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Abstract |
Superconducting electronic circuits are ideally suited for studying quantum
physics and its applications. Since complex circuits containing hundreds or
thousands of elements can be designed, fabricated, and operated with relative
ease, they are one of the prime contenders for realizing quantum computers.
Currently, both academic and industrial labs vigorously pursue the realization
of universal fault-tolerant quantum computers. However, building systems which
can address commercially relevant computational problems continues to require
significant conceptual and technological progress.
For fault-tolerant operation quantum computers must correct errors occurring due
to unavoidable decoherence and limited control accuracy. Here, we demonstrate
quantum error correction using the surface code, which is known for its
exceptionally high tolerance to errors. Using 17 physical qubits in a
superconducting circuit we encode quantum information in a distance-three
logical qubit building up on our recent distance-two error detection experiments
[1]. In an error correction cycle taking only 1.1 µs, we demonstrate the
preservation of four cardinal states of the logical qubit. Repeatedly executing
the cycle, we measure and decode both bit- and phase-flip error syndromes using
a minimum-weight perfect-matching algorithm in an error-model-free approach and
apply corrections in postprocessing. We find a low logical error probability of
3 % per cycle [2].
The measured characteristics of our device agree well with a numerical model.
Our demonstration of repeated, fast, and high-performance quantum error
correction cycles, together with recent advances in ion traps, support our
understanding that fault-tolerant quantum computation will be practically
realizable.
[1] C. Kraglund Andersen et al., Nature Physics 16, 875–880 (2020)
[2] S. Krinner, N. Lacroix et al., Nature 605, 669–674 (2022)
* Work done in collaboration with Sebastian Krinner, Nathan Lacroix, Ants Remm,
Agustin Di Paolo, Elie Genois, Catherine Leroux, Christoph Hellings, Stefania
Lazar, Francois Swiadek, Johannes Herrmann, Graham J. Norris, Christian Kraglund
Andersen, Markus Müller, Alexandre Blais, Christopher Eichler, and Andreas
Wallraff |
