IBM’s new quantum computing roadmap provides a detailed and credible plan to build an error-corrected quantum computer before the end of the decade. Its last major roadmap update in May 2022 contained year-by-year development activities from 2019 forward to 2025, with some generalized information about 2026.
I wrote a rather lengthy overview of that roadmap and provided detailed information about IBM’s four new quantum processors in a 2022 Forbes.com article that you can read here.
Full disclosure: IBM has a paid analysis engagement with Moor Insights & Strategy.
Increased Complexity In IBM Quantum Computing
This year, because there is so much foundational work already done plus advanced development work being planned, IBM has created two roadmaps: a development roadmap and an innovation roadmap for hardware and software.
Instead of a small peek at a few future years like what was provided in last year’s roadmap, the two new roadmaps reveal IBM’s quantum computing plans for the next decade.
A larger view of the 2023 IBM roadmaps is available here.
In November, Moor Insights & Strategy CEO and chief analyst Patrick Moorhead and I were invited to IBM Research in Yorktown, New York for a briefing on the new roadmap by Dr. Jay Gambetta, an IBM Fellow and vice president of IBM Quantum.
Historically, Dr. Gambetta positioned IBM as the leader in quantum computing’s first era when quantum emerged as a viable information processing technology. By making quantum computers accessible using the internet during this period, IBM helped stimulate quantum innovation.
Dr. Gambetta believes that three early IBM milestones were foundational for the quantum computing progress that followed. These were:
- Putting quantum computing on the cloud via IBM Quantum Experience in May 2016
- Introducing the Qiskit toolkit as an open-source SDK in March 2017
- Creating the first commercial quantum computer, IBM Quantum System One, in January 2019
2023 And Beyond: An Overview Of The Hardware Roadmap
The next critical areas of focus shown in this year’s roadmap reflect the development of methods and architectures necessary for the eventual error-corrected scaling of quantum machines. Increased qubit fidelity and the capabilities of software and system architectures are important and necessary to take advantage of hardware improvements as they are made each year.
IBM’s hardware roadmap reveals details about how qubits and chip-level innovations can progressively achieve longer coherence times, better error suppression and greater scalability. IBM prioritizes quality, and on a year-by-year basis the roadmap reflects continual improvements as they are made, up until larger error-corrected machines become available in the next decade.
It is obvious from accelerated qubit count, gate count and error correction shown in the roadmap’s later years that IBM is confident that at some point qubits will no longer restrict the scale of quantum computers. It is then that IBM’s focus shifts to building larger systems with the assumption that qubit quality will be there. IBM has already demonstrated it is on track to reduce and control qubit errors.
The next-generation Heron processor is an example of how IBM is improving its qubits. IBM has redesigned the 133-qubit Heron’s quantum controls to minimize noise across the qubits.
The Heron’s modular architecture, which is based on tunable couplers, is different from previous quantum processor architecture. The new architecture connects quantum processors to a common control infrastructure so that data can flow classically and in real time between the QPU and other chips in a multi-chip environment. It also uses a new multi-qubit gate scheme that is both faster and provides higher fidelity.
The Heron is the first IBM chip to use the new architecture that allows multiple processors to be linked using classical couplers to permit classical parallelization. The multi-chip Heron configuration is extensible and based on demand and application requirements.
Modular design, classical coupling and parallelization of quantum hardware are all essential elements in designing future quantum processors. Integrated classical logic in the Heron also reduces system latency.
These qubit techniques are foundational for future advanced error correction schemes that will be used by the more advanced processors in the roadmap.
Also in the roadmap, IBM has established near-term and long-term computational performance targets that are beyond the capability of classical computers. In 2024, IBM is committing to reach levels of quality and circuit depth useful for practical applications across 100 qubits. After that, the roadmap shows steady improvements towards error-corrected logical qubit demonstrations before 2030.
Importance Of Couplers
IBM’s roadmap introduces foundational short- and long-range quantum coupling technologies. Couplers allow qubits to be logically scaled without fabricating larger chips. This accommodates increased input-output density that would otherwise be needed to get more signals in and out of the system.
The coupling scheme requires the same number of wires per qubit, but the couplers stretch out the footprint so that more wires are not crammed into the same physical space.
Short-range couplers use chip-to-chip parallelization to extend IBM’s heavy-hex lattice between multiple chips. This effectively scales qubits by creating a larger but logical chip. Gate speed and gate fidelity of the expanded logical chip do not affect performance because they are about the same as in the individual chips.
Long-range couplers use cables to connect multiple independent modules so that quantum information can be shared between quantum processors. IBM estimates this link will be somewhat slower and lower-fidelity than short-range chip-to-chip coupling; however, programming accommodations can be made to adjust for the differences. One of the benefits of long-range coupling is that it allows modules to be separated for additional input-output space.
Scaling up and enhancing IBM’s hardware also requires extensive software and architectural enhancements. In 2024, IBM will release Qiskit 1.0. This is a significant development because it means that runtime will be managing qubit control and classical interfaces. This will be essential for executing complex quantum circuits efficiently across modular units. Architectural changes will make linking multiple quantum processors feasible, something that’s likely necessary to enable the use of 1,000-plus logical qubits for unprecedented problem sizes.
Qiskit 1.0 will provide a stable and reliable platform for developers to build quantum circuits and applications. This is an important step towards making quantum computing more accessible and practical for a wider range of users.
This roadmap also supports the concept of a quantum-centric supercomputer, a convergence of classical and quantum computers where each technology handles what it does best. The software and system innovations will balance the use of classical resources while maximizing quantum parallelism. This means that quantum computing can be used more efficiently and effectively for a wide range of applications.
IBM Has A Credible Path To Error Correction
Hardware and software developments in the IBM roadmap are intended to make error-corrected quantum computing possible in 2029. IBM has mapped out a sequential and logical path that creates a modular, error-corrected architecture. IBM is currently working to further develop low-density parity check, a promising software error-correction code.
On the roadmap, four years of error-mitigated Flamingo processors grow from 5,000 gates in 2025 to 15,000 gates in 2028 using multi-chip linkage to establish communications between quantum processors. Unique error-correction protocols tailored for 2-D nearest-neighbor qubit arrays are simulated and verified.
In 2026, logical memory and operations in the Kookaburra processor demonstrate that large-scale noise suppression is possible. That noise suppression, combined with steady increases in circuit depth and qubit counts beginning in 2028 with the Starling processor, produces error-corrected accurate outputs beyond what is possible with classical verification.
An Aggressive Path Forward For Quantum Computing
In sum, IBM has created an aggressive decade-long roadmap that leads to solving our ultimate quantum challenge of error correction. The new roadmap reflects IBM’s plan to create a new family of quantum processors, software and services that will lead to the realization of the next generation of supercomputers—a quantum-centric supercomputer. The combined resources of quantum processors, CPUs and GPUs are expected to solve some of the world’s most challenging computational problems.
All of the IBM roadmap developments and plans ultimately converge on 2033 in the form of 2,000 qubits and a billion quantum gates. IBM realizes it will also require education and enabling tools to support building its planned quantum systems. The decade-long plan will likely create an ecosystem that includes error-corrected quantum computers capable of solving many of our previously intractable real-world challenges.