The h Bar - 2024-05-01

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12:58 AM

For the canonical ensemble of a hydrogen atom transitioning from state $s_1$ at $-13.6eV$ to a degenerate state $s_2$, at $-3.4eV$, Schroeder says $$\frac{P(s_2)}{P(s_1)} = \frac{\Omega_R(s_2)}{\Omega_R(s_1)}$$ I have an issue with a part of the reasoning

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I might be wrong, but I thought the combined system's multiplicity is $\Omega_A\Omega_B$ for coupled systems $A,B$ which would mean since $s_2$ is degenerate, you'd have $\Omega_A\Omega_B = 4(50)$ for $s_2$ and $1(100)$ for $s_1$

so actually $s_2$ is more probable.

I guess it's still logically sound minus that one part

The sum of the combined multiplicities equals the total multiplicity of the system. $$\sum_i{\Omega_A(s_i)\Omega_B(s_i)} = \Omega_{total}$$ $$P(s_i) = \frac{\Omega_A(s_i)\Omega_B(s_i)}{\Omega_{total}}$$ I think

2 hours later…

2:58 AM

something i'm mulling over. in the hydraulic-electrical analogy, a (electric) capacitor is analogized to a (hydraulic) accumulator. There's a few ways to build such an accumulator, but one is to use a flexible diaphragm

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this makes me think of the pressure difference inside/outside of a balloon, and thus of the two-balloon experiment

where you connect two balloons with different volumes and see that the air will flow into the larger one

what i'm trying to suss out: what would be the electric circuit equivalent?

(there's limits to the hydraulic analogy, so it's possible there isn't a reasonable comparison here)

@Semiclassical The air flows into the larger one because the elasticity increases as $V$ does, right? For circuits, adding a capacitor kind of adds another battery/emf (once it's done charging)

but I think to compare it to the two balloon experiment you'd remove the battery/constant supply emf and put another capacitor in its place

or something of that nature

actually I have no idea lol because capacitors do not complete a circuit

unless this does make sense

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I think the charge would redistribute in such a way that reflects some properties of the capacitors

1 hour later…

naturallyInconsistent

4:32 AM

@Obliv you are correct. But any author has to cover the simpler case first. The H atom is just a horrendously bad choice for Schroeder. Everybody else chooses QHO first. What he means is that he is considering the microstate of the H atom, so no multiplicity of the degenerate macrostate of the H atom yet.

5:12 AM

yeah that's confusing because I thought $\Omega_R(s_1)$ meant the multiplicity of the reservoir with a given energy from the atom in $s_1$ but it seems to mean something else..

or rather it is the leftover energy of the system if the atom occupies $s_1$

or perhaps that is what it means but then the combined system is just that figure since $\Omega_A(s_1)=1$

where $A$ denotes the atom

in any case, $\Omega_R(s_1)$ is the number of accessible microstates to the reservoir when the atom is in $s_1$. Thus the combined system is $\Omega_R(s_1)(1)$ since there is only one microstate $s_1$ which the atom is occupying

So we can consider the ratio of accessible microstates of the reservoir to reflect the probability of the atom being in a given microstate

ill think abt that part tomorrow time to slumber

meow

@Semiclassical With a capacitor voltage (pressure) ∝ charge (air in balloon)

But for balloons the pressure is not proportional to the air in the balloon, so the analogy fails.

naturallyInconsistent

M I A O ~

5:43 AM

Star spam here too?

@Qmechanic

6:26 AM

@DannyuNDos Thanks for the heads up - fixed now.

6:54 AM

@JohnRennie : Thanks for the clean up.

1 hour later…

8:19 AM

In GSW (chapter 1, sec. 1.4) they say that the Hamiltonian of a nonrelativistic particle of mass $m$ in $n+1$ dimensions is $p^2/2m=\Box/2m$. What theory is this, though? They use the D'Alembertian, so that is the 4-momentum and yet they call it the Hamiltonian of a non relativistic particle?

The Hamiltonian of a non relativistic particle should only involve spatial derivatives

(When I said 4-momentum I meant $n+1$-momentum :P)

8:42 AM

Also it's /2m which is the non-relativistic case yeah

Maybe he's just using the box in general

8:54 AM

@Mr.Feynman does this matter at all for anything in the rest of the text? :P

people are sloppy when writing down formulae, especially when they are intro fluff whose exact correctness doesn't matter for anything else

Not quite, I moved on

the following eq. (1.4.2) is correct and that's all that matters

Yes, seeing that the following equation was correct made me wonder if I was missing something

But yeah, I'm also rushing this chapter

Subsequent chapters look much easier

I wouldn't say "easier" :P

the first chapter is just not written as an in-depth textbook, it's just fluff

so if you read it as if it were a detailed, careful account like you expect the rest of the book to be, you're going to have a bad time

you would lose nothing except some historical context by just starting with chapter 2

@ACuriousMind *reader-friendly, then

Like the way the jump from the fact that external string quantum numbers are preserved to operator-state correspondence is sorcery

But if I understand correctly, this is like a more general version of the correspondence $a^\dagger_k\leftrightarrow\lvert k\rangle$

9:43 AM

you can skip the first chapter of most books really

that's where the author feels obligated to write an introduction

2 hours later…

11:53 AM

hi

what r u learning currently

@Slereah Weinberg's historical introduction in his QFT book is better than the whole book

It depends on the book

12:20 PM

do u think a new theory of physics cud possibly make free will possible

1 hour later…

1:36 PM

shud we constantly visualize while learning things

1 hour later…

2:49 PM

@Mr.Feynman I think if you replace the word non-relativistic with relativistic then it makes sense, where they ignore the constant term in the $e$-gauge-fixed relativistic point particle action

i.e. they use $S = \frac{1}{2} \int d \tau e(e^{-2} \dot{x}^2 - m^2)$ with $e = 1$ and $\tau \to \tau/m$ and $m=1/2$

So that $S = \frac{m}{2} \int d \tau (\dot{x}^2 - 1)$ and with $\tau' = \tau/m$, the Hamiltonian is just the constraint so from (the $e=1$ gauge-fixed action) $S = \int p dx - H' d \tau' = \int p dx - \frac{1}{2}(p^2 + m^2) d \tau' = p dx - \frac{1}{2m}(p^2 + m^2) d \tau$ we get $H = \frac{1}{2m}(p^2 + m^2) $ something like that

3:18 PM

@bolbteppa isn't that $=0$ given that $p^2=-m^2$? After all the relativistic Hamiltonian is zero, isn't it?

That is a primary constraint, using Dirac's method we add primary constraints to the action etc

Basically, making sense of this action and its Hamiltonian is a good enough motivation to learn the basic idea of Dirac's method

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Can someone help me understand the logic in going from $6.7)$ to $6.8)$

I think this happened with the adiabatic expansion/compression formula which I didn't immediately pick up on either

I wanna know what's happening here mathematically :\

3:40 PM

If $f(x) = f(y)$ for all $x$ and $y$, then e.g. $\partial_x f(x) = \partial_x f(y) = 0$ and $\partial_y f(y) = \partial_y f(x) = 0$ so that $f(x) = f(y)$ is a constant, $f(x) = C$. Since $f(x) = P(x) e^{E(x)/kT} = C$ we have $P(x) = C e^{-E(x)/kT}$, and $1 = C \sum_x e^{-E(x)/kT} = C Z$ implies $C = 1/Z$ so that $P(x) = (1/Z) e^{-E(x)/kT}$

in general are energy functions $E(s)$ and probability functions $P(s)$ "constants"?

(or if you prefer, $f(x) = f(x + c - x) = f(c)$ for $c$ a constant so that $\partial_x f(x) = \partial_x f(c) = 0$)

That does not follow from this argument

oh so the $f(x)=f(y)$ is a constant is just an example hence e.g.

Can I just construct the partition function without $\frac{1}{Z}$

and then it would follow anyway?

naturallyInconsistent

@Obliv necessary to normalise.

3:56 PM

so $Z$ is the sum of all the boltzmann factors. $$P(s) = \frac{1}{Z}e^{-\beta E(s)}=\frac{e^{-\beta E(s)}}{\sum\limits_i e^{-\beta E(i)}}$$ where $i$ are states

idk why I wrote that. I gotta play around with this more to get a better understanding

Claudio Menchinelli

4:24 PM

if u want to work with a probability density function you necessarily need to impose the normalization condition

as @naturallyInconsistent said above

it's one of the fundamental axioms if Im not mistaken

in your case it is easy to see why you have the sum over all possible states in the denominator

@Obliv I don't think I understand your question, but at first sight it doesnt seem to be a correct conclusion :P

4:37 PM

Weinberg particularly values historical knowledge of physics so perhaps his introduction is a genuine introduction hehe

Why should time orientability have to do with allowing spin structures in one’s physical theory 🤔 (physically not mathematically)

@SillyGoose what is a spin structure "physically"? :P

Claudio Menchinelli

hahahah got him

Maybe allowing the existence of things modelable by spinors?

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physical spinors?

@SillyGoose no, my point is: Do you have a "physical" explanation of what a spin structure even is? Most physicists just write down spinor fields and never bother discussing spin structures as a concept at all :P

4:50 PM

@ACuriousMind i do not either:P but i think i mean to ask why should time orientability be tied to even allowing fermions into the physical theory, fermions being a more familiar physical idea

@SillyGoose essentially, time-orientability is needed to have a global consistent choice of SO(1,3), just like orientability in the Riemannian case is needed to have a global consistent choice of SO(n) - the reduc

5:39 PM

Basically if you have spinors on such spacetimes, you can have spinor fields on a given patch of it, but if you try to match them all together, you'll end up finding out some of the components pointing in the wrong direction

You can have more general objects that are spinor-like but they're not proper spinors

This is similar to how orientations work and they are kind of the same type of structure

is multiplying by $\exp(S_{\text{total}}/k_B)$ the same thing as $\frac{1}{Z}$, dividing by the sum of all the boltzmann factors?

6:01 PM

nvm I think the left side is just the inverse of the right

@bolbteppa I agree but I must survive without it now :P

I need help with notation. Okay suppose I have a weakly coupled system $AB=A\cup B$ where $A,B$ are respective phase spaces of each system and they can exchange energy which is fixed $U = U_A+U_B$. The microstates of $A$,$B$, and the combined system $AB$ are points in their respective phase space, where if $U_A(A(s_i)) = E_i \iff U_B(A(s_i))=U-E_i$

I wanna express that last statement better, I just want to say that $U_B$ depends on $U_A$ for a given state that one is in

6:29 PM

nvm

I'd want the indexed union of that not cartesian product

I think I recall we needed particles to be indistinguishable in some microcanonical ensembles, does this follow for canonical/grand canonical?

@SillyGoose I'm not sure about this kind of physical argument really excludes spinors, because we are only excluding finite dimensional spin reps via topological arguments:

7

Q: Does $\operatorname{GL}(N,\mathbb{R})$ own spinor representation? Which group is its covering group? (Kaku's QFT textbook)

In Kaku's QFT textbook page 54, there is a saying: $\operatorname{GL}(N)$ does not have any finite-dimensional spinorial representation. This implicates that $\operatorname{GL}(N)$ owns infinite-dimensional spinorial representation. While in my opinion, a group's spinorial representation is the...

group-theory representation-theory lie-algebra

(This seems to be a good example of where abstract math is essential)

@Mr.Feynman Learning it is a game changer, one of the more useful things

Prof. Rabin Banerjee - Pedagogic Introduction to Constrained Dynamics 1 - 11.09.14

Are pretty good

7:36 PM

@bolbteppa mhh 5 short videos only, huh? Looks like I don't need to read QoGS for the time being :P

7:56 PM

Use that and Dirac's little book, you see there are tons of reviews of it there

if anyone wants some free rep

@JohnRennie i take your point, though i'd push back slightly: the diaphragm example shows that there are cases where the balloon pressure is proportional the air in the balloon. but that's not the geometry in the two-balloon scenario

i think in the context of the 2-balloon experiment, what i'm talking about is the LHS of this picture whereas the usual scenario is entirely on the RHS:

8:20 PM

does anyone have a recommendation for a calculus textbook for reviewing material out of?

I liked larson

i can send it to u if u want (though if u just google "larson calculus" you'll find it pretty quick..)

Nikolai Piskunov

Nikolai Semenovich Piskunov (Russian: Пискунов, Николай Семенович) (9 May 1908 – 1977) was a Soviet mathematician working mainly in the field of partial differential equations. He is known for the Kolmogorov–Petrovsky–Piskunov equation, a key model in mathematical population dynamics, and his textbook on differential and integral calculus which was used at many technical universities and was translated into several languages. == Life == He was born in Froltsovo (Ivanovo Oblast) and graduated from Yaroslavl State Pedagogical University in 1929. He received his Doctor of Sciences in 1939. From 1941...

> He is known for... his textbook on differential and integral calculus which was used at many technical universities and was translated into several languages

@Obliv i can find it in the library of genesis

@bolbteppa thanks

there's a pdf in like the 2nd google search result for me xD

Again you see multiple glowing reviews

8:23 PM

library of genesis is great

can I literally just add in the gibbs factor in that derivation I did :P for the grand can. ensemble

instead of throwing it out when going from $S_B(s_i)/k_B = U_B(s_i)/k_BT$ just include it so $S_B(s_i)/k_B = (U_B(s_i)+\mu N_B(s_i))/k_BT$

8:52 PM

wait so the CE is for a heatbath and a small system that don't exchange particles, the GCE is for a heat bath that can exchange particles with a small system as well as energy (again with fixed temperature?), and MCE is for coupled systems that can exchange energy (idk what else to say about this one)

the examples we covered for mce is 2 state paramagent, einstein solid, and one other I'm forgetting

ok so difference is Mce specifies a fixed total energy for the macrostates whereas ce,gce uses information about energies/number of particles of the smaller system to assign probability for the whole system to occupy that state

i don't really understand this whole time thing

oh man I missed something in my derivation. I can't just say $S = \frac{1}{T}U_B$. the way it's supposed to work is the difference in probabilities of two macrostates of the combined system amounts to the difference in the mult. of the reservoir which is tiny so then u can invoke the therm. identity..

@SillyGoose time is pretty freaky man

like okay we develop physical theory and it should match with empirical data. okay there are things that behave like fermions in the world and we can verify it. but it does not seem like time is something we empirically verify

we do not measure time, we construct devices that keep track of the human construction of counts, which we call time

but then why should this very human construction be thought of as part of this fundamental spacetime manifold underlying the world

Actually we should be following canonical time aka god's stopwatch

right @Slereah

9:07 PM

well maybe i mean to draw attention to: we seem to be treating spacetime as more fundamental than the objects that live on it, e.g. spinors. but then...we are using the existence of fermions to constrain the behavior of time?

i get we always are working backwards to obtain a better theory of things, but this seems absurdly backwards

I don't understand what you mean there

well i think i don't really understand why you would take time to be orientable in the first place

why model time as this real-valued parameter $t \in \mathbb{R}$

time as a phenomenon doesn't even seem orientable necessarily. i mean how would you even formalize that as an observation

@SillyGoose is your experience of daily life not that there is a future and a past and you can use a number to describe how far in the future and the past events are?

well the real numbers are completely ordered, but time i don't really have any expectation to be

i get that it is maybe a naive guess at what time could be based on what we know and experience

and it seems to be a useful definition of time

and is it not also the case that given two events along your experience it is not possible that someone else sees them in the reverse order?

9:12 PM

is time the thing light is trying to minimize while crossing space?

well now that's philosophy :P

@SillyGoose no, this is literally what time-orientability models

well why a person though

what about a caterpillar

if the manifold is time-orientable, you can choose an unambiguous orientation so that all observers agree on what's in the future and what's in the past relative to a given event

even for another person i don't really have a genuine reason to believe that that other person at the least experiences time in the same way i do

but of course that probably leads to a very nasty and very useless physical theory

9:14 PM

@SillyGoose what about this is related to how someone "experiences time"?

you can give anyone a clock and tell them to label events by what the clock shows

I'm having enuf trouble digesting the consequences of SR and now this goose is honking about potential theories where time isn't even well ordered

rip me

time-orientability means that you can choose all clocks everywhere such that two events that are time-like separated for one observer and one is later than the other then are seen as "one later than the other" by everyone else

@Obliv i don't even mean to talk about relativity :P but the proclaimed properties of spacetime is kind of interesting

non-time-orientability gives you weird stuff like CTCs

what is CTCs?

9:16 PM

Closed Timelike Curve

time travel, essentially :P

Oh so how in general moving ref. frames aren't synchronized then time orientability means u can calculate by how much sort of?

@ACuriousMind but what really is meant by a clock

to me a clock is a counting device of some sort

@SillyGoose it's a thing that measures time, just like rulers measure space

in relativity you usually construct light clocks

Yeah, some measure by pendulums, others by radioactive decay, some by lasers, etc

but how can you really be given a "clock", whose definition as stated above relies on time, when we're trying to consider the properties of time in the first place

or like we don't know what time is in the first place

9:19 PM

I'm sure @Slereah will be happy to refer you to hundreds of sources that discuss the difficulty of building up measurements from the raw foundations in relativity

like how am i supposed to experimentally observe an anyon if i don't know what an anyon is (and recognize it, too)

@SillyGoose how does any physics work at all?

well yes that is true as well it really has no good reason to work at all

at least to me

@ACuriousMind it indeed sounds like quite a thorny problem

I think from a philosophical descartes pov, time is what u call it and choose to believe it to be

well that is what it seems physics is saying

define time to be X. define space to be Y. these have properties Z. end of story

it is the starting point that always is not consistent with the actually framework of the thing

because else you cannot start and make anything useful out of your ideas

9:23 PM

I dont follow

I mean, this is kind of the reason philosophers like Kant put time and space as a priori intuitions - notions not derived from any experience at all, but necessary pre-existent intuition through which interpreting our experience becomes possible at all

@Obliv it seems in any framework one constructs you must begin with a leap of faith. because it is too difficult or impossible to really reasonably construct a consistent theory that is reasonable from before starting to end

no physical theory "defines" what it means by time, not really

time is what clocks measure, space is what rulers measure

the value of the physical theory is if you apply it as if the numbers on your clock in the lab are time and the numbers on your ruler are space, you get correct predictions

it's job isn't to convince you the clock really measures "time" in some absolute Platonist sense

@ACuriousMind i do like this as the starting point of human experience, but then it puts a blow to physics and science as just being anthropocentric i feel. or, you've got to convince people that "even though we must see as humans see, we can really see into the depths of the objective world!"

I don't think we see the "objective" world at all :P

all models are wrong, some are useful

9:27 PM

i suppose agnostic is the reasonable stance

but i mean if everyone was born amnesiac, then our physical theories would just be utterly different

@SillyGoose why would they? there's plenty of instances of different people coming up with similar ideas about the world in different places

well maybe we wouldn't have physical theories at all lol

I had a similar thought but for being blind and or deaf. I reasoned that we'd still be able to make the same theories off touch alone but it'd be highly involved.

i mean literally if everyone in the world had short term memory

many ancient cultures developed an understanding of the heavens and similar mathematical models for the motion of the stars; not all of these cultures had contact with each other

9:30 PM

But if u throw away all sense then yeah idk. It'd be like the put monkeys in a room and leave them with a typewriter bit. Maybe thats what earth was lol

science isn't a fluke just because it's not the absolute truth

well i don't think science is a fluke it is just all we got

@SillyGoose but your claim that we might just come up with entirely different theories if we forget all the current ones sure sounds like that!

but i just mean to observe that science and its accomplishments seem very sensitive to the beings doing the science. as Obliv gave a more clear example, an absence of one or more senses we are accustomed to. or an absence of memory in my case

@ACuriousMind more like no longer had the capacity to develop theory

via an inability to construct continuous chains of thought

Does it concern u that what we've developed so far in science is highly subjective :D?

9:33 PM

even if you could write out all you've thought through, if your memory lasts like 5 minutes you could only reabsorb 5 minutes worth of reading

@SillyGoose I think this is an overreaction to the whole time thing :P

subjective in the sense that it applies to humans who can read understand and verify it

@Obliv well subjective and objective are very sketchy words i feel

yeah i use them loosely but they have more technical definitions in the context of philosophy

like what is good and what is evil. there is a colloquial sense but who cares about the colloquial sense if you're trying to make a precise statement

9:35 PM

you seem to think that it's perfectly plausible to imagine beings with no concept of time and no concept of the past and the future; I disagree - however their internal experience of "time" looks like, if they're doing science they will have something equivalent to our idea of initial conditions and time evolution, simply because you need to understand that you need to build the bridge before you drive the truck over it and not after to do proper engineering

@SillyGoose i guess we ought to pay more attention to what we can intuit/feel than simply follow logic ;) since we're multifaceted

maybe the alien physicists use anti-hermitian generators and the alien mathematicians use hermitian generators...

well i think the problem is just the question of how other things see other things is impossible to answer :P

@ACuriousMind What about an electron? (half kidding)

I guess u still need t in qm

well this is a sillier example, but more concrete, you could perhaps just have a being that exists in some subset of what we call spacetime at once and that's just how it is

a static life where nothing happens under our framework

like a painting in the actual sense like frozen in time lol

9:39 PM

@SillyGoose maybe this exists, but why worry about it? In what meaningful sense is that a "being" from our POV?

beings so alien that they don't even share our notions of time and space are Lovecraftian Outer Gods - you shouldn't try to understand them since you usually end up eaten by a five-dimensional dog or some shit

it is just interest i suppose :P. but i could only see justifying the focus of science by the observation that there are just far too many other things that could be interesting. which is fine justification, but it is no search for truth nor a reasonable decision (there seems to be no reasonable decision).

continuing my line of thinking from above: to get something like the two-balloon experiment for circuits, you'd need a nonlinear capacitor whose voltage initially increases linearly as a function of charge but then eventually starts starts falling beyond a maximum charge

@ACuriousMind if you send your data back in time maybe you get a nice PRL letter ;)

or maybe a box of classical particles in a specific macrostate in phase space. Those beings "exist" at a given "time". maybe time is like an infinite array of doors which lead to different possible universes and our experiences are just going through a certain set of then in sequence

aight i should prolly keep cramming for finals

@Obliv maybe they will ask you what is time on one of your finals

9:43 PM

I hope not, I'll just draw a goose

@SillyGoose but see - it doesn't matter if there's some weird being that doesn't see time as I do for all the statements about why time travel is impossible: Using a different definition of time doesn't suddenly make time travel by our definition possible

@Semiclassical You probably want a capacitor whose plates are positively curved towards each other then

it is true but it might shed light on (~thinking platonically~) a "better", or more weakly, another definition on time that is a synthesis of our two definitions

if you get a case where your data from the future appears in the past that's a CTC by our notion, and it's hard to find "acceptable" spacetimes that allow for this

maybe. i'm more used to thinking about non-ohmic resistors than nonlinear capacitors

9:45 PM

it is like we are one physicist who thinks in one way and constructs a theory. if we can then have conversations with another physicist or mathematician or whatever who thinks in another way we collectively get a better idea for an "improved" theory

although it might be pretty hard to communicate if one person speaks english and the other japanese...

I would worry about communicating scientific ideas to eldritch beings after we've figured out how to communicate them effectively among humans :P

Lol

another problem with no solution

that would be a nifty dissertation: "How to talk to people"

that's called "communication theory" and is an actual discipline :P

Can't we just use an ambassador

working in terms of energy might be easier. the surface energy of a balloon is proportional to volume^2 at small volume but volume^(2/3) at large volumes

9:50 PM

I nominate ACM he is both a mod and an AI sent from the future

@ACuriousMind maybe i should read some of this communication theory...

@Obliv unfortunately it turns out we mistranslated the alien word for "ambassador" and informed them we had sent a sacrifice instead

so need a capacitor whose energy scales as Q^2 for small charges but Q^(2/3) for large charges

LOL. that sounds like a line from star trek or something

XD

9:52 PM

@Obliv Temba, his arms wide

there's a famous episode of TNG - "Darmok" - where they meet a species where their universal translator fails because they communicate entirely in metaphor and mythological references

@Semiclassical what is surface energy of a balloon? Like the potential energy of the elasticity as a function of volume?

right

so while they can translate the literal words being said, that doesn't help because half of them are proper names and all of them only make sense if you share a cultural background

Lol, so the word for ambassador translates to mean sacrifice

also i think my interest in this time thing is a more general interest in trying to figure out how to assess which assumptions of Physics are reasonable and which are not.

10:01 PM

@Semiclassical I haven't derived capacitance/energy of a capacitor of shape other than two flat infinite plates but I imagine this would require some tricky calculus

Or maybe not. The end goal is having a nonlinear (and not just quadratic as in two infinite plate case) energy function

I guess one way is to start with the solution u have of the balloons and work on trying to model the capacitor in that way

yeah

10:38 PM

@ACuriousMind Oh, I get it now Sokath, his eyes open!

user image

this seems incredibly low

on average 5.6 out of 1 billion atoms (in the ground state) around the surface of the sun is in the first excited state?

wait what there's iron, magnesium, etc in the "solar atmosphere"? wat

user image

i thought the sun was like all hydrogen,helium and other really low atomic number elements

11:25 PM

it's mostly that, but it'll keep fusing until it stops being energetically favorable

iron is the tipping point

see hyperphysics.phy-astr.gsu.edu/hbase/Tables/suncomp.html

the one which confuses me tbh is sulfer

@Obliv hmm, this article poses it more in terms of the residue of earlier stars : astronomy.com/science/why-is-there-iron-in-the-sun

Yeah that's more of what I'm familiar with

That our star system is 3rd generation+ or something

right

But I guess it shouldn't be surprising that we'd find heavier elements on the surface of literally the most massive thing in our solar system :P

11:44 PM

oh no.. I misremembered one subscript

and that caused so much confusion

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