Proton-proton scattering on a quantum computer

Scattering of charged particles plays a fundamental role in nuclear physics. In this work, we compute the proton-proton S-wave phase shift at low energies relevant to solar fusion processes. The phase shift is determined from the ratio of the regular and irregular solutions of the radial Schrodinger equation subject to a hard-wall boundary condition at the ground state. The ground-state energy is obtained through a hybrid quantum-classical variational algorithm, enabling a quantum simulation of the scattering process. The underlying theory combines a short-range nuclear interaction with the long-range Coulomb potential, formulated within a lattice discretization of space and expressed in the second-quantized framework to suit quantum hardware implementation. Our results show that the computed phase shifts at low momenta are in excellent agreement with expected values.