Generalized quantum master equations can improve the accuracy of semiclassical predictions of multitime correlation functions

TL;DR

This paper demonstrates that using a multitime semiclassical generalized quantum master equation significantly enhances the accuracy and efficiency of simulating multitime quantum correlation functions, crucial for interpreting experimental data.

Contribution

It introduces a novel multitime semiclassical GQME approach that improves accuracy and computational efficiency over traditional methods for complex quantum systems.

Findings

Dramatic accuracy improvement of semiclassical dynamics.

Orders of magnitude computational efficiency gains.

Enhanced simulation of multitime quantum correlations.

Abstract

Multitime quantum correlation functions are central objects in physical science, offering a direct link between experimental observables and the dynamics of an underlying model. While experiments such as 2D spectroscopy and quantum control can now measure such quantities, the accurate simulation of such responses remains computationally expensive and sometimes impossible, depending on the system's complexity. A natural tool to employ is the generalized quantum master equation (GQME), which can offer computational savings by extending reference dynamics at a comparatively trivial cost. However, dynamical methods that can tackle chemical systems with atomistic resolution, such as those in the semiclassical hierarchy, often suffer from poor accuracy, limiting the credence one might lend to their results. By combining work on the accuracy-boosting formulation of semiclassical memory kernels with recent work on the multitime GQME, here we show for the first time that one can exploit a multitime semiclassical GQME to dramatically improve both the accuracy of coarse mean-field Ehrenfest dynamics and obtain orders of magnitude efficiency gains.