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Fault-tolerant execution of error-corrected quantum algorithms

Scaling up quantum algorithms to tackle high-impact problems in science and industry requires quantum error correction and fault tolerance. While progress has been made in experimentally realizing error-corrected primitives, the end-to-end execution of logical quantum algorithms using only fault-tolerant (FT) components has remained out of reach. We demonstrate the FT and error-corrected execution of two quantum algorithms, the Quantum Approximate Optimization Algorithm (QAOA) and the Harrow-Hassidim-Lloyd (HHL) algorithm applied to the Poisson equation, on Quantinuum H2 and Helios trapped-ion quantum processors using the $[[7,1,3]]$ Steane code. For QAOA circuits on 5 and 6 logical qubits, we show performance improvements from increasing the number of QAOA layers and the number of $T$ gates used to approximate logical rotations, despite increased physical circuit complexity. We further show that QAOA circuits with up to 8 logical qubits and 9 logical $T$ gates perform similarly to unencoded circuits. For the largest QAOA circuits we run, with 12 logical (97 physical) qubits and 2132 physical two-qubit gates, we still observe better-than-random performance. Finally, we show that adding active QEC cycles and increasing the repeat-until-success limit of state preparation subroutines can improve the performance of a quantum algorithm, thereby demonstrating critical capabilities of scalable FT quantum computation. Our results are enabled by an FT logical $T$ gate implementation with an infidelity of $\sim 2.6(4)\times10^{-3}$ and dynamic circuits with measurement-dependent feedback. Our work demonstrates near-break-even performance of complex, error-corrected algorithmic quantum circuits using only FT components.

La société Britannique Quantinuum atteint un seuil critique jugé « improbable avant des années » en inform ...

Ils ont dépassé le point de bascule… avec 94 qubits logiques Dans le monde quantique, il existe un moment très particulier que les physiciens anglosaxons appellent le break-even ou (point de basule ou point mort en français). C’est l’instant où un qubit protégé par correction d’erreurs devient réellement plus fiable…

La société Britannique Quantinuum atteint un seuil critique jugé « improbable avant des années » en inform ...

Ils ont dépassé le point de bascule… avec 94 qubits logiques Dans le monde quantique, il existe un moment très particulier que les physiciens anglosaxons appellent le break-even ou (point de basule ou point mort en français). C’est l’instant où un qubit protégé par correction d’erreurs devient réellement plus fiable…

Quantum Algorithm Beats Classical Tools On Complement Sampling Tasks - Slashdot

alternative_right shares a report from Phys.org: A team of researchers working at Quantinuum in the United Kingdom and QuSoft in the Netherlands has now developed a quantum algorithm that solves a specific sampling task -- known as complement sampling -- dramatically more efficiently than any classi...

Helios: A 98-qubit trapped-ion quantum computer

We report on Quantinuum Helios, a 98-qubit trapped-ion quantum processor based on the quantum charge-coupled device (QCCD) architecture. Helios features $^{137}$Ba$^{+}$ hyperfine qubits, all-to-all connectivity enabled by a rotatable ion storage ring connecting two quantum operation regions by a junction, speed improvements from parallelized operations, and a new software stack with real-time compilation of dynamic programs. Averaged over all operational zones in the system, we achieve average infidelities of $2.5(1)\times10^{-5}$ for single-qubit gates, $7.9(2)\times10^{-4}$ for two-qubit gates, and $4.8(6)\times10^{-4}$ for state preparation and measurement, none of which are fundamentally limited and likely able to be improved. These component infidelities are predictive of system-level performance in both random Clifford circuits and random circuit sampling, the latter demonstrating that Helios operates well beyond the reach of classical simulation and establishes a new frontier of fidelity and complexity for quantum computers.

量子科技是什麼？比人工智慧（AI）更重要嗎？ - TNL The News Lens 關鍵評論網

本文探討複雜難解的量子科技。其潛力巨大，有望在醫療、導航與最佳化等領域帶來革命。然而，其強大算力也對現行加密構成「Q日」威脅，引發重大資安疑慮，促使各界預先部署後量子加密技術。

Två speciella egenskaper gör den här kommersiella kvantdatorn unik

Blir Google, Microsoft eller IBM den stora vinnaren i kvantdatorkapplöpningen? Svaret är kanske Quantinuum, som grundades så sent som 2021.

New quantum hardware puts the mechanics in quantum mechanics

As a test case, the machine was used to test a model of superconductivity.