How come one has a countable set of eigenfunctions $\phi_n$? (third paragraph)

@schn In the first line of that section, they reference that they're talking about un-bound particles. Presumably, that means that prior to that they already talked about the case of bound particles

the statement about $\phi_n$ being countable is in reference to the latter case (bound particles, e.g. a particle in an infinite box or in a harmonic potential)

for the free particle, you instead get an uncountable set since every $e^{i k x}$ is an eigenfunction of the free-particle Hamiltonian operator

morning

morning

morning

qphs.fs.quoracdn.net/main-qimg-12ec24a3f6385290a92d2c4f21bdff24

Over 200,000 people had already applied for a one-way trip to colonize Mars in 2022.

\o @Danu

Hey @ACuriousMind you did your master's thesis under Walcher, right?

hi @skillpatrol

@Danu Yes, why?

You thinking of applying for this? :P

how did Walcher react to you not doing a PhD in Physics or Maths :^)

Who is Walcher?

@AbhasKumarSinha did you apply?

@skillpatrol yes :)

:-)

:-)

@ACuriousMind A very close friend of mine is applying

My work is not stringy enough to have a chance for a position like that

Too dry :D

If you don't mind maybe I'll ask you a question or two about him later :)

@Danu You think strings are wet? :P

Definitely

Actually, if you're interested you can have a look at the first paper based on my phd thesis.. I finished the (final?) draft this week

There's some references to physics in the intro but nothing after that

besides some of the terminology

"one-loop deformed c-map"

@Danu Sure, though I'm not sure of how much use my dim recollections from years ago are gonna be. Shoot me an email if there's a chance the questions aren't a good fit for public discussion.

@ACuriousMind Haha, sure, though I'm not sure I have your email address

How's life on PSE? I haven't been on SE too much lately

@Danu You say that every time I ask you send me an email :D

@NovaliumCompany Hey!

Sup

@ACuriousMind Indeed.

@NovaliumCompany great buddy

making deepfakes...

I recall having said that before

using Neural Networks :)

@AbhasKumarSinha Amazing! I'm so into AI

You have a discord?

@Danu I think it's going well - and compared to the network at large, we're being very drama-free lately

@NovaliumCompany send link

@NovaliumCompany github too...

I don't get to answer as much as I'd like to, but that's mostly because I don't have the time to write answers right when the questions appear anymore, I think :P

@AbhasKumarSinha Kapton#2704

@NovaliumCompany I believe that dot chat will lead the future of communication :P

@Danu Indeed

@ACuriousMind Heh, yeah... Damn. Trying to track that whole story was quite a time-burn.

@ACuriousMind Ghehe... Now I see why I couldn't find it when I looked for it in my gmail history

@NovaliumCompany @AbhasKumarSinha You've been told about spamming the chat with pointless dots before. Stop it.

a dot is a point :P

@ACuriousMind deleted that ... :)

@ACuriousMind Thanks... I deleted it.

@NovaliumCompany gotcha, this one

@NovaliumCompany github.com/kapton

@AbhasKumarSinha Add me in discord

not me

@ACuriousMind Still must be a lot of work compared to the relaxing bliss of HSM

@NovaliumCompany discord server link? user link..? name channel...?

@AbhasKumarSinha Kapton#2704

@NovaliumCompany ok...............

@AbhasKumarSinha you just signed your death certificate there

@NovaliumCompany by definition of dot chat, no.

@Danu Sure, but after Chris and tpg joined us earlier this year, we have enough shoulders to divide it unto

Someone (ghghg, ACuriousPerson) will probably hunt you down now

@NovaliumCompany lol, let's see...

@ACuriousMind Why did I get kicked? I didn't spam the chat with dots. My space and dot buttons on the keyboard bugged

@ACuriousMind Chris... He wasn't around yet back when I was active, right?

@AbhasKumarSinha Add me in discord, so we can chat about ai and cool stuff

@NovaliumCompany you'll now be hunted down...

@NovaliumCompany ok... Logging in :)

@NovaliumCompany You got kicked for doing what you were explicitly told not to, and now you get kicked for wasting everyone's time with silly excuses.

@ACuriousMind not fair, he didn't spam now... :'(

why the drama?

@NovaliumCompany told you na... >:0

@Danu Mhm, not sure, he's been on the site for ~4 years

@skillpatrol no, nothing. peace...

@ACuriousMind Hmm yeah... Maybe around the time that I started transitioning away from active site participation. Was mostly around in chat over the past years

I noticed :P

:D

@ACuriousMind So was that actually the start of a crappy voting ring I noticed the other day? I noticed now that even the first person posting is deleted instead of just on a 7-day suspension now. I found it funny the first time I noticed anything like that was right after the question point change.

@JMac I'm afraid we don't talk about the specific reasons for the deletion of users, but let's say if you notice similar patterns in the future, you're invited to flag them, too ;)

@ACuriousMind I just hope similar patterns aren't a result of the point change the other day. Hopefully it was just a coincidence I guess.

@JMac There have always been sockpuppeteers and voting rings on the site, and mods always have spent quite a lot of time observing and removing them. It's not much harder to set up a voting ring on answers than it is on questions, so I don't think "increased sockpuppeteering" is something we could blame on the change, as little as I like it

@NovaliumCompany back! :)

@ACuriousMind why u hate me :(

@AbhasKumarSinha discord, add

@NovaliumCompany will add, no worries... :)

@NovaliumCompany what are you doin now?

@AbhasKumarSinha thinking about why ACuriousMind is being bad to me.

@AbhasKumarSinha Jk, programming some stuff

@NovaliumCompany Just don't annoy her...

Wiat.

wait.

@NovaliumCompany I'm too writing NLP based classifier

her?

@NovaliumCompany why that shocked you?

I thought she was a he this whole time.

@ACuriousMind are you still keeping track a little bit of string developments?

@NovaliumCompany whatever, random chat, online... That doesn't matter

@AbhasKumarSinha You are 17 and programming NLP classifiers?

@NovaliumCompany I am a he, though there is nothing in my profile that indicates that so people can be forgiven for thinking otherwise.

@NovaliumCompany what's new in it? Check my github,

@ACuriousMind okay, sorry!!

@AbhasKumarSinha What's ur github?

@ACuriousMind As a moderator, I think you should at least explain to me why I got kicked for 4 minutes.

@NovaliumCompany github.com/abhaskumarsinha

@Danu Not really :|

@AbhasKumarSinha no worries

@ACuriousMind :)

@AbhasKumarSinha I have to go do some things now, I'll be back later, if you need me, discord.

@ACuriousMind I'm really angry at you.

@NovaliumCompany okay, I've some homework too

@NovaliumCompany I already told you - "I wasn't doing what you thought I was doing, my keyboard is just broken" is not a proper response to getting kicked. At least stand by what you do.

@NovaliumCompany coool man... Take life easy

cya pal

@ACuriousMind just don't chat to me anymore

@Danu Well, technically, I still have the relevant arXiv feeds subscribed, but it mostly rots unread in my inbox

Aw, you still receive the hep-th daily updates?

Man, I recently haven't been finding any interesting stuff in there :( Used to much more

yep

Probably reflects my tastes slowly shifting away

Swampland's all the rage now

I think it's interesting that a powerhouse like Vafa decided to switch to much more physicsy physics

Wondering if it's, at least in part, an attempt to re-legitimize stringy branches of research in more physically minded circles

I'm curious if a big split will reveal itself between strings-gone-mathematician and strings-gone-physics people

@Danu It may just be the logical reaction to believing he's right when he said there's probably no deSitter from string theory!

(or more generally SUSY-gauge-theory)

@ACuriousMind I'm sorry if I have been annoying and spamming dots. I understand it's inappropriate. I will not do it again. If I do it, you have my full permission to ban me forever from this chatroom. I really hate you right now, but I choose forgiveness and peace, than hatred. I'm making some drama out of this I know, but in the end, you are not the one getting kicked.

@Danu I think the split has already been there for quite a while (e.g. actual mathematical gauge theory is largely indecipherable for a non-mathy physicist) but everyone just lives with it :P

@NovaliumCompany ignore this user (everywhere)

Let me give an example

There are some people who are physicists, working in ways that are not completely rigorous (though much more rigorous than most physicists), but are working on mostly mathematically motivated questions from a physics POV

The best example in my mind is Andrew Neitzke

Ah, you mean mathematicians in denial ;P

@skillpatrol wut?

So they're on the other side of the split I envision

@ACuriousMind Right. I really do feel, though, that physicists are nowadays being pressured more to choose a side here and either join a math department or go back to more physicsy physics

So either you do something like Gaiotto, Moore, Neitzke, or you do swampland :D

@NovaliumCompany take some time away from the chat room environment to relax :-)

@skillpatrol smart advice, will do :)

:-)

cya pal

@Danu It's possible you're right - something like Witten's particular mashup of math and physics seems less likely today than a few years ago.

@skillpatrol you are acting very creepy....

@ACuriousMind Ya

I like looking at things sociologically

@skillpatrol your 3rd account is missing....

That's the power, my 4G internet is now 68 MB per Sec...

@skillpatrol okay, they are both who can listen my commands.... :O

Witten is a giant.

@skullpetrol wow, what a great thought!

many will stand on his shoulders :P

physics.stackexchange.com/questions/514405/…

@skullpetrol wow, great leader thou, skullpetrol hail forever!

@ACuriousMind Also note that Witten himself has shifted away from this kinda stuff!

I feel like comments like these give the wrong impression about what makes a homework question on topic.

@Danu How dare you imply that science is done by people! ;)

@AaronStevens which?

@Danu He probably just got bored with it :P

The one I linked to

@AaronStevens I didn't see anything :( !!?

@AaronStevens The question is deleted, only 10kers can see it

Oh oops. That's what I get for using my phone and not refreshing

@AaronStevens which phone?

@ACuriousMind Yeah, I know, disgusting. Probably shows that I've already dropped out of the rat race ;-)

I'm currently using Google Pixel 2

@AaronStevens banned in India...

@AbhasKumarSinha why?

@AaronStevens Project SOLi not allowed

Ah ok. Oh well, I enjoy using it :)

@AaronStevens how's it is? I mean does it lags? camera? stuff?

I don't think the Pixel 2 uses soli

@Danu That you even think about anything but how to publish your next paper shows you're not in the rat race :P

It doesn't lag. Has really good camera software. Still has pretty good battery life after having it for about 1.5 years

@ACuriousMind RIP my career

@AaronStevens No idea, then, heard a long ago that it uses SOLi and was not granted the freq access in India because of 5G implementations...

Ah maybe it does. Idk. I'm not super knowledgeable on all of that. I'm not too technologically picky, so I don't do too much research into all of that.

@AaronStevens oh okay, then it's the old one, it doesn't uses SOLi... That one is pretty good...

I did have a fun interaction with a phone sales person recently though. They were comparing specs between two phones, and I asked what some term meant.

They said it's something only science people could understand

I said well I am studying physics so I'll probably get it

And then they started fumbling around

So really what they were meaning was "I have no clue what it means"

@AaronStevens hehehehehe.....

And they were hoping I wasn't going to dig deeper

I guess I don't look like a "science person"

@AaronStevens gud....

@AaronStevens you needed some einstein like hair for that XD

Haha yeah probably

@AaronStevens All science persons must wear lab coats. It is the law!

@AaronStevens I usually buy phones online...

@ACuriousMind I suppose if I was a true science person I wouldn't have been asking the question in the first place

@ACuriousMind Can confirm

My professor gave me my lab coat on the first day of my PhD and I've never taken it off since

lol

I guess it protects you from physics of all kinds, eh? :P

it just bounces off of me! :D

@ACuriousMind Do you also use the number of pens in the lab coat pocket as rank insignia?

@Loong Yes - the fewer pens, the higher your rank, since it indicates you don't need to write anything down because you can do it in your head.

@ACuriousMind LUL

or, alternatively, you don't need to write any papers because your minions are doing it for you

You might want to keep at least a red one.

why is SE so intent in mucking up?

@Loong marking students' work in red is an awful practice and it needs to stop

use green, or blue, or purple, or whatever. there's tons of ways to make annotations stand out that don't pull in the aggressiveness of a red pen.

@EmilioPisanty Does use of the colour red really bother people because of it's aggressiveness?

@JMac I can't speak to other people's reactions

my comments above are obviously (only) my opinion

Honestly that just sounds completely foreign to me, which is why I asked. I personally wouldn't notice any difference between red or any other colour as a designated marking colour. I'm not really opposed to the idea of avoiding it, if red actually does bother people on it's own.

@JMac Different colours have different cultural associations in different cultures. The colour red has a vast trove of associations in Western cultures, and many of them are negative.

to me, it is extremely disingenuous to ignore those associations

> if red actually does bother people on it's own

note that students won't necessarily tell you that it's bothering them or even consciously notice that it does so

I'm actually a bit surprised I've never thought of it before. In my Jr. High math the teacher wasn't allowed to use "trial and error" in favour of "guess and check" due to negative connotations. If they felt that was necessary, I could see switching red out being just as reasonable or more reasonable. I'm not a learning psychologist, so I can only assume they did the switch based off some sort of research.

I don't know what the learning-psychology literature says about the topic

I'm googling it right now and found a phys.org article about it... so it's still 50/50

(I sometimes take a dim view of some of the straits that psychology research has gotten itself into lately, but if there's credible work I'd be interested in reading it)

in any case, I mostly see it as managing the tone of my communications with students, nothing more

It's not really scientific, but thinking about it I can get behind it anyways. I doubt there is really science for red ink use over other colours, besides just how much it stands out (which other colours can do).

hmmmmmmmm

folks

can anybody make sense of the relationship between arxiv.org/abs/1112.3376 and its listed DOI?

the arXiv preprint is a full text, but the Biophys J pdf I get through my university subscription is just a page with a ton of abstracts

wait

> 3323-Pos Board B428

is this a conference poster presentation?

is that listed on the journal landing page?

why the hell would someone list a conference poster abstract as the DOI for a full-text arXiv preprint???

does anyone know where I can find a reference that derives/explains how their obtained these results?

I'm particularly interested in <1/r> and <1/r^2>, as those values are used repeatedly in certain approximations

hm, actually, I think I might have found some things online

@ACuriousMind Relating this: the voting database has the required information to determine a far more real value of the posts, only the SE is not willing/capable/interested to dig it our from the DB. Even the SEDE can identify the people with the highest skill level. You are one of them.

@ACuriousMind If A could answer the question of B, then we can create a potential between them, roughly so: $P(A,B)=\frac{1}{1+e^{-x}}$. Then we could find the smallest energy by simple gradient walking. Yes, I know that physics is not competition, but giving a pro few rep only because few can understand his posts, is clearly unfair.