A quantum strategy to compute the jet quenching parameter $\hat{q}$

TL;DR

This paper proposes a quantum computing approach to simulate the fundamental process of jet quenching, specifically momentum broadening, in high-energy nuclear physics, which is challenging for classical methods.

Contribution

It introduces a quantum simulation strategy for single particle momentum broadening, a key component of jet quenching, simplifying the quantum algorithm by focusing on a non-splitting process.

Findings

Quantum simulation of momentum broadening is feasible with simplified algorithms.

The approach models the medium as a QCD background field.

Results are relevant for high-energy collider phenomenology.

Abstract

Jet quenching, the modification of the properties of a QCD jet when the parton cascade takes place inside a medium, is an intrinsically quantum process, where color coherence effects play an essential role. Despite a very significant progress in the last years, the simulation of a full quantum medium induced cascade remains inaccessible to classical Monte Carlo parton showers. In this situation, alternative formulations are worth being tried and the fast developments in quantum computing provide a very promising direction. The goal of this paper is to introduce a strategy to quantum simulate single particle momentum broadening, the simplest building block of jet quenching. Momentum broadening is the modification of the quark or gluon transverse momentum due interactions with the underlying medium, modeled as a QCD background field. At the lowest order in $\alpha_s$ that we consider here, momentum broadening does not involve parton splittings and particle number is conserved, greatly simplifying the quantum algorithmic implementation. This quantity is, however, very relevant for the phenomenology of RHIC, LHC or the future EIC.