Ancilla-recycled RODEO filtering for nuclear scattering: A cross-platform benchmark on quantum processors

Abstract

Quantum computation of trapped spectra for nuclear scattering requires resource-efficient circuits and reliable energy inputs. We present a cross-platform benchmark of ancilla-recycled RODEO filtering for a four-dimensional effective Hamiltonian describing a trapped neutron--proton model. Static circuits on IonQ Forte-1 and dynamic circuits on IBM Aachen implement the same ideal ten-cycle all-zero accepted filter using twelve and three active qubits, respectively. Mid-circuit measurement and reset reduce the active qubit count by 75\% while retaining all controlled evolutions. The interleaved IBM peak-center offset from the exact level is $-0.017\pm 0.507\mathrm{keV}$, compared with $-0.568\pm 0.694\mathrm{keV}$ for IonQ (finite-shot bootstrap uncertainties). At \(ω=3.7~\mathrm{MeV}\), the modified effective range expansion maps both centers to finite-confinement scattering inputs consistent with the exact reference within propagated uncertainties. Three IBM batches exhibit center variations beyond finite-shot uncertainties (\(p=0.015\)), despite comparatively stable postselection amplitudes. Calibration-derived noisy simulations do not consistently reproduce the measured centers. Complete sampled support enables sample-based quantum diagonalization to recover the exact effective-space level, whereas larger-space simulator tests expose substantial errors from omitted configurations. The calculation validates one finite-confinement input, not a free-space phase shift. This benchmark provides a reusable circuit and validation protocol separating spectral precision, hardware repeatability, and sampled-subspace completeness for multilevel nuclear-scattering calculations.

arXiv comment27 pages, 5 figures