Below are the 20 most recent journal entries recorded in Andre's LiveJournal:

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Sunday, June 13th, 2004
10:39 pm	High School I was quite annoyed upon reading this article in the Atlantic Monthly. It is a review of three recent books examining teenagerdom and high school from very different perspectives. The one that most interested me was the first, a sociological study. The thing that most irked me about the review was the attitude that the reviewer brought toward his readers, an assumption that we are of course on his side, that the points he is making against the book and its author, Murray Milner, are so obvious to anyone who has gone through an American high school that he need not even defend them. Milner is made out to be an innocent and ignorant sociologist; childlike in making what he imagines to be discoveries but which are self-evident truths known to anyone who isn’t a stick in the mud; one to be patronizingly praised for his sweet good intentions. The reviewer writes, “As his eye turns to pseudonymous ‘Woodrow Wilson High,’ he believes he’s detected an intriguing resemblance: ‘Both Indian castes and adolescent subcultures are systems in which status is the key resource.’ This is certainly stop-the-presses stuff; dare he go further?” I gather he intends this to be sarcasm, but beg your pardon no: I never witnessed, nor was part of, any such system, and I would indeed like to hear news of them. If you already know about them, bully for you, but please don’t treat me like an idiot for growing up in a different social environment. Somewhat later he gives us, “Don’t we all understand that high schoolers’ self-devised categories and peer comeuppances, including the petty cruelties Milner deplores, are just tools for the basic project of adolescence, which is a hunt for identity?” Well, no, to answer your rhetorical question. I can speak only for myself, but if my adolescence may be said to have a “basic project,” it is doing well in my academic work while having some time for fun or relaxation. Even if this search for identity is key (a assertion he doesn’t even attempt to defend), assigning such a range behaviors to it trivializes everything and explains nothing. As the review mentions earlier, many of these behaviors are not present, or are radically different, outside of America. There must be, I think, some complicated interplay of causes for these things, and I would like to know what light the sociologists can shed on them. (13 Comments |Comment on this)
Tuesday, May 11th, 2004
1:09 pm	Spin-1/2 Particles Are the Best My oral exam with Mary went better than I thought it might. We had to read several papers on the EPR paradox of quantum mechanics (the famous “spooky action at a distance”) and give a 20 minute presentation on one of them. It’s really cool to fully understand all the subtleties and mathematical details of such a neat part of quantum mechanics, one of its famous paradoxes that you always read about in popular accounts. Philosophical implications for the nature of reality and all that sort of thing. The fact that there is one week until I leave Reed for the summer has only partly sunk in. So weird, so weird. (2 Comments |Comment on this)
Thursday, April 29th, 2004
7:52 am	Reading about people who have real social problems makes me realize that I should probably stop feeling sorry for myself. http://www.nytimes.com/2004/04/29/national/29SYND.html?th (4 Comments |Comment on this)
Tuesday, April 27th, 2004
3:32 pm	The End is Nigh Running out a gas a bit here at the end of the semester. I frequently feel like this before break, but it seems to have onset five days before the end of classes rather than the usual, say, one or two days. Feeling tired, difficult to find motivation, that sort of thing. Yet, no matter, for I have found strength in the outlook of a runner at the end of a long race: the last 100 m are to be sprinted, and I shall finish in grand style, making my victory all the more glorious! Or something. (Actually I don’t know if that’s a real strategy in races. Good analogy, though.) (2 Comments |Comment on this)
Thursday, April 15th, 2004
8:35 am	Sucked into a swirling vortex Or at least the world of instant messaging. You may direct your comments to nonnormalizable via AIM or to andre.bach@reed.edu via MSN. (2 Comments |Comment on this)
Sunday, April 11th, 2004
10:59 pm	I'm feeling better than this post indicates Have been faring but indifferent well of late, finding bad in what is best. I (or rather, some part of me has) have taken what is now a tradition of some five weeks running, doing something on the weekend with Kevin and Fawntia and perhaps some other, and also the somewhat-new habit of spending more time (as at meals) with the same and made myself sad, or full of misgivings, or otherwise less than happy. Now do I long for, look forward to, or worry over the anticipated time I will spend socializing (the word retains its foul taste to me) with them. Before (as I can remember) I never did fret over such things, but happily spent the weekend or odd meal with no thought as to deliberately spending it with other people. What might be happy thoughts to beguile the tedious night are instead minor torments, constant needles on my mind. What’s worse, though, is that much of that time which is the object of these thoughts ends up being spent in (what seems to me) awkward silence or half-forced conversation. As a topic, “isn’t it funny that we’re all sitting here together in silence” is already played out. At the moment, I’m feeling that it (socializing) is not worth the effort. Knowing myself, though, in some little time I think I shall once more be delighted in it, for I do always go in such cycles. (8 Comments |Comment on this)
Friday, April 2nd, 2004
7:08 am	So early in da moanin' Awoke at 6:30 today. Unremarkable, except that my alarm is always set for 7:30 and I did the same yesterday and, to a lesser extent, several more times these past one or two weeks. I never, ever, used to wake up before my alarm clock on school days, and I’ve been following virtually the same routine these past three and a half semesters. It could just be the greater amount of light in my room in the mornings, which the upcoming daylight savings time should take care of. If it continues to happen, I think I’ll have to take it as a message from my body (god, I feel like such a hippie) that I need to do something differently in how I’m going about my life. (4 Comments |Comment on this)
Sunday, March 28th, 2004
7:57 am	My second Shakespeare paper, completed Friday, is the new record holder for worst-paper-I’ve-written-at-Reed. Eh, you can’t win ’em all. On the brighter side of things, went out with friends (Kevin, Fawntia, David K., Fawntia’s sister) to dinner and rented a movie. This was great fun, most enjoyable indeed. Nothing quite like spending time with one’s friends—an old truth to you, I’m sure, but something which I am still most pleasantly surprised at when it comes up. (That doesn’t provide exactly the feeling I’m trying to convey. [Just so you know.]) David Griffiths’s recommendation of Arsenic and Old Lace was, I think, very well chosen. (Comment on this)
Saturday, March 20th, 2004
7:50 pm	Sexy physics! I got back yesterday from a trip up at the Reed ski cabin with seven others, mostly from the Steele dorm. It was quite fun, and the change of pace was very nice for me. We messed around in the snow (four feet deep! don’t get that in Detroit), cooked for each other (I did dessert), played board (Cranium, LotR Risk, SW Epic Duels, Scrabble) and other games, and relaxed. A game we played (of the sort I am told is associated with slumber parties) went under the moniker “Fantasies.” We each wrote on a slip of paper our name and one of our fantasies, which we then put into a bowl. One person took each of papers in turn and read the fantasy, and we each guessed who’s it was. The votes were recorded, and at the end it was revealed who had what fantasy. That the fantasies be of at least a somewhat sexual nature was implied/required. We played twice, and my two (very lame) fantasies were, “To be with someone much smarter than I am,” and “Sexy physics!” At the time, my conception of sexy physics was nothing more than sexy people doing physics, but I think the idea that they had upon hearing it—physics itself being found sexy—is actually much better. (“Oh Heisenberg, your uncertainty turns me on!”) Since I had just met several of the people on the trip, I decided not to write down any of my really serious fantasies, as that would requiring baring the deepest recesses of my soul and so forth. Oh well, perhaps another time. (Comment on this)
Saturday, March 13th, 2004
1:06 pm	Why Quantum Mechanics Is Cool I’ll attempt to have this make sense to non-mathematical readers. One of the basic cases we’ve studied in quantum mechanics is the quantum simple harmonic oscillator (SHO). It’s the quantum analogue to the mass on a spring moving back and forth in a very simple way that we did in freshman and sophomore physics. The QM problem is much richer (and more complicated). Given this system, the task is to solve the Schrödinger equation (SE) for the wavefunction psi. Psi, once you have it, tells you where the particle can be found and contains all the information about the particle. The SE relates psi, how psi changes with time, and how psi changes with position. Different situations require different techniques to solve the Schrödinger equation. I want to talk about the two ways you can solve the Schrödinger equation for the SHO, which are very unlike each other. The Ladder Method Suppose you have a solution to the SE already, call it psi-n. Now, it’s a feature of problems of this sort that each solution has its own exact, well-defined energy, so call E-n the energy of psi-n. It’s pretty easy to show that there are two related mathematical operations you can perform on any psi that give you a new wavefunction related to psi. One, call it A, takes a wavefunction and gives back another wavefunction with energy greater that the original by a certain amount, which is hbar times omega, call it little e. (Hbar is a fundamental constant of nature and omega is the number that determines how strong the SHO is.) The other, call it A*, gives back a new wavefunction with energy less than the original by the same amount, e. So, from any one solution psi-n (with energy E-n) we can construct infinitely many other solutions, A(psi-n) = psi-n+1 (with energy E-n+1 = E-n + e), A*(psi-n) = psi-n-1 (with energy E-n-1 = E-n - e), and so on. You can imagine a ladder, each rung a wavefunction with height analogous to energy and A and A* moving you up and down. This is great and all, but we don’t have even one solution yet! But wait a moment: if we keep applying A* to each new psi we get, we can make solutions of infinitely negative energy. That doesn’t seem quite right, and indeed it’s not: there’s a neat proof that any wavefunction that could actually represent a real particle must have energy greater than, in the case of the SHO, zero. So the solutions with negative energy gotten from applying A* must not be able to represent a real particle. Call psi-0 the wavefunction with energy E-0 less than or equal to e (we shall see later that there can only be one such wavefunction). We conclude, specifically, that A*(psi-0) is a wavefunction that cannot represent a real particle. There are two ways in which psi can fail to represent a real particle. Recall that psi gives you the probability of finding the particle in different places. Since we’re always talking about just one particle, the probability of finding the particle somewhere has to be exactly one. Psi have fail to have this property in two very different ways: it can say there is an infinite probability of finding the particle at all, or it can say there is a zero probability of finding the particle at all (this is when psi is zero everywhere). There’s an easy way to prove that it’s a mathematical property of A* that it will never yield a wavefunction of the sort that gives an infinite answer. Therefore, we can conclude that A*(psi-0) = 0 for all space and time. From the theory of differential equations, we know that A*(psi-0) = 0 uniquely determines psi-0; there is only one wavefunction that satisfies that equation. As it happens, solving that equation (which is easy) reveals that psi-0 have energy E-0 = e/2. Now we can see why psi-0 is the only wavefunction with energy less then e: any other would have to satisfy A*(psi) = 0, and we know that psi-0 is the only one that can satisfy that equation. Applying A multiple times to psi-0 we can construct an infinite ladder of solutions (denoted psi-n with energy E-n = (n+1/2)e, where n goes from 0 the infinity). From this we can conclude that there are no wavefunctions with energies between those mentioned above; there is only one ladder and it has rungs equally spaced. I think the little argument for this is really neat: if there were a wavefunction of energy between the psi-n’s above, then we could use A* on it to make a wavefunction other than psi-0 with energy less than e, which we know is impossible. Thus we have the “ground state” wavefunction psi-0, and we can make as many a we want from it using A. That means we’ve solved the quantum SHO. Whoo! The Brute Force Method The ladder method was basically a really clever trick based on the very useful properties of A and A*. This method, however, is just the fallback technique used on any differential equation when you can’t think of anything better to do. (It’s a variant of the method of Frobenius, from Physics 200.) First you say that you’ll write psi as a product of some function h(x) and a Gaussian bell curve, psi(x) = h(x) G(x). (The variable x represents position, where x=0 is the center of the SHO.) This just allows you to rewrite the Schrödinger equation in terms of h rather than psi, which makes it look prettier. Then we solve the new Schrödinger equation for h. The idea for doing this comes from looking at what a solution to the SE does far away from the center: looking just at really big values of x make the SE very easy to solve, and we see that psi seems Gaussian out there, so we guess psi is a Gaussian times some other stuff. (There is no loss of generality in doing this, as it might turn out that h(x) = stuff/G(x).) It is a result, well known to those who know it well, that most functions can be written as an infinite sum of powers of x. That is, given almost any function whatsoever, we can write it as (b0) + (b1) x + (b2) x^2 + (b3) x^3 + … and so on, where b0, b1, b2, b3 … are just numbers that depend on the function you’re writing in this form. The advantage to doing this is that the Schrödinger equation (in this case) relates h(x), the rate at which h(x) changes, and the rate at which the rate of h(x) changes (the first and second derivatives of h(x), respectively), and it is very easy to compute the derivatives of powers of x. So we put this infinite sum in for h(x) in the SE, and compute the derivatives of it, and suddenly we not longer have a differential equation (which is hard): it’s turned into a regular equation (which is competitively easy). Because of the details of the SE, it turns our that this equation gives all of the even b’s in terms of b0 and all of the odd b’s in terms of b1. [The equation is: b(j+2) = b(j) (2 j + 1 - K)/( (j +1) (j + 2) ), for integer j, where K is the energy times half hbar omega.] The only other quantity in the equation is the energy of the solution. So, given an energy, this easy equation will tell you h(x) and then you know what psi(x) is (= h(x) G(x)). But once more we run into the question of psi being able to represent a real particle. Now, h(x) has, in general, infinitely many terms, so it’s sort of worrisome that it might give the impossible infinite probability answer. But, psi is actually h times a Gaussian, and Gaussians get small very quickly as x increases, so maybe G(x) makes psi(x) small enough so that that doesn’t happen. But it turns out you can see how the b’s are related to each other for large powers of x, which lets you see how h(x) behave at large x. When you do this, you seen that not only does h(x) give an infinite answer, it’s so big that even h(x) G(x) doesn’t work. Does this mean that there is no solution? There’s one clever way out: h(x) won’t be too large if all of the b’s beyond a certain number equal zero. Then h(x) would just be a finite sum of powers of x, and psi(x) = h(x) G(x) would be small enough. How could that happen? Well, looking at the equation, the b’s above b(j) would all be zero if 2j + 1 - K = 0; that is, if K = 2j +1. Since the j’s are just 2, 3, 4, 5, and so forth, we see that psi must have only certain distinct energies if it is to represent a real particle. Well, what are they? We know that K is just the energy times some constants, so we find that E-j = (j + 1/2) hbar omega = (j +1/2) e. The same answer we got before! And the psi(x) = h(x) G(x) answers turn out to be exactly the same as the A(psi-0) answers from before! Conclusion If I haven’t made things completely opaque, I hope you can see something of the excitement of two utterly different approaches to the same problem giving the same answer and a bit of the admiration for the cleverness that went into the two methods. I just think it’s really cool. There is a practical point to doing it both ways as well: the ladder method leads to a very neat trick that lets you easily calculate the famous uncertain relation between energy and momentum for different states, and it’s easier to actually calculate the higher energy wave functions with the formula from the brute force method. So that’s my attempt to explain why I like quantum mechanics. The process that I’ve attempted to explain makes me feel happy and excited. Did that make any sense? More to the point, did anyone actually read all of it? (The longest document I’ve produced since high school!?) (6 Comments |Comment on this)
Friday, March 5th, 2004
10:31 pm	U Chicago I've been accepted into the University of Chicago physics summer REU program, and it looks like I'll be spending ten weeks there doing some manner of research with a group. Rare excitement, this. Of the ten programs I applied to, Chicago was something like my second choice, so I'm very happy about this. I should know what I'll be doing in a couple of weeks. Just a bit disappointed that I didn't get my first choice, at SLAC. I'm delaying my acceptance of the Chicago position until the deadline on the (now faint) hope that they might take me there. In other news, I'm all a-quiver to be reading Hamlet. (4 Comments |Comment on this)
Friday, February 27th, 2004
7:58 pm	“On my honor as a physicist…” Is a phrase that has been repeating itself in my mind these past two or three days, as a scrap of song somehow without a tune. I imagine saying this clause (or its close kin, “as I am a physicist…”) while making some bold or controversial claim, as if swearing by my faith, troth, or status as a gentlemen. Then someone would ask, in disbelief or confusion, what I meant in swearing as a physicist, of all the absurdities!? I explain that physicists see things as they truly are, not as they hope or expect or wish; that physicists are the most prefect custodians of the truth, and other nonsense of this sort, and it is by my sacred charge as one of these that I do swear. (8 Comments |Comment on this)
Sunday, February 15th, 2004
9:41 am	Paper (Not-) Writing Back in high school, I think I had only a fairly mild dislike of writing papers. This has since grown to the point where I think writing papers is the most unpleasant thing I actually do. Our first paper for Shakespeare, an analysis of one speech, was due Friday at midnight, 3-5 pages, thankfully down from the 6-8 it said on the syllabus. I got it done, and it was acceptable, but I had barely started really working on it even at 5 pm that night, and it of course suffered as a consequence. I wasn’t doing anything the preceding nights instead of writing the paper, it’s just that I sit down to work on it and instead daydream and feel sorry for myself, getting maybe 10 minutes of work done for each hour I spend ostensibly working. It’s funny, the time I spend trying to write papers turns out to be when I do my deepest introspection and self-analysis, or, depending on how you look at it, my most angst-filled wallowing. If this led to any actual change in my behavior that caused the worrying, it wouldn’t be so bad, but what actually happens is that the deadline gets close enough that I actually start being productive and write the paper. Then, when it’s done (without time for any extensive editing, of course) I promptly forget about my problems and randomly (mindlessly?) surf the web for a while to unwind. Fortunately, I’m taking three math/physics classes and only one with writing, so this tortuous process will happen at most twice more this semester. Ah, angst. (7 Comments |Comment on this)
Saturday, February 7th, 2004
11:51 pm	Fantastically productive today. Long hours in the library were rewarded with completing 95% each of two (out of three) problem sets, two acts of Henry V, physics reading, and sundry errands. Error analysis makes me happy. Always in labs before, I would say things like “The difference between the experimental and theoretical values is 3%. That’s pretty good, so our experiment is consistent with the theory of ________.” Now we know how to actually calculate our uncertainties and compare values, so we can genuinely access our results. You might think it’s boring, but I see it as an integral part of any science. Therefore, I am made happy to get a good bit closer to being able to do (and evaluate) real science. (1 Comment |Comment on this)
Thursday, February 5th, 2004
11:03 pm	35. What was the most rewarding educational experience you have had in science and /or technology? Why? My most rewarding educational experience thus far has been working at the Reed nuclear research reactor. The most unique aspect of my training there is the integration of theoretical ideas and seeing how things actually work in practice. The chief example is the reactor itself. In class, we learn concepts such as the prompt negative temperature coefficient, a safety feature which decreases the reactivity of the core as power goes up. Then, when we operate, we see how we have to pull the control rods out farther to adjust for it and obtain a visceral sense of how it works to accompany our theoretical understanding. Having obtained my operator’s license after a year of training, I now help to teach this year’s group of trainees. It’s wonderful to me to be able to explain reactor physics or the workings of neutron detectors, to make clear the points that confused me when I was learning the subject and attempt to improve on past presentations. It is fantastic to be part of and contribute to a group that is centered around using, learning about, and exploring a nuclear research reactor. (Comment on this)
Wednesday, February 4th, 2004
5:58 pm	34. At this point in your education, what will your chosen profession be and why? My choice of profession at this point in my education is a research professorship in physics. I would choose physics research because I think it is the most likely to satisfy one of the primary driving forces in my life, the desire to find out how things work. I am naturally curious, and this curiosity manifests itself most strongly in wanting to know how the universe really works. The ideal for me is the discovery of a unified theory of physics. One theory that combines all we know of the nature of matter and energy, space and time—that fully describes the basic operation of the universe—seems to me to be the greatest and most magnificent intellectual goal to strive for. It would provide a solid foundation for chemistry, biology, and the rest of the sciences. Proving and explaining in detail how the universe is governed at the most fundamental level would be a great stride forward, with implications for philosophy and theology. Understanding such a theory would be the fulfillment of my desire to know how the world operates, and actually contributing to its development would be, for me, a glorious achievement. I am lucky to have the skill and enjoyment in mathematics and physics, and the drive and commitment, to bring this goal within my reach. (4 Comments |Comment on this)
Tuesday, February 3rd, 2004
7:09 pm	33. The unique experiences and cultural backgrounds of the participating students influence the quality of SULI. What do you think you would bring to the program? One interesting aspect of my cultural background is the contrasting nature of my high school and college. My high school was a Jesuit, Catholic, institution, while Reed College is a very liberal institution dominated by atheism. I have been exposed to and spoken at length with individuals from almost every section along the various continuums of religious thought. One of my chief joys is engaging in deep discussions on philosophical, religious, scientific, and political topics. It is a wonderful experience to discuss religion with someone whose conception of the world is dramatically opposed to mine, to explain Schrödinger’s cat to a philosophy major who asks questions I could never have thought of, or to share life experiences with people whose backgrounds are so different from mine that I couldn’t even have conceived of them. I was born and raised in an urban area of Detroit, Michigan, and am a member of a multi-racial family. (2 Comments |Comment on this)
12:02 am	32. What are your areas of interest and what type of research activities would you like to be involved in at the Lab? The general area I am most interested in is basic physics research. The discipline that holds the most attraction for me is particle physics. The investigation into the forces of the smallest scales, both theoretical and experimental, excites me. In addition, I think I would find almost any research project interesting just by the virtue of systematically examining and learning more about some phenomenon or object. Regarding the actual activities that the research could consist of, I think I would be equally at home in the experimental or theoretical arenas. I would prefer that my project not consist exclusively of computer programming, but I am not at all averse to programming as a component of my work. (Comment on this)
Sunday, February 1st, 2004
7:09 pm	Ah, the public journal, where one reveals one’s innermost soul (or so one claims), submitting it in writing for approval or rejection by others. Something like a… personal statement? 31. Discuss any special skills you would like to exercise or develop during your SULI appointment. I would be pleased to practice or acquire any of the skills employed at SLAC or BNL. On the purely mental side, I enjoy and excel at such things as figuring out how to devise a computer algorithm to do what you want efficiently, thinking about physics, solving mathematical problems, and most of all learning new techniques, concepts, and facts. On the laboratory and experimental side, I have acquired from physics labs and working at Reed’s reactor the skill for hands-on work and discovered its attraction. I want to try my hand at larger, more substantial projects than can be found working a problem set or doing a laboratory project. Bringing my skills in mathematics, problem solving, and experimentation to bear on a single endeavor would be a great experience. (2 Comments |Comment on this)
Thursday, January 29th, 2004
10:38 pm	Manual SCRAM So I was an instructor at the reactor last night, in a lab where the goal was to teach the trainees about the console. The console is where we control the reactor and get readings on power level and so forth. Four trainees and I were testing out the SCRAMs so they could learn about them. SCRAMs are when we cut power to the electromagnets holding the control rods, dropping them into the core and shutting down the reactor in under a second. Very important stuff, required by law. The most basic SCRAM is the manual: press a button and the rods drop. Yeah, it was broken. I was (attempting to) illustrate the difference between two kinds of manual SCRAM, so I press the button and it doesn’t work like it’s supposed to. I glance at the trainees. ‘Um, we’ll try that again.’ Raise the rods a bit and press and hold the button firmly. No such luck. ‘Well, you all see why this is bad, right? You know what it’s supposed to do?’ Nods, a bit wide-eyed: we knew the reactor was ghetto, but the manual SCRAM not working? Beyond the pale. At this point I’m cracking up; I think this is hilarious. The manual SCRAM is always there, it’s tech specs required, you press the button, the rods drop, those lights go off and that light goes on. How hard can it be? It not working is a joke, too horrible to be serious. I turn around to Rachel (former Reed student, associate director of the reactor) and try to inform her of this curious development, but can’t get it out. ‘Rachel, we broke the manual…’ and dissolve into laughter. She eventually gets the message, comes over and proceeds to take off the front plate of the console, reveling a crow’s nest of wire soldered onto various connectors in an array of about 90 metal stubs. Apparently they were fiddling around in there earlier in the day, trying to fix yet another problem. By and by they get four different copies of the wiring diagram, each of dubious authority, and try to figure out if something got disconnected, shorted out, or soldered to the wrong stub. All this is only so interesting, so I go into the other room to see if I might dispense some wisdom there. Among other things, a trainee and I discover that the electromagnets (we have spares lying around) get quite a strong grip with only 24 volts across them. Fun stuff. Occasionally I check in with the people working on the console. They’ve got all the panels open, looking at relays, connections, and bundles of dozens of unlabeled wires. They call nchaimov, our unofficial expert on all things electronic, another guy who was working on the console before, the director. Nothing doing. After more than an hour, things are wrapping up, and it’s still not working. Rachel eventually takes out a button, fiddles with it a bit (they include a plunger and some electronics), and puts it back. It wasn’t seated properly. Try the SCRAM now. It works. Oh. That was it. The button wasn’t in all the way. Eh, it works now. (2 Comments |Comment on this)