The h Bar

getafix

02:05

a quick question, I am trying to prove that tensor operators $$[V^{(1)}\otimes W^{(1)}]^{(1)}_{M}$$ are proportional to the three components of the vector cross product of V,W

Things are defined as follows

$$[V^{(1)}\otimes W^{(1)}]^{(K)}_{M} = \sum_{p,q} \langle 1,1; p,q| K,M\rangle V^{(1)}_{p} W^{(1)}_{p}$$

and $$V^{(1)}_{\pm 1} = \mp\frac{1}{\sqrt{2}}(V_x \pm iV_y)$$
$$V^{(1)}_{0} = V_z$$

I was able to show, $$[V^{(1)}\otimes W^{(1)}]^{(1)}_{0} = (i/\sqrt{2})(V \times W).\hat{z}$$

but, for $$[V^{(1)}\otimes W^{(1)}]^{(1)}_{-1} = (1/ \sqrt{2})V^{(1)}_{0} W^{(1)}_{-1} - (1/ \sqrt{2})V^{(1)}_{-1} W^{(1)}_{0} $$ i get terms that don't cancel out

I am using the fact that the clebsch-gordan coefficients in the sum are zero whenever p+q =/= M

as far as i know for each value of M which runs from -1,0,1 the tensor operator should be proportional to a component of the vector cross product for the the case of K = 1, M = -1, I get that it is a linear combination of 2 components of the vector cross product, I am pretty sure this incorrect, unless someone here knows otherwise perhaps?

Sir Cumference

04:50

0

Q: Wedding and death related

My elder brother expired on 02-12-2017. All the rituals were properly performed. wedding of my niece is going to take place on 02-12-2018 exactly on the anniversary date of my elder brother's death..Both are related to my own father.Are the happenings of astronomical significance.Is/are these e...

Probably 5 out of 10 people confuse astronomy with astrology.

Anonymous

05:46

@SirCumference It might be on-topic on Hinduism SE

Anonymous

@SirCumference Yeah, that sucks :/

Abcd

06:07

oho

Physics Meta

07:08

-2

Q: Should this really be put on hold?

Why are questions concerning the consistency of different parts of mainstream physics with one another considered as questions about non-mainstream physics and put on hold? I asked a question about how different parts of mainstream physics that to me seemed inconsistent with one another were con...

discussion scope specific-question reopen non-mainstream-physics

deadpool

07:35

@JohnRennie in your question physics.stackexchange.com/questions/82678/… i believe you considered time dilation due to gravity. My question is the same but instead i am thinking about time dilation due to speeds close to c. Or maybe i understood wrong :)

John Rennie

@deadpool yes, I agree, your question is different.

But my concern is still that I'm not sure what you mean by the end of the universe, because I doubt the universe has an end.

Abcd

@JohnRennie Why is my Fn + Brightness (F3) not working?

@JohnRennie Fn + F8 (Sound level) on the other hand, works properly.

John Rennie

No idea, sorry

Is the F3 key working?

Abcd

Yes

John Rennie

And the Fn key is obviously working since it works with Fn+F8 ...

Remind me what model your laptop is. It's a Samsung isn't it?

Abcd

07:53

@JohnRennie yes

John Rennie

Some Googling suggests the power settings can interfere with the manual screen brightness control ...

Abcd

@JohnRennie what are power settings

John Rennie

08:15

@Abcd Open control Panel and click the Power Options link.

Then click Change Plan Settings, then Change Advanced Power Settings, and in the new windows scroll down and find the Display heading.

Abcd

@JohnRennie found,then?

John Rennie

@Abcd I found some posts on the Internet saying these settings can interfere with the manual brightness control, but it didn't give any details. Is Enable adaptive brightness on? That would be an obvious suspect.

Abcd

Turned it off right now

but still not working

John Rennie

What are the other settings? Can you expand them all and post a screengrab?

Abcd

John Rennie

08:27

Ah, I meant the other display settings. I'm working on a PC not a laptop so my display settings are different. I wanted to see what the display settings were set to.

Abcd

John Rennie

Hmm, they all look fine.

If you have now disabled adaptive brightness try restarting and see if that makes a difference.

Slereah

08:44

hey dudes

deadpool

@JohnRennie like a Big Freeze ? Or just like you phrased it -can he "see the universe age by an infinite time? "

Slereah

it is what did this morning

Age by an infinite time

John Rennie

@deadpool the thing about falling into a black hole is that the time dilation becomes infinite at the event horizon, while in your example the time dilation is just a finite and constant factor. So the two situations are rather different.

For the guy falling into a black hole it takes only a finite time for an infinite time to pass outside the black hole.

In your case it still takes an infinite time for an infinite time to pass for the rest of the universe.

deadpool

09:13

@JohnRennie at first i wanted to know what would happen if i travelled exactly at the speed of light. In that case the time dilation would become infinite correct?

@JohnRennie i know that is not possible but that thought experiment always made me wonder :)

John Rennie

@deadpool it's impossible to travel at the speed of light.

deadpool

i know that is not possible but that thought experiment always made me wonder.

Can we look at it from a photon's point of view?

@JohnRennie

John Rennie

A photon has no point of view. It has no rest frame.

Emilio Pisanty

11:26

Hey @DavidZ, how was my comment here obsolete? "This answer is misleading" doesn't become obsolete unless the answer gets fixed (which it hasn't).

deadpool

13:29

@JohnRennie @JohnRennie can we assume he can attain speed of light in this case? I am more interested in knowing your answer on what happens afterwards.

rob

@deadpool It was supposedly a long-standing question about imagining the rest frame of a ray of light that led Einstein to develop relativity, in which such a perspective is impossible.

Think about how the electric and magnetic fields would look in the rest frame of a light ray: complicated and varying in space, but without any charges or currents to produce them.

The best response to your question really is that it doesn't make sense to imagine traveling at the speed of light. It is a non-trivial result.

deadpool

14:15

@rob i understand :)

Jake Rose

$\mui$

Does the equation $B = \mu_0 \mu_r H$ always hold? Even when B isnt proportional to H?

Ie is the non linear behaviour 'absorbed' by the $\mu_r$?

Semiclassical

14:41

It can’t generically hold like that—what if the H and B fields point in different directions at a given point?

Jake Rose

I was thinking about that too

$\mu_r$ becomes negative?

But im pretty sure its defined to be real positive

Semiclassical

That won’t be enough. If $\vec{B}=\mu \vec{H}$, then the two fields are parallel at every point in space

Jake Rose

Can they not be?

Is there a generilsation which takes all of this into account?

Semiclassical

(What I said is true even if you allow $\mu$ to be itself a function of position)

There is, actually

You can generalize it by requiring that the components of B be linear functions of the components of H

Or, in other words: we should obtain $\vec{B}$ as a linear transformation of $\vec{H}$

Do you know how to effect such a linear transformation on a vector?

Jake Rose

Not quite

@Semiclassical Can I aska tangential question

Im doing a formal report write up atm you see and Im a little confused

We'rre measuring B and H for different materials using a large solenoid to create an external H field which can be calculated, and then a smaller solenoid with a sample of the material inside to measure B

And then plotting these against eachother to produce a hysteresis loop

But why is the external H the same as the one inside of it?

Semiclassical

14:57

Isn’t that how H-fields work? They’re generated by free currents, not bound currents

Jake Rose

Oh yeah I see

So H wouldnt change in the material

Semiclassical

Right.

It does make me wonder if there are materials which would produce a free current upon imposing an external H-field tho

For instance, an electron moving through a magnetic field gradient will be deflected due to its spin ie its intrinsic magnetic moment

So I could see that being relevant in a field like spintronics: en.m.wikipedia.org/wiki/Spintronics

I think I may be over-complicating it tho

Jake Rose

15:21

though it is cool

Anybody know of a way f using latex in word without having to press equation every time?

Yashas

For an operator $\hat{A}$, show that $\left(\hat{A}^\dagger\right)^\dagger = \hat{A}$

how do I prove such a thing?

The dagger represents Hermitian transpose

Slereah

$\hat{A}^\dagger$ means that $\langle \alpha, \hat{A}^\dagger \beta \rangle = \langle \hat{A} \alpha, \beta \rangle$

So $$\langle \alpha, (\hat{A}^\dagger)^\dagger \beta \rangle = \langle \hat{A}^\dagger \alpha, \beta \rangle$$

$$\langle \hat{A}^\dagger \alpha, \beta \rangle = (\langle \beta, \hat{A}^\dagger \alpha \rangle)^*$$

$$(\langle \beta, \hat{A}^\dagger \alpha \rangle)^* = (\langle \hat{A} \beta, \alpha \rangle)^*$$

$$(\langle \hat{A} \beta, \alpha \rangle)^* = \langle \alpha, \hat{A} \beta \rangle$$

Badabing badaboum

Jake Rose

Could you also do it via $(A^\dagger) = (A^*)^T$
thus $(A^\dagger)^\dagger = (((A^*)^T)^T)^* = A$

(I havent used the notation you used before, think I do it next term)

Slereah

I wouldn't.

Jake Rose

How come? Is it just stupid?

Slereah

15:30

That's only really valid for finite dimensional Hilbert spaces

Yashas

@JakeRose The question appears to be sufficiently silly that I'm not sure if I am even allowed to assume that transpose and conjugate are reversible.

and yeah I think I can't do that as there are infinite dimensions

Jake Rose

@Yashas @Slereah Ahh I see

My linear algebra is still somewhat primitive

Yashas

My linear algebra is non-existent

Slereah

you rarely learn hilbert space stuff correctly in physics

Jake Rose

Just for reference

@Slereah not useful?

Slereah

15:31

Well you know

It's physicist math

Jake Rose

True I suppose

Yashas

It also seems that physicists mean to say $L^2$ space when they say Hilbert space (I don't understand neither though :P).

Jake Rose

I think the maths for physicists course here is pretty competent

Not on par with mathmos

But probably more on par with mathematics elsewhere

Slereah

In QM you almost exclusively use $L^2$, $\ell^2$ or a finite dimensional Hilbert space, so just $\mathbb{C}^n$

You don't really use any fancier Hilbert space

Jake Rose

$B = \mu_0 \mu_r h$

oops sorry

Emilio Pisanty

15:51

@JakeRose transpose and conjugate are basis-dependent. @Slereah's proof hinges on a basis-independent definition of the hermitian conjugate, which is almost always just plain better.

Yashas

$\det(e^\hat{A}) = e^{\text{tr}(\hat{A})}$

how do I start?

I have more math questions in my QM assignment than actual QM stuff .-.

Slereah

@Yashas Express the exponential as a Taylor series

Emilio Pisanty

@Yashas in finite dimensions?

Yashas

@EmilioPisanty infinite

Emilio Pisanty

if not, then you're in for a world of pain, and the result will require some fairly strong additional assumptions on $\hat A$ beyond "it's an operator"

Slereah

16:00

Don't you need like compactness or something

or self-adjoint

I forget

Yashas

the question also said $\hat{A}$ is diagonalizable which I think is implied by it being an operator

Emilio Pisanty

well

at the very least you need it to be trace-class

or the whole thing makes no sense

you also need a credible definition of determinant

@Yashas $\hat A$ is an operator $\Huge \implies\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!/ \ \ \ \ $ $\hat A$ is diagonalizable

what is this for? an intro-QM class?

Yashas

@EmilioPisanty Yes

Emilio Pisanty

@Yashas it doesn't really work as an argument, but I guess it's reasonably clear what they expect you to say

Yashas

I thought all measurements of an operator are its eigenvalues. Hence, the operator must be diagonalizable?

Emilio Pisanty

16:05

assume for the moment that this is in finite dimension

Yashas

Actually I'm not really sure how much of finite dimension LA arguments are applicable in in infinite dimensions.

Emilio Pisanty

@Yashas they're not

but you won't be able to make headway on that question without assuming that

if you're in infinite dimensions, then basic linear-algebra statements about matrices like "the trace exists" are no longer guaranteed

Unless your problem text explicitly says that $\hat A$ is trace-class, then it's already playing fast and loose with rigour

and, by extension, it's expecting you to do the same.

Anyways, the linear-algebra perspective is to shift to a basis where $A$ is diagonal

and where the exponential $e^A$ is therefore just the exponentiated diagonal elements

and where the determinant is just the product of all the diagonal elements

... which are basically enough ingredients to reconstruct the identity you're after

Now, as you note, that argument doesn't hold in infinite dimensions, because both the determinant and the trace would require limiting procedures with (i) no guarantee that they converge and (ii) no guarantee that the result will be basis-independent.

However, unless you've been given strict rigorous definitions of the determinant, trace, and operator exponential, then it's pretty pointless to ask about rigour.

Slereah

Just write $\det A = \prod_i A_i$

It should work fine

Emilio Pisanty

@Slereah you're missing a step

"ignore all convergence issues"

then it works fine

Slereah

That's what you do when you do physics @EmilioPisanty

Emilio Pisanty

16:13

@Slereah indeed

Slereah

Hell I'm assuming that eigenvalues exist at all

That's already insane!

Emilio Pisanty

this is why I asked

9 mins ago, by Emilio Pisanty

what is this for? an intro-QM class?

if it was for a mathematician's-perspective thing, then it'd be a whole 'nother ball game

Yashas

$A = P^{-1}DP$

$\det({e^A}) = \det(e^D) = e^{\lambda_1 + \ldots + \lambda_n}$

how much of scam is this?

nvm

I am probably going to ask for a clarification for this quesiton from my TA.

Consider a one-dimensional bound particle. Show that, if a particle is in a stationary state at a given time, then it will always remain in a stationary state.

is that even true?

If I find the particle to be in a stationary state at a point $t$, then if I leave the system on its own, it would again get jumbled and my next measurement could give some other E?

Anonymous

16:31

@Yashas It's fine and rigorous. Sylvester's formula. But oh, wait. Is $D$ diagonal?

Space Otter

In Millikan's oil drop experiment, why did he choose to measure the velocity upwards in a strong field rather than just capturing an oil droplet and measuring the field strength required to keep it stationary, in his paper he even talks about how stokes law breaks down for spheres with small radiuses.

Does the method of measuring field strength for stationary droplet and terminal velocity without any E field not result in a smaller error?

By eliminating the slip factor needed in Stokes law for the upward motion at least.

Yashas

@Blue Yes.

Anonymous

@Yashas If $D$ is diagonal, then it's perfectly fine.

Anonymous

$A=P^{-1}DP\implies e^A=P^{-1}e^DP$

Yashas

I don't think that formula is allowed for infinite dimensions.

Anonymous

16:35

Are you studying functional analysis?

Yashas

QM

Physics Meta

0

Q: What is the line between fiction and physics with respect to off-topic

There is a question I believe to be well on topic, relevant, and interesting. It is asking to consider a fictional scenario and evaluate, as given in the fictional scenario, whether it is possible to achieve with classical physics. It is, I believe, people who are misapplying the prohibition ag...

discussion scope vote-to-close

Anonymous

@Yashas For infinite dimensional operators, there are a lot of other things to be taken into consideration. You'd have to precisely define the type of operators you're dealing with. I don't think just calling $D$ a diagonal operator makes sense

Anonymous

Are you sure you're being taught infinite dimensional QM with operations like these? Then you'd probably have to direct those questions to ACuriousMind

Emilio Pisanty

@Yashas it's a QM class. "allowed" is not a very useful word there.

the formula is certainly not allowed for general operators in infinite dimensions

but it is also valid for nice-enough operators in infinite dimensions

if it's a functional-analysis class, the viewport is to start with a rigorous foundation, define your budget in terms of how nice of an operator class you're dealing with, and then work up to see how much you managed to buy, i.e. how strong of a result you managed to prove.

if it's a QM class, you need to ditch that debit-based system and take a credit-based approach

a.k.a. asking for forgiveness instead of asking for permission

3

Anonymous

16:45

@EmilioPisanty lol :P

Emilio Pisanty

assume that your operator is nice enough, and prove the result that you need. Then you go to the ~~cashier~~ mathematician and you ask ~~how much you owe~~ what "nice enough" needs to mean in order for your result to be true

danielunderwood

Or you forget about it until you later realize that interest can hurt

Sir Cumference

Howdy

How's life

enumaris

whomp

Slereah

@danielunderwood that's what happens when you try do solve particle on a ring

Sir Cumference

16:58

Don't suppose anyone knows how to concatenate Word files with heavy amounts of equations? Wrote several proofs and am trying to put the correct ones together to hand in, but Word crashes when I copy certain equations

Emilio Pisanty

@SirCumference color me surprised

John Rennie

@SirCumference Use links rather than trying to import everything into a single document.

Sir Cumference

@EmilioPisanty Yep I know...this is like the 15th time I've come here about word

Emilio Pisanty

@Slereah ooooooohhhh, indeed it does

Sir Cumference

Perhaps I ought to look at other software

Emilio Pisanty

16:59

@SirCumference I don't think I can recall you talking about word

but Word crashing

Sir Cumference

@JohnRennie Links?

enumaris

dunno how to do work post-thanksgiving weekend

feels sluggish

Emilio Pisanty

John Rennie

@SirCumference Google Google

Semiclassical

@EmilioPisanty I'm always a bit amazed at exactly how awful that gets

Sir Cumference

17:02

@JohnRennie Hmm, well these are being handed in on paper

Emilio Pisanty

@Semiclassical yeah, I know

enumaris

@danielunderwood I planned on working on the RL library over the long weekend, but I did not lol

Sir Cumference

Oh wait, it displays the actual text

Emilio Pisanty

I showed you the slides for that lecture, right?

enumaris

watched 2 movies, played CSGO and Overwatch...ate a lot...

Semiclassical

17:02

ya

John Rennie

@SirCumference IIRC when you go to print it Word correctly pulls in all the links and prints it as if it were a single huge document.

Emilio Pisanty

it was pretty fun watching the mounting disbelief XP

enumaris

bought a new laptop for black friday...

Semiclassical

haaaah

Anonymous

@EmilioPisanty Just curious - did you ever have to take a functional analysis class with a focus on QM? Or a pure functional analysis class (like, from a math student's perspective)?

Emilio Pisanty

17:03

@Blue nope

never had to

never did

John Rennie

@enumaris New laptop!!! :-)))

Emilio Pisanty

never did take any formal functional analysis

enumaris

yeah, it's being shipped to me

will arrive on Wednesday supposedly :D

Emilio Pisanty

would've liked to in undergrad, but I only made it through Analysis I and II, and functional analysis was on III

Anonymous

Ah. But you do seem to know a fair bit of it (that's the impression I get from your PSE answers), as far as QM is concerned. Just picked them over time? :)

John Rennie

17:04

@enumaris details?

Emilio Pisanty

would've liked to audit mathematician's FA on my first year of PhD but that just turned out to be unrealistic

enumaris

@JohnRennie It's a gaming laptop for me to waste more time on lol. Razer 15 incher

Emilio Pisanty

and also I felt like a grampa next to all them undergrads

@Blue yep

Anonymous

@EmilioPisanty Hehe :P

Sir Cumference

@JohnRennie Neat, thanks!

Emilio Pisanty

17:05

but my formal FA is pretty limited

enumaris

pretty good specs, but nothing super amazing. Not as powerful as my 1 year old desktop, but should be good enough to play the games I want on :D

Semiclassical

one bit of mathematica notation which I can never seem to remember: picking out specific elements from an array

danielunderwood

@enumaris yeah I played a bit of Overwatch too. I started the RNN course which has been pretty interesting so far. Though I've gotten sidetracked trying to write a music generator a bit better than the homework assignment

enumaris

also, Razer makes an external GPU holder thingy...so if the GPU ever gets outdated, I can upgrade to an external one

Semiclassical

Take almost works, but not quite

John Rennie

17:05

@SirCumference I am the Ubernerd!

4

Emilio Pisanty

@Semiclassical list[[i]]?

enumaris

@danielunderwood I only have like 5 hours on overwatch so far, I just sort of picked it up...trying to get better at the snipers

Semiclassical

that's fine for one element

enumaris

widow and ana

John Rennie

@enumaris through a Thunderbolt port?

enumaris

17:06

@JohnRennie yep

Emilio Pisanty

@Semiclassical what do you need, exactly?

Semiclassical

i guess i can just do {list[[i]],list[[j]],list[[k]]}

Trying to pick out the unique matrix elements from a triangular matrix

Emilio Pisanty

@Semiclassical if that's what you're doing, I would write list[[ {i,j,k} ]] instead

Semiclassical

hmm

enumaris

@JohnRennie I used to have a Sony that had an external GPU and that worked out pretty well so I'm thinking this one should be fine if I ever need it :P

Anonymous

17:07

@EmilioPisanty Oh, btw Analysis I and II were like Rudin type - baby Rudin and papa Rudin?

Emilio Pisanty

or, if they're consecutive, list[[ i;;k ]]

Sir Cumference

@EmilioPisanty For real tho, I'm noticing Word can't handle equation heavy documents. Maybe it's time to go to LaTeX

Semiclassical

ah, right, it's Part

Emilio Pisanty

@Blue not quite. Analysis I was papa rudin, I think, and II was measure theory

@SirCumference yes, yes it is.

enumaris

@JohnRennie this one is gonna run Windows 10 so if I ever brick it (e.g. by trying to do deep learning on it or something) I'll come to you for tech support XD (just don't tell Bernardo)

Anonymous

17:08

@EmilioPisanty Gotcha. Thanks :)

John Rennie

@enumaris has it got an SSD?

enumaris

yeah 512gb SSD

Sir Cumference

Only thing I'm hesitant about is the lack of quick keyboard commands for equation editing, e.g. on Word, alt+V will do a square root (on Mac) rather than needing to type \sqrt{}

John Rennie

(Bernardo will install some weird variant of Linux on it :-)

Emilio Pisanty

which then makes a nice solid base for FA on III and god-knows-what on IV

never saw what's in there, though

enumaris

17:09

lack of end parenthesis...*triggered*

John Rennie

But :-)) just looks like I have a double chin!

Emilio Pisanty

@Semiclassical yeah, if you know which elements you want (by index), then it's always Part

Semiclassical

yeah. my brain just never remembers the word

Emilio Pisanty

otherwise you're looking at some combination of Position and/or Select and/or other dubious ingredients

@Semiclassical I've never seen Part laid out explicitly in code and thought "yeah, that syntax is clearer than [[ ... ]]"

Semiclassical

yeah

Slereah

17:11

@EmilioPisanty Hey btw

what do I do if I want to try to apply to the PhD you're offering

do I send a mail to the other guy

Semiclassical

of course, since I"m dealing with a symmetric matrix, I probably could've just tossed in a DeleteDuplicates call after Flatten-ing it

enumaris

whoop, I got the names mixed up and thought semiclassical was asking about applying to a PhD...was like...yo bro you just finished one...

Emilio Pisanty

@Slereah I'm not sure I could fairly describe it as us offering a PhD project. We don't currently have funding specifically assigned to it. But we're certainly interested in students.

There's central ICFO funding which would require you to make an application to the main pool

phd.icfo.eu/phd-icfo

Slereah

@EmilioPisanty Well you know

Who has funding really

The only one with financing are the boring ones

On like nanophysics or solid states

From BIG MONEY

Emilio Pisanty

and there it's always a plus if you have a specific project in mind already talked-about with a potential supervisor

Slereah

17:15

I don't have a specific project in mind

I mean I have ideas of things to do in physics, y'know

Sir Cumference

9 pages of proofs. Imagine a world where math courses satisfied Writing Intensive requirements

enumaris

@Slereah fully develop Einstein-Cartan theory?

Emilio Pisanty

@Slereah so basically yes, write to Lewenstein

Slereah

But they're just stupid ideas that will not be very interesting to financing people I would guess

enumaris

Alright physics nerds: is Oumuamua an Alien spacecraft or not?

Slereah

17:16

@enumaris I think Einstein and Cartan did it first

enumaris

@Slereah quantize it :P

Slereah

@enumaris I think that has been done too!

Sir Cumference

@enumaris Yes

enumaris

@Slereah so is it a quantum theory of gravity?

Slereah

Sure, there's tons of quantum theories of gravity

Including a bunch where the connection isn't symmetric

Emilio Pisanty

17:18

@Slereah It depends how much you care about doing something specific. I'm looking for students for the quantum-optical HHG project I linked earlier, and for extensions to the work in arxiv.org/abs/1808.05193

there's obviously other people doing interesting things in the Lewenstein group

Sir Cumference

Oh @EmilioPisanty, I think you mentioned reading Spivak's Calc on Manifolds once right?

Emilio Pisanty

the more specific you can get when writing, the more likely it is that Lewenstein will be interested

Slereah

Well you know

I'm not well versed in quantum optics

So obviously I don't really have a project in mind

Emilio Pisanty

@Slereah if it's for a master's project it's better if you have more background, because there isn't a lot of time to get up to speed

on a PhD it matters more that you're able to learn quickly

Slereah

u know me I'm great

Emilio Pisanty

17:22

@Slereah that definitely counts.

Slereah

any good recommendation on a quantum optics book btw?

Walls and Millburn is the one I usually plan on buying

Emilio Pisanty

Gerry & Knight

also Scully & Zubairy

that project is a bit demanding in that it melds together two parts of optics (quantum optics & strong-field physics) which haven't spoken to each other very much over the past 25 years

which means that you need to get up to speed on two independent subfields

but

enumaris

@SirCumference well then...

Emilio Pisanty

it also means that you're one of the first working on non-perturbative non-linear quantum optics

Sir Cumference

@enumaris ?

Semiclassical

17:25

that's pretty cool

Emilio Pisanty

I mean, as of now there are three papers on the subject, basically.

Semiclassical

non-perturbative stuff in general is something I'd like to see more of, though of course that's an overly broad classification

Slereah

@EmilioPisanty Do I have to solve QED

Emilio Pisanty

@Semiclassical well, any field that defines itself as non-X is always going to be pretty broad

@Slereah no.

Semiclassical

true

Slereah

17:27

Phew

Might have been tricky

Is it gonna be

The solitons

Semiclassical

if it's nonlinear, it's probably related to solitons somehow

Emilio Pisanty

@Slereah not particularly, no.

@Semiclassical solitons are quadratic nonlinearities

Semiclassical

hmm

Emilio Pisanty

we're looking at (what would count as) nonlinear orders in the tens or hundreds

Semiclassical

jeeze

Emilio Pisanty

17:28

though again, the concept of nonlinear order is pretty meaningless since perturbation theory breaks

Semiclassical

right

Emilio Pisanty

@Semiclassical well, how else do you get a 200th harmonic?

when we say high we mean high

Semiclassical

it reminds me of something out of the book Watership Down, where the counting system for rabbits goes as: one, two, three, four, hrair (i.e. "many")

Slereah

is that even measurable?

@Semiclassical u embleer frith

Semiclassical

lol

good book. haven't read it in a while

Slereah

17:31

Movie's pretty good too

Emilio Pisanty

"Watership Down" in "Donnie Darko" www.filmserts.com

►

Slereah

also Netflix is making a reboot

Emilio Pisanty

this is the most I've seen of watership down

Semiclassical

@Slereah hmmmmmmm

Slereah

@EmilioPisanty dailymotion.com/video/xyucbo

Have the intro then

subtitled in spanish, coincidentally

The intro is very cute

and then it's 1 hour of rabbit holocaust

Watership Down - Holly's Memory of the Warren's Destruction

►

The horror

enumaris

17:35

@SirCumference how long until the creators of Oumuamua make contact with us?

Sir Cumference

@enumaris I'm no visionary so I can't be certain. But perhaps some astrology will help us find out

danielunderwood

who says they haven't already?

enumaris

hmmm

Slereah

Legs

►

enumaris

so hard to find a timeline where Tensorflow and pytorch will support cuda 10...

looks like Tensorflow 2.0 will support it

not sure when that will drop...there has apparently been no talk in the pytorch community about an official version that supports it

yuck

danielunderwood

17:55

you could always implement it yourself...sounds fun doesn't it?!

Does intern mean something different than it used to? I'm seeing internships that are looking for people with previous industry work or an advanced degree

enumaris

well I can build them from source

probably just have to modify a couple lines of code to include "cuda10.0" flag instead of "cuda9.0" flag...but

that's a giant pain and I'm not really gonna get into it

ACuriousMind

@danielunderwood It means "slave".

Nothing wrong with looking for slaves with experience :P

enumaris

@danielunderwood gotta love them unpaid internships that require 5 years experience and SME level knowledge.

danielunderwood

@enumaris think back to that when your compiler explodes from errors

Semiclassical

At least grad school has stipends lol

Wanting to be anAndroidDevelor

17:58

can I ask a question here?

enumaris

@danielunderwood I'd rather not, thx

Semiclassical

(So more like “indentured servant” maybe)

enumaris

@WantingtobeanAndroidDevelor see top right

Wanting to be anAndroidDevelor

I see

enumaris

my grad school experience was pretty chill tbh

I never had to write grant proposals

danielunderwood

17:59

Well most of them that I've seen seem to be paid at least. But I have seen some that did indeed look like they wanted slaves

enumaris

I met my adviser like once a week for my entire time there

Wanting to be anAndroidDevelor

so Im thinking of writing a program that simulate chemical bond from quantum mechanics view

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