ESE Fall Seminar – “Quantum error correction: Where we are and where we are heading”

Quantum computers based on superconducting qubits have made tremendous strides in device performance, from improved coherences to lowered single- and two-qubit gate errors, and now feature high-fidelity mid-circuit measurements with feedforward. In this talk, I will introduce our fleet of devices that we have developed and deployed at IBM and discuss our work studying quantum error correction on these devices. I will describe some of the encoding, syndrome extraction, and decoding operations that can be tailored to the heavy-hexagon topology, an arrangement that reduces lattice connectivity, in order to mitigate cross-talk between fixed-frequency transmon qubits. Beyond logical memory demonstration on d=2 and 3 codes, I will also discuss our recent results on encoding a magic state with beyond break-even fidelity. Finally, I will briefly introduce our latest finding that enables high-threshold fault-tolerant quantum memory with far fewer qubits compared to a more common surface code architecture.