Efficient non-Markovian quantum dynamics using time-evolving matrix product operators

TL;DR

This paper introduces a new numerical method using time-evolving matrix product operators to efficiently simulate the dynamics of quantum systems strongly coupled to non-Markovian environments, surpassing previous limitations.

Contribution

The authors develop a general, efficient numerical approach for non-Markovian quantum dynamics using time-evolving matrix product operators, applicable to complex environmental interactions.

Findings

Successfully identified the localisation transition in the Ohmic spin-boson model.

Demonstrated the method's effectiveness on a two-spin system with separated environmental timescales.

Showcased the approach's flexibility for various non-Markovian quantum systems.

Abstract

In order to model realistic quantum devices it is necessary to simulate quantum systems strongly coupled to their environment. To date, most understanding of open quantum systems is restricted either to weak system-bath couplings, or to special cases where specific numerical techniques become effective. Here we present a novel general numerical approach to efficiently describe the time evolution of a quantum system coupled to a non-Markovian environment. We demonstrate the power and flexibility of our method by numerically identifying the localisation transition of the Ohmic spin-boson model, and considering a model with widely separated environmental timescales arising for a pair of spins embedded in a common environment.