This GSW book sounds so convincing

I can see why ST took the whole field by storm

@SillyGoose L&L 3 Quantum Mechanics

And surprisingly not Dirac's Principles of Quantum Mechanics

@lucabtz congrats

@DIRAC1930 But you're forgetting all the cranks saying it's a big failure

How do people find the number of free parameters of a matrix from a given matrix equation like $M^T L M=L$ where $L$ is some constant matrix and $M$ is a symmetric whose number of free parameters you need to find?

I asked a question here in MSE if anyone's interested.

@SillyGoose yeah i mean thats exactly what i said. theres no preferred way to reflect the environment but everything must reflect smth ab the environment. if the world obeys logic, everything in the world obeys logic. its just a tautology

@SillyGoose im of the group that doesnt care if everything is math or if theres a deeper "truth". i have yet to think of a practical question for which this matters. i am very curious and interested in things, but only to the extent that the things im exploring answer the questions i have, and i dont feel i need that "level of resolution" of knowing if math is the "truth" or not to answer any of my current questions. [...]

[...] but i am open to hearing why people are interested in this. i have just discussed it with people before and am not really persuaded to care about the philosophy of it all xD

@bolbteppa The modern incarnation of ST seems to be completely different

BAHHHHHHHHHHHHH

B A H

b a h

if you guys haven't seen yet this is one of the cutest websites ever: jellycat.com/us

awww

@bolbteppa I was wondering why it is generally a bad idea. From my perspective if I were to take another year, I would do an RA (hopefully) in the research area I applied for, which I had no actual research experience in when I applied this cycle. I don't think my letter writers would forget me, and I would have a third (hopefully) letter writer who has seen me do research (the RA PI), which I didn't have before (my third letter writer was just one of my professors).

I would also have some potentially relevant research experience from over the coming summer.

to put things in context, I applied for topological phases of matter and have research experience in biophysics and did my undergrad thesis in a quantum foundations topic (though related to decoherence which some people in top phases seem to be interested in).

i would also be open to anyone else's thoughts on the above ^

@SillyGoose bolbteppa did not explain, but it looks way worse having a random gap year. If you have a busy timeline it actually looks better, that you are desired as a researcher. If you take time off to improve yourself, it looks like nobody wants you.

They would rather hire you and train you themselves so that you can learn on the job, than have you polish yourself on your own. Generically people are very bad at learning on their own, despite all the good intentions. Being applied at research is good.

@naturallyInconsistent hm so would doing an RA in a topic relevant to the field I would apply for still look like a random gap year?

@SillyGoose no, it is ok, but you need to be able to write it as employment there.

like as in it be a full-time paid position?

most preferably

ah yes

@SillyGoose i feel like this question has just gotten twisted in a weird way and none of the advice is answering what you asked. i think if you choose to not take the offers because of whatever reasons, that is your choice, and if you are asking how to best improve chances of applying next cycle, i think that's a valid question. i dont think it matters why you dont want to accept the offers you have. that's a personal thing.

> For example, in a letter to Karl Marx of 21 March 1869 he claimed that the heat death scenario was not only scientifically nonsense but also ideologically dangerous: ‘Since, according to this theory, in the existing world, more heat must always be converted into other energy than can be obtained by converting other energy into heat, so the original hot state, out of which things have cooled, is obviously inexplicable, even contradictory, and thus presumes a God’

hello everyone

Is crank better than crackpot

turns out nlab is nothing but Marxist propaganda

(this is from Engel's book on dialectic materialism)

but then again he does say that these are from Hegel

> Moreover, anyone who is even only slightly acquainted with his Hegel will be aware that in hundreds of passages Hegel is capable of giving the most striking individual illustrations from nature and history of the dialectical laws.

Boy we have not read the same book

@user85795 Spring break? I don't get one. Not American. But I went to Portugal for reading week in February. It was awesome

19th century people were so proud of the atomic and molecular theory of chemistry

So sad that they didn't even realize they weren't even close to the bottom of physics

@Slereah It'll probably be something like this when we go beyond QFT

God I hope not

I already don't get QFT as it is

Hopefully the standard model gets completely written out of history

Tbh, there is still so many questions that need answering

e.g. why does the electron have that mass etc.

I hope it is not this en.wikipedia.org/wiki/Anthropic_principle

hey physics folks, I am looking at this paper: Thermal conductivity in one-dimensional lattices of Fermi—Pasta—Ulam type. I am confused what people mean when they write the position variable in terms of the displacement from equilibrium.

Thats how they write the Hamiltonian for a system of N particles

@Monty I don't know if this is any help tcm.phy.cam.ac.uk/~bds10/aqp/handout_phonons.pdf

thanks Dirac

in the first equation (11.1) how would you adapt that for fixed boundary coniditons ?

Sorry I don't know much about this

Say fixing the 0^th atom to be at $0$ and the $N+1^{th}$ to be at say $L$ so the chain has a fixed length $L$.

(also note that 11.1 is the Lagrangian not the Hamiltonian)

Forced to read papal notes for the history section of the GR book

papalencyclicals.net/pius12/p12exist.htm

I wonder who's the most unlikely guy who weighed in on general relativity

@Slereah How come? also what gr book

but surely drawing wisdom from different sources has its merits

as inspiration for thoughts

Mine own

And this papal bullae was important for historical development of cosmology

Especially as it relates to the soviet union

Is the book nearing completion? I'd love to take a look :O

I probably won't understand half of it though, but the history section would be fascinating to me

@NaturallyInconsistent Do you know where this entropy-temperature formula is derived from $\frac{S}{NK}=\ln\left(2\cosh\frac{1}{x}\right)-\frac{1}{x}\tanh\frac{1}{x}$

where $x = kT/\mu B$

also, im asneeppuuu dont ping

Ohh sorry!

Yes I found it actually, was problem 3.23 in schroeder

go back to sneepu

i.e. chapter 3, i.e. way too early to be doing such problems

@Obliv nowhere near :p

I wish I was better at stat mech

I have no idea how I managed to do well in my year 3 exam when I was an undergraduate

Stat mech is probably the only thing that is complete in its fundamentals

Haven't even started stat mech yet, almost there though. 1 more chapter

my only regret is not taking more chem courses since a lot of thermo overlaps with chem. Knowing about atoms & gases is pretty important for some of this material. Of course, it doesn't have to go that far

If I didn't have to take electives to fill up my schedule I would have just done physics in chronological order like classical mech, EM, QM then thermo/optics, etc

would have just taken like 1 physics course per semester and 3-4 math ones

@Obliv Why not more physics courses lol?

I feel like it's a waste of time if you only have rudimentary knowledge of a subject

It's just my preference though, that I'd rather dive deep into a subject from start to finish rather than pick at it at different levels

@SillyGoose throwing away some likely incredible offers on the theoretical hope of a better offer with a worse application is obviously a mistake, you're likely going to have 2 more years of courses before you even get near research and the direction you end up going is basically up to you to prepare for for the next 2 study years, you will likely have many people to end up working with, your background is basically irrelevant now that you're in with offers

@DIRAC1930 i think some people would disagree: foundations of quantum statistical mechanics seems to be a current and active area of research

@SillyGoose Whats bolbteppa talking about in the above. I missed what was said in the chat before

Once again I'm thinking about this question of mine and now I find elsewhere this

Does $(17)$ make any sense to you?

Damn Ising modeeeeeels

@SirCrackpot fr

That exponentiation makes no sense to me

They're saying that $$e^x+ke^{-x}\propto\exp\left[{-\frac{k}{2}\log\tanh(x)}\right]$$

Does the pressure of a fluid change the efficiency at which it can absorb heat?

The boiling point of water, for example, increases as its pressure does.

For a steam engine, we have to pressurize the water and then heat it to create high pressure steam. Why is it more efficient to do this instead of just heating it up through combustion to start with in order to pressurize it?

I wonder if there's a higher level definition of enthalpy in QFT or something

Oh good timing :D @DIRAC1930 is there?

oh nvm I guess enthalpy only makes sense in gases

I was thinking of some kind of definition where it takes into account the energy density of the vacuum