8 ms·

How to become a good theoretical physicist

95 points by apsec112 6y ago

eointierney 6y ago
Or how to become a better theoretical physicist. Generality and technical ability, proper mathematical awareness, historical understanding and appreciation of our forerunners. Mainly read the damned texts and task good teachers when confused. Go hard, go long, never give up. Seek elegance. Don't be afraid to disagree but always be rigorous. Play well with others. Ask the ancient questions and think better. I don't have a Noble prize for Physics I just study the work of those who do
mnemonicsloth 6y ago
I am working on something like this myself. I started by reading the Structure and Interpretation of Classical Mechanics, which uses Scheme to teach Hamiltonian and Lagrangian mechanics. And it's much more effective than an ordinary math/physics book. Normal math is a kind of code, except that the VM that executes it is your brain. You (or I, anyway) can only progress if you understand absolutely everything down to the last detail. Programming is much easier. If you don't understand something you can put together a little simulation to poke at the edge cases. So I finished SICM and I thought, "wouldn't it be cool if I could keep learning physics like this?" And so now I've gotten in touch with some physics postdocs (who are paid shockingly little). I pay them to learn Scheme and encode quantum mechanics, general relativity, statistical mechanics as scheme programs. I work on this about 10 hours a week. In a year or two I'll have knowledge equivalent to an ABD physics grad student, plus information that can take other people from modest beginnings to the same level. One thing this project has taught me is that students have shockingly little power in their relationships with teachers. I am a major source of income for my postdocs. Some of them may be prioritizing me over some of their other duties. And it really shows. I'm a good self-learner, but there is no substitute for having someone work really hard to anticipate all your questions. Another thing I've noticed is that everyone (except, increasingly, my postdocs) is a terrible teacher in academia. I have a friend, a fellow grad student, who is scheduled to teach her first lab in her first semester. The lab meets Tuesday. The one-hour credit-only class that will supposedly teach her how to teach meets Wednesday. On day one she'll be going in completely unprepared. And she's not atypical. I suppose that, since students have no power, few people care whether they learn well or just adequately, so people (administrators, professors) prioritize other things. The glaring exception to all this proves the rule. The one person who has done the most to make me successful in graduate school has been my advisor -- and his name will be on every paper I publish. (I like the guy a lot, but self-interest plays a role)
- gowld 6y ago
  Do you have any plans to publish those scheme programs? More generally, "theoretical physics software" seems like an area that many people are interested in The list at http://www.theophys.kth.se/afsinfo/software/official.html http://www.theophys.kth.se/afsinfo/software/official.html is tragically bereft of software that relates to Physics (except Mathematica)
  - mnemonicsloth 6y ago
    Absolutely. The goal is to make ABD status available to anyone. Students learn better with programs than with lectures. Profs have more time because they don't have to lecture. Grad school becomes a more collaborative, research-based experience. It seems like a win-win to me. The software side of it is tricky though. You often need a mental model before you can code. That's got to come by text, video, or whatever. So I have to develop something like a dynamic book with an embedded REPL. I've heard of small efforts in that direction (_why's tryruby.org was good but it's been taken down), but nothing built-out enough to support a multi-year reading project.
    - DennisP 6y ago
      I would love this. Please let us know when you have something online, even if it's just a work in progress on github.
    - sritchie 6y ago
      Amazing. I’m actually building this exact thing now at https://GitHub.com/sritchie/sicm https://GitHub.com/sritchie/sicm for that book, and working on a port of https://github.com/littleredcomputer/sicmutils https://github.com/littleredcomputer/sicmutils to Clojurescript to power this exact style of interactive textbook in the browser. I’d love to talk more if you’re interested in teaming up, or talking about any of this in more detail.
    - tobmlt 6y ago
      This sounds great. One hopes that in the years to come, all learning takes on such a multi-faceted structure. I only wish there was a linear "wall" of learning, from baby arithmetic to algebraic cohomology, string theory, etc., with a clear(ish) path* of precedence for when you get stuck. (*generalized path, I suppose) Maybe give latex a symbolic math system while we are at it, so that it may check our notes as we type them. ;)
gpsx 6y ago
Gerard 't Hooft knows a thing or two about being a GOOD theoretical physicist. But I do have one general complaint about what he is saying. It is apparently common for people, especially ex-physicists like myself, to think they have figured it out (whatever "it" is). In reality, they just forgot (or never knew) enough to realize how bad their idea is. He pretty much agrees with this and his solution is for people to learn it all. In _general_ I don't think it's fair to say you have to be an expert to contribute. We wouldn't make any progress if nobody was allowed to make a suggestion unless they were an expert. This would pretty much silence me (in things not related physics, such as software, or if I was so inclined, in physics too). Now, I am being a little unfair. I think it is great what he is doing. AND, if anyone does think they have solved the secrets of the universe, don't take it to one of the top physicists in the world before checking it out a little more humbly. But in any oher case, just throw caution to the wind and don't worry if you don't know everything.
- mnemonicsloth 6y ago
  He pretty much agrees with this and his solution is for people to learn it all. I thought 't Hooft was saying you have to learn all of this stuff. But it sounds like you're saying you can do good work in physics without some of this information. Is that true? What can you dispense with?
  - gpsx 6y ago
    No. I wasn't trying to say that. He is right that there is a lot to know to make any contribution to physics. I was trying to make a more general comment that people shouldn't be afraid to try something even if they don't know all the background. Make mistakes and learn as you go. That applies more to "easy" things like software.
- tobmlt 6y ago
  I had a professor who was fond of saying "you have to jump in and do it" ("it" being whatever calculation, or problem, or whatever) If you are timid and stay on the sidelines, you will never do anything. Of course in physics there is the small further problem where you are up against the smartest people who have ever lived, ...sans the math folk... and double points if you have been jailed in France, doing math during a war, or similar. eh... Really though, can't we all contribute if we work hard enough?
mrwnmonm 6y ago
This was my dream :( Anyway, I like to mention the book Deep Work, I think it is essential for any science student in our age.
grendelt 6y ago
> "...in theory." Amirite? Guys? Hello? Guy? Is this thing on?
jjdredd 6y ago
I think the author is missing a couple of important points: 1) How would one approach this task having a day job? 2) How do you compensate for not having a chance to work in a suitable environment doing good research? 2a)Knowing and understanding everything that has been done in the past doesn't by itself make you a researcher. This (being a scientist) must be taught by actual theoretical physicists. There are many supervisors, but very few that can teach you to do research. 2b) Serious and worthwhile research is seldom done by one person. You need to collaborate or at least communicate with other scientists in the field (and sometimes even out of the field). You have to be in the right environment. Just reading arxiv won't quite cut it.
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 it doesn't reflect how he actually learned physics himself, nor how anybody ever has, really. It's been "under construction" (i.e. completely abandoned) for two decades. Half the links are broken, and the ones that aren't tend to be whatever the top Google hit was in the 90s, not what's pedagogically best. If you're serious about learning physics, there are many much better roadmaps, like Susan Fowler's list (https://www.susanjfowler.com/blog/2016/8/13/so-you-want-to-learn-physics https://www.susanjfowler.com/blog/2016/8/13/so-you-want-to-l...).
- oh_sigh 6y ago
  Has Susan Fowler proved herself to be a good theoretical physicst? How does one determine that her roadmap is good but OPs is bad?
  - 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 lecture notes, and wild fluctuations in sophistication. The ordering puts graduate-level stuff before its sophomore-level prerequisites. My statement would only be controversial if you believed that arbitrary adversity in learning was necessary to be a good physicist -- and for my own sake I hope that isn't the case!
    - scottlocklin 6y ago
      Yeah, well, t'Hooft's is harder to learn because it's actually a serious curriculum which is worth knowing rather than training wheels from someone who never did anything serious in physics. Title is how to be a good theoretical physicist; not "what someone might study as an undergraduate."
      - 6y ago
mhh__ 6y ago
It's also worth adding that these days libgen has almost everything wink wink.
pontus 6y ago
Oh man does this bring me back! I used to view this list as such an aspirational goal. Honestly though, if you want to become good theoretical physicist you pretty much need to go to grad school.
wintercarver 6y ago
I studied physics as an undergrad and then went on to get a PhD from UW (Seattle), which has required courses for physics education that all graduate students must take. With ~10 years of physics study/practice/teaching, I think the one meta lesson I've carried with me is it's not about which book or which method, but rather the marathon process of ongoing exploration, which is often fueled by genuine interest and joy in exploring the subject. Exploration here applies to the subject itself in spirit, but in reality means exploring the resources to gather perspective and understanding. The above probably sounds obvious (sorry!), but a lot of learning recommendation seems to focus on "the best" resource, which in my older years strikes me as kind of odd. In the grander scheme of studying something in earnest, time spent with any one book will not be the determiner of success. That's not to say there are no great books or resources, but rather if something is hard or not making sense you should try to approach the topic from another angle: read the chapter on the same topic from another text, or a few others, find some alternative lectures online, etc -- these days the resource list is near limitless... So, start somewhere, don't worry too much about how you start, and keep going! A lot of the above opinion was motivated by a kind of serendipitous conversation I had with a physics professor. I returned to that convo often enough that I finally decided to write it down last year. Pardon the self plug, but intent was to help share a learning perspective: https://medium.com/@kevinconnolly/effort-neglect-and-the-second-textbook-434a3400be2f https://medium.com/@kevinconnolly/effort-neglect-and-the-sec...
- mnky9800n 6y ago
  You are the person speaking truth in this thread.
  - wintercarver 6y ago
    Thank you for the compliment, glad to try and contribute a sliver of truth (researcher to the core lol).
- kinleyd 6y ago
  'The Second Textbook' is a nice perspective which resonates with me. In my experience I've found the need for as many textbooks as I can get my paws on - each book usually handles one or other topic better than others, or gives me that extra angle that helps my understanding.
abhayhegde 6y ago
This list is barely updated. New texts and standards have emerged, and gives no insight as to how to develop the analytical skills. Just a list of books won't do.

95 points by apsec112 6y ago

Or how to become a better theoretical physicist. Generality and technical ability, proper mathematical awareness, historical understanding and appreciation of our forerunners. Mainly read the damned texts and task good teachers when confused. Go hard, go long, never give up. Seek elegance. Don't be afraid to disagree but always be rigorous. Play well with others. Ask the ancient questions and think better. I don't have a Noble prize for Physics I just study the work of those who do

mnemonicsloth 6y ago

I am working on something like this myself. I started by reading the Structure and Interpretation of Classical Mechanics, which uses Scheme to teach Hamiltonian and Lagrangian mechanics. And it's much more effective than an ordinary math/physics book. Normal math is a kind of code, except that the VM that executes it is your brain. You (or I, anyway) can only progress if you understand absolutely everything down to the last detail. Programming is much easier. If you don't understand something you can put together a little simulation to poke at the edge cases. So I finished SICM and I thought, "wouldn't it be cool if I could keep learning physics like this?" And so now I've gotten in touch with some physics postdocs (who are paid shockingly little). I pay them to learn Scheme and encode quantum mechanics, general relativity, statistical mechanics as scheme programs. I work on this about 10 hours a week. In a year or two I'll have knowledge equivalent to an ABD physics grad student, plus information that can take other people from modest beginnings to the same level. One thing this project has taught me is that students have shockingly little power in their relationships with teachers. I am a major source of income for my postdocs. Some of them may be prioritizing me over some of their other duties. And it really shows. I'm a good self-learner, but there is no substitute for having someone work really hard to anticipate all your questions. Another thing I've noticed is that everyone (except, increasingly, my postdocs) is a terrible teacher in academia. I have a friend, a fellow grad student, who is scheduled to teach her first lab in her first semester. The lab meets Tuesday. The one-hour credit-only class that will supposedly teach her how to teach meets Wednesday. On day one she'll be going in completely unprepared. And she's not atypical. I suppose that, since students have no power, few people care whether they learn well or just adequately, so people (administrators, professors) prioritize other things. The glaring exception to all this proves the rule. The one person who has done the most to make me successful in graduate school has been my advisor -- and his name will be on every paper I publish. (I like the guy a lot, but self-interest plays a role)

gowld 6y ago
Do you have any plans to publish those scheme programs? More generally, "theoretical physics software" seems like an area that many people are interested in The list at http://www.theophys.kth.se/afsinfo/software/official.html http://www.theophys.kth.se/afsinfo/software/official.html is tragically bereft of software that relates to Physics (except Mathematica)
- mnemonicsloth 6y ago
  Absolutely. The goal is to make ABD status available to anyone. Students learn better with programs than with lectures. Profs have more time because they don't have to lecture. Grad school becomes a more collaborative, research-based experience. It seems like a win-win to me. The software side of it is tricky though. You often need a mental model before you can code. That's got to come by text, video, or whatever. So I have to develop something like a dynamic book with an embedded REPL. I've heard of small efforts in that direction (_why's tryruby.org was good but it's been taken down), but nothing built-out enough to support a multi-year reading project.
  - DennisP 6y ago
    I would love this. Please let us know when you have something online, even if it's just a work in progress on github.
  - sritchie 6y ago
    Amazing. I’m actually building this exact thing now at https://GitHub.com/sritchie/sicm https://GitHub.com/sritchie/sicm for that book, and working on a port of https://github.com/littleredcomputer/sicmutils https://github.com/littleredcomputer/sicmutils to Clojurescript to power this exact style of interactive textbook in the browser. I’d love to talk more if you’re interested in teaming up, or talking about any of this in more detail.
  - tobmlt 6y ago
    This sounds great. One hopes that in the years to come, all learning takes on such a multi-faceted structure. I only wish there was a linear "wall" of learning, from baby arithmetic to algebraic cohomology, string theory, etc., with a clear(ish) path* of precedence for when you get stuck. (*generalized path, I suppose) Maybe give latex a symbolic math system while we are at it, so that it may check our notes as we type them. ;)

gpsx 6y ago

Gerard 't Hooft knows a thing or two about being a GOOD theoretical physicist. But I do have one general complaint about what he is saying. It is apparently common for people, especially ex-physicists like myself, to think they have figured it out (whatever "it" is). In reality, they just forgot (or never knew) enough to realize how bad their idea is. He pretty much agrees with this and his solution is for people to learn it all. In _general_ I don't think it's fair to say you have to be an expert to contribute. We wouldn't make any progress if nobody was allowed to make a suggestion unless they were an expert. This would pretty much silence me (in things not related physics, such as software, or if I was so inclined, in physics too). Now, I am being a little unfair. I think it is great what he is doing. AND, if anyone does think they have solved the secrets of the universe, don't take it to one of the top physicists in the world before checking it out a little more humbly. But in any oher case, just throw caution to the wind and don't worry if you don't know everything.

mnemonicsloth 6y ago
He pretty much agrees with this and his solution is for people to learn it all. I thought 't Hooft was saying you have to learn all of this stuff. But it sounds like you're saying you can do good work in physics without some of this information. Is that true? What can you dispense with?
- gpsx 6y ago
  No. I wasn't trying to say that. He is right that there is a lot to know to make any contribution to physics. I was trying to make a more general comment that people shouldn't be afraid to try something even if they don't know all the background. Make mistakes and learn as you go. That applies more to "easy" things like software.
tobmlt 6y ago
I had a professor who was fond of saying "you have to jump in and do it" ("it" being whatever calculation, or problem, or whatever) If you are timid and stay on the sidelines, you will never do anything. Of course in physics there is the small further problem where you are up against the smartest people who have ever lived, ...sans the math folk... and double points if you have been jailed in France, doing math during a war, or similar. eh... Really though, can't we all contribute if we work hard enough?

mrwnmonm 6y ago

This was my dream :( Anyway, I like to mention the book Deep Work, I think it is essential for any science student in our age.

grendelt 6y ago

> "...in theory." Amirite? Guys? Hello? Guy? Is this thing on?

jjdredd 6y ago

I think the author is missing a couple of important points: 1) How would one approach this task having a day job? 2) How do you compensate for not having a chance to work in a suitable environment doing good research? 2a)Knowing and understanding everything that has been done in the past doesn't by itself make you a researcher. This (being a scientist) must be taught by actual theoretical physicists. There are many supervisors, but very few that can teach you to do research. 2b) Serious and worthwhile research is seldom done by one person. You need to collaborate or at least communicate with other scientists in the field (and sometimes even out of the field). You have to be in the right environment. Just reading arxiv won't quite cut it.

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 it doesn't reflect how he actually learned physics himself, nor how anybody ever has, really. It's been "under construction" (i.e. completely abandoned) for two decades. Half the links are broken, and the ones that aren't tend to be whatever the top Google hit was in the 90s, not what's pedagogically best. If you're serious about learning physics, there are many much better roadmaps, like Susan Fowler's list (https://www.susanjfowler.com/blog/2016/8/13/so-you-want-to-learn-physics https://www.susanjfowler.com/blog/2016/8/13/so-you-want-to-l...).

oh_sigh 6y ago
Has Susan Fowler proved herself to be a good theoretical physicst? How does one determine that her roadmap is good but OPs is bad?
- 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 lecture notes, and wild fluctuations in sophistication. The ordering puts graduate-level stuff before its sophomore-level prerequisites. My statement would only be controversial if you believed that arbitrary adversity in learning was necessary to be a good physicist -- and for my own sake I hope that isn't the case!
  - scottlocklin 6y ago
    Yeah, well, t'Hooft's is harder to learn because it's actually a serious curriculum which is worth knowing rather than training wheels from someone who never did anything serious in physics. Title is how to be a good theoretical physicist; not "what someone might study as an undergraduate."
    - 6y ago

mhh__ 6y ago

It's also worth adding that these days libgen has almost everything wink wink.

pontus 6y ago

Oh man does this bring me back! I used to view this list as such an aspirational goal. Honestly though, if you want to become good theoretical physicist you pretty much need to go to grad school.

wintercarver 6y ago

I studied physics as an undergrad and then went on to get a PhD from UW (Seattle), which has required courses for physics education that all graduate students must take. With ~10 years of physics study/practice/teaching, I think the one meta lesson I've carried with me is it's not about which book or which method, but rather the marathon process of ongoing exploration, which is often fueled by genuine interest and joy in exploring the subject. Exploration here applies to the subject itself in spirit, but in reality means exploring the resources to gather perspective and understanding. The above probably sounds obvious (sorry!), but a lot of learning recommendation seems to focus on "the best" resource, which in my older years strikes me as kind of odd. In the grander scheme of studying something in earnest, time spent with any one book will not be the determiner of success. That's not to say there are no great books or resources, but rather if something is hard or not making sense you should try to approach the topic from another angle: read the chapter on the same topic from another text, or a few others, find some alternative lectures online, etc -- these days the resource list is near limitless... So, start somewhere, don't worry too much about how you start, and keep going! A lot of the above opinion was motivated by a kind of serendipitous conversation I had with a physics professor. I returned to that convo often enough that I finally decided to write it down last year. Pardon the self plug, but intent was to help share a learning perspective: https://medium.com/@kevinconnolly/effort-neglect-and-the-second-textbook-434a3400be2f https://medium.com/@kevinconnolly/effort-neglect-and-the-sec...

mnky9800n 6y ago
You are the person speaking truth in this thread.
- wintercarver 6y ago
  Thank you for the compliment, glad to try and contribute a sliver of truth (researcher to the core lol).
kinleyd 6y ago
'The Second Textbook' is a nice perspective which resonates with me. In my experience I've found the need for as many textbooks as I can get my paws on - each book usually handles one or other topic better than others, or gives me that extra angle that helps my understanding.

abhayhegde 6y ago

This list is barely updated. New texts and standards have emerged, and gives no insight as to how to develop the analytical skills. Just a list of books won't do.