On Thursday, the startup IonQ announced that the next generation of its ion-trap quantum computer was ready for use. The new machine marks a major jump for the company, going from 11 qubits up to 32. While this still trails the offerings of companies that are using superconducting qubits, the high fidelity of the trapped ions makes them far less prone to errors and far easier to link into complex configurations. So, by at least one measure of performance, this is the most powerful quantum computer yet made.
Perhaps more significantly, IonQ’s CEO told Ars that it expects to be able to double the number of qubits every eight months for the next few years, meaning its hardware should consistently outperform classical computers within two years.
IonQ isn’t the only company that’s working with trapped ions; Honeywell introduced a quantum computer based on the technology earlier this year. You can read that earlier coverage for more details, but we’ll summarize the reasoning behind this technology here.
Superconducting qubits—used by companies like Google, IBM, and Rigetti—are made using standard fabrication technologies and so are expected to benefit from further progress driven by the semiconductor industry. But as manufactured devices, they are neither perfect nor perfectly identical. As a result, their developers have had to find ways to work around a relatively high error rate and some qubit-to-qubit variability. While these issues have been improved, they’re very unlikely to ever go away. (There are other potential issues, such as inter-device interference and wiring complications, but we’ll set those aside for now.)
The fundamental unit of a trapped-ion qubit, by contrast, is an atom, and all atoms of a given isotope are functionally equivalent and, quite obviously, don’t suffer from manufacturing