IBM Quantum processor types¶
Processor types are named for the general technology qualities that go into builds, consisting of the family and revision. Family (e.g., Falcon) refers to the size and scale of circuits possible on the chip. This is primarily determined by the number of qubits and the connectivity graph. Revisions (e.g., r1) are design variants within a given family, often leading to performance improvements or tradeoffs. Segments are comprised of chip sub-sections, and are defined within a given family. For instance, segment H of a Falcon consists of seven qubits arranged as seen in the illustration below. Segment H on a Hummingbird, if implemented, could be entirely different.
Using a heavy-hexagonal qubit layout, the Hummingbird family allows up to 65 qubits.
r2 (August 2020) Released in 3Q 2020, this revision contains 65 qubits. Improvements previously demonstrated on Falcons, like readout multiplexing, space-efficient qubit-qubit couplers, and flip-chip technology enhanced the capabilities of the Hummingbird family and led to a scalable 65Q design.
r1 (October 2019) This revision is the first attempt at supporting a large (>50) number of qubits on a chip.
The Falcon family of devices offers a valuable platform for medium-scale circuits, and also serves as a valuable platform for demonstrating performance and scalability improvements before they’re pushed onto the larger devices.
r5.11 (January 2021) In addition to the filtering in r5.10, design improvements target speed-ups in qubit state readout. An essential requirement for quantum error correction demonstrations is fast readout. To enable this, the paradoxical requirements of stronger readout coupling yet protection from qubit relaxation is accomplished with advanced filtering techniques and fine tuning of various components’ couplings on-chip. This revision, combined with the latest in control electronics, enables mid-circuit measurements.
r5.10 (December 2020) This revision pioneered advanced on-chip filtering techniques that eventually led to the faster qubit state readout in r5.11. The filters reduce qubit relaxation and preserve lifetime. Additionally, space-saving “direct-couplers” are used to couple qubits together, essential for scaling to larger bird families.
r4 (April 2020) Adding to the capabilities of r1, the r4 is the first revision in the large birds to deploy multiplexed readout. Previous designs required an independent signal pathway on the chip, as well as in the dilution refrigerator and control electronics for qubit state readout.
r1 (February 2020) The first generation of the Falcon family, r1 is a 28Q offering independent readout, contrasting to the multiplexed configurations in the other revisions. The flip-chip technology allowed scaling to a larger number of qubits. The heavy-hex connectivity graph is employed for the first time here, optimal for our two-qubit gate of choice, cross-resonance.
The Canary family comprises small designs containing anywhere from 5 to 16 qubits.
Up to 16 qubits
Optimized 2D lattice: All of the qubits and readout resonators are on the same layer
r1.3 (December 2019) A stripped-down offering containing only a single qubit.
r1.1 (May 2017) Using the similar design processes to r1, r1.1 extends the design to include 16 qubits.
r1 (January 2017) Initial 5Q design with resonators and qubits all on a single lithography layer.