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arXiv · 2507.05514

Electron-molecule scattering via R-matrix variational algorithms on a quantum computer

Dario Picozzi·Jonathan Tennyson·Vincent Graves·Jimena D. Gorfinkiel
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Abstract

Electron-molecule collisions play a central role in both natural processes and modern technological applications, particularly in plasma processing. Conventional computational strategies such as the R-matrix method have been widely adopted yet encounter significant scaling challenges in treating more complex systems. In this work we present a quantum computational approach that utilises the variational quantum eigensolver (VQE) and variations thereof to overcome these limitations. We explore a number of methods, including the use of number projection operators and simultaneous optimisation. We demonstrate the feasibility of our method on a model problem of electron scattering from the hydrogen molecule, with numerical results obtained using a noiseless classical simulator. We recover the full spectrum of the Hamiltonian within a chosen symmetry sector. Moreover, the optimal circuit parameters directly encode the R-matrix boundary amplitudes needed for subsequent scattering computations. To our knowledge, this is the first application of quantum algorithms to electron--molecule scattering, and specifically the first formulation of the R-matrix inner-region problem on a quantum computer.

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Dario Picozzi, Jonathan Tennyson, Vincent Graves, Jimena D. Gorfinkiel. 2025-07-07. Electron-molecule scattering via R-matrix variational algorithms on a quantum computer. https://arxiv.org/abs/2507.05514

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