Hardware-efficient autonomous quantum memory protection. Repeated quantum error correction on a continuously encoded qubit by real-time feedback. Detecting bit-flip errors in a logical qubit using stabilizer measurements.
CORRECTABLE ERROR QUANTUM ERROR CORRECTION CODE
Demonstration of a quantum error detection code using a square lattice of four superconducting qubits.
State preservation by repetitive error detection in a superconducting quantum circuit. Quantum computations on a topologically encoded qubit. Universal control and error correction in multi-qubit spin registers in diamond. H., Cramer, J., van der Sar, T., Dobrovitski, V. Quantum error correction in a solid-state hybrid spin register. Realization of three-qubit quantum error correction with superconducting circuits. Experimental repetitive quantum error correction.
Superconducting circuits for quantum information: an outlook. Surface codes: towards practical large-scale quantum computation. An introduction to quantum error correction and fault-tolerant quantum computation. Multiple particle interference and quantum error correction. Scheme for reducing decoherence in quantum computer memory. Quantum Computation And Quantum Information (Cambridge University Press, Cambridge, 2000). We also perform a Ramsey experiment on the corrected logical qubit, reporting coherence twice as long as for the uncorrected case. The corrected logical qubit has a lifetime 2.8 times longer than that of its uncorrected counterpart.
CORRECTABLE ERROR QUANTUM ERROR CORRECTION FULL
This is achieved while simultaneously maintaining full control of the single logical qubit, including encoding, decoding and a high-fidelity universal quantum gate set with 97% average process fidelity. Here, we experimentally demonstrate repetitive QEC approaching the break-even point of a single logical qubit encoded in a hybrid system consisting of a superconducting circuit and a bosonic cavity using a binomial bosonic code. QEC that reaches the break-even point and single logical-qubit operations have been demonstrated using the bosonic cat code. Logical operations are challenging, owing to the necessary non-local operations at the physical level, making bosonic logical qubits that rely on higher Fock states of a single oscillator attractive, given their hardware efficiency. Logical qubit encoding and quantum error correction (QEC) protocols have been experimentally demonstrated in various physical systems with multiple physical qubits, generally without reaching the break-even point, at which the lifetime of the quantum information exceeds that of the single best physical qubit within the logical qubit.