Turning on quantum memory for superconducting computers on demand

Superconducting quantum processors are fast but forget quickly; rare-earth spin ensembles remember longer but are hard to connect. By driving a Josephson circuit with a parametric pump, the team switches on several MHz of coupling between the two on demand — strong enough for faithful state transfer. This tunable bridge could give superconducting computers access to spin-based memories with coherence times far exceeding anything the chips achieve alone.