Leonardo diCarlo

Protecting a superconducting logical qubit from bit-flip error

QuTech & Kavli Institute of Nanoscience, Delft University of Technology

Safeguarding quantum data against arbitrary errors induced by decoherence and faulty hardware remains an outstanding challenge for all quantum information platforms. Quantum error correction requires a combination of quantum and classical capabilities: discretizing and signaling physical qubit errors through non-demolition quantum parity measurements, and tracking these errors with a classical controller that simultaneously advances computation. I present an implementation of the textbook quantum repetition code protecting one logical qubit (a two-dimensional subspace in a three-qubit Hilbert space) from bit-flip error, realized  with a circuit QED processor with twelve quantum elements  controlled by room-temperature electronics. A discussion of this processor’s performance and limitations motivates a survey of our current efforts to develop a scalable quantum architecture and scalable control electronics for protecting quantum data from arbitrary errors.