Physics World had a news story about developments in quantum computation, covering two new papers in Nature:
- Coupling superconducting qubits via a cavity bus from the groups of Steve Girvin and Rob Schoelkopf at Yale, also described in this press release.
- Coherent quantum state storage and transfer between two phase qubits via a resonant cavity by a group at NIST at Boulder, also described in this press release.
These are completely independent experiments, as far as I know, but they’re doing essentially the same thing: They’re demonstrated the transfer of quantum information between two “qbits” in different places, by means of a coupling into a microwave cavity. Both qbit systems are superconducting junctions (two pieces of superconductor separated by a very thin insulating barrier that electron pairs can tunnel through), though they use two different schemes to encode the actual quantum information.
This is a fairly important step in the development of quantum computers, not so much because it brings us much closer to factoring large numbers (it doesn’t, particularly), but because any realistic quantum information processing system of the future will need to be able to shuffle information from one place to another, either within a complex processing unit, or through some version of what Jeff Kimble calls the “quantum Internet.”
I may try to explain this more thoroughly later, but not through the fog of an antihistamine hangover.