Physics
drorzel | October 4, 2007The Institute of Physics is the UK's main organization of physicists (sort of like the American Physical Society), and yesterday, they announced their awards for 2007. The full list of winners is only available as a Word file, for some odd reason, but it's a distinguished group.
The prizes are headed by the brand-new Isaac Newton medal, which was awarded to Anton Zeilinger of the University of Vienna for his pioneering work on the uses of quantum entanglement:
His achievements include the first demonstration of quantum communication based on the entanglement of photons in 1995, the first "…
drorzel | October 3, 2007This is more Bora's thing than mine, but I should note that the new open access journal PMC Physics A has published their first articles as freely available PDF's. They also have a video interview with the editor up on the site.
Of course, with titles like "Dilaton and off-shell (non-critical string) effects in Boltzmann equation for species abundances," I'm not likely to be reading (or understanding) this particular journal much. But that's OK, they have an AMO physics journal coming soon, and if you act quickly, they'll publish your paper for free (submit by December 1).
They also have the…
drorzel | October 2, 2007Speaking of cryptic particle physcis results, noted rumor-monger Tommaso Dorigo has a rather long post about the ongoing Higgs search. It basically boils down to "There are new results due to be released soon, and I'm not going to talk about them," which wouldn't seem to require 2000 words, but there you go.
Anyway, if you're anxiously following the search for the Higgs boson, he's hinting away about the upcoming update to the small signal that created a bit of a stir back in January. If there's anything to it, that would be really exciting, but for now, only people within CDF know, and they'…
purepedantry | October 2, 2007I had not thought that water was a poorly understood substance. Here are two interesting water articles that show that there is still more to learn. Who knew.
First, if you put water in a high DC current it can form a bridge between two beakers:
When exposed to a high-voltage electric field, water in two beakers climbs out of the beakers and crosses empty space to meet, forming the water bridge. The liquid bridge, hovering in space, appears to the human eye to defy gravity.
Upon investigating the phenomenon, the scientists found that water was being transported from one beaker to another…
drorzel | September 28, 2007Physics World had a news story about developments in quantum computation, covering two new papers in Nature:
Coupling superconducting qubits via a cavity bus from the groups of Steve Girvin and Rob Schoelkopf at Yale, also described in this press release.
Coherent quantum state storage and transfer between two phase qubits via a resonant cavity by a group at NIST at Boulder, also described in this press release.
These are completely independent experiments, as far as I know, but they're doing essentially the same thing: They're demonstrated the transfer of quantum information between two "…
drorzel | September 26, 2007So, I've put myself into a position where I need to spend a substantial amount of time thinking about weird foundational issues in quantum mechanics. This has revealed to me just why it is that not that many people spend a substantial amount of time thinking about weird foundational issues in quantum mechanics.
Let's consider a Mach-Zehnder interferometer, of the type shown in the figure at left (click the figure to see the original source). A photon (or an electron, or an atom, or any quantum particle) enters the interferometer at the lower left, and is split onto two paths by a 50-50…
drorzel | September 21, 2007It's job-hunting season in academia, which also means it's talking-about-the-job-market season. After writing the previous post, I noticed a post on the same topic by Steve Hsu, who was interviewed for a Chronicle of Higher Education article (temporary free link, look quickly!) about the lousy job market in science. Steve has most of the relevant bits in his post, including this graph about the job situation in physics:
Of course, being a contrary sort, I'd like to quibble a bit with the graph and its presentation in the article.
The article makes a point of noting that:
In physics nearly 70…
drorzel | September 21, 2007In the neverending debates about the current state of physics-- see, for example, Bee's thoughtful post about The trouble With Physics, you will frequently hear it said that the academic job market in physics sucks. But what, exactly, does that mean in quantitative terms?
It's job hunting season in academia now-- still a little early in the season, maybe, but most places that are looking to make a tenure-track hire are probably accepting applications already. So I did a little poking around the Physics Today job listings to see what the numbers look like. This is the central clearing house…
drorzel | September 20, 2007Let's say you have a mirror-- not some cheesey $2 makeup mirror, but a research-grade aluminum mirror-- and it has some crud on it, say a film of junk deposited during your Summer Institute for Hot MEtal Chemistry. Like, say, the mirror on the right in this picture:
How do you get that mirror clean?
Well, first, you assemble your tools:
You'll need the mirror, some lens tissue (special soft, lint-free paper), a hemostat (I prefer the curved-tip kind shown here, but you can use the straight ones, too), and some solvent (the bottle here is methanol, but you sometimes need to use acetone).
The…
drorzel | September 18, 2007A quick physics news update, on some stories that came out last week:
"Thundercloud "accelerator" fires gamma-ray beam:" A team of scientists in Japan has seen a 40-second burst of gamma rays from a thundercloud. This was presumably produced by electrons accelerated to extremely high velocities within the could coming to a sudden stop-- a process with the fabulous German name "bremsstrahlung." This was not associated with lightning, and indeed, one of the scientists quoted in the article says that lightning would be counterproductive, basically "shorting out" the multi-million-volt potential…
drorzel | September 17, 2007Sean Carroll takes a look at economics from the point of view of a physicist:
Economists have a certain way of looking at the world, in which (to simplify quite a bit) people act rationally to maximize their utility. That sort of talk pushes physicists' buttons, because maximizing functions is something we do all the time. I'm not deeply familiar with economics in any sense; everything I know about the subject comes from reading blogs. Any social science is much harder than physics, in the sense that constructing quantitative models that usefully describe the behavior of realistic systems is…
drorzel | September 14, 2007The particle physics community in the US has rolled out a new site promoting the Large Hadron Collider, because, you know, there was a danger that we might forget that it's there. As part of the site, they're featuring four new physics blogs, by Monica Dunford, Pam Klabbers, Steve Nahn, and blogosphere veteran Peter Steinberg.
They really need to work on getting a blog interface that doesn't suck, or at least an RSS feed, but this has the potential to be an interesting site. It's also the second time that the particle physics community has organized a blogging effort (the first was 2005's…
drorzel | September 10, 2007I'm checking a last few things and putting papers into an envelope when the dog wakes up from her nap. "Hey," she says, stretching, "What're you doing?"
"I'm getting ready to mail this," I say.
"What is it?"
"Several copies of a book contract that I just signed."
"It's a book about me, right?" she says, wagging her tail hopefully. "Because I'm the best."
"Well, sort of. It's a popular science book, based on our conversations about physics."
"That's a good idea, too."
"Well, some people obviously think so, because they're going to pay me to write it."
"How much are you getting?"
"Well..." I…
bergman | September 5, 2007Steinn reports that the NRC has made its recommendations for NASA's Beyond Einstein program. The winners appear to be LISA, a gravity wave observatory, and JDEM, a competition of dark energy focussed satellites. Steinn has lots of links to the various projects. The executive summary of the report is availabe here (pdf).
I know next to nothing about these things, but from afar it always seemed like LISA was one of those neat ideas that was never actually going to happen. The basic idea is to put three satellites in orbit around the sun and bounce lasers around to measure gravitational waves.…
bergman | August 26, 2007The title of this post is a famous question (posed, for example, by Joe Polchinski) which is modeled after an even more famous question by Ken Wilson, "What is Quantum Field Theory?". I certainly can't answer the first question, but Wilson's question now does have a widely agreed upon answer (which is sadly not well presented in a popular literature that continues to repeat old myths about regularization) which I will mention a bit later
What I would mainly like to do, however, is to answer the much easier question, "What is string perturbation theory?" But before getting to that, let's talk…
bergman | August 23, 2007As I mentioned earlier, I'm currently attending the Simons Workshop in Mathematics and Physics at Stony Brook University. The weather finally warmed up today, and we relocated to Smith Point Beach to hear Juan Maldacena tell us a bit about AdS/CFT and gluon scattering. If you're looking for a precis of the talk, I'm afraid I'm not going to give it a try, but I'll commend you to the paper if only so you can read about the beautiful wire frames.
This is actually the second workshop for me this summer. Before coming here, I had the opportunity to spend three weeks at the Aspen Center for Physics…
bergman | August 20, 2007Thanx to everyone for all the interesting questions in the previous thread. I apologize for not being able to answer every one of them. I just arrived at a workshop on Long Island, and I'm also feeling a bit under the weather. From what I've seen so far, I think I will do a post on what is perturbative string theory and what does it have to do with spacetime and gravity (maybe it will even lead into a post on what is background independence). Feel free to use this thread for more questions if you like.
oracknows | August 19, 2007The answer, apparently, is yes, but only for a very short time.
I guess the whole exploding heads thing when people are exposed to vacuum (Outland) or just the very low atmospheric pressure on Mars (Total Recall) is a bit of an exaggeration.
bergman | August 17, 2007First of all, I'd like to thank Chad for the keys to his internet-house for the next few weeks. If you're here, you know that one of the things Chad believes in (and is quite good at) is using his weblog for the exposition of science for the general public. While I don't think I can manage any funny dog stories, I'd like to try to follow his example. I have some ideas already planned (such as, god help me, a three part series on the multiverse), but I thought as an initial post here, I'd go straight to the public. What do you want to hear about? Is there some aspect of string theory, quantum…
drorzel | August 15, 2007Michael Nielsen, who's so smart it's like he's posting from tomorrow, offers a couple of provocative questions about the perception of a crisis in funding for basic science:
First, how much funding is enough for fundamental research? What criterion should be used to decide how much money is the right amount to spend on fundamental research?
Second, the human race spent a lot lot more on fundamental research in the second half of the twentieth century than it did in the first. It's hard to get a good handle on exactly how much, in part because it depends on what you mean by fundamental…