The h Bar

12:04 AM

Has anyone ever heard of a variable of integration $d^3\mathbf{v}$ being rewritten as $d|\mathbf{v}|d\Omega$?

I am reading a paper that uses this result as if its obvious, but I can find no reference to it been true.

A link to the paper is [here](https://doi.org/10.1063/1.1674619), and the substitution is used on page 380 of the journal or 6 of the paper PDF.

alarge

@user400188 I don't have access to the paper, but do you mean like the Jacobian determinant in a change of variables?

user400188

I think the change of variable here doesn't require any considerations of the Jacobian determinant. That is to say that the limits of integration don't change.

The reason for this is that they are written symbolically. Our integral is $\int_{\mathbf{v}\cdot\mathbf{n}>0}d^3\mathbf{v}$. So when we change the variable $d^3\mathbf{v}$ to $d|\mathbf{v}|d\Omega$, presumably the equation defining the integration range $\mathbf{v}\cdot\mathbf{n}>0$ also changes, but we don't notice it since we never explicitly write what this relation is a function of.

Also, I think I have answered my own question. We are allowed to change $d^3\mathbf{v}$ to $d|\mathbf{v}|d\Omega$ because integration over all velocities in 3D space is the same as integration over all speeds and solid angles.

Thanks anyway @alarge :)

Secret

sounds about right, you are basically splitting the velocity into its direction and magnitudes

danielunderwood

12:20 AM

You guys ever get a day when technology just decides to revolt against you?

DNS...broken. SSH...broken. Phone on a completely separate network? Broken!

enumaris

Not yet

danielunderwood

Really? It happens to me once every few months at least

Maybe technology is just tired of my abuse

enumaris

XD

DNS broken means you can't access the website?

danielunderwood

Uhh if it was completely broken. It's actually just my laptop that's being weird. External DNS lookups are fine, but internal ones aren't resolving even though it seems to see the correct DNS servers

Maybe it's my fault for being one of the crazy people running home DNS

enumaris

o.o

My current company asked me to help them interview for the role that will replace me...they will pay me to interview people even after my 2 weeks are up...is this common..

offering side-money to interview a replacement?

danielunderwood

12:27 AM

It's like an express version of you being a manager!

Did you take a new job?

enumaris

yeah

my new job has direct reports so I would be a "manger" in that sense

if I stayed, I would also have direct reports...

but they want me to help them interview for the new role...I'd like to help, but I'm not sure if it's common practice

danielunderwood

Can't say I've ever heard of it, but I'm just a small fish. I certainly haven't been interviewed by anyone that was leaving though

enumaris

well in this scenario I'd have left

like I would already be working at the other company

danielunderwood

potato potato

enumaris

I don't think they can find a replacement within the 2 weeks that I'm here

danielunderwood

12:39 AM

puh-tay-toh puh-tah-toh

(in case the first one wasn't clear)

enumaris

it was clear

tho I don't know anyone who pronounces it potato

danielunderwood

I always pronounce it potato

enumaris

so how are you liking ur new gig?

don't know much about it, u got any details u can share? What u do...etc...

big company or start up...

etcetera etcetera

danielunderwood

12:55 AM

It's pretty neat so far, though most of what I've done so far amounts to training and learning loads of acronyms. I actually don't really know what I can share since they're fairly strict on what's shared. I guess I should actually check with my manager tomorrow for a public description of what I do. It's certainly a big company though

It is taking a bit of getting used to working with a bunch of people in another time zone. They have meetings when it's time for me to have lunch or go home

I will say it's nice actually having a team and some direction. And it feels almost like an academic environment where you're left alone to do your work, but there are nearly endless people doing all sorts of things you can reach out to

enumaris

1:39 AM

@danielunderwood sounds nice :D So you work remote?

Physics Meta

1:53 AM

0

Q: Why are up voting and down voting separate?

To me down votes and up votes should be earned at the same time, but I want to know what the rationale behind them being separate.

discussion

Sir Cumference

2:15 AM

@ACuriousMind I wonder what ever happened to AccidentalFourierTransform

danielunderwood

3:06 AM

@enumaris I've been in the office so far, but I have a setup if I decide to work remote some days. But I worked all remote for my last job and it kind of sucked working in my living space

enumaris

I see..

Physics Meta

5:03 AM

0

Q: Can I cross post a question from MSE?

I have a question posted to MSE which is more physicsy than mathy. If it remains on MSE, is it kosher to repost it here at the same time?

discussion

dmckee

5:43 AM

@Slereah I've worked on some of those mid '80's luggables. In fact my high school CS team (that is the four students taking the second year course in a corner of the room where the first year course was being taught) took two of them to a programing contest mostly attended by area colleges. We finished in the middle of the pack and felt pretty good about it.

Slereah

7:37 AM

John Rennie

8:01 AM

@Slereah the Bogdanovs?

GodotMisogi

8:27 AM

0

Q: Possible infinite path integral question(quantum electrodynamics). Any quantum physicists out there?

This question came from a sci-fi show(refer to tagged link->EPISODE QUESTIONS-Physics Bowl). It seems like a Feynman diagram requiring path integrals. Can anybody solve it with a detailed step-by-step solution(if it is right, that is) that can help even a layman understand it to a maximum exte...

quantum-mechanics

Would this be considered off-topic?

Anonymous

@GodotMisogi The hazy screenshot is definitely not helping. And it would possibly classify as homework.

Anonymous

> Can anybody solve it with a detailed step-by-step solution(if it is right, that is) that can help even a layman understand it to a maximum extent.

GodotMisogi

@Blue I'm pretty sure that screenshot's the best one can do, since it's from an episode of The Big Bang Theory

Anonymous

@GodotMisogi They need to type it out. :)

GodotMisogi

But it's hypothetical and not relevant to his main question, which is about a certain calculation from P&S's QFT book.

Anonymous

8:31 AM

34

Q: Discouraging screenshots of questions - at least the textual part

[This was originally posted as an answer to another question and was transformed into a question following a comment to this effect.] To discourage rapid postings of the type alluded to in another questions, I would suggest the community simply close questions containing screenshots of text. I ...

discussion questions mathjax tex

Anonymous

@GodotMisogi If it's not relevant it shouldn't be there!

GodotMisogi

I know, that's why I'm bringing attention to it as possibly off-topic, but I'm not sure

John Rennie

It's the tree level term in the scattering of an electron from a muon, so it's presumably a simple calculation for those who know about such things (i.e. not me).

In that sense it should be closed as homework.

Though what I suspect is the OP wants to know how such calculations are done, which is probably too broad.

Though if someone wants to have a go at explaining the calculation in laymen terms that seems a worthy answer.

Anonymous

I doubt any answer would actually help the OP.....apart from quenching their thirst for trivia.

Anonymous

If someone could type out the contents of the image, and beat the rest of the question into shape, it might work.

GodotMisogi

8:35 AM

It's impressive to see a high-school student type what he's typed, but those are more syntactical understandings, I guess.

Anonymous

I don't see anything impressive there apart from a few buzzwords...

GodotMisogi

Hm, conceded. That's not a path integral at all

user2723984

I think what they might be looking for is some layman's exposition about QFT, what Feynman diagrams are and how are they used to calculate results of experiments, I doubt an SE answer, or reading P&S, can tell them much that they understand at high school level

user351417

You can't ask for 'a description which a layman can understand' and 'rigorous mathematics' simultaneously.

user2723984

well there's only one of those two accessible to an high school student

user351417

8:40 AM

Exactly. It's like the part about the math was there just to encourage answers to contain fancy notation or some jazz like that.

GodotMisogi

Unless you're Stephen Wolfram

Anonymous

The Big Bang Theory - Sheldon at Physics Bowl - VOST.FR

►

Anonymous

It's a fun episode, nevertheless. :P

user351417

I've never watched the show myself, but apparently a lot of the physics in it is hot air.

GodotMisogi

@Blue Please, can we keep cringeposting off the channel? :)

Anonymous

8:42 AM

@Chair ...that's true.

Anonymous

@GodotMisogi This isn't cringeposting at your level. :P

GodotMisogi

@Chair I have, and it's true

Even with my completion issues, I couldn't watch past season 6

Anonymous

Man, even Motl watches Big Bang Theory!

Anonymous

You're calling it cringeposting...such a disgrace!

user2723984

Clearly the physics is hot air, the point of the show is not to teach physics or to represent it

at least I hope

GodotMisogi

8:43 AM

George Smoot was on it, and he loves the show.

I'll ask him about it next time I see him on campus

@user2723984 The point of the show is to make fun of nerds, and eventually to show that nerds can get hot grills

user2723984

well yes, the point of a show like that is to turn off your brain for 20 minutes

Anonymous

Hot grills?

user2723984

which can be nice

GodotMisogi

@Blue Season 1 was not very objectionable

@Blue Like, that grill is hot, 10/10 would cook on

user2723984

you need just about 0 cognitive abilities to watch it

does the geodesic of a photon depend on its frequency? I would say no based on the equivalence principle, but I can't really justify it rigorously

Anonymous

8:49 AM

@GodotMisogi Anyway, I love the opening theme song. ;)

Anonymous

It has a sweet rhythm to it.

GodotMisogi

@Blue I despise 8s.

Prog music and odd-time signatures have ruined my ability to appreciate most music.

user351417

There're plenty of odd-sounding stuff which are actually in four though...

GodotMisogi

@Chair Sure, but they usually have interesting subdivisions (in odd-times, like 5+3) which add up to 4/4

Anonymous

@GodotMisogi I have normie tastes in music...

user2723984

8:54 AM

is that song not 4/4?

GodotMisogi

Why I Hate "The Big Bang Theory" - Lyle McDouchebag

►

user351417

@user2723984 It is. That's among the things which make it uninteresting (to me)

user2723984

ooh then I misunderstood the problem

GodotMisogi

Although the song I wrote most recently is all 4s...what's the word for that? Hypocrisy?

John Rennie

@Chair a lot of prog is in 4/4 or 3/4. Most of Pink Floyd and Genesis for example.

GodotMisogi

8:56 AM

@JohnRennie Which is why my favourite Pink Floyd song is Money :)

John Rennie

You have to go to the weird side, Van der Graff Generator or Soft Machine to get weird time signatures.

user2723984

well time signature isn't everything, Pyramid song is in 4/4 and it is very odd

user351417

Or Rush.

user351417

Nothing beats Rush for odd times.

John Rennie

Rush aren't weird

GodotMisogi

8:58 AM

But Rush has a lot of odd-times. My favourite band

@user2723984 This sounds polyrhythmic, which makes it interesting.

John Rennie

I wouldn't say Rush use odd time signatures a lot. Most of their tracks are 4/4. The do use odd time signatures occasionally, but I wouldn't say it was distinguishing feature of their music.

GodotMisogi

9:15 AM

@JohnRennie I guess that's true, but there are quite a few tracks that have odd-time signatures. Limelight, Time Stand Still, Stick It Out, Freewill, off the top of my head.

@Chair Well, there is Dream Theater.

John Rennie

@GodotMisogi Tom Sawyer?

GodotMisogi

@JohnRennie Ah right, in the middle, yes. It's not one I listen to very frequently, though. Ironically, my favourite song of theirs is either Afterimage or Mystic Rhythms, both of which are 4/4, lol

John Rennie

If you like odd time signatures I guess anything jazz related would be of interest. Soft Machine or King Crimson are the obvious suggestions.

GodotMisogi

I listen to a lot of King Crimson, haven't heard Soft Machine, though. Thanks for the recommendation!

John Rennie

Personally I think a little Soft Machine goes a long way, though they've sold a fair few albums over the years so obviously someone likes them.

I like some King Crimson albums: In the Court.. and Red for example. But some of their albums are pretty tedious. Starless and Bible Black springs to mind as especially tedious.

Novalium Company

9:31 AM

Good morning!

John Rennie

Morning :-)

GodotMisogi

@JohnRennie Do you like The ConstruKction of Light (song)?

John Rennie

If I'm honest I don't know the album very well.

GodotMisogi

@JohnRennie I'm listening to Bundles (album) right now; already enjoying it

John Rennie

9:47 AM

I generally like prog, but Soft Machine is a step too far for me :-)

Anonymous

10:25 AM

Hah, Preskill uses $\mathfrak{h}$ to denote $\Bbb C^{2^n}$. Finally found a legit use for \mathfrak.

Anonymous

Actually, I'm not sure it's \mathfrak. It looks like:

user2723984

Lie algebras are usually denoted with a mathfrak lowercase letter, which makes it a nightmare to note them by hand

Anonymous

@user2723984 Hehe, I did hear once that people use it for Lie algebras.

Anonymous

I know someone who's comfortable with writing all those weird symbols on the blackboard.

user2723984

10:31 AM

I have enough difficulties already with the greek letter xi, which should be abolished

Anonymous

Thorne–Hawking–Preskill bet

The Thorne–Hawking–Preskill bet was a public bet on the outcome of the black hole information paradox made in 1997 by physics theorists Kip Thorne and Stephen Hawking on the one side, and John Preskill on the other, according to the document they signed February 6, 1997, as shown in Hawking's The Universe in a Nutshell. == Overview == Thorne and Hawking argued that since general relativity made it impossible for black holes to radiate, and lose information, the mass-energy and information carried by Hawking radiation must be "new", and must not originate from inside the black hole event horizon...

Anonymous

I forgot what the result was. Reading...

Anonymous

> As of 2008, Hawking's argument that he has solved the paradox has not yet been accepted by the community, and a consensus has not yet been reached that Hawking has provided a strong enough argument that this is in fact what happens.

John Rennie

@Blue as I recall Hawking was persuaded by the AdS/CFT description of a black hole. But exactly what AdS/CFT means for real black holes is controversial so it is not universally accepted that Hawking was right.

Anonymous

10:48 AM

@JohnRennie I see, interesting! I don't know much about the physics of black holes yet. And AdS/CFT is apparently in the QFT/string theory domain. Still working on it. :)

John Rennie

@Blue the trouble is that Hawking's original work on radiation is a semiclassical result i.e. it uses a fixed, classical, spacetime curvature and the radiation does not contribute to the curvature.

This is probably fine for large slowly radiating black holes, but in the last stages of evaporation the radiation intensity will be very high and the approximation will break down.

But without a theory of quantum gravity no-one has any idea what happens.

Anonymous

Oh. Is radiation supposed to contribute to the curvature? (I didn't know) What's the relevant search word?

John Rennie

backreaction

Anonymous

Thanks! I'll read.

Physics Meta

1:47 PM

1

Q: Community Promotion Ads — 2019

2019 is here! And with the new year, as usual, comes a new iteration of Community Promotion Ads! Let’s refresh these for the coming year :) What are Community Promotion Ads? Community Promotion Ads are community-vetted advertisements that will show up on the main site, in the right sidebar. The...

discussion community-ads

Emilio Pisanty

@PhysicsMeta now?

sigh

Beta Decay

2:00 PM

Hey, does anyone know where can I get data for the theoretical emission spectra of molybdenum?

Ender Look

2:44 PM

According to this like, and all that weird equations, does that means generate negative mass consumes energy as positive mass does? I thought negative mass would generate positive energy, or at least consume negative energy.

Emilio Pisanty

3:44 PM

@BetaDecay emission of what?

@Blue that does look like a $\mathfrak h$ to me.

no, it's more likely an upper case $\mathfrak H$

... or what Fraktur thinks is upper case, anyways

don't use fraktur here, though. The last time we talked about this, somebody got so upset about how messed up with it that they went and broke chatjax.

(for full disclosure, that somebody was me)

Slereah

There's plenty of mathfraks used around

Hilbert spaces, algebras, categories, vector spaces

Beta Decay

4:08 PM

@EmilioPisanty Ah sorry, I'm trying to plot a theoretical Bremsstralung radiation curve from 35 kV molybdenum anode onto my experimental data of count rate against wavelength

John Rennie

@BetaDecay x-ray emission then?

Beta Decay

Yap

John Rennie

It'll be pretty boring. Just the usual diffuse spectrum with a couple of K and L lines superimposed.

Beta Decay

Ah ok thanks

kartik c.p

4:22 PM

@ZeroTheHero Thank you

@JohnRennie Long back, i heard you saying physics is unstable. i felt wired , and strange.

@JohnRennie can you tell me more about it

John Rennie

@kartikc.p Let me have a search and see if I can find the posts ...

@kartikc.p I can't find anything. What were we talking about?

Anonymous

@EmilioPisanty Yep, it does look more like the upper case H in Fraktur. I frankly don't understand Fraktur, but it looks cool...

Anonymous

4:38 PM

I'll use it in one of my questions soon, lol.

Emilio Pisanty

@Blue every time someone uses fraktur on student-facing text, a kitten dies

(per student that sees the fraktur, that is)

@Slereah you mis-spelt "misused"

enumaris

hmmm

ZeroTheHero

4:53 PM

@kartikc.p Yes I have the book in my hands... 134 pages. Take a standard printer page and split it by 2 to get a standard page of that book so really a digest of the full theory.

Physics Meta

0

Q: Why it doesn't show correctly when someone was online?

Whenever I click on Anyone's profile to check if available(online) or even my profile,it doesn't show correctly. When I click on my profile it should show online, but it just show last seen a random time ago

discussion feature-request bug profile-page

kartik c.p

@JohnRennie you were trying to say that there may be some undiscovered theory that could destroy Some parts of the physics (SR and GR etc) , you chatting with some other guy

user351417

@Blue Meanwhile, I have a textbook which uses a serif font for plain text and a sans font for all equations.

kartik c.p

@GodotMisogi Why we hate big bang theory .cuz there
is one indian

user351417

@kartikc.p That's no reason to hate it. Funnily enough, they didn't make whatshizname an engineer.

Anonymous

5:09 PM

@Chair Koothrappali

Anonymous

And heh, that would have been fun.

Sid

Since when do we hate Big Bang Theory?

Anonymous

We don't. :P

John Rennie

@kartikc.p I don't remember that. Sorry :-(

kartik c.p

@JohnRennie hmm...

ACuriousMind

5:14 PM

@Blue I do :P

user2723984

forget the FCC, if there's one thing that truly divides the physics community, it's The Big Bang Theory

Anonymous

@ACuriousMind Why though? I can understand that a lot of the buzzwords they say and the equations they write are nonsense, but apart from that it's a pretty decent comedy. :P

Anonymous

@user2723984 Point.

kartik c.p

@JohnRennie you mean GR is some fundamental structure that built in the universe . just like HUP , if so why could not enstien tell why exactly space curves

user351417

It's rather interesting that "why couldn't so-and-so happen" sounds perfect to me, but "why could not so-and-so" sounds unfamiliar.

John Rennie

5:21 PM

@kartikc.p GR is a description of the universe and in GR the curvature is a purely mathematical concept. How far this mathematical notion of curvature is related to what actually happens we don't know. In fact I'm not sure what the phrase what actually happens means.

In physics all we ask of our theories is that they make the correct predictions i.e. the theory correctly tells us what will happen when we do an experiment or make a measurement.

The question of whether the theory really describes the world or not is a complicated one.

ACuriousMind

@Blue Oh, I have nothing against techno-babble (I love Star Trek, after all :P). I dislike the humour of the show. It (or at least its laugh track) considers many nerdy activities to be inherently ridiculous. It's a show ostensibly about nerds and yet it still laughs at them.

I don't enjoy a "comedy" that obviously expects me to find the idea of a bunch of people being into cosplay or online role-playing or whatever else funny in itself.

John Rennie

I have never seen Big Bang Theory. A lady I know bought me the boxed set on the grounds I reminded her of Sheldon - I suspect that wasn't a declaration of romantic interest.

5

Anonymous

@JohnRennie Looooool

kartik c.p

@ACuriousMind why did you change your DP

Anonymous

@ACuriousMind I see. :P

ACuriousMind

5:29 PM

@JohnRennie The best thing about not being a professional physicist is that I never again have to endure the "Oh, like Sheldon?" response when people ask me what I do :P

Anonymous

@kartikc.p The horns were growing too big.

user351417

Weren't those ears?

John Rennie

@ACuriousMind :-)

enumaris

@ACuriousMind Oh, so you used to be like Sheldon?

4

ACuriousMind

@kartikc.p I change it regularly. It gets boring to always wear the same old face

Anonymous

5:29 PM

@Chair Multi function-ed ;)

ACuriousMind

@Blue ....horns?!

How dare you call elven ears "horns"?

user351417

@Blue Hat holders for the winter bash?

ACuriousMind

@enumaris ::eye twitches::

enumaris

;)

kartik c.p

Can any tell me how to change our user name?

ACuriousMind

5:33 PM

@kartikc.p I don't know about "our", but you can change your username on your profile page. Go to your profile, there should be a tab "Edit profile & settings" where you can change your display name. Be warned that you can only change your name once every 30 or so days on a single site.

John Rennie

Does this actually mean anything. Genuine question not a snark. I think the answer is no but don't know enough about the subject to be sure.

-1

Q: Field Coupling in QFT

I'm trying to understand field coupling in QFT in more detail, using a free electron as the simplest example. I understand that an excitation in the electron matter field couples to the EM field to create a local EM excitation (in approximately Coulomb distribution) which can be interpreted as a...

quantum-field-theory

Mo_

I dislike almost anything described as "popular science". But Big Bang theory is not even trying to explain science for all but to stereotype scientists for all.

user2723984

@Mo_ that's not the point of a show like that, it's not a documentary

if anything, it's blatantly sexist and racist, especially in the first season, that's more troubling than the physics buzzwords...

Emilio Pisanty

41

Q: Why do we use AC for long distance transmission?

Why do we use AC (Alternating Current) for long distance transmission of electrical power? I know that AC is such a current that changes polarity (magnitude and direction) and has fixed poles.

electricity electrical-resistance electrical-engineering

the Axiom of Choice has long been known to be a requirement for long transmission of distances

user2723984

I thought we used air conditioning

ACuriousMind

5:52 PM

@JohnRennie No, I can't make heads or tails of the question. It is a strange mix of classical and quantum pictures, and it is unclear how much of either the classical or the quantum theory OP really understands.

user2723984

6:14 PM

is charge quantized in non relativistic QM? Is there a charge operator that commutes with the hamiltonian? It seems to me that global $U(1)$ invariance leads just to the conservation of probability density, but I don't know what I'm doing

ACuriousMind

@user2723984 Yes, charge is quantized if you know that the symmetry group really is $\mathrm{U}(1)$ and not $\mathbb{R}$.

user2723984

Well, clearly I don't, I know the Lagrangian doesn't change under the transformation $\psi\rightarrow e^{i\alpha}\psi$ and the associated conserved charge is $i\psi^* \psi$ I think, what do you mean?

ACuriousMind

Okay, in that case, you know the symmetry group is $\mathrm{U}(1)$

There's a subtlety in that you can't tell the symmetry group from the gauge field alone

You need to know how a charged field transforms under a finite global transformation.

But if you know that ($\psi \mapsto \mathrm{e}^{\mathrm{i}\alpha}\psi$), then it's okay

user2723984

but how is $i\psi^*\psi$ related to the electric charge?

ACuriousMind

6:29 PM

@user2723984 It's the zero-th component of the Noether current, so it is the charge density.

user2723984

yes, it is a charge density, but if you asked me to interpret it I would say that it's the probability density of the wavefunction, multiplied by $i$ for some reason, what's so electric about it? And since $\psi$ is not an operator, what would be the charge operator that defines the quantum number?

ACuriousMind

Wait, what do you mean, "$\psi$ is not an operator"?

I think you need to explain your exact setup in more detail here for me to understand what you're really asking

enumaris

$\mathfrak{\psi}$

oh I can't frak a psi

user2723984

uhm I may have missed something in transitioning from QM to QFT, but I never thought of the wave function as an operator in non relativistic QM

ACuriousMind

Alas, I've go to run. If you ping me I'll get back to you when I return

user2723984

6:33 PM

thank you, I think I have to figure out better what I'm really asking

ACuriousMind

Ohhh, non-relativistic QM. In that case, all we can say is that $\mathrm{U}(1)$ charges are quantized because the representations of $\mathrm{U}(1)$ are discrete and labeled by integers (just like the spin representations of $\mathrm{SU}(2)$)

Anyway, gotta go

Avnish Kabaj

6:54 PM

Fake Nerd/Geek Starter Pack:

1. Minimimalism

2. General Theory of relativity

3. I'm totally like Sheldon/I get all of his jokes

4. Apple

Oh gawd it's too late to delete

I should really think before speaking

Most of my jokes sound funnier in my mind

2

bolbteppa

2

enumaris

sin(x) and x are different tho...

what's the meaning...

bolbteppa

You're missing out on the best engineer jokes

$\sin x \approx x$

enumaris

ah, the small angle approximation lol

Sid

@enumaris Who said they are different? They are the same.

enumaris

7:08 PM

For small values of x they are approximately the same

(expressed in radians)

bolbteppa

What's a radian

enumaris

isn't it the counterpart to the ulnian

bolbteppa

I completely forget that whole qualifier about units in taking derivatives of sin and cos

enumaris

using degrees in physics is gonna lead to a bad time mmm'kay

Sir Cumference

7:37 PM

@bolbteppa Glad there's another r/physicsmemes viewer :D

bolbteppa

My source is spoiled :p

Sir Cumference

Welp mine is too I guess, all my most starred pics are from there :P

On a side note, shameless asking for upvotes:

0

A: Community Promotion Ads — 2019

Anonymous

8:10 PM

I want to make an ad for chat. Gimme some ideas. :P

Anonymous

I don't have any experience. What do you use to make those?

Sir Cumference

@Blue Bunch of public domain stock pics of galaxies, earth, etc. Then just threw them into Photoshop :P

Mo_

Yesterday I had an interview that I kinda feel wasn't as good as it could be

I mean, I didn't really express my enthusiasm and background as I think I could

Do you think it's a good idea to contact the professor (and explain this to him)?

Mo_

8:39 PM

@MusikAnimal I did, and it does closely resemble my father's signature. Seriously it does. I think I did show the resemblance in some talk slide one day 😂

Tweeted by MagnusManske on January 10, 2019 at 11:34 PM in reply to MusikAnimal

t t t t

9:23 PM

anyone have the book "a guide to feynman diagrams in the many body problem" ? it's very popular but i have a hard time and i spotted a handful of typos (it's the 2nd edition... what the heck?)

Physics Meta

9:45 PM

0

Q: am I allowed to ask a user to be an editor for me

I am legitimately curious because if I find someone who understands me can I ask them to edit all my questions that others might not understand?

discussion editing

enumaris

10:01 PM

bowchickawowow