The h Bar

John Rennie

16:00

@0ßelö7 I don't often delete messages. When I do find myself moved to delete them it's because I believe they shouldn't have been posted, and if I believe a message shouldn't have been posted then I will delete it and damn the torpedoes.

Semiclassical

oh, with regard to entanglements of distinct particles: spectrum.ieee.org/tech-talk/semiconductors/devices/…

so that's a pretty practical example of electron-photon entanglement

It's interesting that the experiment given there is both fairly recent (2012) and uses a somewhat esoteric system (quantum dot). So it's not a trivial accomplishment by any means. @ACuriousMind

0ßelö7

@JohnRennie Hm.

GPhys

16:28

looking at QFT homework

Anonymous

#include <stdio.h>
int main()
{
char str[100], search[100];
printf("Enter a string ");
scanf("%[^\n]s",str);
printf("\n Enter search substring ");
scanf("%[^\n]s",search);
}



When I run the above code, the first `scanf()` does execute and takes user input. However, it skips over the second `scanf()` and ends the program.

I think this happens because the second `scanf()` finds `\n` in the buffer (from previous input) and stops. What can I do to correct this behaviour?

Anonymous

@JohnRennie Could you help with that ? ^

vzn

@0ßelö7 do you really care or are you just mocking the topic? (often quite a fine line for you anyway... but ps thx for the defense) :( :|

@Semiclassical its some cutting edge stuff to try to get quantum computing going in silicon chips. entanglement is one of the core mysteries of QM. however there is some... sensitivity to openly/ freely discussing the topic among hardcore physicists...

ACuriousMind

@Semiclassical Nice, so it exists practically, but is kinda hard as I guessed

Emilio Pisanty

@DanielSank frankly, I'm confused about what that question is asking

John Rennie

16:40

@Blue give me a mo and I'll fire up my C compiler ...

Anonymous

Sure. Take a mo :P

Semiclassical

@ACuriousMind yeah

what i was mainly interested was which interaction was giving rise to the entanglement

with electron-electron pairs, it's the Pauli principle i.e. the fact that the electrons are quantized excitations of a fermionic field

with that experiment, you're able to get entangled electron-photon pairs but that's evidently by virtue of the system you're working with

I'm not sure what conclusion, if any, one can draw from that though.

John Rennie

@Blue I agree it's because you're telling scanf to read up to the first \n, so it stops leaving the \n in the input buffer.

Anonymous

@JohnRennie Right! I need to do something so that the \n is consumed

John Rennie

The ideal solution would be to flush the input buffer, but there is no way to do this in C.

Anonymous

16:48

Sounds bad....any alternative? Would gets() work?

John Rennie

There are various solutions, of which the best is not to use scanf, which is the work of the devil anyway.

gets() works but is deprecated because it suffers a buffer overflow vulnerability.

getline() is better

Anonymous

@JohnRennie What does that mean?

Anonymous

@JohnRennie Trying that...

John Rennie

Or use fgets()

@Blue Your array str is 100 bytes long. Suppose I type an input string longer than 100 characters. The program will still read it into memory starting at *str so it will overflow the end of the array and corrupt memory.

0ßelö7

@ACuriousMind the professor claims it's true without any hypotheses on the curves

he said to ask Morwen about it

@vzn both

John Rennie

16:51

@Blue The scanf function has no way of checking for buffer overflows because it doesn't know how big your array str is.

0ßelö7

I would hope that by now you know that unless it's analysis or geometry, I am always mocking it at least a little bit

John Rennie

@Blue the getline function checks the length of the data input and allocates a buffer big enough so there cannot be an overlow. The only catch is you need to remember to free the pointer returned by getline.

vzn

@0ßelö7 maybe you should ask Einstein what he thinks o_O

0ßelö7

@vzn my cat can't talk

John Rennie

@Blue The fgets function has an argument that tells it how big the buffer is, so again a buffer overflow isn't possible.

Anonymous

16:54

@JohnRennie I get it. Thanks. I'm trying to change my program using getline/fgets

Anonymous

@JohnRennie I found a quick and dirty fix. Lol. Declare a character variablechar ch and then scanf("%c",&ch) after the first scanf() to consume the newline character.

John Rennie

@Blue If I were your examiner you'd get zero marks for that trick.

Anonymous

But yes, the overflow issue is still there...

0ßelö7

@JohnRennie what does that mean?

good or bad?

Anonymous

So I'll use getline or fgets now

Anonymous

17:00

:P

John Rennie

@0ßelö7 Bad. Ignoring possible buffer overflows is unacceptable coding.

@Blue with fgets you need to check whether the input was too long for your buffer. With getline() you don't have to check.

In both cases the input includes the '\n' and it's up to you to trim it off.

vzn

@0ßelö7 guess one mans sacred cow is anothers BS

Emilio Pisanty

0

Q: How many significant figures should one give in stating a experimental uncertainty?

How many significant figures should one give in stating a experimental uncertainty? For this purpose I found three rules: Experimental uncertainties should be always stated to 1 significant figure. For example: $3.45 \pm 0.015$ should be $3.45 \pm 0.02$ [doc1]. The number of significant...

^ surely this is a dupe, right?

vzn

17:19

in theory salon, 2 mins ago, by vzn

A blueprint for demonstrating quantum supremacy with superconducting qubits / Neill et al (Google-Martinis lab)

Gravity may be created by strange flashes in the quantum realm / new scientist

Anonymous

@JohnRennie Okay, fgets is working. But one problem with fgets() is that it includes a newline character. I again need to do something to get rid of that newline character before printing.

Anonymous

Take this for example:

Anonymous

#include <stdio.h>
int main()
{
char name[10];
printf("What's your name? ");
fgets(name,10,stdin);
printf("\n Glad to meet you %s.",name);
return(0);
}

Anonymous

The full stop appears in the next line (for the output given by printf)

Anonymous

Say, you input "John" for this program. The output appears as: Glad to meet you John

Anonymous

17:25

.

Anonymous

Anything after %s appears in the next line

0ßelö7

@JohnRennie is there a way to bind a full-size period table to a button on my keyboard? Like if I press "page up" (which I never use), can a period table show up?

Anonymous

@0ßelö7 What is "period table"?

Anonymous

You mean the chem one?

0ßelö7

sure

I have no idea how I missed the -ic twice

Anonymous

17:28

I think there are plenty of key remapping softwares out there on the net

Anonymous

You need to look for the right one

0ßelö7

but how do I get a periodic table to pop up

Bernardo Meurer

Heyo

Anonymous

@0ßelö7 Save it as an image on your Desktop. When you press that key, the image should open.

Anonymous

via "Photos" or some app like that

Anonymous

17:30

Or just change your Desktop background to a Periodic Table...lol

0ßelö7

@Blue gross

Anonymous

0ßelö7

tiny image

Anonymous

Doesn't look that bad

0ßelö7

periodic table for ants

Anonymous

17:32

You'll get HD quality ones on the net

Bernardo Meurer

@Blue Sorry I haven't been around lately to help you with C :(

Anonymous

@BernardoMeurer It's okay. JR helped me out. How's life in California going on?

Bernardo Meurer

It's alright, I'm having a good time

Anonymous

Great :)

Anonymous

I just received my Arduino Uno today morning...pretty excited :D

Bernardo Meurer

17:36

@Qmechanic You like them too?! Dope!

@Blue Awesome!

Arduinos are GREAT for learning C IMO

no MMU means you actually get to see your bugs happen

So if you screw up a buffer access or allocation it'll compile and run

and then your circuit wil go naynays

I have video, one second

John Rennie

for (i = 0; str[i] != '\n' && str[i] != '\0; i++);
str[i] = '\0';

Bernardo Meurer

Weird C Bug

►

e.g.

@JohnRennie Isn't there something in the stdlib for doing that?

John Rennie

@BernardoMeurer is there?

Anonymous

@BernardoMeurer Haha...sounds like lot of hear tearing is upcoming for me :'D

0ßelö7

"The reason why macs are so expensive compared to pcs is because apple use quality materials not plastic and they also have a lot more technology inside" :^)

Bernardo Meurer

17:39

@JohnRennie There's everything somewhere in there

Anonymous

@JohnRennie Ah, loop will obviously work. :D

Anonymous

@0ßelö7 Meh.

John Rennie

@0ßelö7 Save the image of the periodic table somewhere, then create a shortcut to it on your desktop. Right click the shortcut and choose Properties, then you can set a hotkey for the shortcut. Now when you press the hotkey the image of the periodic table will open.

Bernardo Meurer

@JohnRennie Aha! I know how to do it!

strtok(var, "\n");

E L E G A N C E

John Rennie

@0ßelö7 it's because Macs are lifestyle choices i.e. fashion accessories!

Bernardo Meurer

17:44

Macs look great, feel great, and work well enough, I don't see why people go naynays over this

John Rennie

@BernardoMeurer and that's faster than my method? :-)

0ßelö7

@JohnRennie I think only people who don't use macs think that

What kind of fashion statement is it supposed to be?

Bernardo Meurer

It's perfectly fine to pay more for something that is beautiful

0ßelö7

It's PC people who think that

Bernardo Meurer

Also, it's OS is POSIX but still has loads of software

0ßelö7

17:45

Makes me think it's jealousy

Bernardo Meurer

I think it's a fair choice for a computer

John Rennie

@BernardoMeurer that's pretty much the definition of a fashion accessory

0ßelö7

@BernardoMeurer is reasonable

Bernardo Meurer

@JohnRennie Not sure, but it sure looks better :P

0ßelö7

@JohnRennie wrong

Bernardo Meurer

17:45

I'd benchmark but I'm lazy

Mithrandir24601

@Blue I was one of the earlier ones to get a raspberry pie just before I started my CS degree :P

John Rennie

@0ßelö7 I have two Mac Minis. I bought them because at the time they were the perfect solution to a problem I had.

In fact they still are, and I still use them.

0ßelö7

so you're a traitor

John Rennie

@0ßelö7 I am an arch pragmatist. I will use whatever works best.

I don't care who made it.

0ßelö7

the worst of the traitors

Anonymous

17:47

@Mithrandir24601 Same here. Just replace RPi with Arduino. :P

Bernardo Meurer

@JohnRennie So, I'm looking at this code I wrote a while ago

Anonymous

And "earlier" with "earliest"

Bernardo Meurer

That is an iterative implementation of Ackermans function

John Rennie

Yes?

Bernardo Meurer

and I have no clue how on earth this works

Halp

github.com/bemeurer/multi-ackermann

0ßelö7

17:48

did you not comment the code?

Bernardo Meurer

No, I was a scrub

Mithrandir24601

@BernardoMeurer but it's better to pay the same and get a super-good gaming laptop :)

0ßelö7

people who have expensive gaming laptops are the worst

they are invariably insufferable

Bernardo Meurer

@Mithrandir24601 What if I don't want a gaming laptop? They look super cringy, their battery doesn't last, and they're heavy

0ßelö7

all gaming stuff looks super cringey

Mithrandir24601

17:49

@Blue Welcome to the wonderful (and well-paid!) world of CS!

Anonymous

@Mithrandir24601 Nah...I'm not interested in software jobs :P But yeah, I do like CS

Mithrandir24601

@BernardoMeurer erm... The battery does last, just not when gaming...

Anonymous

I'm more interested in algorithms than programming(web development etc.) though

Bernardo Meurer

@Blue @JohnRennie @dmckee @Mithrandir24601 A keg of beer to whoever figures out how my Ackermann implementation works!

John Rennie

To be fair I can see the point of a gaming laptop. It's effectively a portable workstation though.

0ßelö7

17:50

@JohnRennie the only nice thing about Windows is the ability to have programs snap to 1/2 or 1/4 of the page

Bernardo Meurer

@0ßelö7 Gnome has that :P

0ßelö7

@BernardoMeurer yup

Mithrandir24601

@Blue same, although I'm now doing something slightly different and even better :)

John Rennie

@0ßelö7 This focus on cosmetic niceties is an alien mindset to me.

0ßelö7

hence why I am finding myself working on Linux now because it does exactly what it needs to do

Mithrandir24601

17:51

@JohnRennie It's absolutely fantastic

0ßelö7

If you're so addicted to video games that you need them on a laptop, seek help.

John Rennie

@Mithrandir24601 I take it you've bought a gaming laptop? :-)

Bernardo Meurer

I'd like one of those Dell workstation laptops

They double as a self defense weapon and bulletproof vest

Really useful

0ßelö7

get the Razer triple monitor laptop

Bernardo Meurer

Lol, no way

0ßelö7

17:53

doubles as a brick for weighing down a body you dump in the river

John Rennie

I could be tempted by one of these

Though of course only for running finite element stuff on the GTX1080 :-)

Bernardo Meurer

@JohnRennie I almost bought a dell rack server yesterday

Luckily I had less money than I thought I did

John Rennie

@BernardoMeurer Which one?

0ßelö7

@BernardoMeurer with what money

@JohnRennie you can have my 1080

Bernardo Meurer

losangeles.craigslist.org/sfv/sys/d/dell-poweredge-r710/…

0ßelö7

17:55

I don't use it and it's not like anything is optimized for it

Bernardo Meurer

Almost did it

John Rennie

@BernardoMeurer that would be noisy as hell and guzzle power like it was going out of fashion.

0ßelö7

why doesn't AFT come to chat anymore?

Bernardo Meurer

@JohnRennie Exactly

EXCITEMENT

It IDLES at 300W

lol

0ßelö7

@BernardoMeurer get an etherium mining rig

John Rennie

17:56

I think you'd find the excitement wears off :-)

Quickly!

0ßelö7

and a small nuclear reactor to power it

@JohnRennie I get free power in my apartment. Wonder if I'd get in trouble if I ran a server out of it.

well, "free"

I don't pay extra for utilities

John Rennie

Your PC probably uses over 100W at idle.

0ßelö7

@JohnRennie At full blast I blow a fuse if the ceiling fan is on :)

John Rennie

Just don't tell the landlord :-)

0ßelö7

it's the university, I could probably get in trouble for a lot of things here

John Rennie

17:59

Actually, how would the landlord know which of his residents was using all the electricity?

0ßelö7

like this fire cable mess fire hazard

John Rennie

Have you given up playing games on the PC then?

0ßelö7

@JohnRennie I don't have much time

and the games I do play (Skyrim, Fallout 4) are so poorly optimized that they don't pull 100% power

The Witcher 3 sure did

@JohnRennie I just don't turn on the fan. AC works fine.

The problem is when I go to turn on the light and miss

John Rennie

Have you looked into using the GPU for number crunching? Weren't you doing some big Monte Carlo calculations a few months back?

0ßelö7

@JohnRennie I was but those were CPU calculations and not "big"

@JohnRennie I've heard of people selling GPU time but that seems sketchy

However...it would be essentially free for me

John Rennie

18:03

@BernardoMeurer: I use a Mac Mini with an i5 as a server and it works really well.

0ßelö7

@JohnRennie Oh, I hooked up a bluetooth speaker via aux and am using it

@JohnRennie i.gyazo.com/e21d69885401e871f633b52d49f1d36c.jpg

works fine and uses no space

John Rennie

What's the make? Zen something?

0ßelö7

Zenbre

I didn't buy it, someone gave it to me

John Rennie

A Zenbre M4?

That's a perfectly good PC speaker.

0ßelö7

I don't know the model

it doesn't say

John Rennie

18:09

brobible.com/gear/article/…

Mithrandir24601

@JohnRennie I did about a year ago and so far don't regret a single penny :)

0ßelö7

yep

@Mithrandir24601 Sadly I'm bound by the Be Nice policy

just keep in mind what I said

John Rennie

@0ßelö7 if I had limited space I'd get something like that. If you feel the urge to spend your own money the Anker bluetooth speakers are allegedly very good.

0ßelö7

I need to save money

John Rennie

@Mithrandir24601 I'm too old and boring for gaming these days, but if I feel the urge to start playing Witcher 3 I'd seriously consider something like that.

0ßelö7

18:12

@JohnRennie do you have unlimited money?

get a monster rig with a custom water cooling loop

run the water through an LN2 bath

or do mineral oil cooling

John Rennie

@0ßelö7 I bought one of these to carry with me when I'm visiting family. I hook it up with the bluetooth on my laptop. And it's pretty good.

0ßelö7

@JohnRennie the sound quality on this thing is fine, I don't see myself getting anything else until it dies

I really just needed something louder than my monitor's speakers

I have good headphones for more serious affairs

John Rennie

A friend of mine bought a Dell workstation with dual 22 core Xeons, yes 44 cores, for doing finite element analysis.

lılostafa

What should I do if my advisor has asked me to do something, but can't help me with it even a little bit?

John Rennie

Well, his company bought it ...

@lılostafa ask here?

Anonymous

18:16

@lılostafa Find another advisor :P

John Rennie

@Blue PhD students will find themselves doing stuff their advisor doesn't know. It wouldn't be research otherwise.

Mithrandir24601

@0ßelö7 :P I would definitely make use of your 1080 ;) (I only have a 980, which is still fantastic)

lılostafa

@JohnRennie One (naive) question: Why is Berry connection sometimes called "Berry Potential"? Is it actually a potential that enters the Hamiltonian?

@JohnRennie So is it natural?

0ßelö7

1080 isn't that good because games are programmed awfully

especially when you start to mod them

even non-graphical mods do strange things

Mithrandir24601

Although... I do have use of the Uni's supercomputer :D

Anonymous

18:19

@JohnRennie I know. I was just joking. Well, actually I was suggesting contacting other people (professors/researchers) who know how do the task which Mostafa's advisor doesn't. Mailing such people might help. They might even lend him a helping hand (informally).

0ßelö7

which probably runs linux

Mithrandir24601

@0ßelö7 aww :/ is it any good for 4k stuff?

John Rennie

@lılostafa I don't know! You're confusing me for someone who understands quantum mechanics :-) But I'm sure the QM guys around here can help. Emilio perhaps?

0ßelö7

I don't have 4K

4K monitors are too expensive and I never want to go below 60fps

John Rennie

4

Q: How to include Berry connection in Hamiltonian?

When we calculate Berry connection, $A(R)=i<\psi(x,y)|\frac{d}{dR}|\psi(x,y)>\hat{R}$ corresponding to the Berry phase of any system, the gauge potential is related to the $R$ of the parameter space. It is not dependent on $x$ like $\psi(x)$ because in the inner product the spatial part is integr...

quantum-mechanics gauge-theory hamiltonian berry-pancharatnam-phase

0ßelö7

18:22

Atomic mass 22.98976928196 ± 0.00000000194 u

how the hell do they measure it that precisely

John Rennie

In a mass spec

Balarka Sen

@Bernardo You're fit to learn the proper meaning of a beatdown, madness, chaos in the brain

0ßelö7

@Mithrandir24601 for some reason Ultra grass kills GTA5

I get 80fps until there's grass, then 30

vzn

18:37

@BernardoMeurer let me guess, you go to beach regularly? biking too? :)

lılostafa

18:51

@JohnRennie That was almost exactly what I was looking for!

Shouldn't the Schrödinger equation have an $i$ before the $\partial_t$? If not, can you comment on the reasons? — Emilio Pisanty May 11 at 12:58

Anyone knows^ ?

Semiclassical

19:19

Easy to google: "entangled phonons"

Hard to google: "Is there an acoustic version of Bell's theorem?"

(because bells are already acoustic rimshot)

Leaky Nun

Challenge to chat: which ball reaches the ground first?

(the chain is heavy)

lılostafa

@LeakyNun together, I think. (The chain's tension is zero.)

Leaky Nun

19:34

@lılostafa did you factor in the weight of the chain?

vzn

20:03

@Semiclassical srsly? have been pondering that myself for yrs, think it is possible, have many leads

Anonymous

@lılostafa What makes you think that the chain's tension is 0 ?

Leaky Nun

right, it certainly isn't zero

Semiclassical

@vzn neat.

the word 'acoustic' is a bit misleading, of course: If all one is doing is classical wave stuff then I see no reason to expect bell-type stuff

on the other hand, if one is working with phonons i.e. quantized lattice vibrations then in principle you're in business.

@vzn This seems like a possible realization of that idea: quantumtechnology.ca/wp-content/uploads/…

@ACuriousMind you might find the above link interesting as well, given our conversation from earlier

vzn

20:27

@Semiclassical the "problem" with acoustic waves is there is supposedly no transverse wave that could give rise to an analog of "polarization orientation"... however have my doubts about that.

@Semiclassical actually there are a few relatively new papers, not widely appreciated, that insist bell nonlocality behavior can happen in classical systems and therefore the bell test, while maybe measuring presence of entanglement, is not exactly testing nonlocality.

lılostafa

@Blue because it's in free fall

@LeakyNun Yes

Anonymous

@LeakyNun I intuitively feel that the one tied to the stone should fall slower for a variety of reasons. But I won't make any bets as of now. I'll think a bit more and let you know tomorrow.

Leaky Nun

lol, both people having different answers, both being wrong

lılostafa

It's basically a ball with a massive chain attached to it, compared to a ball.

0ßelö7

Do you people not understand that heavier mass does not mean things fall faster?

Anonymous

20:36

Btw you need to mention if the height of the ceiling is greater than length of chain + stone.

Leaky Nun

and we have the third wrong answer :P

@Blue lol, sure

Bernardo Meurer

@0ßelö7 Yes it does

Leaky Nun

@0ßelö7 the heavy chain isn't in free fall

[model it as another object falling half the height]

lılostafa

@LeakyNun ?

Leaky Nun

[taking the center of mass]

vzn

20:37

@lılostafa is berry potential what your advisor is asking about?

Leaky Nun

@lılostafa it is attached to the ceiling

lılostafa

@LeakyNun the right hand part of the chain that connects it to the ceiling is irrelevant.

Anonymous

@LeakyNun It's not as easy as you might be thinking. There will be more than two possible cases to take into account. Don't forget the bending of the chain while it falls.

0ßelö7

Unless you have a video of this I won't believe anything anyone says

Newtonian mechanics of things that are not point particles is bullshit.

lılostafa

@Blue I assumed everything is ideal

Leaky Nun

20:38

Chain Drop Answer

►

Anonymous

It's a stupid question unless leaky nun mentions all the assumptions.

Leaky Nun

49 secs ago, by lılostafa

@Blue I assumed everything is ideal

:)

0ßelö7

@Blue lmao you're just mad you don't get it

Anonymous

@0ßelö7 I don't need to. You guys are assuming things to be too simple. A simple model never tells you anything about reality.

Anonymous

He didn't even take the bending factor into account

Leaky Nun

20:41

3 mins ago, by 0ßelö7

Newtonian mechanics of things that are not point particles is bullshit.

but I agree with this principle

0ßelö7

Looool blue is so salty

He would make a terrible physicist with that mindset. Good engineer though.

Anonymous

@0ßelö7 Don't worry. I'll be a good physicist. I'd like to discuss the intricacies of that experiment with @LeakyNun tomorrow. :)

Leaky Nun

I ain't no physicist

Anonymous

@LeakyNun Neither am I. Yet.

0ßelö7

Lol

Balarka Sen

20:52

Leaky's question was a trickshittery

lılostafa

@LeakyNun The problem with your sketch was that it wasn't clear where the "ground"is. and this is the key factor here. My answer would be correct if the ground was just below the "bend" in your sketch

Balarka Sen

Y'all know there's a relevant xkcd for this situation, right?

The fifth panel also applies to postmodernists.

ACuriousMind

@Semiclassical Of course you're right, since Bell's inequality is a general quantum feature you should see it with phonons like with any other setup, if you can get an experiment that produces entangled photons. I'm therefore confused what you mean by an "acoustic version" of Bell's theorem, since the theorem/inequalities themselves don't rely on any particular feature of the experiment (i.e. whether the QM states involved are photons, phonons, or something else).

@Semiclassical However, if that was just a setup for this joke, then well-done :D

@lılostafa I think it is called a "potential" because e.g. the electromagnetic potential (which is also a connection, but usually called a potential in physics) enters into the phase of states in e.g. the Aharonov-Bohm effect in the same way, i.e. the Berry connection takes the role of the electromagnetic potential/connection in this sense.

Semiclassical

More the joke.

The serious question underlying it was to novel realizations of systems with no local correlations

But "acoustic Bell" was too good to resist

lılostafa

@ACuriousMind Another thing: if it's just a phase, why does it make a measurable difference when added to a state?!

ACuriousMind

21:03

@lılostafa You can measure relative phases (i.e. if you have a state $\lvert \psi_1\rangle + \lvert \psi_2\rangle$ and $\psi_1$ shifts by the phase and $\psi_2$ not, then that does change the state)

Semiclassical

Taking two steps forward is different than taking one forward and the other backwards :)

(Or taking one step forward and then stepping one to the right, etc)

lılostafa

@ACuriousMind Yes but you could say the same about this "regular" phase:

obtained over an adiabatic process

what is special about the additional Berry phase, that may allow it to have measurable consequences?

(I'm reading this from Shankar, p.592)

ACuriousMind

@lılostafa The Berry phase is measured over a cycle of a cyclical evolution, i.e. where that phase is zero (if it never becomes zero you don't have a cyclical evolution and the Berry phase is unobservable indeed).

Anonymous

@LeakyNun In my opinion in depends on the type of material used for the chain

Anonymous

21:16

The metal chain used in that video had low resistance to bending and thus pulled the right part down

Anonymous

The effect of bending was negligible there

Anonymous

I'll surely ask this question on the main site tomorrow

Anonymous

It's a really interesting one

Leaky Nun

lol ok

Anonymous

I don't know what that lol was for but okay.

Anonymous

21:20

Thanks for sharing the question though.

Leaky Nun

thanks to veritasium

and random youtube feeds showing me this

Anonymous

Veritasium is a good channel. I liked their double slit experiment videos and spring videos.

vzn

@Blue did you see the one on oil drop/ soliton dynamics? went viral =D

Anonymous

@vzn Uh no...link please?

vzn

@Blue vzn1.wordpress.com/2016/11/07/…

Anonymous

21:30

Thanks :)

vzn

@Blue my pleasure! =D ... ps it also has double slit in it...

ACuriousMind

@vzn Could you please tone down the self-promotion a bit? I mean, the occasional link to your blog wouldn't bother me when no other resource says what you want to say, but we're at about 50 links to your blog this year alone and it's starting to feel a bit spammy to me.

4

For instance, in this case, you could have just linked the video directly.

lılostafa

@ACuriousMind OK thanks :)

vzn

22:09

@ACuriousMind uh, think you have some point but the blog highly cites/ credits stackexchange, credits people in here, etc, it was used to promote DS/ chat talks, etc. think there should be policy of encouraging blogging here by anyone. if anyone looks up youtube links in here, there are zillions. are (misc) blog links inferior somehow? do you want to crack down on too many youtube mentions? :(

lılostafa

@vzn Is there actually a "soliton" in the video?

vzn

@lılostafa (did you watch it?) its a new area of research and the terminology is in the process of being linked up, believe that the oil drop dynamics is very close to soliton dynamics, but unf nobody is "officially" making the connection yet, afaik/ afaict. the blog attempts to explain some of the connection(s) etc

ACuriousMind

@vzn People are not posting links to their own youtube videos, that's a false equivalence. I feel self-promotion (of non-SE content even more than of one's own SE content) should be done sparingly and with purpose, not whenever it just sorta-kinda relates to the topic and there's much better links one could have posted.

lılostafa

yeah I watched it from the beginning to the end

vzn

@ACuriousMind fine, but feel linking to a blog is incorrectly/ unfairly made equivalent to "self promotion" sometimes by SE mods... there is no product being sold etc... its not really "advertising"... typically link to blogs on physics etc...

ACuriousMind

22:15

@lılostafa Try watching from the end to the beginning at twice the speed, there's a ~~satanic~~ solitonic message there ;)

@vzn Currently I'm talking more as a user than as a mod, fwiw.

lılostafa

@ACuriousMind lol

I was thinking why the hell am I so tired at the same time as everyday (1:40AM). I realized that it's [actually 2:40AM](en.wikipedia.org/wiki/Daylight_saving_time !

ACuriousMind

They're not doing DST switches from Saturday to Sunday where you live?

lılostafa

who are they? I use windows (and my phone) clock

ACuriousMind

Well, whoever decides DST timings for your timezone, I have no idea

DST switch isn't here until late October, I think

vzn

@ACuriousMind personally would like to see other users blog more & channel some of all the copious chat energy into web pages. last blog link was to include physics commentary on the video. write/ chat a lot, only cf blog occasionally wrt chat dialog :|

Bernardo Meurer

22:21

I'm writing about DRM as a W3C standard for my English course

I hope the teacher understand anything I'm saying

lılostafa

Anonymous

Fortunately DST has not been implemented here :P

lılostafa

WTH I just realized I haven't had dinner yet

Bernardo Meurer

Yesterday I tried to cook frozen pasta and I triggered all the fire alarms in the house simultaneously

I'm never cooking again

0ßelö7

22:36

@BernardoMeurer why can't you be normal?

write about something like social injustice or interpersonal violence

Bernardo Meurer

@0ßelö7 She asked me to write about "a problem you're passionate about"

I literally have no passion

ACuriousMind

@BernardoMeurer Sounds like a life-extending strategy in your case :P

0ßelö7

"curvature flow"

Bernardo Meurer

I either talk about DRM or I talk about Free Software

ACuriousMind

@BernardoMeurer What about proprietary malware?

0ßelö7

22:37

@ACuriousMind did you see the picture of bernardo turning my PC into a potato?

Bernardo Meurer

@ACuriousMind Yeah, but that's less current, the DRM/EME debacle just happened

0ßelö7

Bernardo Meurer

@ACuriousMind It's too hard, cooking is dangerous

0ßelö7

@BernardoMeurer eric is pretty annoying

idk why ethan keeps having him on

Bernardo Meurer

Who?

Ah

Yeah

I agree

0ßelö7

22:41

total virtue signaler and outrage specialist

Bernardo Meurer

I also don't like Joji, he was on Hot ones today and it was really boring

0ßelö7

@BernardoMeurer Hot Ones is always r/cringe

sometimes less but always cringe

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