Real-Time Simulation of Open Quantum Spin Chains with Inchworm Method

TL;DR

This paper introduces a novel combined approach using the inchworm method and modular path integrals to efficiently simulate open quantum spin chains in real time, reducing computational challenges.

Contribution

The paper develops a new hybrid simulation technique that integrates inchworm and modular path integral methods for open quantum spin chains.

Findings

Significant suppression of the numerical sign problem.

Validated accuracy through extensive numerical experiments.

Analysis of computational cost behavior.

Abstract

We study the real-time simulation of open quantum systems, where the system is modeled by a spin chain, with each spin associated with its own harmonic bath. Our method couples the inchworm method for the spin-boson model and the modular path integral methodology for spin systems. In particular, the introduction of the inchworm method can significantly suppress the numerical sign problem. Both methods are tweaked to make them work seamlessly with each other. We represent our approach in the language of diagrammatic methods, and analyze the asymptotic behavior of the computational cost. Extensive numerical experiments are done to validate our method.