Quantum computing, which uses the principles of quantum mechanics to solve extremely complex problems, has recently seen significant advances that are making the technology much more practical. The possibility of surpassing today’s computing limitations has become increasingly relevant given the exponentially growing need of resources for generative AI. Realizing solutions to otherwise unsolvable problems has generated interest from companies and significant funding for quantum computing companies.
While pursuing his PhD in physics, Théau Peronnin was part of the quantum-electronics group at École normale supérieure, building the academic foundations for quantum computers. He cofounded Alice & Bob in 2020 to continue that work. The company has raised more than €30 million to date and is home to 80 physicists and engineers working to build the world’s first universal fault-tolerant quantum computer.
McKinsey partner Henning Soller sat down with Peronnin to learn his perspective on the value quantum computers can provide and how companies can prepare for their arrival.
Henning Soller: What’s the inherent advantage of a quantum computer? Where will its impact be most felt?
Théau Peronnin: Quantum will always be paired with classical computing to shape or prepare the data because quantum is only good at a handful of things. But these handful of things happen to have use cases everywhere.
Take AI, for example. On one hand, some believe Moore’s Law, which describes the scaling of compute power, has been slowing down and may plateau at some point. On the other hand, the scale of the infrastructure required to train generative AI models has basically reached global scale; it costs tens to hundreds of millions of dollars to train novel models. But we’re still falling very short of AI achieving human-level intelligence. We’ll need a profound disruption in computing to push it forward. This is what quantum could bring.
People are throwing around a lot of numbers in the hundreds of billions of dollars for the market potential for quantum. What all those numbers have in common is that they are unreasonably large. But they do indicate that there is a great potential for disruption through quantum. You must remember, though, that quantum is not the end goal. The end goal is to change the scale at which we can compute, which can drive better engineering and thereby increase value creation. This is what all the different types of compute—from telecommunications to AI—have been doing for the past 60 years. Quantum offers new breadth in that momentum of generating growth.
Where will that growth happen? It’s a trade-off for companies and industries between how tech savvy and aware they are of what quantum offers and the potential quantum has for them. For example, since the ’90s, financial institutions have understood the level of compute that can generate value for them, even though it’s not very transformative for humankind. In comparison, you have industries for which it could completely change the engineering—from pharmaceuticals to battery design in automotive. The problems that are most suited to quantum all boil down to material chemistry and biology.
Henning Soller: When do you think quantum computing will become a reality?
Théau Peronnin: I believe the signaling milestone for the beginning of quantum is happening now: a machine has been able to escape decoherence. That is, a logical qubit system is correcting its errors and is thereby demonstrating how quantum computing can become a reality. This means that we are now able to build machines that behave as promised. Next, we need to scale them up.
Error correction and managing decoherence will be key aspects from both a technology and a software perspective going forward. We can make major advancements with respect to the underlying technology, but we can also improve the algorithms and possibly even leverage decoherence.
The question is when the hardware will meet the requirements of real-world use cases and generate real-world value. For this, we need to increase the number of qubits, but right now, there’s also a trend of innovating to reduce the required number of qubits. I believe these two trends will converge somewhere between 2027 and 2030.
Henning Soller: What can companies do at this stage to prepare for quantum computers?
Théau Peronnin: Quantum is all about first-mover advantage. If you take, for example, the automotive industry, the first company to be able to leverage novel hardware will be the first one to secure IP [intellectual property] on novel battery design. Once you start looking at quantum that way, you see that it’s going to cost maybe a few million dollars over several years to ramp up a decent team of four to six people internally so a company can expand as soon as it’s ready to move.
But it’s important not to get lost in proofs of concept. Companies should start by doing value calculations and prioritizing use cases. Then companies can carefully consider the trade-off and cost between being too early or too late in quantum.
Théau Peronnin is CEO and cofounder of Alice & Bob. Henning Soller is a partner in McKinsey’s Frankfurt office.
Comments and opinions expressed by interviewees are their own and do not represent or reflect the opinions, policies, or positions of McKinsey & Company or have its endorsement.