Theory

In the reader request thread, Brad asks about superconductors: Why is a room temperature superconductor so hard? Why do things have to be cold for there to be no resistance (I can guess, but my knowledge of super conductors consists of the words "Cooper pairs" which does not get me very far.) Since next year will mark 100 years since the initial discovery of superconductivity in mercury by Heike Kammerlingh Onnes, this is a good topic to talk about. Unfortunately, it's a bit outside my field, but I can give you what I know from my not-much-better-than-layman's understanding of the field, and…
Yesterday's post about how nobody cares about condensed matter physics produced a surprising number of comments of the form "I was really hoping you would post about topological insulators," which surprised me a bit. Anyway, since people asked for it, I'll give it a shot. The important caveats here are that 1) this isn't my field, and 2) I have not read a great deal of the primary literature on this, so my understanding is not that deep. We'll do this in Q&A format, as that's been working well for ResearchBlogging posts lately. So, what's a "topological insulator," anyway? You make a…
With the rumors of a Higgs Boson detected at Fermilab now getting the sort of official denial that in politics would mean the rumors were about to be confirmed in spectacular fashion, it's looking like we'll have to wait a little while longer before the next "Holy Grail" of physics gets discovered. Strictly speaking, the only thing I recall being officially dubbed a "Holy Grail" that's been discovered was Bose-Einstein Condensation (BEC), first produced by eventual Nobelists Carl Wieman and Eric Cornell in 1995. Somebody, I think it was Keith Burnett of Oxford, was quoted in the media calling…
Next in line of questions from readers, we have tbell with: Since science is a self-correcting process (maybe only at a statistical level, not necessarily an individual level), it would be cool if you would relate the last time you were seriously wrong about some aspect of science or research, and how you altered your thinking as a consequence. This is kind of a tough one to answer, because I'm an experimentalist. Most of the mistakes I make in the process of research are problems of a technical nature, like "I totally thought that would work, but the impedance of the vacuum feed-throughs…
Tommaso Dorigo has an interesting post spinning off a description of the Hidden Dimensions program at the World Science Festival (don't bother with the comments to Tommaso's post, though). He quotes a bit in which Brian Greene and Shamit Kachru both admitted that they don't expect to see experimental evidence of extra dimensions in their lifetime, then cites a commenter saying "Why the f*** are you working on it, then?" Tommaso offers a semi-quantitative way to determine whether some long-term project is worth the risk, which is amusing. I was reminded of this when I looked at the Dennis…
The Science Channel debuted a new show last night, Through the Wormhole with Morgan Freeman, with the premier apparently designed by committee to piss off as many Internet types as possible. The overall theme was "Is there a creator?" and it featured physicist-turned-Anglican-priest John Polkinghorne talking about fine-tuning but no atheist rebuttal. It spent a good ten minutes on Garrett Lisi and his E8 theory, making it sound a whole lot more complete than it is. And it got this aggressively stupid review in the Times: Oh, let's face it: it was hard to concentrate on the first half of the…
Since I was going to be down here anyway to sign books at the World Science Festival Street Fair, Kate and I decided to catch one of the Saturday events at the Festival. It was hard to choose, but we opted for the program on Hidden Dimensions: Exploring Hyperspace (Live coverage was here, but the video is off), because it was a physics-based topic, and because I wrote a guest-blog post on the topic for them. (No, we didn't go to the controversial "Science and Faith" panel, opting instead to have a very nice Caribbean dinner at Negril Village, just around the corner. I'll take excellent…
This may be a job for the MythBusters, but I'll throw this out as a puzzle for interested blog readers. I don't know the answer to this (though it wouldn't be all that hard to determine experimentally), I just think it's sort of interesting. There's a poll at the bottom of this post, but it requires some set-up first. So, it's coming up on summer now, and I've been doing a bunch of errand-running this week, which means a lot of getting in and out of the car in sunny parking lots. Which raises the question: If you have an air-conditioned car, is it better to leave the car windows open a crack…
Since I sort of implied a series in the previous post, and I have no better ideas, here's a look at Thursday's DAMOP program: Thursday Morning, 8am (yes, they start having talks at 8am. It's a great trial.) Session J1 Novel Probes of Ultracold Atom Gases Chair: David Weiss, Pennsylvania State University Room: Imperial East Invited Speakers:  Cheng Chin,  Markus Greiner,  Kaden Hazzard,  Tin-Lun Ho  Session J2 Coherent Control with Optical Frequency Combs Chair: Linda Young, Argonne National Laboratory Room: Imperial Center Invited Speakers:  J. Ye,  Moshe Shapiro,  W. Campbell,  …
I was pretty sedentary on Wednesday, going to only two sessions, and staying for most of the talks in each. I spent most of the initial prize session getting my bearings in the conference areas, and talking to people I know from my NIST days. In the 10:30 block, I went to the session on Alkaline Earth Quantum Fluids and Quantum Computation. Tom Killian of Rice opened with a nice talk on work his group has done on trapping and Bose condensing several isotopes of strontium; somebody near me pooh-poohed it as just a technical talk on evaporative cooling issues, but I thought Tom did a nice job…
The conference I'm at this week is the annual meeting of the Division of Atomic, Molecular, and Optical Physics of the American Physical Society (which this year is joint with the Canadian version, the Division of Atomic and Molecular Physics and Photon Interactions, or "DAMPΦ." The Greek letter is a recent addition-- as recently as 2001, they were just DAMP.). As the name suggests, this is a meeting covering a wide range of topics, and in some ways is like two or three meetings running in parallel in the same space. You can see the different threads very clearly if you look at the different…
It's been a very long day, so I'm lying on the couch watching "Pardon the Interruption" on ESPN. They're having a boring conversation about baseball, and I'm just drifting off into a pleasant doze when: "Fear! Fire! Foes! Awake! Fear! Fire! Foes! Awake!" I jolt awake. "What are you barking at?!?" I yell at the dog, who is standing in the middle of the living room, baying at nothing. She stops. "Scary things!" The room is empty. "There's nothing here," I say, and then hear a car door slam. I look outside, and see the mathematician next door heading into his house. "Were you barking at Bill? He…
There's a Dennis Overbye article in the Times today with the Web headline "From Fermilab, a New Clue to Explain Human Existence?" which I like to think of as a back-handed tribute to the person who linked to an interview with Sean Carroll by calling him "The cosmologist, not the scientist." This is the secret of human existence explained by science, not biology. The physics issue in question is why we have more matter than antimatter in the universe, as symmetry would seem to demand they be created in equal amounts in the Big Bang. Had that happened, though, all of the matter should've…
Matt's Sunday Function this week is a weird one, a series that is only conditionally convergent: So the sum of the infinite series, by inexorable logic, is both ln(2) and ln(2)/2. How is this possible? Of course it isn't. The flaw in our logic is the assumption that the series has a definite sum - in the mathematical parlance, that it's absolutely convergent. This series is not, it's only conditionally convergent. In fact you can show (the great G.F.B. Riemann was the first) that with judicious rearrangement, you can get this series to converge to anything at all. As such it's only…
I get asked my opinion of Bohmian mechanics a fair bit, despite the fact that I know very little about it. This came up again recently, so I got some suggested reading from Matt Leifer, on the grounds that I ought to learn something about it if I'm going to keep being asked about it. One of his links led to the Bohmian Mechanics collaboration, where they helpfully provide a page of pre-prints that you can download. Among these was a link to the Bohmian Mechanics entry in the Stanford Encyclopedia of Philosophy, which seemed like a good place to start as it would be a) free, and b) aimed at a…
I've written before about the problem of having in-between views on controversial subjects in blogdom. This is something that also comes up in Jessica's excellent entry on online culture, and has been scientifically demonstrated in political contexts. I'm somewhat bemused, then, to see the same thing happen in a physics context. A while back, I got an email asking about quantum foundations that read in part: I'm very keen to understand why you and Andrew Thomas reject [the Many-Worlds Interpretation of QM]. I'd be very happy if you'd take a few minutes to try to describe why you think MWI is…
Over in Twitter-land, S. C. Kavassalis notes a Googler who's not afraid to ask the big questions: Weird Google search of the week: 'the "one" scientific idea that we need to believe'. Uh um, I'm sure my blog couldn't possibly answer that. It's a good question, though, ad there are a couple of different ways to take it. You could read it as "What one scientific idea is supported by the most experimental proof?" or you could read it as "What one idea is most central to science generally?" "The Standard Model" was quickly suggested on Twitter, which could fit either. I think it might be…
A sad and sordid story from the Times Higher Education following the rescinding of invitations to a conference on quantum foundations: Details of the conference in August for experts in quantum mechanics sounded idyllic. Participants were due to discuss "de Broglie-Bohm theory and beyond" in the Towler Institute, which is housed in a 16th-century monastery in the Tuscan Alps owned by Mike Towler, Royal Society research fellow at Cambridge University's Cavendish Laboratory. Last week, any veneer of serenity was shattered. Conference organiser Antony Valentini, research associate in the…
I wanted to test whether I can put links into PollDaddy poll items for the Laser Smackdown wrap-up tomorrow, so I needed a test poll. But, of course, if I'm going to go to the trouble, I might as well post it, so here's a dorky poll inspired by the fact that the book I'm using for Quantum Mechanics this term uses CGS units: What's your favorite system of units?online surveys It was inspired by a quantum book, but it's a classical Internet, so please choose only one. Or leave a comment to complain about the absence of your preferred choice.
The National Science Board made a deeply regrettable decision to omit questions on evolution and the Big Bang from the Science and Engineering Indicators report for 2010. As you might expect, this has stirred up some controversy. I wasn't surprised to learn this, as I had already noticed the omission a couple of months ago, when I updated the slides for my talk on public communication of science-- the figure showing survey data in the current talk doesn't include those questions, while the original version has them in there. I noticed it, and thought it was a little odd, but it had no effect…