Theory

Category archives for Theory

In the previous post about simulating the attraction between sticky tapes using VPython, I ended with a teaser mentioning that there was a discrepancy between the simulation and the theoretical solution from directly solving the equations. The problem is kind of subtle, but clearly visible in this graph from that post: In this, we see…

Simulated Tape and Universal Behavior

Having spent a lot of time solving equations related to sticky tape models, including trying to work solutions in my head while driving to Grandma and Grandpa’s with the kids, and making some measurements of real tapes, there was only one thing left to do: try simulating this problem in VPython. Because I’m a physics…

Keeping BEC Cold

I know I said there weren’t going to be physics posts for a while, but yesterday our Communications office passed along a media request about this paper on feedback cooling of BEC, from some sort of communications-person mailing list. I’d seen it talked up elsewhere– here, for example, so I banged out an email to…

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…

Free, As In Energy

Via social media, John Novak cashes in a Nobel Betting Pool win from a while back, asking: Please explain to me the relationship between energy, entropy, and free energy. Like you would explain it to a two year old child. Why? There is a statistical algorithm called Expectation Maximization which is often explained in terms…

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…

Quantum Viruses?

The Twitter conversation that prompted yesterday’s post about composite objects was apparently prompted by a comment somebody made about how a virus left alone would see its quantum wavefunction spread out on a time scale of minutes. This led to wondering about whether a virus could really be considered a particle that would move as…

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…