For 30 years, researchers have pursued the universal quantum computer, a device that could solve any computational problem, with varying degrees of success. Now, a team in California and Spain has made an experimental prototype of such a device that can solve a wide range of problems in fields such as chemistry and physics, and has the potential to be scaled up to larger systems. Both IBM and a Canadian company called D-Wave have created functioning quantum computers using different approaches. But their devices are not easily scalable to the many quantum bits (qubits) needed for solving problems that classical computers cannot. The Google prototype combines the two main approaches to quantum computing. One approach constructs the computer’s digital circuits using qubits in particular arrangements geared to solve a specific problem. This is analogous to a tailor-made digital circuit in a conventional microprocessor made from classical bits. Much of quantum computing theory is based on this approach, which includes methods for correcting errors that might otherwise derail a calculation. So far, practical implementations have been possible only with a handful of qubits. Read more at http://www.nature.com/news/google-moves-closer-to-a-universal-quantum-computer-1.20032