The Spacetime Metric
Monday, May 14, 2007
  spherical harmonics
It's hard to become a physicist. If it were easy, everyone would do it. You have to take several years of math- and understand it almost viscerally- plus many years of required and then specialized physics courses, and then everything else. The "everything else" is the easy part; there's a popular list entitled "You Know You're a Physics Major If..." which contains the entry: "You consider any non-science course 'easy.'"
In order to reverse the contemporary downward spiral of physics knowledge, we need more physics majors. We need physicists who can tell the difference between string theory and everything else, between science and pseudo-scientific fads (like global warming theories). The "problem", the trouble with physics, is that there aren't enough of us, not that there are too many of us.
There's a shortage of people with any technical knowledge, but physicists have been hit the hardest. Graduate students are being forced to work long hours at CERN; even the largest physics lab in the world has had its share of problems. I hope the LHC's startup date doesn't get pushed until next year. With all of the problems in experimental (not to mention theoretical) physics, many physicists are advising their students to leave the field. And I'm afraid a lot of them will.
The future physicists who remain will need support. Not only financial support from NSF grants, but support from people who know what they're talking about. People who know that R(nl)Y(lm) is not only a solution to a spherical-coordinate PDE, but a wavefunction... for example. (R is proportional to r^l, where l is the quantum number corresponding to s, p, d, f, etc. Y(lm) is a Legendre function with a somewhat complicated generating formula. For example, Y(00), which has l=m=0, is (1/4*pi)^1/2.) The general public needs more than an extremely vague knowledge of what physics is.
I was the first student from my high school (at least in the last five years) who took a year of quantum physics. That should not have happened. Knowledge of advanced physics is becoming scarce, and I hope scientists never actually reach the point- asymptotically or not- where no one can understand each other.
 
Monday, April 30, 2007
  the end of the postmodern era
Those who convey misinformation (according to Lubos Motl) about theoretical physics have, unfortunately, fallen victim to postmodernism. In fact, The Trouble with Physics is now described as a postmodernist book.
If the final theory is unknowable, it doesn't make sense to become a theoretical physicist anymore. The final theory is THE FINAL THEORY. Once it is formulated entirely into physical law, that's it. The end. What will happen once we achieve "physics nirvana"? I don't know, and it doesn't do any good to speculate.
Postmodernists, on the other hand, like to think that we can't achieve that state. They attack science for the usual unintelligent reasons. The worst thing about it is that most postmodernists are too lazy to learn anything about science; hence they created their own depressing field of study. Most of them chose majors that had no practical purpose, anyway.
Postmodernists are the reason why science (and a whole lot of other things) are suffering now. They create confusion so that people who try to end confusion (e.g., scientists) will become rather annoyed with them. Postmodernists are the scourge of academia.
The postmodern era, however, may have just ended. Or at least it will end this year, when the LHC starts up. We shall return to the modern era again. Physics, space exploration, legitimate climate science (not global warming "theories") should return to the way they were about 35 years ago, when all of the above were thriving.
And that's the memo.


 
Thursday, April 19, 2007
  chemistry is physics
I haven't posted on here in more than a month, but that's because I didn't think anything particularly interesting was going on in physics. Now there is.
I remembered this article and realized that the word "stupid" is loaded and inaccurate, but there are many other things in the article that are true. Are physicists unable to observe complexity, if complexity even exists (or is another loaded word)?
The tone of this article suggests that physics might be an "easy way out", to avoid seemingly more challenging problems. Umm... physics is not the easy way out; it never has been. It's actually the hardest way out.
What Prof. Rancourt probably meant to say was that physicists spend too much time on very complicated problems, causing them not to be able to solve easier ones. I know a lot of mathematically gifted people who have to constantly double-check their arithmetic, because it's the arithmetic (not the calculus or higher-level math) that they might mess up. I've had a lot of experience with that in every physics course I've taken here. It's not the professors' faults; it's just that really smart people make a ton of errors (particularly in arithmetic)!
To circumvent that difficulty- if I ever become a professor- I want to know absolutely everything that I will teach the students before I teach the first class in a course. I don't want to make those errors, or try to remember what the form of such-and-such wavefunction is. I don't want to write a textbook and then clean up my own mess by writing a 40-page "errata" appendix.
This symptom of physicists and other mathematically-inclined people has led some physics departments to offer "more practical" courses like Physics for Future Presidents. You don't have to know what a Green's function is; you just have to know how to calculate square roots. No calculus or even algebra is assumed.
Why do we need courses like this? I don't know, but if you can offer the correct answer, I'll nominate you for the Nobel Prize (assuming I ever get to do that).
This disease of being unable to do "easier" calculations has led some physicists into the dark realms of anti-string theory propaganda and "stop global warming" thoughts. In trying to uncover the ultimate secrets of the universe, you're glossing over the more obvious truths, e.g.:
1. Global warming on a macroscopic scale is a myth.
2. The anthropic principle is a sensible addition to any grand unified theory.
3. String theory is the best candidate for a GUT.
4. In order for there to be a scientific consensus, 100% of scientists have to agree on something. Not 80% or whatever the politricks claim the global warming consensus is.
5. Climatology and LQG are two fields of science that started out attractive but rapidly turned ugly (well, climatology is far worse). At least LQG is based on quantum theory, whereas climatology is hardly better than alchemy.
The point is that even physicists are being seduced by bad ideas. Some of them ignore the more obvious facets of reality.
I think physicists should be required to take more biology and chemistry than they usually have to. Not because biology and chemistry will get you closer to the GUT (they don't) but because they're not so abstract. Physicists should know how chemists use simpler approximations to solve "more complicated" problems, e.g. atoms with atomic number Z > 1. Solving the helium atom using perturbation theory/ the variational method can get awfully tedious, unless you use chemistry.
To study covalent bonding in the hydrogen molecule ion (which isn't "complex" at all) you have to diagonalize the Hamiltonian matrix with components <1|h|1>, <1|h|2>, etc. (the kets can be in an n-dimensional basis, although typically you'll just use 2 and create a 2x2 matrix). The elements <1|2> and <2|1> do not give 0, so you end up with a matrix that can't be diagonalized very easily. After a lot of handwaving (and only then) you end up with energy eigenvalues (H11 plus/minus H12)/[1 plus/minus <1|2>]. Even a relatively simple problem like that takes a long time to solve, particularly if you're using a 5-dimensional basis to get a 5x5 matrix, for example.
I just think physicists would do better if they knew easier methods. Solving problems the ridiculously hard way is "the trouble with physics."
 
Friday, March 09, 2007
  when the detractors are away
Now that one detractor is away for the next week and a half, a lot more pro-string blog posts will be written. This, obviously, is one of them.
I explored the physics department at Rutgers yesterday in order to find out about their graduate programs in high energy/string and condensed matter physics. Apparently they only have about a dozen professors and just slightly more graduate students in high energy theory, with only around half of the aforementioned concentrating in string theory. The numbers in condensed matter theory and experiment (each) are about the same as in high energy theory. Even at a very large university with a lot of physics professors, clearly not "everyone" is concentrating in string theory.
So, what is groupthink? I think it's evident that groupthink is a Lie group (additional meaning intended). Not everyone is dropping what they're doing in order to concentrate on some untestable figment of pseudo-mathematicians' collective imagination.
After the LHC is completed, theoretical physics will become more data-driven. The high-energy physicists I talked to seemed very excited over this (understandably) since phenomenology will play a greater role. After the success of the Standard Model and the (electroweak) unification of electromagnetism with the weak nuclear force earned three physicists the Nobel Prize in 1979, there really haven't been too many exciting breakthroughs in experimental physics. Phenomenology- connecting theory with experiment- will become more vital than ever once the LHC is finished, particularly if the Higgs boson or extra dimensions are discovered. The high-energy physicists I talked to considered the "extra dimensions" part highly unlikely, but not impossible. Hopefully the physics job market will prosper with more data coming in... more "phenomenologists" will be required.
So, will the LHC discover anything about "loop quantum gravity"? It was evident- from talking to string theorists yesterday- that they were in fact string theorists; LQG to them was "not serious physics" and "bad for young physicists to get involved in" as opposed to "good quantum gravity" or something more serious like AdS/CFT. I got the impression that the reason why more physicists weren't working on LQG was that it was rife with problems. That didn't surprise me at all. Is string theorists' view of LQG disparaging or reflective of "groupthink", or is it a correct, honest view? I would have to agree with the latter.
String theory is based on the foundations of quantum field theory. If you don't know QFT, you can't do very much string theory. (If you don't know math, you can't learn very much physics, even of the classical variety.) QFT extends beyond quantum mechanics, which is based on linear algebra. I am only an undergrad, so I haven't taken a field theory course yet. However, the problems with LQG are obvious even for someone who hasn't taken QFT or who hasn't been "brainwashed" by pro-string PhD advisors yet :)
Quantum mechanics is the study of quantum states. The wavefunction |psi> is the most important of these (the Schrodinger equation equates E|psi> to H|psi>). A wavefunction evolves in time by the equation e^(-iHt/hbar)|psi(0)> = |psi(t)>. Nothing too complicated there (once you get used to bra-ket notation). But QFT is much harder and requires more abstract mathematical techniques. And string theory is based on this, making it harder still. It is an extension of our present knowledge, not something completely "out there" or "not even science anymore." Its critics (especially the bad science journalists whom I've discussed before) don't see this connection.
I hope the LHC will change that.



 
Wednesday, March 07, 2007
  the truth won't set you free
"That man is anti-SUV, and he's pro-terrorist."
Not Even Wrong has reported that Billy Cottrell, a physicist from Caltech, is being mistreated in prison. He was arrested for acts of "ecoterrorism" in March 2004 after destroying SUV's and pulling various other pranks.
It's quite rare that a physicist gets arrested, so one would think that it would cause a stir in the physics community. Cottrell was actually arrested three years ago, but I didn't hear about this until today. The really bizarre (not to mention extremely unjust) thing about this is that he's not permitted to study physics or Chinese in prison, or even to teach the other prisoners calculus. Even Mumia Abu-Jamal was allowed to continue his education in prison, back when he was still on Death Row.
Apparently Cottrell has been victimized for years; he submitted a paper on quantum physics to his sixth-grade teacher but still got an F because the teacher thought it was plagiarized. He had a lot of other problems in high school as well. The cruelty and injustice done to him is unbelievable and unacceptable.
I think he did humankind a great service by destroying those SUV's. No one was inside them; it's not like he killed anyone. Effectively, he destroyed them so that their drivers wouldn't waste their money on those gas-guzzling tanks, or that they wouldn't die when the SUV's flipped over into a ditch.
Maybe it's just my anti-SUV bias...
Anyway, I'm going to explore the graduate physics department at Rutgers tomorrow (where the writer of The Reference Frame got his PhD). They must have an excellent high-energy/ string theory program if string theory's ultimate advocate came from there.
 
Friday, February 23, 2007
  the road less traveled
What is the "trouble with physics"?
A. Too many theories to choose from
B. Not enough real physics jobs
C. Having to compete with stamp collectors (people in other fields)
D. All of the above
The correct answer is (D), and not surprisingly so. As graduation gets closer and closer for many of the physics majors I know, I'm starting to sense an atmosphere of overwhelming despair. Many of them are wondering what they're going to do after graduation; the question, "What do you do with a physics degree?" is getting thrown around a lot. The obvious answer is "go to grad school", but since only about 15 percent of RPI graduates (all majors included) go to grad school, I don't think we're really prepared for it.
These people think- erroneously- that physics should be very similar to engineering. Since there are a lot more engineers than physicists (about 100 times more in America), and since engineers tend to be very specialized even if they just hold a bachelor's degree, people know a lot more about engineers than they do about physicists. Which is ironic, because high schoolers (i.e., those who are trying to figure out their future careers) don't take engineering courses before they go to college. There are very few books for the general public that really delve into the details of what engineers do. So why are there so many times as many engineering majors as there are physics majors?
I don't think the answer is because of job opportunities. The opportunities for engineers certainly aren't perfect, especially because so many jobs are being outsourced. The Capital District of Upstate New York is a perfect example of an area where there had been almost limitless engineering jobs a few decades ago, but over time, everything changed for the worse, contributing to the overall decay of the area.
So what's the answer? Why is physics less popular? The physics majors who lament over the lack of job opportunities obviously haven't heard the laments of liberal arts majors, whose condition is far more pitiful. Physicists may have to go to grad school, but at least we're basically guaranteed to get a skilled job :) (although not necessarily physics-related).
 
Wednesday, February 07, 2007
  on pseudoscience
I've noticed, since the temperatures have consistently remained below freezing here, that there has been somewhat less talk of "global warming." By "somewhat less" I am implying that some people have been going outside for a change. The temperature got up to 293 K at the beginning of January throughout much of the northeast, even in upstate New York, so the usual alarmists went crazy. Now the temperatures have fallen dramatically.
I was quite disgusted to discover that Columbia University is now offering a somewhat new master's program. Not in loop quantum gravity, physics blogging, or anti-string policy... but in "climate and society."
I didn't know it was possible to major in pseudoscience, let alone get a master's in it, but here we go. This example of "groupthink" is far more frightening than anything theoretical physicists could ever come up with. :) Indeed, climatology is an actual example of groupthink, and an alarming one at that.
Fortunately, not everyone is buying this global warming garbage, not even in the climatology community. As the Reference Frame tells us, there have been quite a few papers recently (and a lot more to come) which are trying to convince the groupthinkers that "global warming", if it actually did exist, would not result merely from human activity. It is the opinion of this blogger that anthropogenic global warming theories were developed by Luddites who want to make people feel guilty for wrecking the planet through CO2-emitting technology.
It gets even sadder when you realize that the Kyoto Protocol is costing untold billions of dollars, all of which are being thrown away. If only that money could have gone to legitimate science, to physics research, to something perhaps even more powerful than the LHC (like the ill-fated SSC). I am not as optimistic as Dr. Motl that the LHC will find evidence for supersymmetry a few hours after it starts up, but we desperately need the LHC to continue actual scientific research. The "trouble with physics" is that it doesn't get enough funding and has to resort to less-powerful accelerators. (The SSC would've been about twice as powerful as the LHC.)
If only pseudoscience would make way for real science...
 
A cosmological blog designed to prevent crackpots from ruining professional physics blogs.

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Location: Ocean County, NJ / Rensselaer County, NY, United States

I am an undergraduate at RPI (Rensselaer Polytechnic Institute). I enjoy reading physics blogs because I am working toward becoming a physicist. One of my objectives is to increase scientific literacy, which will prevent crackpots from attacking eminent physics blogs.

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