Nature: Over the past three decades, as the components that make up integrated circuits have been made smaller and smaller, the power of computer chips has grown exponentially, even as their cost has fallen drastically. But sooner rather than later — by around 2020, according to one estimate1 — the scaling-down process will become difficult to maintain. The energy required to represent a bit of information will become larger than the heat that can be carried away from a tiny circuit element; what's more, as devices approach the size of atoms, quantum-physical phenomena will become important, changing even the ground rules of how bits are processed. Writing in Applied Physics Letters4, Nishiguchi et al. detail what might be one way to circumvent, and even exploit, these issues. They describe a circuit that allows them to perform the computing operation of pattern matching by harnessing the stochastic, quantum-mechanical tunnelling of single electrons into a transistor