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arXiv · 2604.12465

Demonstrating Record Fidelity for the Quantum Fourier Transform

Philipp Aumann·Michael Fellner·David Alber·Max Cykiert·Christoph Fleckenstein·Roeland ter Hoeven·Leo Stenzel·Riccardo J. Valencia-Tortora·Wolfgang Lechner
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Abstract

We demonstrate the Parity Architecture on quantum hardware, using the quantum Fourier transform (QFT) as a benchmark. As a result, a record performance in both fidelity and qubit count is achieved using quantum processors with a native CZ-based instruction set. On the IBM Heron r3 chip, a process fidelity of the QFT algorithm of ${F \approx 10^{-2}}$ for ${N=50}$ qubits is achieved. The scaling of the speedup compared to previous swap-based methods is super-exponential $\mathcal{O}(\exp(N^2))$. Furthermore, we show that the scaling can be improved further by including iSWAP gates in the instruction set.

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Philipp Aumann, Michael Fellner, David Alber, Max Cykiert, Christoph Fleckenstein, Roeland ter Hoeven, Leo Stenzel, Riccardo J. Valencia-Tortora, Wolfgang Lechner. 2026-04-14. Demonstrating Record Fidelity for the Quantum Fourier Transform. https://arxiv.org/abs/2604.12465

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