Wiring a New Path to Scalable Quantum Computing

(Phys.org) A new circuit-wiring scheme developed over the last three years by RIKEN’s Superconducting Quantum Electronics Research Team, in collaboration with other institutes, opens the door to scaling up to 100 or more qubits within the next decade.
Last year, Google produced a 53-qubit quantum computer that could perform a specific calculation significantly faster than the world’s fastest supercomputer. Like most of today’s largest quantum computers, this system boasts tens of qubits—the quantum counterparts to bits, which encode information in conventional computers.
To make larger and more useful systems, most of today’s prototypes will have to overcome the challenges of stability and scalability. The latter will require increasing the density of signaling and wiring.
At RIKEN, a superconducting circuit with an element called a Josephson junction is used to create a useful quantum-mechanical effect. In this way, qubits can now be produced reliably and repeatedly with nanofabrication techniques commonly used in the semiconductor industry.
The other major challenge for quantum computers is how to deal with the intrinsic vulnerability of the qubits to fluctuations or noise from outside forces such as temperature. Now, by cooling quantum computers to cryogenic temperatures and creating several other environmental controls, we can maintain coherence for up to 100 microseconds.