If you are a retrocomputer fan, you might remember when serial ports were a few hundred baud and busses ran at a few megahertz at the most. Today, of course, we have buses and fabric that can run at tremendous speeds. Quantum computing, though, has to start from scratch. One major problem is that jockeying quantum states around for any distance is difficult and slow. Part of it is that qubits decay rapidly, so you don’t have much time. They are also generally susceptible to noise and perturbation by outside forces. So many quantum machines today are limited by how much they can cram on one chip since there isn’t a good way to connect to another chip. The University of Sussex thinks it has improved the outlook for quantum interconnects with a technique they claim can move qubits around at nearly 2,500 links per second.

The technique, called UQ Connect, uses electric field links to connect multiple chips using trapped ions for qubits. If you want to read the actual paper, you can find it in Nature Communications.

Like most of quantum computing, the transport mechanism isn’t perfect. But they did manage a 99.99993% success rate. That’s better than some modems we’ve used. The motivation is to allow very large-scale quantum computers to exist. In the paper, they use an example of simulating a particular molecule important to agriculture. The simulation could have real-world benefits but would require a million qubits. Using current technology, the paper explains, a single quantum chip could hold around 2,600 qubits. To assemble a million would require interconnecting many chips, something that hasn’t been feasible without UQ Connect.

The technology reminds us of radio, where electrodes on each module align but don’t touch. The distance in the test, though, wasn’t very large, only 648 μm so you still won’t have a lot of room to pack in modules. But it is an interesting first step and one can imagine a fabric of quantum chips, with each chip edge connecting to other modules.