knzhou

10 ms·

31.
by knzhou 6y ago
The people here reading GPT-3's output and dismissing it as "not really understanding anything" or "pushing symbols without conscious intent" because of minor slips in coherence have remarkably high standards for un
32.
by knzhou 6y ago
That isn't it, though. Feynman explains magnetism perfectly well in his lectures, he's just saying that he can't give a decent math-free answer in a few minutes to an interviewer with no science background. Any answer that sh
33.
by knzhou 6y ago
> Then he returned to mainland China in 1955. It's worth remembering that he did that because he was pushed out, during the Red Scare.
34.
by knzhou 6y ago
I'm glad that Sabine correctly describes Wolfram, Weinstein, and Lisi's theories as what they really are. I'm disappointed that she trots out the tired old "zero sum game" rhetoric. I work on small-scale experiments
35.
by knzhou 6y ago
While I completely agree with your general comments, I still want to emphasize how hard this ideal is to implement in practice. Yes, every subject is linked to every other subject. If I'm tutoring introductory physics, I will use exa
36.
by knzhou 6y ago
> says you need to master each step on the track before moving onto the next one. this is poisonous and borderline evil What’s wrong with it? You do need to understand calculus before classical mechanics, classical mechanics before quant
37.
by knzhou 6y ago
Special relativity is well-known for having the least prerequisites of any modern physics subject. Yes, you can explain it with just calculus and vectors. That's precisely what we already do in university courses. But the complaint tha
38.
by knzhou 6y ago
Explaining the Standard Model clearly and correctly is just really hard! I've tried, a lot. Costless simplification is impossible, because the mathematical form it's usually written in is already the simplest, clearest, and most
39.
by knzhou 6y ago
> Is "China bad" how HN and the US is going to look for the next 20 years as North America goes down the hill? As a US citizen, reading HN for a year has downgraded me from being extremely patriotic, to considering my options i
40.
by knzhou 6y ago
When I was younger I would laugh at those ridiculous "forwards from grandma" about, like, secret Satanic messages embedded in Super Mario. Every kid knew these were nonsense; we just assumed it was a consequence of that generation
41.
by knzhou 6y ago
This article reminds me of the time the city of Philadelphia tried to ban corner stores from installing bulletproof glass to protect themselves in robberies. Or the numerous education reformers trying to ban remedial classes by making all c
42.
by knzhou 6y ago
It helps shield the detectors from cosmic radiation, shields people living on the ground from radiation produced by the collider, and helps with vibrational isolation. But those are just nice bonuses. The most important reason is that there
43.
by knzhou 6y ago
> Some linear accelerator concepts could be much less expensive than very large circular colliders, but I imagine research into those areas are not funded due to the particle physics budget being mostly consumed by CERN. That's not
44.
by knzhou 6y ago
> particle physicists should focus on developing new technologies that could bring colliders back in a reasonable price range and hold off digging more tunnels People keeping saying this, but we haven't been permitted to dig a singl
45.
by knzhou 6y ago
Mostly the confidence comes from half a century of trying to find such "extra" visible mass! There's a long history of people looking for extra dust or gas or compact objects using a tremendous variety of clever techniques, a
46.
by knzhou 6y ago
Also a good idea, but the details don't work out. Specifically, early on the Fourier components of the matter density distribution grow independently. Light neutrino DM would suppress the small scale clumping too much. Making the whole
47.
by knzhou 6y ago
That's a perfectly good question, and that's exactly why for a time in the 90s they were one of the leading candidates for dark matter. Unfortunately it fell apart when we got a better understanding of structure formation, which d
48.
by knzhou 6y ago
- gravitational lensing measurements - velocities in galaxy clusters - getting the fine details of the complicated, wiggly cosmic microwave background spectrum right to extreme precision - getting the fine details of cosmological structure
49.
by knzhou 6y ago
These articles always miss the mark because they get the history backwards. Modified gravity theories were taken much more seriously in the 1970s and earlier, where the evidence for dark matter was shakier. Cosmological and astrophysical ob
50.
by knzhou 6y ago
> What is the amplitude of a single photon's wave? That doesn't have a well-defined answer, unfortunately. Suppose the electromagnetic field contains a single photon. Its electric field then necessarily exists in a superpositio
51.
by knzhou 6y ago
Nah, GP is right, if he's talking about how you can decompose states into superpositions of coherent states of the whole field . These are different from coherent states of individual modes. Specifically, a coherent state of a field i
52.
by knzhou 6y ago
I mean, that's because the language of physics is mathematics. If you ask vague questions with inherently undefined terms, you shouldn't be surprised if you get different answers! I bet chefs wouldn't agree on whether a taco
53.
by knzhou 6y ago
A beautiful book. I have all my students read it and I use its ideas every day in research.
54.
by knzhou 6y ago
I agree, and I think the overwhelmingly negative response here perfectly illustrates the post's point. The author is thoughtful and has great, but not perfect English. Because he's foreign, everybody concludes that it's a sin
55.
by knzhou 6y ago
> I've often read complains in the HN bubble that the Chinese system would be too rote. I've seen both sides. 99% of complaints you read on the internet are written by people who've never been to the country they're c
56.
by knzhou 6y ago
The MMR study took 12 years from publication to retraction. This one took 12 days.
57.
by knzhou 6y ago
Of course you can. For example, Dr. John Campbell has a popular Youtube channel where he dissects new studies. And if you just want an opposing political spin, you know Fox News and co. have Youtube channels, right? What gets taken down is
58.
by knzhou 6y ago
You could have read the paper yourself 10 days ago to find the flaws. You could have read the public discussions where scientists questioned the paper. You could have read the published "Expression of Concern" in the Lancet yester
59.
by knzhou 6y ago
The Enron scandal lasted for 10 years and was only exposed by outsiders. This paper was questioned by other scientists from the very first day, and now has been retracted by the authors themselves after barely lasting 10 days. It's not
60.
by knzhou 6y ago
That's not only a correct attitude, it's an absolutely essential one for anybody who takes science seriously. I mean, now you can understand why the WHO is always putting out statements along the lines of "no evidence yet for

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