Couple of questions regarding theoretical physics

[Akirus]

I'm currently looking to major in theoretical physics/astrophysics for my undergraduate studies next year and I have a few questions about it that I'd like cleared up. At the moment, I'm a year 12 Australian high school student and I'm trying to decide exactly where and what I want to study at tertiary level. My main areas of interest are theoretical particle physics (mathematically rigorous areas of study like string theory) and various aspects of astrophysics, in particular research into physical cosmology. Dark matter/energy and topics pertaining to large celestial bodies like collapsing stars, black holes, etc interest me a lot. I also love the prospect of learning and using very advanced mathematics.

Is the mathematics used in advanced theoretical physics (in particular, stuff like supersymmetric string theory, etc) more applied or pure maths? I haven't actually done any higher level physics studies, so my motivation to do the subject is mainly from pure interest, with what I know mostly derived from wikipedia reading.

I'm also curious how 'research' in theoretical physics works both on an undergraduate level and in graduate studies and beyond (i.e. academic research). Am I right in assuming that since it's theoretical, I don't actually have to use any research facilities, etc. to conduct experiments? My impression of theoretical physics is that its mainly thinking, maths and computational calculations, etc. I hate actually doing anything practical, so this is quite important to me.

Continuing that point, are studies in theoretical astrophysics/cosmology similar to theoretical physics? Is it the same line of work but in a different context? What are the main differences between the two? Being that I haven't had much opportunity to delve deeply into these topics, I figure that I should probably take both during my BS and decide my specialization during honors.


If all these questions have been answered somewhere, a quick reference would be appreciated; I've been doing a lot of searching but haven't really found any information to iron out the finer details. I also have a few more questions but I notice the volume of this post is starting to become excessive, so thanks in advance for reading my questions.

 

[Jack21222]

You're trying to plan out your entire physics career before you've taken a single "real" physics class. High school doesn't count. My suggestion would be to relax and just taking your intro classes before trying to lock yourself into one area.

This is a marathon, not a sprint.

 

[Akirus]

Noted. However, rather than trying to lock myself into one area, I'm really just trying to get an idea of where I am trying to go and whether or not I will actually enjoy it. Moreover, it will affect my decision as to the university I choose to attend next year. Which questions in particular are more specific than I need to know?

 

[wasia]

I can only answer about 'practical' things and only approximately. After you graduate and start doing research, specialization prevails, hence one most likely does only experiments, or only theoretical work ~ calculations/modelling . However, in undergrad studies, a lot depends on the curriculum of the study program you choose. I would recommend doing at least some lab work, because you never know - perhaps you will start liking it at some point (doing an informed decision is always better!). Moreover, it could be useful for your physical intuition later on.

If I were you, I would try to taste a bit of everything and specialize as late as possible.

 

[Akirus]

I am planning to take a double major in mathematics and physics at undergraduate level, which allows me to leave the decision for specialization until my honors year (3rd or 4th year of uni, after B.S). The universities I'm interested in have compulsory lab components for 2 years, so I'll definitely be getting some experience there.

When I asked the question regarding mathematics, I was working under the assumption that I had to choose a specific major, so in this case, either pure mathematics or applied mathematics. Now I am given to understand that the major itself isn't that important, so I should just choose the appropriate subjects relevant to my physics instead. Is this assumption correct?

 

[wasia]

Yes, I think it is correct. I find the list of what Maths one needs for Physics in 't Hooft's http://www.phys.uu.nl/~thooft/theorist.html" quite good.

 

[twofish-quant]

Is the mathematics used in advanced theoretical physics (in particular, stuff like supersymmetric string theory, etc) more applied or pure maths?

Physicists tend to think in ways that are very, very different from mathematicians. Mathematicians tend to think in terms of proofs whereas physicists tend to think in terms of analogies. Also, some fields are extremely computational.

I haven't actually done any higher level physics studies, so my motivation to do the subject is mainly from pure interest, with what I know mostly derived from wikipedia reading.

Some of the math pages on wikipedia are quite good.

Am I right in assuming that since it's theoretical, I don't actually have to use any research facilities, etc. to conduct experiments? My impression of theoretical physics is that its mainly thinking, maths and computational calculations, etc. I hate actually doing anything practical, so this is quite important to me.

For some areas of theoretical physics you need a lot of computer cycles. Also you need a lot of people with different ideas in one area so that people can swap ideas. Science is intensely social. The other thing that is important in "real science" is finance and management. Putting together a research institute is very difficult, and someone needs to keep track of the money and personnel issues.

Also, you'll find that most of the challenges in doing physics turn out to be quite "practical." You spend a lot of your time debugging code, or in a library doing literature searches, or just crafting a paragraph in a journal article to be just right.

 

[djeikyb]

Another point- deciding exactly what branch of physics you want to do for the rest of your life at tihs point in your education is essentially pointless. As an undergraduate, you won't even get to take classes in specific branches of physics (i.e. particle physics, condensed matter, AMO, etc) until your senior year.

And yes, theoretical physics (and even experimental physics) is mathematically rigorous. At OU, the physics program involves harder math than the math program. The math is a mixture of pure and applied math, though you will want to take as much math as physically possible if you really want to do theory work. Higher math classes such as Abstract Linear Algebra and Partial Differential Equations are an absolute must.

Your desired specialization of physics probably shouldn't be the final deciding factor on where to study. As an undergraduate, you will likely only be able to take a few classes towards that specialization, and probably won't get to do that until your senior year. HOWEVER, working with a professor is absolutely invaluable. It provides a (sometimes paid) opportunity to learn higher physics and to obtain extremely valuable experience. You also might be surprised how easy it is to get a research job- I went up to my Intro to PHysics II professor my freshman year and asked him about a job. I started work for him the following week.
Working with a professor also gives you a taste for different fields. You are not committed to working for the same professor for your entire undergraduate experience.

 

[Akirus]

Physicists tend to think in ways that are very, very different from mathematicians. Mathematicians tend to think in terms of proofs whereas physicists tend to think in terms of analogies. Also, some fields are extremely computational.



Some of the math pages on wikipedia are quite good.



For some areas of theoretical physics you need a lot of computer cycles. Also you need a lot of people with different ideas in one area so that people can swap ideas. Science is intensely social. The other thing that is important in "real science" is finance and management. Putting together a research institute is very difficult, and someone needs to keep track of the money and personnel issues.

Also, you'll find that most of the challenges in doing physics turn out to be quite "practical." You spend a lot of your time debugging code, or in a library doing literature searches, or just crafting a paragraph in a journal article to be just right.

I think the thing with physicists/mathematicians sounds more or less suited to my interested. I like maths, but not so much maths for the sake of it.

I'm not sure what you're getting at with the finance; are you implying that I should also take finance subjects if I want to be an academic, or that it's something to consider as an entirely separate occupation?

When I said 'practical', I meant things more like laboratory work, performing experiments, etc. The things you mentioned sound fine to me, more or less what I expected.

Another point- deciding exactly what branch of physics you want to do for the rest of your life at tihs point in your education is essentially pointless. As an undergraduate, you won't even get to take classes in specific branches of physics (i.e. particle physics, condensed matter, AMO, etc) until your senior year.

And yes, theoretical physics (and even experimental physics) is mathematically rigorous. At OU, the physics program involves harder math than the math program. The math is a mixture of pure and applied math, though you will want to take as much math as physically possible if you really want to do theory work. Higher math classes such as Abstract Linear Algebra and Partial Differential Equations are an absolute must.

Your desired specialization of physics probably shouldn't be the final deciding factor on where to study. As an undergraduate, you will likely only be able to take a few classes towards that specialization, and probably won't get to do that until your senior year. HOWEVER, working with a professor is absolutely invaluable. It provides a (sometimes paid) opportunity to learn higher physics and to obtain extremely valuable experience. You also might be surprised how easy it is to get a research job- I went up to my Intro to PHysics II professor my freshman year and asked him about a job. I started work for him the following week.
Working with a professor also gives you a taste for different fields. You are not committed to working for the same professor for your entire undergraduate experience.

Yeah, I understand what you mean. However, at the moment (I'm in Australia) my choices are more or less between Monash University or ANU (Australia National University); Monash is closer to my place of residence, whereas ANU is interstate. Both of the degrees I want to apply for are accelerated research-oriented degrees, but I hear ANU has more opportunities for research in theoretical physics and its degree is more internationally renowned, which I assume would be more helpful in applying to top universities in America once I graduate.

I'm not particularly big on the idea of moving to Canberra (different state) next year, although the main concern is, like you said, chances to get research jobs and projects at undergrad level.

People also say that the physics/maths departments at Monash aren't as good as ANU either, so I'm really not sure what to do. How much does it matter? Is it okay as long as the important subjects are covered?

Oh, and just one more question... is it reasonably possible to learn GR/QFT/ST within 2 or 3 years? I'm thinking of doing advanced self-study so I can learn these things by the time I do my honors year. Someone recommended that I self-study my material around 1 year in advance, so I'm just curious as to how far I should take this. Other than feasibility, is it advantageous in terms of application to graduate schools to have this level of knowledge, or even an honors thesis on it?

Thanks for the help.

 

[Akirus]

Additionally, just found out that GR/QFT isn't taught at Monash until honors year, whereas string theory studies are available in 3rd year of the undergraduate at ANU.

Not really sure what to do, would appreciate advice.