Researchers from Paris-based firm Alice & Bob have launched a white paper revealing a roadmap to growing fault-less quantum computer systems by 2030. Step one within the roadmap is the creation of a cat qubit, a particular kind of qubit impressed by the well-known thought experiment Schrödinger’s cat.
The crew at Alice & Bob claims they’ve already developed cat qubits, which provide a number of benefits over standard qubits. As an illustration, whereas common qubits exhibit solely a single superposition, cat qubits can exist in double superposition. Qubits with double superposition is not going to solely enhance fault tolerance but in addition result in enhanced computing energy and algorithm effectivity.
Understanding cat qubit and its deserves
Cat qubits are impressed by Schrödinger’s cat as they use the thought of superposition—an idea the place one thing can exist in two reverse states on the similar time.
In Schrödinger’s thought experiment, a cat inside a field is each alive and lifeless on the similar time till somebody seems contained in the field. Equally, cat qubits symbolize two reverse quantum states on the similar time, identical to the cat’s superposition of alive and lifeless.
Nonetheless, common qubits additionally exhibit superposition as 0 and 1, however what makes cat qubits special is that As a substitute of a easy 0 and 1, the superposition includes two massive, distinct quantum states, like two completely different phases of sunshine or two reverse currents in a circuit.
They provide larger stability over common qubits. Furthermore, cat qubits don’t lose their properties simply underneath the affect of exterior environmental components. This implies they’re extra dependable in relation to storing and processing data.
Probably the most frequent issues quantum programs face is bit-flip errors, which come up when a qubit’s state by chance modifications from 0 to 1 or from 1 to 0. It’s like a light-weight change flipping on or off when it shouldn’t. Correcting bit-flip errors is a crucial side of attaining fault-tolerant quantum computing.
“To create a cat qubit and shield its data from bit-flip errors, we use a so-called coherent state of sunshine (photons) in a superconducting chip,” the white paper stated. This enables cat qubits to simplify quantum error correction by lowering the issue from two dimensions to 1, driving bit-flips to the brink of extinction.
“If we do a side-by-side comparability, we see that our cat qubits shield data from bit-flip errors many tens of 1000’s of occasions longer than different superconducting qubits. we’re nearly eliminating them completely,” the Alice & Bob crew stated.
What’s subsequent within the framework?
Whereas cat qubits provide a number of benefits, they alone aren’t sufficient to attain fault-tolerant quantum computing. This is the reason growing cat qubits is simply step one in Alice & Bob’s framework.
The subsequent step could be to construct a logical qubit that comes with a quantum error correction code. Whereas bodily qubits are prone to noise and errors, logical qubits are designed to be extra steady and fault-tolerant.
As soon as that is achieved, they are going to develop quantum circuits, and logical gates with real-time error correction. All these elements will then be used to create a strong quantum processing unit (QPU) able to performing complicated quantum computations.
Whereas the bits in a classical pc fail at a price of 1 in one million, presently qubits fail at a price of 1 in a thousand. It’s essential to considerably enhance the qubit price to make quantum computers feasible. Hopefully, the framework will obtain this objective and spark a brand new thrilling quantum period.
You possibly can learn the white paper from Alice & Bob here.
