Watching a gas turn superfluid
Every time you boil water in a kettle, you witness a phenomenon known as a phase transition — water transforms from a liquid to a gas, as you can see from the bubbling water and hissing steam. MIT physicists have now observed a much more elusive phase transition: that from a gas into a superfluid, a state where particles flow without any friction. The MIT work, published last week in the online edition of Science, also sheds light on the superconductivity of electrons in metals, including high-temperature superconductors that have the potential to revolutionize energy efficiency.The researchers, led by MIT assistant professor of physics Martin Zwierlein, carried out their experiment with an isotope of lithium that has an odd number of electrons, protons and neutrons. Such particles are called fermions. In order to become superfluid and flow without friction, fermions need to team up in pairs. This is what happens...