Category: Experiment

A Confusing Light OPERA: How Does a Loose Fiber Optic Cable Cause a Signal Delay?

So, the infamous OPERA result for neutrino speeds seems to be conclusively disproven, traced to a problem with a timing signal. Matt Strassler has a very nice explanation of the test that shows that the whole thing can almost certainly be traced to a timing error that cropped up in 2008. This problem is generally… Continue reading A Confusing Light OPERA: How Does a Loose Fiber Optic Cable Cause a Signal Delay?

Treating Big Molecules Like Electrons: “Real-time single-molecule imaging of quantum interference”

Richard Feyman famously once said that the double-slit experiment done with electrons contains everything that’s “‘at the heart of quantum physics.” It shows both particle and wave character very clearly: the individual electrons are detected one at a time, like particles, but the result of a huge number of detections clearly traces out an interference… Continue reading Treating Big Molecules Like Electrons: “Real-time single-molecule imaging of quantum interference”

Neutrinos in the News

A little more tab clearance, here, this time a few recent stories dealing with those elusive little buggers, neutrinos. In roughly chronological order:< /p> The Daya Bay experiment in China has measured a key parameter for neutrino oscillation (arxiv paper), the phenomenon where neutrinos of one of the three observed types slowly evolve into one… Continue reading Neutrinos in the News

Experimental Particle Physics: Still Really Difficult

So, the news of the moment in high-energy physics is the latest results being reported from a conference in Europe. The major experimental collaborations are presenting their newest analyses, sifting through terabyte-size haystacks of data looking for the metaphorical needle that is the Higgs boson. And what are those results? It sort of depends on… Continue reading Experimental Particle Physics: Still Really Difficult

On Neutrinos and Cables

It’s not a good week for me to be writing about anything remotely controversial, but if I want to keep my physics blogging license, I need to say something about the latest fast neutrino news. This has followed the usual trajectory of such stories, with the bonus farcical element of people who blasted the media… Continue reading On Neutrinos and Cables

Most Difficult Course?

Regular reader Johan Larson sends in a good question about academic physics: You have written about teaching various courses in modern physics, a subject that has a fearsome reputation among students for skull-busting difficulty. That suggests a broader question: what is the most difficult course at your university? Or even more broadly, how would one… Continue reading Most Difficult Course?

Course Report: A Brief History of Timekeeping 03

It’s been a little while since I wrote up what I’ve been doing in my “Brief History of Timekeeping” class, because I was out of town, and then catching up from being out of town. Some of this material has already appeared here, though, so I can hopefully catch up a lot of stuff in… Continue reading Course Report: A Brief History of Timekeeping 03

Experiment vs. Theory: Where Did It All Go Wrong?

Over at Backreaction, Bee is running an advent calendar of her own, with amusing anecdotes about famous physicists. Apparently, it’s a good year for advent calendars. A couple of days ago, her story was a famous one about Heisenberg nearly failing to get his Ph.D. because he disdained experiment: Wien wanted to fail Heisenberg, but… Continue reading Experiment vs. Theory: Where Did It All Go Wrong?

The Top Physics Breakthroughs of 2011

Physics World has released its list of the top ten breakthroughs in physics for the year, and it doesn’t include either fast neutrinos or the Higgs boson: The two physics stories that dominated the news in 2011 were questions rather than solid scientific results, namely “Do neutrinos travel faster than light?” and “Has the Higgs… Continue reading The Top Physics Breakthroughs of 2011