The h Bar

David Z

00:05

@danielunderwood Well anything that can be converted to SVG or a similar vector format is technically doable in TikZ

user1732

do you miss being in china? @DavidZ

:-)

danielunderwood

Yeah I suppose vectorization may not be terrible and that could be converted to tikz, but I would think that would produce code that couldn't really be tweaked manually...not to mention I have a hard time creating just about anything in tikz

David Z

00:22

@user1732 Eh kind of. I don't miss living there but I would like to go back and visit.

@danielunderwood I guess that depends on how much effort is put into doing the conversion. Lines and certain kinds of curves can always be converted into simple drawing commands.

Or alternatively a quick-and-dirty approach would just use \path for everything

danielunderwood

Yeah my thought was to vectorize then use paths. Trying to classify certain shapes would probably be a better approach though. I guess the only real thing to do it try it out and see how it goes

geocalc33

00:54

Hey guys

how do you prove that the segment $x^2+y^2=1$ passing through the unit square is a geodesic?

danielunderwood

01:45

I think you mean a unit sphere?

ntdsc

01:55

I think I made a crab cavity in a cellular automata.

geocalc33

@danielunderwood I'm looking for a metric depending on $s$ such that $x^s+y^s=1$ is a geodesic wrt. the metric

for $x,y \in \Bbb R(0,1) $

Physics Meta

02:57

0

Q: Why do some random-seeming questions have huge numbers of views?

I am sometimes surprised at certain questions that have received huge numbers of views. For example, I just stumbled across this question. I mean it no disrespect - it's a perfectly nice question - but it only has three votes and is quite esoteric and closed as homework-like. I can't imagine that...

discussion

user1732

03:16

2

^@Physics Meta feed

:-)

user 2646

07:55

ICM 2018 highlights: ‘What did you enjoy? What did you learn?

John Rennie

08:56

It's obviously a busy news day in the UK today

user1732

i was once chased by a crow

it kept swooping down on me

i had to hide under a tree until it went away

John Rennie

09:31

Parker Solar Probe launch is delayed ...

Yellow

10:27

man physics is amazing but exhausting

every minute i am on the internet i find dozens of interesting papers to read.

user1732

@Yellow yup

Physics Meta

11:16

0

Q: Acoustics question

I have the following question: If I throw 11 flasks on the ground, is this coherent or incoherent decibel addition? Can you give me a clue? Thank you once already.

discussion

Emilio Pisanty

11:59

Also: from some initial testing on SEDE, this just misses out on the 99th percentile by views, which at about 18,300 views. — Emilio Pisanty 1 min ago

... which then means that my own top viewcount scorer also misses the cut by a hair ¬¬.

but the view distribution is quite surprising

is this a power law?

... with one runaway view-count-er

15

Q: Gauge pressure vs. absolute pressure?

What are the key differences between Gauge pressure and absolute pressure? Are there any other forms of pressure?

pressure

... currently closed

I... don't think I agree with that closure.

Emilio Pisanty

12:27

this is also curious

the very top-viewcount questions

(the top twenty or so rows here)

with a pretty odd clustering effect at the top

anyways

a penny for y'all's thoughts.

Loong

12:39

@EmilioPisanty log-normal distribution?

Emilio Pisanty

@Loong ¯\ _(ツ)_/¯

user2236

12:55

please, no troll dances in the chatroom; it may be flagged as offensive :P

John Reenie

13:21

@EmilioPisanty weird y axis

I do not understand its logic yet

for instance I cannot guess the values below and above the bottom and top axis labels

nevermind, I missed your first plot!

vzn

14:48

lol dailymail.co.uk/news/germany/article-6048269/…

ACuriousMind

@JohnReenie You have been warned for impersonation of another user once before. Even if in this case there is less danger of confusion, please consider choosing a different moniker. Imitation may be the sincerest form of flattery, but impersonation is not.

Yellow

15:06

What is a good textbook to get starded with thermodynamics?

Once I get a good grasp of the basics I want to dive into the thermodynamics of life.

Avnish Kabaj

Youre acquainted with high school level thermo, right?

Gibbs energy whatnot

Abcd

15:31

@ACuriousMind he didnt impersonate anyone today.

ACuriousMind

@Abcd Do you really want to have a discussion about whether calling oneself "John Reenie" is incompetent impersonation, parody, a compliment, a taunt or something else?

Abcd

@ACuriousMind I swear I read that as "John Rennie" (the normal spelling) . And I thought you are warning the high reputation kind user John Rennie of impersonating someone which he didn't. Sorry.

ACuriousMind

Well, that's one vote for "impersonation", then. :P

Lozansky

I'll admit I also thought it was John Rennie at first glance

Yellow

16:19

@AvnishKabaj Correct.

I read some of Boltzmann's books

they are well written and very interesting

Maybe I should just finish the books I currently have. THERE IS SO MUCH TO LEARN

Avnish Kabaj

16:38

¯\_(ツ)_/¯

danielunderwood

"high school level thermo...Gibbs energy"

I wish I had your high school

Although my high school didn't have thermo at all aside from what we learned in chem classes

Avnish Kabaj

@danielunderwood o.O

They don't teach Gibbs energy in the states?

It's used a lot in other chapters

danielunderwood

16:56

Not that I remember, though my chem sequence in high school was a bit screwed up since my teacher wanted to teach orbitals. The closest thing to thermal that I really remember was phase changes. We handled the different energies in college, though I don't really remember them if I'm being honest

Novalium Company

17:11

Hey guys, 2 questions: What happens to wave diffraction when the gap size is smaller than wavelenght? Second question: How does wave diffraction occur around an obsticle/edge when there is no gap size? Is there any requirement for diffraction to occur around object/edge.

John Reenie

@ACuriousMind fine @ACuriousMind , but unfortunately I have to wait 1 month to change my username (which I would be happy to do)

I wish I could change it right now.

Last time some admin changed my username to userxxxxx where xxxx was a number. can this be done again?

Loong

@user54826 done

user54826

thank you!

vzn

lol impersonation? behindthename.com/name/reenie

Emilio Pisanty

17:54

@JohnRennie See, this is why we protect questions.

danielunderwood

If any of you guys happened to study physics education, did you get to look at ways of teaching specific subjects (like the various ways of presenting QM) or more general ways of teaching/learning? Did you get to look at a shallow overview of a bunch of different parts of physics?

user54826

my nickname was changed from John Reenie to something hundreds of other users are using, in order to prevent impersonating to occur. A bit ironic? But funny anyway.

Emilio Pisanty

@user54826 your nickname was changed from something that impersonates another user to something that doesn't impersonate other users in order to prevent impersonation from happening. I do not see the irony.

user54826

nevermind. I'm happy about the result. I would do it next month if possible, but I doubt a 3rd time would please admins

Avnish Kabaj

And that's how I got banned from stackexchange kids....

Emilio Pisanty

18:07

@user54826 In case you need this to be spelled explicitly: impersonation of other users, like you did earlier today, is considered to be abusive in this venue. Performing abusive behaviour repeatedly, after being explicitly told that it is abusive, is the sort of thing that gets people into extended account suspensions. I'd rather recommend that you don't attempt it.

Any >20k'ers around?

1

Q: Tension on a string between two objects on a friction less surface

I just need my work checked here. Please let me know if I am correct. I had this problem in one of my test in which I did not get full credits. I am re-doing this(hopefully correctly this time) just for my own peace of mind and understanding. Problem statement: The force shown of 6.4N pulls ho...

homework-and-exercises newtonian-mechanics forces mass

200,000+ views over three years

most-viewed question at score $\leq$ 2

closed as homework-like and with three poor answers to its credit

Yellow

Do you have any REALLY HARD linear algebra problem sets?

Emilio Pisanty

... so, maybe one to take off the books?

Yellow

I got a nice book with some problems but you can never solve enough problems.

danielunderwood

@EmilioPisanty maybe it's because all of the introductory tension problems?

Emilio Pisanty

@Yellow there were a couple of nice books by Halmos, lemme look

@danielunderwood oh for sure, it's google-bait, that one

but it's not doing the googlers any good, for sure

Yellow

18:10

by the way I quite like the subject. I can imagine how matrices can be used in polarization and thereby quantum mechanics.

Emilio Pisanty

@Yellow amazon.com/Algebra-Problem-Dolciani-Mathematical-Expositions/dp/…

Yellow

i should get a good qm book too

Emilio Pisanty

amazon.com/Hilbert-Space-Problem-Graduate-Mathematics/dp/… more on the real analysis side but might still be useful

danielunderwood

Want to take bets on how many people have copy/pasted the bold numbers in the question into their homework?

Emilio Pisanty

as I recall, they ramp up to some pretty tall heights of difficulty

Yellow

18:11

really appreciate it!

Emilio Pisanty

@Yellow I take offense at the word "lat" =P

Yellow

meant to be "lot"

lemme fix it

ups

deleted it

Lozansky

Lat means lazy in swedish :P

Emilio Pisanty

You can use male pronouns for me if you want. But gender-neutral pronouns are also cool.

@danielunderwood ugh

Yellow

to be honest I dont mind. Dont know why i did that

As far as i know you are just highly advanced bots

Emilio Pisanty

18:14

> This book was written for the active reader. The first part consists of problems, frequently preceded by definitions and motivation, and sometimes followed by corollaries and historical remarks... The second part, a very short one, consists of hints... The third part, the longest, consists of solutions: proofs, answers, or contructions, depending on the nature of the problem....

> This is not an introduction to Hilbert space theory. Some knowledge of that subject is a prerequisite: at the very least, a study of the elements of Hilbert space theory should proceed concurrently with the rea…

ah, yes

Yellow

I plan on not going outside of my house untill the olympiad camp

Emilio Pisanty

I remember now

danielunderwood

Hmmm those books may be interesting. I don't remember any actually difficult problems when I was doing linear algebra. At most there were a number of tedious ones

Emilio Pisanty

that's what made that book so amazing

Secret

Random political topology

Yellow

18:14

i will just sit here and read

Secret

Let fascist free ideologies be open sets. Then fascism is closed by complement
Then anarcho-capitalism is an open set whoose limit points is located within fascism

Yellow

did you know that there is a mathematican version of michel foucault?

danielunderwood

Though not quite as tedious as my numerical analysis class that made us work out matrix decomposition algorithms by hand

Yellow

in appereance-vise

Emilio Pisanty

they're not just problems - they're interesting problems to sink one's teeth into but also coupled with appropriate background and context so you can place the work into the theory

Yellow

18:15

@EmilioPisanty to be honest I just know the verbal definition of hilbert spaces

I probably need something to read than a problem book

Emilio Pisanty

@Yellow you'll come into closer contact soon enough

for now I'd just get the linear algebra one

Yellow

does not look like that

not in my book

the contents do not contain hilbert spaces

or is it inside vector spaces?

Emilio Pisanty

@Yellow the Hilbert Space one is definitely not one to start if you don't already know some rudiments of the theory at the very least

@Yellow what?

Yellow

what seems to be the problem?

Unrelated observation: Yellow springer math books and LaTeX is sooooo beatiful

its unbeliavable

I understand much better when I read LaTeX books

Emilio Pisanty

@Yellow as compared to what?

Yellow

18:21

anything

They are just superior

Emilio Pisanty

@Yellow how sure are you that Springer yellow books are typeset using LaTeX?

there's other systems for mathematical typesetting, you know...

Yellow

nope

they are not

springer books

AND

latex is amazing

i love them both seperately

@EmilioPisanty users.metu.edu.tr/eduard/TEACH/SC/Math260/Math260.html

these are the contents of the book that iam using

danielunderwood

@EmilioPisanty IMPOSSIBLE

Anonymous

@Yellow That doesn't look like a book as such. More like a set of handwritten notes.

Yellow

yes it is

there is no pdf for the book i am using

Anonymous

18:27

@danielunderwood Eh?

Yellow

but those are the contents

Anonymous

Okay

Yellow

not bad eh?

danielunderwood

@Blue he said that there are systems for mathematical typesetting other than latex

Yellow

I will just learn hilbert spaces seperately

Anonymous

18:28

@danielunderwood Sure there are

danielunderwood

I find that to be an inconceivable notion

(/s)

Anonymous

@Yellow Wouldn't make much sense to learn linear algebra + hilbert spaces. Better pick up a proper abstract algebra text after you're done with linear algebra.

Yellow

@Blue okay

Anonymous

@danielunderwood Why?

Yellow

thats ma man foucault

danielunderwood

18:30

@Blue it was a joke. I'm sure that there are others, but I've only heard of people using latex

Anonymous

Heh, okay :P

Anonymous

I'm pretty sure that most professional publishers would have something customized for themselves

danielunderwood

I did run into a paper a week ago or so that was typewriter with handwritten equations

Yellow

and this is alexandar grothendieck

danielunderwood

Ahh I figured publishers would just take tex files and apply their own formatting

Yellow

18:31

they are the same

Anonymous

167

Q: Alternatives to LaTeX

Are there any professional alternatives to TeX/LaTeX which produce equal or even better typesetting? Maybe expensive commercial ones. The software counts if it is comparable or superior to LaTeX (with microtype) in typesetting text or math (or both). In any case, please mention both aspects in ...

typography latex-misc

Yellow

one is a god of abstract algebra and the other is a postmodernist boi

danielunderwood

Hmm neat

I'm sad that I can't seem to find the paper I had with handwritten equations. It was something special

Yellow

i bet there are thousands of papers like that

Yellow

18:53

Do you guys know of any papers on thermodynamics, life and suicide????

and also check this amazing paper

link.springer.com/article/10.1007/s00016-018-0213-3

Avnish Kabaj

@Yellow separately or combined

Yellow

combined

combining is fun

Avnish Kabaj

Do you know the weight of a soul?

It's 21 grams

Yellow

no man

dont give that bs

Avnish Kabaj

21 grams experiment

The 21 grams experiment refers to a scientific study published in 1907 by Duncan MacDougall, a physician from Haverhill, Massachusetts. MacDougall hypothesized that souls have physical weight, and attempted to measure the mass lost by a human when the soul departed the body. MacDougall attempted to measure the mass change of six patients at the moment of death. One of the six subjects lost three-fourths of an ounce (21.3 grams). MacDougall stated his experiment would have to be repeated many times before any conclusion could be obtained. The experiment is widely regarded as flawed and unscientific...

Anonymous

18:57

@Yellow Umm.....what.

Yellow

what what

Anonymous

Why do you think they'd be related in any meaninful way?

Emilio Pisanty

15

A: TeX new site theme is live

Boycott this site until and unless the old look is restored! If it's not restored, let's say goodbye and good luck to this site entirely. Why do I say this? It's because I suspect that the only way that the powers that be will ever respect and listen to our views is if we -- and especially the m...

↑ damn

Yellow

Do we both agree that thermodynamics and life (replication, growth, molecular synthesis) is related?

Avnish Kabaj

@EmilioPisanty lil

Math rejected the new design as well

Anonymous

19:01

@Yellow Thermodynamics is related to all physical processes. And your point is?

Yellow

WHY

i did not mean to delete that

i just deleted my point

If so the "function" which maps the alive set to the dead set is also related to thermodynamics

Anonymous

...

danielunderwood

As someone that works on software, people get very unhappy with any sort of redesign

Yellow

How can we "off" ourselves

Avnish Kabaj

@Yellow and a trillion other things

Yellow

19:02

Like?

Avnish Kabaj

Hmmm

I

Get shot

Emilio Pisanty

@danielunderwood well, these are designers by trade

Avnish Kabaj

Now you're going to say that's entropy

Yellow

I want to know why we are allowed to die

Emilio Pisanty

and a large portion of the folks who built TeX and LaTeX

SE ignores that kind of warning at their peril, really

Avnish Kabaj

19:04

@Yellow allowed seems to imply that something should restrict us

What's that something

Yellow

and why did life emerge if it is all doomed to die. It should be related to what happens in the time interval in which we are alive

Anonymous

Ah, Math SE got their redesign. When are we getting ours? :P

Yellow

why for some there is no life, then for a little time life, then no life again

And you can change that lifetime interval by.... killing yourself

Avnish Kabaj

I do not see how this is related to thermodynamics

Looks like god talk

Spiritual stuff

danielunderwood

@EmilioPisanty I mean the comments on how to fix things are reasonable, but boycotting the site if things aren't rolled back are the things I'd respond to with "get used to it"

Yellow

19:06

nope

i am just speculating. trying to find ways to satisfy my curiousity

If you can practically minimize that alive time interval to epsilon, why does it even begin???

danielunderwood

I think there's a very fine line of when to listen to users and when to ignore them though

Emilio Pisanty

@danielunderwood If this was a site about programming in C and Dennis Ritchie and Ken Thompson were top users, and they told you that they would leave, would that change things?

Avnish Kabaj

@danielunderwood Presenting the next Steve jobs

Yellow

anyways if you find anything tag me and link it to me please.

Emilio Pisanty

it's pretty instructive to take your latest latex project, look up the classes and packages it relies on in CTAN, and cross-correlate the authors of those packages with the top user ranking in tex.se

a heck of a lot of them are there

Avnish Kabaj

19:11

Wow

danielunderwood

Hmmm I'll admit that I've never had people unhappy with design that were that important for the topic of the project. Though I still think threatening to boycott due to a superficial change is a bit silly.

Emilio Pisanty

a mass migration to a TUG-hosted alternative would make an enormous dent in the future quality of content of tex.se

@danielunderwood Read more closely. They're hardly complaining about superficial changes.

Loong

also

-55

Q: Mathematics new site theme is live

We rolled out the new site theme for Mathematics. It is live now. What new theme? If you're like, "What the heck are you talking about?", then you should read the Meta Stack Exchange post entitled Rollout of new network site themes (and maybe the posts it links to for the full background). Y...

discussion featured design

Avnish Kabaj

"You are one of the first sites to get a new, unified theme": Please, don't spread the infection any further... — Massimo Ortolano 2 days ago

danielunderwood

I don't really see anything other than people complaining about things like color and spacing. The first comment on the main post that none of the comments seem to be taken into consideration is a bit of a problem, though that was posted on the same day as the main post and it's not like the changes are going to happen immediately.

I'd get it if the mechanics or rules of the site changed, but it looks like only the design from what I see.

Lozansky

19:19

If $H^0$ is the Hamiltonian of an unperturbed system and $\psi^1$ is the first order correction to the wave function and $\psi_a^0$ is a solution to the SE such that $H^0\psi_a^0 = E^0 \psi_a^0$, then is $\langle \psi_a^0 \vert H^0 \psi^1\rangle = E^0 \langle \psi_a^0 \vert \psi^1 \rangle$?

Emilio Pisanty

-11

Q: New TeX site theme coming soon

As mentioned on meta.stackexchange.com several months ago, all network sites will be getting updated themes. TeX is one of the first sites that will be updated. As such, I'm posting the design here so you can see how the new theming will be applied to your site. I want to acknowledge that this w...

discussion design

Lozansky

I guess I'm asking if $H^0$ is hermitian so that $\langle \psi_a^0 \vert H^0 \psi^1 \rangle = \langle H^0 \psi_a^0 \vert \psi^1 \rangle = E^0\langle \psi_a^0 \vert \psi^1 \rangle $

Emilio Pisanty

this is one month old

but yeah, there's certainly some hyperventilation, to be sure

I think Facebook is in the 100 busiest sites? — E.P. 56 secs ago

user54826

@EmilioPisanty Roger that, @EmilioPisanty. I'll find a unique username next month.

ACuriousMind

@danielunderwood I'm personally more irked that this is not the first new design that I remember that nobody asked for and yet there's so many feature requests people are actually asking for that don't get any dev time

2

Avnish Kabaj

19:29

Skullpatrol deleted his account

Sed

Anonymous

@AvnishKabaj Pretty sure (s)he hangs around with a different username.

Avnish Kabaj

user1414

191 1 10

history olympics american-football pro-wrestling terminology trivia

That's him

in trash, May 23 at 8:35, by Avnish Kabaj

@skull :P

danielunderwood

Well I'd imagine that there is good reason for the redesign. If themes are all over the place without constraints, it could be a pain to implement new features. Maybe development time around all the themes was getting into the way of the development of the requested features. I hope that's the case, but I could certainly see a world where it wasn't. I can see it as a bit of a problem if people are giving suggestions that aren't being taken as well.

Anonymous

@ACuriousMind Were there any recent changes to the SE dev team or management? They seem to be behaving strangely lately, with their repeated attempts at making new "codes of conduct" and design changes

danielunderwood

There's also the SO for teams feature that makes me a bit wary. I think it could be useful, but it also introduces something that I could see hurting the site

Avnish Kabaj

19:34

@danielunderwood that's for companies, no?

How is it harmful

Anonymous

@AvnishKabaj Makes important data private and goes against the "always-free" model of SE

Avnish Kabaj

@Blue I think companies use it for company things

Anonymous

I can imagine them making more and more stuff "paid" in the future

Avnish Kabaj

Like I don't think a couple of physicists made a team

danielunderwood

Well red hat has q&a site similar to SE that's only available to paying subscribers. I get the point of it being kind of a support thing, but I could also see SE doing a similar thing with questions that should be public

I think using it as an internal thing could be wonderful so long as they don't try to drag the public side of SE into it

Avnish Kabaj

19:37

@Blue acess chat for only .99$ a month

ACuriousMind

@Blue depends on how "recent" you mean, but over the last year quite a few people stopped working there and they also hired some new ones (most recently 2 new CMs) . The CoC stuff was long in the making but I'm afraid I won't go into details there, partly because I'm not sure I got it right and partly because I'm not sure how public everything is

danielunderwood

Though I won't lie, I wouldn't mind there being a paid part of SE that we could send all the homework questions over to. That could be tough since I don't particularly agree with some of the questions that are classified as homework though.

ACuriousMind

@danielunderwood Teams is meant to be an internal space for customers to organize their knowledge that's not suitable for public Q&A. Not sure how many need that but then I work for a company where most communication is still good old emails :P

Avnish Kabaj

@danielunderwood :(

Anonymous

@ACuriousMind Don't you people have to use something like GitHub?

Anonymous

19:42

Email seems to be pretty inefficient if you're working with a large team

Avnish Kabaj

Slack

danielunderwood

@ACuriousMind I get that that's the intention and I think it's a good idea. I just worry about it becoming a good source of profit and being on a slippery slope to bring in other parts of the site. I suppose that the community may be likely to create a new site of their own if that were the case.

ACuriousMind

@Blue ABAP and Git don't play well together (though that's changing)

danielunderwood

@Blue that's how we do it where I work. Basically just "open up an issue if you have a question"

Anonymous

Okay, that is expected for a COBOL descendant :P

Anonymous

19:43

@danielunderwood Yup, that seems to be the ideal way for most companies

danielunderwood

@ACuriousMind do you have people that specifically work with github to get things like syntax highlighting and such? I've always been curious how they handle support for new languages

Anonymous

@AvnishKabaj "Chat Premium" for 9.99$ a month - get access to unlimited stars and flags XD

ACuriousMind

@danielunderwood there's a Team for moderators and frankly, it doesn't have any features the free main site lacks (except that comment notifications work differently, which makes sense for the smaller scope) . The standard non-company SE user had no reason to be wary of teams at present

danielunderwood

Ahh that's a good thing to hear

Anonymous

Anyone here used ShareLaTeX Premium or Overleaf Premium btw? I'm looking for something which would allow me to keep a track of all the version histories, but the premium version looks a bit expensive and I'm not sure if that's the only option available

Anonymous

19:47

I don't know how the "student discount" works either

danielunderwood

I haven't used them in a while, but I preferred just using git

ACuriousMind

@danielunderwood I don't know, mostly we have people working on making Git work in a useful manner for us at all. Abap, or rather the SAP system, already has a version control system backed right in. You always need to think about Abap not only as a language, but also as living inside this bunch of systems intrinsically connected to it

Anonymous

@danielunderwood Does LaTeX work/render well on GitHub?

Anonymous

I never tried

ACuriousMind

Syntax highlighting is probably not a big problem, given that we already taught it to eclipse

danielunderwood

19:50

Unfortunately not. ShareLatex used to have github CI that was awesome, but they discontinued that. You can hook in travis or a similar ci system to build a pdf and add it to the repo or do it yourself

Built-in version control sounds scary

Oops first was to @Blue second to @ACuriousMind

And for the tex part, one or both of those services may give you pdf diffs, which I don't know that github does

I think the worst part about the services was that they were paid to get all the features while I could use github for free with a slight inconvenience. The services were better for collaboration from what I remember

ACuriousMind

@danielunderwood it's weird, yes. But I think SAP's system ("transport system") actually predates modern version control, so...the curse of backwards compatibility, as so often

danielunderwood

@ACuriousMind is there ever any thought of just rewriting everything?

Anonymous

@danielunderwood I see. Seems complicated :P

ACuriousMind

@danielunderwood believe me, everyone dreams about that constantly :)

danielunderwood

Something something comic where guy gets thrown out of window

@Blue yeah I never got a completely satisfactory environment for handling tex. A lot of people also just use drive/dropbox, which also have some sort of versioning. I will note that github is fairly annoying when you have entire paragraphs in one line

One of the big bonuses of the services is that you don't have to worry about having a giant tex library installed, missing dependencies, and the like. I also remember it dealing with bibliographies easily rather than having to run 3 different commands to get everything handled. Swapping to latexmk fixed that problem for me though

I believe my official position sounds like "good but bad but good but bad" :D

Anonymous

20:06

@danielunderwood "One of the big bonuses of the services is that you don't have to worry about having a giant tex library installed, missing dependencies, and the like." --- that is indeed the best part of ShareLaTeX and Overleaf. But all good things seem to be "not free" ;)

Anonymous

And for bibliographies BibTeX seems great

danielunderwood

Yeah I was lucky that my school had some sort of overleaf subscription for everyone. I think it was because they were an early adopter or something since I get emails asking questions about it. I always kind of wanted the paid version of sharelatex, but I wouldn't pay for it. I suppose I could probably have gotten my research group or department to pay for it though.

And it was either bibtex or biblatex, but I remember there being a sequence of compile the paper without references, compile the bib file, then link references into the paper. Or something similar

Anonymous

@danielunderwood Yeah, we need to maintain the .bib file separately

Novalium Company

How's everybody?

Anonymous

Anyhow, they say it's $8 per month for students. I might try it after all, let's see

Anonymous

20:11

(if I get the student discount)

Anonymous

@NovaliumCompany Hi!

Lozansky

Degenerate perturbation theory question: is the first order correction to degenerate eigenvalues $E_1^1 = E_1^0 + E_{-}^1$ and $E_2^1 = E_2^0 + E_{+}^1$?

Novalium Company

@Blue How are you? 😃

Anonymous

Lots of work to do but procrastinating ;_;

Anonymous

Anyhow, it's Saturday night. One more day left before Monday begins XD

danielunderwood

20:15

The everlasting struggle

Novalium Company

Its summer holiday here, relaxing...

I'm trying to understand wave diffraction and Huyhen's things more clearly. Glad that I got a book to follow 😊

Anonymous

Great :) There are some nice videos too. But probably you should watch them after reading the theory

Anonymous

I'm stuck with JFETs here, lol. Transistors driving me crazy :P

Anonymous

Thousands of variations of the same thing

Novalium Company

Are they really that annoying 🙂 ? They seem important tho.

danielunderwood

20:19

I still have no idea of applications to actually use a transistor for unless I wanted to build memory or something

Much less when to use the various types

Anonymous

@NovaliumCompany They do get annoying soon....when you have to read 900 pages only based on variations on BJTs and JFETs

Anonymous

:P

Anonymous

But some people in my class like these stuff

Anonymous

I seem to enjoy the digital logic and signal processing classes more

danielunderwood

@Blue I think I'd make it about 1% through before starting to question my sanity

Anonymous

20:23

@danielunderwood Ah, well a simple application would be signal "amplification"

Anonymous

@danielunderwood Heh XD

Novalium Company

@Blue Game got over 200 installs and still grows 😆 We'll see how it goes.

Anonymous

@NovaliumCompany Nice! Are you running ads? :D

Novalium Company

About to implement them after a few days. Also in app purchases.

danielunderwood

Ahh yeah I have seen them used in amplifiers. Any time I've needed an amplifier, I've just grabbed a standard op amp though

Although I think the ones I've used are just transistor amplifiers internally

Speaking of electronics, are there any books or websites that just have a bunch of circuit diagrams and their characteristics? Like I have a book that give a number of circuits and IV curves, but it would be neat to have a whole catalog of them

dmckee

20:32

@danielunderwood The jiggery-pokery that is done to get rid of the voltage offsets and small signal non-linearity and so on inside solid-state op-amps is a art in and of itself, but yeah, they run on transistors.

danielunderwood

Ahh yeah I have seen all sorts of suggestions on how to improve on transistors and I'd imagine op amps include those based on intended application

dmckee

Operational amplifier

An operational amplifier (often op-amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op-amp produces an output potential (relative to circuit ground) that is typically hundreds of thousands of times larger than the potential difference between its input terminals. Operational amplifiers had their origins in analog computers, where they were used to perform mathematical operations in many linear, non-linear, and frequency-dependent circuits. The popularity of the op-amp as a building block...

danielunderwood

And I think my cat wants me to procrastinate. She's chosen my reading chair as her place to sleep for 20 hours a day this week

Man electrical engineers must have a lot of patience

Novalium Company

Guys, how does diffraction occur? I mean, why does the wave bend, can Huygen's explain that?

dmckee

@NovaliumCompany How could waves not bend?

I mean, you need three things to make a wave:

(a) an inertial tendency (plain inertia for matter displacement waves)

(b) a resoriing tendencey (the tension in the string for waves on a string, level seeking for surface waves on a fluid...)

(c) a spacial coupling (each part of the string pulls on the parts near by, liquid flows to or from nearby spaces...)

And part (c) means that any disturbance here causes things to change there where "there" means in every direction supported by the spacial coupling .

So because water flows away from high places in or toward low places from every direction the coupling involves all directions along the surface. So Huygens' wavelets propagate in every direction along the surface which is why they are circles.

And similar arguments can be made for other kinds of waves on surfaces or in volumes.

Novalium Company

20:51

@dmckee Cool, thanks. I'm still not familiar with Huygen's so I better go do that first.

Anonymous

@dmckee You need to write an introductory physics book! That is an excellent way of explaining the wave model of light, by making comparisons with classical string waves and water waves, at least for beginners :D

dmckee

My experience with that approach to explaining the "Why" of Huygens' principle is that people either love it or hate it.

There is something to be said for idiosyncratic treatments, but for books intended for a wide audience the expectation is treatments that work reasonably well for most people and I don't think this qualifies.

It is on my list of things to write up in a short form.

Anonymous

Well, I can imagine the analogies being made much more precise and derivations added for the diffraction formulae apart from introduction of other more complicated mathematical treatments. But at least this preliminary form is good for intuition. So, yeah, you could put it up on a public blog when you have the time. It would help beginning physics students :)

Anonymous

21:07

(Or if you're feeling lazy to make a blog, just look for some question related to this topic :P There are lots of old PSE questions which could benefit from more comprehensive answers)

Novalium Company

Is Huygen basically saying that every wave is made up of smaller spherical sources of waves?

Anonymous

@NovaliumCompany No, the precise statement is: "...every point on a wavefront is itself the source of spherical wavelets."

dmckee

@NovaliumCompany He gives a construction for using wavelets to describe the overall propagation of the wavefront.

But the rest of wave optics is built on the same idea, just dealing with the interference effects arising from the full wavefront (i.e. from the wavelets).

Novalium Company

Hmm, cool. I'll continue with it tommorow (00:20 here). Thanks @Blue and @dmckee for the time spent and attention given :-)

Physics Meta

22:50

0

Q: Is my question in the wrong place?

How much degenerate matter is there, compared to other states of matter? hasn't had any replies. I'm thinking about starting a bounty on it, but maybe it would be more appropriate in Chemistry or Astronomy SE instead?

discussion

enumaris

hmmmm

danielunderwood

23:35

woah @enumaris on a weekend?

enumaris

23:55

lol

my RL algorithm is performing oddly

danielunderwood

Put it in some sort of metalearning...then put that in another...then another

ez

enumaris

it learns only 1/10 of the time lol

feels like that's just random luck maybe

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