The h Bar

12:08 AM

@HDE226868 I so wanted one with displays on the same surface you draw on, but those puppies start at US$1000.

That's too steep for me. Especially just to learn if the tool is right for me.

@dmckee I was thinking screen-less, and I was hoping for <$200. It ended up as a question on Hardware Recommendations beta.

FenderLesPaul

man I forgot how dark it gets when the weather gets cooler here

dmckee

Mine is an Intuos Medium, and I paid US$187 plus tax in a store.

0celo7

@dmckee There's an upload image button. Or just use imgur.

FenderLesPaul

either I should grow up and not be scared of the dark or I should not live alone :p

0celo7

12:14 AM

Gain some weight

FenderLesPaul

not sure how that will help

0celo7

People don't fuck with big guys

FenderLesPaul

true

dmckee

Fancy that. It's been there all along and I just edit it out of my visual field because I never use it. I literally had to mask off sections of the screen before I saw it.

Humans are weird.

0celo7

Palm tree physics 101

dmckee

12:17 AM

I've always used a tree and a bike to indicate two frames in relativity. Those are the tablet versions.

I also did a surfer, but he's a little battered.

Right after I bought the tablet the class I would have used i the most for got given to another teacher in a big rescheduling snafu we had this semester.

So I don't have as many examples as I would have expected.

HDE 226868

I couldn't draw those with a mouse and whatever drawing program I would use.

0celo7

@dmckee Impressive

I should get one so I can save all of my proofs and derivations

dmckee

For proofs and stuff like that you don't actually need the pressure sensitivity of a art tablet, and there are some other choices.

Androids and windows tables with styluses.

Microsoft surface and Samsung Notes and things like that.

Not that I'm getting much out of the pressure sensitivity yet, but I convinced myself the brush tool lets me butcher japanese caligraphy much like I do in real life.

0celo7

12:43 AM

I'm not buying a whole tablet

I have an iPad already

FenderLesPaul

1:37 AM

lalala

0celo7

2:41 AM

@FenderLesPaul GR talk tonight

obe

2:52 AM

D:

0celo7

why D:

0celo7

3:06 AM

@obe what do you want a GR talk

i can do a GR talk with you

obe

@0celo7 That would be really cool.

I have a phone now also.

0celo7

I'm actually in the humanities building now

maybe I can steal a whiteboard

do a skype video call

now that would be epic

obe

You should sleep.

0celo7

uh, I don't have class until 9, mom

and even then, that's just LA

obe

I should be asleep. Though I have data now.

0celo7

3:12 AM

data?

wait don't you start class tomorrow

obe

For some reason it begins on monday.

Even though other classes begin tomorrow.

Reminds me, I had to do volunteer work for 3 days.

I'm only on chapter 13.

What order should I finish the rest of the book?

@0celo7 Cellular data.

0celo7

brb getting shooed away

obe

Done being shooed away?

0celo7

yes, in my room now

So are we discussing GR or not

obe

3:39 AM

Dude I have no GR to discuss, carroll ch3 remember?

I think it would be cool to listen to you and FLP discuss.

0celo7

well he's a bum

Stan Shunpike

3:50 AM

Heyo

I never understood how one measures a wave function.

How do you do it?

0celo7

you don't

Stan Shunpike

Ok. The only property I know it has is $\psi^*\psi$ is the probability of finding it at a point at a particular time.

What else characterizes a wave function?

@0celo7 like for instance, if I can't measure $\psi$, why is it more fundamental than the probsbility itself? Like why not just use the probsbility distribution?

NeuroFuzzy

4:12 AM

@StanShunpike well for one you can construct many different matter waves (1 particle schrodinger) with the same psi squared

or rather, the same $\langle x|\psi\rangle\langle \psi|x\rangle$

@0celo7 that would be pretty cool, actually!

Stan Shunpike

@NeuroFuzzy Uh, I hadn't thought of that!

That's a good point

NeuroFuzzy

@StanShunpike On a related note I was actually looking for reviews of this answer physics.stackexchange.com/questions/206269/…

0celo7

@StanShunpike I swear to Master D.J. Trump that we've discussed this before

Stan Shunpike

@0celo7 We have.

Lolol

0celo7

I just started playing Splinter Cell: Double Agent

Stan Shunpike

4:24 AM

What is that?

0celo7

old school stealth games are crazy

no tutorial, I'm sneaking into some base or something

well night y'all

@NeuroFuzzy the issue is that I'm pretty sure using my front-facing laptop cam will show everything backwards

I wonder if I can stream footage from my phone's back cam

something to figure out tomorrow

NeuroFuzzy

4:44 AM

@0celo7 or to mirror it!

night

FenderLesPaul

5:05 AM

@0celo7 oh I thought it was Friday night

can we do it Friday night if you're free?

Slereah

5:39 AM

@dmckee Which one is Alice and which one is Bob

Physics Meta

5:51 AM

0

Q: Why is @_________ deleting his answers citing 'in order to comply to the site policy'?

While I was waiting for answer for my newly posted question, I noticed one question: A confusion regarding an example in The Feynman Lectures; there @user posted an excellent answer; I cherished his answer especially for the amazing pics he used. But there it was written: Answer deleted by __...

discussion

Slereah

6:45 AM

there needs to be more fields using Alice and Bob

Currently it's just QM, relativity and computer science

yuggib

7:29 AM

@StanShunpike The wavefunction is a mathematical convenience, much more than a real physical object. Let's say that due to the mathematical formulation of quantum theories, hilbert spaces emerge naturally (and therefore wavefunctions, that are associated to quantum states).

A state on the other hand encodes all the information of a quantum system about measurements. To operationally "measure"/identify a state is a quite difficult task in my opinion.

In fact, a first problem is the fact that a measurement modifies the state, hence you need to be able to prepare a lot of identical states to test

A second problem is that either you are lucky enough and your state is an eigenvector of some operator with multiplicity one (so in principle measuring many times such observable would help you identify unambiguously the state, for you obtain the same measurement over and over, and such value is associated to a single state)

or you need to test many observables many times to identify it; in principle, you would need to test all the observables (that are usually infinite) an infinite number of times each, so it goes without saying that it is not an easy task.

As far as I know there is people who disputes (in research work, not on forums) the structure of some a priori well-established type of states

for example that the state of light produced by lasing is not a coherent state; but a mixed states with certain properties

Slereah

8:11 AM

I HAVE COME FOR YOU

SHOW ME WHAT YOU GOT

@yuggib Plenty of QM formalisms don't have wavefunctions

Well, maybe not plenty

But at least 1 has no equivalent

Does stochastic QM have a wavefunction?

yuggib

8:25 AM

I know; but everyone of them has the Gel'fand-Neumark-Segal construction; for the observables are always assumed to form a $*$-algebra of (maybe) non-commutative objects. Therefore, even if the theory does not nedd wavefunctions (in the broad sense of Hilbert space and vectors), you can always construct such a representation

David Z

@Slereah not even QM in general, just quantum computation, and then because that's mostly computer science

Then again QM tends not to involve people very much :-P

Slereah

Well, it is also used for mixed states in general

yuggib

it may not be the better/most convenient one, but it is always there. The point is that to not admit wavfunctions you have to radically change the notion of observables

Slereah

Well they are all equivalent to some degree in the end

David Z

@ChrisWhite I couldn't let this go: faculty get more interaction, but grad students are creepier per capita, so... I'd have to go with grad students

Slereah

8:28 AM

It's not that incredible that you can recover one from the other

yuggib

well, keep in mind that even states that are not pure can be represented as Hilbert space vectors in a suitable GNS construction

Well, in principle the meaning of formulating a different theory would be to predict something more than the old theory

if else there is no need for the new one, and becomes just a matter of interpretation

Slereah

Well yes but the old theory predicts everything that happens

So far not much need for a different thing

Can you recover wavefunctions from the quantum logic formalism?

yuggib

I am not so familiar with quantum logic; but indeed you can recover them from quantum set theory

I suspect that quantum logic is different though

not an expert anyways

Slereah

Neither am I

It just seems to be pretty different from most formalism

Basically it redefine basic propositional logic

yuggib

but the scope is to define a new logic inspired by the quantum theory, or the contrary?

Slereah

8:33 AM

first one

yuggib

if you change so radically the point of view, it becomes very tough to recover the usual mathematical results

user54412

@DavidZ haha I'll keep this in mind next time someone asks me to spend time tutoring undergrads

yuggib

that are based on the ZFC theory of first-order logic

Slereah

Apparently quantum logic couldn't do much and to expand it, you have to use quantum filtering

Belavkin equation

In quantum probability, the Belavkin equation, also known as Belavkin-Schrödinger equation, quantum filtering equation, stochastic master equation, is a quantum stochastic differential equation describing the dynamics of a quantum system undergoing observation in continuous time. It was derived and henceforth studied by Viacheslav Belavkin in 1988. Unlike the Schrödinger equation, which describes deterministic evolution of wavefunction of a closed system (without interaction), the Belavkin equation describes stochastic evolution of a random wavefunction of an open quantum system interacting...

Which looks pretty similar to wavefunctions :p

David Z

@ChrisWhite lol

honestly, the undergrads creep on each other way more than anything else

like any college

yuggib

8:36 AM

in quantum set theory you have a ZFC transfer principle, so you can mutuate (to some extent) ZFC assertions to quantum set theory

anyways, occam's razor would suggest that such a radical change is a bit far fetched seen the success of usual quantum theory and ZFC in math

if it is just for computational convenience then it may be ok

but restricted to that domain

Slereah

Well everything is for computational convenience, in the end

yuggib

ahhaha that may be true

long time without JD...I am bored, and I need some divertissement :-D

Slereah

Time has 4 corners

The Dark Side

9:46 AM

Phew. This could go down as the yuck username for the ages:

kiss my armpit, sandwiched in your smelly armpit

1.3k 9 113 284

tikz-pgf pstricks graphics diagrams math-mode pgfplots best-practices

yuggib

10:08 AM

:-D

Slereah

10:41 AM

I kinda don't like the whole explanation of Hawking radiation via split pairs of virtual pairs

It's not that helpful

Slereah

11:18 AM

spikedmath.com/571.html

too accurate

"One day Shizuo Kakutani was teaching a class at Yale. He wrote down a lemma on the blackboard and announced that the proof was obvious. One student timidly raised his hand and said that it wasn't obvious to him. Could Kakutani explain? After several moments' thought, Kakutani realized that he could not himself prove the lemma. He apologized, and said that he

would report back at their next class meeting. After class, Kakutani, went straight to his office. He labored for quite a time and found that he could not prove the pesky lemma. He skipped lunch and went to the library to track down the lemma. After much work, he finally found the original paper. The lemma was stated clearly and succinctly. For the proof, the author had written, 'Exercise for the reader.' The author of this 1941 paper was Kakutani."

:D

Slereah

11:34 AM

"You've earned the "Nice Question" badge (Question score of 10 or more) for "Highest symmetric non-maximally symmetric spacetime"."

yay

0celo7

@FenderLesPaul yeah

but I had time yesterday

John Duffield

12:02 PM

@0celo7 : no the most complicated and technical books on the market aren't popscience. But some of the stuff you believe is popscience.

@Slereah : the "given" explanation for Hawking radiation is pseudoscience nonsense. Virtual particles are field quanta, not real particles that pop into existence like magic. In addition, there are no negative-energy particles. What there is, is near-infinite gravitational time dilation, which Hawking radiation totally ignores.

Slereah

hush duffield

We're talking real science.

Physics Meta

12:23 PM

0

Q: Should there be a way to flag comments

When experienced users make the first comment on a "bad" question, they are often condescending. This is fair enough, if the question is bad. However, this discourages other, less experienced users with less reputation, from attempting to answer the question. Particularly if the question is an in...

discussion comments

0celo7

@JohnDuffield you do know that's the popsci definition of Hawking radiation?

Indeed, Hawking radiation can be done within the framework of AQFT, which does not refer to particles at all.

It seems AQ has declared jihad on ISIS again.

Not very original.

Slereah

So anyway

If photons are for seeing

And phonons are for hearing

Where are the smellons

And the tastons

ACuriousMind

@0celo7 I don't know about Planetscape, but Planescape is very good.

yuggib

12:39 PM

@Slereah:
>We're talking real science.
[...] 10 minutes later:
> If photons are for seeing
> And phonons are for hearing
> Where are the smellons
> And the tastons

strange definition of real science :-O

ACuriousMind

@Slereah You forgot about feelons.

yuggib

@ACuriousMind like the cryon; not to be confused with the crayon

ACuriousMind

lol

0celo7

@ACuriousMind mm. Typo

Slereah

@ACuriousMind Planescape is best

Particles are easy to remember

But then you have the laundry list of pseudo particles

Also fuck mesons and hadrons, way too many of them

Like half of the PDG book is mesons and hadrons

ACuriousMind

12:44 PM

@Slereah Well, uh, that's what it's there for, isn't it?

Slereah

I suppose

But still

I want to know more about electrons

Not about the p48589c meson

That only appeared once in 1963

During a full moon

ACuriousMind

@Slereah The word order is off there :D

Slereah

Shouldn't there be a small number of mesons, really

Aren't most of them just superpositions of basic mesons

0celo7

What

Is the game about particles

Slereah

Wrong conversation

Planescape is the best game

It is about

FINDING YOURSELF

Literally

ACuriousMind

12:49 PM

What can change the nature of a man?

0celo7

A hot enough woman

ACuriousMind

I didn't want an answer to the question, this is the question that appears over and over in the game's story

Slereah

Basically you are an immortal dude

But every time you are killed, you lose some of your memories

John Duffield

@0celo7 : How about if I ask a question about how Hawking radiation really works, and you explain it? You can tell us all how quantum fluctuations are immune from gravitational time dilation, and how the black hole isn't really black. And isn't really a black hole. And all the other stuff you've got hard mathematical evidence for.

Slereah

So you kinda have to reconstruct what your life was

0celo7

12:51 PM

@ACuriousMind what are quantum fluctuations

John Duffield

@ACuriousMind : isn't there some gameboy website where you can ask questions like this?

0celo7

Isn't that your area of expertise

ACuriousMind

@0celo7 I've never seen an explanation of that phrase that wasn't either nonsense or trivial.

0celo7

@JohnDuffield are you ready to finally back up your electron Dirac belt idea

ACuriousMind

The "best" interpretation of the word "quantum fluctutation" I've found is that there is a standard deviation of observables that is not caused by classical (i.e. statistical/thermal) principles.

Slereah

12:53 PM

Basically

0celo7

"Quantum funkiness"

Slereah

Like how quantum fluctuation of the stress energy tensor is <T²> - <T>²

ACuriousMind

But that's a trivial consequence of the non-commutativity of observables/the uncertainty principle, so it isn't really mysterious.

0celo7

So you're telling me the vacuum is not a boiling sea of particles popping in and out of experience

ACuriousMind

@0celo7 I think I've also told you that before, so yes^^

@Slereah Well, oddly, not the times when you are killed during the game (this always irked me) :P

John Duffield

12:56 PM

@0celo7 : Ask the question. Meanwhile it's like I said. We make electrons in pair production out of electromagnetic waves. We can diffract electrons. We describe electrons with the Dirac equation, which is a wave equation. We know that in atomic orbitals electrons "exist as standing waves", and when we annihilate that electron we get an electromagnetic wave again. And I didn't make up Dirac's belt. A guy called Dirac did that.

I didn't make up the wave nature of matter either.

0celo7

@ACuriousMind that was rhetorical

@JohnDuffield asking a question about your pet theory is by definition non mainstream

I'd probably VTC it myself

I know ACM would and he'd enjoy it too

ACuriousMind

@0celo7 Except for your pet's theory, right?

badumm-tiss

0celo7

Ha

John Duffield

@0celo7 : I am. There are no particles popping in and out of existence. That's a lies-to-children non-explanation. Or as Slereah might say, it's popscience crap for kids.

Slereah

@ACuriousMind Depends how badly you are killed, I think

Plus you can die for real during gameplay

Though it is pretty rare

0celo7

1:01 PM

Should I play this game

Slereah

You should

0celo7

Is it not too old

Slereah

I can only remember two occasions where you can die for real

0celo7

Old games are too hard for me

And sometimes too boring

Slereah

If you piss off the Lady of Pain and if you piss off the giant smith guy

I would say it is pretty good

0celo7

1:02 PM

Spoiler alert

Slereah

Well

She is called the "Lady of Pain"

On principle avoid pissing her off

0celo7

For some reason splinter cell double agent is locked at 720p...it's eye cancer

ACuriousMind

@0celo7 It's a different kind of old than Morrowind. The gameplay is not that fun, it's mostly about the story and the world, which is told through giant chunks of unvoiced text.

Slereah

yeah, the fighting system is nothing special

Know what else is a great story but a poor game?

I have no mouth and I must scream

0celo7

@ACuriousMind I think the morrowind gameplay is sleep inducing

Slereah

1:04 PM

Great story, great atmosphere, reallly poor gameplay

How long have you played Morrowind

John Duffield

@0celo7 : re asking a question about your pet theory is by definition non mainstream. None of what I said above is my pet theory. It's all mainstream. No doubt you'll be dismissing Dirac like you dismissed Einstein, and generally trashing this website with your trollery.

0celo7

I stopped playing morrowind because the walking speed is too slow

Slereah

Yeah that's kind of a problem of morrowind

It starts off pretty slow

Early combat is boring

You miss most of your hits

ACuriousMind

@0celo7 For that, I would forgive you to just set your speed to 100 or something

0celo7

@ACuriousMind how many mainstream authors think electrons are photons going around a loop? @Slereah

Slereah

1:05 PM

It does get better after a while, though

ACuriousMind

@0celo7 Exactly 0.

Slereah

I'm not even sure what that means

0celo7

I seem to have missed all the books that mention that

Slereah

I know plenty of weird theories about electrons, but none of those are that

0celo7

@JohnDuffield sorry, it's not mainstream

Slereah

1:06 PM

Very early atomic physics had the idea that electrons were rings around the atom

There was also the whole electron as spacetime defects

0celo7

And I think my trashing is pretty beneficial

Slereah

Electrons as black holes

Electrons as ONLY ONE ELECTRON

Hm, what else was there

What

which one

Only one electron?

1:07 PM

Oh yes

ACuriousMind

@0celo7 A variant of Feynman-Wheeler where it is one electron going back and forth through time :D

Slereah

It never got really made into a real theory, but some wondered if there was only one electron in the universe

0celo7

Huh

John Duffield

@Slereah : electrons aren't black holes. You can diffract electrons. In atomic orbitals electrons exist as standing waves.

Slereah

Sometimes, it emits a photon, and goes back in time as a positron

0celo7

1:07 PM

Yeah @Slereah you know nothin about electron and black holes

Slereah

Well I didn't say the theory panned out

John Duffield

@Slereah : that's Wheeler for you.

Slereah

It was just an idea put forward

Well Einstein did put the idea forward of electrons as wormholes

ACuriousMind

@JohnDuffield No, their position probability distribution is the square of something that might be interpreted as a standing wave.

John Duffield

Wheeler didn't know the difference between curved spacetime and curved space. If he had, he wouldn't have called them geons. He would have called them...

Slereah

1:10 PM

Can we change John Duffield

I think ours broke

John Duffield

@ACuriousMind : that's cargo-cult woo. It's quantum field theory. Not quantum point-particle theory.

Slereah

He is on repeat

ACuriousMind

@JohnDuffield That is literally what you obtain from solving the Dirac or Schrödinger equations.

Slereah

I think the notion of "it's a probability amplitude" is about as old as quantum theory itself

Older than Dirac certainly

ACuriousMind

And that's quantum mechanics. In quantum field theory, you can't have your standing waves or such, because you don't describe electrons or other things as solutions to the Dirac equation there.

Slereah

1:13 PM

Well you can have waves still

But they are

WAVEFUNCTIONALS

ACuriousMind

@Slereah I wouldn't call things that depend on field configurations instead of space or spacetime "waves", really :P

Slereah

Well I wouldn't call something that isn't made of water "waves", but here we are!

John Duffield

Bah, anything you don't know about you think is non-mainstream, and yet you believe hook line and sinker in woo peddled by popscience quacks which flatly contradicts not just Einstein/Maxwell/Dirac/etc, but the patent blatant evidence of electron diffraction etc. What planet are you guys on? Oh, and have you ever seen this movie?

ACuriousMind

@Slereah No waves in oil for you?

Slereah

Oil, do you mean THE SINFUL OOZE OF THE EARTH

ACuriousMind

1:16 PM

@Slereah No, I meant the delicious stuff you get when smashing olives

Slereah

Do not shake your olive oil please

ACuriousMind

But perhaps olive oil also has sinful connotations for you...

John Duffield

FFS. Talk about chatroom trolls. I volunteer to be a moderator.

2

Slereah

Ahahah

ArtOfCode

@JohnDuffield What's up? People are allowed to chat here, and that's what this is.

Slereah

1:26 PM

-1

Q: Can jet fuel melt steel beams?

Common sense suggests that steel beams should not yield under burning jet fuel without presence of other substances that produce very high temperatures when burning, such as thermite. So can jet fuel melt steel beams?

temperature material-science

How timely

0celo7

1:39 PM

I think I was chat banned.

It said "room is read only"

Slereah

were you

0celo7

What did I do?

Slereah

did you deny Einstein and the Evidence

ACuriousMind

@0celo7 This time around, I didn't see anything banworthy.

But there is one removed message from you, I just can't remember what it said

0celo7

This time around?

Are you saying I've been rightfully banned in the past?

I have to seriously disagree with that...I think. Although there might have been that one time where some idiot starred something obscene or something.

ACuriousMind

1:42 PM

@0celo7 Well, in the other cases, I at least knew for what you were banned. This time, I have no clue

0celo7

I blame the astronomer for that one.

ACuriousMind

@0celo7 Not in all cases.

0celo7

This is my third ban.

ACuriousMind

@0celo7 Yeah, I'm thinking of that

0celo7

I can't remember what it was.

I guess it shows how much time on 4chan. I wouldn't even think of flagging something "inappropriate"

Slereah

1:44 PM

Did you talk about the Tits group perhaps

0celo7

Oh ffs it was my lady of pain comment

Who the hell flagged that

ACuriousMind

lol what

Slereah

what did you dooo

0celo7

How the hell was that even flag worthy

I said "I like my ladies to give me a bit of you know what"

I swear to god if I get banned for that again

Slereah

:D

0celo7

1:46 PM

You know what rhymes with train

brain

Grain

Gain

Cellophane

T-pain

How do chat bans work

I can't believe someone actually flagged that

ACuriousMind

1:48 PM

@0celo7 You're banned from chatting.

Slereah

ban @0celo7 to demonstrate

0celo7

@ACuriousMind thanks

Do multiple people have to flag?

ACuriousMind

Ah, how you get them? I think they're either dealt out by hand by a moderator or if flags on your posts are deemed valid (either by a mod or by enough 10k users (2, probably))

0celo7

@ACuriousMind you seriously thought I wanted to know what "chat ban" means

I have plenty of experience

ACuriousMind

Nah, one person flags them, and then all 10k users get a blue thingy where they can look at the flagged post and deem the flag "valid", "invalid" or "not sure"

@0celo7 No, I was just messing with you :D

0celo7

1:50 PM

Did you say valid

ACuriousMind

I didn't even see a flag

0celo7

Who on earth said valid??

ACuriousMind

But I was away from my PC for a while vacuuming, so I probably missed it.

0celo7

That was totally not ban worthy, was it??

ACuriousMind

I'd not have thought so, but we'll never find out what exactly the thought process here was.

0celo7

1:56 PM

@ACuriousMind well as long as you believe in me

Physics Meta

2:18 PM

0

Q: What is the Cleanup badge awarded for?

It is written in the 'Badges' page that the 'Cleanup' badge is awarded for the "first rollback". What does this mean? I could not understand. Can anyone help?