It’s been the fashion among quantum skeptics, but also some policy-makers, to talk about the Age of Quantum as if it’s a technological world off in the distant future—if indeed it’s realized at all. Trying to control large numbers of entangled qubits for computing purposes is too difficult, they say; it’ll be years or decades before we advance from the 53 qubits with Google’s
In fact, a range of quantum computing companies, both large and midsize, are proving the naysayers wrong. The quantum revolution is here, thanks to the development of hybrid systems that integrate the advantages of both quantum computing in solving highly complex problems, and classical computing with its flexibility and accessibility. As our forthcoming QAI
A hybrid quantum computing system is one that combines elements of quantum computing, especially the use of quantum bits or qubits for processing, and classic computers as we know them and they already exist. Working together, quantum and classical can perform functions that are difficult or impossible for a classical computer, even supercomputers, to do alone—while allowing users to read out the results of quantum computation via their classical systems.
A typical model is one where the classical computing platform includes high-level applications programming and HMI functions sitting at one end of the system, and the qubits in the quantum computer sitting at the other. In between control processors provide the vital link making hybridization possible, one operating at room temperature to link to the classical computer and one at cryogenic temperatures to monitor the qubits.
While the quantum computer handles the hard problems, the classical systems take care of everything else — from getting user data and communicating with servers, to displaying results.
These hybrids are going to be the means by which non-quantum users have access to quantum capability, primarily through the cloud. Building and designing the systems that facilitate that interface, then, aren’t temporary fixes. They are foundational to the future of the adoption of quantum technology and give businesses and users—including government—the best of both worlds.
The first company to recognize this possibility was Canada-based D-Wave Systems, Inc. Founded in 1999, it was in 2011 that D-Wave announced D-Wave One as "the world's first commercially available quantum computer", which used a 128-qubit chip set to do the calculations, then used a classical system to read the results generated by the qubits in their lowest energy states—unlike full-scale quantum computers like Google or Microsoft’s
At first quantum purists pooh-poohed the D-Wave approach. But over the last decade D-Wave has gone from strength to strength, solving a range of optimization and modeling problems for clients in manufacturing, logistics, and pharmaceuticals around the world, while increasing the number of qubits in play from the D-Wave 2000Q released in January 2017 with 2048 qubits, to the Advantage in 2020 with 5640 qubits. Last year pharmaceutical giant GlaxoSmithKline
No worries, now IBM is getting into the hybrid business, along with Microsoft. They are recognizing that hybrid systems using hybrid quantum-classical algorithms are going to be the best way to get their regular customers to rely on their quantum computing business, now and in the future.
Another company that has discovered this truth is IonQ, which uses a different model for its quantum computing—using ions of atomic particles to store qubits inside an electromagnetic field—and which is getting into the hybrid algorithm business in a big way.
According to Matthew Keesan, IonQ’s VP of Product Development, “There are lots of things that classical computers are better, or faster at, especially with our current generations of hardware. By letting the quantum computer do what it’s good at, and the classical computer do what it’s good at, you can get more out of both.”
The company that’s led the way in systems architecture to support hybrid computation is Rigetti Computing. Because quantum algorithms require quantum and classical computers to work closely together, the interface between the two must be efficient and fast. Rigetti's system architecture maximizes the computation performance of the combined systems while also making them available over the cloud. Recently the company announced it had arranged to integrate Rigetti Quantum Processing Units (QPUs) with Ampere Altra Max cloud-based processors to create a hybrid computing environment that can be integrated with machine learning applications. “Our partnership with Ampere will build on years of pioneering innovation in hybrid quantum-classical computing at Rigetti,” its founder Chad Rigetti explained. “Together, we’re focused on building the most powerful cloud computers and enabling customers to solve many of the world’s most important and pressing problems.”
So while companies like Rigetti and D-Wave and IonQ have long recognized the reality of quantum hybrid systems-and with IBM and Microsoft coming around as well— it’s also imperative that this reality guide our national quantum policy.
Instead of treating hybridization as a temporary phase or “bridge” to full-scale quantum computing and related uses of quantum technology, it’s time to see it as a key factor in the development and deployment of quantum information science generally. Hybridization will be a key factor in speeding up the timeline for the advent of the Quantum Age, both for creators and users—including in the use of quantum computers for national security purposes.
Classical digital computers are never going to go away. Quantum computers are never going to realize their full potential without them, either. It’s time to think of the Quantum Age as the Hybrid Age, and adjust our national quantum strategy accordingly.
