October 22, 2012 | 4
For years I’ve been thinking and hoping that quantum physics would become the next hacker revolution. DIYers in their basements, garages, and hackerspaces have already pioneered radio communications, PCs, household robots, and cheap 3-D printers—why not quantum entanglement, cryptography, computers, and teleportation? In recent years, physics educators have streamlined quantum experiments to the point where advanced amateurs could do them at home. I’ve tried to encourage the trend by inviting a Sci Am article on how to make a quantum eraser with a laser pointer and, last week, blogging about a particle detector in a plastic party tumbler.
In the latest issue of Make magazine, I learned about an extraordinary book that could do for quantum homebrewers what Popular Electronics magazine did for Jobs and Wozniak in the ’70s. Written by the father-daughter team of David and Shanni Prutchi, Exploring Quantum Physics Through Hands-On Projects takes you from basic particle-wave demonstrations all the way up to quantum random-number generators. The associated website follows up with detailed advice and other projects. Had you asked me a month ago, I would have said that an atomic clock is surely beyond the capacity of even the most dedicated hobbyist. Now I know better.
I happened to be down in Philadelphia, near where the Prutchis live, for a conference two weeks ago, and David (shown above with his other two daughters, Abigail and Hannah—Shanni was still at school) kindly gave me a tour of their basement lab. The first clue that it wasn’t just any suburban house was the radio telescope in the backyard, which Shanni used to map the Milky Way’s hydrogen gas in fifth-grade. The living room tchotchkes included an old Civil Defense radiation meter and blown-glass Crookes tubes. The lab itself, about the size of a one-car garage, is a work of art in its own right, lined with snazzy electronics, such as spectrum analyzers, as well as contraptions out of a Victorian experimental philosophy lab, such as van de Graaf generators. It’s better outfitted than some academic labs I’ve seen, but David modestly insisted they cobbled it together from Home Depot, eBay, and dumpster dives at local high-tech firms. The book offers tips for how to do the same.
More than equipment, though, experimentation requires persistence. Shanni said she shudders at the effort it took to prove quantum spooky action at a distance. The principle is simple (see this video my colleagues and I made); the practice is a different story. For instance, the experiment requires light detectors that are sensitive enough to detect single photons, which means they are also prone to the tiniest sliver of stray light. David and Shanni kept them dark by enclosing the apparatus in a set of nested black boxes, which they had to open and close to make any adjustment—and an experiment of this sort requires a lot of adjustments. “I hated that black box,” Shanni told me. “There were days I didn’t want to do the experiment. It was very frustrating, but it all paid off. We were actually able to disprove local hidden variables—and I’m a high-school senior.”
Photos by George Musser