Ask HN: Physicists of HN, what are you working on these days?

Re:Ask HN: Physicists of HN, what are you working on these d... by PaulHoule on Wednesday March 27, 2019 @09:05AM (#19500412)

When I got my PhD (1999) the American Physical Society said that you had a 2% chance of getting a permanent job in the field with a PhD. At that point you are not being judged on your merits but on your connections, ability to navigate politics, etc. (The job is way too valuable compared to the value you can give to it.)

I saw a postdoc who is now rather well known struggling with anxiety over his career even though he had written half a book and done a lot of great work. When we were both at Cornell I'd come to the conclusion that many papers involving "power law" distributions were bogus because nobody knew how to test for them with any rigor. It was years later, after he had tenure, that he published something about it in a statistics journal.

Seeing that made me run for the exit after my first year as a postdoc.

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Re:Ask HN: Physicists of HN, what are you working on these d... by mjburgess on Wednesday March 27, 2019 @09:12AM (#19500470)

> I'd come to the conclusion that many papers involving "power law" distributions were bogus

> after he had tenure, that he published something about it in a statistics journal

If I'm reading you right, you're saying he struggled for awhile doing bogus things only to question those things outside the relevant field?

(Also, can you say more about power law papers..?)

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Re:Ask HN: Physicists of HN, what are you working on these d... by PaulHoule on Wednesday March 27, 2019 @11:45AM (#19502068)

I wrote one (experimental) bogus paper. He wrote quite a few papers, I'm not sure if any of them used the experimental non-technique that was common at the time.

So there is a theory based on the renormalization group that can explain many (but not all) "fractal" phenomena that are observed.

I was part of the false paradigm of "bin up a probability distribution", "plot it up on log-log paper", and "draw a straight line."

Sometimes when you do that you will get an answer that has something to do with reality but it is not a valid answer to the problems of: "is a power law distribution a good model of this phenomenon", "what is a good estimate of the exponent", "are these two power law charts drawn from the same distribution" not to mention how to handle the problems that turn up at the highly frequent and highly rare ends of the distribution.

The root cause is this attitude

http://thinkexist.com/quotation/if_your_experiment_needs_sta...

and an academic system where power is too concentrated, where people who write review articles do the most good but get the least career advancement, etc.

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Re:Ask HN: Physicists of HN, what are you working on these d... by fearhugs on Wednesday March 27, 2019 @10:07AM (#19500890)

I read the comment as saying that the postdoc kept his reservations about power law distributions to himself until after he had tenure, so as to not upset the applecart I suppose... ?

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Re:Ask HN: Physicists of HN, what are you working on these d... by joycian on Wednesday March 27, 2019 @09:19AM (#19500524)

I read the comment as implying that the colleague had published a paper on power law distributions in order to publish (pressure) while the poster knew that the colleague did not believe in the subject.

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Re:Ask HN: Physicists of HN, what are you working on these d... by madhadron on Wednesday March 27, 2019 @12:10PM (#19502389)

There was a similar issue with power laws in biology, mostly driven by a guy named Barabasi. I don't think any of his results have held up when someone did the math right, but he's gone so far as to try to politically pressure people to keep quiet about it because they were hurting his career.

I've been out for a few years, so I don't know what the current state of affairs is.

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Re:Ask HN: Physicists of HN, what are you working on these d... by scottishcow on Thursday March 28, 2019 @12:32AM (#19509273)

Surprised to hear this about Barabasi, I'm no physicist but enjoyed reading his books on network science as a layperson.

Is there any published criticism against his work? His papers get cited everywhere, I know citations are more metric of popularity than scientific quality but I find it puzzling that his work continues to get attention if the results don't hold up.

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Re:Ask HN: Physicists of HN, what are you working on these d... by madhadron on Thursday March 28, 2019 @03:00PM (#19515391)

You could start with Pachter's sendup (https://liorpachter.wordpress.com/2014/02/10/the-network-non...), and the Wikipedia article on Barabasi has a short section on criticisms. I read his work, figured out it was nonsense, and put him on the list of authors whose papers I automatically threw in the garbage. Kim Lewis is another one of those.

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