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Uncertain Principles

Physics, Politics, Pop Culture

Saturday, October 09, 2004

Is It Over Yet?

Oh, what I wouldn't give to live in FafWorld...

The two candidates' styles in the innovative town hall format are very different. John Kerry handles himself by amblin around stage in a folksy manner to win the confidence of his audience. At one point he builds a barn, which prompts the audience's lone Amish member to comment "Good work, English." George Bush tends to assert his strength in the debate by jumpin up behind John Kerry, clubbing audience members over the head with a wrench, an by launching himself out of a cannon wearin a unitard emblazoned with the logo "The Mighty Thor."

Giblets, take me away...

Posted at 9:46 AM | link | follow-ups | no comments

Thursday, October 07, 2004

Big Media Me, continued

No ego post about being on tv is really complete without a whopping huge grainy QuickTime movie. So, y'know, there you go.

Posted at 5:28 PM | link | follow-ups | 2 comments

Journal Club 1

A handful of papers that caught my eye from very recent journals:

Physical Review A (the September issue) throws up two articles that interest me. The first is a long article on Sub-shot-noise-limited measurements with Bose-Einstein condensates", by a couple of guys I know at Oxford. This is a theoretical treatment of something very closely related to work I did while I was at Yale (which, to the best of my knowledge, still hasn't seen print...).

The idea is to take a Bose-Einstein condensate (BEC), and split it into two parts, then let the two parts interfere with each other. By looking at the interference pattern, you can make a measurement of anything that changes the effective "path length" followed by the two interfering bits.

This is nothing especially new-- light interferometry is used to measure all sorts of things, and the same idea has been used with atoms by a number of groups. The trick here is that you divide the atoms in a way that produces a "squeezed state," which has a lower uncertainty in the number of atoms in each blob than you would expect from the Uncertainty Principle (at the cost of a higher uncertainty in a different property-- this uses the third uncertainty relation over in the links bar). Using such a state, you can make a more precise measurement than is normally allowed with a given number of interfering atoms.

This paper describes a simple scheme for realizing such a measurement with a condensate that's split into two parts. The two-site "lattice" case is a relatively easy problem to solve, but not the easiest thing to do experimentally. Leading to this beauty of a statement:

Multisite measurement schemes have the added advantages that number squeezed arrays of condensates have already been created in the laboratory (citation of me and some Germans). This is an interesting prospect that we shall explore in future work.

Having spent a few months working on the multi-site theory, let me take this opportunity to say: Have fun with that, guys. It's a real treat.

The second PRA paper that caught my eye is a "Rapid Communication" (usually meaning it was submitted to PRL, and didn't make the cut): Controlled many-body interactions in a frozen Rydberg gas. It, too, is loosely related to stuff that I did in a previous job.

The experiment here involves exciting a bunch of ultra-cold atoms to extremely high-energy excited states (called "Rydberg states"). If you go high enough, the atoms will ionize, and the sample turns into a plasma (this is the area I've worked with, a tiny bit), but if you stay below the ionization threshold, you still see some neat effects.

In particular, you see some phenomena that look like the result of collisions between atoms, even though the atoms are so cold that they don't move far enough during the experiment for a traditional collision to take place (hence "frozen"). This happens because Rydberg atoms interact at very long ranges (relatively-- the atoms are a few microns apart).

This is a fairly technical paper, which clears up the small amount of ambiguity about the source of the effect, by introducing a third Rydberg state (the effect in question involves atoms in two different state), and showing that it produces the expected behavior. It's nothing terribly surprising, but I think it's a neat sub-field, and I try to keep track of new developments.

There were also two papers in Physical Review Letters that I thought were worth a second look. One of them, Determination of the Number of Atoms Trapped in an Optical Cavity is a little surprising to me. Not because of the results, but because I'm not sure why it rates publication in PRL-- it's cool stuff, but not quite taht cool.

As you might expect, the paper deals with the trapping of atoms in an optical cavity. "Cavity" here means "two high-quality mirrors 42.2 microns apart," and it's an interesting problem because putting atoms into such a cavity will dramatically change the way they interact with light. "Cavity QED" is a fascinating regime, where you need to take into acount the quantum nature of both the atoms and the light field itself.

This specific paper strikes me as a fairly technical piece of work, though, which describes a way to monitor the number of atoms held in the cavity by looking at the light that leaks out. I'm not as up-to-date on the field as I might be, but this doesn't strike me as particularly surprising. It's very useful to anyone who wants to do cavity QED experiments involving small numbers of atoms, and it's an impressive experimental achievement (as all of Jeff Kimble's experiments are), but it doesn't seem like a PRL to me. But I could be missing something.

The final paper I want to note is Observation of Feshbach Resonances between Two Different Atomic Species, by the Ketterle group at MIT. "Feshbach resonances" is a quantum phenomenon that allows you to change the nature of the interactions between atoms in a BEC by applying an external magnetic field. This is a hot topic these days, because you can use these resonances to flip from repulsive interactions between atoms (where colliding atoms push each other apart) to attractive interactions (where they want to stick together and form molecules).

Feshbach resonances have been seen between atoms of the same type (two sodium atoms, two lithium atoms, two rubidium atoms), but this paper describes a Feshbach resonance between one lithium atom and one sodium atom. They set this up by putting a sodium BEC on top of an ultra-cold sample of lithium (not a ondensate), applying a magnetic field, and looking for a field value where atoms disappear from both samples (either because they form molecules, or because they get knocked out of the trap by a third atom). People have been playing around with making homonuclear molecules (Li2, Na2) from BEC's for a while now, and this work is a first step in the direction of making heteronuclear molecules (LiNa), which can be used for all sorts of different experiments.

Like anything from the Ketterle empire, it's a comprehensive and comprehensible paper, extending the BEC field into a new level of complexity. I don't want to think about how many fiddly little things have to work right to make this experiment work-- these guys are an impressive operation.

Posted at 11:05 AM | link | follow-ups | 5 comments

The First Rule of Journal Club Is: You Must Talk About Journal Club

One of my colleagues, an astronomer, has revived the on-again, off-again Astronomy Journal Club locally. For those not familiar with the phenomenon, a "Journal Club" is a regular meeting of people to talk about interesting papers published in research journals. Each time out, one person makes a short presentation about recent stuff. The exact format varies (I've seen it done with the specific papers announced in advance and distributed to the whole group, and also the "here's a list of recent stuff that I found interesting" thing that they're doing here).

This reminded me of one of the things I miss about being in a more research-focussed place. In my previous jobs, I used to spend every Monday morning scanning over the journals published that week, and picking out a handful of recent articles that caught my interest. Since becoming a faculty member, my mornings tend to be taken up with responding to student emails, reading announcements of the infinite number of faculty meetings held each week, entering grades into Excel, tweaking PowerPoint slides, trying to find demo equipment before class, trying to get said demo equipment to work, and a host of other things. I've really gotten out of the habit of reading current journals, and on some level, I miss that.

For a variety of reasons, I don't think a physics equivalent of the astronomy journal club would take off here, but I like the idea. In an effort to give myself some sort of incentive to get caught back up on the current state of research, I'm going to start posting short lists of interesting recent articles on this blog. These will be papers that catch my eye, for one reason or another, as I look through my usual set of journals: Physical Review Letters, Science, Nature, and Physical Review A, when it comes out. They'll be sort of slanted toward atomic, molecular, and optical physics, because that's what I do, but I may comment on papers from other fields, if I feel like it.

Of course, this does create a certain conflict with my original intention for this blog, specifically in that I've (privately) committed myself to providing science explanations that are comprehensible to the laity-- no "it's an SU(3) doublet" or "you just do a Wick rotation" pseudo-explanations allowed. That's not really going to be possible here, at least not to the extent that I like. Many of these papers will require so much background information to explain in detail that there's just no way to do it concisely. Some of the missing background is stuff that I do mean to explain, one of these days-- I've been struggling to come up with a really good BEC post for a while now-- but much of it will stay missing.

The compromise I'm going to make with myself is this: I will do the best that I can to boil each paper I mention down to a couple of sentences at the lie-to-children level, and give a short explanation of why I that paper was interesting to me. The technical details are probably only interesting to a half-dozen readers of this blog, so I'll mostly leave them out. When it can't be avoided, I'm going to try not to feel guilty.

So, there's the manifesto for this set of posts. I'm going to try to do this weekly, but I'm not going to go so far as to commit to a day of the week-- sometimes, it'll be early, sometimes late. And we'll see how long I can keep this up...

Posted at 10:37 AM | link | follow-ups | 6 comments

Wednesday, October 06, 2004

Big Media Me

My "How to Lie with Statistics" lecture was yesterday afternoon. I was splitting a class with a colleague (45 minutes each, give or take), and we showed up a bit early to get the computer stuff set up.

While we're fiddling with PowerPoint, a woman from the Communications office comes in, and asks "Are the tv people here yet?"

"Um. What tv people?"

It turns out that the local NBC affiliate had heard about the class in general (which gets a few sentences in this story), and thought it would make a nice lead-in to the debates for the six o'clock news. One reporter and one cameraman showed up to class, and videotaped part of the class, interviewed a few students, and got some sound bites from me. (I was amused to be asked "Can we get a couple of sound bites from you?" I guess it counts as refreshingly honest...)

The story was maybe four or five minutes long, and led off the six o'clock news. They had a clip of me quoting Disraeli, some miscellaneous shots of me pacing and talking with my hands (with voiceover saying "Professor Chad Orzel can make a lecture about how numbers are used to deceive entertaining," or words to that effect), and a sound bite about the wonderful other topics covered in the course. There are also a bunch of reaction shots of students, a couple of clips of my colleague talking about nuclear policy (sadly, they mispronounced her name), a gratuitous campus shot (it's really a very pretty campus), and three student interviews.

There were a couple of things that I'm not wild about-- the intro noted that "not all of the students are political science majors, and the professors were astrophysicists" in an amazed tone, and I wasn't really looking at the camera during the sound bite (being on tv is hard, hard work...)-- but it was a kick to see myself on tv. And not looking like a total dork was nice, too-- I was even pretty happy with how I sounded, which is rare, as my recorded voice often sounds awful to me.

As for the class itself, it went very well, I thought. I'll admit to hamming it up a little, but I got through everything I wanted to cover, and I didn't notice anybody walking out early, so that was good. They laughed in all the right places, and none of the wrong ones, and I think the survey results were effective. I found some good campaign-related examples on, and I was fairly balanced overall. For those who care (and have a fast connection-- the files are huge), my lecture slides are here (ppt format) or here (one-page web archive, if you can make it work).

It's definitely a weird feeling teaching a class that large, though. I've given a research talk to an audience that size before, but never an academic lecture. It was fun to do once, but I'm glad I don't teach at a place where I have to do that on a regular basis.

Posted at 7:41 AM | link | follow-ups | 1 comment

Tuesday, October 05, 2004

Slicin' Up Eyeballs, I Want You to Know

Watching the six o'clock news this evening (for reasons that will become clear tomorrow), they showed a clip of John Edwards, as a teaser for this evening's festivities. Since then, I've had the horrible image of him screaming "I wanna grow... grow up to be... be a debater!", with Kim Deal singing "dee- bate- errr" in the background.

Since I can't shake it, I'll share it. Misery loves company.

Posted at 9:10 PM | link | follow-ups | 5 comments

Dynamite Money

The Nobel Prize in Physics was announced today:

Americans David J. Gross, H. David Politzer and Frank Wilczeck won the 2004 Nobel Prize in physics on Tuesday for their exploration of the force that binds particles inside the atomic nucleus.

This is not an area of physics that I know much about, but what little I do know is pretty cool. The Post mentions one nifty aspect:

The three physicists came by their discovery through a brilliant and non-intuitive insight. They showed that unlike forces such as electromagnetism and gravity, which grow stronger as two particles get closer to one another, the strong force actually gets weaker as two quarks converge. It is as if the particles were connected by a rubber band that pulls them together more tightly as it stretches.

(I would've reversed the description, though. Saying that the strong force gets stronger as the particles get farther apart strikes me as more obviously counterintuitive than the reverse, and counterintuitive is what you want to emphasize. But then, what do I know...)

The strong force is deeply weird, and it's always faintly amazing to me that people succeed in doing anything at all with it. I don't know enough about the field to comment on the specific people getting the prize, but on a broader scale, this seems well-deserved.

I may try to come up with more coherent comments later, but my "How to Lie with Statistics" lecture is this afternoon, so I've got stuff to do.

Posted at 7:15 AM | link | follow-ups | 4 comments

Monday, October 04, 2004

Ask the Right Questions

Josh Marshall is all over the story of Fox's fabricated Kerry quotes, and offers some follow-up questions for Fox News. Calpundit Monthly has a question as well. The problem is, neither of them is asking the right questions.

The right question to be asking is "When will Carl Cameron start spending more time with his family?" It should be asked loudly and publicly, every time a Fox "News" representative pokes his head out of his hole. This guy should be sacked, and liberals should be demanding that he be sacked, as opposed to just snickering quietly in schadenfreude.

Or, put another way, Josh comes close to the right question:

If CNN's John King posted a story on the CNN website with fabricated quotes that had the president joking about funneling money to Halliburton or telling a crowd how only saps went to Vietnam, what would the fall-out or consequences be?

But fails to take it as a prescription. Ask yourself what the various right-wing hacks of the "blogosphere" would be doing, were this a quote by a CNN, CBS, or New York Times reporter, and then do that to Fox.

Yes, I know, the situation is a little different, given that CNN is actually trying to be a news organization, while Fox is only pretending. It seems sort of pointless to harass them about their ridiculous partisanship when that's really the whole point of the network.

Here's the thing, though: the people who watch Fox don't think that they're hacks. They think it's a real network. And here you have a golden opportunity to show them the truth-- scream and yell and raise a fuss until Fox clearly and publicly (and I'm not talking about a little website retraction notice, here) admits to wrongdoing, and fires those responsible. Until even the reddest of "Red State" voters has to admit that, yes, Fox did a bad, bad thing.

Don't let this pass by. Fight fire with fire. Embrace the power of the Shrill Side.

Aaaiii! Ph'nglui mglw'nafh Krugman R'lyeh wagn'nagl fhtagn! Aaaiii!

Posted at 7:47 AM | link | follow-ups | 11 comments

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