Experiment
drorzel | April 21, 2011Several people blogged about a new measurement of gravitational states of neutrons done by physicists using ultracold neutrons from the Institut Laue-Langevin in France. I had to resort to Twitter to get access to the paper (we don't get Nature Physics here, and it's way faster than Inter-Library Loan), but this is a nice topic for a ResearchBlogging post, in the now-standard Q&A form:
OK, why was this worth begging people on Twitter to send you a copy? The paper is a demonstration of a sort of spectroscopy of neutrons bouncing in a gravitational field. They showed they could drive…
drorzel | April 18, 2011 It's been a while since I wrote up a ResearchBlogging post, but since a recent paper forced me to update my "What Every Dog Should Know About Quantum Physics" slides with new pictures, I thought I should highlight the work on the blog as well. Not that you could've missed it, if you follow physics-y news-- it's been all over, getting almost as much press as rumors that some people whose funding will run out soon saw something intriguing in their data. So, in the usual Q&A format:
OK, what's this about? Well, the paper title, "Quantum interference of large organic molecules" pretty well…
drorzel | January 14, 2011The physics book generating the most bloggy buzz in the latter part of 2010 would have to be Ian Sample's Massive: The Missing Particle that Sparked the Greatest Hunt in Science, about the as yet undetected particle known as the Higgs boson. Detecting the Hiigs is the most immediate goal of the Large Hadron Collider, so it's a topic that's in the air at the moment, so this book was inevitable-- in fact, the publisher sent me not one but two review copies. I gave one away, but that makes me feel even more guilty for taking months to get around to reviewing it.
This is, basically, a concise…
drorzel | January 12, 2011Another response copied/adapted from the Physics Stack Exchange. The question was:
What are the main practical applications that a Bose-Einstein condensate can have?
Bose Einstein Condensation, for those who aren't familiar with it, is a phenomenon where a gas of particles with the right spin properties cooled to a very low temeprature will suddenly "condense" into a state where all of the atoms in the sample occupy the same quantum wavefunction. This is not the same as cooling everything to absolute zero, where you would also have everything in the lowest energy state-- at the temperatures…
drorzel | December 29, 2010Most of what would ordinarily be blogging time this morning got used up writing a response to a question at thePhysics Stack Exchange. But having put all that effort in over there, I might as well put it to use here, too...
The question comes from a person who did a poster on terminology at the recently concluded American Geophysical Union meeting, offering the following definition of "data":
Values collected as part of a scientific investigation; may be qualified as 'science data'. This includes uncalibrated values (raw data), derived values (calibrated data), and other transformations of…
drorzel | December 28, 2010It's the last week of the (calendar) year, which means it's a good time to recap the previous twelve months worth of scientific news. Typically, publications like Physics World will publish a list of top ten physics stories of 2010, but we're all Web 2.0 these days, so it seems more appropriate to put this to a poll:
What is the top physics story of 2010?survey software
I've used the Physics World list as a starting point, because you have to start somewhere. I added a few options to cover the possibility that they left something out, and, of course, you know where the comments are.
This poll…
drorzel | December 7, 2010Today is the official release date for the paperback edition of How to Teach Physics to Your Dog, so I wanted to write up something cool about quantum physics to mark the occasion. I looked around the house for inspiration, and most of what we have lying around the house is SteelyKid's toys. Thus, I will now explain the physics of quantum teleportation using SteelyKid's toys:
"Wait, wait, wait... You're not seriously planning to explain something quantum without me, are you?"
"I could hardly expect to get away with that, could I. No, I'm happy to have your contributions-- the book is about…
drorzel | December 1, 2010I hadn't heard anything about Dance of the Photons: From Einstein to Quantum Teleportation before it turned up in my mailbox, courtesy of some kind publicist at Farrar, Straus, and Giroux, otherwise I would've been eagerly anticipating it. Anton Zeilinger is a name to conjure with in quantum optics, having built an impressive career out of doing laboratory demonstrations of weird quantum phenomena. He shared the Wolf Prize earlier this year with John Clauser and Alain Aspect, and the three of them are in a small set of people who probably ought to get a Nobel at some point in the near future…
drorzel | November 19, 2010Earlier this week, I talked about the technical requirements for taking a picture of an interference pattern from two independent lasers, and mentioned in passing that a 1967 experiment by Pfleegor and Mandel had already shown the interference effect. Their experiment was clever enough to deserve the ResearchBlogging Q&A treatment, though, so here we go:
OK, so why is this really old experiment worth talking about? What did they do? They demonstrated interference between two completely independent lasers, showing that when they overlapped the beams, the overlap region contained a pattern…
drorzel | November 17, 2010The big physics-y news story of the moment is the trapping of antihydrogen by the ALPHA collaboration at CERN. The article itself is paywalled, because this is Nature, but one of the press offices at one of the institutions involved was kind enough to send me an advance version of the article. This seems like something that deserves the ResearchBlogging Q&A treatment, so here we go:
OK, what's the deal with this paper? Well, the ALPHA collaboration is announcing that they have created antihydrogen atoms-- that is, a single antiproton orbited by a single positron-- at low temperatures, and…
drorzel | November 15, 2010This is adapted from an answer to a question at the Physics Stack Exchange site. The questioner asked:
It seems that if the coherence length of a laser is big enough, it is possible to observe a (moving) interference picture by combining them. Is it true? How fast should photo-detectors be for observing of the interference of beams from two of the "best available" lasers?
This is a question about the itnerference of light waves, which is traditionally demonstrated via the famous "double slit" experiment, where a single laser is sent through a barrier with two narrow slits cut in it. The…
drorzel | November 12, 2010As mentioned in yesterday's post on ion trapping, a month or so back Dave Wineland's group at NIST published a paper in Science on using ultra-precise atomic clocks to measure relativistic effects. If you don't have a subscription to Science, you can get the paper for free from the Time and Frequency Division database, because you can't copyright work done for the US government.
This paper generated quite a bit of interest when it came out, because it demonstrates the time-slowing effects of relativity without any need for exotic objects like black holes or particle accelerators-- they deal…
drorzel | November 11, 2010One of the many physics stories I haven't had time to blog about recently is the demonstration of relativistic time effects using atomic clocks. I did mention a DAMOP talk about the experiment, but the actual paper was published in Science (and is freely available from the NIST Time and Frequency Division (PDF file), because you can't copyright work done at government labs) a month and a half ago, and generated a bit of buzz at the time.
Given the delay between publication of the article and me blogging about it, I feel obliged to provide a little more detail than you'll get from the news…
drorzel | November 2, 2010Today's a lab day in my main class for the term, with a fairly involved experiment to measure the charge-to-mass ratio of the electron. This is going to be all kinds of fun, because 1) I can't get into the room to set anything up until an hour before the start of class, and 2) SteelyKid is home sick, which means I can't go in to pull stuff together until about an hour before the start of class. Whee!
Today's a day to (attempt to) accentuate the positive, though, so let's use this as a jumping-off point for a more upbeat topic, namely:
What's the best lab you ever did in a lab science class?…
drorzel | October 22, 2010As promised, an answer to a question from a donor to this year's DonorsChoose Blogger Challenge. Sarah asks:
Chad, can I get a post about how you (or scientists in general) come up with ideas for experiments? You've covered some of the gory detail with the lab info posts, but I think it would be useful for your readers to see where the ideas come from.
The answer is obvious: Ideas come from Schenectady. Which, not coincidentally, is where I live...
More seriously, in my area of experimental physics, I think there are two main ways people come up with ideas for new experiments:…
drorzel | October 13, 2010Melissa at Confused at a Higher Level offers some thoughts on the relative status of experimental vs. theoretical science, spinning off a comprehensive discussion of the issues at Academic Jungle. I flagged this to comment on over the weekend, but then was too busy with SteelyKid and football to get to it. since I'm late to the party, I'll offer some slightly flippant arguments in favor of experiment or theory:
Argument 1: Experimentalists are better homeowners. At least in my world of low-energy experimental physics, many of the skills you are expected to have as an experimental physicist…
drorzel | October 5, 2010The 2010 Nobel Prize in Physics goes to Geim and Novoselov for their work on graphene, a material consisting of one-atom-thick sheets of carbon atoms in a hexagonal array. This is one of those prizes that was basically inevitable, as graphene is one of the hot materials of the last couple of years. Hardly a week goes by without a couple of press releases touting some amazing new potential application.
Joerg Heber has a nice explanation of the basics of graphene, including some cautionary notes about overhype. From an experimentalist's perspective, the really cool thing about this prize is…
drorzel | September 14, 2010Not long ago, a new preprint on the fine structure constant got a bunch of press, nicely summed up by the Knight Science Journalism Tracker last week. I meant to say something about this last week, but what with it being the first week of classes and all, I didn't find the time.
I still think it's worth writing about, though, so after a reproduction of the key figure, we'll have the usual Q&A-format explanation of why I don't quite trust this result:
So what's this all about? The preprint in question is the latest in a series of attempts to measure possible changes in the fine structure…
drorzel | September 9, 2010Over at Tor.com, Jo Walton is surprised that people skim over boring bits of novels. While she explicitly excludes non-fiction from her discussion, this immediately made me think of Timothy Burke's How to Read in College, which offers tips to prospective humanities and social science majors on how to most effectively skim through huge reading assignments for the information that's really important.
I've mentioned this before, but I don't think I've done a science version. I've been doing more reading of journal articles lately than I have in a while, though, and it occurs to me that similar…
drorzel | September 3, 2010Over at Confused at a Higher Level, Melissa offers an alphabetical list of essential supplies for a condensed matter experimentalist at a small college. This is a fun idea for back-to-school time, so I'll steal it, and offer the following alphabetical list of essentials for Atomic, Molecular, and Optical physics at a small college, kind of a condensed version of the three part series I did a few weeks ago.
A is for Acousto-optic modulator This is a device that uses sound waves in a crystal to deflect light and shift its frequency. It's essential for rapid control of laser properties.
B is for…