The h Bar

ACuriousMind

23:00

In my "defense", I've had a few beers and was just looking through my inbox when that thing popped up :P

Emilio Pisanty

@ACuriousMind beer + Stack Exchange? nerdiest combination ever.

ACuriousMind

@EmilioPisanty Well, I played Skat with friends of mine but one had to catch the last tram home, so I'm left here with a) beer and b) not being tired

Emilio Pisanty

@ACuriousMind fair enough

DanielSank

@ACuriousMind Oh, I did not know that.

~sigh~ Ok won't do it then. Also @DavidZ.

Emilio Pisanty

@ACuriousMind fancy a go at explaining phase matching instead?

@DanielSank yeah, it's a bit of a sticker shock first time one hears this

ACuriousMind

23:07

@EmilioPisanty That sounds like some important aspect of experimental physics I have no clue about, i.e. I don't even know what "phase matching" is.

Emilio Pisanty

@ACuriousMind really?

like...

at all?

DanielSank

@EmilioPisanty Dude, yeah... theorists wouldn't be exposed to that.

ACuriousMind

No, without googling it I have no idea what it even means, though I would guess it has something to do with reducing the phase difference between two lasers or something like that.

Emilio Pisanty

@ACuriousMind yeah, pretty much

DanielSank

@ACuriousMind Erm, not really.

ACuriousMind

23:09

lol

Emilio Pisanty

hahahaha

Not quite between two lasers

DanielSank

>.<

Emilio Pisanty

Say you've got a funky nonlinear crystal and you want to generate second harmonic from your laser

DanielSank

Yeah, now we're talking.

Emilio Pisanty

then there's some quadratic interaction at each bit of crystal that generates the harmonics

but your crystal is likely to be dispersive, so the second harmonic is likely to have a different phase velocity than the fundamental

so after a while, the two will be out of phase, and the harmonics generated later on in the crystal actually work against the radiation from upstream

which is bad

thence the need to not have bad things happen to your harmonics

ACuriousMind

23:12

Okay, then I understand the problem as such, but I have no idea how to actually try to migitate it.

Emilio Pisanty

@ACuriousMind yeah, I don't actually care that much either

I just need a single clean paragraph for my thesis on what the problem is and why other people need to care about it.

theorist, remember?

=P

ACuriousMind

Haha, you're talking to the wrong guy here. I'm actually considering doing my PhD in maths instead of physics.

DanielSank

@EmilioPisanty Well, you just explained it rather well.

:)

Balarka Sen

@ACuriousMind Another.

ACuriousMind

@BalarkaSen Hm?

Balarka Sen

23:15

First Danu and then you.

ACuriousMind

ah, no, Danu already switched during his master's degree

And I'm just considering it

Balarka Sen

Fair.

Emilio Pisanty

@DanielSank Yeah, but that's just the general problem

the solutions are just really long-winded

DanielSank

@EmilioPisanty What else you need to explain?

@EmilioPisanty Oh, the solutions... I see.

bolbteppa

@BalarkaSen thanks for the cool idea earlier, I find homological algebra too hard to make sure if it's true, but at least there is something to hope for :p

Emilio Pisanty

23:17

@DanielSank it's also not for second harmonic generation

DanielSank

@EmilioPisanty Do you have to focus on the optical case?

Emilio Pisanty

it's for high-harmonic generation

ACuriousMind

@BalarkaSen I actually think that the physics part interests me more, but I like the mode in which mathematicians work more.

Balarka Sen

Np. It's not a new idea, it's how topologists think about snake map.

Emilio Pisanty

think science.sciencemag.org/content/sci/336/6086/1287.full.pdf

Balarka Sen

23:17

I think Hatcher mentions it briefly.

ACuriousMind

Although I guess many people would already take offense at me calling what interests me "physics" :P

Emilio Pisanty

@DanielSank yes, very much

DanielSank

@EmilioPisanty ok

Then I won't go on and on about travelling wave parametric amplifiers.

Actually, those exist in optics too...

Emilio Pisanty

@DanielSank remind me again about those ones in about a month

they look pretty interesting

DanielSank

@EmilioPisanty k

Sir Cumference

23:20

Howdy

Emilio Pisanty

but they also look like they wouldn't take kindly to radiation from a $10^{14}\:\mathrm{W/cm^2}$ laser

bolbteppa

I would really love a 'visual complex analysis' of homological algebra tbh

Balarka Sen

People don't really visualize a lot of homological algebra, except commutative diagrams.

Every branch of mathematics has it's own way of thinking about it. You can't try to force one point of view over the other - but it's fine to be biased towards a particular POV. I am biased towards topology (aka pictures).

@ACuriousMind I see. What do you work on, in physics?

Sir Cumference

All right, anyone here good with GR?

Suddenly silence falls amongst the crowd

Um...

Balarka Sen

I know everything about GR, I have read "A Brief History of Time".

Sir Cumference

23:28

@0celo7 You like GR, right?

@BalarkaSen That's, er....not what I'm looking for

Balarka Sen

Obviously not, that was a joke :P

(I have not read "A Brief History of Time")

Sir Cumference

Yeah, I was making a joking response :P

What happened just now?

Everyone was talking, and suddenly they fall dead silent when I ask about GR...

ACuriousMind

@BalarkaSen That will hopefully be finally decided next month, currently the main options are either elliptic fibrations in string theory or topological aspects of QFT in the sense of Chern-Simons theory or general TQFTs.

Balarka Sen

@SirCumference A serial killer moving through internet, killing innocent physicists on random chatrooms.

Sir Cumference

@ACuriousMind Oh wait, you're good with GR, right?

Balarka Sen

23:31

ACM is alive because he said he might switch to math.

ACuriousMind

@SirCumference Uhhh, not really

I'm reasonably competent with the basics, but that's it

Sir Cumference

:/

Balarka Sen

@ACuriousMind Ah, I have heard those things but know nothing of anything.

I "know" what a TQFT is, but that's it. I read Lurie once.

ACuriousMind

@BalarkaSen Well, I don't know much specifics about TQFTs yet, either

But among all students, I've been told I have a much broader foundation in the necessary math than usual

Which is, admittedly, not that difficult :P

I've essentially spent the last year looking into many things, but not actually doing much

Sir Cumference

Heh

Balarka Sen

23:35

Is that an insult to the math your fellow physics students know, or an insult to the math you know (as in, it's "easy")? :P

ACuriousMind

@BalarkaSen Both :)

Balarka Sen

@SirCumference lol

ACuriousMind

I'm also not really in a hurry to get my degree since I enjoy my lazy student life far too much

Balarka Sen

Understandably.

Sir Cumference

Ya know, it gets so boring on SE that sometimes I look forward to bad questions

Anyone know what I mean?

Just ones that are so bad, they're kind of funny

Which I, of course, flag

ACuriousMind

23:39

@EmilioPisanty Hm, someone edited the all caps back in...

Sir Cumference

Like this one

ACuriousMind

@SirCumference I could easily do without all the silly questions

A day without a question to get exasperated about would be nice

Sir Cumference

Really? It gets a bit boring, doesn't it?

A laugh once in a while isn't too bad

ACuriousMind

for all the good questions and answers, SE is an amazing place

Sir Cumference

True, it's not intended to be a joke

peterh

23:43

@ACuriousMind New avatar... of course a lawful evil one, as always :-)

Balarka Sen

@SirCumference I actually don't know the answer to that question.

Sir Cumference

But once in a while, it can be worth a laugh

ACuriousMind

And the bad ones need moderation.

Sir Cumference

Like this question

On astronomy

ACuriousMind

@peterh Whether Kreia/Darth Traya is "lawful evil", or indeed fits anywhere into the DnD alignment scheme, is an interesting debate

Balarka Sen

23:44

Sounds like worldbuilding.SE

Sir Cumference

Or this

ACuriousMind

Pressing entities into the DnD scheme is always rather difficult, because the DnD universe is one with objective morality - it doesn't matter what you personal views are, each action, in principle, has an objective moral value assigned to it

peterh

@ACuriousMind Ok. Darth Vader is viewed as an example of a LE personality, although in the other sith gurus I am not sure.

ACuriousMind

The morality of the Star Wars universe is different, but also objective: The force does decide who is "Jedi" and who is "Sith"

The interesting thing about Kreia's character is that she rejects the standard Star Wars morality - she thinks both the Sith and the Jedi are misguided

peterh

@ACuriousMind The force decides, and not the persons own will? What can be manipulated, but finally the person decides?

@ACuriousMind Wow! I read after it.

Sir Cumference

23:48

Oh, found it

ACuriousMind

Kreia's morality always seemed kind of Nietzschean to me - those who reject the "slave morality" of the Jedi and the Sith are those who truly wield power

It doesn't really become clear in the course of the game what her actual moral conviction is - the "boss fight" at the end of the game painting her as ultimately Sith is conceivably due to the developers running out of time

peterh

@ACuriousMind It seems to me then more like chaotic neutral! Wow! It is then a significant switch.

ACuriousMind

@peterh Oh, you've hit a topic I can debate about endlessly: DnD chaotic neutral is a conception of morality that is just "do as thou wilt"

That's not what Kreia is - she does have aspirations to make the universe a better place

And she also has decided that neither the pure Jedi nor the Sith path is the correct way ot achieve that vision

peterh

@ACuriousMind Then CG!!! You take a helm of opposite alignment? :-)

ACuriousMind

@peterh Haha. But "Chaotic Good" is a morality that always helps the weak and the oppressed. That not what Kreia advocates, either

She doesn't approve of helping those who can't help themselves, but she doesn't approve of using them to your own gain, either

Neither the DnD nor the Star Wars moralities have an appropriate archetype for her, and that's what makes her character so compelling

peterh

23:57

@ACuriousMind I think I have to read Nietzsche.

ACuriousMind

I don't identify with her idea of morality (that's not how I choose my profile pictures at all), but I think she presents ample opportunity to reflect on what is "good" or "evil", as opposed to blindly following the Jedi or Sith paths

Emilio Pisanty

@ACuriousMind yeah, I saw it

physics.stackexchange.com/review/suggested-edits/142909

no idea why it was approved

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