Improved Fermionic Scattering for the NISQ Era

TL;DR

This paper introduces a new fermionic scattering state preparation method optimized for NISQ quantum computers, reducing circuit depth while maintaining accuracy in simulating fermionic systems.

Contribution

It modifies existing state preparation techniques to localize fermionic wave packets, nearly halves circuit depth, and demonstrates effectiveness through simulations and hardware implementation.

Findings

Approximated wave packets approach exact solutions in weakly interacting theories

Circuit depth is reduced by nearly 50%

Method is successfully implemented on IonQ's quantum hardware

Abstract

In the era of noisy intermediate scale quantum (NISQ) hardware, digital quantum computers are limited to shallow circuits on the order of a thousand layers due to system noise and qubit decoherence. Thus, every step of a simulation must be as efficient as possible. Modifying the recent Givens Rotation state preparation by Chai et al and ladder operator block encoding method by Simon et al, we propose a scattering state preparation method that approximates the fermionic wave packets by localizing them in space, reducing circuit depth by nearly half, while also preserving fermionic anti-commutation relations. Using MPS simulations, we show that these approximated wave packets approach the exact wave packets in weakly interacting critical theories; and then show its immediate application on modern day hardware with IonQ's Forte 1 machine.