Quantum computing companies have fallen into two camps

Most quantum computing companies, including IBM and Google, want to implement applications early in the development of quantum computing, that is, use NISQ (Noisy Intermediate Scale Quantum) computers to perform some simple tasks, and these companies are currently actively conducting proof-of-concept activities.

But there is another faction in the rivers and lakes. PsiQuantum, a Silicon Valley quantum computing company established in 2016, has only moved toward one goal since its establishment, that is, skipping the NISQ stage and directly realizing a million-qubit fault-tolerant quantum computer (FTQC). The company has raised a total of $665 million in a desperate bet on photon-based quantum computers.

Recently PsiQ has re-emphasized that NISQ is not a good choice. Peter Shadbolt, one of the company's founders and current chief scientific officer, is blunt that the current focus on the NISQ computer is an interesting but ultimately wrong path [1].

No quantum computing company has opted for the same strategy as PsiQ before, but now semiconductor giant Intel appears to be joining the bandwagon. The Quantum Computing Report learned from the APS March meeting that Intel believes that useful quantum computing is still a long way off, and they do not plan to offer products for NISQ applications [2].

Two camps both have their advantages and disadvantages

Peter Shadbolt believes that the NISQ system does not provide very good service. "Traditional supercomputers are already very good," he said. "You have to do some step changes, you can't go 5, 10, 20, 50 qubits incrementally to a million. It's not a good strategy. But it would also be inaccurate to say we plan to jump from 0 to 1 million. We are building a whole set of larger and larger systems. These systems allow us to validate control electronics, system integration, cryogenics, networking, etc. But we are not spending Time and effort, trying to dress them up as what they are not. We don't have to take these things and try to extract computational value from things that don't have any computational value. Desperately extract computation. We can use these intermediate systems (NISQ) for ourselves learning and development.”

Peter Shadbolt, co-founder and current chief scientific officer of PsiQ

Shadbolt explained, "If you program a NISQ computer, you'll quickly get bogged down in hardware. You're trying to find shortcuts to the fact that you have so few gates at your disposal. So programming for a NISQ computer is a lot of fun. , stimulating intellectual activity, I've done it myself, but it quickly becomes a little bit isolating and you have to pick a winner. Now that's changing, people are starting to program error-correcting quantum computers instead of NISQ computers. It's a welcome change, and the whole field is changing."

Unlike NISQ's difficulty of programming, "With fault tolerance, you can start programming in a set of fault tolerance gates that are hardware independent, and it's much simpler to process. This means that the optimizations you make on the algorithm in the fault tolerance mechanism are In many cases it's the opposite of the optimizations you do in the NISQ mechanism," he said.

Unlike PsiQ, which is staunchly against NISQ, Intel isn't so aggressive. They believe that the development of quantum technology is still in very early stages and do not intend to provide cloud access to end users anytime soon. The business model for commercial quantum products, mainly from Intel, has not yet been fully determined. They have many options, including selling individual chips, supplying complete quantum computers to OEMs, partnering with cloud providers, or even becoming a cloud provider themselves. But there is still a lot of technical development work to be done, and the quantum ecosystem is sure to change dramatically in the years to come. So it's better for them to keep the option in the short term.

Intel is producing silicon spin qubits on 300mm wafers.

In a sense, Microsoft has adopted a similar strategy. They have been studying topological qubits for more than ten years. In theory, this technology is extremely stable, so the topological quantum computer itself is a fault-tolerant quantum computer. Although Microsoft has often announced new breakthroughs in recent years, this kind of machine is also short-term. impossible. Perhaps because of the same vision, Microsoft chose to invest in PsiQ.

While PsiQ says there are too many benefits to skipping the NISQ stage, there are risks to this strategy.

There are many ways to implement quantum computer hardware, including IBM, Google's superconducting circuits, Honeywell, IonQ's trapped ions, Microsoft's topological qubits, Intel's semiconductor quantum dots, PsiQ, Xanadu's photons, and Pasqal , QuEra's neutral atoms, etc.

At present, these technical routes have not yet opened the gap, but if a technology with obvious advantages emerges in the next few years, or the technology chosen by the company itself encounters major setbacks in the future, since a large amount of money has been invested, it may not be realistic to think about turning around. , especially for startups.

Another risk is that once a quantum computer is launched by a company that chooses to skip the NISQ stage, will there be software and algorithms on the market for such a machine? That's why companies interested in quantum computing start preparing now, as they may lose their competitive advantage if they wait until a fault-tolerant general-purpose quantum computer is implemented to start developing applications. So the benefit of NISQ is that the application can be iterated over as the hardware evolves.

PsiQ is also well aware of the downsides of working behind closed doors, so while they do not offer quantum computing services to the public, they are also actively conducting joint research with related companies, such as the recently announced partnership with Mercedes-Benz.

At present, most quantum computing companies that choose incremental development are developing hardware-independent software and algorithms. No matter which technology route wins in the future, these companies will all benefit, but the difference is big and small, which is equivalent to a hedge. For example, even if Microsoft can never develop a topological quantum computer, it can still get a piece of the pie by virtue of its layout in software development and cloud platform services. By contrast, PsiQ may be an all-or-nothing gamble.

But we can't tell which is the better strategy, after all what will happen in the future, who knows?

China chooses to lay eggs along the way

Let's look at the situation in China again. In recent years, the saying of "laying eggs along the way" has become popular in China's science and technology field, and quantum information technology is no exception. This is actually the same strategy as IBM and Google.

Professor Lu Chaoyang of the University of Science and Technology of China pointed out that the field of quantum computing is currently in the rising period of the bubble period. He believes that the next fastest "egg" may be the NISQ application. The most promising near-term applications of quantum computing should be the study of quantum physical systems themselves—many-body problems, quantum chemistry, and quantum materials [3].

According to the photon box, around the quantum chip developed by the "Zuchongzhi" research team, Guodun Quantum and the University of Science and Technology of China have developed the superconducting quantum computing control system ez-Q Engine, and the Institute of Software of the Chinese Academy of Sciences and Arc Quantum have developed quantum computing programming software. isQ-Core, together with a joint team from National University of Defense Technology and East China Normal University, developed the "Quingo" quantum programming language.

Zu Chongzhi No. 2 quantum computing chip

So far, with the efforts of various teams, the quantum chip developed by the research team of "Zu Chongzhi" has completed the construction of the basic layer and the development layer, laying a solid foundation for the practical application of quantum computing.

In addition, Benyuan Quantum Computing Company has completed a full-stack layout, ranging from hardware, software to cloud platforms, and has taken the lead in building a quantum computing industry alliance. Information security has achieved certain results.

It can be said that almost all research groups in China have chosen an incremental development model, which to a certain extent represents the Chinese philosophy of the mean.

Finally, leave an interactive topic: For the two current trends in the field of quantum computing, incremental vs step, which method do you think is better? Welcome to leave a message in the comment area!

Link:

[1]https://www.hpcwire.com/2022/04/21/psiquantums-path-to-1-million-qubits-by-the-middle-of-the-decade/

[2] https://quantumcomputingreport.com/a-look-at-intels-quantum-computing-efforts/

[3] https://mp.weixin.qq.com/s/PtaLHlXEsJmF6vc4C6oyYw