Experiment

Category archives for Experiment

One of the interesting things about the pile of old theses we found in the basement is the opportunity to look at things that nobody believes any more. Past installments of the Old Thesis Club have shown people fumbling toward an understanding of quantum physics via electron scattering and spectroscopy, but in both of those…

Finding That There’s Nothing to Find

In 1967, a team of scientists hauled a big pile of gear– electronics, particle detectors, a giant slab of iron– into the burial chamber at the base of one of the pyramids at Giza. This sounds like a scene from a science fiction or fantasy novel– throw in the fact that their first attempt was…

Two papers with a similar theme crossed my social media feeds in the last couple of days. You might think this is just a weird coincidence, but I’m choosing to take it as a sign to write about them for the blog. So, what are these papers, and what’s the theme? One is the final…

Quantum Erasure

When I posted congratulating the winner of this year’s Nobel betting pool, I received a gentle reminder in email that I’m a Bad Person and still haven’t done one of the posts I owe to the 2011 winners. Evan reminded me that he asked for something about the delayed-choice quantum eraser, so let’s talk about…

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…

As noted in a previous post on Monte Carlo simulation in 1960, we recently came into possession of a large box of old Master’s theses. The bulk of these are from the 50′s and 60′s, but there are some going back much farther. As I pass these every day I’m in the office, I thought…

When Is a Composite Object a Particle?

Through some kind of weird synchronicity, the title question came up twice yesterday, once in a comment to my TED@NYC talk post, and the second time on Twitter, in a conversation with a person whose account is protected, thus rendering it un-link-able. Trust me. The question is one of those things that you don’t necessarily…

Laser-Cooled Atoms: Ytterbium

Element: Ytterbium (Yb) Atomic Number: 70 Mass: Seven “stable” isotopes, from 168 to 176 amu. Two of those are nominally radioactive, with half-lives vastly in excess of the age of the universe. Laser cooling wavelength: 399 nm and 556 nm. Doppler cooling limit: 690 μK in the UV and 4.4 μK in the green. Chemical…

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…

Laser-Cooled Atoms: Chromium

Element: Chromium (Cr) Atomic Number: 24 Mass: Four “stable” isotopes between 50 and 54 amu. Chromium-50 is technically radioactive, with a half-life considerably longer than the age of the universe, so… Laser cooling wavelength: 425nm, but see below. Doppler cooling limit: 120 μK. Chemical classification: Transition metal, smack in the middle of the periodic table.…