adrian

I'm so relieved that my poster is finished. The co-authors seem to like it. It's now printed out on a huge, 3 ft x 4 ft sheet of glossy paper, rolled up in a cardboard tube. My schedule for the next couple weeks is insane, but having the poster finished makes it at least seem tractible.

Yesterday Adrian took me and his grad student Stefanos out to lunch at Phillip's European to bring in the holidays, after a long discussion about LIGO -- how it works and what we'll do there. Adrian Melissinos. We met when he wandered into the lab session I teach, having heard of this "Berkeley kid who knows Linux." He quizzed my students, and asked if I wanted to go do some work at LIGO for a week. "Yes, yes I do." So now it's all arranged. Adrian is a wonderful man, and already I've found myself using the phrase, "my advisor," although putatively this is just a quick mission to LIGO in preparation for data taking and I'd really like to get involved in quantum optics.

Amusingly, the phenomena under investigation in our last two homework problems in electrodynamics came up directly in our discussion of LIGO. One problem was to show that light traveling through a dielectric (say, glass) with a static magnetic field pointing in the direction of propagation, will have its polarization rotated. The other is to show that a binary system of two charges of the same sign orbitting each other will produce quadrapole radiation. Well, the first effect is used in LIGO to form a sort of "one way" valve (diode?) for light. A laser shines through a polarized beamsplitter and then through a dielectric in parallel with a static magnetic field; the light has its polarization rotated by 45 degrees before entering the interferometer. Any light reflected out of the interferometer passes back through the polarization-rotator, having its polarization rotated by another 45 degrees. At this point the reflected light has polarization 90 degrees out of phase with the entering light, and is ejected from the system by the polarized beamsplitter. Neat. (Apparently this is called a Faraday isolator.) And the system of two like-signed charges in a binary orbit generates quadrapole electromagnetic radiation in exactly the same way a system of two starts in a binary orbit will generate quadrapole gravitational waves — a signal that LIGO is hoped to observe.

It's snowing now outside, big soggy flakes of ice kissing the earth. For breakfast Micah (milinovich) made pastrami/potato hash. mmmm. This afternoon all of us are going over to Brette's house for Hannukah dinner.