle-physics string-theory electromagnetism black-holes

cheers!

DanielSank

this chat room used to lay out well on my mobile. Now it's all borked. Do you guys use a web browser or the app on mobile?

@BernardMeurer you are good at stuff

John Rennie

08:06

@lucas the Physics SE is a great place to learn about physics, and actually it's a great place to chat to other ~~nerds~~ physicists. But you have to approach it in the right spirit. Right from the outset you have seemed determined not to have a good time here.

I guess it's up to you, but it seems a shame to ignore a great way to have fun.

@BernardMeurer not that I boast about it, but I didn't get my college of first choice. In fact I had to take an unexpected year out and reapply the following year. However I ended up having a really good time, and stayed on to do a PhD, which was an even better time!

lucas

@JohnRennie Thank you John! I miss you. I am so happy that you are talking with me. May you please guide me why am I wrong?

John Rennie

If you go to uni determined to have a great time then you will. I guarantee it :-)

lucas

@JohnRennie I was at uni for 4 years.

John Rennie

@lucas you've got yourself into the position where you thinks the mods are out to get you. They aren't. They are just trying to keep this site running as it was designed to.

If your questions and answers are being poorly received then you need to look at why this is rather than assuming it's down to hostile moderation.

lucas

@JohnRennie I agree, but some events make doubt for me. I think you know what are those events.

I don't talk about down votes.

John Rennie

08:12

Why did you link Ron Maimon's profile? Do you think he is another example of unfair treatment?

lucas

@JohnRennie No, David Z closed my question to show me he is powerful. And I wanted to say him his power is nothing in my opinion.

John Rennie

@lucas David Z closed my question to show me he is powerful - if that's what you believe you might as well give up now.

lucas

@JohnRennie I don't want to continue if they respect to me. Believe me.

They usually insult me, close my posts, delete my posts, etc.

And now, I am the bad person.

Because their actions are hidden.

If you had access, you could easily know that their actions about me aren't usual.

They want (force) me to go. But I won't go.

@JohnRennie Are you with me yet?

John Rennie

@lucas I think you are entirely mistaken. Why you think you're being persecuted I don't know, maybe it's the language problem. Whatever the case, you have completely misinterpreted the actions of the moderators.

lucas

@JohnRennie Maybe. I don't want to waste your time. But may you please (fairly) say me that has he insulted me in his answer or not? And may you please say to me is my question very bad? physics.stackexchange.com/questions/267302/…

Believe me, I won't stretch the discussion. I promise!

John Rennie

08:34

@lucas I read and reread that question of yours several times, and I couldn't work out what you are asking. I would also have voted to close as unclear if the question hadn't been closed before I got to it.

lucas

@JohnRennie Thank you! What about the first question? (insult)

John Rennie

Who, Motl?

lucas

Yes

John Rennie

Motl is an overgrown schoolboy and I suspect he says insulting things without even realising he is causing offence. We put up with him because he has also provided some of the best answers on the site - far better than mine.

Motl would no doubt argue that what he said is true, and I have some sympathy for that point of view.

Your answer got closed because it was too confused for us to provide a meaningful answer. The difference between us and Motl is that we didn't say so to your face.

lucas

@JohnRennie Thank you very much John! You made me happy today after I had some terrible days. I really miss you since you decided to not talk with me. May I ask if you will talk with me in the future or not?

John Rennie

08:43

In the past I have found you don't listen to what the other person is saying - you consider only your own point of view. Maybe this is just the language problem, but that's the impression you have left me with. This makes discussing physics with you not much fun.

lucas

@JohnRennie If I promise that won't discuss about physics, will you talk with me?

John Rennie

I have to leave for about an hour to go shopping. If I don't reply in the next hour it doesn't mean I'm ignoring you, just that I'm out shopping.

lucas

Have a good shop!

The Quantum Physicist

11:25

Hey guys, I would like to discuss density matrix evolution. I'm having trouble understanding the equivalence between the evolution of a density matrix in the eigensystem of the hamiltonian compared with the evolution of a wave-function in the eigensystem of the hamiltonian

The evolution of a wave-function will be very simple if it's in the eigenstate of the hamiltonian, because each state's evolution will be independent of time

Now how does this simplicity show up when dealing with density matrices? Are we supposed to have only a diagonal matrix? That doesn't sound right.

Would someone please explain this to me? I'd really appreciate it

ACuriousMind

@TheQuantumPhysicist "Diagonal matrix" would be a basis-dependent statement. But look at the definition of the density matrix associated to a state $\lvert \psi\rangle$: $\rho = \lvert \psi\rangle\langle \psi \rvert$. Now, if $\psi$ is stationary, then it evolves with just a phase $\exp(-\mathrm{i}Et)$, and its bra with the conjugate phase, so the density matrix...doesn't evolve at all. It doesn't get simpler than that!

The Quantum Physicist

@ACuriousMind I'm interested in the nature of mixing the states and when they don't mix

that's my dilemma, because I'm trying to simply computation

ACuriousMind

I'm not sure what you mean

You asked how the density matrix of an eigenstate evolved, I told you

Or did I misunderstand your question?

The Quantum Physicist

@ACuriousMind Not entirely. You got part of it

The generator of my question is the following issue: What are the cases that guarantee that all my states in my density matrix will evolve independently, and what does that imply

Let me try to explain a little more, if you don't mind

Imagine I have some Hamiltonian H that is time independent. Now I want to evolve some initial density matrix, and on the other hand I want to also evolve some wave-function

What I understand is that evolving this wave-function is the easiest (computationally) when the wave function is in the basis of the Hamiltonian. This is because each matrix component of the wave function (which is a column matrix) will evolve independently of the others

Is what I'm saying correct until now?

ACuriousMind

Yes, I have no objections

The Quantum Physicist

11:39

So what I'm trying to understand is: What are the similarities between this simplified version of wave-function evolution, and density matrix evolution

In other words: How simple will density matrix evolution become when it's in the Hamiltonian basis

ACuriousMind

@TheQuantumPhysicist Let's call the Hamiltonian eigenbasis $\lvert \psi_n\rangle$ with energies $E_i$. Then the matrix in that basis is $\rho = \sum_{i,j} \rho_{ij}\lvert \psi_i\rangle\langle \psi_j\rvert$. Apply how each eigenstate evolves and you get that each matrix element evolves with a phase, i.e. as independently as the coefficients of a wavefunction in the Hamiltonian basis.

The Quantum Physicist

$\rho_{ij}$ is an arbitrary initial density matrix, right?

ACuriousMind

The $\rho_{ij}$ are the coefficients of the initial density matrix $\rho$ in the Hamiltonian eigenbasis

The Quantum Physicist

So you're saying that I have to evolve with $e^{\left(\omega_{i}-\omega_{j}\right)t$

which means that each matrix component will evolve independently

ACuriousMind

Yes

The Quantum Physicist

11:46

But this can still (computationally) be simplified further, right? Because density matrix is Hermitian and $e^{\left(\omega_{i}-\omega_{j}\right)t}$'s diagonal is 1

So I can ignore half of the matrix + consider the diagonals to be constant

@ACuriousMind I hope I'm getting this right!

ACuriousMind

@TheQuantumPhysicist Yes, that's also correct.

Are you trying to do numerical computations?

The Quantum Physicist

@ACuriousMind Yes

I have some recipe from someone who left the group and I'm trying to understand what he did

ACuriousMind

In that case, there's a large body of literature and well-tested methods on how to implement the appropriate numerical schemes

The Quantum Physicist

He uses element-wise matrix multiplication which simplifies time-evolution A LOT!

ACuriousMind

Trying to invent your own scheme will almost certainly be inferior to using the tested methods

The Quantum Physicist

11:50

Would you provide some of these references?

@ACuriousMind Well I'm not inventing... I'm just following up with what he did

ACuriousMind

@TheQuantumPhysicist Oh, okay, in that case, carry on

The Quantum Physicist

I have a code that works, and I translated it to C/C++, and now I want to understand it :P

@ACuriousMind Would you provide some good reference for this problem?

ACuriousMind

@TheQuantumPhysicist Well, I know those references exist from talking with people who do these numerical schemes here, but I am not actually qualified to recommend any.

The Quantum Physicist

@ACuriousMind Oh, I see! Thanks for the help :)

I'll think about it further and see where I arrive at :)

Alex

@ACuriousMind Somewhat possibly silly QM question...In the eigenvalue equation of the position operator we have $$\hat{R}|\vec{r} \rangle = \vec{r}|\vec{r} \rangle$$, on the right hand side we have a position vector times a vector from Hilbert space. How is this vector multiplication allowed?

ACuriousMind

12:01

@Alex Ah, that's not a vector multiplication. You're supposed to read that as $\begin{pmatrix} \hat{R}_1\lvert \vec r \rangle \\ \hat{R}_2 \lvert \vec r \rangle\\ \hat{R}_3\lvert \vec r \rangle\end{pmatrix} = \begin{pmatrix} r_1\lvert \vec r \rangle \\ r_2\lvert \vec r \rangle \\ r_3 \lvert \vec r\rangle \end{pmatrix}$ or more simply as "code" for $\hat{R}_i\lvert \vec r \rangle = r_i\lvert \vec r \rangle\forall i$.

Confused me when I first saw it, too

Alex

@ACuriousMind Oh yeah that does make more sense...should I think of the position eigenvectors as being vectors in some larger generic Hilbert space, since they are not $L^2$?

The Quantum Physicist

Guys do you see Math here? Should I install some plugin to see it? Actually I currently use LyX to read your equations

ACuriousMind

@TheQuantumPhysicist Look in the upper right corner, there's a link to MathJax for chat there

The Quantum Physicist

hmmmmm... I normally install MathJax myself on my websites, and not expect my clients to install it :)

I'll check that. Thanks :)

ACuriousMind

@Alex Yes, but the larger space is not a Hilbert space (for one because it is not self-dual). You actually need a triple of spaces to make sense of this, called a Gel'fand triple or rigged Hilbert space. See, for example, this question

@TheQuantumPhysicist Chat is kind of an afterthought on SE sites, features for it are not very high on the developers' priority list, and there aren't that many sites that would need TeX in chat anyway

Alex

12:12

Kewl, will check it out.

The Quantum Physicist

@ACuriousMind Yeah well. It's not that bad. I installed the extension and I see equations now :)

ACuriousMind

@Alex Be careful - delving into the proper mathematics is interesting, but it will not make understanding what the average physicist does any easier. It might even puzzle you more how the heck they get away with what they do ;)

Emilio Pisanty

0

Q: $V(T)= 0.0000679T^3+0.0085043T^2- 0.0624T+999.87$

sorry for asking this kind of question. do you recongnize this formula? $$V(T) = 0.0000679T^3+0.0085043T^2- 0.0624T+999.87$$ when $V$ is volum of water in $ml$, $T$ is temperature in celsius. this is approximation for volume of 1kg of water with temperatures between 0~30 celsius this formula i...

approximations

↑ ?

Looks fixable, but not quite sure how best to do it.

ACuriousMind

@EmilioPisanty Is the question being asked "How is this approximation for the temperature-dependence of the volume of water derived?"?

Then one should cut out all the fluff and trim it down to that

Emilio Pisanty

@ACuriousMind Yeah, that's what I get from it

btw, if there are any SQL / SEDE wizards around

0

Q: Can I query the SEDE for what fraction of close reviews are initiated by flags?

I would like to know what fraction of the recent close-vote review tasks were initiated by a flag cast by a user under 3k reputation (as opposed to tasks assigned to the queue by a close vote by a 3k+ user). Is there enough data in the Data Explorer to get this information? If so, how can this be...

discussion support review vote-to-close data-explorer

0celo7

12:40

Good morning

@JohnRennie In the show I'm watching, they had to expedite the hanging of a double agent and his head came off in the process.

Danu

@ACuriousMind :D :D

It might evoke a certain feeling of disgust, at times ;)

user116211

13:21

Schiff's QM book is quite weirdo.

user116211

He writes the Uncertainty Principle as $$\Delta p\cdot \Delta x \geq \hbar\;.$$

user116211

But I was acquainted with $$\Delta p\cdot \Delta x\geq \hbar/2\;.$$

user116211

Also, the bandwidth-time interval product he gives is this:

user116211

$$\Delta \nu \cdot \Delta t\geq 1/2\pi\;.$$

user116211

Although I got in Crawford's Waves, this:

user116211

13:28

$$\Delta \nu\cdot \Delta t \geq 1\;.$$

0celo7

So...there are either flies in my room or I'm seeing floaters

neither one is a good prospect

skill patrol

what are floaters

0celo7

signs of a detaching retina, i.e. eminent blindness

every time I try to swat one of the flies they vanish

or maybe I have lupus

or schizophrenia

user116211

@0celo7 what? .... is it hallucination?

0celo7

I don't know

skill patrol

13:33

go see a doctor

0celo7

no money and I don't know if it's an issue

we will see

skill patrol

don't wait till it becomes an issue

user54412

pretty sure all students in the US are on a mandatory health insurance plan

user116211

@0celo7 Are you still seeing them?

user54412

but I wouldn't worry -- you're not doing college right unless you have a hallucination episode due to overworking and undersleeping (in my case) or drugs (in everyone else's case) ;)

skill patrol

13:39

drugs that keep you awake make you hallucinate

@ChrisWhite how's the conference going?

0celo7

@ChrisWhite Correct

However going to the doctor when there is no issue brings great shame

user54412

@skillpatrol you apparently can't keep up with the pace at which my life proceeds :)

skill patrol

oh, you're back :)

0celo7

what conference

user54412

no I'm in Berkeley looking for a cardboard box to live in

0celo7

13:52

oh, did you get your PhD?

skill patrol

happy hunting

HDE 226868

@ChrisWhite I've heard that recommended quite a lot.

skill patrol

22 mins ago, by skill patrol

don't wait till it becomes an issue

yuggib

@ChrisWhite don't they give you one free with your PhD diploma?

0celo7

99% sure it's flies

they're just tiny

@skillpatrol GREAT. SHAME.

You don't know what it's like being Asian

user116211

13:58

@0celo7 Are there something nasty in your room? Maybe that's why the flies came.

0celo7

@MAFIA36790 No, I cleaned up as soon as I first noticed them.

There's maybe just one now.

user116211

Good.

0celo7

opened the window to give them a chance to fly out

there's less now

just one that's driving me insane

user116211

@0celo7 You can use Citronella oil to shoo away those petty creatures.

HDE 226868

Amusing Wikipedia vandalism.

0celo7

13:59

it's a really small one, not like a fat fly

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