Proton-proton scattering on a quantum computer

TL;DR

This paper demonstrates calculating proton-proton scattering phase shifts at low energy using a hybrid quantum-classical algorithm on a quantum computer, combining nuclear physics theory with quantum simulation techniques.

Contribution

It introduces a method to compute proton-proton scattering phase shifts on a quantum computer using a hybrid variational approach and lattice discretization.

Findings

Accurately reproduces low-momentum phase shifts.

Uses a hybrid quantum-classical variational algorithm.

Adapts nuclear scattering theory to quantum computing framework.

Abstract

Scattering of charged particles is ubiquitous in nuclear physics. We calculate the proton-proton $s$-wave phase shift at low energy relevant to solar physics. The phase shift is calculated from the ratio of the regular and irregular solutions to the radial Schr\"odinger equation on a hard spherical wall boundary for the ground state. The ground state energy is calculated using a hybrid quantum-classical variational algorithm. A theory with short-ranged nuclear interaction in the presence of the long-ranged Coulomb force is used to describe the scattering. The theory is discretized on a spatial lattice for adaptation to the quantum computer in the second quantized language. The phase shifts at low momenta are accurately reproduced.