Category: Experiment

Without Experiment, There Is No Theory

A lot of people have been blogging and Twittering about this subway map of science, which puts various branches of science in the place of the lines on the London Underground map, showing connections between them. It’s a huge graphic, but a kind of cool image. I do, however, have a problem with it, which… Continue reading Without Experiment, There Is No Theory

Backyard Fluid Dynamics Revisited

Back in July, I did a post looking at how the fountain in our ornamental backyard pond shoots higher when the level of the pond drops. I set up a simple model of the process, which worked surprisingly well, but I said at the time that I really needed more data to say whether that… Continue reading Backyard Fluid Dynamics Revisited

Measuring Gravity: Ain’t Nothin’ but a G Thing

There’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… Continue reading Measuring Gravity: Ain’t Nothin’ but a G Thing

Melting Simulated Insulators

The 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… Continue reading Melting Simulated Insulators

Bunches and Antibunches of Atoms: Hanbury Brown and Twiss Effects in Ultracold Atoms

Two 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… Continue reading Bunches and Antibunches of Atoms: Hanbury Brown and Twiss Effects in Ultracold Atoms

High Excitement in Review: “Quantum information with Rydberg atoms”

I’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… Continue reading High Excitement in Review: “Quantum information with Rydberg atoms”

What Do You Need to Make Cold Atoms? Appendix: “No-Laser” Methods

Last week’s series of posts on the hardware needed for laser cooling and trapping experiments dealt specifically with laser-cooling type experiments. It’s possible, though, to make cold atoms without using laser cooling, using a number of techniques I described in two posts back in January. Those didn’t go into the hardware required, though, so what’s… Continue reading What Do You Need to Make Cold Atoms? Appendix: “No-Laser” Methods

What Do You Need to Make Cold Atoms? Part 3: Test and Measurement

The third category in our look at lab apparatus, after vacuum hardware and lasers and optics is the huge collection of electronic gear that we use to control the experiments. I’ll borrow the sales term “test and measurement” as a catch-all description, though this is really broader than what you’ll usually find in that category.… Continue reading What Do You Need to Make Cold Atoms? Part 3: Test and Measurement

Do Not Look In Laser Pointer With Remaining Eye

Some folks I used to work with at NIST have looked at cheap green laser pointers, and found a potential danger. Some of the dimmer-looking green lasers are not so dim in the infrared, and in one case emitted 10X the rated power in invisible light. This could be a potential eye hazard. You can… Continue reading Do Not Look In Laser Pointer With Remaining Eye