Theory
drorzel | March 25, 2010I did one sketchy update from Portland last Tuesday, but never wrote up my impressions of the rest of the March Meeting-- when I got back, I was buried in grading, and then trying to put together Monday's presentation. And, for reasons that will become apparent, I was unable to write anything up before I left Portland
Anyway, for those who care, here are my impressions from the rest of the meeting:
Tuesday
In the 8am session, I went to the polymer physics prize talk by Michael Rubinstein, which was a sort of career retrospective, talking about how he wandered into the disreputable field of…
drorzel | March 15, 2010I'm terrible about taking notes on conference talks, especially when I'm jet-lagged and was sleep deprived even before I got on the plane. I do jot down the occasional paper reference, though, so here are the things I wrote down, and the talks they were associated with. This should give you some vague idea of what the meeting was like on Monday.
From Joel Moore's talk on topological insulators, one of the Hot New Topics in condensed matter, a review in Nature.
From Phillip Treutlein's talk on optomechanics, a recent preprint on coupling atoms to mechanical oscillators.
From Nathaniel Brahms's…
drorzel | February 12, 2010There have been a bunch of stories recently talking about quantum effects at room temperature-- one, about coherent transport in photosynthesis , even escaped the science blogosphere. They've mostly said similar things, but Thursday's ArxivBlog entry had a particular description of a paper about entanglement effects that is worth unpacking:
Entanglement is a strange and fragile thing. Sneeze and it vanishes. The problem is that entanglement is destroyed by any interaction with the environment and these interactions are hard to prevent. So physicists have only ever been able to study and…
drorzel | January 31, 2010The Firedoglake Book Salon with Sean Carroll last night was a lot of fun. I was generally impressed with the level of the questions, and the tone of the discussion. We went through all of the questions I had typed out in advance (I type fairly slowly, and revise obsessively, so it's hard for me to do this stuff in real time), and got a decent range of questions from the audience.
The introductory post I wrote for the salon is more or less what I would put in a review post here:
ean Carroll's From Eternity to Here sets out to explain the nature of time, particularly what's known as the "arrow…
drorzel | January 28, 2010Last week's Seven Essential Elements of Quantum Physics post sparked a fair bit of discussion, though most of it was at the expert level, well above the level of the intended audience. such is life in the physics blogosphere.
I think it's worth a little time to unpack some of the disagreement, though, as it sheds a little light on the process of writing this sort of thing for a general audience, and the eternal conflict between broad explanation and "dumbing down." And, if nothing else, it lets me put off grading the exams from last night for a little while longer.
So, what's the issue? The…
drorzel | January 27, 2010Dennis Overbye is a terrific writer, but I have to say, I hate the way that he falls into the lazy shorthand of using "physics" to mean "theoretical particle physics" in this article about a recent conference built around debates about the state of particle physics. He's got lots of great quotes from Lisa Randall and Lawrence Krauss and others about how things are really bleak on the theory side, and these are barely tempered by enthusiasm from experimentalists.
So, yeah, theoretical particle physics may well appear to be in crisis. But, look, theoretical particle physics is always in crisis…
drorzel | January 9, 2010One of the few sad things about the recent American domination of physics (says the American physicist) is that new physical phenomena are now mostly given boring, prosaic American English names. Don't get me wrong, I like being able to pronounce and interpret new phenomena, but when the pre-WWII era of European dominance faded away, we lost those awesome German names. Like, for example, zitterbewegung, a word that just demands an exclamation point: Zitterbewegung!
The phenomenon it describes, ironically, comes out of work by the great English physicist and odd duck Paul Dirac. Dirac's…
drorzel | November 2, 2009One of my pet peeves about physics as perceived by the public and presented in the media is the way that everyone assumes that all physicists are theoretical particle physicists. Matt Springer points out another example of this, in this New Scientist article about the opening panel at the Quantum to Cosmos Festival. The panel asks the question "What keeps you up at night?" and as Matt explains in detail most of the answers are pretty far removed from the concerns of the majority of physicists.
But it's a good question even for low-energy experimentalists like myself, as it highlights the…
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 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 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…
drorzel | August 27, 2009I'm feeling slightly better, but still a little wobbly, so here's what may be the dorkiest Dorky Poll yet:
How do you like your quantum mechanics?(trends)
drorzel | July 31, 2009I had a bit of a discussion via Twitter with Eric Weinstein yesterday, starting with his statement:
Ed Witten has no Nobel Prize. Now tell me again how this era's physics just feels different because we are too close to it.
Basically, he appears to feel that Witten is sufficiently smart that he ought to have a Nobel. My feeling is that if you look at the list of Nobel laureates in physics, you won't find any theorists who won before their theory had experimental confirmation. It's not an official rule, but it seems to be well established practice.
My attempt at an analogy was the late John…
drorzel | July 30, 2009Yesterday, I posted a silly poll about optical physicists. Who are those people, and why should you care about them?
In inverse order of popularity:
Bringing up the rear in this race is John William Strutt, who, even more than Lord Kelvin in the thermodynamics poll, is hurt by the fact that people know him by his title, Lord Rayleigh. His notable achievements in optics include a formalization of the resolution limits for optical devices, and the phenomenon known as "Rayleigh Scattering," which is the short answer to the question "Why is the sky blue?" (The long answer requires a whole book.)…
drorzel | July 29, 2009So, yesterday featured a silly poll about underappreciated old-timey physicists. Who are these people, and why should you know about them?
Taking them in reverse order of the voting:
Rudolf Clausius is the originator of the infamous Second Law of Thermodynamics, which states that the entropy of any closed system will tend to increase. He was one of the most important figures in terms of systematizing the study of thermodynamics, pulling a lot of other people's work together, and showing how it all fit.
James Joule was a brewer as well as a physicist, making him a really good guy to know. He's…
drorzel | July 23, 2009I've had a few conversations with other small-college folks about how there ought to be some sort of group within DAMOP for people at small colleges, given how many of us there are who do AMO physics. Nothing has ever come of it, because nobody wants to take on the administrative hassle of organizing such a thing.
Fortunately for small-college theorists, they have some people who are more willing to step up, and have formed the Anacapa Society:
The Anacapa Society promotes research in all areas of theoretical and computational physics at primarily undergraduate institutions. The Society…