Striking a Balance for Quantum Bits

T he hypothesized Majorana bound state is a quasiparticle that scientists think could be a building block of a future quantum computer. It is predicted to be hosted by two quantum dots—semiconducting nanocrystals—separated by a narrow superconducting segment, but this can happen only if the processes coupling the dots are perfectly balanced. Now Tom Dvir at the Delft University of Technology in the Netherlands and his colleagues experimentally balance these processes in a hybrid semiconductor-superconductor system [1]. The experiments show no signs of a Majorana bound state, but the researchers plan to use their findings to develop a method to spot this elusive quasiparticle.