Southwest Quantum Information and Technology

Extending the lifetime of quantum information through error correction

Presenting Author: Robert Schoelkopf, (Yale)

In quantum error correction (QEC) one redundantly encodes an arbitrary bit of quantum information into a larger collection of quantum states, whose symmetry properties allow error syndrome measurements to project the state into a known error space without disturbing the qubit, and enable the recovery from errors via simple operations. Given the considerable overhead inherent in traditional proposals, realizing a QEC protocol at the "break-even" point, which extends the lifetime of information beyond the system's highest quality constituent, remains a difficult and outstanding challenge. Here we demonstrate a fully operational quantum error correction system, based on a logical encoding comprised of superpositions of cat states in a superconducting cavity. This system uses real-time classical feedback to encode, track the naturally occurring errors, decode, and correct, all without the need for post-selection. Using this hardware-efficient approach we reach, for the first time, the break-even point for QEC and preserve quantum information through active means.

(Session 11 : Saturday from 10:45 am - 11:30 am)