The h Bar

0celouvskyopoulo7

13:10

@BalarkaSen If $S=\cup_{d\in\Bbb R}S^d$ is a "filtered * algebra" does that just mean that there's a multiplication $S^d\times S^e\to S^{d+e}$ and an involution $*:S^d\to S^d$?

Slereah

you know I really have no clue how one proves the second law of thermodynamics

I don't even know what process you'd use

Something information theory related, I guess?

0celouvskyopoulo7

it's a postulate, not a theorem

Slereah

Is it?

I know it can be violated for some systems

So obviously it's not a postulate

0celouvskyopoulo7

what?

every postulate is violated in some situation

if it weren't, we'd have a toe

Slereah

Well yes, but then that means that there's a reason why it makes sense in a context

I'm guessing it would have to be something related to QM projectors or something

Since macrostates are impure states

0celouvskyopoulo7

13:13

@BalarkaSen I'm unclear on the difference between a filtered algebra and a graded algebra

Slereah

and since the violation is related to negative energies I'm guessing it involves time evolution something something

Something like Hamiltonian with a lower bound applied to the entropy

0celouvskyopoulo7

25

Q: Is there any proof for the 2nd law of thermodynamics?

Are there any analytical proofs for the 2nd law of thermodynamics? Or is it based entirely on empirical evidence?

Lumo has an answer

Slereah

"The more rigorous versions of this proof are always variations of the 1872 proof of the so-called H-theorem by Ludwig Boltzmann"

Good old Boltzmann

0celouvskyopoulo7

entropy is very important in Ricci flow

things like $\int R\log R\, dv$

Slereah

"The H-theorem depends upon the stosszahlansatz assumption"

wot

0celouvskyopoulo7

13:25

The problem with the Hamilton entropy is that it's actually monotone decreasing

I guess Hamilton failed thermo in school

@Slereah collision count ansatz?

Bernardo Meurer

@0celouvskyopoulo7 Help

I have only ate pizza for the last 5 days

I haven't shaved and I lost my razor

Slereah

@BernardoMeurer I hope you're fond of diarrhea

Just win baby

even Einstein failed his entrance exam

0celouvskyopoulo7

On a similar note, I think I had under cooked chicken the other day

Bernardo Meurer

@Slereah My feces have been actually very consistent

Slereah

13:28

as is well known

2

0celouvskyopoulo7

Probably inappropriate.

@BernardoMeurer Just don't eat anything

Slereah

There's nothing inappropriate about history

0celouvskyopoulo7

yesterday I skipped two meals because I was still full from my creation the night before

Just win baby

chicken?

0celouvskyopoulo7

A casserole

Just win baby

13:30

any meat?

0celouvskyopoulo7

pulled pork

Slereah

@0celouvskyopoulo7 that is inappropriate

0celouvskyopoulo7

?

Just win baby

??

Slereah

(INNUENDO)

I should check the Boltzmann proof, really

I have no idea how he proved it before quantization of the phase space

Just win baby

13:31

Pulled pork

Pulled pork is a method of cooking pork where what would otherwise be a tough cut of meat is cooked slowly at low temperatures, allowing the meat to become tender enough so that it can be "pulled", or easily broken into individual pieces. Pulled pork is found around the world in a variety of forms. == Preparation == Pulled pork, usually shoulder cut (sometimes referred to as mixed cuts), is commonly slow-cooked by a smoking method, though a non-barbecue method might also be employed using a slow cooker or a domestic oven. In rural areas across the United States, either a pig roast/whole hog, mixed...

0celouvskyopoulo7

pulled pork is probably the greatest invention

Just win baby

58 mins ago, by Just win baby

Let's talk about cooking :-)

Balarka Sen

@0celo I am not familiar with filtered algebras.

Slereah

what about fire

Balarka Sen

Graded are when you have a multiplication map.

0celouvskyopoulo7

13:33

@BalarkaSen According to wiki, it's just an extension of a grading to a field

$A=\cup_{l\in \Bbb F}A^l$

Balarka Sen

isee.jpeg

Slereah

that's a lot of gradings

Balarka Sen

not if F is a finite field

mod p gradings yo

Slereah

5646c965-a-62cb3a1a-s-sites.googlegroups.com/site/…

I'm guessing I'm not gonna read the original paper

0celouvskyopoulo7

@BalarkaSen I am derping though. If $S^d_p$ is the the space of variable-coefficient polynomials in $n$ variables of degree $d$, why is $S^d_p/S^{d-1}_p$ isomorphic to the space of homogeneous polynomials? Something something mod the inhomogeneous terms?

Slereah

13:35

Weitere Studien über das Wärmegleichgewicht unter Gasmolekülen

0celouvskyopoulo7

But I think that's supposed to be a quotient in terms of the algebra, not the vector space

@Slereah Hallo Franz

Maybe I want it to be a quotient wrt. the vector space structure

Has to be

$S^{d-1}\cdot S^{d}\subset S^{2d-1}$

Balarka Sen

@0celouvskyopoulo7 Is $S_n^d$ the space of polynomials of degree $d$ with $n$ variables? Define a map $S_n^d \to H_{n+1}^d$ (latter the space of homogeneous polynoms) as follows. If $P(x_1, \cdots, x_n)$ is a polynomial, send it to $X_0^d P(X_1/X_0, \cdots X_n/X_0)$. That's a homogenenous polynomial of degree $d$ and $n+1$ variables.

Maybe fiddle with that somehow.

0celouvskyopoulo7

@BalarkaSen I think it's much simpler. You just drop all of the terms of degree $<d$ to get $\tilde p$, and this is equivalent to saying that $p-\tilde p\in S^{d-1}_p$.

So $H^d_p=S^d_p/S^{d-1}_p$, where you do the quotient in the sense of vector spaces

Balarka Sen

Ah. A bit uninspiring though.

Breaks my heart.

0celouvskyopoulo7

It's poorly written. They say that $S^d$ is a $*$-algebra, then take a quotient. I thought the quotient was in the multiplicative sense.

Balarka Sen

13:48

Yeah it's a dumb quotient

0celouvskyopoulo7

@BalarkaSen It's a formal way to say "leading terms" of a differential operator

Balarka Sen

Gotcha.

bolbteppa

14:13

@Qmechanic competition on your proof math.stackexchange.com/a/2326882/82615

Obviously Cart-Iwasawa is just Maschke in disguise, who could miss such a thing

John Rennie

@heather I try to entertain - not always successfully of course :-)

heather

@JohnRennie, oh, that was you commenting?

no, I meant Bob Knighton's comment

John Rennie

Ah right. Yes, I agree :-)

heather

> Unless your puberty has been delayed by you moving at relativistic speeds your whole life, I think you will get a far better response (as well as answers from experts) from Health.

John Rennie

:-) I'm pleased the comments have been basically kind. The poor chap has obviously posted on the wrong SE and is probably feeling pretty embarrassed right now. A cruel comment wouldn't help.

0celouvskyopoulo7

14:20

link?

Balarka Sen

It could also be troll.

John Rennie

@Fawad The field can be written as a function of $x$ i.e. $E = f(x)$. The direction of increasing field is the direction in which the $E$ becomes more positive (or less negative).

heather

@0celouvskyopoulo7 physics.stackexchange.com/questions/340024/delayed-puberty

John Rennie

@Fawad: though actually I think your diagram should really say direction of increasing potential not increasing field.

0celouvskyopoulo7

Lol

Grapes

I would think grapes are a decent size, no?

John Rennie

14:27

@JohnRennie We are physicians here, no? — 0celouvskyopoulo7 42 secs ago

Well I'm a doctor :-)

0celouvskyopoulo7

oh, smaller than grapes

I bet European grapes are smaller too

John Rennie

@0celouvskyopoulo7 That's just you Americans boasting again :-)

0celouvskyopoulo7

According to @ACuriousMind we cultivate different grapes

Fawad

14:48

Please don't answer questions that are clearly off-topic. — heather 31 mins ago

Please don’t put water on him. We are doctors not fire fighter

End of humanity.

bolbteppa

@Slereah spin 2 and trace less symmetric tensors?

Slereah

what about it

bolbteppa

Do you see an easy way to link the two

Slereah

That is the graviton field, as it is called

The easy way to prove it is to take the traceless symmetric tensor and to compute its spin

Or use Young tableaux to show that it is the case

The product of two spin 1 fields can be decomposed as a spin 0 field and a spin 2 field

The trace being the spin 0 field

bolbteppa

I've seen a way which copies what you do with gravity waves which seems iffy

Analyzing $h$ in $g_{\mu \nu} = \eta_{\mu \nu} + h_{\mu \nu}$

Slereah

15:00

You can show that traceless symmetric tensors transform under the $(0,2)$ rep of the lorentz group

bolbteppa

I'll check that

Slereah

there's a Thing where you can show that the gravitation field doesn't have the spin 0 part but I forget how to do it

Generally you can always decompose a matrix into an antisymmetric part, symmetric traceless part and trace part

You can show that each of these are irreducible under the Lorentz group

bolbteppa

Trying to link it to $SO(D-2)$

GPhys

hello

Slereah

hey

Things get a lot shittier for SU(3)

GPhys

15:06

watching interesting question and its comments

-5

Q: End of the universe

I have heard of entropy.a doubt araised in my mind that what will happen if I created a machine that spontaneously obtained energy from gravity?does the universe will end? My machine use gravity and spring power alternatively to obtain spontaneous energy

thermodynamics

heather

@Fawad i'm sorry, your meaning isn't quite clear to me.

Bernardo Meurer

Please summer go away

leave me alone

Sir Cumference

@BernardoMeurer waa?

Summer is awesome

Bernardo Meurer

It's almost 40 here

Mithrandir24601

Hayfever's an absolute nuisance though :/

Bernardo Meurer

15:18

I left Brazil to escape these god forsaken temperatures

Sir Cumference

...celsius, right?

Bernardo Meurer

YES

CELSIUS

Jaime Gallego

I heard the Death Valley is lovely at this time of year

Sir Cumference

Dang

Balarka Sen

Summer surprised us, coming over the Starnbergersee, with a shower of rain...

Bernardo Meurer

15:19

And there's a damn forest fire

Sir Cumference

Drink water

use A/C

Bernardo Meurer

@SirCumference I ONLY HAVE BEER

AND NO AC

BECAUSE PORTUGUESE PEOPLE DO NOT PUT AC IN PLACES

ZeroTheHero

@GPhys No point batting that one down any further.

Mithrandir24601

@BernardoMeurer Well then... Isn't the solution super obvious? :P

Bernardo Meurer

THIS COUNTRY IS LOST

heather

15:19

@Bernardo hello

Balarka Sen

But you have a refrigerator right

Bernardo Meurer

@heather Heya

Balarka Sen

Put you and your beer inside the fridge

Bernardo Meurer

@BalarkaSen Filled with beer

@Mithrandir24601 I need to loose my incredibly voluptuous beer chub

Balarka Sen

Kick out some to fit yourself in

Sir Cumference

15:20

@BernardoMeurer Use a...fan?

Bernardo Meurer

@SirCumference I do not own a fan

Sir Cumference

wth dude

how are you alive

Jaime Gallego

Pull one from your graphics card

Sir Cumference

^

Balarka Sen

Pour some cold beer on you

Bernardo Meurer

15:21

Dude here is the list of things I own:
A laptop (Thanks John Rennie!)
A turntable
An Amplifier (Thanks John Rennie!)
Speakers
30-odd records
A bed

bolbteppa

@Slereah seems ok-ish physics.stackexchange.com/a/250016/25851

Bernardo Meurer

@JaimeGallego I do not own any graphics cards lol

Sir Cumference

Didn't know JR was giving away laptops ;-;

Balarka Sen

send me a laptop, JR

Mithrandir24601

@BernardoMeurer Take up martial arts or gymnastics or running or a sport or dancing or some other form of exercise?

Bernardo Meurer

15:22

There was a winter giveaway :P

heather

@bernardo oh, I meant to mention this! I bought myself a turntable, a pair of speakers, and a couple records =D

Sir Cumference

@BernardoMeurer Buy a small fan for $10

0celouvskyopoulo7

@Slereah it's traceless

Bernardo Meurer

@Mithrandir24601 It is warm : |

0celouvskyopoulo7

the trace is the SO-invariant part

Bernardo Meurer

15:22

@heather Nice! Welcome to the club :)

I'll send you a picture of my setup, listening to Chet Baker right now

heather

of course, it was a cheap(er?) record player, but it's still awesome.

Jaime Gallego

My father has a very nice collection of LPs

I cannot carry the turntable around though

There's a store in Madrid with ridiculously cheap records

Balarka Sen

@0celouvskyopoulo7 is that SO

Jaime Gallego

@Bernardo I might buy something for ya

0celouvskyopoulo7

@BalarkaSen @JohnRennie

Mithrandir24601

15:24

@BernardoMeurer I've been told that people tend to be e.g. more flexible when it's warm so are (depending on the exercise) better than when it's winter. Perhaps a better way of putting it is that you don't have to do (quite) as much 'warming up' to a certain extent :P

Balarka Sen

"And we break up our PC's, and yawn, and run to the center of things,
where the John Rennie says:
Boys! Boys! It's a sweet thing (laptop)
If you want it, boys, get it here thing..."

0celouvskyopoulo7

(removed)

Mostafa

@BalarkaSen add https

Balarka Sen

Meh, that did not work. Whateva

Bernardo Meurer

Mostafa

15:27

@BalarkaSen No we can do it

Bernardo Meurer

@heather Kind of janky right now because of moving and exams and so on

@JaimeGallego What do you mean?

Balarka Sen

@Mostafa Huh, didn't know about the https thing.

Bernardo Meurer

@Mithrandir24601 I am the least flexible man on eart

heather

nice @Bernardo

Mithrandir24601

@BernardoMeurer Then taking up (some types of) martial arts, gymnastics or dancing can help improve that!

Jaime Gallego

15:28

5 mins ago, by Jaime Gallego

There's a store in Madrid with ridiculously cheap records

Bernardo Meurer

@Mithrandir24601 I do not do sports that involve sports

@JaimeGallego Oh, missed that message, that's nice! Records here are actually kind of expensive

Mithrandir24601

@BernardoMeurer Excellent, because none of the above are sports!

Bernardo Meurer

I've been trying like nuts to get my hands on King Gizzard and The Lizard Wizard's "Flying Microtonal Banana", but it's impossible to find!

Mostafa

@Mithrandir24601 I practiced Wing Chun for a few months (~5 years ago)

Mithrandir24601

@Mostafa Wing Chun's fun :)

Bernardo Meurer

15:32

I just realized my last message sounds like I'm joking, but I swear it's a real band and that's their latest album!

Mostafa

@Mithrandir24601 For me it was fun when it was just individual practice...before doing any actual fight and stuff...

After that I couldn't continue :)

Bernardo Meurer

They are the geniuses behind The Lord of Lightning vs Balrog

King Gizzard & The Lizard Wizard - The Lord Of Lightning vs Balrog (Official Video)

►

You know it's good when it starts with an epilepsy warning!

Mithrandir24601

@Mostafa Yeah... It took me three months before I managed to actually be able to hit someone in sparring (read: gently nudging them with my knuckles on their chin)

Bernardo Meurer

And they are NOT joking with that warning

Balarka Sen

@BernardoMeurer Headphones on ears rn. You have made me curious.

Bernardo Meurer

15:35

@BalarkaSen You know with me it's always the good shit

Jaime Gallego

@BernardoMeurer Is that a Pro-Ject Debut 3?

Bernardo Meurer

@JaimeGallego Almost, it's a Pro-Ject Debut Carbon Esprit SB

i.e. Acrylic platter and built-in speedbox for 33/45

Speakers are ELAC Uni-fi UB5 Slim

Mostafa

@Mithrandir24601 At the same time, my roommate was practicing MMA ...beating the hell out of each other

I think he had a purple belt

John Rennie

King Gizzard & the Lizard Wizard

King Gizzard & the Lizard Wizard is an Australian psychedelic rock band that formed in 2010 in Melbourne, Victoria. The band consists of Stu Mackenzie (vocals, guitar, flute), Ambrose Kenny Smith (vocals, synths, harmonica), Cook Craig (guitar), Joey Walker (guitar), Lucas Skinner (bass), Eric Moore (drums), and Michael Cavanagh (drums). The band is noted for its energetic live performances and prolific recording output, having released nine full-length studio albums since 2012. King Gizzard & the Lizard Wizard's early work was primarily a blend of surf music, garage rock and psychedelic rock,...

Mithrandir24601

@Mostafa That's definitely not my idea of fun

John Rennie

15:39

Nine albums!

Balarka Sen

@BernardoM Yeah I can see why they give that warning.

Bernardo Meurer

@JohnRennie They make albums like machines!

Balarka Sen

I got close to seizure from the Death Grips footage though lol

Bernardo Meurer

And their last two albums, Nonagon Infinity and Flying Microtonal Banana are DAMN good

@BalarkaSen Death Grips is dangerous shit, my friend broke his fist listening to Giving Bad People Good Ideas

Mostafa

@Mithrandir24601 You're clearly not the martia arts-type person ;) (like me)

strange that you like martial arts so much

Balarka Sen

15:40

Haha you did mention

I like them

Bernardo Meurer

And it was my idea for him to punch the wall when it went crazy :^)

King Gizzard & The Lizard Wizard - Rattlesnake (Official Video)

►

This is their first song I liked

It's basically 8 minutes of a guy saying "Rattlesnake"

I love it

And the video clip is so good

Balarka Sen

I'll check it out in the middle of the night when I'm about to pass out

John Rennie

@BernardoMeurer are you after a vinyl of MFB or just mp3s?

Bernardo Meurer

They got a new album coming next week

@JohnRennie Vinyl, the Flac I can buy off of Bandcamp :P

kinggizzard.bandcamp.com

John Rennie

Ah, that's what I thought you probably meant.

I can see the appeal in owning vinyl records, even though I'm not interested personnally.

I remember, all too clearly, the days when vinyl was all there was - apart from cassette tapes, which were even worse.

Bernardo Meurer

15:46

It's just a neat hobby for me, it's like collecting baseball cards or anything else :P

My Rust code isn't working :(

Cassette sounded nasty af

John Rennie

@BernardoMeurer yes, really compressed and lacking in the high frequencies.

Jaime Gallego

@JohnRennie That sounds strange coming from your generation.

John Rennie

Does it?

Bernardo Meurer

@JaimeGallego His generation listened to 78 RPM Shellacs :P

John Rennie

I wasted hours of my life trying to clean the fluff off vinyl records and trying to clean the stylus. Give me digital music any day!

Bernardo Meurer

15:48

@JohnRennie Exactly! It's great fun

Jaime Gallego

@BernardoMeurer Edison wax records

Bernardo Meurer

I spent an entire day last week carefully cleaning an 80's record that was noisy and poppy as heck

FUN FUN FUN

Jaime Gallego

Edison phonograph cylinders (1888): Handel - Israel in Egypt

►

John Rennie

@BernardoMeurer for a small and rather eclectic subset of meaning of the word fun

Nope. FLACs and a top end DAC will do for me.

Bernardo Meurer

schiit.com/products/yggdrasil

@JohnRennie Go for it :P

John Rennie

15:50

:-)

Actually at the moment I'm using a Mac Mini with the on board audio, and I think it's pretty good.

I don't know what DAC the Macs use, but it sounds fine to me.

Bernardo Meurer

@JohnRennie Oh, come on, treat yo'self

Get a dragonfly at least

Of a Fulla

John Rennie

At the moment I'm listening mainly to Internet radio and Mixcloud, and they aren't good enough quality to make a top end DAC worth it.

Bernardo Meurer

Ewh, internet radio

Treat yo'self

FLAC!

John Rennie

This internet station mostly

bolbteppa

"The spin follows from the fact that the source of gravitation is the stress–energy tensor, a second-order tensor (compared with electromagnetism's spin-1 photon, the source of which is the four-current, a first-order tensor)." hmm

Bernardo Meurer

15:54

Are they the ones that play IDLES?

John Rennie

I'm sure they do play IDLES - they play all sorts of stuff.

I mostly listen to the two prog rock programmes. They used to do a really good punk programme but that has finished.

Bernardo Meurer

You should go to one of their concerts, they're touring the UK :P

I'd go with you, lol

Mithrandir24601

@Mostafa I enjoy martial arts, just not getting walloped on the head :P

Jaime Gallego

'lol' looks like a man drowning

Mithrandir24601

(or in the fingers, or a couple of other places for that matter :P )

Bernardo Meurer

15:56

Out of the fights I want to get into I'm still missing fighting an irish

I managed to fight a Serbian, which was a life-long dream of mine

Mithrandir24601

@BernardoMeurer No you're not

Bernardo Meurer

Now I'm missing an Irish, a Kosovari, and Bosnian

Jaime Gallego

Bernardo Meurer

@Mithrandir24601 Hm?

I am certain I have never gotten in a fight with an Irish man

I would remember that

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