Science without Determinism

[cfgauss]

Originally Posted By: Student of Trinity

But there are plenty of opportunities for longer independent projects on basic topics that get written up into an undergrad thesis. For instance, although this wasn't a thesis, I learned an awful lot from an advanced one-semester lab course that had me design and carry out a single simple experiment from scratch, instead of simply following directions with pre-fab apparatus for a weekly lab.

That's good. AFAIK, there wasn't an opportunity to do any experimental stuff at my undergrad university like this, other than building stuff in the basement for someone else's experiment.

Although I got to write a nice string theory paper as an undergrad, and I definitely learned a lot more than any class doing that.

Quote:

Post-docs in physics are normally paid quite decently, and allow you to do independent research. In fact, you don't have to do anything else: no teaching, no grant proposals, no committee work. You're nobody's slave. Apart from the fact that you're under huge pressure, because your academic career will grind to a halt in a year or two if you can't generate impressive enough publications before then, it's a good life. In active fields in which a PhD has good industry opportunities, it's easy to get post-docs. In fields like string theory, it's the wall of fire.

That sounds good. Although I've heard of several theory people doing postdocs ~10 years, too, though. Although I'm hoping that strings now having some nice applications in nuclear/condensed matter stuff that it may make it a little easier for me to get somewhere. I've heard of a lot of good string people around here having a lot of trouble recently...

[Celtic Minstrel]

Originally Posted By: The Mystic

Actually, it wasn't so much the textbook that deterred me from taking the class, though it was a factor. What really turned me off was the name of the instructor listed in the class schedule; he had a reputation for assuming that you've read the textbook before the first class and had understood every word, and that you were taking the class as part of a continuing education program so you could keep your cushy desk job. He also had a serious dislike for undergrad students.

...wow. One wonders why he believes there is any point in teaching the class at all, if that's what he expects.

[Student of Trinity]

Unfortunately it's the one criticism of string theory that has always seemed to me to be quite unanswerable, that it is economically unsustainable. It's quite obviously a good enough idea to be worth studying, but there's not much practical urgency at the Planck scale, and so the appropriate level of human investment in string theory research is low. A handful of brilliant people is all the field really needs or deserves, and it has been operating near or above that quota for some time. So the chances of any new PhD in string theory being able to make a career out of it are, I'm afraid, distinctly slimmer than in other fields in physics.

 

I'm also afraid that applications of strings to condensed matter probably won't help much with this: they'll make string theory groups work on what they consider to be CM applications, but they won't make the much more numerous CMT groups start hiring string theory post-docs. In the unlikely event that a CMT group decided strings were worth a major investment, they would make it by learning string theory themselves.

 

It's still better to work on something you love, and if that's string theory, go for it. But if there's any chance that the things you really love in string theory might also be found elsewhere, that would be worth looking into, because it could make your life a lot easier.

[cfgauss]

Uhh, but string theory really isn't about plank scale physics any more than condensed matter is about relativistic particles? It uses tools where you have to know about those things, but those tools are still useful very far away from those limits.

 

The point of string theory is that there's a great deal about the standard model and field theories in general that aren't well understood. And string theory provides easy answers to those things.

 

I mean, the historical development of string theory really only had things like extra dimensions and tiny length scales as accidental consequences. String theory isn't used in hydrodynamic calculations at RHIC for nothing!

[Student of Trinity]

If this is the new line for selling string theory, I'm afraid it's a little weak. I'm sure it's true enough that strings can be used as a tool for QCD calculations, at least phenomenologically. Nuclear physics is where string theory began, after all. But providing one specialized theoretical tool for the narrow academic topic of quark matter, which is itself only the small rump successor state to the dead empire of nuclear physics, is not a big ecological niche. String theory will get and deserve more support for trying to unlock quantum gravity than it will get for producing a few more papers modelling RHIC data.

 

Conceivably there are a few nice insights to be had from string theory on other subjects that use quantum field theory. But this is solution-in-search-of-a-problem talk, here; nobody in other fields is wringing their hands waiting for strings. So we're looking at maybe a dozen pretty arcane theory papers along these lines, not a blue ocean of opportunity that will create new jobs for string theorists. The existing body of tenured string theorists will probably squeeze all the juice out of applications to low energy physics within a few years. Or at any rate, everyone will think that they will.

 

If applying string insights at lower energies interests you, though, that could be a great career move. It will need learning the native languages, rather than seeing everything through the lens of strings, and developing credentials within the low-energy communities (publishing in Phys Rev A,B or C instead of D; presenting posters at non-string meetings). A string theorist won't go far outside string theory, but an ex-string-theorist can do great things. That doesn't necessarily mean actually quitting string theory, but it means acquiring an independent body of expertise such that people in other fields can see you as one of themselves, who happens to have an esoteric background or sideline, rather than as a string theorist trying to work on their problems.

[cfgauss]

That's hardly a "new line." It's what's been said all along. In all of my studying strings, I've read almost nothing on string theory's predictions about planck scale effects or quantum gravity at all.

 

In fact, the whole point of string theory is that it provides more ways to understand things from field theory. It's hardly a solution in search of a problem, anymore than understanding field theory to work with the standard model is a solution in search of a problem!

 

There are several string theorists who work in other communities using string theory to help understand their fields... there are whole textbooks about these kinds of things. And you don't really have to go outside your body of knowledge to to this anyway, since to learn string theory properly you would be exposed to most of it already.

 

Most of the abstract stuff in string theory is based on understanding what the structure of strings, just like the 10s-80s was all about understanding the structure of quantum mechanics and field theories.

 

In fact, people made the same kinds of claims as you're making when people like dirac were talking about QM in terms of Hilbert spaces .

[The Mystic]

Originally Posted By: Celtic Minstrel

Originally Posted By: The Mystic

Actually, it wasn't so much the textbook that deterred me from taking the class, though it was a factor. What really turned me off was the name of the instructor listed in the class schedule; he had a reputation for assuming that you've read the textbook before the first class and had understood every word, and that you were taking the class as part of a continuing education program so you could keep your cushy desk job. He also had a serious dislike for undergrad students.

...wow. One wonders why he believes there is any point in teaching the class at all, if that's what he expects.

Or, for that matter, why he was even teaching undergrad classes at a community college that only offered associate's degrees.

[Student of Trinity]

Originally Posted By: cfgauss

There are several string theorists who work in other communities using string theory to help understand their fields... there are whole textbooks about these kinds of things.

The question is how much this work is valued by the other communities.

Originally Posted By: cfgauss

And you don't really have to go outside your body of knowledge to to this anyway, since to learn string theory properly you would be exposed to most of it already.

It takes more than brief exposure to a topic to make original contributions to research in it. No lake looks deep from the shore.

Let me put it this way. I don't recall any Phys Rev Letters in the past ten years showing important string results in condensed matter or AMO physics, or predicting anything that might be observed soon at CERN. Did I miss some? Or is what you consider broad application to other fields still something I'd call very narrow and limited?

Edit: about the newness of the line. My contact with string theory faded from fairly close second hand to nil, between ten years ago and five years ago. But string theory is now 25 years old as a major topic. Over most of its history, the one argument string theorists gave for their subject was that it seemed capable of reconciling quantum mechanics and gravity.