Physics
drorzel | September 27, 2009There has been a fair amount of discussion of Graham Farmelo's The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom-- Peter Woit reviewed it on his blog, the New York Times reviewed it a couple of Sundays ago, Barnes and Noble's online review did a piece on it, etc.. Nearly all of the press has been positive, and while it's taken me a while to work my way through the book, that's entirely a function of having a day job and a baby. The book itself is excellent, and kept me reading alter than I should've several times, which is not something I can say about a lot of biographies…
drorzel | September 25, 2009So, who are the people in yesterday's poll about theoretical physicists, and why should you know them?
Three of the four shared a Nobel Prize for developing quantum electrodynamics. In reverse order of voting:
Julian Schwinger was an American physicist who came up with a very formal, mathematically rigorous way of describing the behavior of electrons interacting with light. This turns out to be a hard problem, because any attempt to calculate an electron's energy by simple, straightforward means ends up giving an infinite answer. Schwinger helped "renormalize" the theory, getting rid of the…
drorzel | September 25, 2009We're working on moving SteelyKid from formula to milk (which isn't going all that well-- dairy seems to make her gassy). This has led me to switch over to cereal in the mornings, since we're buying milk anyway, which frees up the time otherwise spent waiting for the toaster.
Cereal-wise, I tend to alternate between Cheerios (which we also buy for SteelyKid) and Raisin Bran-- my parents never bought sugary breakfast cereal, so I never developed a taste for any of those things. Being the ridiculous geek that I am, I've noticed something about the relative amounts of milk and cereal I use for…
drorzel | September 24, 2009I'm nearly done with Graham Farmelo's biography of Dirac (honest), which discusses the major attempts to understand the behavior of electrons in quantum mechanics. this calls for a dorky poll:
Which theorist of the electron was the best?(poll)
Try not to base your selection on which of these historical physicists has the best biography written about them.
drorzel | September 24, 2009One of the photo caption contest winners, Nick O'Neill, has finished his galley proof, and posted an early review of How to Teach Physics to Your Dog:
Casual physics intro books are quite possibly the hardest subgenre of physics books to write. Textbooks and further upper-level reading have expectations both of what you already know and how quickly you should pick up new material. Generally, those who pour through these types of books will read and reread until they've figured things out, regardless of how well the text actually explains things. Casual intro books, on the other hand, exist…
rallain | September 23, 2009You know I like the Mythbusters, right? Well, I have been meaning to look at the shooting bullets in the air myth for quite some time. Now is that time. If you didn't catch that particular episode, the MythBusters wanted to see how dangerous it was to shoot a bullet straight up in the air.
I am not going to shoot any guns, or even drop bullets - that is for the MythBusters. What I will do instead is make a numerical calculation of the motion of a bullet shot into the air. Here is what Adam said about the bullets:
A .30-06 cartridge will go 10,000 feet high and take 58 seconds to come…
esiegel | September 23, 2009Long you live and high you fly
Smiles you'll give and tears you'll cry
All you touch and all you see
Is all your life will ever be. -Pink Floyd
In part I of this series, we talked about a number of different ways -- all using gravity -- to measure the amount of matter in galaxies, clusters of galaxies, and the entire Universe. We got the same measurement no matter which method we used, finding out that 25-30% of the total energy of the Universe is in some type of matter. But, only about 0.5% of the total energy is in stars, which means that nearly all of this matter doesn't give off light! So…
drorzel | September 22, 2009The scheduled release of How to Teach Physics to Your Dog is three months from today. This is, as you most likely know, a book based on the frequent conversations Emmy and I have about physics:
To mark the pre-anniversary, Emmy has decided to use social media to showcase her physics knowledge: She's answering physics questions on Twitter. Post a question, tag it #dogphysics, and she'll answer it there. If you've got a philosophical objection to Twitter, you can leave a comment here, and get your answer via the Twitter link above.
So, if you've got a question about physics that you've been…
pontiff | September 22, 2009Two conferences. Renato Renner sends along a note about QIP 2010. The paper submission deadline is one month away:
QIP 2010 will be held in Zurich, Switzerland, January 18-22.
The submission deadline for contributed talks is 22 October 2009.
For more information, please see http://www.qip2010.ethz.ch
We look forward to welcoming you to Zurich,
the organizers
Also a conference on superconducting qubits in San Diego:
Please note our conference coming next spring; Coherence in Superconducting Qubits, to be held April 25-28, 2010, in San Diego, CA.
The agenda and registration are described at…
drorzel | September 22, 2009Buried in the weekend links dump at the arxiv blog was Scalable ion traps for quantum information processing:
We report on the design, fabrication, and preliminary testing of a 150 zone array built in a `surface-electrode' geometry microfabricated on a single substrate. We demonstrate transport of atomic ions between legs of a `Y'-type junction and measure the in-situ heating rates for the ions. The trap design demonstrates use of a basic component design library that can be quickly assembled to form structures optimized for a particular experiment.
At first glance, this isn't a sexy paper…
drorzel | September 21, 2009I'm halfway through Graham Farmelo's Dirac biography at the moment, and enjoying it quite a bit. Farmelo cites Dirac as one of the first physicists to evaluate theories on their mathematical beauty, rather than waiting for experiments. This is in stark contrast to his Cambridge colleague Rutherford, who was highly skeptical of abstract theory, and preferred to deal in concrete experiments.
This is one of the great chicken-and-egg problems in science: Should data come before theory, or should theory come before data? Thus, this seems like a good topic for a poll:
How do you like your science…
esiegel | September 18, 2009Before you ask yourself, "what kind of incendiary title is that," let me put this in perspective. In 2001, I started graduate school at the University of Florida, and in 2002, I took one of the most difficult year-long courses a physics student can take: Quantum Field Theory. This was both the best and worst course I've ever taken. I worked harder for it than I ever have for any other course, I learned more for doing it than I had at any other time, it was the most difficult time I've ever had in a course, and it was superbly taught by one Richard Woodard. Quantum field theory is possibly the…
drorzel | September 18, 2009Over at Jim Henley's place, Thoreau further justifies his status as an essential academic-physics blogger with a really good post about the problem of introductory labs:
In freshman labs, generally you’re trying to measure something (at least as it’s done at many schools). The measurement is never as clean as the stuff being taught in lecture (or interactive discussion-based peer-involved blah blah whatever). There is nothing wrong with the fact that lab measurements are not as clean as the stuff in lecture! However, it does mean that you aren’t spending those 3 hours thinking about the…
drorzel | September 18, 2009I'm teaching Quantum Optics again this term, talking about the interaction between light and matter in circumstances where you need to account for the quantum nature of one or both of those. We're starting on the actual interactions today, albeit with a semi-classical approach (Einstein coefficients and the Fermi Golden Rule), but we've just finished a whirlwind review of quantum mechanics, including a rapid survey of the different effects that determine atomic energy levels, and some of the ways we have to move those around.
This suggests a really dorky idea for a poll, so:
What's your…
rallain | September 17, 2009This is Tom's fault (Swans on Tea). He suspects that most of the physics blogs are read by physics bloggers.
I have kind of been avoiding this, but I guess I need to know who my readers are. Actually, there are two groups of readers - regular readers and googlers. So, who are you?
Loading...If you are a blogger, maybe you could list your blog in the comments. I will post the results after some time (or live if I figure that out).
Responses so far
I don't know how to make this live, so I will just update it every once and a while.
Here is a list of what was submitted as "other" (at this…
rallain | September 17, 2009Yes, this can be very complicated. But what should a middle-school student understand about light? You see stuff in textbooks that is either wrong or just a bunch of disconnected factoids (I like the word factoid). So, what do I think is important about light (not at the Maxwell's equations level)
What is a wave
If you want to talk about light, you need to talk about waves. So what is a wave? I like to start with an example. Suppose you are in a sports stadium - maybe a football game. Some inspired fan decides to start a wave. If you look at the individual people, the wave might be…
pontiff | September 17, 2009Get your daily dose of physics geekery--an interview with LHC director-general Rolf-Dieter Heuer--
I need to learn to use "symmetry breaking" in my everyday speech.
pontiff | September 16, 2009Via Asymptotia, an interview with Murray Gell-Mann (who just turned 80. Happy Birthday Murray!) I particularly like the comments at the end of the article:
Battles of new ideas against conventional wisdom are common in science, aren't they?
It's very interesting how these certain negative principles get embedded in science sometimes. Most challenges to scientific orthodoxy are wrong. A lot of them are crank. But it happens from time to time that a challenge to scientific orthodoxy is actually right. And the people who make that challenge face a terrible situation. Getting heard, getting…
rallain | September 15, 2009As I said before, I went a SPIN-UP workshop (you can find tons of info and the SPIN-UP report here). The basic idea of the SPIN-UP program is to first look at schools that are successful in their production of undergraduate physics majors. And with an understanding of what makes them successful, help other institutions become successful. Maybe you couldn't make it to the meeting, so here are some highlights. Oh. I believe that this highlights have very general applications. Although this is aimed at undergraduate physics, it seems it would apply to many other majors and maybe even to…
drorzel | September 15, 2009In reading a theoretical paper on electric dipole moments (well, OK, skimming through it looking for numbers), I ran across several Feynman diagrams with an "X" on one of the particle arrows. The caption contains the presumably-intended-to-be-helpful note "The cross denotes a mass insertion."
I have no idea what that means, and neither does the local person I ask to help me interpret such things. None of the undergrad-level nuclear/ particle texts we looked at contained an explanation, either.
This almost certainly means that it is some subtle technical point that is vastly beyond the level…