Category: Atoms and Molecules

Tools of the Cold-Atom Trade: Light Scattering Forces and Slow Atomic Beams

Ryan McMartin '05 next to the Zeeman slower he built in my lab.

This series of posts is intended to explain the tools and tricks used to create and manipulate samples of ultra-cold atoms; thus, it’s appropriate to start with how we get those atoms in the first place. This will be a very quick background on the basic force used to make atoms cold, and then the… Continue reading Tools of the Cold-Atom Trade: Light Scattering Forces and Slow Atomic Beams

Tools of the Cold-Atom Trade: Introduction

Me and Emmy with some of the laser cooling apparatus in my lab.

I have a small collection of recent research papers that I’d like to write up open in various browser tabs and suchlike, but many of these would benefit from having some relatively clear and compact explanations of the underlying techniques. And while I can either dig up some old posts, or Google somebody else’s, it’s… Continue reading Tools of the Cold-Atom Trade: Introduction

The Making of a Sign Error

The Bose-Hubbard Hamiltonian, in the notation I used in the squeezed state paper.

One thing I left out of the making-of story about the squeezed state BEC paper last week happened a while after publication– a few months to a year later. I don’t quite recall when it was– I vaguely think I was still at Yale, but I could be misremembering. It’s kind of amusing, in an… Continue reading The Making of a Sign Error

The Making of “Squeezed States in a Bose-Einstein Condensate”

A 3-d rendering of the squeezed state data, created in an unsuccessful bid for the cover of Science.

Yesterday’s write-up of my Science paper ended with a vague promise to deal some inside information about the experiment. So, here are some anecdotes that you would need to have been at Yale in 1999-2000 to pick up. We’ll stick with the Q&A format for this, because why not? Why don’t we start with some… Continue reading The Making of “Squeezed States in a Bose-Einstein Condensate”

My Claim to Scientific Fame: “Squeezed States in a Bose-Einstein Condensate”

A version of Figure 4 from the paper discussed in the post, taken from an old talk.

In Monday’s post on squeezed states, I mentioned that I really liked the question because I had done work on the subject. This is, in fact, my claim to scientific fame (well, before the talking-to-the-dog thing, anyway)– I’m the first author on a Science paper with more than 500 citations having to do with squeezed… Continue reading My Claim to Scientific Fame: “Squeezed States in a Bose-Einstein Condensate”

Atom by Atom Interaction: “Direct Measurement of the van der Waals Interaction between Two Rydberg Atoms”

Figure 2 from the paper described in the text.

I’m always a little ambivalent about writing up papers that have also been written up in Physics: on the one hand, they make a free PDF of the paper available, which allows me to reproduce figures from the paper in my post, since I’m not breaking a paywall to do it. Which makes it much… Continue reading Atom by Atom Interaction: “Direct Measurement of the van der Waals Interaction between Two Rydberg Atoms”

Of Controversies and Clocks

Schematic of an atom interferometer or clock comparison, from Hohensee et al., http://arxiv.org/abs/1102.4362

A few months back, I got a call from a writer at a physics magazine, asking for comments on a controversy within AMO physics. I read a bunch of papers, and really didn’t quite understand the problem; not so much the issue at stake, but why it was so heated. When I spoke to the… Continue reading Of Controversies and Clocks

Few-Body Systems: Cooler Than You Might Think

Figure 2 from the arxiv version of the preparation paper.

Hey, dude? Yeah, what’s up? I’m not normally the one who initiates this, but I was wondering: When you were at DAMOP last week, did you see any really neat physics? Oh, sure, tons of stuff. It was a little thinner than some past meetings– a lot of the Usual Suspects didn’t make the trip–… Continue reading Few-Body Systems: Cooler Than You Might Think

Time Is What You Measure With a Clock

Figure from How to teach Relativity to Your Dog, showing the inability of moving observers to synchronize their clocks.

Last year, Alan Alda posed a challenge to science communicators, to explain a flame in terms that an 11-year old could understand. this drew a lot of responses, and some very good winners. This year’s contest, though still called the “Flame Challenge,” asked for an answer to the question “What Is Time?” This is a… Continue reading Time Is What You Measure With a Clock

How Do You Make Negative Temperatures, Anyway?

Part of Figure 1 from the arxiv preprint of the paper discussed in the post.

Last week’s post talked about the general idea of negative temperature, with reference to this much-talked-about Science paper (which also comes in a free arxiv version from which the figures used here are taken). I didn’t go into the details of how they made a negative temperature gas, though, and as it’s both very clever… Continue reading How Do You Make Negative Temperatures, Anyway?