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This research proposes a scalable architecture for quantum low-density parity-check (qLDPC) codes by utilizing frequency-multiplexed parallel gates within two-dimensional ion crystals. By eliminating the need to physically move qubits, the method suppresses crosstalk and maintains robustness against trap frequency drift, enabling logical error rates as low as $10^{-12}$ for large-scale systems like a 512-ion crystal. This approach directly addresses critical bottlenecks in syndrome measurement speed and fidelity, advancing the practical feasibility of fault-tolerant quantum computing with trapped ions.
Frequency-Multiplexed Parallel Gates for Quantum LDPC Codes in a Two-Dimensional Ion Crystal
arXiv:2609.04081v1 Announce Type: new Abstract: Quantum low-density parity-check (qLDPC) codes admit high encoding rates but require nonlocal entangling gates for syndrome measurement. Instead of physically moving the qubits which slows down with the increasing qubit number, here we propose to achieve parallel nonlocal entangling gates on a two-dimensional (2D) ion crystal using frequency-multiplexing. Adiabatic conditions ensure the suppression of gate infidelity and crosstalk error, as well as their robustness against slow drift in the trap frequency which is a leading error source in ion trap. We consider a numerical example of a $[[248,10,18]]$ bivariate bicycle code on a 2D crystal of 512 ions. By optimizing the mapping of the qubits and the assignment of the frequency bands for multiplexing, we show that a moderate laser power is sufficient for parallelism, and that a logical error rate of $10^{-12}$ can be achieved under realistic noise parameters.
Abstract:Quantum low-density parity-check (qLDPC) codes admit high encoding rates but require nonlocal entangling gates for syndrome measurement. Instead of physically moving the qubits which slows down with the increasing qubit number, here we propose to achieve parallel nonlocal entangling gates on a two-dimensional (2D) ion crystal using frequency-multiplexing. Adiabatic conditions ensure the suppression of gate infidelity and crosstalk error, as well as their robustness against slow drift in the trap frequency which is a leading error source in ion trap. We consider a numerical example of a $[[248,10,18]]$ bivariate bicycle code on a 2D crystal of 512 ions. By optimizing the mapping of the qubits and the assignment of the frequency bands for multiplexing, we show that a moderate laser power is sufficient for parallelism, and that a logical error rate of $10^{-12}$ can be achieved under realistic noise parameters.
arXiv:2609.04081 [quant-ph]
(or arXiv:2609.04081v1 [quant-ph] for this version)
https://doi.org/10.48550/arXiv.2609.04081 Focus to learn more arXiv-issued DOI via DataCite (pending registration)
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