Quantum error correction and universal gate set operation on a binomial bosonic logical qubit

By Ling Hu, Yuwei Ma, W. Cai, X. Mu, Yuan Xu, Weiting Wang, Yukai Wu, Haiyan Wang, Yipu Song, Chang-Ling Zou and 3 more. Nature Physics, 2018

323 citations recorded by the source corpus.

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. 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. QEC that reaches the break-even point and single logical-qubit operations have been demonstrated using the bosonic cat code. 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. 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. The corrected logical qubit has a lifetime 2.8 times longer than that of its uncorrected counterpart. We also perform a Ramsey experiment on the corrected logical qubit, reporting coherence twice as long as for the uncorrected case. Repeated error correction creates a logical qubit encoded in the hybrid state of a superconducting circuit and a bosonic cavity, which is shown to be fully controllable under a universal single-qubit gate set.

Subfields: Artificial Intelligence, Computational Theory and Mathematics

View Paper: https://www.semanticscholar.org/paper/55ba3f3ff5d731ba817edd8d68bbdafed1f04a6b

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Citations in the corpus

Fault-tolerant bosonic quantum error correction with the surface–Gottesman-Kitaev-Preskill code (2019, background): “All these codes encode a logical qubit in a physical bosonic oscillator mode and have been realized experimentally in circuit QED [9–14] and trapped ion [15–17] systems in the past few years.”
Circuit quantum electrodynamics (2020, background): “…2009), cloud-based devices are accessible, demonstrations of quantum-error correction have approached or reached the so-called break-even point (Hu et al., 2019; Ofek et al., 2016), and devices with several tens of qubits have been operated with claims of quantum supremacy (Arute et al., 2019).”
Engineered dissipation for quantum information science (2022, background): “…can be maintained in steady state via a combination of dissipation and resonant driving, the cat states can be stabilized by appropriate two-photon driving and dissipation 8,131 , in this way, dissipation can be harnessed to actually reduce error rates, beyond just detecting errors for correction.”
Quantum information processing and quantum optics with circuit quantum electrodynamics (2020, background): “There is the need to calibrate the individual qubit and cavity frequencies, and their couplings to one another, to properly control and readout the processor, as well as to null out classical cross-talk and unwanted coherent Hamiltonian dynamics 54,85 .”
Fast universal control of an oscillator with weak dispersive coupling to a qubit (2021, methodology): “For the binomial code, previous experiments have demonstrated logical state preparation using GRAPE, relying on a large coupling χ/2π compared to decoherence rates [2, 6, 12, 13, 37].”