Scientists established in the 1990s that some of a quantum computer’s qubits could be dedicated to correcting those errors, and the years since then have been spent searching for ways to construct physical qubits so that enough “logical” qubits are left over to do useful computing work.
The standard industry thinking has been that a chip will need about a million physical qubits to yield a useful number of logical qubits.
But AWS said it had built a prototype chip that uses only nine physical qubits to yield one working logical qubit, thanks to the use of what is known as a “cat” qubit, so named for physicist Erwin Schrodinger’s famous thought experiment to illustrate principles of quantum mechanics in which an unlucky cat in a box is both dead and alive at the same time.
Oskar Painter, AWS director of quantum hardware, said the AWS approach could one day yield useful computers with only 100,000 qubits rather than a million.
“It should allow us to provide between five and 10 times lower numbers of physical qubits to implement the error correction in a fully scaled machine. So that’s the real benefit,” Painter told Reuters.
Painter said that the current chip was constructed using standard techniques borrowed from the chip industry and a material called tantalum, but that AWS and partners hope to customise those techniques further.
“That’s where I think there’s going to be a huge amount of innovation and that will be the thing that could really reel in timelines for development. If we make improvements at the materials and processing level, this will make the underlying technology just much simpler,” Painter said.
