Simulating Markovian open quantum systems using higher-order series expansion

TL;DR

This paper introduces a new quantum algorithm for simulating Markovian open quantum systems that is conceptually simpler and uses basic quantum primitives, leveraging higher-order series expansion and Gaussian quadrature.

Contribution

The authors develop a novel mathematical approach using higher-order series expansion and Gaussian quadrature for efficient quantum simulation of open systems, applicable to time-dependent Lindbladians.

Findings

Algorithm scales linearly with evolution time

Uses simple quantum primitives without compressed encoding

Potentially improves simulation of time-dependent Hamiltonians

Abstract

We present an efficient quantum algorithm for simulating the dynamics of Markovian open quantum systems. The performance of our algorithm is similar to the previous state-of-the-art quantum algorithm, i.e., it scales linearly in evolution time and poly-logarithmically in inverse precision. However, our algorithm is conceptually cleaner, and it only uses simple quantum primitives without compressed encoding. Our approach is based on a novel mathematical treatment of the evolution map, which involves a higher-order series expansion based on Duhamel's principle and approximating multiple integrals using scaled Gaussian quadrature. Our method easily generalizes to simulating quantum dynamics with time-dependent Lindbladians. Furthermore, our method of approximating multiple integrals using scaled Gaussian quadrature could potentially be used to produce a more efficient approximation of time-ordered integrals, and therefore can simplify existing quantum algorithms for simulating time-dependent Hamiltonians based on a truncated Dyson series.