The h Bar

John Rennie

16:03

rob

I guess it's chat session time! I don't think I've ever actually been present for one of these.

John Rennie

That banner has been showing the wrong end time for the chat session for years!

rob

I think there's usually some guidance to the discussion, but I don't know the regular format. Anybody want to take the lead?

Nog Shine

@rob Me neither and I found a bug in your site design. :P

John Rennie

@rob to be honest the chat sessions are largely moribund these days.

rob

16:04

@JohnRennie Seems to be correct now?

John Rennie

@rob not here ...

rob

@NogShine The place to report bugs in the new site design is probably this meta post.

Anonymous

@rob "busy"? ::peeps out of rabbit hole::

John Rennie

Hmm, if it's correct for you I wonder if it's a time zone conversion problem ...

rob

@JohnRennie What time is it supposed to end? I thought it was thirty minutes, starting six minutes ago?

Anonymous

16:06

@rob It's 1 hour

enumaris

3

Q: Average Kinetic Energy in SHM

Question: A particle of mass m executes simple harmonic motion with amplitude a and frequency v. The average kinetic energy during its motion from the position of equilibrium to the end is? Problem: For trying to find the answer I used integration to find the average value of the velocity ...

harmonic-oscillator

John Rennie

The chat session is an hour long. It ends at 17:00 UTC.

enumaris

oomph, this closed question is now a hot topic

how does that work

lol

Anonymous

@enumaris It was closed just 4 mins ago

Anonymous

Probably went in the HNQ pile before that

user351417

16:07

I remember a couple of months back, we had a situation where 3 in the top 4 questions in the 'hot' tab were closed. One was opinion-based, one was off-topic, and the other was god-knows-what.

enumaris

fun beans

Anonymous

The HNQ algorithm is still a big mystery

user351417

eventually one of them (the opinion-based one) got reopened though...

user351417

@Blue I think I saw something on meta se ages back about how questions with pending close votes should not become HNQs

rob

I used the uBlock item picker to hide the HNQ sidebar everywhere. It's made my StackExchange experience better.

user351417

16:09

Clearly that wasn't implemented; I don't remember if it was well-recieved.

Anonymous

@rob I do come across some good questions on non-technical sites, using the HNQ

user351417

@rob SOX has an option for that too. It even attaches a flame icon next to the title of the question if it's HNQ

Anonymous

It doesn't work for the technical sites

rob

@Chair SOX == "Stack Overflow Ox"?

Anonymous

87

Q: Stack Overflow Extras (SOX)

SOX v2.3.0 Stack Overflow Extras (SOX) is a project that stemmed from the Stack Overflow Optional Features (SOOF) project. The SOX userscript adds a bunch of optional features to all sites in the Stack Exchange network. These can be toggled on or off from an easy to use control panel (see s...

script tampermonkey

user351417

16:11

@rob I have no idea. I started using it just a couple of days ago. I'll find the thing on stackapps in a moment

user351417

Ah, blue seems to have gotten that link.

rob

@Blue Oh, that.

John Rennie

I think you have to relax, breathe deeply and learn to love the HNQ.

user351417

Sir Cumference

Welp I'm actually contributing to SOX, if you have any suggestions tell me

Anonymous

16:13

@SirCumference Convert the hamburger into a bar

Anonymous

on the top of the page

user351417

@SirCumference Lovely. You see that misplaced "Ask question" button?? That happens everywhere, EVERYWHERE we find the flame. Just kidding; SOX is fabulous; makes so many things easier. I feel so cool because I have a mod diamond on my top bar.

Sir Cumference

@Blue Uh what

user351417

It tells me if there are new meta posts.

Curious Fish

16:14

It says that this chat is ending in 17 minutes?

Sir Cumference

@Chair Oh yeah I remember the hell it took to fix that after the new topbar...

rob

@Chair Huh, interesting.

Curious Fish

Oh hello Chair I'm a big fan

Anonymous

Sir Cumference

Also: ugh, it does misplace the ask question button

Anonymous

16:15

@SirCumference ^

Anonymous

Having to click that drop down menu is annoying

Anonymous

Can it be added as a bar instead ?

user351417

@rob It lights up blue! And when I click it, it gives me a list of new posts (questions and answers) on meta which I haven't read.

Anonymous

Like this ^

John Rennie

16:16

@CuriousFish that's a bug.

Sir Cumference

@Blue Wait I may be stupid but I don't see that

Curious Fish

Oh thx @JohnRennie

Anonymous

@SirCumference First deactivate the side bar

Anonymous

From your settings

Anonymous

(preferences)

John Rennie

16:17

@CuriousFish the bug has been there for as long as I can remember. At least five years :-)

Sir Cumference

ah, k. You'd like to add those to the bar?

Curious Fish

We must be moving pretty fast for 17 seconds to last five years, lol

Anonymous

@SirCumference Yup, that'd be helpful!

Sir Cumference

Hmm...

Doesn't the sidebar already do that, basically?

Anonymous

Sidebar takes up a lot of the screen space

John Rennie

16:18

@SirCumference yes but the sidebar wastes so much space

Anonymous

It shouldn't be too difficult to add 4 more buttons to the existing tab bar

Anonymous

I guess

user351417

@Blue I recently collapsed the side bar and I didn't get much more place. But I think I've mentioned earlier that since I have a small, high-res display which I keep zoomed out, I spend a lot of time looking at white space:P

Curious Fish

My computer isn't even loading half of the images on this screen

Anonymous

@CuriousFish Try refreshing

Curious Fish

16:21

Tried, it's all still pieces of paper with hills and clouds

Anonymous

Hmm, maybe it's because of a slow net connection

Anonymous

It happens to me sometimes

Curious Fish

Likely, I'm in school rn and a hundred ppl are using wifi

rob

In physics news, the physics Nobels were announced this morning.

6 hours ago, by GPhys

Congratulations to Arthur Ashkin (1/2), Gérard Mourou (1/4), and Donna Strickland (1/4) for winning the 2018 Nobel Prize in Physics for their work on optical tweezers.

Curious Fish

Amazing! Congrats

to them

rob

16:22

Half for the invention of optical tweezers, and half for (iirc) femtosecond pulsed lasers.

Sir Cumference

@JohnRennie So I took a look at the elements. The side bar doesn't seem to actually remove space, it just shifts the content to the right

Meaning questions are still just as wide, etc.

Curious Fish

Middle school is annoying lmao

John Rennie

@SirCumference yes, but since I want to squeeze the SE browser window alongside the other stuff I'm working on I want the window to be as small as possible and still show everything.

Sir Cumference

@Blue Yeah but I gotta think about how I'd place it, and whether it'd be more of a pain to maintain than to keep

Curious Fish

optical tweezers would be a really cool addition to science

What about a pencil that had a tip the width of an atom?

Sir Cumference

16:25

Ah, I've got an idea, tell me what you think. How about when you hover over the top bar, a small bar comes down containing the links?

Curious Fish

Or the smallest animation ever, moving atoms one by one to create a picture!

That one's already been done, though.

Anonymous

@CuriousFish It already is

Anonymous

From the 1980s

rob

@CuriousFish By "would be," do you mean "is"?

Emilio Pisanty

@santimirandarp Only for a small range of parameters and by doing a bunch of brutal approximations.

Curious Fish

16:26

yeah yeah, is

lol

True, I guess

Idk, I've only heard about optical tweezers five minutes ago

Emilio Pisanty

Unless you want to get down into the reeds, you're better off just looking up the vibrational frequencies and postulating the vibrational oscillation ODE from scratch

user351417

@SirCumference I don't think I'd use that... if I try to move my mouse around to the list of tabs on my browser, I'd keep opening and collapsing that. I think that these things which expand on hovers are best in places which aren't usually scrolled over.

user351417

Is it a huge space issue if it just stays pinned open permanently?

Sir Cumference

@Chair That's true. I'm just trying to think of a way to avoid moving other elements of the page around

Akash. B

When is the event?

Curious Fish

16:28

Event?

Sir Cumference

@Chair I mean @JohnRennie mentions he keeps his windows as small as possible, so it could be an annoyance

rob

@Akash.B This is it! It is a chat session.

Lozansky

Isn't every chat session a chat session

user351417

I guess that we're already complaining that there are way too many distractions on the front page: banners about how SE works, HNQ lists, notifications about cookies... but I imagine that those are largely for new users, not those who are familiar enough to install userscripts.

ACuriousMind

Clearly we're not sessioning hard enough.

Curious Fish

16:29

Ah, I see.

Akash. B

So what's the topic

Curious Fish

Physics.

user7777777

The notice to new users about blatantly posting homework questions isn't clear enough

ACuriousMind

Mar 24 '15 at 16:04, by ACuriousMind

C'mon session harder

user351417

@SirCumference I guess it is kind of tricky for me to comment because I have a pretty messed up system too: high resolution, 14 inch display, and tiny zooms.

rob

16:30

@user7777777 I'm not sure about that.

John Rennie

@Akash.B we don't really have topics these days. People just chat about whatever they want.

Abcd

Mar 24 '15 at 16:07, by John Rennie

But homework is set to teach students physics, and teaching students physics is good

user351417

@user7777777 google.com/…

rob

I have the idea that folks who want to ask lazy homework questions don't read instructions about how to ask things.

Abcd

@JohnRennie then what's the point of sending an invitation to everybody "Live Event in H bar etc"

user351417

16:31

No results :(

Anonymous

@SirCumference Actually scratch that. Could simply the reference link be changed when we click on the site logo? I'd like it to direct me to the Newest Questions page instead of the Active page. I think that would solve both of our problems

John Rennie

@Abcd I think homework questions work very well in the chat rooms, but I also think they are out of place on the min site.

Curious Fish

@ACuriousMind s e s s i o n i n t e n s i f i e s

ACuriousMind

@Abcd You only get that invitation if you've recently been in the room or if you have registered for the event

user351417

@JohnRennie The problem is that they don't have the rep needed for chat.

Abcd

16:31

@ACuriousMind But its pretty useless

Curious Fish

k i'm done bye

Abcd

When nothing special happens

user351417

@ACuriousMind Does anybody actually manually register?

John Rennie

@Abcd that's largely historical. The room used to be very quiet so we arranged the regular sessions to try and increase interest. These days the rooms are pretty lively, and we've never got around to cancelling the scheduled chat session.

Student404Mus

why always h-bar session is active rather than others are always inert

ACuriousMind

16:32

@Chair 160 people, but they mostly did so ages ago.

Akash. B

Recently a thing was invented by Donna Strickland, right?

Abcd

@JohnRennie Please cancel it no. Whats the use in continuing the tradition.

John Rennie

@Abcd well it's not doing any harm.

Sir Cumference

@Blue Hmm, now I'm thinking of how we'd allow the user to input a link of their choice in the settings menu

ACuriousMind

@Student404Mus The h bar is one of the most active chat rooms on the network generally.

user351417

16:33

@ACuriousMind Oh, so it's like you sign up once and you subscribe to a lifetime of notifications you can dismiss without consideration? :P

Abcd

@JohnRennie But it aint doing any good as well.

ACuriousMind

@Chair Exactly - just like with every other suscription :)

John Rennie

@Abcd shrug

Akash. B

Spontaneous messages

Student404Mus

@ACuriousMind i see. i like h-bar

Abcd

16:34

Break this tradition please

Emilio Pisanty

@Abcd why?

seriously

John Rennie

@Chair you only need a rep of 20 to chat. Any user too unmotivated to build up a rep of 20 probably doesn't deserve to be ble to ask their homework questions in the chat rooms.

ACuriousMind

@Abcd There are noticeably more people in the room during the sessions, and some people only show up for them. Even if we don't have any particular agenda these days, I see no harm in just leaving it be

Student404Mus

@ACuriousMind what are recommended books or lectures in standard model

user351417

@ACuriousMind I remember my first email id. I used to get like 1 email every month from my parents or someone who pitied me, so I signed up for every tech and physics newsletter I could find. At some point, I found myself receiving a few dozen emails every day, so I deleted it because unsubscribing is way too much work.

Abcd

16:35

@ACuriousMind I think everyone enters because they just get a ping when they are insome other room and they click the blue link

Student404Mus

@ACuriousMind from your experience

ACuriousMind

@Abcd And so they come and chat! What's wrong with that?

Akash. B

Let's chat physics

Anonymous

@Abcd The old-time chat users have some emotions attached to the chat events. It's what helped bring more and more people to the chat initially. To avoid hurting those, let's continue shifting the event cancellation to the future in our usual lazy manner. ;)

xish

How often is the chat just about there not being a real event, though?

enumaris

16:37

hmmm

Sir Cumference

@Akash.B Physics is for nerds

enumaris

SirCumference is a nerdy name >3

rob

@SirCumference Yay nerds!

John Rennie

@SirCumference Luckily there are a few of us around :-)

Sir Cumference

@enumaris Very true :D

ACuriousMind

16:37

@Student404Mus You should ask that someone who's actually read more than one textbook ;)

Sir Cumference

Jesus these stars

Akash. B

@SirCumference I will be a nerd

ACuriousMind

Ah, ain't no chat session without a random star storm

enumaris

stars stars everywhere!

user351417

@Akash.B Lame. We don't do that nonsense here. Look at this image for future reference. :P

Sir Cumference

16:39

lmao

Abcd

star this. I need at least 5 stars!

Sir Cumference

@Abcd Can I downstar that

Abcd

lol

Lozansky

This used to be a wholesome Christian physics chat

Akash. B

Hmm

Abcd

16:40

Lol$^\infty$

Sir Cumference

Star wall is awful

Student404Mus

ok

Anonymous

Lemme screenshot this

Akash. B

Oh too much stars

John Rennie

@SirCumference your trusty mods will go through it and clean it up once the frenzy has died down.

ACuriousMind

16:41

You can't keep starring things, eventually you'll run out of stars

Sir Cumference

@JohnRennie Forgot fun wasn't allowed here :P

user351417

@SirCumference Exactly, I was really hoping that this one would stick around a bit.

ACuriousMind

Dec 1 '15 at 16:41, by ACuriousMind

Always remember, we hate fun.

John Rennie

@SirCumference that's a little harsh. Everyone is free to have fun starring random posts if that's what turns them on.

danielunderwood

@ACuriousMind do you mean that you've only read one SM textbook or one textbook in any of physics?

user351417

16:42

@ACuriousMind How did you dig up something that's almost 3 years old?

Sir Cumference

@JohnRennie I was just joking about things like this

Jan 25 '17 at 18:14, by ACuriousMind

Well, asking why cheese heats up faster than the rest is a legitimate question, but the question should be framed properly. Remember, we hate fun here!

:P

John Rennie

@SirCumference then we'll clean out the stars so you can go and do it ll over again :-)

Anonymous

Abcd

STAR ME!

CaptainAmerica16

@Abcd Starred.

danielunderwood

16:43

@Blue you've revealed yourself!

You can't hide the yellow stars

ACuriousMind

@danielunderwood One in all of physics. The only textbook I've mostly read is Quantization of Gauge Systems, and parts of Weinberg's QFT.

Anonymous

Keeping that screenshot to display to the future generations

ACuriousMind

Everything else I learned from lectures and papers

Sir Cumference

@danielunderwood A javascript user can :P

Just replace the elements with black stars

Anonymous

@danielunderwood That was intentional

Anonymous

16:44

:P

ACuriousMind

@danielunderwood That's...unfortunate phrasing :P

Nog Shine

Looks like a rain of stars here.

Anonymous

enumaris

@ACuriousMind "parts of" Weinberg's QFT...you poor poor soul

Anonymous

DAMN YOU DEVS!

danielunderwood

16:46

@ACuriousMind were your lectures quite good? I feel like I had to supplement most of mine with extra info

ACuriousMind

@enumaris Well, I knew QFT already, so there was no point in going through the things that already made sense to me

rob

Stars Fell on Alabama

"Stars Fell on Alabama" is the title of a 1934 jazz standard composed by Frank Perkins with lyrics by Mitchell Parish. == History == One of the earliest recordings was by the Guy Lombardo orchestra, with his brother Carmen doing a vocal. This version was recorded on August 27, 1934, and issued by Decca Records as catalog number 104. The song was later performed by over 100 artists. Among them are: Al Bowlly, Bing Crosby (for his 1975 album A Southern Memoir), Lee Wiley, Ella Fitzgerald and Louis Armstrong; Cannonball Adderley with John Coltrane; Jack Teagarden; Jimmy Buffett; Billie Holiday; Anita...

Anonymous

Only 40 stars are not enough for THE GREAT STAR WARS!

enumaris

@ACuriousMind how's it feel reading an encyclopedia?

ACuriousMind

@danielunderwood Yes. Except for my electrodynamics and GR lectures I'd say all my lectures were excellent

(which may be a major part in why I much prefer QFT over GR :P)

enumaris

16:47

Blasphemy!

HISSSSSSSSS

Student404Mus

@ACuriousMind by the way, what is your grade ?

Abcd

Looks like everyone has used their vote allowance completely.

Anonymous

Does changing the system clock to tomorrow's date work? :P

Anonymous

Should try it

ACuriousMind

@Student404Mus The :<messageID> thingy has to stay at the beginning of a post, otherwise the ping doesn't work. If you just want to ping a user instead of replying to a message, just type @, followed by their username

Student404Mus

16:50

ok

and sorry if i'm asking you personal question you hate to be asked

danielunderwood

@ACuriousMind I don't suppose any of them are publicly available?

ACuriousMind

@danielunderwood Some of them are, e.g. Weigand's QFT and Weigand's String Theory

danielunderwood

woah. (S)he went all out on the lecture notes

Anonymous

Nah, SE keeps track on a central clock

ACuriousMind

16:53

@Student404Mus Ah, that was at me? I've got a MSc in Physics and am now a software developer

Anonymous

However, I can't edit messages after posting anymore

Anonymous

If I change the system clock

ACuriousMind

@Blue Well, you posted them more than 2 minutes ago! :P

Student404Mus

@ACuriousMind i see

Anonymous

hhbbdebnnjne

Student404Mus

16:53

@ACuriousMind youmean in general physics

Anonymous

@ACuriousMind Nah I can't even edit this ^

Anonymous

I mean, yeah, according to the system clock its more than 2 mins ago

danielunderwood

Does it let you edit if you turn your system clock back?

Anonymous

But if SE is using a central clock, that my last message should still be editable

ACuriousMind

@Student404Mus My specialization is theoretical physics, in particular QFT and string theory

Anonymous

16:54

@danielunderwood Yes

Student404Mus

@ACuriousMind good

what about standard model

enumaris

but which string theory? ( ͡° ͜ʖ ͡°)

danielunderwood

@Blue I figure it's probably using system clock to show you the edit button or not, but does a server-side check when an edit request goes through

ACuriousMind

@Student404Mus That's QFT, but theoretically it is pretty explored - most of the interesting bits about the Standard Model are either extensions or numerical work actually computing things.

@enumaris Huh?

enumaris

Aren't there many variants

Student404Mus

16:57

the story is tto long in standard model

enumaris

Is the answer always "whichever variants are not currently ruled out by the LHC"? :P

ACuriousMind

@enumaris "string theory" is exactly at the same level of generality as "QFT"

enumaris

So in QFT you can specialize to QED or QCD or Electroweak theory...you don't specialize in string theory to a specific aspect of it?

bolbteppa

You go even crazier in string theory :p

ACuriousMind

@enumaris the specializations tend to be a bit more general than in QFT since it doesn't pay to investigate specific models in depth as long as we don't know whether they correspond to anything real - some "specializations" off the top of my head would be model building, rigorous mathematical formulations, dualities

enumaris

17:01

hmmm

String theorists being rational? But I was told string theorists are all off in la-la land...

ACuriousMind

Of course there are more nuances: E.g. I know a (relative) lot about M-theory (=11d) supersymmetric model building, but little about 10d model building

John Rennie

@enumaris you've been reading Woit's blog too long :-)

enumaris

So why 11d?

@JohnRennie I might be...but just in case I don't...link?

Anonymous

@danielunderwood That sounds about right

John Rennie

@enumaris here

Anonymous

17:05

It shows "Just Now" for all the messages

Anonymous

if I shift the clock backwards

bolbteppa

physics sidenote bbc.co.uk/news/world-europe-45709205

unbelievable

ACuriousMind

@enumaris Because 11d is the highest dimension in which you can have a supergravity theory that has no particles with spin higher than 2, that theory is unique, and reducing it to 10d produces five unique different SUGRA theories - which in turn correspond to the five flavours of string theory.

John Rennie

@enumaris also see:

amazon.co.uk/Not-Even-Wrong-Continuing-Challenge-ebook/dp/…

ACuriousMind

So one suspects that there is a fundamental 11d theory that possesses the 11d SUGRA theory as its low energy limit, and the five string theories as its limits under dimensional reduction

bolbteppa

17:06

It's a supergravity argument not string theory per se

Anonymous

@bolbteppa wtf

ACuriousMind

Indeed, the uniqueness of the SUGRAs in high dimensions has nothing to do with string theory

John Rennie

@bolbteppa I'd be careful. We don't know what went on and there's no guarantee the BBC does either.

bolbteppa

@JohnRennie the slides to the whole thing are online, bbc was too kind to how nuts they were haha

enumaris

@ACuriousMind but why male models?

Sir Cumference

17:08

I love this response

ACuriousMind

@enumaris What?

bolbteppa

Today a woman won the nobel prize in physics for lasers and this guy...

enumaris

@ACuriousMind u never watched Zoolander?

ACuriousMind

@enumaris No

enumaris

I was debating whether to ask about 11d again or make a more explicit reference...

I guess neither reference would have gone through :(

bolbteppa

17:09

Mermannn

Zoolander is awesome

ACuriousMind

I don't watch a lot of movies. I find myself more drawn to the long-form storytelling of series

Anonymous

@ACuriousMind Ahem, ahem, Netflix/TV series?

enumaris

@ACuriousMind anyways, on a more serious notes, what are your thoughts w.r.t. Woit's not even wrong stuff?

ACuriousMind

@enumaris His critique is exactly as overblown as the promises of grandeur his opponents make :P

John Rennie

@enumaris theoretical physics can't be run like a factory. You have to get good people to work on what they want to work on.

Physics Meta

17:13

1

Q: Profile views, location section moved to extreme right corner

When I was going through some profiles on the site, I found out some different behaviour in a user's profile. Location, profile views section moved to extreme corner. Link to Akash.B profile However, It happens only for that user and not for other users. It looks normal for other users with lo...

bug profile-page

enumaris

hmmm

@JohnRennie debatable...if theoretical physicists had unlimited funding they might all be off in la-la land...

I know I would be :P

Anonymous

@PhysicsMeta @NogShine I was wondering about that too.

John Rennie

@enumaris there aren't that many theoretical physicists. It's a hard job. The amount of work and commitment involved matches any other job i can think of.

enumaris

I used to be one...ahh the good old days

when I was young

John Rennie

You're never going to have that many theoretical physicists, and the sum total of their salaries is never going to amount to more than a blip on global budgets.

ACuriousMind

17:16

@enumaris The border between physics and mathematics becomes rather fuzzy in theoretical physics anyway. Many of the vitriol thrown at string theory would equally apply to most of pure mathematics.

enumaris

@ACuriousMind nice deflection :P

Mathematicians be like "stop bothering me, I'm figuring out infinities"

John Rennie

@enumaris it's true though

Nog Shine

@Blue I checked many profiles but that happened for only one profile

Anonymous

@NogShine Indeed

John Rennie

No-one complained that Andrew Wiles wasn't worth his salary because all he did was prove some inconsequential statement about integers.

Anonymous

17:17

I haven't ever seen such a thing on SE

enumaris

@JohnRennie yeah, I'm only kidding, I certainly support people exploring what they want to explore :D

Nog Shine

@Blue Bugs everywhere

Anonymous

Probably some weird escape sequence in the profile description?

ACuriousMind

@enumaris It's not a deflection. I'm saying that if you question the worthwhileness of string theory you must be willing to apply the same criticism to mathematics. And art, for that matter. If you're going to be all "But where is the usefulness?" I expect you to be equally critical of all the other useless things humans do

enumaris

@JohnRennie surely there are some consequences of Fermat's last theorem? o.o

John Rennie

17:18

@enumaris as far as I know there are no industrial applications of Fermat's last theorem :-)

Anonymous

@enumaris None of them are "useful" as of now

enumaris

@ACuriousMind I'm gonna avoid the existential debate here...I was only talking tongue in cheek the whole time

Anonymous

(apart from in mathematics itself)

enumaris

My graduate thesis was on a theoretical aspect of neutrino physics that has never been observed experimentally...applied to situations that would never directly affect us...I have no base to critisize others there :P

ACuriousMind

@enumaris Ah, the old "Justify your life's work!" - ... - "Nah, I was only kidding, you don't have to.".

enumaris

17:20

Well, you'd have to justify COBOL

John Rennie

@enumaris My PhD was allegedly on science related to semiconductor fabrication, or at least that's what we told the funding body. We lied :-)

ACuriousMind

@enumaris About 75% of the entire world's transactions touch a system I'm ultimately involved with.

enumaris

(Maybe I should start adding in /s to my tongue in cheek posts...but they do comprise 95% of what I say here)

@ACuriousMind Sorry if I offended, I was not trying to be serious

Anonymous

@enumaris Tongue in cheek = /s ???

Anonymous

Which is the tongue and which is the cheek? :P

ACuriousMind

17:23

@Blue Either way, he should see a doctor about that

enumaris

Both tongues in both cheeks

ACuriousMind

@enumaris Oh, the COBOL thingy was perfectly clear irony - but before that you sounded like just another doubting Thomas about string theory ;P

enumaris

I know basically nothing about string theory so I am not at any level to critique it - I enjoy speculative theoretical physics as much as the next speculative theoretical physicist

Anonymous

Youtube comments are the best place to do that ;)

Anonymous

(One of my passtimes is pretending to be a crank on youtube)

enumaris

17:26

I mean, the fact that string theory gets a lot of criticism is a good thing in a way...at least it's "big" enough to get critisized lol.

all publicity is good publicity in a way? o.O

Emilio Pisanty

0

Q: What is Chirped Pulse Amplification, and why is it important enough to warrant a Nobel Prize?

The 2018 Nobel Prize in Physics has just been announced, with half going to Arthur Ashkin for his work on optical tweezers and half going to Gérard Mourou and Donna Strickland for developing a technique called "Chirped Pulse Amplification". While normally the Wikipedia page is a reasonable place ...

optics laser dispersion chirp

bam

there we go

c'mon, StackExchange, show me what you can do

Anonymous

@EmilioPisanty Woa, thanks

John Rennie

17:42

@EmilioPisanty now if there were any justice in the ~~world~~ HNQ ...

Emilio Pisanty

@JohnRennie that is indeed the goal for today

bring education to the masses

and fake internet points to my account

ACuriousMind

@EmilioPisanty I think you care more about the Legendary progress than the points ;)

John Rennie

My phone has just updated. I had hoped it was the upgrade to Android Pie, which is allegedly on the way, but no it's just the monthly security fixes. Boo.

Emilio Pisanty

@ACuriousMind a rep-cap day is still a form of fake internet point

Anonymous

@EmilioPisanty We sure do need more of these charitable endeavors more often to save PSE from getting lost in the pile of HW :)

Anonymous

17:46

I guess if anyone else answers it soon, it should go to the HNQ

John Rennie

@Blue I have attempted to interest Emilio in the question of what exactly a particle is, but he has so far resisted my attempts at seduction. I think that would make a great canonical Q/A.

Emilio Pisanty

@JohnRennie oh, god, that's well away from my wheelhouse

@Blue single-answer questions do make HNQ

Anonymous

@EmilioPisanty Ah, good to know. I haven't seen such an example myself tho

John Rennie

@EmilioPisanty I thought I remembered you saying it wasn't a very interesting question, but maybe I am mixing you up with someone else.

Emilio Pisanty

@Blue it just needs a high enough Q+A score in the first six hours

Anonymous

17:49

@JohnRennie Is there some background/history to that question which I missed? I'm not very sure what type of answers you expect for "what is a particle?"

Emilio Pisanty

@JohnRennie I do think it's interesting

Anonymous

Are we talking about the elementary particles?

Anonymous

(Standard Model)

Emilio Pisanty

I'm just not enough of an expert on QFT to put a good answer down

John Rennie

@Blue regular QM doesn't explain particles. It just says they exist.

QFT is the first time you get an explanation of what a particle really is, but the simplest explanation is that a particle is an excitation of a Fock state and that just looks like a plane wave - a momentum eigenstate.

Emilio Pisanty

17:52

@JohnRennie that last bit is wrong, though.

John Rennie

But electrons don't look like plane waves. They really do appear to be little blobs of ... something. So what corresponds to what we intuitively think of as particles?

Emilio Pisanty

there's plenty of non-plane-wave bases which are equally valid for that use.

John Rennie

@EmilioPisanty OK, based on the very little I know about QFT we work in momentum space and the Fock states are the momentum space version of simple harmonic oscillators.

Novalium Company

A quick question: A tesla coil (with alternating current throught it) does not kill a human because the voltage may be very high, but the current is very low. (conservation of energy, tranformers...). This tesla coil will produce a alternating magnetic field around it and when we bring a light bulb for example closer to the tesla coil, the alternating magnetic field will induce alternating current in the light bulb and that's why it lights up. Is this true?

John Rennie

So the states created by the creation operators look in real space like plane waves.

Emilio Pisanty

17:54

@JohnRennie we work in momentum space because it's convenient

but any other basis of Helmholtz eigenfunctions would work equally well

and the "simple harmonic oscillators" would be untouched

Anonymous

@JohnRennie I see, interesting

Emilio Pisanty

you could equally well work in a cylindrical-harmonics basis, with well-defined $p_z$ and $J_z$

Anonymous

That should be a great question, although I doubt how much I'd understand :P

Emilio Pisanty

or in a spherical basis, with well-defined $J^2$, $J_z$ and radial momentum

7

A: What is the orbital angular momentum (OAM) of individual photons?

This is an interesting mix of misconceptions: By definition, a photon is a one-particle state with definite momentum and helicity. In quantum mechanics, the OAM doesn't commute with momentum, and therefore a momentum eigenstate is not an OAM eigenstate. By that logic, individual photons canno...

^ see e.g. that

(though take the second answer with a huge grain of salt.)

Novalium Company

So in the end, in order for a tesla coil to not kill a human, the input supply power mustn't be high enough to kill a human, and from there, whether you'll use a transformer to level up the voltage and lower the current, it doesn't matter?

John Rennie

17:58

Ah, OK, thanks that's new to me.

After which amazing revelation (John doesn't know everything) I shall retire to my armchair to read a book and drink beer :-)

Transcript for