Does Willow wow? Caltech, Delft, & others assess chip's below-threshold error correction

Quantum Campus shares the latest in quantum science and technology from university campuses. We publish on Fridays and are always looking for news from researchers across the country. Want to see your work featured? Submit your ideas to the editor.

Beyond breakeven

Google released details of its 105-qubit Willow processor that can reliably error correct more rapidly than it generates errors. The company published in Nature this week and shared a blog post on their work.

In a separate news article, Nature spoke to researchers who were not involved in the development at the University of Science and Technology of China, Delft University, Harvard, and Caltech. Scientific American and New Scientist also had takes — including Daniel Gottesman, a quantum information scientist who helped develop the theory behind error correction decades ago, saying “It's about time we’re finally seeing these demonstrations of fault tolerance.”

Stacking domains in graphene

A team from New York University and Charles University observed the self-assembly of ABA and ABC stacking domains in a three-layer epitaxial graphene system grown on silicon carbide. They used conductive atomic force microscopy in their work.

Creating these stacking domains has historically been an exacting and manual process, making it difficult to scale for industrial applications. These self-assembled ABA/ABC stacking domains could be well-suited to quantum applications, according to NYU, because they can enable behaviors like unconventional quantum Hall effects, superconductivity, and charge density waves.

The team’s findings were published in PNAS.

Chiral superconductors

Quanta published a review of new species of superconductors discovered this year, including twisted bilayer tungsten diselenide and rhombohedral graphene.

The rhombohedral graphene produces a chiral superconductivity that is “phenomenologically different from all other superconductors,” according to MIT’s Long Ju, who leads the graphene team. It also leaves theorists and experimentalists alike scratching their heads and declaring it “uncharted territory.”

All-to-all quantum routing

University of Chicago researchers released a new design for a modular superconducting quantum processor. Using a reconfigurable router as a central hub, any two qubits in the processor can connect and entangle, in contrast to other systems in which qubits can only talk to others physically nearest to them.

“Imagine you have a classical computer that has a motherboard integrating lots of different components, like your CPU or GPU, memory and other elements,” said Xuntao Wu, a PhD candidate in Andrew Cleland’s lab at U of C. “Part of our goal is to transfer this concept to the quantum realm.”

Their work was published in Physical Review X. 

Quickbits

• IBM to launch National Quantum Algorithm Center

• Quantum phase estimation protocols in Physical Review A

• Topological quantum gates in two-dimensional magnet-superconductor hybrid in npj Quantum Materials

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