IBM's new chip integrates the basic devices needed to build a quantum computer, known as qubits, into a 2-D grid.

Boffins currently think one of the best routes to making a practical quantum computer would involve creating grids of hundreds or thousands of qubits working together.

The circuits of IBM's chip are made from metals that become superconducting when cooled to extremely low temperatures. The chip operates at only a fraction of a degree above absolute zero. Which makes it impossible for a cat to get near it.

IBM's chip contains only the simplest grid possible, four qubits in a two-by-two array.

A paper published today details how IBM's chip with four qubits arranged in a square can detect both bit and phase flips. One pair of qubits is checked for errors by the other pair of qubits. One of the pair doing the checking looks for bit flips and the other for phase flips.

The Big Blue team of suits ad to carefully design its new chip to overcome interference problems caused by putting the four qubits so close together. They are already experimenting with a chip that has a grid of eight qubits in a two-by-four rectangle.

Raymond Laflamme, director of the institute for quantum computing at the University of Waterloo, Canada, describes IBM's results as "an important milestone [toward] reliable quantum processors." Tackling errors is one of the field's most important problems. "Quantum computing promises to have many mind-boggling applications, but it is hindered by the fragility of quantum information."