Variational Quantum Algorithms for Particle Track Reconstruction

TL;DR

This paper investigates the use of variational quantum algorithms for particle track reconstruction in high-energy physics, analyzing two formulations and designing quantum circuits with Monte Carlo Tree Search.

Contribution

It introduces two formulations for track reconstruction and employs quantum architecture search to optimize quantum circuits for this problem.

Findings

Quantum algorithms can model track reconstruction problems.

Quantum architecture search improves circuit design efficiency.

Experimental results demonstrate feasibility for various problem sizes.

Abstract

Quantum Computing is a rapidly developing field with the potential to tackle the increasing computational challenges faced in high-energy physics. In this work, we explore the potential and limitations of variational quantum algorithms in solving the particle track reconstruction problem. We present an analysis of two distinct formulations for identifying straight-line tracks in a multilayer detection system, inspired by the LHCb vertex detector. The first approach is formulated as a ground-state energy problem, while the second approach is formulated as a system of linear equations. This work addresses one of the main challenges when dealing with variational quantum algorithms on general problems, namely designing an expressive and efficient quantum ansatz working on tracking events with fixed detector geometry. For this purpose, we employed a quantum architecture search method based on Monte Carlo Tree Search to design the quantum circuits for different problem sizes. We provide experimental results to test our approach on both formulations for different problem sizes in terms of performance and computational cost.