In modern computers, information is processed using bits. Quantum computers, however, work with qubits (quantum bits) and aim to carry out calculations which would be too demanding for today’s computers. Theoretical physicists at the Peter Grünberg Institute are looking for ways to establish the practical implementation of quantum information processing. The figure shows a detail from a two-dimensional integrated circuit component for error-tolerant quantum computing. The qubits are coloured green in the illustration.