IBM builds prototype quantum computing chip
DOI: 10.1063/PT.5.028839
MIT Technology Review : A superconducting computer chip developed by IBM is the first to feature an arrangement of qubits in a square lattice. Whereas previous superconducting qubits could operate together only when arranged in a line, IBM’s prototype chip features four qubits placed in a two-by-two array. One problem that besets qubits in general is that they are prone to errors. The advantage of the array over the linear pattern is that each of the two pairs of qubits can work together to detect both kinds of quantum errors simultaneously: bit flip, when a qubit flips from a 0 to a 1 or vice versa, and phase flip, when the relative sign between 0 and 1 can become inverted from a plus to a minus or vice versa. The chip represents a stepping stone toward the construction of larger lattices, which will involve even more challenges.