Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 536 (7617), 441-5

Extending the Lifetime of a Quantum Bit With Error Correction in Superconducting Circuits

Extending the Lifetime of a Quantum Bit With Error Correction in Superconducting Circuits

Nissim Ofek et al. Nature.

Abstract

Quantum error correction (QEC) can overcome the errors experienced by qubits and is therefore an essential component of a future quantum computer. To implement QEC, a qubit is redundantly encoded in a higher-dimensional space using quantum states with carefully tailored symmetry properties. Projective measurements of these parity-type observables provide error syndrome information, with which errors can be corrected via simple operations. The 'break-even' point of QEC--at which the lifetime of a qubit exceeds the lifetime of the constituents of the system--has so far remained out of reach. Although previous works have demonstrated elements of QEC, they primarily illustrate the signatures or scaling properties of QEC codes rather than test the capacity of the system to preserve a qubit over time. Here we demonstrate a QEC system that reaches the break-even point by suppressing the natural errors due to energy loss for a qubit logically encoded in superpositions of Schrödinger-cat states of a superconducting resonator. We implement a full QEC protocol by using real-time feedback to encode, monitor naturally occurring errors, decode and correct. As measured by full process tomography, without any post-selection, the corrected qubit lifetime is 320 microseconds, which is longer than the lifetime of any of the parts of the system: 20 times longer than the lifetime of the transmon, about 2.2 times longer than the lifetime of an uncorrected logical encoding and about 1.1 longer than the lifetime of the best physical qubit (the |0〉f and |1〉f Fock states of the resonator). Our results illustrate the benefit of using hardware-efficient qubit encodings rather than traditional QEC schemes. Furthermore, they advance the field of experimental error correction from confirming basic concepts to exploring the metrics that drive system performance and the challenges in realizing a fault-tolerant system.

Similar articles

See all similar articles

Cited by 24 articles

See all "Cited by" articles

References

    1. Phys Rev Lett. 2013 Sep 20;111(12):120501 - PubMed
    1. Nat Commun. 2016 May 05;7:11526 - PubMed
    1. Science. 2013 Mar 8;339(6124):1169-74 - PubMed
    1. Nat Nanotechnol. 2014 Mar;9(3):171-6 - PubMed
    1. Science. 2011 May 27;332(6033):1059-61 - PubMed

Publication types

LinkOut - more resources

Feedback