The latter technique, which effectively doubles the available quantum resources, was invented only last year7.
Part of the IBM team’s gains are the result of measures that reduce errors in the quantum computers. These include error mitigation, in which noise is cancelled out using algorithms similar to those in noise-cancelling headphones, and entanglement forging, which identifies parts of the quantum circuit that can be separated out and simulated on a classical computer without losing quantum information. The latter technique, which effectively doubles the available quantum resources, was invented only last year7.