Calculating non-linear response functions for multi-dimensional electronic spectroscopy using dyadic non-Markovian quantum state diffusion

TL;DR

This paper introduces a stochastic non-Markovian quantum state diffusion method combined with perturbation theory to efficiently simulate multi-dimensional electronic spectra of large molecular aggregates, accounting for environmental effects.

Contribution

The authors develop a novel approach that propagates NMQSD in a doubled Hilbert space with shared noise, enabling fast convergence for large system spectral calculations.

Findings

Fast convergence with respect to stochastic trajectories

Effective simulation of two-dimensional spectra

Applicable to large molecular aggregates

Abstract

We present a methodology for simulating multi-dimensional electronic spectra of molecular aggregates with coupling of electronic excitation to a structured environment using the stochastic non-Markovian quantum state diffusion (NMQSD) method in combination with perturbation theory for the response functions. A crucial aspect of our approach is that we propagate the NMQSD equation in a doubled system Hilbert space, but with the same noise. We demonstrate that our approach shows fast convergence with respect to the number of stochastic trajectories, providing a promising technique for numerical calculation of two-dimensional spectra of large molecular aggregates.