Scientists demonstrate coherent coupling between a quantum dot and a donor atom in silicon

Quantum computers could tackle problems that current supercomputers can’t. Quantum computers rely on quantum bits, or “qubits.” Current computers perform millions of calculations, one after the other. Qubit coupling allows quantum computers to perform them all at the same time. Qubits could store the data that add up to bank accounts and medical records. In an unusual twist, qubits represent data by the binary state of electron spins. Two systems existed to create qubits. Researchers successfully integrated the systems—donor atoms and quantum dots. The new qubits don’t let the spins, and hence the data, degrade. Specifically, the bits demonstrate coherent coupling of the electron spins. This hybrid approach, which has remained elusive until now, exploits the advantages of the two qubit systems.