A driven-dissipative quantum Monte Carlo method for open quantum systems

TL;DR

This paper introduces a novel quantum Monte Carlo method for simulating open quantum systems' non-equilibrium dynamics, enabling efficient stochastic sampling of the density matrix evolution with reduced statistical error.

Contribution

It presents a real-time full configuration interaction quantum Monte Carlo approach with new techniques like initiator and importance sampling for open quantum systems.

Findings

Successfully applied to 2D XYZ spin model

Efficient sampling of non-equilibrium steady states

Reduced statistical errors in simulations

Abstract

We develop a real-time Full Configuration Interaction Quantum Monte Carlo approach for the modeling of driven-dissipative open quantum systems. The method enables stochastic sampling of the Liouville-von-Neumann time evolution of the density matrix, thanks to a massively parallel algorithm, thus providing estimates of observables on the non-equilibrium steady state. We present the underlying theory, and introduce initiator technique and importance sampling to reduce the statistical error. Finally, we demonstrate the efficiency of our approach by applying it to the driven- dissipative two-dimensional XYZ spin model on lattice.