Theory

Category archives for Theory

Fun With Simulated Scattering

Two chapters of the book-in-progress will be devoted to the development of the modern understanding of the atom. One of these is about the Bohr model, which turned 100 this year, but Bohr’s model would not have been possible without an earlier experiment. The actual experiment was done by Ernest Marsden and Hans Geiger, but…

Spooky Action at What Distance?

When I wrote up the giant interferometer experiment at Stanford, I noted that they’ve managed to create a situation where the wavefunction of the atoms passing through their interferometer contains two peaks separated by almost a centimeter and a half. This isn’t two clouds of atoms each definitely in a particular position, mind, this is…

I’m writing a bit for the book-in-progress about neutrinos– prompted by a forthcoming book by Ray Jaywardhana that I was sent for review– and in looking for material, I ran across a great quote from Arthur Stanley Eddington, the British astronomer and science popularizer best known for his eclipse observations that confirmed the bending of…

Driving a Simulated Pendulum

Some time back, I spent a bunch of time writing a VPython program that simulated the motion of a pendulum, which turned out to do some strange things. In the comments to that, there were two things worth mentioning: first and foremost, Arnoques at #5 spotted a small error in the code that fixes the…

Naming Names in QED

I’m doing edits on the QED chapter of the book-in-progress today, and I’m struck again by the apparent randomness of the way credit gets attached to things. QED is a rich source of examples of this, but two in particular stand out, one experimental and the other theoretical. On the experimental side, it’s interesting to…

The Making of a Sign Error

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…

I spend a lot of time promoting Rhett Allain’s Dot Physics blog, enough that some people probably wonder if I get a cut of his royalties (I don’t). I’m going to take issue with his latest, though, because he’s decided to revive his quixotic campaign against photons, or at least teaching about photons early in…

What Is Squeezing?

In the Physics Blogging Request Thread the other day, I got a comment so good I could’ve planted it myself, from Rachel who asks: It’s a term I see used a lot but don’t really know what it means – what is a “squeezed state”? What does “squeezing” mean? (in a QM context of course…)…

Of Controversies and Clocks

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…

A little while back, I posted about the pro-theorist bias in popular physics, and Ashutosh Jogalekar offers a long and detailed response, which of course was posted on a day when I spent six hours driving to Quebec City for a conference. Sigh. Happily, ZapperZ and Tom at Swans On Tea offer more or less…