Physics
drorzel | March 13, 2008As I mentioned a few days ago, I visited Luis Orozco's lab during our trip to DC last week. I already talked about his cavity QED stuff, but that's only one of the projects under development. He's also working on a next-generation apparatus for the laser cooling and trapping of francium, to be done at the TRIUMF accelerator in Vancouver-- francium is an element with no stable isotopes, and at most a few grams of it exist on the earth at any given moment. Luis and his students demonstrated the laser cooling of francium a few years back, using atoms made in an accelerator at Stony Brook out on…
pontiff | March 12, 2008I'm heading home from the March meeting, after giving my talk this morning and then having a nice lunch with graduate (and one undergraduate) students at a "Meet the Experts" lunch. Yeah, somehow I slipped by the guards! Luckily a real expert was there, in the form of Paul Kwiat, so all was good and the students didn't learn anything to disastrous. "What I learned at the March meeting" below the fold.
Things I've learned at the APS March meeting:
There are a lot of physicists. Even if you don't count the particle and nuclear and gravitational physicist who have their own meeting. Oh,…
drorzel | March 12, 2008One of the many very cool things going on in the Laser Cooling Empire at NIST is a series of experiments using optical tweezers to study various biological systems. I used to share an office with the biochemist in the group, who was there to handle the wet chemistry that physicists are notoriously bad at.
I've toyed with the idea of setting up an optical tweezers apparatus at Union-- the optical set-up is very simple-- so I spent a little while talking about it with Kris Helmerson, the PI on that project. He mentioned some cool things they were doing, one of which is explained very nicely in…
drorzel | March 12, 2008Via email, Reference Games, featuring two versions of the classic video game "Asteroids" (well, it's a classic if you're my age...). The cool wrinkle: light speed in the game is set to be very low, and you can toggle back and forth between the ship frame and the frame of the background stars, to see relativistic effects.
With or without length contraction, I'm still terrible at video games, but it's an amusing time-waster, and more plausibly work-related (for me) than playing poker on Facebook...
drorzel | March 11, 2008Another of the labs I visited while in DC was Steve Rolston's lab at the University of Maryland. This actually contains the apparatus I worked on as a graduate student, including many of the same quirky pieces of hardware-- Steve was the PI (Principal Investigator) for the metastable xenon lab in the Phillips group at NIST, and when he left NIST to take a faculty position at Maryland, he took the apparatus with him.
The xenon lab is now dedicated to work on ultracold plasma physics, which they were just starting when I graduated. The idea is that you can use laser cooling to accumulate a…
drorzel | March 11, 2008In the previous post on this topic, I discussed the various types of noisy vacuum pumps, both clean and dirty varieties. This time out, we'll deal with the quiet pumps, the ones that don't deafen people working in the lab.
Quiet and Dirty: The quintessential quiet and dirty pump is an oil diffusion pump. These have no moving parts, but operate by heating a low-vapor-pressure oil inside a series of baffles so that it sprays out in a downward jet. The oil jet will collide with air molecules in the way, and force them back into the reservoir region of the pump, where they can be pumped away by…
drorzel | March 11, 2008The annual March Meeting of the American Physical Society is happening this week in New Orleans. This is the biggest physics conference of the year, by far, with close to 7,000 attendees-- despite what you might think from the Internet, the Condensed Matter crowd who attend the March Meeting significantly outnumber particle physicists and high-energy theorists.
I don't usually go to the March Meeting-- it's just too damn big. I went to the Centennial Meeting in Atlanta in 1999 (and gave an invited talk, in fact), and didn't care for it all that much. I prefer DAMOP, which is much smaller-- a…
drorzel | March 10, 2008While Kate was off being all lawyerly at her NAAG workshop, I spent my time visiting my old group at NIST, and some colleagues at the University of Maryland. This wasn't just a matter of feeling like I ought to do something work-like while she was workshopping-- I genuinely enjoy touring other people's labs, and hearing about the cool things they're working on.
I figure that, having spent a day and a half talking about hot new physics experiments, I may as well mine them for blog fodder. I've managed to scrounge up papers related to a lot of the experiments in question on the arXiv, but the…
drorzel | March 10, 2008A great many physics experiments need to be conducted at low pressures, in order to avoid sample contamination, thermal effects, or dissipative forces produced by interaction with air. Some experiments don't require all that much in terms of vacuum, while others require pressures so low that they're limited by the diffusion of gasses through stainless steel.
To cover the wide range of pressures needed for different experiments, there are lots of different types of vacuum pumps, and there are nearly as many schemes for classifying them. As an experimental physicist and blogger, though, I've…
pontiff | March 9, 2008Hi ho, hi ho, it's off to the March Meeting I go. To run and play, and talk all day, hi ho, hi ho, hi ho, hi ho.
Talks I will most likely be attending: these. Food I will be seeking out this. Exciting physics works I will be on the outlook for: here
pontiff | March 7, 2008Hurray! My letter to Physics Today along with a delightful response from N. David Mermin has been published. I particularly enjoyed Mermin's closing line:
It may be quixotic (but certainly not Qxotic) to try to correct the spelling of an entire community, but I owe it my best shot. What else is retirement good for?
Sweet! Now I can check off from my list of things to do in life: "Get published in Physics Today over issues related to my literature degree."
pontiff | March 4, 2008Visiting Princeton, the American home to Albert Einstein, I'm reminded of one of my favorite "paradoxes" of special relativity. And, even more so, one of my favorite versions of this paradox which, when I first heard it, it blew my mind. What paradox is this of which I speak? The twin paradox of course! Really just the plain old twin paradox? No. Much better than that: the twin paradox in donut space!
The twin "paradox" of special relativity is really one of the classics of undergraduate physics. Two twins, born minutes apart, over the years drift apart. One becomes an astronaut and…
pontiff | March 2, 2008On the arxiv Friday:
arXiv:0802.4248
Title: Coexistence of qubit effects
Authors: Peter Stano, Daniel Reitzner, Teiko Heinosaari
Comments: A paper with identical title is being published on the arXiv simultaneously by Paul Busch and Heinz-Jurgen Schmidt. These authors solve the same problem independently with a different method.
and
arXiv:0802.4167
Title: Coexistence of qubit effects
Authors: Paul Busch, Heinz-Jürgen Schmidt
Comments: A paper with identical title is being published on the arXiv simultaneously by Teiko Heinosaari, Daniel Reitzner and Peter Stano. These authors solve the same…
drorzel | March 1, 2008As mentioned previously, I was invited to discuss physics and politics at one of the local fraternities earlier this week. Oddly, given the primacy of Greek organizations on campus, this is only the fourth time I've set foot inside a fraternity or sorority house in seven years. The previous occasions were times when I was doing housing inspections for the committee that handles those matters.
They've cleaned up the house since the other time I was there-- they used to be Φ Γ Δ, years ago, and then there was a brief interregnum when they were officially "Alpha Beta" (referred to as "oh, those…
drorzel | February 29, 2008I spent the bulk of yesterday afternoon doing vacuum system work, specifically working on the system to feed gas into the atomic beam source. My feelings about this can be inferred from the Facebook status message I set at the time: "Chad Orzel abhors a vacuum."
The apparatus I'm building uses laser cooling to decelerate an atomic beam of krypton atoms in a particular metastable state. This works brilliantly to slow metastable krypton atoms down, but the only atoms affected by the laser are krypton atoms-- everything else continues along unimpeded. As a result, the entire experiment needs to…
pontiff | February 26, 2008On the intertubes today I'm seeing a lot of references to "Electron filmed for the first time" (digg, msnbc, Live Science.) For a decent explanation that doesn't involve radically distorting quantum theory, I recommend this Physical Review Focus article (and, of course, nothing compares to the original PRL...although it must be said, as always, that four pages is not enough, damnit!) Note that, if I understand correctly, the movie "filmed" above is a movie in "momentum space" and, of course, we're not really talking about the observation of a single electron, but of the momentum…
drorzel | February 26, 2008The local fraternities and sororities hold occasional dinners/ discussions with faculty, to demonstrate that they're engaged with the intellectual life of the college. One of my students invited me to dinner at the Change in Kinetic Energy fraternity tomorrow night, and I agreed to do a discussion of physics and politics.
That's a vague topic, because I didn't have anything really definite in mind for it, other than that it seems better suited to a dinner and discussion than any of my regular presentations, which tend to be PowerPoint lectures. That doesn't really seem appropriate, so I…
drorzel | February 25, 2008Over at evolgen, RPM is wondering about the disciplinary distribution of bloggers:
I have an intuition, backed up by absolutely no evidence, that my particular area of interest (evolutionary genetics) has more faculty blogging about stuff related to their research than other fields. This is most likely the result of my interest in those blogs, and, hence, my increased awareness of them compared to blogs of faculty in other research areas.
[... list of half-a-dozen blogs...]
That's not a lot of blogs, but it's also not a huge field. How does that compare with faculty who blog in your research…
drorzel | February 22, 2008A reader writes in with a literary query:
I was asked to teach a 400-level course on Nanotechnology at my U. In addition to the usual technical content, I would like to include a critical view of how nanotechnology is portrayed in popular culture. So I am looking for suitable works that can be examined. Naturally, Stephenson's Diamond Age and Crichton's Prey come to mind. You know of other examples that would make for meaty discussion by a bunch of engineers? [...] I want to stress that most of the course will focus on technical content, so whatever work we pick has to have *some* basis…
drorzel | February 21, 2008Janet Stemwedel is blogging, as is her wont, about questions of ethical behavior in science. She had a post Monday giving advice on how to counter unethical behavior, which all seems pretty good to me.
Unfortunately, the people who read and comment on blogs about academic culture tend to start at "corrosively cynical," and get more misanthropic from there, so Janet has been deluged with negative commentary about how nothing she suggests will work. Feeling beleagured, she has issued a call for comments from senior scientists, asking for stories of how they deal with ethical issues:
I keep…