I think the lockdown gave them enough data to run a meta-analysis on the effectiveness of the flipped classroom idea.

The same kind of promises Growth Mindset and Brain Plasticity was making.

@SillyGoose .... how are you hoping to understand all that deep QFT headaches (and Hamiltonian) without first playing with simple QM, CFT, etc? Like, ACM said H atom, but actually you should also do basic molecules LCAO.

@SillyGoose we are doing peer instruction here in this chat...

Most instructional ideas are actually workable. The problem is that people who dont understand it but are forced to implement them, tend to do a horrendous job at it, rendering any brilliant idea into a pixellated mess.

@naturallyInconsistent well this setting from my perspective is more like being able to ask people who are quite more knowledgable than i am in physics. in that sense I don't see myself as a peer since I consider peer to be used to describe two individuals at something like the same level of academic knowledge

@naturallyInconsistent well i have done all the canonical intro quantum systems and solving but def not basic molecules. no field theory either for sure

@SillyGoose fair, but the idea isnt nonsense. the essence is that almost everybody has the same few misconceptions; if you get paired with one that is the same as yours, then tough, but it is possible for 2 wrongs to reason out to the correct view

@naturallyInconsistent I can see that it could work. and maybe my institution is just biased in such a way that made me dislike such types of instruction. in my experience at my institution, there are a disproportional number of students who lack (or perhaps do not care so much about the content of the course, so as to give off an impression of lacking) basic knowledge to do with the course. for example, pre-reqs and content already covered.

To a certain degree this lacking is expected (no one can learn and remember everything), but not to the degree that I have seen it...

i think most institutions would have this problem; we should not expect students to be that proactive, it isnt realistic. instead, peer instruction should be used sparingly, in those somewhat rare but insightful situations where a simple to understand question clashes with intuition to give an unexpected answer

only the top unis can enjoy a student body that would be on top of instructions; and even they would have students interested in gaming than lectures, or be there just for credits and just used money to get in, etc

@ACuriousMind Are you hinting at the fact that it could be someone else posing to be Kerr and posting stuff in his name?!

@Sanjana No, he's pointing out that sometimes old scientists & mathematicians start making bogus claims. Eg, Michael Atiyah. He was a prolific influential mathematician who said some dumb stuff towards the end of his life.

> In October 2016, he claimed[119] a short proof of the non-existence of complex structures on the 6-sphere. His proof, like many predecessors, is considered flawed by the mathematical community, even after the proof was rewritten in a revised form.

> At the 2018 Heidelberg Laureate Forum, he claimed to have solved the Riemann hypothesis, Hilbert's eighth problem, by contradiction using the fine-structure constant. Again, the proof did not hold up and the hypothesis remains one of the six unsolved Millennium Prize Problems in mathematics, as of 2023.

($\lvert m \rangle$ is a $\sigma_z$ eigenvector, so $m=\pm1$). Isn't this identity false? It should be $$\langle m \lvert \exp[gJa\hat{\sigma}_x]\lvert m'\rangle=\frac{1}{2}(e^{Jga}+m'me^{-Jga})$$

Playing with exponentials won't give their result $$\frac{1}{2}[\cosh (2Jga)\exp(-m'm\log \tanh(Jga)/2)]$$

diathermal refers to a boundary across which the Temp gradient is zero even in the presence of heat transfer?

wouldn't the net heat transfer be zero if the Temp difference is zero?

Can someone explain Why is work done in a reversible PdV, is this work done by the environment or work done by the system ( I am using heat engine sign convention )

work done is system is considered positive in my convention

@Mr.Feynman are you playing with spin 1? The usual identities do not seem to work

@Shashaank infinitesimally slow transfer, not zero transfer

@Shashaank The only sensible convention is the physics convention, namely that the energy of a gas in a piston is $E=TS-pV$. The other convention is convenient for engineering, but it is ultimately confusing. The only thing we actually account completely for, is the gas.

Trying to read some modern black hole stuff to give a better answer to that Kerr paper

Worst thing

@naturallyInconsistent no, spin $1/2$. The notation is $\pm1 instead of \pm 1/2$ because we deal with Pauli matrices directly

I'm learning stuff about the quantum Ising chain

Or should I say Ising pain?

I'd point out that both of you are wrong. $$\left<m|\text{exp}[k\hat\sigma_x]|m^\prime\right>=\left<m|\cosh[k]+\hat\sigma_x\sinh[k]|m^\prime\right>$$ which means that it equals the single cosh if $m=m^\prime$ and equals the single growing exponential if they are different, nothing else. Your solution gets the cosh but does not get the growing exponential, whereas the quoted solution gets neither.

This was also why I wanted to check if it were spin-1. If it were, then we cannot use the exponential -> cosh and sinh grouping, because then $\hat\sigma_x^2\neq\pm\mathbb I$

hi

@naturallyInconsistent if they are different you get a $\sinh$

The identity piece with the hyperbolic cosine dies because $\langle m\lvert \cosh(k)\mathbb{I}\lvert m'\rangle=\cosh(k)\langle m\lvert m'\rangle=0$

Oh yeah, you are correct. Then we agree

Anyway, I couldnt get the $\frac12\cosh2k\left[\sqrt{\tanh k}\right]^{\pm1}$ to agree with us

Neither did I. I'll work on this tomorrow (because the mapping to a classical system depends crucially on this passage)

Bye

@Slereah don't bother...

I am being told that Kerr is being an old man and ignoring modern treatment of the Kerr metric

the only thing to note is that "singularity theorem" is just a misnomer

@Slereah Obviously they know more about the Kerr metric than Kerr