The end of the year is usually a busy time in the quantum computing arena, as companies often try to announce that they’ve reached major milestones before the year wraps up. This year has been no exception. And while not all of these announcements involve interesting new architectures like the one we looked at recently, they’re a good way to mark progress in the field, and they often involve the sort of smaller, incremental steps needed to push the field forward.
What follows is a quick look at a handful of announcements from the past few weeks that struck us as potentially interesting.
IBM follows through
IBM is one of the companies announcing a brand new architecture this year. That’s not at all a surprise, given that the company promised to do so back in June; this week sees the company confirming that it has built the two processors it said it would earlier in the year. These include one called Loon, which is focused on the architecture that IBM will use to host error-corrected logical qubits. Loon represents two major changes for the company: a shift to nearest-neighbor connections and the addition of long-distance connections.
IBM had previously used what it termed the “heavy hex” architecture, in which alternating qubits were connected to either two or three of their neighbors, forming a set of overlapping hexagonal structures. In Loon, the company is using a square grid, with each qubit having connections to its four closest neighbors. This higher density of connections can enable more efficient use of the qubits during computations. But qubits in Loon have additional long-distance connections to other parts of the chip, which will be needed for the specific type of error correction that IBM has committed to. It’s there to allow users to test out a critical future feature.