Quantum parallelism as a tool for ensemble spin dynamics calculations

TL;DR

This paper introduces a novel quantum simulation method that uses a single entangled state with random phases to efficiently compute spin dynamics, significantly reducing computational effort for ensemble quantum systems.

Contribution

The paper presents a new approach leveraging quantum parallelism and random phase superpositions to efficiently simulate ensemble spin dynamics with reduced computational complexity.

Findings

Method accurately predicts observable dynamics in spin systems.

Significantly decreases simulation time compared to traditional methods.

Validated on spin star and spin ladder models.

Abstract

Efficient simulations of quantum evolutions of spin-1/2 systems are relevant for ensemble quantum computation as well as in typical NMR experiments. We propose an efficient method to calculate the dynamics of an observable provided that the initial excitation is "local". It resorts a single entangled pure initial state built as a superposition, with random phases, of the pure elements that compose the mixture. This ensures self-averaging of any observable, drastically reducing the calculation time. The procedure is tested for two representative systems: a spin star (cluster with random long range interactions) and a spin ladder.