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How to Become a Good Theoretical Physicist

157 points by seycombi 9y ago

keldaris 9y ago
It's a good comprehensive list, but considerably biased by the author's research interests. There are lots of good theoretical physicists that don't know much about the specifics of string theory and haven't seen general relativity since the relevant graduate course, it just depends on the field you decide to specialize in. On the math side, aside from a few things very specific to string theory, most of it is useful throughout modern theoretical physics, and it certainly helps to have at least a passing familiarity with all of the subjects listed for general erudition. The list could also be expanded with lots of things on the computational side that aren't immediately useful to string theorists but are used in many other fields. Disclaimer: just a theoretical physics postdoc, YMMV.
komali2 9y ago
>Unfortunately, I still have to recommend to buy text books as well Why? EDIT: Why buy textbooks, rather than read online resources and online textbooks?
- archgoon 9y ago
  There is a huge amount of information that has been written down. Different authors have different explanations and takes on things, and will emphasize different aspects of a topic in their presentation. Look at the recommended texts section: http://www.staff.science.uu.nl/~gadda001/goodtheorist/texts&resources.html http://www.staff.science.uu.nl/~gadda001/goodtheorist/texts&... He doesn't just cite one text on Classical Mechanics, he cites 5, and in his section on internet resources http://www.staff.science.uu.nl/~gadda001/goodtheorist/classmech.html http://www.staff.science.uu.nl/~gadda001/goodtheorist/classm... He cites 3 more courses. There is a lot of depth in any of these topics, and any given presentation will be a single path, of many, through the topic. Different perspectives are valuable, as they also help clarify the core of the topic, and allow you to find your own perspective. We are fortunate that there are people who have invested the effort to put some of these resources online, but not everything is currently on the internet. One day perhaps. Also, some of the internet resources that he links to are now gone, and may or may not have been archived. Textbooks that are cited are almost certainly guaranteed to be available through some library. Given that he's also advocating that serious students attend University, proposing books to read that students can access through ILL seems reasonable.
komali2 9y ago
http://www.staff.science.uu.nl/~gadda001/goodtheorist/primarymathematics.html http://www.staff.science.uu.nl/~gadda001/goodtheorist/primar... I wonder, for someone like me that got a pretty terrible math education, how these free courses stack up against just using khan academy or similar.
- kronos29296 9y ago
  Some of the basics - Khan academy is easy to understand and gives a good foundation. Don't even try to compare the advanced stuff. Just don't. Takes a lot of work and takes years. Even grad students run away from some of the stuff.
  - signa11 9y ago
    indeed. here is an article that was posted here not so long ago : http://m.nautil.us/issue/43/heroes/what-does-any-of-this-have-to-do-with-physics http://m.nautil.us/issue/43/heroes/what-does-any-of-this-hav...
  - pvg 9y ago
    The stuff linked on the page is stuff you'll learn as an undergrad or before.
    - Retric 9y ago
      'Learn' can be fuzzy. IMO, most undergrads taking an undergrad DifEq course will have little understanding of what they are actually doing and just treat it as symbol manipulation. I have seen people encounter the same problem with calculus, matrices, or even simple algebra. And you can keep pushing, but at some point if you want to progress you need to revisit older topics and hopefully gain new understanding. It's like revisiting multiplication and division in binary and suddenly understanding why a similar process in base 10 works. PS: Pure symbol manipulation is still powerful, but intuition takes a little more.
      - pvg 9y ago
kazanz 9y ago
I would love to see similiar sites set up in other disciplines of various knowledge bodies: Politcal science, economics, philosophy, computer science, etc
- kiliantics 9y ago
  Yeah, an Econ one is badly needed for all the libertarian economics experts
52-6F-62 9y ago
This is exactly like what I've been looking for -- a bit of a roadmap leading up to [hopefully] returning to school. I've started, but have meandered a little. And maybe less on the theoretical side, but who knows. Thanks for this.
kronos29296 9y ago
Nice comprehensive list. Scares the heck out of me. The only stuff I recognize are the ones I learnt in college (math and some basic physics like EM and stuff). The rest is just plain scary. Makes me really respect Physicists. If this is just to get started then being a physicist is a lot of hard work.
quocble 9y ago
Don't try, most of them go into QUANT Finance.
Stasis5001 9y ago
For reference, generally people learn all this over four years of undergrad and probably the first few years of grad school (I have a BS in physics, and a PhD in a different field, so not 100% sure on the grad school work). That's 6 years of more or less full-time work, surrounded by excellent peers and mentors, where every week you read 2-4 chapters and do 10 problems per chapter. If you're motivated and talented, you'll breeze through the first few years of problems, but anecdotally, everybody hits a wall where the problems start to get really hard. I have no doubt you can replicate the undergrad education through self-study, and maybe even save money and time, but after that point, why not just go to grad school? You won't save much time doing it on your own, and you get mentorship, exposure to the research aspect (not exactly trivial to learn), credibility, and funding. I'm pretty sure the number of high-quality researchers in theoretical physics, or any major field, who are totally self-taught is really quite small. This website feels like it's in part to dissuade amateurs from sending their "awesome result" to professionals, which the author mentions in the intro.
- paulpauper 9y ago
  I'm pretty sure the number of high-quality researchers in theoretical physics, or any major field, who are totally self-taught is really quite small. I think it's zero
  - santaclaus 9y ago
    It is rare (Ramanujan), but happens! [1] [1] https://en.wikipedia.org/wiki/List_of_autodidacts https://en.wikipedia.org/wiki/List_of_autodidacts
  - sn9 9y ago
    I know of at least one professor in Canada (Toronto maybe?) who was self taught and got into a graduate program on the strength of a letter of recommendation from a physicist he had been corresponding with. Can't remember the name at the moment, but I think his background had been in art. And then there's Ed Witten, who studied history and linguistics. It's not really clear when or how he studied physics (so very possibly self-taught), though he had a famous physicist father so he would have had a ready source of advice on textbooks, etc.
projectramo 9y ago
Okay, how do you become a Good Actual Physicist?
- cja23 9y ago
  Just in case you are not joking and for anyone not familiar with the terminology: Physics, and a lot of the hard sciences, are often broadly divided into "theoretical" and "experimental" halves. Experimental physicists design and run experiments, i.e. they "get their hands dirty", or at least the hands of their graduate students and post-doctorates. Their end goal is to find some actual fact about the actual universe, usually a quantified measurement. Theoretical physicists, on the other hand, create theories: mathematical and conceptual models that hopefully explain how or why the universe is the way it is. Ideally, the created theory not only explains the measurements that the experimental physicist has already observed, but also predicts the results of new measurements not yet observed.
paulpauper 9y ago
imho, I would start with general relativity. Most of the other stuff follows from it and you can pick up the other stuff as you go once you understand tensors and functional differential equations.
- mobieus_jay 9y ago
  I would doubt so. I don't think you will ever understand general relativity if you don't have a good grasp on classical mechanics and classical electrodynamics. Tensors and functional differential equations are still profound even though you might know vector calculus.
adarsh_p 9y ago
This is a good collection of resources, but even more valuable would be the syllabi and homework sets from graduate-level theoretical physics courses, which can guide the interested learner through the vast amount of material, and help them gauge what is a reasonable pace of progress and not get bogged down (this has happened to me whenever I've tried to self-study from textbooks). Source: Just got my PhD in theoretical high energy physics.
quantum_state 9y ago
Very nice to see this conversation ... The list is nice and reasonably comprehensive ... it may seem long but it is not as daunting as it looks ... would like to think it is a guidance ... knowing the material does not mean one would become a good theoretical physicist, not knowing all of them does not mean one cannot become a good physicist. Since physics is an experimental science, it makes sense to know in a bit of detail how the observed facts are connected to gain one's own intuition ... this would help to make the list seem short and things become natural ... it also makes sense to know the landscape of the fields and the people in the community ... this will help one to avoid reinventing the wheel or wander into the wild with no return (to reality :-)) ... keeping these in mind, one should be able to enjoy physics or even do something meaningful at some point ...
sn9 9y ago
There's also the Chicago Undergraduate Physics Bibliography: https://www.ocf.berkeley.edu/~abhishek/chicphys.htm https://www.ocf.berkeley.edu/~abhishek/chicphys.htm
hudibras 9y ago
Piece of cake.
hololight 9y ago
Put in some decent range time, and don't underestimate crouch-jump practice
xchip 9y ago
Physicist here, I am sad to say that all the theoretical physicists I know are teaching physics/math to first year undergraduates. What a waste of smart people. All the jobs they could do are already taken by very old people(+65) that refuse to retire.
mobieus_jay 9y ago
IMHO, pick a theoretical field you like and you focus on it. Theoretical physics doesn't mean particle physics or relativity. Every field in physics can be both theoretical and experimental. I got a graduate degree in theoretical physics, focusing on condensed matter physics. To be exact, I model the phenomenon called quantum solid, using Ginzburg-Landau theory.

157 points by seycombi 9y ago

It's a good comprehensive list, but considerably biased by the author's research interests. There are lots of good theoretical physicists that don't know much about the specifics of string theory and haven't seen general relativity since the relevant graduate course, it just depends on the field you decide to specialize in. On the math side, aside from a few things very specific to string theory, most of it is useful throughout modern theoretical physics, and it certainly helps to have at least a passing familiarity with all of the subjects listed for general erudition. The list could also be expanded with lots of things on the computational side that aren't immediately useful to string theorists but are used in many other fields. Disclaimer: just a theoretical physics postdoc, YMMV.

komali2 9y ago

>Unfortunately, I still have to recommend to buy text books as well Why? EDIT: Why buy textbooks, rather than read online resources and online textbooks?

archgoon 9y ago
There is a huge amount of information that has been written down. Different authors have different explanations and takes on things, and will emphasize different aspects of a topic in their presentation. Look at the recommended texts section: http://www.staff.science.uu.nl/~gadda001/goodtheorist/texts&resources.html http://www.staff.science.uu.nl/~gadda001/goodtheorist/texts&... He doesn't just cite one text on Classical Mechanics, he cites 5, and in his section on internet resources http://www.staff.science.uu.nl/~gadda001/goodtheorist/classmech.html http://www.staff.science.uu.nl/~gadda001/goodtheorist/classm... He cites 3 more courses. There is a lot of depth in any of these topics, and any given presentation will be a single path, of many, through the topic. Different perspectives are valuable, as they also help clarify the core of the topic, and allow you to find your own perspective. We are fortunate that there are people who have invested the effort to put some of these resources online, but not everything is currently on the internet. One day perhaps. Also, some of the internet resources that he links to are now gone, and may or may not have been archived. Textbooks that are cited are almost certainly guaranteed to be available through some library. Given that he's also advocating that serious students attend University, proposing books to read that students can access through ILL seems reasonable.

komali2 9y ago

http://www.staff.science.uu.nl/~gadda001/goodtheorist/primarymathematics.html http://www.staff.science.uu.nl/~gadda001/goodtheorist/primar... I wonder, for someone like me that got a pretty terrible math education, how these free courses stack up against just using khan academy or similar.

kronos29296 9y ago
Some of the basics - Khan academy is easy to understand and gives a good foundation. Don't even try to compare the advanced stuff. Just don't. Takes a lot of work and takes years. Even grad students run away from some of the stuff.
- signa11 9y ago
  indeed. here is an article that was posted here not so long ago : http://m.nautil.us/issue/43/heroes/what-does-any-of-this-have-to-do-with-physics http://m.nautil.us/issue/43/heroes/what-does-any-of-this-hav...
- pvg 9y ago
  The stuff linked on the page is stuff you'll learn as an undergrad or before.
  - Retric 9y ago
    'Learn' can be fuzzy. IMO, most undergrads taking an undergrad DifEq course will have little understanding of what they are actually doing and just treat it as symbol manipulation. I have seen people encounter the same problem with calculus, matrices, or even simple algebra. And you can keep pushing, but at some point if you want to progress you need to revisit older topics and hopefully gain new understanding. It's like revisiting multiplication and division in binary and suddenly understanding why a similar process in base 10 works. PS: Pure symbol manipulation is still powerful, but intuition takes a little more.
    - pvg 9y ago

kazanz 9y ago

I would love to see similiar sites set up in other disciplines of various knowledge bodies: Politcal science, economics, philosophy, computer science, etc

kiliantics 9y ago
Yeah, an Econ one is badly needed for all the libertarian economics experts

52-6F-62 9y ago

This is exactly like what I've been looking for -- a bit of a roadmap leading up to [hopefully] returning to school. I've started, but have meandered a little. And maybe less on the theoretical side, but who knows. Thanks for this.

kronos29296 9y ago

Nice comprehensive list. Scares the heck out of me. The only stuff I recognize are the ones I learnt in college (math and some basic physics like EM and stuff). The rest is just plain scary. Makes me really respect Physicists. If this is just to get started then being a physicist is a lot of hard work.

quocble 9y ago

Don't try, most of them go into QUANT Finance.

Stasis5001 9y ago

For reference, generally people learn all this over four years of undergrad and probably the first few years of grad school (I have a BS in physics, and a PhD in a different field, so not 100% sure on the grad school work). That's 6 years of more or less full-time work, surrounded by excellent peers and mentors, where every week you read 2-4 chapters and do 10 problems per chapter. If you're motivated and talented, you'll breeze through the first few years of problems, but anecdotally, everybody hits a wall where the problems start to get really hard. I have no doubt you can replicate the undergrad education through self-study, and maybe even save money and time, but after that point, why not just go to grad school? You won't save much time doing it on your own, and you get mentorship, exposure to the research aspect (not exactly trivial to learn), credibility, and funding. I'm pretty sure the number of high-quality researchers in theoretical physics, or any major field, who are totally self-taught is really quite small. This website feels like it's in part to dissuade amateurs from sending their "awesome result" to professionals, which the author mentions in the intro.

paulpauper 9y ago
I'm pretty sure the number of high-quality researchers in theoretical physics, or any major field, who are totally self-taught is really quite small. I think it's zero
- santaclaus 9y ago
  It is rare (Ramanujan), but happens! [1] [1] https://en.wikipedia.org/wiki/List_of_autodidacts https://en.wikipedia.org/wiki/List_of_autodidacts
- sn9 9y ago
  I know of at least one professor in Canada (Toronto maybe?) who was self taught and got into a graduate program on the strength of a letter of recommendation from a physicist he had been corresponding with. Can't remember the name at the moment, but I think his background had been in art. And then there's Ed Witten, who studied history and linguistics. It's not really clear when or how he studied physics (so very possibly self-taught), though he had a famous physicist father so he would have had a ready source of advice on textbooks, etc.

projectramo 9y ago

Okay, how do you become a Good Actual Physicist?

cja23 9y ago
Just in case you are not joking and for anyone not familiar with the terminology: Physics, and a lot of the hard sciences, are often broadly divided into "theoretical" and "experimental" halves. Experimental physicists design and run experiments, i.e. they "get their hands dirty", or at least the hands of their graduate students and post-doctorates. Their end goal is to find some actual fact about the actual universe, usually a quantified measurement. Theoretical physicists, on the other hand, create theories: mathematical and conceptual models that hopefully explain how or why the universe is the way it is. Ideally, the created theory not only explains the measurements that the experimental physicist has already observed, but also predicts the results of new measurements not yet observed.

paulpauper 9y ago

imho, I would start with general relativity. Most of the other stuff follows from it and you can pick up the other stuff as you go once you understand tensors and functional differential equations.

mobieus_jay 9y ago
I would doubt so. I don't think you will ever understand general relativity if you don't have a good grasp on classical mechanics and classical electrodynamics. Tensors and functional differential equations are still profound even though you might know vector calculus.

adarsh_p 9y ago

This is a good collection of resources, but even more valuable would be the syllabi and homework sets from graduate-level theoretical physics courses, which can guide the interested learner through the vast amount of material, and help them gauge what is a reasonable pace of progress and not get bogged down (this has happened to me whenever I've tried to self-study from textbooks). Source: Just got my PhD in theoretical high energy physics.

quantum_state 9y ago

Very nice to see this conversation ... The list is nice and reasonably comprehensive ... it may seem long but it is not as daunting as it looks ... would like to think it is a guidance ... knowing the material does not mean one would become a good theoretical physicist, not knowing all of them does not mean one cannot become a good physicist. Since physics is an experimental science, it makes sense to know in a bit of detail how the observed facts are connected to gain one's own intuition ... this would help to make the list seem short and things become natural ... it also makes sense to know the landscape of the fields and the people in the community ... this will help one to avoid reinventing the wheel or wander into the wild with no return (to reality :-)) ... keeping these in mind, one should be able to enjoy physics or even do something meaningful at some point ...

sn9 9y ago

There's also the Chicago Undergraduate Physics Bibliography: https://www.ocf.berkeley.edu/~abhishek/chicphys.htm https://www.ocf.berkeley.edu/~abhishek/chicphys.htm

hudibras 9y ago

Piece of cake.

hololight 9y ago

Put in some decent range time, and don't underestimate crouch-jump practice

xchip 9y ago

Physicist here, I am sad to say that all the theoretical physicists I know are teaching physics/math to first year undergraduates. What a waste of smart people. All the jobs they could do are already taken by very old people(+65) that refuse to retire.

mobieus_jay 9y ago

IMHO, pick a theoretical field you like and you focus on it. Theoretical physics doesn't mean particle physics or relativity. Every field in physics can be both theoretical and experimental. I got a graduate degree in theoretical physics, focusing on condensed matter physics. To be exact, I model the phenomenon called quantum solid, using Ginzburg-Landau theory.