knzhou

11 ms·

1.
by knzhou 4y ago
The Physical Review is a gigantic set of journals, and like anything of its size, many of its published results are wrong. At this very moment I'm writing a rebuttal to a PRD paper that arrived at nonsensical conclusions due to some ba
2.
by knzhou 4y ago
Indeed, the author's 2000-page online textbook, heavily promoted on the internet, is a classic trap for unwary students. It looks alright at first: volume I is light on math, but full of neat examples. But it's full of intuitively
3.
by knzhou 5y ago
This is a new proposal, fresh on the arXiv today, from a group of U.S. particle physicists. The introduction is very readable and lays out the mission clearly: > We can now confidently claim that the “Standard Model” of particle physics
4.
by knzhou 5y ago
One should keep in mind that most dark matter "alternatives", including this one, actually include dark matter. It says so right on the 2nd page of their paper: > Consider requirement (iii), that is, successful cosmology. In
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by knzhou 5y ago
> What happened to the recent work showing that galactic rotation curves are consistent with ordinary GR? Last I read, cosmologists were choosing to ignore it. Gravitomagnetism is a well-understood and experimentally measured effect. It
6.
by knzhou 5y ago
This is why I left this site. Endless smug engineers explaining condescendingly to physicists why they’re stupid sheep, without knowing the first thing about anything. Intellectual curiosity, my ass. Do you have a reply to my concrete criti
7.
by knzhou 5y ago
The same criticism applies for any other crappy paper HN likes. Whenever I check this site, half the time the front page has something even worse. Just assume everything you see here is wrong.
8.
by knzhou 5y ago
Gravitomagnetism is a well-understood and experimentally measured effect. It is also a very small effect, of the order v^2 / c^2 where v is the speed of the sources. In the galaxy, stars move with v/c ~ 1/1000, which means th
9.
by knzhou 6y ago
I'm glad we agree that development and opportunity are good things. The average per capita income in China is lower than countries like Costa Rica or Venezuela. It's less than half of what a minimum wage worker gets in the US. Eve
10.
by knzhou 6y ago
When did I make that argument?
11.
by knzhou 6y ago
It was not a hard thing to infer. There is a very particular kind of deep ignorance one needs to write a comment like OP's.
12.
by knzhou 6y ago
Yes, you didn't, but you weren't really looking, were you?
13.
by knzhou 6y ago
All of these examples are pieces of entertainment being pulled because they offend Chinese sensibilities. Here's the thing: pieces of entertainment are also pulled if they offend American sensibilities. In fact, American sensibilities
14.
by knzhou 6y ago
> OP described living in a China-centric world, not one of equals. Yes, but there's no evidence to suggest this will be the case. The average yearly income in China is not even half what a minimum wage worker gets in the US! And yet
15.
by knzhou 6y ago
> The original commenter professed a fear of what that would look like for outsiders in a China-centric world. Yes, and for the third time now: my point is that the absolute worst-case scenario for the original commenter is still miles b
16.
by knzhou 6y ago
Do you really think agitating for World War III was productive to start with? I pointed out rationally and straightforwardly where such extreme opinions come form.
17.
by knzhou 6y ago
The "discrimination" they fear is no longer automatically being worshipped the second they step foot in a non-Western country, for being the richest guy in every room. In other words, what they actually fear is dropping from 99th
18.
by knzhou 6y ago
Well, I've read almost all the books she lists and I've been a quantum field theory practitioner for years, and I can at least attest the list is good. People actually learn from these books. I think your comment also directly ill
19.
by knzhou 6y ago
This is a great point. Out of all the ones I've looked into, I think MIT has by far the most complete public curriculum (because of MIT OCW), but Cambridge and Oxford are not far behind, with excellent lecture notes and problem sets.
20.
by knzhou 6y ago
I personally know the vast majority of the material in both roadmaps, so I know that 't Hooft's is far harder to learn from. Anybody can check this for themselves. There's plenty of broken links, extremely rough drafts of lec
21.
by knzhou 6y ago
This is cool as always, but in case anybody is seriously contemplating using it: this list is infamous for its complete uselessness for anybody actually trying to learn. It's mostly recommended because of 't Hooft's name, but
22.
by knzhou 6y ago
> Sort of the difference between a wall that keeps you in versus a wall that keeps unwelcome people out. And how do you think the Chinese state describes the Chinese firewall?
23.
by knzhou 6y ago
Curious about the downvotes. Do people believe that this curtailment of freedom can't happen in America? I know people already rushing to prepare for it. Or perhaps they believe that it will happen, but that it's a good thing? Or
24.
by knzhou 6y ago
Time to get a VPN if you want to communicate across the Great Firewall of America.
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by knzhou 6y ago
Actually, in the context of astrophysics, that exact objection has been employed many times. For example, the most famous argument against heliocentrism was that it would require the stars to be ridiculously far away and ridiculously big to
26.
by knzhou 6y ago
> To me, again as an outside observer, it feels so counter-intuitive to _invent_ a new type of matter you can't observe than to just say that your calculation is close but not right and to start over. Is it not a crutch? Physicist h
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by knzhou 6y ago
This is one of those completely false things that people only believe is true by repetition. Go back and actually read the full set of WHO statements in mid-January. They have a bunch of statements saying that nations should get prepared, o
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by knzhou 6y ago
> The modeling from IMHE shows that in March the number of daily new infections were above 250K whereas today are about 120K. Yeah, but the IHME model is also extremely bad. It consists almost entirely of fitting a Gaussian to the number
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by knzhou 6y ago
Again, just substitute the words. But the point of Olympic medals is to assess skill. If the available pool of talented athletes is larger than the number of gold medals, then there is a need for more gold medals.
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by knzhou 6y ago
No, because school prestige is a positional good. This is like saying you can address the shortage of Olympic gold medals by just manufacturing tons of them.

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