Variational quantum algorithm for non-Markovian quantum dynamics

TL;DR

This paper introduces a variational quantum algorithm designed to efficiently simulate non-Markovian quantum dynamics, capturing complex environmental effects on quantum systems using NISQ-compatible methods.

Contribution

The paper presents a novel variational quantum algorithm that employs Ehrenfest trajectories and Monte Carlo sampling to simulate non-Markovian quantum effects on quantum computers.

Findings

Algorithm accurately reproduces exact results for the spin-boson model.

Suitable for NISQ devices and complex system-bath interactions.

Demonstrates potential for scalable quantum simulations of open quantum systems.

Abstract

The simulation of non-Markovian quantum dynamics plays an important role in the understanding of charge and exciton dynamics in the condensed phase environment, and yet it remains computationally expensive on classical computers. We have developed a variational quantum algorithm that is capable of simulating non-Markovian quantum dynamics. The algorithm captures the non-Markovian effect by employing the Ehrenfect trajectories in the path integral formulation and the Monte Carlo sampling of the thermal distribution. We tested the algorithm with the spin-boson model on the quantum simulator and the results match well with the exact ones. The algorithm naturally fits into the parallel computing platform of the NISQ devices and is well suited for anharmonic system-bath interactions and multi-state systems.