Encoded Qubit Alive (eQual) with Trapped Ions
Abstract
The overall objective of the proposed research is to experimentally demonstrate a logical qubit based on a 7-qubit quantum error-correction (QEC) code in an ion trap using up to 10 calcium ion physical qubits. Specific objectives include exploring and improving all aspects of system performance at the physical and logical levels, in order to pass the "break-even" point for quantum error correction on a fully functional encoded logical qubit. The overall proposed approach is to identify, understand, and mitigate major sources of errors and decoherence in the experimental system to achieve a total error below the error-correction threshold for the logical qubit. Specific aspects of the approach include: -Efficient Logical Encoding: Encode the information of one physical qubit in a 7-qubit topological color code compatible with transversal operations. Optimize the encoding, syndrome measurement, and feedback protocols for the underlying quantum-hardware capabilities to reduce resource requirements by a factor of 30 (compared to a brute-force implementation), thereby reducing the accumulation and propagation of errors. -Enhanced Physical-Layer Performance: Reduce base physical-qubit error rates through a switch to high-coherence ground-state qubits, for an anticipated 50-fold improvement in coherence over optical qubits. Employ a high-attenuation cryogenic trap to minimize the dominant noise from magnetic field fluctuations, with demonstrated shielding of>80 dB@ 50 Hz. -Layered Architecture: Supplement QEC with dynamical error suppression (DES) implemented at the physical layer. Replace all single and two-qubit operations with noise-optimized Walsh-modulated error-robust gates to improve physical-hardware error-rates, suppress correlated errors not efficiently handled by QEC, and reduce residual error correlations by a factor of> 100. -Ion-Trap Hardware: Suppress crosstalk to below 10"(-4) during gate operations and stabilizer measurements through deployment of segmented Sandia traps using optimized ion shuttling protocols. Add single-ion-pair addressing through fast beam steering, and implement dual-species experiments to allow ion-recooling, perform mixed-species gates for crosstalk-minimized syndrome extraction, and perform physical-layer noise.sensing and feedback stabilization. -Optimized Controller Hardware: Explore designs and deploy high-performance classical control infrastructure supporting the effort at both the algorithmic level and physical layer, including integration of physical-layer noise sensing, feedback control, beam-steering, pulse-optimization, and gate-modulation. Feedback latency for QEC will be reduced by more than 1,000 times relative to commercial controllers, such as those based on NIDAQ, with PC processing and communication being the main bottleneck. Details of the approach in each of these areas and a statement of work have been included in the proposal.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1610070
Entities
People
- Thomas Monz
Organizations
- Army Contracting Command
- United States Army
- University of Innsbruck