Physics
drorzel | April 22, 2008Two weeks ago, now, I promised some peer=reviewed physics blogging, to compensate for the "screechy monkey" nonsense. Of course, I got distracted by other things, but I've been sitting on this paper for a while now, and I really need to get it off my desk.
The paper in question is "Quantum Register Based on Individual Electronic and Nuclear Spin Qubits in Diamond," by the group of Misha Lukin at Harvard, published in Science last June. It's a clever idea for a way to do quantum computing using individual nuclear spins in a diamond matrix. I really like this idea, not least because it has the…
drorzel | April 21, 2008There's a new "Ask a ScienceBlogger" question out:
"A question from a friend's 9-year old son:
What is in the air we breathe? What is it's chemical composition?"
The short answer to this is "a little bit of everything." Pretty much
any substance we have on Earth can be found in the atmosphere
somewhere. The atmosphere is a pretty big place-- roughly
1044 molecules worth of stuff (that's
100,000,000,000,000,000,000,000,000,000,000,000,000,000,000, give or
take). In a collection that big, you'll find just about anything you
want.
All we can really do when asked about the composition of the…
esiegel | April 19, 2008Sometimes, gravity and motion has the power to mesmerize me. I found this online game called "compulse" which was so much fun, that I spent about 90 minutes this week just playing this game until I had beaten every level on the "pro" setting. Yikes. (My score is 104 under par, 8 under pro.)
And so, in the interest of bringing it to you, I've tried to embed it into my website. Have fun playing if it works in your browser (I told you to use firefox or safari), and if you enjoy playing with the mechanics of motion as much as I do, maybe you, too, have the interest it takes to be a physicist!…
drorzel | April 18, 2008(Because nothing brings in readers like a physics pedagogy post...)
Out in Minnesota, Arjendu is expressing high-level confusion about the business of lecturing:
As I've said a few times before in this blog, I prefer to let students read the text to get a preliminary take on physics content on their own, generate questions and confusions on which I focus during 'lecture', and then check their comprehension of these principles by working together on applying them via problem-solving -- and doing this in my presence so I can help them work out what they do and don't know.
I see this as…
scientificactivist | April 17, 2008When someone asks the question "why are veins blue?" a likely response is that they're blue because the blood in veins is deoxygenated. While it's true that venous blood vessels carry a lower concentration of oxygen than their arterial counterparts, this isn't the reason for their blue appearance in your skin. Still, when someone invariably responds to the veins-are-blue-because-they're-deoxygenated argument with the observation that "I've never seen blue blood before" one might then hear the slightly more sophisticated-sounding but increasingly far-fetched claim that we don't ever observe…
pontiff | April 15, 2008It was an unassuming blue-grey volume tucked away in the popular science section of the Siskiyou County Library. "Spacetime Physics" it announced proudly in gold letters across the front of the book. Published in 1965, the book looked as if it hadn't been touched in the decades since 1965. A quick opening of the book revealed diagrams of dogs floating beside rocket ships, infinite cubic lattices, and buses orbiting the Earth, all interspaced with a mathematical equations containing symbols the likes of which I'd never seen before. What was this strange book, and what, exactly, did those…
pontiff | April 15, 2008For those interested in accessing the arXiv on your iPhone, here is a web based iPhone page:http://arxiv.mobi. Sweet! This has been on my list of things to do, and now I can cross it off without having to do it myself!
pontiff | April 14, 2008I just learned the very sad news that John A. Wheeler has passed away. Wheeler was one of my heroes and inspired me in many ways to be where I am today. I'm buried under a heap of work today, but will write more when I can come up for air. Below I've pasted a post from my old blog describing a result I first learned about by reading a Wheeler paper.
Note: This post originally appeared at my old blog site.
When I was an undergraduate at Caltech visiting Harvard for the summer I stumbled upon Volume 21 of the International Journal of Theoretical Physics (1982). What was special about this…
drorzel | April 14, 2008Going off to a rugby alumni weekend generally requires entering a 48-hour news blackout, at least for me. Of course, the outside world doesn't stop just because I'm enjoying myself, so I emerge from my fog this morning to find that John Archibald Wheeler passed away. The New York Times obit is here, and Daniel Holz at Cosmic Variance offers a personal tribute, and I'm sure you'll see more.
(This is not, by the way, the first time that a notable public figure has died while I was in Williamstown carousing-- the last time, it was Richard Nixon, whose death was offered as a karmic explanation…
drorzel | April 9, 2008Over at Cosmic Variance, Julianne waxes rhapsodic about her calculator, a HP-15C. This is such an obvious Dorky Poll topic that I can't believe I didn't think of it earlier:
What sort of calculator do you use?
My students, particularly the future engineers, are always shocked by my answer:
I use a TI 30Xa. Actually, I don't know that off the top of my head-- I had to dig it out and look at it to come up with the model number. I think of it as "A $10 scientific calculator that I bought at Safeway."
This does everything I need, though-- it adds, subtracts, multiplies, divides, does square…
pontiff | April 8, 2008Whatever you do, Mr. and Mrs. Joe and Mary America, make sure to tell everyone you know not to go into science and engineering! You see those who major in science and engineering are certain to not get jobs, because, as many commenters love to point out, all those jobs are being exported overseas! But wait, what is this:
The overall unemployment rate of scientists and engineers in the United States dropped from 3.2% in 2003 to 2.5% in 2006...according to data from the National Science Foundation (NSF) Scientists and Engineers Statistical Data System (SESTAT). This is the lowest…
drorzel | April 8, 2008(This is the second of two background posts for a peer-reviewed research blogging post that has now slipped to tomorrow. I started writing it, but realized that it needed some more background information, which became this post. And now I don't have time to write the originally intended post...)
Making a quantum computer is a tricky business. The process of quantum computing requires the creation of both superposition states of individual quantum bits (in which the "qubit" is in some mixture of "0" and "1" at the same time) and also entangled states of different qubits (states where the state…
drorzel | April 8, 2008An ad-lib from yesterday's lecture about interactions between electric fields and neutral matter, paraphrased:
So, we can divide macroscopic objects into two categories, based on what happens when you bring large numbers of atoms together. In materials that are insulators, the electrons aren't free to move. The atoms hold onto their electrons very tightly. They're kind of like Republicans.
In materials that are conductors, on the other hand, the electrons are free to move. The atoms share their electrons freely through the whole material. They're basically Communists.
Semiconductors are like…
drorzel | April 7, 2008Having brought in a huge new audience at the end of last week-- partly through the "framing"/"screechy monkeys" things, but mostly because my What Everyone Should Know About Science post hit the front page on Reddit-- I figured I should take this opportunity to... Well, drive them all right the hell away again with a peer-reviewed physics post.
Unfortunately, I seem to have misplaced the papers I was going to write about, on experiments with qubits in diamond. They're probably on my desk at work, doing me no good at all. That's OK, though, because it would probably benefit from a little bit…
pontiff | April 6, 2008The Hawkman Speaketh at TED:
No alien quiz shows? Certainly Professor Hawking did not see Alex Trebek last week, when, for half the show, Alex Trebek had a really alien looking mustache.
drorzel | April 4, 2008I had the first lab of the term yesterday in my introductory E&M class. This is the first time I've taught out of this book (Matter & Interactions by Chabay and Sherwood), which actually includes the basic elements of this lab as suggested activities in the second chapter of the text. The lab was more successful than I expected (I've done the lab before), and I even managed to add a somewhat more free-form element to it, that worked out well.
The materials for the lab are extremely simple: One roll of "invisible" tape for each group, plus some sort of stand for them to stick tape to.…
drorzel | April 4, 2008The Perimeter Institute will be hosting a workshop in September on "Science in the 21st Century":
Times are changing. In the earlier days, we used to go to the library, today we search and archive our papers online. We have collaborations per email, hold telephone seminars, organize virtual networks, write blogs, and make our seminars available on the internet. Without any doubt, these technological developments influence the way science is done, and they also redefine our relation to the society we live in. Information exchange and management, the scientific community, and the society as a…
revere | April 2, 2008The World Wide Web began at the Swiss nuclear research facility, CERN (the European Organization for Nuclear Research), and that may be its biggest claim to fame. But CERN really is a nuclear research facility and is home to some of the most advanced technologies for probing the inner workings of matter, especially sub-atomic particles. For example, the Large Hadron Collider (LHC) is located there. Hadrons are composite subatomic particles composed of quarks. They come in two flavors, baryons (three quarks) and Mesons (a quark and an anti-quark). We learn in Wikipedia that hadrons are "single…
drorzel | April 2, 2008I have a doctor's appointment this morning, and then class, so here's another Dorky Poll inspired by the fact that I'm teaching intro E&M:
What system of units do you prefer for E&M: SI, or CGS?
This is even dorkier than usual, so I suppose I should provide some context...
The CGS system of units uses Centimeters, Grams, and Seconds as the base usints for everything, as opposed to the metere, kilograms, and seconds of the Systeme Internationale (also called MKS in some places). This doesn't make very much difference in mechanics, but it's a big deal in electromagnetism, because the…
scientificactivist | April 1, 2008The arguably wacky premise behind a New York Times article this Saturday is that the Large Hadron Collider (LHR)--slated to be the world's most impressive particle accelerator when it's up and running later this year--could inadvertently produce an Earth-destroying black hole. Or, that's at least what a couple of guys in Hawaii think, and they're pursuing a lawsuit in federal court there to stop it. (Note: the LHR is located in CERN... in Switzerland.)
Despite cries of "propaganda" from the plaintiffs, scientists aren't having any of that, and are trying to put all of this to rest with…