Physics
drorzel | September 27, 2006Since I found myself talking about particle physics yesterday, and since I find myself in the middle of a seasonal allergy flare-up that's sapping my bloggy motivation, I thought I would dust off and re-post some old articles about particle physics. These date back to 2003, but I think they still stand up reasonably well.
This is the first of four Classic Edition articles, covering the different types of particles making up matter in the universe.
A few days ago, I linked to a news story about this paper in Physical Review Letters describing the discovery of a new type of subatomic particle.…
drorzel | September 27, 2006The AIP news feed features a story about a paper suggesting that the universe is ellipsoidal. Or at least, that it was, back in the early days.
The work is based on the famous WMAP picture of the microwave background (and no, it's not because the picture is oblong):
As you know, Bob, the picture shows the distribution of temperature fluctuations in the early universe. These temperature correlations correspond to slight variations in the density of matter at that time, density fluctuations that eventually evolved into galaxies and galaxy clusters.
(Explanation after the cut.)
We can't…
drorzel | September 26, 2006I end up buying a lot of weird things for my lab-- really expensive sand, for example-- but the latest purchase was a little strange even by my usual standards:
The other day, on my way into work, I stopped by the store and bought a roll of parchment paper, for use in the lab. It actually makes perfect sense, though it'll require a little explanation, below the fold
The brass thing in the picture above is a length of 3" diameter pipe, which is intended for use as a holder for a magnetic field coil. The coil, one of a pair used to produce a magnetic trap for neutral atoms, will consist of…
drorzel | September 22, 2006I'm teaching our senior major seminar this term, which means that once a week, I'm giving hour-long talks on topics of interest to senior physics majors. This week's was "How to Pick and Apply to a Graduate School."
I've probably written this basic stuff up about three times already, but I'm too lazy to look for it, and this particular presentation was slightly different than anything I may have put on the web in the past. And I might as well wring another post out of the topic, while it's fresh in my mind...
There are several steps to the grad school application process, but the most…
drorzel | September 18, 2006Alternate title: Imminent Death of High-Tc Superconductivity Predicted. Film at 11.
PhysicsWeb has a story about a study of condensed matter papers that has been posted to the arxiv, predicting the imminent death of high-temperature superconductivity:
The new study was carried out by Andreas Barth from the FIZ Karlsruhe and Werner Marx from the Max Planck Institute for Solid-State Research in Stuttgart, who examined the number of papers listed in the INSPEC and Chemical Abstracts Service databases with words like "superconductivity" or "superconductor" used in the title or listed as "keywords…
drorzel | September 17, 2006So, the good news is, Gregg Easterbrook is writing about football for ESPN again. His "Tuesday Morning Quarterback" columns are some of the most entertaining football writing around. Here's hoping he can make it through the whole season without saying something stupid to get himself fired.
The bad news is, Gregg Easterbrook is writing about science for Slate. Actually, Gregg Easterbrook writing about anything other than football is bad news, but science is particularly bad. His knowledge of the subject always seems to operate at the Star Trek sort of level-- like he's read the glossary of a…
drorzel | September 14, 2006It's been a while since I did one of these, so here's a new Dorky Poll for readers to vote on: What's your favorite of the fundamental forces of nature?
As always, vote by leaving a comment. The winning force will be entitled to display a small graphic proclaiming it the choice of ScienceBlogs readers on all its exchange bosons.
The candidates (below the fold):
The Strong Nuclear Force: Binds quarks into nucleons, and nucleons into nuclei. Arguably the most difficult to deal with mathematically, as it gets stronger at long range. The Democratic Party of fundamental forces, because it just…
drorzel | September 14, 2006The current crop of String Theory Backlash books has a lot of people wondering about what will replace string theory as the top fad in theoretical physics. Other people (well, ok, me) are worried about a more important question: What will replace string theory as the most over-hyped area in theoretical physics?
Dave Bacon selflessly offers up his own field of quantum information, noting that Lee Smolin praises quantum computing theorists as "young" and "smart." As Dave notes, this is the physics equivalent of "hip" or "hot" in more general pop culture.
And Scott Aaronson offers further…
drorzel | September 14, 2006Over at Science and Reason, Charles Daney has launched a new blog carnival, focussing on physical science and technology issues. I rarely remember to participate in these things-- the deadlines just go whooshing by, like deadlines do-- but the general concept is pretty popular, and we need more physical science blogging on the Interweb. There are, what, nine different bio-themed blog carnivals? There should be at least one about physics...
And there's some good stuff in the first issue, now available: Philosophia Naturalis #1. So check it out, and if you have a better memory than I do, send…
drorzel | September 12, 2006The two most talked-about books in physics this year are probably a pair of anti-sting-theory books, Lee Smolin's The Trouble With Physics, and Peter Woit's Not Even Wrong, which shares a name with Jacques Distler's favorite weblog. I got review copies of both, but Not Even Wrong arrived first (thanks, Peter), and gets to be the first one reviewed.
Of course, I'm coming to the game kind of late, as lots of other high-profile physics bloggers have already posted their reviews, and various magazine reviews have been out for months. Peter has collected a bunch of links in various posts. I don't…
drorzel | September 8, 2006One of the things that ends up bothering me about the discussion of how to get more women in science is that it tends to focus on the college and professional elvel. Everybody seems to have an anecdote about a creepy physics professor, or an unpleasant graduate student, or a sexist post-doc.
This bugs me for a couple of reasons. The obvious one being that I'm a college physics professor, and I'm not that guy. I'm not fool enough to try to deny that unreconstructed sexist pigs exist in the profession, but I'm not one of them, and neither are my immediate colleagues, and sweeping statements…
drorzel | September 8, 2006One of the perks of this corporate blogging gig is that it's put me on the radar of book publishers, who have started sending me free stuff. We like free stuff, here at Chateau Steelypips, and we like books, so that's a Good Thing.
It's becoming almost too much of a Good Thing, though-- In the past week or so, I've received:
Not Even Wrong by Peter Woit (thank you, Peter), which I finished last night (review forthcoming).
The Republican War on Science by Chris Mooney, in the spiffy new paperback edition.
The Revenge of Gaia by James Lovelock (thrown in with tRWoS by the publisher).
The…
drorzel | September 7, 2006This is nearly a month old, now, because I keep saying "Oh, Idon't have time to do this justice-- I'll write about it tomorrow." I really need to stop doing that.
Anyway, Physics News Update has a story about a scheme to measure gravity using Bloch oscillations, based on a paper in Physical Review Letters. This is especially interesting to me, because the most important paper of my career made use of Bloch oscillations to get our experimental signal.
A quick explanation below the fold:
Bloch oscillations are a weird phenomenon you encounter in condensed matter physics. The easiest way to…
drorzel | September 7, 2006In email, David Rosenthal asks my opinion of a rant at globalresearch.ca about the stupidity of physicists:
Indeed, the modern professional physicist has usually subjected himself (less often herself) to extreme specialization, to be able to handle the technical side of the profession. This training is also largely about adopting the culture of the professional physicist: Examples and examples of what are "good problems - good questions" and what are "bad (= 'unmanageable') problems"; and examples and examples of how one tames a new problem and fits it into the mould of what a physicist can…
drorzel | September 5, 2006In the previous clock tutorial post, I described the basic workings of a cesium atomic clock, which looks sort of like this:
It works by sending a beam of cesium atoms through two microwave cavities. The first cavity synchronizes the "clock" in the atoms with the microwaves, and the second cavity checks whether the two are still in synch. If they are, the microwaves are at the right frequency; if they aren't, the frequency is corrected.
The key feature that determines the performance of this clock is the time between cavities. The longer the atoms spend in between the two, the better the…
drorzel | August 30, 2006In yesterday's post, I outlined the history of clocks starting from the essential feature of any clock, namely the "tick." I ended by saying that the best clock you can possibly make is one based off the basic laws of quantum physics, using the energy separation between two energy levels in an atom to determine a fixed frequency of light. In this case, the "tick" is the oscillation of the electromagnetic field-- whenever the electric field points "up," you count that as a "tick" of the clock. For light corresponding to the transition between the hyperfine ground states of cesium, those "ticks…
drorzel | August 29, 2006Over at A Blog Around the Clock, Bora put up a sixteen part series of posts talking about clocks. Unfortunately, he was talking about biological clocks, which are a specific and sort of messy application, from the standpoint of physics.
I talk a bit about clocks for our first-year seminar class, as a part of my two-week module on laser cooling (laser-cooled atomic clocks being one of the major applications). Like most of the other good bits of that module, this is shamelessly stolen from talks I've heard Bill Phillips give, but it works pretty well.
In order to really discuss the physics of…
drorzel | August 28, 2006Via a comment at Cocktail Party Physics, I have become aware of the existence of the "Physics Chicks" LiveJournal community. It's probably safe to assume that the Female Science Professor isn't wild about the name.
It's billed as "An online community for crazy and cool women in physics," or at least those crazy and cool women in physics with LiveJournal accounts. So, you know, there you go. Something for everyone out there on the Internets.
drorzel | August 25, 2006I've talked before about the tension between the desire to encourage students to major in physics and the tight job market in academia. Every time I talk about ways to draw more students into physics, it seems that somebody pops up to call me irresponsible for trying to lure them into a dead-end career track, saying that we don't really need more physics majors.
Eugene Wallingford quotes the best concise response to this argument that I've heard:Another colleague spoke eloquently of why we need to work hard to convince young people to enter the sciences at the university level. He said…
drorzel | August 24, 2006Gordon Watts reminds me that the start of a new academic year means more than just the arrivial of a new crop of freshmen. For grad students, it's qualifying exam season.
For those not in the know, "qualifying exams" are a common feature of most Ph.D. programs. These are big, comprehensive tests that all students have to take at the end of the required course work. They usually come at either the end of the first year, or the start of the second year, and you have to pass the test in order to continue in the program.
And, of course, the tests aren't exactly easy. As Gordon puts it:
The common…