QUANTUM computing for the masses could come a step closer if tests prove successful on a prototype chip designed to process more quantum data than any previous device.
Quantum computers have the potential to be vastly more powerful than conventional machines because they exploit the rules of quantum mechanics to perform many calculations in parallel. They are difficult to build, however, because quantum information is easily destroyed. The most powerful machines to date can cope with only a handful of quantum bits, or qubits, making them little more capable than a hand-held calculator.
In contrast, the prototype chip built by D-Wave Systems in Burnaby, British Columbia, Canada, is designed to handle 128 qubits of information. The data is stored in 128 superconducting niobium loops as either a clockwise or an anticlockwise current, representing a 0 or a 1, or as a qubit with both currents at the same time in a quantum superposition. When the information needs to be processed, the individual qubits are manipulated by a magnetic field. To make the entire chip superconduct so that the currents can flow indefinitely without dissipating heat, it is cooled to 0.01 °C above absolute zero.
Because superconducting circuits are relatively large, they are easier to manufacture than other types of quantum devices, which manipulate single electrons or photons and so need to be much smaller. “It can be built using standard semiconductor approaches,” says Geordie Rose, chief technology officer of D-Wave. In addition, the method of computation, called adiabatic computing, does not use logic gates, further simplifying the design.