Coupled-channel scattering from artificial confinement

Abstract:Artificial confinement encodes continuum scattering information in discrete, bound-state-like spectra, allowing reaction observables to be extracted with finite-basis or finite-domain methods. We apply this strategy to a two-channel cluster model of $^4$He with open $^3$H+p and $^3$He+n channels. We extract coupled-channel observables from spectra generated by a harmonic-oscillator (HO) trap, a spherical hard wall, and, within a single-partial-wave truncation, a periodic cubic box. The three geometries are formulated in a unified quantization-condition framework and benchmarked against a continuum $R$-matrix calculation. Above the second-channel threshold, several confined levels at a common scattering energy are combined in an overdetermined fit to determine two phase shifts and an inelasticity. Without Coulomb interactions, all three geometries yield consistent results for the $^1S_0$ and $^3P_1$ partial waves. With Coulomb interactions in the charged $^3$H+p channel, the HO and spherical-wall results also agree closely with the continuum reference. A Monte Carlo propagation study shows that spectral uncertainties are amplified near trap-function poles and along poorly conditioned directions associated with the inelasticity and phase-shift difference, whereas the phase-shift sum remains comparatively robust. These results provide a controlled benchmark for confinement-based scattering methods and delineate their strengths and limitations for future few-body and ab initio reaction calculations.

arXiv:2608.26865 [nucl-th]

(or arXiv:2608.26865v1 [nucl-th] for this version)

https://doi.org/10.48550/arXiv.2608.26865 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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