research-blogging
drorzel | June 4, 2012In which we do a little ResearchBlogging, taking a look at a slightly confusing paper putting a new twist on the double-slit experiment.
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I'm off to California this afternoon, spending the rest of the week at DAMOP in Pasadena (not presenting this year, just hanging out to see the coolest new stuff in Atomic, Molecular, and Optical Physics). I don't want to leave the blog with just a cute-kid video for the whole week, though, so here's some had-core physics: a new paper in the Proceedings of the National Academy of Sciences (freely available online), looking at a new sort of…
drorzel | May 27, 2011The big physics story of the week is undoubtedly the new limit on the electric dipole moment (EDM) of the electron from Ed Hinds's group at Imperial College in the UK. As this is something I wrote a long article on for Physics World, I'm pretty psyched to see this getting lots of media attention, and not just from physics outlets.
My extremely hectic end-of-term schedule and general laziness almost make me want to just point to my earlier article and have done with it. But really, it's a big story, and one I've been following for a while, so how can I pass up the chance for a ResearchBlogging…
drorzel | May 16, 2011Physics is a notoriously difficult and unpopular subject, which is probably why there is a large and active Physics Education Research community within physics departments in the US. This normally generates a lot of material in the Physical Review Special Topics journal, but last week, a PER paper appeared in Science, which is unusual enough to deserve the ResearchBlogging treatment.
OK, what's this paper about? Well, with the exceptional originality that physicists bring to all things, the title pretty much says it all. They demonstrated that a different style of teaching applied to a large…
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 | 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 | August 30, 2010Last week, John Baez posted a report on a seminar by Dzimitry Matsukevich on ion trap quantum information issues. In the middle of this, he writes:
Once our molecular ions are cold, how can we get them into specific desired states? Use a mode locked pulsed laser to drive stimulated Raman transitions.
Huh? As far as I can tell, this means "blast our molecular ion with an extremely brief pulse of light: it can then absorb a photon and emit a photon of a different energy, while itself jumping to a state of higher or lower energy."
I saw this, and said "Hey, that's a good topic for a blog post…
drorzel | August 26, 2010There's a minor scandal in fundamental physics that doesn't get talked about much, and it has to do with the very first fundamental force discovered, gravity. The scandal is the value of Newton's gravitational constant G, which is the least well known of the fundamental constants, with a value of 6.674 28(67) x 10-11 m3 kg-1 s-2. That may seem pretty precise, but the uncertainty (the two digits in parentheses) is scandalously large when compared to something like Planck's constant at 6.626 068 96(33) x 10-34 J s. (You can look up the official values of your favorite fundamental constants at…
drorzel | August 25, 2010The Joerg Heber post that provided one of the two papers for yesterday's Hanbury Brown Twiss-travaganza also included a write-up of a new paper in Nature on Mott insulators, which was also written up in Physics World.
Most of the experimental details are quite similar to a paper by Markus Greiner's group I wrote up in June: They make a Bose-Einstein Condensate, load it into an optical lattice, and use a fancy lens system to detect individual atoms at sites of the lattice. This lattice can be prepared in a "Mott insulator" state, where each site is occupied by a definite number of atoms. As…
drorzel | August 24, 2010Two papers in one post this time out. One of these was brought to my attention by Joerg Heber, the other I was reminded of when checking some information for last week's mathematical post on photons. They fit extremely well together though, and both relate to the photon correlation stuff I was talking about last week.
OK, what's the deal with these? These are two papers, one recent Optics Express paper from a week or so ago, the other a Nature article from a few years back. The Nature paper includes the graph you see at right, which is a really nice dataset demonstrating the Hanbury Brown and…
drorzel | August 23, 2010I'm a big fan of review articles. For those not in academic science, "review article" means a long (tens of pages) paper collecting together the important results of some field of science, and presenting an overview of the whole thing. These vary somewhat in just how specific they are-- some deal with both experiment and theory, others just theoretical approaches-- and some are more readable than others, but typically, they're written in a way that somebody from outside the field can understand.
These are a great boon to lazy authors, or authors facing tight page limits ("Ref. [1] and…
drorzel | July 27, 2010When one of the most recent issues of Physical Review Letters hit my inbox, I immediately flagged these two papers as something to write up for ResearchBlogging. This I looked at the accompanying viewpoint in Physics, and discovered that Chris Westbrook already did most of the work for me. And, as a bonus, you can get free PDF's of the two articles from the Physics link, in case you want to follow along at home.
Since I spent a little time thinking about these already, though, and because it connects to the question of electron spin that I talked about yesterday, I think it's still worth…
drorzel | July 23, 2010This week's big story in physics is this Science paper by a group out of Austria Canada (edited to fix my misreading of the author affiliations), on a triple-slit interference effect. This has drawn both the usual news stories and also some complaining about badly-worded news stories. So, what's the deal?
What did they do in this paper? The paper reports on an experiment in which they looked at the interference of light sent through a set of three small slits, and verified that the resulting pattern agrees with the predictions of the Born rule for quantum probabilities.
What does Matt Damon…
drorzel | January 12, 2009 There's been a fair bit of press for the article Subtracting photons from arbitrary light fields: experimental test of coherent state invariance by single-photon annihilation, published last month in the New Journal of Physics, much of it in roughly the same form as the news story in Physics World (which is published by the same organization that runs the journal), which leads with:
A property of laser light first predicted in 1963 by the future Nobel laureate Roy Glauber has been verified by physicists in Italy.
These stories can be a little puzzling, though. After all, Glauber got his…