The h Bar

12:01 AM

@dmckee I shot the guy a thank-you and said I'd like to reach out to the NE dept and asked for the name and number of the person to contact

0celo7

12:13 AM

@dmckee He told me to just contact the department head :/

Danu

12:32 AM

I wonder if this is true.

GBeau

@FenderLesPaul I wish I could go tweak minor things on some of mine >.<

ACuriousMind

1:02 AM

@Danu Not really, it is evidently incompatible with entropy in terms of probabilities, i.e. $\sum_i p_i\ln(p_i)$ or $\int p \ln(p)$ since the $p_i$ there are fractions.

Danu

1:29 AM

@ACuriousMind but is one tied to Shannon entropy for thermodynamics?

AFAIK the ln W is completely satisfactory in that context

ACuriousMind

@Danu Hmm? You need the expression in terms of probabilities to define entropy for non-equilibrium (or equilibrium, but non-ergodic) systems

Bernard Meurer

@ACuriousMind Do you sleep?

Danu

I know that

ACuriousMind

@BernardMeurer Sometimes

Danu

But thermodynamics, @ACuriousMind

I find it an entertaining thought that maybe one may not be able to distinguish the correct definition

ACuriousMind

1:34 AM

@Danu I don't recognize thermodynamics as distinct from statistical mechanics. All thermodynamics is is equilibrium statistical mechanics disguising itself by using strange historical approaches :P

Danu

Hahaha, no I don't agree

I think there is no rigorous way of getting thermo from stat mech

But there is a rigorous approach to thermo I think

With the ln as "real" entropy

ACuriousMind

@Danu I'm not following you. What do you think is the difference between equilibrium statistical mechanics for large particle numbers and thermodynamics?

Danu

@ACuriousMind I mean a more rigorous limit

Not just "something something infinite particle number"

Has it been done?

ACuriousMind

It's as rigorous as the "continuum limit", I think. That is, in many cases you can take it, and it is provable it exists, but there might be annoying cases where the limit doesn't (naively) exist

user54412

Just to spur on discussion, can't we have thermodynamics of systems not composed of Newtonian billiard balls?

Danu

1:40 AM

Eh...

ACuriousMind

@ChrisWhite That's statistical mechanics, in my book :P

Danu

Also, it's too late for me to be up

Topology exam is about 40 hours from now :P

user54412

One professor once noted to me that it's a shame people only learn stat mech and not traditional thermo, since practically there exist systems where we don't have a description in terms of large numbers of particles, but we do have empirically valid notions of temperature and so on.

Danu

Since when do people not learn traditional thermo**?

Bernard Meurer

I didn't learn it

Danu

1:41 AM

I know I was forced to

EU > US as usual? ;)

user54412

since ACM took over the curriculum, apparently

Danu

I'm pretty sure ACM must've taken a course on it

Bernard Meurer

ACM took a course on everything

Danu

Neh

Did you have a course on AdS/CFT, ACM? :)

Bernard Meurer

He did

Danu

1:44 AM

In about 1 year's time, I will have :3

(taken a course on everything; I already did the AdS/CFT course!)

In other news, my algebraic topology TA laughed in my face when he heard I was interested in taking the upcoming course on group cohomology. He said "maybe I will take that course" (he's a postdoc)

ACuriousMind

@Danu We did a little bit of thermo in an experimental lecture that was already crammed with mechanics and electrodynamics, but I mainly had stat mech. That might have shaped my view :P

Danu

@ACuriousMind Oh... In Amsterdam there's a mandatory 1semester course purely on thermo

ACuriousMind

@Danu Only on pure CFT

Danu

@ACuriousMind Sooooo boring ;D

JK I think the course on CFT was more interesting than the AdS/CFT one

although it's really nice to have learned what all the fuss is about

CFT is pretty great

ACuriousMind

@Danu It was wonderful, which makes me hate seeing the string theorists butcher it all the more :P

Danu

1:47 AM

I read an old answer of yours on CFT today; neat summary of the first ~50 pages of Blumenhagen

Bernard Meurer

"which makes me hate seeing the string theorists butcher it" That goes along with a bunch of things

Danu

@ACuriousMind OPE OPE OPE OPE COMPUTE COMPUTE COMPUTE

That's what I got out of string theory

(had the exam today...)

ACuriousMind

@Danu Hehe, that was your upvote, then

@Danu Yeah

Danu

@ACuriousMind Yush.

@ACuriousMind And oh yeah also

WHAT IS THE MASS OF THIS STATE?!?!?!

HOW DOES IT DEPEND ON RADIUS OF S^1 DAMNIT!!!

one of the worst courses in the curriculum here

I bet string theory 2 will suck even more

I need it for my thesis prep though :\

0celo7

@Danu Well, how does it

Seems like Kaluza-Klein to me :P

Danu

1:50 AM

@0celo7 Hurr durr self-dual radius massless

0celo7

@Danu NaCl much

Danu

Definitely

So boring!!!

ACuriousMind

@Danu I'm not sure whether they are trying to select for people who enjoy those boring computations or whether they genuinely think they are presenting their field in an attractive manner

0celo7

Pretty sure my PDE prof wants to kill everyone's interest in PDE for life.

ACuriousMind

Then again, QFT is also usually "CALCULATE THIS FEYNMAN DIAGRAM!" for a time...

Danu

1:52 AM

Not at LMU

0celo7

Then there are strange people like my father who think calculating Fourier series after Fourier series is interesting...

Danu

At LMU the professors are way too lazy for that

So we basically do classical field theory

0celo7

The course at my school uses Peskin-Schroeder, so it's probably Feyman diagram season for days

Danu

Yup

0celo7

But I have no intention of taking that course.

ACuriousMind

1:54 AM

@Danu wat

Danu

Welp you can see the Higgsing, the Stueckelberg fields and the dualities

who needs more? :D

The only time we did anything quantum in the past semester of Advanced QFT was, I think, the chiral anomaly stuff

Anyways, I really needda sleep

bye guys

0celo7

@Danu Cheerio.

ACuriousMind

I am certainly no fan of computing Feynman diagrams, but I think you need to see at least a derivation of the LSZ formula and some explicit computations in QED to really understand how QFT works and how it gets its predictions. And it doesn't hurt to do perturbative renormalization so you get an appreciation for the people who actually calculate stuff

@Danu What did you do to calculate it? Triangle diagrams? Fujikawa method? Just abstract A-S application?

0celo7

@ACuriousMind Just like you have to do some tremendous index calculations to get an appreciation for people like @ChrisWhite :)

ACuriousMind

(and good night)

I don't need index manipulations to have an appreciation for @ChrisWhite

user54412

1:59 AM

daww

ACuriousMind

(But I would also say that you need to do indices at some point. I just think they're overused, I don't want to abolish them completely)

0celo7

@ACuriousMind Seriously

What in GR is made clear by abolishing indices

I want your no-nonsense opinion here

Because you HAVE to go to coordinates at some point, anyway

ACuriousMind

@0celo7 I'll give you your weird quantities. That's not a reason to have all the QFT people calculate with indices in flat space

0celo7

@ACuriousMind It's not even weird quantities. It's the fact that stuff like $H_{\mu\nu}u^\nu$ is less awkward than $H(-,u)$.

ACuriousMind

If something is really awkward to express coordinate-free, then don't do it. But I think e.g. electrodynamics and QFT would be a lot more beautiful if they didn't write everything in indices

0celo7

2:01 AM

Beautiful or useful?

Bernard Meurer

Same

0celo7

Not really.

Try building a bridge while viewing mechanics as a flow on phase space.

ACuriousMind

@0celo7 Ah, well, there we disagree. I definitely prefer the latter notation because it makes the relation between the objects more clear - it is H that eats u, and still can eat another vector. I just don't see that in the first version

0celo7

@ACuriousMind I'm sure you know I understand what both notations mean.

ACuriousMind

(And yes, in my mind, forms are gluttons that gobble up vectors)

@0celo7 Of course. They both mean $H(-,u)$ ;)

0celo7

2:04 AM

I taught @BernardMeurer how to urban dictionary :D

@ACuriousMind :P

Bernard Meurer

He did

ACuriousMind

I'm not sure what there is to teach

Bernard Meurer

He taught me it's a thing

ACuriousMind

I'm also not sure whether I want to know

0celo7

Existence and usefulness of UD

My algebra prof has failed the second part for algebra

ACuriousMind

2:06 AM

How can a prof fail their own lecture?

I think I'm not parsing that correctly...

0celo7

I'm not convinced anything we're doing is useful.

My adviser was visibly upset when I showed him my class notes

ACuriousMind

He saw your handwriting, what did you expect? ;P

0celo7

I had him for diff eq last semester...

And you've seen my handwriting. It's pretty good.

ACuriousMind

Note the ";P" indicating that was a joke

0celo7

@ACuriousMind I know.

What's your point?

Bernard Meurer

2:09 AM

Sometimes I feel @ACuriousMind is an AI

ACuriousMind

@0celo7 Thus there is no need to defend youself

0celo7

ACuriousMind

@BernardMeurer Not sure whether that is a compliment, an insult, or something in between

0celo7

@BernardMeurer What do you think?

@ACuriousMind Wasn't in italics, so not an insult.

Bernard Meurer

@ACuriousMind It's not in italic, it's not an insult

Exactly @0celo7

You have the handwriting of a sixth grade girl @0celo7

0celo7

2:11 AM

what the fuck

Bernard Meurer

It's too pretty

ACuriousMind

@BernardMeurer Nah, not enough flourishes

0celo7

:(

Bernard Meurer

On the solution of B) you dun goofed your ramp

0celo7

I'm a girl

Bernard Meurer

2:12 AM

print-screened

0celo7

I will freely admit I'm a girl, no shame in that

user54412

looks like an engineer's handwriting

user54412

also very pretty

ACuriousMind

@BernardMeurer He's said things that are far better to quote at him :D

0celo7

Like what

"I'm stupid"

ACuriousMind

2:13 AM

Oct 22 '15 at 1:12, by 0celo7

I'm a hypocrite

0celo7

I don't think "I like boys" has happened yet...but it might, one day.

@ACuriousMind damn, why did I say that

wow, that's completely out of context

ACuriousMind

@0celo7 Of course, what did you expect? :D

0celo7

Anything else interesting?

Bernard Meurer

I have the hand writing of a first century barbarian from Varusschlacht

ACuriousMind

@0celo7 Of course, but I'm not using up the good stuff now without good reason

@BernardMeurer You're illiterate?

0celo7

2:16 AM

the fuck :D

Bernard Meurer

Also, but that's unrelated

0celo7

@ACuriousMind c'mon

for me

pleeeeeeeaaaaaase

Bernard Meurer

That's mine

In the prettiest it ever gets

0celo7

That's not bad at all

At least you won't be mistaken for a 6th grade girl if someone reads your handwriting 300 years from now...

Bernard Meurer

My teachers used to complain about it being hard to read and not cursive

0celo7

2:21 AM

"Oh my god this 10 year old girl was taking notes on Morse theory"

2

Bernard Meurer

HAHAHAHAHAHA

ACuriousMind

I stopped writing full-on cursive because mine is unreadable to most people

@0celo7 lol

Bernard Meurer

@ACuriousMind Same

ACuriousMind

Someone should encode Milnor's book in Morse code, btw

Bernard Meurer

Get me a pdf

ACuriousMind

2:22 AM

Then you can learn Morse while learning Morse

0celo7

wooooooow

ACuriousMind

@BernardMeurer Ah, that's the problem, it's typewriter

0celo7

so original ACM

Bernard Meurer

Morse is not complex, just boring

@ACuriousMind What is morse theory?

ACuriousMind

@0celo7 Good jokes come from running out of bad ones

@BernardMeurer The art of detecting the homotopy type of a manifold by studying a generic differentiable function on it

0celo7

2:24 AM

@ACuriousMind which person with shitty jokes said that one

ACuriousMind

@0celo7 Not sure whether that's a quote or I made it up

If it's a quote, I don't remember by who

Bernard Meurer

@ACuriousMind Whats a homotopy; whats a manifold; what's a generic differentiable function and what do you mean by 'on it'?

user54412

is this post-your-handwriting club now?

0celo7

@ACuriousMind ok, so you're the person with the shitty jokes :P

ACuriousMind

@BernardMeurer A continuous deformation; a space locally modelled on $\mathbb{R}^n$; any differentiable function but a few ones; "on it" = function from it to the reals.

Bernard Meurer

2:27 AM

@ChrisWhite Yes, go ahead

@ACuriousMind "Continuous" as in infinite?; "Locally modelled"?; but a few ones?

ACuriousMind

@BernardMeurer Do you really want to continue this? :P

0celo7

@BernardMeurer Continuous: preimage of open sets are open

Locally modeled: every point has a neighborhood homeomorphic to an open set of $\mathbb{R}^n$

Bernard Meurer

@ACuriousMind I always want to learn stuff, but I also don't like pestering people so it's entirely up to you :)

0celo7

excluding the few that have a degenerate Hessian (I think)

Bernard Meurer

preimage of open sets?

ACuriousMind

2:32 AM

@BernardMeurer That's fine, but you won't learn stuff if I just explain words you don't know with words you don't know, and I won't improvise an intro to topology and analysis right now

Bernard Meurer

@ACuriousMind I have a theorem that if we go for long enough it will just be the four basic operations

That can take years tho

ACuriousMind

In the end, it's all set theory (or type theory).

Bernard Meurer

No you got it wrong

In the end it's all magic

user54412

bit out of focus it seems

0celo7

2:37 AM

wtf is that

Bernard Meurer

That's a badass handwriting right there

0celo7

looks like geometry/calculus

GR stuff?

ACuriousMind

My board writing is bad

user54412

mmm, this was a warmup in normal spherical coordinates

user54412

didn't want to bother writing it all out in Kerr

Alfred Centauri

2:54 AM

@busukxuan "Mind if I ask a short question?" is a short question.

FenderLesPaul

@GBeau tweak what?

Bernard Meurer

Wow, that took a while to respond to huh @AlfredCentauri?

@HDE226868 How's the chamber going?

@FenderLesPaul Show us your handwriting

HDE 226868

@BernardMeurer Not yet started.

But midterms are done, so my free time just tripled.

FenderLesPaul

@BernardMeurer haha alrighty

Bernard Meurer

@HDE226868 I want to see them particles

HDE 226868

2:58 AM

@BernardMeurer I'll see if I can post pictures if we get good tracks.

Bernard Meurer

@HDE226868 :)

HDE 226868

But that won't be 'til May or June. I do have to actually finish the rest of the course.

One more unit, then AP review.

GBeau

@FenderLesPaul just minor wording and things QQ

FenderLesPaul

Ah

Gotcha

GBeau

3:15 AM

@FenderLesPaul did you have to do a personal history statement for ucsb

0celo7

3:56 AM

@ACuriousMind I can't get the chalk to not make this horrible squeaking noise

Denzler has banned me from writing my thoughts on his board when we're talking

dmckee

@ChrisWhite If that's your work I admire your neat sketching. Well done.

0celo7

4:11 AM

@dmckee My sketches are a lot better.

dmckee

@0celo7 The question is how are they when done in front of a class?

GBeau

my handwriting significantly improves in front of class

which is better than the other way around

0celo7

4:24 AM

@dmckee never done that

0celo7

4:45 AM

why can't I star my own stuff

there's something satisfying about closing 20 tabs

Oct 22 '15 at 1:50, by 0celo7

I can't stop thinking how handsome my avatar is

What was my avatar at the time...

FenderLesPaul

5:06 AM

@GBeau yeah I did

I wrote about my high school and tutoring and minorities

GBeau

@FenderLesPaul I had to write one for UC Irvine

it ended up being a couple of really bad paragraphs

but I guess it didn't matter because I got in

FenderLesPaul

I think all the UC schools make you do it

but I don't think they care about it at all

it's just like a formality

Is Stonybrook your top choice over UC Irvine?

GBeau

between the two?

probably

FenderLesPaul

yeah between the two

GBeau

a week from today is going to be pretty big

FenderLesPaul

5:11 AM

why?

GBeau

I just mean that's when a lot of schools have sent out historically

a week from today

FenderLesPaul

oh I see

yeah fair point

although at this point I can finally stop checking my emails frantically and being anxious

because UCSB was my top choice

anything in addition to this would just be icing on the cake

GBeau

qq

FenderLesPaul

whaat

why qq?

GBeau

waiting

seeing other ppl get in

FenderLesPaul

5:25 AM

@GBeau ah, yeah I feel ya

@0celo7 is there anything you want me to relay to Polchinski or Srednicki on visit week?

:p

Danu

8:19 AM

@ACuriousMind All that stuff was just done in exercises for us :P

Secret

8:32 AM

Fun fact: Dmckee has a user ID (according to stack exchange search bar) that happens to be last year

yuggib

9:08 AM

@0celo7 Math and GDP:

arxiv.org/pdf/1602.01423v1.pdf

it has literally the acronym GDP in the second line of the intro

Secret

yuggib, what's your view about an economic model known as steady state economics?

Slereah

hey

Obviously the correct model is accelerated inflation economy

Because of dark money

Heyooooo

Secret

9:23 AM

Uh, I am not making a joke or anything. The thing is, I am kinda aware there are many economic models. Recently in a talk I learnt about a model called steady state economics. I am just wondering how it compares with other models like what are the pros and cons on using them?

Slereah

Ask economists, maybe

Secret

The response just a few lines above is the reason why before realising economics has a non human factor, I often refrain from asking economics questions, because people tend to start thinking about money and corruption, and then turned the question into a joke

ok

Secret

9:43 AM

5

Q: Is indefinite exponential economic growth possible?

Economic growth is frequently expressed as a % of GDP. Proponents of a steady-state economy postulate that perpetual exponential economic growth is impossible and that any system relying on it is inherently unstable. Is this true? Is indefinite exponential economic growth possible? (See also: ...

growth

Only one question on this topic
Now searching for other questions that talked about various models

7

Q: Are there fundamental reasons why (exponential) economic growth is highly desirable?

One of the most widely published measures of the economy is the economic growth as a % of the GDP; i.e. the degree to which an economy grows exponentially. In my understanding, when the rate of economic growth is declining or close to 0%, this is considered undesirable and acts are undertaken to...

growth

The user of this question, seems biased towards non growing economy

2

Q: Why economic models have no profits, unlike the real world?

I'm puzzled by the core example of an economy populated by firms with a constant returns to scale production function operating under perfect competition, where no income remains after paying out competitive wages to workers (L) and competitive return to the capital hired for production (K). Mean...

economic-terms profits

understanding profits

12

Q: Topological concepts in economic theory

QUESTION: What are the major or systematic applications of post-1960s mathematics to microeconomics? For example, in the late 19th century, Fisher first used the mathematical ideas of Gibbs to construct modern utility theory. In the 20th century, Mas-Colell incorporated topological ideas to...

microeconomics mathematical-economics decision-theory bounded-rationality welfare-economics

I am interested in anything that does not reminds me of corruption and impassiveness

Secret

10:06 AM

Ecological economics

Ecological economics/eco-economics refers to both a transdisciplinary and interdisciplinary field of academic research that aims to address the interdependence and coevolution of human economies and natural ecosystems over time and space. It is distinguished from environmental economics, which is the mainstream economic analysis of the environment, by its treatment of the economy as a subsystem of the ecosystem and its emphasis upon preserving natural capital. One survey of German economists found that ecological and environmental economics are different schools of economic thought, with ecological...

interesting...

Danu

More interestingly, Pastafarianism is now an official religion in my home country :)

Secret

what will that implicate?

Danu

That one may wear a colander on his/her head for a passport photo now.

Secret

nice

Danu

10:54 AM

Any reason why this should not be deleted?

7

A: Number theory in Physics

I recall being stunned (they can do that?) by the mere mention of the technique called "Zeta Function Regularization", see http://en.wikipedia.org/wiki/Renormalization, http://en.wikipedia.org/wiki/Zeta_function_regularization , to sum divergent series like zeta(-n) to get finite results. I tho...

0celo7

12:56 PM

@FenderLesPaul No, but I probably have something you can ask Zee about

0celo7

1:35 PM

@Danu And you people call me the troll...

@yuggib VERY GOOD

Nice to see that mathematicians are finally spending their time wisely. Now if only those pesky algebraic geometers and number theorists got their shit together...

@Slereah heh

Transcript for