The h Bar

ACuriousMind

04:00

It makes sense, I just wouldn't really have expected it, but then again, I'm not sure what I expected

0celo7

not that mathy crap they call physics

DanielSank

@ACuriousMind :D

Yeah, it was an alternative approach. I'm rather proud of it though.

@0celo7 eh?

0celo7

@DanielSank I've never seen a vector

DanielSank

@0celo7 Some times, you say stuff that I just do not understand.

ACuriousMind

@DanielSank He's trolling :P

DanielSank

04:04

You mean vectors are an abstract notion?

0celo7

@ACuriousMind wtf!!?

I can't go one day in this place without being accused of some horrible crime

DanielSank

@0celo7 I think it's just that you have such a straight faced humor that it's hard to tell whether or not you're trolling.

ACuriousMind

@0celo7 You are obviously copying the pattern of "I've never seen X" from...someone.

DanielSank

I get what you mean about the vector now.

0celo7

@ACuriousMind Someone? I don't know who you're talking about Mr. Bajoran...

@DanielSank See, @ACuriousMind

ACuriousMind

04:06

@0celo7 You can't even tell how I figured out skillpatrol, and you think I don't see right through you? ;P

FenderLesPaul

@GBeau hold me

DanielSank

@0celo7 Bajoran?

0celo7

go write some equations, you know nothing about me

@ACuriousMind

DanielSank

^ Bajoran?

ACuriousMind

Yeah, I keep telling him they're a race in Trek

0celo7

04:07

jawohl, genau so sieht er aus

DanielSank

@0celo7 Wat?

ACuriousMind

But he insists my real name, which is Björn, sounds like that :P

DanielSank

@ACuriousMind What, he doesn't believe you?

@ACuriousMind Oh, heheh.

0celo7

it's obviously pronounced Bajoran

just look at it

DanielSank

@0celo7 Yeah, see, trolling.

FenderLesPaul

04:08

Bahoran?

DanielSank

Well, joking.

ACuriousMind

@0celo7 You tripled the number of syllables! That's not how it works!

DanielSank

@ACuriousMind re-watched Deep Space Nine recently. It's better than I remembered and it was already my favorite Star Trek series.

0celo7

I'm sure one day someone will bother to look at the chat log and see I didn't come up with that one...

DanielSank

Gee, how many syllables is that? One?

0celo7

04:09

but until then, continue calling me a troll

whatever floats your boats

ACuriousMind

@DanielSank I think I like it best, too, although TNG had its highlights. Have you seen its "rival", Babylon 5?

DanielSank

Hey, someone give me 400 rep so I can see the deleted posts in which I was accused of being a sock puppet master.

FenderLesPaul

@0celo7 dude

you're a troll though

like it's what you are

DanielSank

@ACuriousMind TNG is like putting on a warm blanket. Everything is always going to be ok. The characters almost never develop at all. I like DS9 because there's actually an arc. People's lives change significantly.

I have not seen Babylon 5.

0celo7

@FenderLesPaul wow

DanielSank

04:11

I saw the revived Battlestar Galactica, and loved the first ~2 seasons. After that, man it got bad.

0celo7

that's the most horrible thing anyone's ever said to me

ACuriousMind

@0celo7 That Kyle came up with it doesn't mean you have to keep using it

DanielSank

@0celo7 Ahhh just ignore him.

0celo7

@ACuriousMind did you know that or have to check the log

ACuriousMind

@DanielSank If you like the...arciness of DS9, B5 is for you

DanielSank

04:12

@ACuriousMind Ok cool!

ACuriousMind

Maybe don't watch the last season

DanielSank

Battlestar tried to have arciness. Some of them worked, but most of them were so stupid I wanted to scoop out my eyeballs.

ACuriousMind

It was added after the arcs had been hurriedly concluded in the season before because they thought it was going to be the last.

DanielSank

I mean, the first two or three seasons were excellent.

I noticed something really funny about Battlestar. Check this out:

FenderLesPaul

@0celo7 sorry

I lashed out

in anger

DanielSank

04:13

In the opening credit sequence, at the end, there's a title screen that says:

FenderLesPaul

I didn't mean that

DanielSank

"The cyclons are coming"
"and they have a plan"

Or something like that.

0celo7

@DanielSank so how would you pronouce Bjoereoean

DanielSank

I noticed that in the last couple seasons they removed the "they have a plan" part.

LOL

ACuriousMind

lol, although I've not watched it

DanielSank

04:14

I think this was a reflection on the writers realizing they had no plan.

The show just got so unbelievably weird and stupid.

It was a lot like LOST.

ACuriousMind

@DanielSank that would be suspiciously...planned for people without a plan, wouldn't it?

@DanielSank Oh god don't remind me

I'm still angry about that ending

DanielSank

After a while, characters started doing uncharacteristic and plain foolish stuff just as a plot device.

@ACuriousMind I gave up on LOST after three seasons.

I watched Battlestar through because my friend was watching it with me and said it was great.

ACuriousMind

@DanielSank In retrospect, correct decision

DanielSank

@ACuriousMind Right. I saw what was happening. They had so plan at all for that show. It did the one greatest sin of storytelling, in my opinion.

ACuriousMind

Although I really hoped they weren't lying through their teeth when they said they had it all planned out

Turns out they were

DanielSank

04:16

When a character makes a decision which is both out of character and stupid, just to insert conflict into a story, I become enraged and stop paying attention.

ACuriousMind

@DanielSank It's called Idiot Ball (caution, TVTropes link)

DanielSank

Thanks!

I've been calling that the "great sin of storytelling". Now I have a catchier term and a link!

I really hate that.

Very much. It makes a story immediately terrible.

Dumbness is ok if the character is dumb. So is making mistakes, but some times characters just randomly decided to do unbelievably (as in, I don't believe the character would do that) stupid things.

LOST was a lesson in Idiot Ball story telling.

"Oh wow, we're all about to figure this stuff out and get along. I know! I'll freak out and shoot someone for no reason!"

ACuriousMind

Yeah, it's kinda sad

DanielSank

Honestly, I haven't been impressed with anything Abrams has done yet.

The first Star Trek reboot was ok.

The second one was so bad it hurt.

ACuriousMind

I don't like the reboot at all, it doesn't fell like Star Trek

0celo7

04:23

You watch SW7?

ACuriousMind

@0celo7 Yes. A bit unoriginal, but I liked it

DanielSank

@ACuriousMind It's definitely different, but I'm ok with that to some degree. I mean, each series feels different too. I don't like that Abrams (or the writers, I guess) inserts action scenes which do not serve the plot at all.

@0celo7 Yes. I liked aspects of it. I'm mostly just glad it wasn't completely horrible.

Rian Johnson is writing and directing the next one. I expect it to be much better.

ACuriousMind

What else did he do?

DanielSank

Brick

If you haven't watched this, certainly do so.

Looper

Those two are both rather good. Brick is truly excellent.

ACuriousMind

Never heard of Brick, heard mixed things about Looper

DanielSank

04:28

Brick is, in my opinion, truly a work of original art.

It's a film noir, set in a high school.

That doesn't sound compelling, does it? Yet it's a really awesome movie.

ACuriousMind

@DanielSank Have you watched Veronica Mars?

DanielSank

@ACuriousMind Nope. What's that?

0celo7

I have some girl's shorts in my laundry -- weird

DanielSank

@0celo7 Ahahahahahahaha not weird in college, my friend.

Good job.

0celo7

they're not from the girl I'm going out with @DanielSank

DanielSank

04:37

ಠ_ಠ

0celo7

note the weird

ACuriousMind

@DanielSank The description "sort of a film noir in a high school" is also applied to that. The titular character is a highschool girl working as a private eye

0celo7

I do not know how these got here

sounds like the Zodiac PI manga

DanielSank

@ACuriousMind Is it good? I should watch?

ACuriousMind

@DanielSank It's quite good, imo, and the longer story arcs are very well set up. How noir it is varies wildly between episodes, though

DanielSank

04:41

@ACuriousMind Oh it's a show. Where to get?

ACuriousMind

@DanielSank Don't know, I borrowed the DVDs from a friend to watch it.

DanielSank

@ACuriousMind Ok. I'll look around.

It's on Amazon.

groovy

ACuriousMind

Now to go look for Brick...

FenderLesPaul

fucking love cinnamon toast crunch

ACuriousMind

1

Q: Detection of radioactive iodine at trash dumps

I have a cat that is getting radioactive iodine therapy and I am told I must flush the litter for 2 weeks because if I throw it away normally the dump will detect the radiation and fine me. This seems pretty crazy to me. My understanding is that to detect the radioactivity from the cat you liter...

lol

The HNQ-worthy title would of course be: "Will I get fined for my cat's radioactive feces?"

2

ws04

05:08

hello

can someone help me understand something

:S

Secret

05:22

@DanielSank I have yet to watch the movie, but I remember back in 2013 I have used various plot synopsis (2nary sources) and piece together a timeline for Looper, and I basically end up with a 4 dimensional object

Looper is basically a major inspiration of that time travel model I mentioned some time ago, which is responsible for some of the CTC questions I asked Slereah in the chat around a year ago

@ws04 what specifically?

Secret

Looks like an airport
Still trying to figure out how to reduce the number of dimensions, though

ws04

05:45

i was just about to ask a question about it, but i guess if you can answer it first

I understand that there are proofs (e.g. [proof][1], [another proof][2]) of why the angular momentum about two points for an object is the same. However, can you give an intuitive explanation of why this is? I work far better with something I can visualize than with variables and formulae.

[1]: http://physics.stackexchange.com/questions/102453/find-angular-momentum-about-any-point
[2]: http://physics.stackexchange.com/questions/71761/independancy-of-angular-momentum-with-respect-to-origin-for-rotation-about-cente

@Secret

ws04

06:04

..

Secret

06:20

Qmechanic

09:49

0

Q: Electrometer mode of universal amplifier

Explain why a high resistance is used in electrometer mode. A voltmeter can also be connected to amplifier but what is the use of high resistance in universal amplifier electrometer mode. The circuit is

electric-circuits resistance capacitance electronics

Would Electrical Engineering be a better home for this question? Reading the comments it seems more about the amplifier than the measurement.

yuggib

@0celo7 arxiv.org/abs/1601.06467

@0celo7 this should be the analysis of PDEs that you like...

@Qmechanic I agree

GBeau

10:43

@FenderLesPaul In an attempt to find things to stop me thinking about applications, I found the rapper BoB on Twitter attempting to use LaTeX to prove the earth is flat: twitter.com/bobatl/status/691725988586061825

privetDruzia

10:55

Hello @GBeau

:)

GBeau

@FenderLesPaul Purdue, rochester, NC state

GBeau

11:28

@FenderLesPaul on schedule, UCSD today

0celo7

12:17

@yuggib Unfortunately I don't see how that raises the GDP

yuggib

13:37

@0celo7 It raises your brain GDP

0celo7

@yuggib that's not a real thing

yuggib

says you...the "standard" GDP instead is really tangible

0celo7

yes

I have seen it in the night sky

yuggib

in this moment, it would be more frequently seen laying low

than sky high

anyways, happy with the s'bowl teams?

0celo7

I don't particularly care about either team

my dad is a Broncos fan due to Peyton Manning

yuggib

13:46

the crawfish shorts guy

T__T

0celo7

yes

yuggib

(btw I know quite well who he is...)

0celo7

you obviously pay attention to his beach photos

yuggib

no, just to commercials that they give during timeouts in football matches

0celo7

what

oh I thought you were talking about his beach photos

(at work, distracted)

yuggib

14:01

no, about a commercial

tvcommercialspots.com/insurance-and-services/…

0celo7

14:28

@yuggib oh, I have seen that commercial

@yuggib is all PDE stuff this ridiculous

Secret

In the last 2 weeks I have been browsing web of science for articles, by diving through the entire citation maps, reading 5000+ titles to finally find the 200+ articles I needed for literature review

yuggib

14:45

@0celo7 :-D not at all...only the PDEs involving general relativity

and geometry

0celo7

those are the interesting ones :(

yuggib

for you maybe, for me $i\partial_t u = -\Delta u +\lvert u\rvert^{p-1}u$ is more interesting

0celo7

@yuggib why were you looking at gr-qc?

yuggib

list of unknowns: $u$

0celo7

seems pretty boring

yuggib

14:47

@0celo7 I was looking at my usual two arXiv entries: math.ph and math.ap

0celo7

just integrate

yuggib

actually the aforementioned paper is tagged in both

0celo7

math.ap?

yuggib

analysis of pdes

every week day, first thing in the morning, open arXiv and check math-ph and math.ap

that's how I was taught

0celo7

why

quantum algebra is a thing?

yuggib

14:54

@0celo7 algebras of operators are a thing important in quantum physics

0celo7

@ACuriousMind what is "void swelling" in crystals?

ACuriousMind

@0celo7 How the heck am I supposed to know?

0celo7

@ACuriousMind Uh, because you know everything?

yuggib

@0celo7 but I don't know if quantum algebra exists as a name

there is quantum logic

quantum set theory

guest

What defines something as an "algebra"?

Like Boolean algebra, linear algebra, abstract algebra,...

0celo7

15:03

@yuggib there's an arxiv section for it...

ACuriousMind

Mathematicians have started to use "quantum" as a word for "deformed" in some sense. I'm not sure how much their "quantum" things still have to do with our quantum things

0celo7

@guest An algebra is a well defined concept, namely a vector space with a bilinear product.

2

e.g. Lie algebra, tensor algebra

I'm impressed by my RAM hogging skills

ACuriousMind

@0celo7 Well...an algebraist will say it's a module with a muliplication operation in it, or equivalently a ring which is also a module over another ring.

0celo7

@ACuriousMind Ok, that's the same thing but with vector space --> module.

Don't know why it was starred twice, but OK.

FenderLesPaul

@GBeau no ucsb yet

then again it's 7am in Cali

0celo7

15:21

oh wow an experimental paper in LaTeX

my eyes are saved

$$2A_2O_3+2B_B^\times+O_O^\times\to 2A_B'+V_O^{\bullet\bullet}+A_2B_2O_7$$

looks like some group theory crap

guest

No Cal Tech? @FenderLesPaul

David Z

15:45

Anyone else having trouble with gravatar?

ACuriousMind

What kind of trouble?

David Z

The HTTP requests taking a long time - upwards of a minute

of course now that I type that they work. Weird.

guest

"of course" :D

Why did stack exchange stop using Gravatars anyway?

FenderLesPaul

@guest caltech hasn't sent anything out yet

0celo7

16:03

I may or may not have PDE class today, the prof has jury duty

@yuggib Imagine how nonrigorous one of his grad students would be D:

Or maybe he gets some functional analyst to teach today and we get some "real" math

David Z

Oh, hey, time for a chat session!

I will say, this chat session time is decidedly less convenient from China

0celo7

I'm in class during chat sessions.

We should talk about solid state physics for once.

Specifically radiation damage in complex oxides. More specifically, pyrochlore.

David Z

Sure, why not

I don't know anything about it though

0celo7

I don't either. The opening paragraph for this paper I've been assigned has 11 references for background.

I'm going to have to go paper hunting.

David Z

Before we get too far into it, I do want to remind everyone of the ongoing effort to restructure the homework policy. I don't really have anything new to say about the matter today, though.

12

Q: Generalizing the homework policy

In our last chat session two weeks ago (sorry for the delay), we had a discussion about updating the homework policy and homework close reason. I'm making this post to summarize that discussion and solicit feedback on how to proceed afterwards. The current status According to the homework polic...

discussion featured scope homework

0celo7

16:10

@DavidZ I'm kidding, prof just walked in. Bye.

0537

@0celo7 <3

David Z

haha, ok

yuggib

@0celo7 Don't let me think about it

but in engineering/numerics it's ok to be non-rigorous

ws04

(wat is dis)

David Z

hi @no_choice99

no_choice99

16:15

hey there

can someone help me to understand the comment to my answer at physics.stackexchange.com/questions/231809/… ?

David Z

We are having a chat session but nobody seems to have anything to chat about :-P

oh that works

no_choice99

did the guy make a joke or just said non sensical stuff?

David Z

Thank you! May your paper milk containers always fold smoothly and without tearing! — user47989 10 hours ago

ACuriousMind

@no_choice99 I'm going to go for "joke"

no_choice99

yeah . I'm not good in English so I may miss the joke

but i don't see what's the relation between my answer and this joke

ACuriousMind

16:16

I'm not sure why I should care whether my milk contianers tear or not

@no_choice99 I think it's just meant to be something like "Best wishes", it doesn't relate to the answer.

David Z

Yeah... I think it's a cultural thing. Paper milk containers have a reputation (an entirely undeserved one, IMO) for being difficult to open, and often spilling much of the milk inside when you try to open them.

no_choice99

ok thanks

David Z

So anyway. Let me fall back on some defaults I guess: who's here? Anyone in their first chat session? Or new to the site?

yuggib

useless physics:

physics.aps.org/articles/v9/4

choreographic crystals

Secret

might be useful to describe some collective motion of bacteria when confined, because another article said they kinda act like electrons

yuggib

16:25

should not PRL be a top notch journal?

David Z

PRL is a top journal

yuggib

publishing choreographic crystals

Secret

news.mit.edu/2016/shared-behavior-microbes-electrons-0105

2

David Z

Arguably the most prestigious in physics (well, definitely in HEP at least)

yuggib

@DavidZ yeah, I thought it so

hardly publishes purely theoretical stuff though

FenderLesPaul

16:31

@yuggib I don't think there's a single journal that is really well reputed for HEPth

I think most people just check on the arxiv

There used to be a well reputed one for GR but nowadays I don't think it's used as much for GR

ACuriousMind

@yuggib I remind you of the quantum $\pi$ :P

David Z

It's a minority, but I think PRL does publish some pure theory

I rarely look up those papers though so I don't keep track

yuggib

@FenderLesPaul I thought JHEP was not bad

@ACuriousMind I was obviously thinking the same

it seems that if you write some nice-looking but probably useless stuff you can get published on very reputed journals

FenderLesPaul

Isn't most theory research nice-looking but useless stuff?

at least HEP and GR are

vzn

@Secret interesting, cool, thx for sharing! reminds me of spin glasses! (wonder if there is some connection... it mentions phase transitions.)

FenderLesPaul

16:35

CMT is definitely on the more useful side

David Z

@yuggib ahh, yeah, a lot of hep-th stuff does appear in JHEP

FenderLesPaul

@DavidZ did you do pheno at Penn State?

yuggib

@FenderLesPaul maybe some day you could need worldline quantum mechanics on a Kähler background manifold...who knows

David Z

Yep

FenderLesPaul

Cool

David Z

16:38

assuming by pheno you mean particle phenomenology

FenderLesPaul

yeah

yuggib

what do you study on particle phenomenology?

David Z

I work on small-x parton distributions and saturation physics - or if you don't know what that means, it's basically the effective structure of atomic nuclei and protons in certain kinds of high-energy collisions

vzn

@DavidZ do you do simulations? or work with computer models etc?

David Z

ugh my chat interface is going crazy due to slow internet

@vzn no, not really. I write programs that calculate integrals, but it wouldn't seem right to say I'm simulating anything.

vzn

16:42

@DavidZ what language? do you use other software pkgs eg statistics analysis etc?

David Z

It's a lot more like data analysis than simulation

FenderLesPaul

So are you doing a post-doc right now?

David Z

@FenderLesPaul yeah

Well, the main program is in C++ and C, the analysis scripts are in Python, the batch submission system is a Python/bash hybrid... the list goes on

FenderLesPaul

Dope

David Z

haha :-P

It's stressful, actually

FenderLesPaul

16:46

Yeah it seems to be quite an emotional and mental toll

I don't know how people manage that stuff and still publish papers

yuggib

@FenderLesPaul if you don't publish, you will stop doing postdocs soon

FenderLesPaul

and still manage to take care of finances

yuggib

and not because you will get a permanent position :-P

FenderLesPaul

:p

David Z

If you're publishing papers, that makes it easier, I think. Roughly, the more you publish (given that it's all good), the better you're doing at your postdoc.

So people who publish less probably have more stress

FenderLesPaul

16:47

Is that also true for grad school?

yuggib

It's a dog biting its tail

David Z

@FenderLesPaul Not quite so much

yuggib

no, grad school is more relaxed

FenderLesPaul

I know a couple of people in their 4th/5th year and have only published 1 or 2 papers

while I know 3rd years who have published like 5 or 6

and the latter are definitely less stressed :D

yuggib

btw, grad school in Europe is just 3 years in most of the countries

David Z

16:48

I've known people who have graduated without ever having published - of course in their field, that's normal (and they have a few in the works)

FenderLesPaul

I see

no_choice99

yeah but in europe you do a bachelor and then a masters before phd right?

vzn

@yuggib very cool blog by DZ on his research, cited/ commented before here, prob too shy or modest to cite it ellipsix.net/blog/2015/01/about-saturation.html

yuggib

@no_choice99 yep

0celo7

@FenderLesPaul how many pubs do you have

no_choice99

16:49

so phd in europe is 5 years (bachelor + masters) and then 3 years phd

FenderLesPaul

@0celo7 I'll have 2 by the time I graduate (they're in the draft phase)

yuggib

exactly

David Z

Oh yeah, somewhat relevant :-) That's part 2 of a 3-part series which I intend to finish someday

@FenderLesPaul wait, are you an undergrad? Or master's level?

FenderLesPaul

@DavidZ undergrad

vzn

@FenderLesPaul what topics?

yuggib

16:52

@FenderLesPaul 2 papers at the end of undergrad is unusual

FenderLesPaul

@vzn one is on black hole supertranslations and the other is on causality constraints in QFTs from a position space point of view

yuggib

let me formulate better: two published papers at the end of undergrad is unusual

David Z

Yeah you're way ahead of the "curve"

no_choice99

i think fender started college already knowing a lot of GR

vzn

@yuggib eg "published" at arxiv?

yuggib

16:53

no, peer-reviewed published

everyone can put stuff on the arXiv

it does not mean anything

David Z

Although even having two things posted on arXiv at the end of your undergrad career would be unusual

Anyone can post there but you do have to be endorsed

yuggib

with a peer review process, despite its many drawbacks, at least there is some guarantee of originality and correctness

no_choice99

specialists shouldn't have a hard time figuring out whether the paper is high or low quality anyway

yuggib

@DavidZ yes, true

FenderLesPaul

These aren't by myself or anything

they're with the professors I work for

David Z

16:55

Yeah, we know

yuggib

It's unusual anyways

Terry Bollinger

@DavidZ I did not know the term "parton" was still used much...

David Z

It's a niche field, but yeah, we use it all the time

vzn

@yuggib agreed, peer review is (imperfect) scientific quality control. curious what are you working on?

David Z

Unfortunately it seems to have several different meanings depending on context, and it's almost impossible to tell which one is intended

yuggib

16:57

@vzn I am a mathematician

Terry Bollinger

@DavidZ Parton, you mean? how does it differ from just saying "quark" in your work?

yuggib

I work on semiclassical analysis in infinite dimensions, with applications to QFT

David Z

Gluons are partons too

yuggib

that is the big part, also some non-linears PDEs and stuff

Terry Bollinger

@DavidZ !! did not know that...!

David Z

16:58

That is, one meaning of "parton" is either a quark or a gluon (or I think it can also incorporate electrons, photons, etc. but the corresponding wavefunctions are negligible)

That's the meaning that appears in e.g. "parton distribution function"

vzn

DZ your work reminds me of the philosophy of reductionism & its possible limitations. see eg metanexus.net/essay/… (just googled that. wonder if anyone in physics has written anything similar)

Terry Bollinger

@DavidZ so it's become sort of a catch-all term for anything with a non-zero amplitude in a nucleon?

David Z

But there's also something called the parton model, which I think is meant to imply that the constituents of the proton are literal particles rather than quantum fields? Maybe? I have a hard time remembering. But it's something a little different from just "a quark or gluon"

@TerryBollinger yeah, pretty much

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