Quantum advantage describes the moment a quantum computer solves a particular problem faster, or with fewer resources, than the best classical computer could. The word is used in two related ways. It can mark the threshold point itself, and it can describe machines capable of a significant speedup over classical methods, especially when that speedup is practically useful.
A distinction is often drawn between a narrow demonstration and a useful one. Early experiments have shown a quantum processor completing a contrived task that would take a classical supercomputer an impractically long time, but such tasks have little real-world value. The more meaningful milestone is practical quantum advantage, where the problem being solved matters to industry or science, in areas such as materials discovery, chemistry, or optimisation.
Reaching a durable, useful quantum advantage is widely expected to require fault-tolerant quantum computing, and therefore very large numbers of high-quality qubits. This is why Quantum Motion concentrates on the scalability of silicon spin qubits, since the route to a lasting advantage runs through building processors far larger than today’s prototypes.