Quantum Computing for Neutrino-nucleus Scattering

TL;DR

This paper explores how quantum computers can be used to calculate neutrino-nucleus scattering cross sections, analyzing resource requirements, scaling, and implementing small-scale models on current hardware with error mitigation.

Contribution

It introduces a variational quantum approach to model neutrino-nucleus interactions and assesses the feasibility on NISQ devices with error mitigation techniques.

Findings

Successful ground state calculation of the triton nucleus.

Implementation of time evolution on quantum hardware.

Error mitigation improves calculation fidelity.

Abstract

Neutrino-nucleus cross section uncertainties are expected to be a dominant systematic in future accelerator neutrino experiments. The cross sections are determined by the linear response of the nucleus to the weak interactions of the neutrino, and are dominated by energy and distance scales of the order of the separation between nucleons in the nucleus. These response functions are potentially an important early physics application of quantum computers. Here we present an analysis of the resources required and their expected scaling for scattering cross section calculations. We also examine simple small-scale neutrino-nucleus models on modern quantum hardware. In this paper, we use variational methods to obtain the ground state of a three nucleon system (the triton) and then implement the relevant time evolution. In order to tame the errors in present-day NISQ devices, we explore the use of different error-mitigation techniques to increase the fidelity of the calculations.