“The Controlled-NOT (CNOT) gate we demonstrate is the basic building block of quantum logic, since in combination with one qubit gates it can be used to perform any quantum operation,” say ...

This is demonstrated succinctly by [Davide ‘dakk’ Gessa] with 200 lines of BASIC code on a Commodore 64 (GitHub), implementing a range of quantum gates. Much like a transistor in classical ...

While many challenges remain, being able to perform basic gate operations with errors occurring below this threshold, satisfies an important condition for future large-scale quantum computation.