Quantum Weirdness

Over at Cosmic Variance, Sean Carroll explains a recent paper in Nature whereby the authors were able to find the answer to a problem without actually doing the calculation. The author (Onur Hosten) calls it "counterfactual" quantum computation: "a way of probing the outcome of an event by looking at situations in which it didn't actually happen."

It's fairly mind boggling (even by quantum mechanics standards), but Sean does a heroic job to simplify it. As a tease, he uses steak, salad, and a puppy. Click here to give it a read, especially if you're in the mood to be confused.