Picture: Alice & Bob.
After an initial fundraising of three million euros, the start-up Alice & Bob is raising 27 million euros to launch, by 2023, its first quantum computer based on “cat qubits”, as reported TechCrunch. This Series A financing round is led by Elaia, Bpifrance – through its Digital Venture fund – and Supernova Invest, with participation from Breega.
Quantum promises immense computing power. On a market estimated at several hundred billion dollars, the start-up Alice & Bob is a flagship of research in France in this field. The company announced in a blog post that it had successfully demonstrated how to correct an error that cripples quantum computers.
In its work, carried out with the team of Zaki Leghtas from the physics laboratory of the Ecole Normale Supérieure (ENS), Alice & Bob showed that its “cat qubits” were effective against “bit-flips”, the one of the two types of recurring errors found in quantum science.
Cat’s qubit fixes errors on its own
Classical computing is subject to the “bit-flip” type error, which exchanges a 0 to 1 or a 1 to 0. This error is also possible in the quantum world, as well as another error called the ” phase-flip”, where a positive qubit becomes negative, and vice versa. This error is related to the decoherence process. These two types of errors are due to the interactions between the qubits and the environment. The whole challenge of the quantum computer is to succeed in isolating a system to avoid errors.
The “cat qubit” is a central concept in Alice & Bob’s work. It is made from superconducting circuits. It is a qubit capable of correcting its errors autonomously without requiring redundancy, the ultimate goal being to build a universal error-free computer.
Alice & Bob wanted to demonstrate that its cat qubit stabilization scheme was “compatible with macroscopic bit-flip times,” writes the startup. Concretely, what does this mean? Alice & Bob says it has increased bit-flip error resilience from a previous all-time high from milliseconds to minutes. It doesn’t seem like much, and yet it makes all the difference. Alice & Bob claims to have succeeded in multiplying the lifetime of quantum bits by a factor of 100,000.
Once the bit-flips have been corrected autonomously, then all that remains is to correct the phase-flips. Théau Peronnin, CEO and co-founder of Alice & Bob, alongside Raphaël Lescanne, told TechCrunch that the next step will be to work on using qubit chat to reduce phase-flips. This funding round should enable Alice & Bob to pursue its ambitious roadmap.