I got forwarded a physics question last night asking about the connection between wind and temperature, which I’ll paraphrase as: Temperature is related to the motion of the atoms and molecules making a substance up, with faster motion corresponding to higher temperature. So why does it feel warmer when the air is still and why… Continue reading Wind and Temperature: Why Doesn’t Windy Equal Hot?
Category: Atoms and Molecules
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 2: Lasers and Optics
Following on yesterday’s discussion of the vacuum hardware needed for cooling atoms, let’s talk about the other main component of the apparatus: the optical system. The primary technique used for making cold atoms is laser cooling, and I’m sure it will come as no surprise that this requires lasers, and where there are lasers, there… Continue reading What Do You Need to Make Cold Atoms? Part 2: Lasers and Optics
What Do You Need to Make Cold Atoms? Part 1: Vacuum Hardware
Over in the reader request thread, Richard asks for experimental details: I’d be interested in (probably a series) of posts on how people practically actually do cold atoms experiments because I don’t really know. I needed to take some new publicity photos of the lab anyway, so this is a good excuse to bust out… Continue reading What Do You Need to Make Cold Atoms? Part 1: Vacuum Hardware
Cold Atoms and Cooper Pairs
So, last week, I talked about how superconductors work, and I have in the past talked about the idea of making cold atoms look like electrons. And obvious question, then, whould be: Do cold atoms systems allow us to learn anything about superconductivity? The answer here is, unfortunately, “Yes and no.” That’s pretty weaselly, dude.… Continue reading Cold Atoms and Cooper Pairs
What’s a Photon, and How Do We Know they Exist?
A reader emailed me with a few questions regarding How to Teach Physics to Your Dog, one of which is too good not to turn into a blog post: What is a photon from an experimental perspective?… Could you perhaps provide me with a reference that discusses some experiments and these definitional issues? The short… Continue reading What’s a Photon, and How Do We Know they Exist?
Murphy Violation in Science
Over at Unqualified Offerings, Thoreau proposes an an experimental test of Murphy’s Law using the lottery. While amusing, it’s ultimately flawed– Murphy’s Law is something of the form: Anything that can go wrong, will. Accordingly, it can only properly be applied to situations in which there is a reasonable expectation of success, unless something goes… Continue reading Murphy Violation in Science
Measuring Temperature by Counting Atoms: “Suppressed Fluctuations in Fermi Gases”
When 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… Continue reading Measuring Temperature by Counting Atoms: “Suppressed Fluctuations in Fermi Gases”
Electron Spin for Toddlers
The subject of the “spin” of the electron comes up again and again, so as pointed out in a comment, I really ought to do a post explaining what it is and how it works. As a bonus, this gives me the opportunity to do the dorkiest thing anyone has ever done with a cute-toddler… Continue reading Electron Spin for Toddlers
Holy Grails of Science
With the rumors of a Higgs Boson detected at Fermilab now getting the sort of official denial that in politics would mean the rumors were about to be confirmed in spectacular fashion, it’s looking like we’ll have to wait a little while longer before the next “Holy Grail” of physics gets discovered. Strictly speaking, the… Continue reading Holy Grails of Science