Quantum computers have shown astonishing promise in recent years, with companies from IBM to Google building increasingly powerful machines that are fundamentally expected in many areas, from encryption to medical research.
Quibits – quantum bits that simultaneously occupy a superposition of both 1 and 0 – are the building blocks of quantum machines. But today’s most powerful quantum computers are wildly inefficient due to a phenomenon called “quantum error.” This affects more than 1,000 qubits for each individual, unaffected ‘logical’ quibit.
Now French startup Alice & Bob are testing a new kind of quibt designed to resist quantum errors – by taking a leaf from the original Shrodinger’s Cat experiment on which the theory of quantum superposition is based.
Investing in the power of ‘cat state’ qubits
Instead of coding qubits using different energy levels, for example, Alice & Bob’s strategy involves creating two diametrically opposed states – like the state of life or death experienced by the aforementioned cat. Specifically, they used superconducting microwave resonators that fluctuate between two oscillating states.
The researchers say that using a quantum computer to break the RSA-2048 encryption would require roughly 22 million normal quibits, but only 350,000 of the ‘cat state’ qubits. And for each logical qubit, Alice and Bob would only need 40 quibits. That’s the powerful nature of this research: Amazon has also started working on its own “cat state” quibits.
“When we first heard that Amazon was working on cat qubits, our first reaction as a young startup was obviously to sweat,” Peronnin said. the Institute of Electronic Engineering (IEEE) Spectrum. publication.
“But then we slept on it and realized it might have been the best thing that could have happened to us. We don’t compete about who will win; it’s cat qubits versus the rest of the possible technologies, so for us it’s a great external validation.”
These ‘cat states’ are very resistant to bit-flip, which means that the state of a qubit changes from 1 to 0, or vice versa. However, they are often more vulnerable to phase flip, where quibits alternate between one of two opposing phases, but the researchers said one type of error is easier to fix than two.
The company hopes to create a 14-qubit system by the end of 2023, but the startup will need another six months to calibrate it, so look for more information soon.