Interstellar Laser Communications

In the comments to yesterday’s grumpy post about the Fermi paradox, makeinu raises the idea that advanced aliens would be using more targeted communications than we do: On the point about electromagnetic communications: even we are now using lasers to target communications with space, because it’s simply more efficient and reliable. It’s also basically impossible […]

Cosmos Reboot: On Light

Another Monday, another recap of a new episode of the Cosmos reboot. This one was all about optics, and much of it was excellent. This was in part due to the fact that its first couple of historical segments focused on non-Western figures, and I don’t know as much about their background to be able […]

On Computer Color

This year’s “Flame Challenge” is to explain color in terms an 11-year-old can follow. I have opinions on this subject, a background in AMO physics, and access to scientific equipment, so I’m putting something together. In the course of this, though, it occurred to me to wonder how my different portable computing devices process color. […]

Interference with 10,000-Particle “Particles”: “Matter-wave interference with particles selected from a molecular library with masses exceeding 10000 amu”

I’m teaching Quantum Optics this term, and one of my students picked “Atom Optics” off the list of suggested paper topics. When he asked for pointers, I said “You should check out the diffraction stuff Markus Arndt’s group does.” And just like that, a paper from the Arndt group turns up from the Arxiv Blog… […]

Old Thesis Club: The Hyperfine Structure and Zeeman Effect for Mercury Resonance Line 2536.52A by Leo Wilson Scott, 1932

Having spent a bunch of time talking about heavy stuff in the science blogging community, let’s unwind a bit and kick the week off with a look back at an old Master’s thesis. This one is from 1932, and is almost certainly a draft copy, because it’s extremely cheaply bound in cardboard with the title […]

Laser-Cooled Atoms: Cesium

Element: Cesium (Cs) Atomic Number: 55 Mass: One stable isotope, mass 133 amu. Laser cooling wavelength: 854nm, but see below. Doppler cooling limit: 125 μK. Chemical classification: Yet another alkali metal, column I of the periodic table. This one isn’t greyish, though! It’s kind of gold color. Still explodes violently in water, though. Other properties […]