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

The number of basic research jobs in physics is a pretty fixed supply, since it's determined largely by public funding, and there are always many more applicants than jobs. Therefore, any trends you've noticed about physicists leaving the field for other jobs is much more reflective of the number of students entering the field (always rising) who eventually must leave, and the extent to which they publicly discuss their experiences. If anything, hearing about more people leaving physics would be a positive indicator for the desirability of the field, since it just means more people tried and failed to obtain a slot. (As it happens, I think fundamental physicists research is a pretty diseased field, but a shortfall in researchers due to PhDs being drawn away to greener pastures is not a symptom.)

Note that applied physics is different, since there is an actual market in researchers for industrial R&D; a shortfall in jobs really could reflect a failing field. My vague impression is rather that applied physics is booming, but know very little about that.

And just to be clear on the numbers: If, over a career, every research professor mentors N grad students, and the number of research professor jobs grows slowly (as it has since the explosive growth in prof jobs that peaked in the '60s has waned), then the chance of any PhD becoming a professor must be about 1/N. If you look at the numbers, that chance is a few percent, which agrees with the typical professor advising ~20 students over a career. That means ~95% of PhD are going to be leaving to do something else.

Anyways, for me personally: I have a PhD in quantum information and am currently searching for a mathematical definition of branches in a many-body wavefunction. This would potentially lead to large computational speed-ups in numerical simulations of out-of-equilibrium systems. I'm in my 7th year of postdoc-ing which...is not ideal.

Yeah. I keep kicking myself for not taking the Wall Street guys who called me more seriously. That would be one important message I'd like to send backward in time.

I remember some of the Physics departments I knew well commenting that they were getting 250+ applications for each open tenure track position (early/mid 90s). It skyrocketed to 1000+ at one point for a few places.

Based on some back of the envelope math, and a realization that a fresh Ph.D. with ~6 publications (2 PRL, 4 others) would not be a good competitor to a senior FSU physicist with 50+ publications to their name, a solid reputation, and an interest in moving out of the FSU quickly.

I determined that market forces had flooded the supply side of physics with, well, extremely good candidates for the same positions I was applying for. And my ability to compete with them was low based upon the main components that hiring committees cared about.

So I looked elsewhere. 20+ years later, I've made a good career working in computing, but I really do miss physics and research in general.

    First of all, you definitely don't want any chance of incorrect recognition of handwriting coming from a nuclear weapons plant.

So if we take some of the thought processes behind Stat Mech (or S&M as we used to call it in grad school), and you kinda squint your eyes hard to blur the less robust discussions you read about, you get the sense that ML is more about the "thermodynamics of information" than anything else.

I find this intriguing and definitely want to spend more time on this stuff.