interference

It's been a long and brutally busy week here, so I really ought to just take a day off from blogging. But there's a new paper in Science on quantum physics that's just too good to pass up, so here's a ReasearchBlogging post to close out the week. Aw, c'mon, dude, I'm tired. What's so cool about this paper that it can't wait until next week? Well, the title kind of says it all: they measured the average trajectories of single photons passing through a double-slit apparatus. By making lots of repeated weak measurements at different positions behind the slits, they could reconstruct the average…
Earlier this week, I talked about the technical requirements for taking a picture of an interference pattern from two independent lasers, and mentioned in passing that a 1967 experiment by Pfleegor and Mandel had already shown the interference effect. Their experiment was clever enough to deserve the ResearchBlogging Q&A treatment, though, so here we go: OK, so why is this really old experiment worth talking about? What did they do? They demonstrated interference between two completely independent lasers, showing that when they overlapped the beams, the overlap region contained a pattern…
This week's big story in physics is this Science paper by a group out of Austria Canada (edited to fix my misreading of the author affiliations), on a triple-slit interference effect. This has drawn both the usual news stories and also some complaining about badly-worded news stories. So, what's the deal? What did they do in this paper? The paper reports on an experiment in which they looked at the interference of light sent through a set of three small slits, and verified that the resulting pattern agrees with the predictions of the Born rule for quantum probabilities. What does Matt Damon…
I'm a little cranky after a day of reviewing grant proposals, so it's possible that I'm overreacting. But commenter Neil B has been banging on about quantum measurement for weeks, including not one, not two, but three lengthy comments in Tuesday's dog post. For that reason, I am declaring this post's comments section to be the Official Neil B. Quantum Measurement Thread. Until such time as I declare the subject open again, this is the only thread in which I want to see comments about quantum measurement. Attempts to bring the subject up in comments to other posts-- even other posts having to…